X-Git-Url: http://wien.tomnetworks.com/gitweb/?p=hs-boehmgc.git;a=blobdiff_plain;f=gc-7.2%2Fos_dep.c;fp=gc-7.2%2Fos_dep.c;h=da0f24d737c4b883d2f14838edbcea6a57e9b628;hp=0000000000000000000000000000000000000000;hb=324587ba93dc77f37406d41fd2a20d0e0d94fb1d;hpb=2a4ea609491b225a1ceb06da70396e93916f137a diff --git a/gc-7.2/os_dep.c b/gc-7.2/os_dep.c new file mode 100644 index 0000000..da0f24d --- /dev/null +++ b/gc-7.2/os_dep.c @@ -0,0 +1,4737 @@ +/* + * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers + * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. + * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved. + * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved. + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program + * for any purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is granted, + * provided the above notices are retained, and a notice that the code was + * modified is included with the above copyright notice. + */ + +#include "private/gc_priv.h" + +#if defined(LINUX) && !defined(POWERPC) +# include +# if (LINUX_VERSION_CODE <= 0x10400) + /* Ugly hack to get struct sigcontext_struct definition. Required */ + /* for some early 1.3.X releases. Will hopefully go away soon. */ + /* in some later Linux releases, asm/sigcontext.h may have to */ + /* be included instead. */ +# define __KERNEL__ +# include +# undef __KERNEL__ +# else + /* Kernels prior to 2.1.1 defined struct sigcontext_struct instead of */ + /* struct sigcontext. libc6 (glibc2) uses "struct sigcontext" in */ + /* prototypes, so we have to include the top-level sigcontext.h to */ + /* make sure the former gets defined to be the latter if appropriate. */ +# include +# if 2 <= __GLIBC__ +# if 2 == __GLIBC__ && 0 == __GLIBC_MINOR__ + /* glibc 2.1 no longer has sigcontext.h. But signal.h */ + /* has the right declaration for glibc 2.1. */ +# include +# endif /* 0 == __GLIBC_MINOR__ */ +# else /* not 2 <= __GLIBC__ */ + /* libc5 doesn't have : go directly with the kernel */ + /* one. Check LINUX_VERSION_CODE to see which we should reference. */ +# include +# endif /* 2 <= __GLIBC__ */ +# endif +#endif + +#if !defined(OS2) && !defined(PCR) && !defined(AMIGA) && !defined(MACOS) \ + && !defined(MSWINCE) && !defined(__CC_ARM) +# include +# if !defined(MSWIN32) +# include +# endif +#endif + +#include +#if defined(MSWINCE) || defined(SN_TARGET_PS3) +# define SIGSEGV 0 /* value is irrelevant */ +#else +# include +#endif + +#if defined(UNIX_LIKE) || defined(CYGWIN32) || defined(NACL) +# include +#endif + +#if defined(LINUX) || defined(LINUX_STACKBOTTOM) +# include +#endif + +/* Blatantly OS dependent routines, except for those that are related */ +/* to dynamic loading. */ + +#ifdef AMIGA +# define GC_AMIGA_DEF +# include "extra/AmigaOS.c" +# undef GC_AMIGA_DEF +#endif + +#if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32) +# ifndef WIN32_LEAN_AND_MEAN +# define WIN32_LEAN_AND_MEAN 1 +# endif +# define NOSERVICE +# include + /* It's not clear this is completely kosher under Cygwin. But it */ + /* allows us to get a working GC_get_stack_base. */ +#endif + +#ifdef MACOS +# include +#endif + +#ifdef IRIX5 +# include +# include /* for locking */ +#endif + +#if defined(LINUX) || defined(FREEBSD) || defined(SOLARIS) || defined(IRIX5) \ + || ((defined(USE_MMAP) || defined(USE_MUNMAP)) \ + && !defined(MSWIN32) && !defined(MSWINCE)) +# define MMAP_SUPPORTED +#endif + +#if defined(MMAP_SUPPORTED) || defined(ADD_HEAP_GUARD_PAGES) +# if defined(USE_MUNMAP) && !defined(USE_MMAP) +# error "invalid config - USE_MUNMAP requires USE_MMAP" +# endif +# include +# include +# include +# include +#endif + +#ifdef DARWIN + /* for get_etext and friends */ +# include +#endif + +#ifdef DJGPP + /* Apparently necessary for djgpp 2.01. May cause problems with */ + /* other versions. */ + typedef long unsigned int caddr_t; +#endif + +#ifdef PCR +# include "il/PCR_IL.h" +# include "th/PCR_ThCtl.h" +# include "mm/PCR_MM.h" +#endif + +#if !defined(NO_EXECUTE_PERMISSION) + STATIC GC_bool GC_pages_executable = TRUE; +#else + STATIC GC_bool GC_pages_executable = FALSE; +#endif +#define IGNORE_PAGES_EXECUTABLE 1 + /* Undefined on GC_pages_executable real use. */ + +#ifdef NEED_PROC_MAPS +/* We need to parse /proc/self/maps, either to find dynamic libraries, */ +/* and/or to find the register backing store base (IA64). Do it once */ +/* here. */ + +#define READ read + +/* Repeatedly perform a read call until the buffer is filled or */ +/* we encounter EOF. */ +STATIC ssize_t GC_repeat_read(int fd, char *buf, size_t count) +{ + size_t num_read = 0; + ssize_t result; + + ASSERT_CANCEL_DISABLED(); + while (num_read < count) { + result = READ(fd, buf + num_read, count - num_read); + if (result < 0) return result; + if (result == 0) break; + num_read += result; + } + return num_read; +} + +#ifdef THREADS + /* Determine the length of a file by incrementally reading it into a */ + /* This would be silly to use on a file supporting lseek, but Linux */ + /* /proc files usually do not. */ + STATIC size_t GC_get_file_len(int f) + { + size_t total = 0; + ssize_t result; +# define GET_FILE_LEN_BUF_SZ 500 + char buf[GET_FILE_LEN_BUF_SZ]; + + do { + result = read(f, buf, GET_FILE_LEN_BUF_SZ); + if (result == -1) return 0; + total += result; + } while (result > 0); + return total; + } + + STATIC size_t GC_get_maps_len(void) + { + int f = open("/proc/self/maps", O_RDONLY); + size_t result; + if (f < 0) return 0; /* treat missing file as empty */ + result = GC_get_file_len(f); + close(f); + return result; + } +#endif /* THREADS */ + +/* Copy the contents of /proc/self/maps to a buffer in our address */ +/* space. Return the address of the buffer, or zero on failure. */ +/* This code could be simplified if we could determine its size ahead */ +/* of time. */ +GC_INNER char * GC_get_maps(void) +{ + int f; + ssize_t result; + static char *maps_buf = NULL; + static size_t maps_buf_sz = 1; + size_t maps_size, old_maps_size = 0; + + /* The buffer is essentially static, so there must be a single client. */ + GC_ASSERT(I_HOLD_LOCK()); + + /* Note that in the presence of threads, the maps file can */ + /* essentially shrink asynchronously and unexpectedly as */ + /* threads that we already think of as dead release their */ + /* stacks. And there is no easy way to read the entire */ + /* file atomically. This is arguably a misfeature of the */ + /* /proc/.../maps interface. */ + + /* Since we don't believe the file can grow */ + /* asynchronously, it should suffice to first determine */ + /* the size (using lseek or read), and then to reread the */ + /* file. If the size is inconsistent we have to retry. */ + /* This only matters with threads enabled, and if we use */ + /* this to locate roots (not the default). */ + +# ifdef THREADS + /* Determine the initial size of /proc/self/maps. */ + /* Note that lseek doesn't work, at least as of 2.6.15. */ + maps_size = GC_get_maps_len(); + if (0 == maps_size) return 0; +# else + maps_size = 4000; /* Guess */ +# endif + + /* Read /proc/self/maps, growing maps_buf as necessary. */ + /* Note that we may not allocate conventionally, and */ + /* thus can't use stdio. */ + do { + while (maps_size >= maps_buf_sz) { + /* Grow only by powers of 2, since we leak "too small" buffers.*/ + while (maps_size >= maps_buf_sz) maps_buf_sz *= 2; + maps_buf = GC_scratch_alloc(maps_buf_sz); +# ifdef THREADS + /* Recompute initial length, since we allocated. */ + /* This can only happen a few times per program */ + /* execution. */ + maps_size = GC_get_maps_len(); + if (0 == maps_size) return 0; +# endif + if (maps_buf == 0) return 0; + } + GC_ASSERT(maps_buf_sz >= maps_size + 1); + f = open("/proc/self/maps", O_RDONLY); + if (-1 == f) return 0; +# ifdef THREADS + old_maps_size = maps_size; +# endif + maps_size = 0; + do { + result = GC_repeat_read(f, maps_buf, maps_buf_sz-1); + if (result <= 0) + break; + maps_size += result; + } while ((size_t)result == maps_buf_sz-1); + close(f); + if (result <= 0) + return 0; +# ifdef THREADS + if (maps_size > old_maps_size) { + if (GC_print_stats) + GC_log_printf( + "Unexpected maps size growth from %lu to %lu\n", + (unsigned long)old_maps_size, + (unsigned long)maps_size); + ABORT("Unexpected asynchronous /proc/self/maps growth: " + "unregistered thread?"); + } +# endif + } while (maps_size >= maps_buf_sz || maps_size < old_maps_size); + /* In the single-threaded case, the second clause is false. */ + maps_buf[maps_size] = '\0'; + + /* Apply fn to result. */ + return maps_buf; +} + +/* + * GC_parse_map_entry parses an entry from /proc/self/maps so we can + * locate all writable data segments that belong to shared libraries. + * The format of one of these entries and the fields we care about + * is as follows: + * XXXXXXXX-XXXXXXXX r-xp 00000000 30:05 260537 name of mapping...\n + * ^^^^^^^^ ^^^^^^^^ ^^^^ ^^ + * start end prot maj_dev + * + * Note that since about august 2003 kernels, the columns no longer have + * fixed offsets on 64-bit kernels. Hence we no longer rely on fixed offsets + * anywhere, which is safer anyway. + */ + +/* Assign various fields of the first line in buf_ptr to (*start), */ +/* (*end), (*prot), (*maj_dev) and (*mapping_name). mapping_name may */ +/* be NULL. (*prot) and (*mapping_name) are assigned pointers into the */ +/* original buffer. */ +GC_INNER char *GC_parse_map_entry(char *buf_ptr, ptr_t *start, ptr_t *end, + char **prot, unsigned int *maj_dev, + char **mapping_name) +{ + char *start_start, *end_start, *maj_dev_start; + char *p; + char *endp; + + if (buf_ptr == NULL || *buf_ptr == '\0') { + return NULL; + } + + p = buf_ptr; + while (isspace(*p)) ++p; + start_start = p; + GC_ASSERT(isxdigit(*start_start)); + *start = (ptr_t)strtoul(start_start, &endp, 16); p = endp; + GC_ASSERT(*p=='-'); + + ++p; + end_start = p; + GC_ASSERT(isxdigit(*end_start)); + *end = (ptr_t)strtoul(end_start, &endp, 16); p = endp; + GC_ASSERT(isspace(*p)); + + while (isspace(*p)) ++p; + GC_ASSERT(*p == 'r' || *p == '-'); + *prot = p; + /* Skip past protection field to offset field */ + while (!isspace(*p)) ++p; while (isspace(*p)) ++p; + GC_ASSERT(isxdigit(*p)); + /* Skip past offset field, which we ignore */ + while (!isspace(*p)) ++p; while (isspace(*p)) ++p; + maj_dev_start = p; + GC_ASSERT(isxdigit(*maj_dev_start)); + *maj_dev = strtoul(maj_dev_start, NULL, 16); + + if (mapping_name == 0) { + while (*p && *p++ != '\n'); + } else { + while (*p && *p != '\n' && *p != '/' && *p != '[') p++; + *mapping_name = p; + while (*p && *p++ != '\n'); + } + + return p; +} + +#if defined(IA64) || defined(INCLUDE_LINUX_THREAD_DESCR) + /* Try to read the backing store base from /proc/self/maps. */ + /* Return the bounds of the writable mapping with a 0 major device, */ + /* which includes the address passed as data. */ + /* Return FALSE if there is no such mapping. */ + GC_INNER GC_bool GC_enclosing_mapping(ptr_t addr, ptr_t *startp, + ptr_t *endp) + { + char *prot; + ptr_t my_start, my_end; + unsigned int maj_dev; + char *maps = GC_get_maps(); + char *buf_ptr = maps; + + if (0 == maps) return(FALSE); + for (;;) { + buf_ptr = GC_parse_map_entry(buf_ptr, &my_start, &my_end, + &prot, &maj_dev, 0); + + if (buf_ptr == NULL) return FALSE; + if (prot[1] == 'w' && maj_dev == 0) { + if (my_end > addr && my_start <= addr) { + *startp = my_start; + *endp = my_end; + return TRUE; + } + } + } + return FALSE; + } +#endif /* IA64 || INCLUDE_LINUX_THREAD_DESCR */ + +#if defined(REDIRECT_MALLOC) + /* Find the text(code) mapping for the library whose name, after */ + /* stripping the directory part, starts with nm. */ + GC_INNER GC_bool GC_text_mapping(char *nm, ptr_t *startp, ptr_t *endp) + { + size_t nm_len = strlen(nm); + char *prot; + char *map_path; + ptr_t my_start, my_end; + unsigned int maj_dev; + char *maps = GC_get_maps(); + char *buf_ptr = maps; + + if (0 == maps) return(FALSE); + for (;;) { + buf_ptr = GC_parse_map_entry(buf_ptr, &my_start, &my_end, + &prot, &maj_dev, &map_path); + + if (buf_ptr == NULL) return FALSE; + if (prot[0] == 'r' && prot[1] == '-' && prot[2] == 'x') { + char *p = map_path; + /* Set p to point just past last slash, if any. */ + while (*p != '\0' && *p != '\n' && *p != ' ' && *p != '\t') ++p; + while (*p != '/' && p >= map_path) --p; + ++p; + if (strncmp(nm, p, nm_len) == 0) { + *startp = my_start; + *endp = my_end; + return TRUE; + } + } + } + return FALSE; + } +#endif /* REDIRECT_MALLOC */ + +#ifdef IA64 + static ptr_t backing_store_base_from_proc(void) + { + ptr_t my_start, my_end; + if (!GC_enclosing_mapping(GC_save_regs_in_stack(), &my_start, &my_end)) { + if (GC_print_stats) { + GC_log_printf("Failed to find backing store base from /proc\n"); + } + return 0; + } + return my_start; + } +#endif + +#endif /* NEED_PROC_MAPS */ + +#if defined(SEARCH_FOR_DATA_START) + /* The I386 case can be handled without a search. The Alpha case */ + /* used to be handled differently as well, but the rules changed */ + /* for recent Linux versions. This seems to be the easiest way to */ + /* cover all versions. */ + +# if defined(LINUX) || defined(HURD) + /* Some Linux distributions arrange to define __data_start. Some */ + /* define data_start as a weak symbol. The latter is technically */ + /* broken, since the user program may define data_start, in which */ + /* case we lose. Nonetheless, we try both, preferring __data_start.*/ + /* We assume gcc-compatible pragmas. */ +# pragma weak __data_start + extern int __data_start[]; +# pragma weak data_start + extern int data_start[]; +# endif /* LINUX */ + extern int _end[]; + + ptr_t GC_data_start = NULL; + + ptr_t GC_find_limit(ptr_t, GC_bool); + + GC_INNER void GC_init_linux_data_start(void) + { + +# if defined(LINUX) || defined(HURD) + /* Try the easy approaches first: */ + if ((ptr_t)__data_start != 0) { + GC_data_start = (ptr_t)(__data_start); + return; + } + if ((ptr_t)data_start != 0) { + GC_data_start = (ptr_t)(data_start); + return; + } +# endif /* LINUX */ + GC_data_start = GC_find_limit((ptr_t)(_end), FALSE); + } +#endif /* SEARCH_FOR_DATA_START */ + +#ifdef ECOS + +# ifndef ECOS_GC_MEMORY_SIZE +# define ECOS_GC_MEMORY_SIZE (448 * 1024) +# endif /* ECOS_GC_MEMORY_SIZE */ + + /* FIXME: This is a simple way of allocating memory which is */ + /* compatible with ECOS early releases. Later releases use a more */ + /* sophisticated means of allocating memory than this simple static */ + /* allocator, but this method is at least bound to work. */ + static char ecos_gc_memory[ECOS_GC_MEMORY_SIZE]; + static char *ecos_gc_brk = ecos_gc_memory; + + static void *tiny_sbrk(ptrdiff_t increment) + { + void *p = ecos_gc_brk; + ecos_gc_brk += increment; + if (ecos_gc_brk > ecos_gc_memory + sizeof(ecos_gc_memory)) { + ecos_gc_brk -= increment; + return NULL; + } + return p; + } +# define sbrk tiny_sbrk +#endif /* ECOS */ + +#if defined(NETBSD) && defined(__ELF__) + ptr_t GC_data_start = NULL; + ptr_t GC_find_limit(ptr_t, GC_bool); + + extern char **environ; + + GC_INNER void GC_init_netbsd_elf(void) + { + /* This may need to be environ, without the underscore, for */ + /* some versions. */ + GC_data_start = GC_find_limit((ptr_t)&environ, FALSE); + } +#endif /* NETBSD */ + +#ifdef OPENBSD + static struct sigaction old_segv_act; + STATIC sigjmp_buf GC_jmp_buf_openbsd; + +# ifdef THREADS +# include + extern sigset_t __syscall(quad_t, ...); +# endif + + /* Don't use GC_find_limit() because siglongjmp() outside of the */ + /* signal handler by-passes our userland pthreads lib, leaving */ + /* SIGSEGV and SIGPROF masked. Instead, use this custom one that */ + /* works-around the issues. */ + + /*ARGSUSED*/ + STATIC void GC_fault_handler_openbsd(int sig) + { + siglongjmp(GC_jmp_buf_openbsd, 1); + } + + /* Return the first non-addressible location > p or bound. */ + /* Requires the allocation lock. */ + STATIC ptr_t GC_find_limit_openbsd(ptr_t p, ptr_t bound) + { + static volatile ptr_t result; + /* Safer if static, since otherwise it may not be */ + /* preserved across the longjmp. Can safely be */ + /* static since it's only called with the */ + /* allocation lock held. */ + + struct sigaction act; + size_t pgsz = (size_t)sysconf(_SC_PAGESIZE); + GC_ASSERT(I_HOLD_LOCK()); + + act.sa_handler = GC_fault_handler_openbsd; + sigemptyset(&act.sa_mask); + act.sa_flags = SA_NODEFER | SA_RESTART; + sigaction(SIGSEGV, &act, &old_segv_act); + + if (sigsetjmp(GC_jmp_buf_openbsd, 1) == 0) { + result = (ptr_t)((word)p & ~(pgsz-1)); + for (;;) { + result += pgsz; + if (result >= bound) { + result = bound; + break; + } + GC_noop1((word)(*result)); + } + } + +# ifdef THREADS + /* Due to the siglongjump we need to manually unmask SIGPROF. */ + __syscall(SYS_sigprocmask, SIG_UNBLOCK, sigmask(SIGPROF)); +# endif + + sigaction(SIGSEGV, &old_segv_act, 0); + return(result); + } + + /* Return first addressable location > p or bound. */ + /* Requires the allocation lock. */ + STATIC ptr_t GC_skip_hole_openbsd(ptr_t p, ptr_t bound) + { + static volatile ptr_t result; + static volatile int firstpass; + + struct sigaction act; + size_t pgsz = (size_t)sysconf(_SC_PAGESIZE); + GC_ASSERT(I_HOLD_LOCK()); + + act.sa_handler = GC_fault_handler_openbsd; + sigemptyset(&act.sa_mask); + act.sa_flags = SA_NODEFER | SA_RESTART; + sigaction(SIGSEGV, &act, &old_segv_act); + + firstpass = 1; + result = (ptr_t)((word)p & ~(pgsz-1)); + if (sigsetjmp(GC_jmp_buf_openbsd, 1) != 0 || firstpass) { + firstpass = 0; + result += pgsz; + if (result >= bound) { + result = bound; + } else { + GC_noop1((word)(*result)); + } + } + + sigaction(SIGSEGV, &old_segv_act, 0); + return(result); + } +#endif /* OPENBSD */ + +# ifdef OS2 + +# include + +# if !defined(__IBMC__) && !defined(__WATCOMC__) /* e.g. EMX */ + +struct exe_hdr { + unsigned short magic_number; + unsigned short padding[29]; + long new_exe_offset; +}; + +#define E_MAGIC(x) (x).magic_number +#define EMAGIC 0x5A4D +#define E_LFANEW(x) (x).new_exe_offset + +struct e32_exe { + unsigned char magic_number[2]; + unsigned char byte_order; + unsigned char word_order; + unsigned long exe_format_level; + unsigned short cpu; + unsigned short os; + unsigned long padding1[13]; + unsigned long object_table_offset; + unsigned long object_count; + unsigned long padding2[31]; +}; + +#define E32_MAGIC1(x) (x).magic_number[0] +#define E32MAGIC1 'L' +#define E32_MAGIC2(x) (x).magic_number[1] +#define E32MAGIC2 'X' +#define E32_BORDER(x) (x).byte_order +#define E32LEBO 0 +#define E32_WORDER(x) (x).word_order +#define E32LEWO 0 +#define E32_CPU(x) (x).cpu +#define E32CPU286 1 +#define E32_OBJTAB(x) (x).object_table_offset +#define E32_OBJCNT(x) (x).object_count + +struct o32_obj { + unsigned long size; + unsigned long base; + unsigned long flags; + unsigned long pagemap; + unsigned long mapsize; + unsigned long reserved; +}; + +#define O32_FLAGS(x) (x).flags +#define OBJREAD 0x0001L +#define OBJWRITE 0x0002L +#define OBJINVALID 0x0080L +#define O32_SIZE(x) (x).size +#define O32_BASE(x) (x).base + +# else /* IBM's compiler */ + +/* A kludge to get around what appears to be a header file bug */ +# ifndef WORD +# define WORD unsigned short +# endif +# ifndef DWORD +# define DWORD unsigned long +# endif + +# define EXE386 1 +# include +# include + +# endif /* __IBMC__ */ + +# define INCL_DOSEXCEPTIONS +# define INCL_DOSPROCESS +# define INCL_DOSERRORS +# define INCL_DOSMODULEMGR +# define INCL_DOSMEMMGR +# include + +# endif /* OS/2 */ + +/* Find the page size */ +GC_INNER word GC_page_size = 0; + +#if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32) +# ifndef VER_PLATFORM_WIN32_CE +# define VER_PLATFORM_WIN32_CE 3 +# endif + +# if defined(MSWINCE) && defined(THREADS) + GC_INNER GC_bool GC_dont_query_stack_min = FALSE; +# endif + + GC_INNER void GC_setpagesize(void) + { + GetSystemInfo(&GC_sysinfo); + GC_page_size = GC_sysinfo.dwPageSize; +# if defined(MSWINCE) && !defined(_WIN32_WCE_EMULATION) + { + OSVERSIONINFO verInfo; + /* Check the current WinCE version. */ + verInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO); + if (!GetVersionEx(&verInfo)) + ABORT("GetVersionEx failed"); + if (verInfo.dwPlatformId == VER_PLATFORM_WIN32_CE && + verInfo.dwMajorVersion < 6) { + /* Only the first 32 MB of address space belongs to the */ + /* current process (unless WinCE 6.0+ or emulation). */ + GC_sysinfo.lpMaximumApplicationAddress = (LPVOID)((word)32 << 20); +# ifdef THREADS + /* On some old WinCE versions, it's observed that */ + /* VirtualQuery calls don't work properly when used to */ + /* get thread current stack committed minimum. */ + if (verInfo.dwMajorVersion < 5) + GC_dont_query_stack_min = TRUE; +# endif + } + } +# endif + } + +# ifndef CYGWIN32 +# define is_writable(prot) ((prot) == PAGE_READWRITE \ + || (prot) == PAGE_WRITECOPY \ + || (prot) == PAGE_EXECUTE_READWRITE \ + || (prot) == PAGE_EXECUTE_WRITECOPY) + /* Return the number of bytes that are writable starting at p. */ + /* The pointer p is assumed to be page aligned. */ + /* If base is not 0, *base becomes the beginning of the */ + /* allocation region containing p. */ + STATIC word GC_get_writable_length(ptr_t p, ptr_t *base) + { + MEMORY_BASIC_INFORMATION buf; + word result; + word protect; + + result = VirtualQuery(p, &buf, sizeof(buf)); + if (result != sizeof(buf)) ABORT("Weird VirtualQuery result"); + if (base != 0) *base = (ptr_t)(buf.AllocationBase); + protect = (buf.Protect & ~(PAGE_GUARD | PAGE_NOCACHE)); + if (!is_writable(protect)) { + return(0); + } + if (buf.State != MEM_COMMIT) return(0); + return(buf.RegionSize); + } + + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb) + { + ptr_t trunc_sp = (ptr_t)((word)GC_approx_sp() & ~(GC_page_size - 1)); + /* FIXME: This won't work if called from a deeply recursive */ + /* client code (and the committed stack space has grown). */ + word size = GC_get_writable_length(trunc_sp, 0); + GC_ASSERT(size != 0); + sb -> mem_base = trunc_sp + size; + return GC_SUCCESS; + } +# else /* CYGWIN32 */ + /* An alternate version for Cygwin (adapted from Dave Korn's */ + /* gcc version of boehm-gc). */ + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb) + { + extern void * _tlsbase __asm__ ("%fs:4"); + sb -> mem_base = _tlsbase; + return GC_SUCCESS; + } +# endif /* CYGWIN32 */ +# define HAVE_GET_STACK_BASE + +#else /* !MSWIN32 */ + GC_INNER void GC_setpagesize(void) + { +# if defined(MPROTECT_VDB) || defined(PROC_VDB) || defined(USE_MMAP) + GC_page_size = GETPAGESIZE(); + if (!GC_page_size) ABORT("getpagesize() failed"); +# else + /* It's acceptable to fake it. */ + GC_page_size = HBLKSIZE; +# endif + } +#endif /* !MSWIN32 */ + +#ifdef BEOS +# include + + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb) + { + thread_info th; + get_thread_info(find_thread(NULL),&th); + sb->mem_base = th.stack_end; + return GC_SUCCESS; + } +# define HAVE_GET_STACK_BASE +#endif /* BEOS */ + +#ifdef OS2 + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb) + { + PTIB ptib; /* thread information block */ + PPIB ppib; + if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) { + ABORT("DosGetInfoBlocks failed"); + } + sb->mem_base = ptib->tib_pstacklimit; + return GC_SUCCESS; + } +# define HAVE_GET_STACK_BASE +#endif /* OS2 */ + +# ifdef AMIGA +# define GC_AMIGA_SB +# include "extra/AmigaOS.c" +# undef GC_AMIGA_SB +# endif /* AMIGA */ + +# if defined(NEED_FIND_LIMIT) || defined(UNIX_LIKE) + + typedef void (*GC_fault_handler_t)(int); + +# if defined(SUNOS5SIGS) || defined(IRIX5) || defined(OSF1) \ + || defined(HURD) || defined(NETBSD) + static struct sigaction old_segv_act; +# if defined(_sigargs) /* !Irix6.x */ || defined(HPUX) \ + || defined(HURD) || defined(NETBSD) || defined(FREEBSD) + static struct sigaction old_bus_act; +# endif +# else + static GC_fault_handler_t old_segv_handler, old_bus_handler; +# endif + + GC_INNER void GC_set_and_save_fault_handler(GC_fault_handler_t h) + { +# if defined(SUNOS5SIGS) || defined(IRIX5) \ + || defined(OSF1) || defined(HURD) || defined(NETBSD) + struct sigaction act; + + act.sa_handler = h; +# ifdef SIGACTION_FLAGS_NODEFER_HACK + /* Was necessary for Solaris 2.3 and very temporary */ + /* NetBSD bugs. */ + act.sa_flags = SA_RESTART | SA_NODEFER; +# else + act.sa_flags = SA_RESTART; +# endif + + (void) sigemptyset(&act.sa_mask); +# ifdef GC_IRIX_THREADS + /* Older versions have a bug related to retrieving and */ + /* and setting a handler at the same time. */ + (void) sigaction(SIGSEGV, 0, &old_segv_act); + (void) sigaction(SIGSEGV, &act, 0); +# else + (void) sigaction(SIGSEGV, &act, &old_segv_act); +# if defined(IRIX5) && defined(_sigargs) /* Irix 5.x, not 6.x */ \ + || defined(HPUX) || defined(HURD) || defined(NETBSD) \ + || defined(FREEBSD) + /* Under Irix 5.x or HP/UX, we may get SIGBUS. */ + /* Pthreads doesn't exist under Irix 5.x, so we */ + /* don't have to worry in the threads case. */ + (void) sigaction(SIGBUS, &act, &old_bus_act); +# endif +# endif /* GC_IRIX_THREADS */ +# else + old_segv_handler = signal(SIGSEGV, h); +# ifdef SIGBUS + old_bus_handler = signal(SIGBUS, h); +# endif +# endif + } +# endif /* NEED_FIND_LIMIT || UNIX_LIKE */ + +# if defined(NEED_FIND_LIMIT) \ + || (defined(USE_PROC_FOR_LIBRARIES) && defined(THREADS)) + /* Some tools to implement HEURISTIC2 */ +# define MIN_PAGE_SIZE 256 /* Smallest conceivable page size, bytes */ + + /*ARGSUSED*/ + STATIC void GC_fault_handler(int sig) + { + LONGJMP(GC_jmp_buf, 1); + } + + GC_INNER void GC_setup_temporary_fault_handler(void) + { + /* Handler is process-wide, so this should only happen in */ + /* one thread at a time. */ + GC_ASSERT(I_HOLD_LOCK()); + GC_set_and_save_fault_handler(GC_fault_handler); + } + + GC_INNER void GC_reset_fault_handler(void) + { +# if defined(SUNOS5SIGS) || defined(IRIX5) \ + || defined(OSF1) || defined(HURD) || defined(NETBSD) + (void) sigaction(SIGSEGV, &old_segv_act, 0); +# if defined(IRIX5) && defined(_sigargs) /* Irix 5.x, not 6.x */ \ + || defined(HPUX) || defined(HURD) || defined(NETBSD) \ + || defined(FREEBSD) + (void) sigaction(SIGBUS, &old_bus_act, 0); +# endif +# else + (void) signal(SIGSEGV, old_segv_handler); +# ifdef SIGBUS + (void) signal(SIGBUS, old_bus_handler); +# endif +# endif + } + + /* Return the first non-addressable location > p (up) or */ + /* the smallest location q s.t. [q,p) is addressable (!up). */ + /* We assume that p (up) or p-1 (!up) is addressable. */ + /* Requires allocation lock. */ + STATIC ptr_t GC_find_limit_with_bound(ptr_t p, GC_bool up, ptr_t bound) + { + static volatile ptr_t result; + /* Safer if static, since otherwise it may not be */ + /* preserved across the longjmp. Can safely be */ + /* static since it's only called with the */ + /* allocation lock held. */ + + GC_ASSERT(I_HOLD_LOCK()); + GC_setup_temporary_fault_handler(); + if (SETJMP(GC_jmp_buf) == 0) { + result = (ptr_t)(((word)(p)) + & ~(MIN_PAGE_SIZE-1)); + for (;;) { + if (up) { + result += MIN_PAGE_SIZE; + if (result >= bound) { + result = bound; + break; + } + } else { + result -= MIN_PAGE_SIZE; + if (result <= bound) { + result = bound - MIN_PAGE_SIZE; + /* This is to compensate */ + /* further result increment (we */ + /* do not modify "up" variable */ + /* since it might be clobbered */ + /* by setjmp otherwise). */ + break; + } + } + GC_noop1((word)(*result)); + } + } + GC_reset_fault_handler(); + if (!up) { + result += MIN_PAGE_SIZE; + } + return(result); + } + + ptr_t GC_find_limit(ptr_t p, GC_bool up) + { + return GC_find_limit_with_bound(p, up, up ? (ptr_t)(word)(-1) : 0); + } +# endif /* NEED_FIND_LIMIT || USE_PROC_FOR_LIBRARIES */ + +#ifdef HPUX_STACKBOTTOM + +#include +#include + + GC_INNER ptr_t GC_get_register_stack_base(void) + { + struct pst_vm_status vm_status; + + int i = 0; + while (pstat_getprocvm(&vm_status, sizeof(vm_status), 0, i++) == 1) { + if (vm_status.pst_type == PS_RSESTACK) { + return (ptr_t) vm_status.pst_vaddr; + } + } + + /* old way to get the register stackbottom */ + return (ptr_t)(((word)GC_stackbottom - BACKING_STORE_DISPLACEMENT - 1) + & ~(BACKING_STORE_ALIGNMENT - 1)); + } + +#endif /* HPUX_STACK_BOTTOM */ + +#ifdef LINUX_STACKBOTTOM + +# include +# include + +# define STAT_SKIP 27 /* Number of fields preceding startstack */ + /* field in /proc/self/stat */ + +# ifdef USE_LIBC_PRIVATES +# pragma weak __libc_stack_end + extern ptr_t __libc_stack_end; +# endif + +# ifdef IA64 +# ifdef USE_LIBC_PRIVATES +# pragma weak __libc_ia64_register_backing_store_base + extern ptr_t __libc_ia64_register_backing_store_base; +# endif + + GC_INNER ptr_t GC_get_register_stack_base(void) + { + ptr_t result; + +# ifdef USE_LIBC_PRIVATES + if (0 != &__libc_ia64_register_backing_store_base + && 0 != __libc_ia64_register_backing_store_base) { + /* Glibc 2.2.4 has a bug such that for dynamically linked */ + /* executables __libc_ia64_register_backing_store_base is */ + /* defined but uninitialized during constructor calls. */ + /* Hence we check for both nonzero address and value. */ + return __libc_ia64_register_backing_store_base; + } +# endif + result = backing_store_base_from_proc(); + if (0 == result) { + result = GC_find_limit(GC_save_regs_in_stack(), FALSE); + /* Now seems to work better than constant displacement */ + /* heuristic used in 6.X versions. The latter seems to */ + /* fail for 2.6 kernels. */ + } + return result; + } +# endif /* IA64 */ + + STATIC ptr_t GC_linux_main_stack_base(void) + { + /* We read the stack base value from /proc/self/stat. We do this */ + /* using direct I/O system calls in order to avoid calling malloc */ + /* in case REDIRECT_MALLOC is defined. */ +# ifndef STAT_READ + /* Also defined in pthread_support.c. */ +# define STAT_BUF_SIZE 4096 +# define STAT_READ read +# endif + /* Should probably call the real read, if read is wrapped. */ + char stat_buf[STAT_BUF_SIZE]; + int f; + word result; + int i, buf_offset = 0, len; + + /* First try the easy way. This should work for glibc 2.2 */ + /* This fails in a prelinked ("prelink" command) executable */ + /* since the correct value of __libc_stack_end never */ + /* becomes visible to us. The second test works around */ + /* this. */ +# ifdef USE_LIBC_PRIVATES + if (0 != &__libc_stack_end && 0 != __libc_stack_end ) { +# if defined(IA64) + /* Some versions of glibc set the address 16 bytes too */ + /* low while the initialization code is running. */ + if (((word)__libc_stack_end & 0xfff) + 0x10 < 0x1000) { + return __libc_stack_end + 0x10; + } /* Otherwise it's not safe to add 16 bytes and we fall */ + /* back to using /proc. */ +# elif defined(SPARC) + /* Older versions of glibc for 64-bit Sparc do not set + * this variable correctly, it gets set to either zero + * or one. + */ + if (__libc_stack_end != (ptr_t) (unsigned long)0x1) + return __libc_stack_end; +# else + return __libc_stack_end; +# endif + } +# endif + f = open("/proc/self/stat", O_RDONLY); + if (f < 0) + ABORT("Couldn't read /proc/self/stat"); + len = STAT_READ(f, stat_buf, STAT_BUF_SIZE); + close(f); + + /* Skip the required number of fields. This number is hopefully */ + /* constant across all Linux implementations. */ + for (i = 0; i < STAT_SKIP; ++i) { + while (buf_offset < len && isspace(stat_buf[buf_offset++])) { + /* empty */ + } + while (buf_offset < len && !isspace(stat_buf[buf_offset++])) { + /* empty */ + } + } + /* Skip spaces. */ + while (buf_offset < len && isspace(stat_buf[buf_offset])) { + buf_offset++; + } + /* Find the end of the number and cut the buffer there. */ + for (i = 0; buf_offset + i < len; i++) { + if (!isdigit(stat_buf[buf_offset + i])) break; + } + if (buf_offset + i >= len) ABORT("Could not parse /proc/self/stat"); + stat_buf[buf_offset + i] = '\0'; + + result = (word)STRTOULL(&stat_buf[buf_offset], NULL, 10); + if (result < 0x100000 || (result & (sizeof(word) - 1)) != 0) + ABORT("Absurd stack bottom value"); + return (ptr_t)result; + } +#endif /* LINUX_STACKBOTTOM */ + +#ifdef FREEBSD_STACKBOTTOM + /* This uses an undocumented sysctl call, but at least one expert */ + /* believes it will stay. */ + +# include +# include +# include + + STATIC ptr_t GC_freebsd_main_stack_base(void) + { + int nm[2] = {CTL_KERN, KERN_USRSTACK}; + ptr_t base; + size_t len = sizeof(ptr_t); + int r = sysctl(nm, 2, &base, &len, NULL, 0); + if (r) ABORT("Error getting main stack base"); + return base; + } +#endif /* FREEBSD_STACKBOTTOM */ + +#if defined(ECOS) || defined(NOSYS) + ptr_t GC_get_main_stack_base(void) + { + return STACKBOTTOM; + } +# define GET_MAIN_STACKBASE_SPECIAL +#elif !defined(BEOS) && !defined(AMIGA) && !defined(OS2) \ + && !defined(MSWIN32) && !defined(MSWINCE) && !defined(CYGWIN32) \ + && !defined(GC_OPENBSD_THREADS) \ + && (!defined(GC_SOLARIS_THREADS) || defined(_STRICT_STDC)) + +# if defined(LINUX) && defined(USE_GET_STACKBASE_FOR_MAIN) +# include +# elif defined(DARWIN) && !defined(NO_PTHREAD_GET_STACKADDR_NP) + /* We could use pthread_get_stackaddr_np even in case of a */ + /* single-threaded gclib (there is no -lpthread on Darwin). */ +# include +# undef STACKBOTTOM +# define STACKBOTTOM (ptr_t)pthread_get_stackaddr_np(pthread_self()) +# endif + + ptr_t GC_get_main_stack_base(void) + { + ptr_t result; +# if defined(LINUX) && !defined(NACL) \ + && (defined(USE_GET_STACKBASE_FOR_MAIN) \ + || (defined(THREADS) && !defined(REDIRECT_MALLOC))) + pthread_attr_t attr; + void *stackaddr; + size_t size; + + if (pthread_getattr_np(pthread_self(), &attr) == 0) { + if (pthread_attr_getstack(&attr, &stackaddr, &size) == 0 + && stackaddr != NULL) { + pthread_attr_destroy(&attr); +# ifdef STACK_GROWS_DOWN + stackaddr = (char *)stackaddr + size; +# endif + return (ptr_t)stackaddr; + } + pthread_attr_destroy(&attr); + } + WARN("pthread_getattr_np or pthread_attr_getstack failed" + " for main thread\n", 0); +# endif +# ifdef STACKBOTTOM + result = STACKBOTTOM; +# else +# define STACKBOTTOM_ALIGNMENT_M1 ((word)STACK_GRAN - 1) +# ifdef HEURISTIC1 +# ifdef STACK_GROWS_DOWN + result = (ptr_t)(((word)GC_approx_sp() + STACKBOTTOM_ALIGNMENT_M1) + & ~STACKBOTTOM_ALIGNMENT_M1); +# else + result = (ptr_t)((word)GC_approx_sp() & ~STACKBOTTOM_ALIGNMENT_M1); +# endif +# endif /* HEURISTIC1 */ +# ifdef LINUX_STACKBOTTOM + result = GC_linux_main_stack_base(); +# endif +# ifdef FREEBSD_STACKBOTTOM + result = GC_freebsd_main_stack_base(); +# endif +# ifdef HEURISTIC2 + { + ptr_t sp = GC_approx_sp(); +# ifdef STACK_GROWS_DOWN + result = GC_find_limit(sp, TRUE); +# ifdef HEURISTIC2_LIMIT + if (result > HEURISTIC2_LIMIT + && sp < HEURISTIC2_LIMIT) { + result = HEURISTIC2_LIMIT; + } +# endif +# else + result = GC_find_limit(sp, FALSE); +# ifdef HEURISTIC2_LIMIT + if (result < HEURISTIC2_LIMIT + && sp > HEURISTIC2_LIMIT) { + result = HEURISTIC2_LIMIT; + } +# endif +# endif + } +# endif /* HEURISTIC2 */ +# ifdef STACK_GROWS_DOWN + if (result == 0) + result = (ptr_t)(signed_word)(-sizeof(ptr_t)); +# endif +# endif + GC_ASSERT(GC_approx_sp() HOTTER_THAN result); + return(result); + } +# define GET_MAIN_STACKBASE_SPECIAL +#endif /* !AMIGA, !BEOS, !OPENBSD, !OS2, !Windows */ + +#if (defined(GC_LINUX_THREADS) || defined(PLATFORM_ANDROID)) && !defined(NACL) + +# include + /* extern int pthread_getattr_np(pthread_t, pthread_attr_t *); */ + + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b) + { + pthread_attr_t attr; + size_t size; +# ifdef IA64 + DCL_LOCK_STATE; +# endif + + if (pthread_getattr_np(pthread_self(), &attr) != 0) { + WARN("pthread_getattr_np failed\n", 0); + return GC_UNIMPLEMENTED; + } + if (pthread_attr_getstack(&attr, &(b -> mem_base), &size) != 0) { + ABORT("pthread_attr_getstack failed"); + } + pthread_attr_destroy(&attr); +# ifdef STACK_GROWS_DOWN + b -> mem_base = (char *)(b -> mem_base) + size; +# endif +# ifdef IA64 + /* We could try backing_store_base_from_proc, but that's safe */ + /* only if no mappings are being asynchronously created. */ + /* Subtracting the size from the stack base doesn't work for at */ + /* least the main thread. */ + LOCK(); + { + IF_CANCEL(int cancel_state;) + ptr_t bsp; + ptr_t next_stack; + + DISABLE_CANCEL(cancel_state); + bsp = GC_save_regs_in_stack(); + next_stack = GC_greatest_stack_base_below(bsp); + if (0 == next_stack) { + b -> reg_base = GC_find_limit(bsp, FALSE); + } else { + /* Avoid walking backwards into preceding memory stack and */ + /* growing it. */ + b -> reg_base = GC_find_limit_with_bound(bsp, FALSE, next_stack); + } + RESTORE_CANCEL(cancel_state); + } + UNLOCK(); +# endif + return GC_SUCCESS; + } +# define HAVE_GET_STACK_BASE +#endif /* GC_LINUX_THREADS */ + +#if defined(GC_DARWIN_THREADS) && !defined(NO_PTHREAD_GET_STACKADDR_NP) +# include + + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b) + { + /* pthread_get_stackaddr_np() should return stack bottom (highest */ + /* stack address plus 1). */ + b->mem_base = pthread_get_stackaddr_np(pthread_self()); + GC_ASSERT((void *)GC_approx_sp() HOTTER_THAN b->mem_base); + return GC_SUCCESS; + } +# define HAVE_GET_STACK_BASE +#endif /* GC_DARWIN_THREADS */ + +#ifdef GC_OPENBSD_THREADS +# include +# include +# include + + /* Find the stack using pthread_stackseg_np(). */ + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb) + { + stack_t stack; + if (pthread_stackseg_np(pthread_self(), &stack)) + ABORT("pthread_stackseg_np(self) failed"); + sb->mem_base = stack.ss_sp; + return GC_SUCCESS; + } +# define HAVE_GET_STACK_BASE +#endif /* GC_OPENBSD_THREADS */ + +#if defined(GC_SOLARIS_THREADS) && !defined(_STRICT_STDC) + +# include +# include +# include + + /* These variables are used to cache ss_sp value for the primordial */ + /* thread (it's better not to call thr_stksegment() twice for this */ + /* thread - see JDK bug #4352906). */ + static pthread_t stackbase_main_self = 0; + /* 0 means stackbase_main_ss_sp value is unset. */ + static void *stackbase_main_ss_sp = NULL; + + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b) + { + stack_t s; + pthread_t self = pthread_self(); + + if (self == stackbase_main_self) + { + /* If the client calls GC_get_stack_base() from the main thread */ + /* then just return the cached value. */ + b -> mem_base = stackbase_main_ss_sp; + GC_ASSERT(b -> mem_base != NULL); + return GC_SUCCESS; + } + + if (thr_stksegment(&s)) { + /* According to the manual, the only failure error code returned */ + /* is EAGAIN meaning "the information is not available due to the */ + /* thread is not yet completely initialized or it is an internal */ + /* thread" - this shouldn't happen here. */ + ABORT("thr_stksegment failed"); + } + /* s.ss_sp holds the pointer to the stack bottom. */ + GC_ASSERT((void *)GC_approx_sp() HOTTER_THAN s.ss_sp); + + if (!stackbase_main_self && thr_main() != 0) + { + /* Cache the stack base value for the primordial thread (this */ + /* is done during GC_init, so there is no race). */ + stackbase_main_ss_sp = s.ss_sp; + stackbase_main_self = self; + } + + b -> mem_base = s.ss_sp; + return GC_SUCCESS; + } +# define HAVE_GET_STACK_BASE +#endif /* GC_SOLARIS_THREADS */ + +#ifdef GC_RTEMS_PTHREADS + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb) + { + sb->mem_base = rtems_get_stack_bottom(); + return GC_SUCCESS; + } +# define HAVE_GET_STACK_BASE +#endif /* GC_RTEMS_PTHREADS */ + +#ifndef HAVE_GET_STACK_BASE + /* Retrieve stack base. */ + /* Using the GC_find_limit version is risky. */ + /* On IA64, for example, there is no guard page between the */ + /* stack of one thread and the register backing store of the */ + /* next. Thus this is likely to identify way too large a */ + /* "stack" and thus at least result in disastrous performance. */ + /* FIXME - Implement better strategies here. */ + GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b) + { +# ifdef NEED_FIND_LIMIT + IF_CANCEL(int cancel_state;) + DCL_LOCK_STATE; + + LOCK(); + DISABLE_CANCEL(cancel_state); /* May be unnecessary? */ +# ifdef STACK_GROWS_DOWN + b -> mem_base = GC_find_limit(GC_approx_sp(), TRUE); +# ifdef IA64 + b -> reg_base = GC_find_limit(GC_save_regs_in_stack(), FALSE); +# endif +# else + b -> mem_base = GC_find_limit(GC_approx_sp(), FALSE); +# endif + RESTORE_CANCEL(cancel_state); + UNLOCK(); + return GC_SUCCESS; +# else + return GC_UNIMPLEMENTED; +# endif + } +#endif /* !HAVE_GET_STACK_BASE */ + +#ifndef GET_MAIN_STACKBASE_SPECIAL + /* This is always called from the main thread. Default implementation. */ + ptr_t GC_get_main_stack_base(void) + { + struct GC_stack_base sb; + + if (GC_get_stack_base(&sb) != GC_SUCCESS) + ABORT("GC_get_stack_base failed"); + GC_ASSERT((void *)GC_approx_sp() HOTTER_THAN sb.mem_base); + return (ptr_t)sb.mem_base; + } +#endif /* !GET_MAIN_STACKBASE_SPECIAL */ + +/* Register static data segment(s) as roots. If more data segments are */ +/* added later then they need to be registered at that point (as we do */ +/* with SunOS dynamic loading), or GC_mark_roots needs to check for */ +/* them (as we do with PCR). Called with allocator lock held. */ +# ifdef OS2 + +void GC_register_data_segments(void) +{ + PTIB ptib; + PPIB ppib; + HMODULE module_handle; +# define PBUFSIZ 512 + UCHAR path[PBUFSIZ]; + FILE * myexefile; + struct exe_hdr hdrdos; /* MSDOS header. */ + struct e32_exe hdr386; /* Real header for my executable */ + struct o32_obj seg; /* Currrent segment */ + int nsegs; + + + if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) { + ABORT("DosGetInfoBlocks failed"); + } + module_handle = ppib -> pib_hmte; + if (DosQueryModuleName(module_handle, PBUFSIZ, path) != NO_ERROR) { + GC_err_printf("DosQueryModuleName failed\n"); + ABORT("DosGetInfoBlocks failed"); + } + myexefile = fopen(path, "rb"); + if (myexefile == 0) { + if (GC_print_stats) { + GC_err_puts("Couldn't open executable "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Failed to open executable"); + } + if (fread((char *)(&hdrdos), 1, sizeof(hdrdos), myexefile) + < sizeof(hdrdos)) { + if (GC_print_stats) { + GC_err_puts("Couldn't read MSDOS header from "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Couldn't read MSDOS header"); + } + if (E_MAGIC(hdrdos) != EMAGIC) { + if (GC_print_stats) { + GC_err_puts("Executable has wrong DOS magic number: "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Bad DOS magic number"); + } + if (fseek(myexefile, E_LFANEW(hdrdos), SEEK_SET) != 0) { + if (GC_print_stats) { + GC_err_puts("Seek to new header failed in "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Bad DOS magic number"); + } + if (fread((char *)(&hdr386), 1, sizeof(hdr386), myexefile) + < sizeof(hdr386)) { + if (GC_print_stats) { + GC_err_puts("Couldn't read MSDOS header from "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Couldn't read OS/2 header"); + } + if (E32_MAGIC1(hdr386) != E32MAGIC1 || E32_MAGIC2(hdr386) != E32MAGIC2) { + if (GC_print_stats) { + GC_err_puts("Executable has wrong OS/2 magic number: "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Bad OS/2 magic number"); + } + if (E32_BORDER(hdr386) != E32LEBO || E32_WORDER(hdr386) != E32LEWO) { + if (GC_print_stats) { + GC_err_puts("Executable has wrong byte order: "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Bad byte order"); + } + if (E32_CPU(hdr386) == E32CPU286) { + if (GC_print_stats) { + GC_err_puts("GC can't handle 80286 executables: "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Intel 80286 executables are unsupported"); + } + if (fseek(myexefile, E_LFANEW(hdrdos) + E32_OBJTAB(hdr386), + SEEK_SET) != 0) { + if (GC_print_stats) { + GC_err_puts("Seek to object table failed: "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Seek to object table failed"); + } + for (nsegs = E32_OBJCNT(hdr386); nsegs > 0; nsegs--) { + int flags; + if (fread((char *)(&seg), 1, sizeof(seg), myexefile) < sizeof(seg)) { + if (GC_print_stats) { + GC_err_puts("Couldn't read obj table entry from "); + GC_err_puts(path); + GC_err_puts("\n"); + } + ABORT("Couldn't read obj table entry"); + } + flags = O32_FLAGS(seg); + if (!(flags & OBJWRITE)) continue; + if (!(flags & OBJREAD)) continue; + if (flags & OBJINVALID) { + GC_err_printf("Object with invalid pages?\n"); + continue; + } + GC_add_roots_inner((ptr_t)O32_BASE(seg), + (ptr_t)(O32_BASE(seg)+O32_SIZE(seg)), FALSE); + } +} + +# else /* !OS2 */ + +# if defined(GWW_VDB) +# ifndef MEM_WRITE_WATCH +# define MEM_WRITE_WATCH 0x200000 +# endif +# ifndef WRITE_WATCH_FLAG_RESET +# define WRITE_WATCH_FLAG_RESET 1 +# endif + + /* Since we can't easily check whether ULONG_PTR and SIZE_T are */ + /* defined in Win32 basetsd.h, we define own ULONG_PTR. */ +# define GC_ULONG_PTR word + + typedef UINT (WINAPI * GetWriteWatch_type)( + DWORD, PVOID, GC_ULONG_PTR /* SIZE_T */, + PVOID *, GC_ULONG_PTR *, PULONG); + static GetWriteWatch_type GetWriteWatch_func; + static DWORD GetWriteWatch_alloc_flag; + +# define GC_GWW_AVAILABLE() (GetWriteWatch_func != NULL) + + static void detect_GetWriteWatch(void) + { + static GC_bool done; + HMODULE hK32; + if (done) + return; + +# if defined(MPROTECT_VDB) + { + char * str = GETENV("GC_USE_GETWRITEWATCH"); +# if defined(GC_PREFER_MPROTECT_VDB) + if (str == NULL || (*str == '0' && *(str + 1) == '\0')) { + /* GC_USE_GETWRITEWATCH is unset or set to "0". */ + done = TRUE; /* falling back to MPROTECT_VDB strategy. */ + /* This should work as if GWW_VDB is undefined. */ + return; + } +# else + if (str != NULL && *str == '0' && *(str + 1) == '\0') { + /* GC_USE_GETWRITEWATCH is set "0". */ + done = TRUE; /* falling back to MPROTECT_VDB strategy. */ + return; + } +# endif + } +# endif + + hK32 = GetModuleHandle(TEXT("kernel32.dll")); + if (hK32 != (HMODULE)0 && + (GetWriteWatch_func = (GetWriteWatch_type)GetProcAddress(hK32, + "GetWriteWatch")) != NULL) { + /* Also check whether VirtualAlloc accepts MEM_WRITE_WATCH, */ + /* as some versions of kernel32.dll have one but not the */ + /* other, making the feature completely broken. */ + void * page = VirtualAlloc(NULL, GC_page_size, + MEM_WRITE_WATCH | MEM_RESERVE, + PAGE_READWRITE); + if (page != NULL) { + PVOID pages[16]; + GC_ULONG_PTR count = 16; + DWORD page_size; + /* Check that it actually works. In spite of some */ + /* documentation it actually seems to exist on W2K. */ + /* This test may be unnecessary, but ... */ + if (GetWriteWatch_func(WRITE_WATCH_FLAG_RESET, + page, GC_page_size, + pages, + &count, + &page_size) != 0) { + /* GetWriteWatch always fails. */ + GetWriteWatch_func = NULL; + } else { + GetWriteWatch_alloc_flag = MEM_WRITE_WATCH; + } + VirtualFree(page, GC_page_size, MEM_RELEASE); + } else { + /* GetWriteWatch will be useless. */ + GetWriteWatch_func = NULL; + } + } + if (GC_print_stats) { + if (GetWriteWatch_func == NULL) { + GC_log_printf("Did not find a usable GetWriteWatch()\n"); + } else { + GC_log_printf("Using GetWriteWatch()\n"); + } + } + done = TRUE; + } + +# else +# define GetWriteWatch_alloc_flag 0 +# endif /* !GWW_VDB */ + +# if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32) + +# ifdef MSWIN32 + /* Unfortunately, we have to handle win32s very differently from NT, */ + /* Since VirtualQuery has very different semantics. In particular, */ + /* under win32s a VirtualQuery call on an unmapped page returns an */ + /* invalid result. Under NT, GC_register_data_segments is a no-op */ + /* and all real work is done by GC_register_dynamic_libraries. Under */ + /* win32s, we cannot find the data segments associated with dll's. */ + /* We register the main data segment here. */ + GC_INNER GC_bool GC_no_win32_dlls = FALSE; + /* This used to be set for gcc, to avoid dealing with */ + /* the structured exception handling issues. But we now have */ + /* assembly code to do that right. */ + + GC_INNER GC_bool GC_wnt = FALSE; + /* This is a Windows NT derivative, i.e. NT, W2K, XP or later. */ + + GC_INNER void GC_init_win32(void) + { + /* Set GC_wnt. If we're running under win32s, assume that no DLLs */ + /* will be loaded. I doubt anyone still runs win32s, but... */ + DWORD v = GetVersion(); + GC_wnt = !(v & 0x80000000); + GC_no_win32_dlls |= ((!GC_wnt) && (v & 0xff) <= 3); +# ifdef USE_MUNMAP + if (GC_no_win32_dlls) { + /* Turn off unmapping for safety (since may not work well with */ + /* GlobalAlloc). */ + GC_unmap_threshold = 0; + } +# endif + } + + /* Return the smallest address a such that VirtualQuery */ + /* returns correct results for all addresses between a and start. */ + /* Assumes VirtualQuery returns correct information for start. */ + STATIC ptr_t GC_least_described_address(ptr_t start) + { + MEMORY_BASIC_INFORMATION buf; + size_t result; + LPVOID limit; + ptr_t p; + LPVOID q; + + limit = GC_sysinfo.lpMinimumApplicationAddress; + p = (ptr_t)((word)start & ~(GC_page_size - 1)); + for (;;) { + q = (LPVOID)(p - GC_page_size); + if ((ptr_t)q > (ptr_t)p /* underflow */ || q < limit) break; + result = VirtualQuery(q, &buf, sizeof(buf)); + if (result != sizeof(buf) || buf.AllocationBase == 0) break; + p = (ptr_t)(buf.AllocationBase); + } + return p; + } +# endif /* MSWIN32 */ + +# ifndef REDIRECT_MALLOC + /* We maintain a linked list of AllocationBase values that we know */ + /* correspond to malloc heap sections. Currently this is only called */ + /* during a GC. But there is some hope that for long running */ + /* programs we will eventually see most heap sections. */ + + /* In the long run, it would be more reliable to occasionally walk */ + /* the malloc heap with HeapWalk on the default heap. But that */ + /* apparently works only for NT-based Windows. */ + + STATIC size_t GC_max_root_size = 100000; /* Appr. largest root size. */ + +# ifndef CYGWIN32 + /* In the long run, a better data structure would also be nice ... */ + STATIC struct GC_malloc_heap_list { + void * allocation_base; + struct GC_malloc_heap_list *next; + } *GC_malloc_heap_l = 0; + + /* Is p the base of one of the malloc heap sections we already know */ + /* about? */ + STATIC GC_bool GC_is_malloc_heap_base(ptr_t p) + { + struct GC_malloc_heap_list *q = GC_malloc_heap_l; + + while (0 != q) { + if (q -> allocation_base == p) return TRUE; + q = q -> next; + } + return FALSE; + } + + STATIC void *GC_get_allocation_base(void *p) + { + MEMORY_BASIC_INFORMATION buf; + size_t result = VirtualQuery(p, &buf, sizeof(buf)); + if (result != sizeof(buf)) { + ABORT("Weird VirtualQuery result"); + } + return buf.AllocationBase; + } + + GC_INNER void GC_add_current_malloc_heap(void) + { + struct GC_malloc_heap_list *new_l = + malloc(sizeof(struct GC_malloc_heap_list)); + void * candidate = GC_get_allocation_base(new_l); + + if (new_l == 0) return; + if (GC_is_malloc_heap_base(candidate)) { + /* Try a little harder to find malloc heap. */ + size_t req_size = 10000; + do { + void *p = malloc(req_size); + if (0 == p) { + free(new_l); + return; + } + candidate = GC_get_allocation_base(p); + free(p); + req_size *= 2; + } while (GC_is_malloc_heap_base(candidate) + && req_size < GC_max_root_size/10 && req_size < 500000); + if (GC_is_malloc_heap_base(candidate)) { + free(new_l); + return; + } + } + if (GC_print_stats) + GC_log_printf("Found new system malloc AllocationBase at %p\n", + candidate); + new_l -> allocation_base = candidate; + new_l -> next = GC_malloc_heap_l; + GC_malloc_heap_l = new_l; + } +# endif /* !CYGWIN32 */ + +# endif /* !REDIRECT_MALLOC */ + + STATIC word GC_n_heap_bases = 0; /* See GC_heap_bases. */ + + /* Is p the start of either the malloc heap, or of one of our */ + /* heap sections? */ + GC_INNER GC_bool GC_is_heap_base(ptr_t p) + { + unsigned i; +# ifndef REDIRECT_MALLOC + if (GC_root_size > GC_max_root_size) GC_max_root_size = GC_root_size; +# ifndef CYGWIN32 + if (GC_is_malloc_heap_base(p)) return TRUE; +# endif +# endif + for (i = 0; i < GC_n_heap_bases; i++) { + if (GC_heap_bases[i] == p) return TRUE; + } + return FALSE; + } + +#ifdef MSWIN32 + STATIC void GC_register_root_section(ptr_t static_root) + { + MEMORY_BASIC_INFORMATION buf; + size_t result; + DWORD protect; + LPVOID p; + char * base; + char * limit, * new_limit; + + if (!GC_no_win32_dlls) return; + p = base = limit = GC_least_described_address(static_root); + while (p < GC_sysinfo.lpMaximumApplicationAddress) { + result = VirtualQuery(p, &buf, sizeof(buf)); + if (result != sizeof(buf) || buf.AllocationBase == 0 + || GC_is_heap_base(buf.AllocationBase)) break; + new_limit = (char *)p + buf.RegionSize; + protect = buf.Protect; + if (buf.State == MEM_COMMIT + && is_writable(protect)) { + if ((char *)p == limit) { + limit = new_limit; + } else { + if (base != limit) GC_add_roots_inner(base, limit, FALSE); + base = p; + limit = new_limit; + } + } + if (p > (LPVOID)new_limit /* overflow */) break; + p = (LPVOID)new_limit; + } + if (base != limit) GC_add_roots_inner(base, limit, FALSE); + } +#endif /* MSWIN32 */ + + void GC_register_data_segments(void) + { +# ifdef MSWIN32 + GC_register_root_section((ptr_t)&GC_pages_executable); + /* any other GC global variable would fit too. */ +# endif + } + +# else /* !OS2 && !Windows */ + +# if (defined(SVR4) || defined(AUX) || defined(DGUX) \ + || (defined(LINUX) && defined(SPARC))) && !defined(PCR) + ptr_t GC_SysVGetDataStart(size_t max_page_size, ptr_t etext_addr) + { + word text_end = ((word)(etext_addr) + sizeof(word) - 1) + & ~(sizeof(word) - 1); + /* etext rounded to word boundary */ + word next_page = ((text_end + (word)max_page_size - 1) + & ~((word)max_page_size - 1)); + word page_offset = (text_end & ((word)max_page_size - 1)); + char * volatile result = (char *)(next_page + page_offset); + /* Note that this isn't equivalent to just adding */ + /* max_page_size to &etext if &etext is at a page boundary */ + + GC_setup_temporary_fault_handler(); + if (SETJMP(GC_jmp_buf) == 0) { + /* Try writing to the address. */ + *result = *result; + GC_reset_fault_handler(); + } else { + GC_reset_fault_handler(); + /* We got here via a longjmp. The address is not readable. */ + /* This is known to happen under Solaris 2.4 + gcc, which place */ + /* string constants in the text segment, but after etext. */ + /* Use plan B. Note that we now know there is a gap between */ + /* text and data segments, so plan A bought us something. */ + result = (char *)GC_find_limit((ptr_t)(DATAEND), FALSE); + } + return((ptr_t)result); + } +# endif + +# if defined(FREEBSD) && !defined(PCR) && (defined(I386) || defined(X86_64) \ + || defined(powerpc) || defined(__powerpc__)) + +/* Its unclear whether this should be identical to the above, or */ +/* whether it should apply to non-X86 architectures. */ +/* For now we don't assume that there is always an empty page after */ +/* etext. But in some cases there actually seems to be slightly more. */ +/* This also deals with holes between read-only data and writable data. */ +ptr_t GC_FreeBSDGetDataStart(size_t max_page_size, ptr_t etext_addr) +{ + word text_end = ((word)(etext_addr) + sizeof(word) - 1) + & ~(sizeof(word) - 1); + /* etext rounded to word boundary */ + volatile word next_page = (text_end + (word)max_page_size - 1) + & ~((word)max_page_size - 1); + volatile ptr_t result = (ptr_t)text_end; + GC_setup_temporary_fault_handler(); + if (SETJMP(GC_jmp_buf) == 0) { + /* Try reading at the address. */ + /* This should happen before there is another thread. */ + for (; next_page < (word)(DATAEND); next_page += (word)max_page_size) + *(volatile char *)next_page; + GC_reset_fault_handler(); + } else { + GC_reset_fault_handler(); + /* As above, we go to plan B */ + result = GC_find_limit((ptr_t)(DATAEND), FALSE); + } + return(result); +} + +# endif /* FREEBSD */ + + +#ifdef AMIGA + +# define GC_AMIGA_DS +# include "extra/AmigaOS.c" +# undef GC_AMIGA_DS + +#elif defined(OPENBSD) + +/* Depending on arch alignment, there can be multiple holes */ +/* between DATASTART and DATAEND. Scan in DATASTART .. DATAEND */ +/* and register each region. */ +void GC_register_data_segments(void) +{ + ptr_t region_start = DATASTART; + ptr_t region_end; + + for (;;) { + region_end = GC_find_limit_openbsd(region_start, DATAEND); + GC_add_roots_inner(region_start, region_end, FALSE); + if (region_end >= DATAEND) + break; + region_start = GC_skip_hole_openbsd(region_end, DATAEND); + } +} + +# else /* !OS2 && !Windows && !AMIGA && !OPENBSD */ + +void GC_register_data_segments(void) +{ +# if !defined(PCR) && !defined(MACOS) +# if defined(REDIRECT_MALLOC) && defined(GC_SOLARIS_THREADS) + /* As of Solaris 2.3, the Solaris threads implementation */ + /* allocates the data structure for the initial thread with */ + /* sbrk at process startup. It needs to be scanned, so that */ + /* we don't lose some malloc allocated data structures */ + /* hanging from it. We're on thin ice here ... */ + extern caddr_t sbrk(int); + + GC_add_roots_inner(DATASTART, (ptr_t)sbrk(0), FALSE); +# else + GC_add_roots_inner(DATASTART, (ptr_t)(DATAEND), FALSE); +# if defined(DATASTART2) + GC_add_roots_inner(DATASTART2, (ptr_t)(DATAEND2), FALSE); +# endif +# endif +# endif +# if defined(MACOS) + { +# if defined(THINK_C) + extern void* GC_MacGetDataStart(void); + /* globals begin above stack and end at a5. */ + GC_add_roots_inner((ptr_t)GC_MacGetDataStart(), + (ptr_t)LMGetCurrentA5(), FALSE); +# else +# if defined(__MWERKS__) +# if !__POWERPC__ + extern void* GC_MacGetDataStart(void); + /* MATTHEW: Function to handle Far Globals (CW Pro 3) */ +# if __option(far_data) + extern void* GC_MacGetDataEnd(void); +# endif + /* globals begin above stack and end at a5. */ + GC_add_roots_inner((ptr_t)GC_MacGetDataStart(), + (ptr_t)LMGetCurrentA5(), FALSE); + /* MATTHEW: Handle Far Globals */ +# if __option(far_data) + /* Far globals follow he QD globals: */ + GC_add_roots_inner((ptr_t)LMGetCurrentA5(), + (ptr_t)GC_MacGetDataEnd(), FALSE); +# endif +# else + extern char __data_start__[], __data_end__[]; + GC_add_roots_inner((ptr_t)&__data_start__, + (ptr_t)&__data_end__, FALSE); +# endif /* __POWERPC__ */ +# endif /* __MWERKS__ */ +# endif /* !THINK_C */ + } +# endif /* MACOS */ + + /* Dynamic libraries are added at every collection, since they may */ + /* change. */ +} + +# endif /* ! AMIGA */ +# endif /* ! MSWIN32 && ! MSWINCE*/ +# endif /* ! OS2 */ + +/* + * Auxiliary routines for obtaining memory from OS. + */ + +# if !defined(OS2) && !defined(PCR) && !defined(AMIGA) && !defined(MSWIN32) \ + && !defined(MSWINCE) && !defined(MACOS) && !defined(DOS4GW) \ + && !defined(NONSTOP) && !defined(SN_TARGET_PS3) && !defined(RTEMS) \ + && !defined(__CC_ARM) + +# define SBRK_ARG_T ptrdiff_t + +#if defined(MMAP_SUPPORTED) + +#ifdef USE_MMAP_FIXED +# define GC_MMAP_FLAGS MAP_FIXED | MAP_PRIVATE + /* Seems to yield better performance on Solaris 2, but can */ + /* be unreliable if something is already mapped at the address. */ +#else +# define GC_MMAP_FLAGS MAP_PRIVATE +#endif + +#ifdef USE_MMAP_ANON +# define zero_fd -1 +# if defined(MAP_ANONYMOUS) +# define OPT_MAP_ANON MAP_ANONYMOUS +# else +# define OPT_MAP_ANON MAP_ANON +# endif +#else + static int zero_fd; +# define OPT_MAP_ANON 0 +#endif + +#ifndef HEAP_START +# define HEAP_START ((ptr_t)0) +#endif + +STATIC ptr_t GC_unix_mmap_get_mem(word bytes) +{ + void *result; + static ptr_t last_addr = HEAP_START; + +# ifndef USE_MMAP_ANON + static GC_bool initialized = FALSE; + + if (!initialized) { + zero_fd = open("/dev/zero", O_RDONLY); + fcntl(zero_fd, F_SETFD, FD_CLOEXEC); + initialized = TRUE; + } +# endif + + if (bytes & (GC_page_size - 1)) ABORT("Bad GET_MEM arg"); + result = mmap(last_addr, bytes, (PROT_READ | PROT_WRITE) + | (GC_pages_executable ? PROT_EXEC : 0), + GC_MMAP_FLAGS | OPT_MAP_ANON, zero_fd, 0/* offset */); +# undef IGNORE_PAGES_EXECUTABLE + + if (result == MAP_FAILED) return(0); + last_addr = (ptr_t)result + bytes + GC_page_size - 1; + last_addr = (ptr_t)((word)last_addr & ~(GC_page_size - 1)); +# if !defined(LINUX) + if (last_addr == 0) { + /* Oops. We got the end of the address space. This isn't */ + /* usable by arbitrary C code, since one-past-end pointers */ + /* don't work, so we discard it and try again. */ + munmap(result, (size_t)(-GC_page_size) - (size_t)result); + /* Leave last page mapped, so we can't repeat. */ + return GC_unix_mmap_get_mem(bytes); + } +# else + GC_ASSERT(last_addr != 0); +# endif + return((ptr_t)result); +} + +# endif /* MMAP_SUPPORTED */ + +#if defined(USE_MMAP) + ptr_t GC_unix_get_mem(word bytes) + { + return GC_unix_mmap_get_mem(bytes); + } +#else /* !USE_MMAP */ + +STATIC ptr_t GC_unix_sbrk_get_mem(word bytes) +{ + ptr_t result; +# ifdef IRIX5 + /* Bare sbrk isn't thread safe. Play by malloc rules. */ + /* The equivalent may be needed on other systems as well. */ + __LOCK_MALLOC(); +# endif + { + ptr_t cur_brk = (ptr_t)sbrk(0); + SBRK_ARG_T lsbs = (word)cur_brk & (GC_page_size-1); + + if ((SBRK_ARG_T)bytes < 0) { + result = 0; /* too big */ + goto out; + } + if (lsbs != 0) { + if((ptr_t)sbrk(GC_page_size - lsbs) == (ptr_t)(-1)) { + result = 0; + goto out; + } + } +# ifdef ADD_HEAP_GUARD_PAGES + /* This is useful for catching severe memory overwrite problems that */ + /* span heap sections. It shouldn't otherwise be turned on. */ + { + ptr_t guard = (ptr_t)sbrk((SBRK_ARG_T)GC_page_size); + if (mprotect(guard, GC_page_size, PROT_NONE) != 0) + ABORT("ADD_HEAP_GUARD_PAGES: mprotect failed"); + } +# endif /* ADD_HEAP_GUARD_PAGES */ + result = (ptr_t)sbrk((SBRK_ARG_T)bytes); + if (result == (ptr_t)(-1)) result = 0; + } + out: +# ifdef IRIX5 + __UNLOCK_MALLOC(); +# endif + return(result); +} + +ptr_t GC_unix_get_mem(word bytes) +{ +# if defined(MMAP_SUPPORTED) + /* By default, we try both sbrk and mmap, in that order. */ + static GC_bool sbrk_failed = FALSE; + ptr_t result = 0; + + if (!sbrk_failed) result = GC_unix_sbrk_get_mem(bytes); + if (0 == result) { + sbrk_failed = TRUE; + result = GC_unix_mmap_get_mem(bytes); + } + if (0 == result) { + /* Try sbrk again, in case sbrk memory became available. */ + result = GC_unix_sbrk_get_mem(bytes); + } + return result; +# else /* !MMAP_SUPPORTED */ + return GC_unix_sbrk_get_mem(bytes); +# endif +} + +#endif /* !USE_MMAP */ + +# endif /* UN*X */ + +# ifdef OS2 + +void * os2_alloc(size_t bytes) +{ + void * result; + + if (DosAllocMem(&result, bytes, (PAG_READ | PAG_WRITE | PAG_COMMIT) + | (GC_pages_executable ? PAG_EXECUTE : 0)) + != NO_ERROR) { + return(0); + } + /* FIXME: What's the purpose of this recursion? (Probably, if */ + /* DosAllocMem returns memory at 0 address then just retry once.) */ + if (result == 0) return(os2_alloc(bytes)); + return(result); +} + +# endif /* OS2 */ + +# if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32) + GC_INNER SYSTEM_INFO GC_sysinfo; +# endif + +#ifdef MSWIN32 + +# ifdef USE_GLOBAL_ALLOC +# define GLOBAL_ALLOC_TEST 1 +# else +# define GLOBAL_ALLOC_TEST GC_no_win32_dlls +# endif + +# ifdef GC_USE_MEM_TOP_DOWN + STATIC DWORD GC_mem_top_down = MEM_TOP_DOWN; + /* Use GC_USE_MEM_TOP_DOWN for better 64-bit */ + /* testing. Otherwise all addresses tend to */ + /* end up in first 4GB, hiding bugs. */ +# else + STATIC DWORD GC_mem_top_down = 0; +# endif + +#endif /* MSWIN32 */ + +#if defined(MSWIN32) || defined(CYGWIN32) + ptr_t GC_win32_get_mem(word bytes) + { + ptr_t result; + +# ifdef CYGWIN32 + result = GC_unix_get_mem(bytes); +# else + if (GLOBAL_ALLOC_TEST) { + /* VirtualAlloc doesn't like PAGE_EXECUTE_READWRITE. */ + /* There are also unconfirmed rumors of other */ + /* problems, so we dodge the issue. */ + result = (ptr_t) GlobalAlloc(0, bytes + HBLKSIZE); + result = (ptr_t)(((word)result + HBLKSIZE - 1) & ~(HBLKSIZE-1)); + } else { + /* VirtualProtect only works on regions returned by a */ + /* single VirtualAlloc call. Thus we allocate one */ + /* extra page, which will prevent merging of blocks */ + /* in separate regions, and eliminate any temptation */ + /* to call VirtualProtect on a range spanning regions. */ + /* This wastes a small amount of memory, and risks */ + /* increased fragmentation. But better alternatives */ + /* would require effort. */ +# ifdef MPROTECT_VDB + /* We can't check for GC_incremental here (because */ + /* GC_enable_incremental() might be called some time */ + /* later after the GC initialization). */ +# ifdef GWW_VDB +# define VIRTUAL_ALLOC_PAD (GC_GWW_AVAILABLE() ? 0 : 1) +# else +# define VIRTUAL_ALLOC_PAD 1 +# endif +# else +# define VIRTUAL_ALLOC_PAD 0 +# endif + /* Pass the MEM_WRITE_WATCH only if GetWriteWatch-based */ + /* VDBs are enabled and the GetWriteWatch function is */ + /* available. Otherwise we waste resources or possibly */ + /* cause VirtualAlloc to fail (observed in Windows 2000 */ + /* SP2). */ + result = (ptr_t) VirtualAlloc(NULL, bytes + VIRTUAL_ALLOC_PAD, + GetWriteWatch_alloc_flag + | (MEM_COMMIT | MEM_RESERVE) + | GC_mem_top_down, + GC_pages_executable ? PAGE_EXECUTE_READWRITE : + PAGE_READWRITE); +# undef IGNORE_PAGES_EXECUTABLE + } +# endif /* !CYGWIN32 */ + if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result"); + /* If I read the documentation correctly, this can */ + /* only happen if HBLKSIZE > 64k or not a power of 2. */ + if (GC_n_heap_bases >= MAX_HEAP_SECTS) ABORT("Too many heap sections"); + if (0 != result) GC_heap_bases[GC_n_heap_bases++] = result; + return(result); + } + + GC_API void GC_CALL GC_win32_free_heap(void) + { +# ifndef CYGWIN32 + if (GC_no_win32_dlls) +# endif + { + while (GC_n_heap_bases-- > 0) { +# ifdef CYGWIN32 + /* FIXME: Is it ok to use non-GC free() here? */ +# else + GlobalFree(GC_heap_bases[GC_n_heap_bases]); +# endif + GC_heap_bases[GC_n_heap_bases] = 0; + } + } + } +#endif /* MSWIN32 || CYGWIN32 */ + +#ifdef AMIGA +# define GC_AMIGA_AM +# include "extra/AmigaOS.c" +# undef GC_AMIGA_AM +#endif + + +#ifdef MSWINCE + ptr_t GC_wince_get_mem(word bytes) + { + ptr_t result = 0; /* initialized to prevent warning. */ + word i; + + /* Round up allocation size to multiple of page size */ + bytes = (bytes + GC_page_size-1) & ~(GC_page_size-1); + + /* Try to find reserved, uncommitted pages */ + for (i = 0; i < GC_n_heap_bases; i++) { + if (((word)(-(signed_word)GC_heap_lengths[i]) + & (GC_sysinfo.dwAllocationGranularity-1)) + >= bytes) { + result = GC_heap_bases[i] + GC_heap_lengths[i]; + break; + } + } + + if (i == GC_n_heap_bases) { + /* Reserve more pages */ + word res_bytes = (bytes + GC_sysinfo.dwAllocationGranularity-1) + & ~(GC_sysinfo.dwAllocationGranularity-1); + /* If we ever support MPROTECT_VDB here, we will probably need to */ + /* ensure that res_bytes is strictly > bytes, so that VirtualProtect */ + /* never spans regions. It seems to be OK for a VirtualFree */ + /* argument to span regions, so we should be OK for now. */ + result = (ptr_t) VirtualAlloc(NULL, res_bytes, + MEM_RESERVE | MEM_TOP_DOWN, + GC_pages_executable ? PAGE_EXECUTE_READWRITE : + PAGE_READWRITE); + if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result"); + /* If I read the documentation correctly, this can */ + /* only happen if HBLKSIZE > 64k or not a power of 2. */ + if (GC_n_heap_bases >= MAX_HEAP_SECTS) ABORT("Too many heap sections"); + if (result == NULL) return NULL; + GC_heap_bases[GC_n_heap_bases] = result; + GC_heap_lengths[GC_n_heap_bases] = 0; + GC_n_heap_bases++; + } + + /* Commit pages */ + result = (ptr_t) VirtualAlloc(result, bytes, MEM_COMMIT, + GC_pages_executable ? PAGE_EXECUTE_READWRITE : + PAGE_READWRITE); +# undef IGNORE_PAGES_EXECUTABLE + + if (result != NULL) { + if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result"); + GC_heap_lengths[i] += bytes; + } + + return(result); + } +#endif + +#ifdef USE_MUNMAP + +/* For now, this only works on Win32/WinCE and some Unix-like */ +/* systems. If you have something else, don't define */ +/* USE_MUNMAP. */ + +#if !defined(MSWIN32) && !defined(MSWINCE) + +#include +#include +#include +#include + +#endif + +/* Compute a page aligned starting address for the unmap */ +/* operation on a block of size bytes starting at start. */ +/* Return 0 if the block is too small to make this feasible. */ +STATIC ptr_t GC_unmap_start(ptr_t start, size_t bytes) +{ + ptr_t result; + /* Round start to next page boundary. */ + result = (ptr_t)((word)(start + GC_page_size - 1) & ~(GC_page_size - 1)); + if (result + GC_page_size > start + bytes) return 0; + return result; +} + +/* Compute end address for an unmap operation on the indicated */ +/* block. */ +STATIC ptr_t GC_unmap_end(ptr_t start, size_t bytes) +{ + return (ptr_t)((word)(start + bytes) & ~(GC_page_size - 1)); +} + +/* Under Win32/WinCE we commit (map) and decommit (unmap) */ +/* memory using VirtualAlloc and VirtualFree. These functions */ +/* work on individual allocations of virtual memory, made */ +/* previously using VirtualAlloc with the MEM_RESERVE flag. */ +/* The ranges we need to (de)commit may span several of these */ +/* allocations; therefore we use VirtualQuery to check */ +/* allocation lengths, and split up the range as necessary. */ + +/* We assume that GC_remap is called on exactly the same range */ +/* as a previous call to GC_unmap. It is safe to consistently */ +/* round the endpoints in both places. */ +GC_INNER void GC_unmap(ptr_t start, size_t bytes) +{ + ptr_t start_addr = GC_unmap_start(start, bytes); + ptr_t end_addr = GC_unmap_end(start, bytes); + word len = end_addr - start_addr; + if (0 == start_addr) return; +# if defined(MSWIN32) || defined(MSWINCE) + while (len != 0) { + MEMORY_BASIC_INFORMATION mem_info; + GC_word free_len; + if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info)) + != sizeof(mem_info)) + ABORT("Weird VirtualQuery result"); + free_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize; + if (!VirtualFree(start_addr, free_len, MEM_DECOMMIT)) + ABORT("VirtualFree failed"); + GC_unmapped_bytes += free_len; + start_addr += free_len; + len -= free_len; + } +# else + /* We immediately remap it to prevent an intervening mmap from */ + /* accidentally grabbing the same address space. */ + { + void * result; + result = mmap(start_addr, len, PROT_NONE, + MAP_PRIVATE | MAP_FIXED | OPT_MAP_ANON, + zero_fd, 0/* offset */); + if (result != (void *)start_addr) + ABORT("mmap(PROT_NONE) failed"); + } + GC_unmapped_bytes += len; +# endif +} + +GC_INNER void GC_remap(ptr_t start, size_t bytes) +{ + ptr_t start_addr = GC_unmap_start(start, bytes); + ptr_t end_addr = GC_unmap_end(start, bytes); + word len = end_addr - start_addr; + + /* FIXME: Handle out-of-memory correctly (at least for Win32) */ +# if defined(MSWIN32) || defined(MSWINCE) + ptr_t result; + + if (0 == start_addr) return; + while (len != 0) { + MEMORY_BASIC_INFORMATION mem_info; + GC_word alloc_len; + if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info)) + != sizeof(mem_info)) + ABORT("Weird VirtualQuery result"); + alloc_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize; + result = VirtualAlloc(start_addr, alloc_len, MEM_COMMIT, + GC_pages_executable ? PAGE_EXECUTE_READWRITE : + PAGE_READWRITE); + if (result != start_addr) { + if (GetLastError() == ERROR_NOT_ENOUGH_MEMORY || + GetLastError() == ERROR_OUTOFMEMORY) { + ABORT("Not enough memory to process remapping"); + } else { + ABORT("VirtualAlloc remapping failed"); + } + } + GC_unmapped_bytes -= alloc_len; + start_addr += alloc_len; + len -= alloc_len; + } +# else + /* It was already remapped with PROT_NONE. */ + int result; + if (0 == start_addr) return; + +# ifndef NACL + result = mprotect(start_addr, len, (PROT_READ | PROT_WRITE) + | (GC_pages_executable ? PROT_EXEC : 0)); +# else + { + /* NaCl does not expose mprotect, but mmap should work fine. */ + void *mmap_result = mmap(start_addr, len, (PROT_READ | PROT_WRITE) + | (GC_pages_executable ? PROT_EXEC : 0), + MAP_PRIVATE | MAP_FIXED | OPT_MAP_ANON, + zero_fd, 0 /* offset */); + if (mmap_result != (void *)start_addr) + ABORT("mmap as mprotect failed"); + /* Fake the return value as if mprotect succeeded. */ + result = 0; + } +# endif /* NACL */ +# undef IGNORE_PAGES_EXECUTABLE + + if (result != 0) { + if (GC_print_stats) + GC_log_printf("Mprotect failed at %p (length %lu) with errno %d\n", + start_addr, (unsigned long)len, errno); + ABORT("mprotect remapping failed"); + } + GC_unmapped_bytes -= len; +# endif +} + +/* Two adjacent blocks have already been unmapped and are about to */ +/* be merged. Unmap the whole block. This typically requires */ +/* that we unmap a small section in the middle that was not previously */ +/* unmapped due to alignment constraints. */ +GC_INNER void GC_unmap_gap(ptr_t start1, size_t bytes1, ptr_t start2, + size_t bytes2) +{ + ptr_t start1_addr = GC_unmap_start(start1, bytes1); + ptr_t end1_addr = GC_unmap_end(start1, bytes1); + ptr_t start2_addr = GC_unmap_start(start2, bytes2); + ptr_t start_addr = end1_addr; + ptr_t end_addr = start2_addr; + size_t len; + GC_ASSERT(start1 + bytes1 == start2); + if (0 == start1_addr) start_addr = GC_unmap_start(start1, bytes1 + bytes2); + if (0 == start2_addr) end_addr = GC_unmap_end(start1, bytes1 + bytes2); + if (0 == start_addr) return; + len = end_addr - start_addr; +# if defined(MSWIN32) || defined(MSWINCE) + while (len != 0) { + MEMORY_BASIC_INFORMATION mem_info; + GC_word free_len; + if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info)) + != sizeof(mem_info)) + ABORT("Weird VirtualQuery result"); + free_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize; + if (!VirtualFree(start_addr, free_len, MEM_DECOMMIT)) + ABORT("VirtualFree failed"); + GC_unmapped_bytes += free_len; + start_addr += free_len; + len -= free_len; + } +# else + if (len != 0) { + /* Immediately remap as above. */ + void * result; + result = mmap(start_addr, len, PROT_NONE, + MAP_PRIVATE | MAP_FIXED | OPT_MAP_ANON, + zero_fd, 0/* offset */); + if (result != (void *)start_addr) + ABORT("mmap(PROT_NONE) failed"); + } + GC_unmapped_bytes += len; +# endif +} + +#endif /* USE_MUNMAP */ + +/* Routine for pushing any additional roots. In THREADS */ +/* environment, this is also responsible for marking from */ +/* thread stacks. */ +#ifndef THREADS + void (*GC_push_other_roots)(void) = 0; +#else /* THREADS */ + +# ifdef PCR +PCR_ERes GC_push_thread_stack(PCR_Th_T *t, PCR_Any dummy) +{ + struct PCR_ThCtl_TInfoRep info; + PCR_ERes result; + + info.ti_stkLow = info.ti_stkHi = 0; + result = PCR_ThCtl_GetInfo(t, &info); + GC_push_all_stack((ptr_t)(info.ti_stkLow), (ptr_t)(info.ti_stkHi)); + return(result); +} + +/* Push the contents of an old object. We treat this as stack */ +/* data only because that makes it robust against mark stack */ +/* overflow. */ +PCR_ERes GC_push_old_obj(void *p, size_t size, PCR_Any data) +{ + GC_push_all_stack((ptr_t)p, (ptr_t)p + size); + return(PCR_ERes_okay); +} + +extern struct PCR_MM_ProcsRep * GC_old_allocator; + /* defined in pcr_interface.c. */ + +STATIC void GC_default_push_other_roots(void) +{ + /* Traverse data allocated by previous memory managers. */ + if ((*(GC_old_allocator->mmp_enumerate))(PCR_Bool_false, + GC_push_old_obj, 0) + != PCR_ERes_okay) { + ABORT("Old object enumeration failed"); + } + /* Traverse all thread stacks. */ + if (PCR_ERes_IsErr( + PCR_ThCtl_ApplyToAllOtherThreads(GC_push_thread_stack,0)) + || PCR_ERes_IsErr(GC_push_thread_stack(PCR_Th_CurrThread(), 0))) { + ABORT("Thread stack marking failed"); + } +} + +# endif /* PCR */ + +# if defined(GC_PTHREADS) || defined(GC_WIN32_THREADS) + STATIC void GC_default_push_other_roots(void) + { + GC_push_all_stacks(); + } +# endif /* GC_WIN32_THREADS || GC_PTHREADS */ + +# ifdef SN_TARGET_PS3 + STATIC void GC_default_push_other_roots(void) + { + ABORT("GC_default_push_other_roots is not implemented"); + } + + void GC_push_thread_structures(void) + { + ABORT("GC_push_thread_structures is not implemented"); + } +# endif /* SN_TARGET_PS3 */ + + void (*GC_push_other_roots)(void) = GC_default_push_other_roots; +#endif /* THREADS */ + +/* + * Routines for accessing dirty bits on virtual pages. + * There are six ways to maintain this information: + * DEFAULT_VDB: A simple dummy implementation that treats every page + * as possibly dirty. This makes incremental collection + * useless, but the implementation is still correct. + * MANUAL_VDB: Stacks and static data are always considered dirty. + * Heap pages are considered dirty if GC_dirty(p) has been + * called on some pointer p pointing to somewhere inside + * an object on that page. A GC_dirty() call on a large + * object directly dirties only a single page, but for + * MANUAL_VDB we are careful to treat an object with a dirty + * page as completely dirty. + * In order to avoid races, an object must be marked dirty + * after it is written, and a reference to the object + * must be kept on a stack or in a register in the interim. + * With threads enabled, an object directly reachable from the + * stack at the time of a collection is treated as dirty. + * In single-threaded mode, it suffices to ensure that no + * collection can take place between the pointer assignment + * and the GC_dirty() call. + * PCR_VDB: Use PPCRs virtual dirty bit facility. + * PROC_VDB: Use the /proc facility for reading dirty bits. Only + * works under some SVR4 variants. Even then, it may be + * too slow to be entirely satisfactory. Requires reading + * dirty bits for entire address space. Implementations tend + * to assume that the client is a (slow) debugger. + * MPROTECT_VDB:Protect pages and then catch the faults to keep track of + * dirtied pages. The implementation (and implementability) + * is highly system dependent. This usually fails when system + * calls write to a protected page. We prevent the read system + * call from doing so. It is the clients responsibility to + * make sure that other system calls are similarly protected + * or write only to the stack. + * GWW_VDB: Use the Win32 GetWriteWatch functions, if available, to + * read dirty bits. In case it is not available (because we + * are running on Windows 95, Windows 2000 or earlier), + * MPROTECT_VDB may be defined as a fallback strategy. + */ +#ifndef GC_DISABLE_INCREMENTAL + GC_INNER GC_bool GC_dirty_maintained = FALSE; +#endif + +#if defined(PROC_VDB) || defined(GWW_VDB) + /* Add all pages in pht2 to pht1 */ + STATIC void GC_or_pages(page_hash_table pht1, page_hash_table pht2) + { + register unsigned i; + for (i = 0; i < PHT_SIZE; i++) pht1[i] |= pht2[i]; + } + +# ifdef MPROTECT_VDB + STATIC GC_bool GC_gww_page_was_dirty(struct hblk * h) +# else + GC_INNER GC_bool GC_page_was_dirty(struct hblk * h) +# endif + { + register word index; + if (HDR(h) == 0) + return TRUE; + index = PHT_HASH(h); + return get_pht_entry_from_index(GC_grungy_pages, index); + } + +# if defined(CHECKSUMS) || defined(PROC_VDB) + /* Used only if GWW_VDB. */ +# ifdef MPROTECT_VDB + STATIC GC_bool GC_gww_page_was_ever_dirty(struct hblk * h) +# else + GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk * h) +# endif + { + register word index; + if (HDR(h) == 0) + return TRUE; + index = PHT_HASH(h); + return get_pht_entry_from_index(GC_written_pages, index); + } +# endif /* CHECKSUMS || PROC_VDB */ + +# ifndef MPROTECT_VDB + /* Ignore write hints. They don't help us here. */ + /*ARGSUSED*/ + GC_INNER void GC_remove_protection(struct hblk *h, word nblocks, + GC_bool is_ptrfree) {} +# endif + +#endif /* PROC_VDB || GWW_VDB */ + +#ifdef GWW_VDB + +# define GC_GWW_BUF_LEN (MAXHINCR * HBLKSIZE / 4096 /* X86 page size */) + /* Still susceptible to overflow, if there are very large allocations, */ + /* and everything is dirty. */ + static PVOID gww_buf[GC_GWW_BUF_LEN]; + +# ifdef MPROTECT_VDB + GC_INNER GC_bool GC_gww_dirty_init(void) + { + detect_GetWriteWatch(); + return GC_GWW_AVAILABLE(); + } +# else + GC_INNER void GC_dirty_init(void) + { + detect_GetWriteWatch(); + GC_dirty_maintained = GC_GWW_AVAILABLE(); + } +# endif /* !MPROTECT_VDB */ + +# ifdef MPROTECT_VDB + STATIC void GC_gww_read_dirty(void) +# else + GC_INNER void GC_read_dirty(void) +# endif + { + word i; + + BZERO(GC_grungy_pages, sizeof(GC_grungy_pages)); + + for (i = 0; i != GC_n_heap_sects; ++i) { + GC_ULONG_PTR count; + + do { + PVOID * pages, * pages_end; + DWORD page_size; + + pages = gww_buf; + count = GC_GWW_BUF_LEN; + /* GetWriteWatch is documented as returning non-zero when it */ + /* fails, but the documentation doesn't explicitly say why it */ + /* would fail or what its behaviour will be if it fails. */ + /* It does appear to fail, at least on recent W2K instances, if */ + /* the underlying memory was not allocated with the appropriate */ + /* flag. This is common if GC_enable_incremental is called */ + /* shortly after GC initialization. To avoid modifying the */ + /* interface, we silently work around such a failure, it only */ + /* affects the initial (small) heap allocation. If there are */ + /* more dirty pages than will fit in the buffer, this is not */ + /* treated as a failure; we must check the page count in the */ + /* loop condition. Since each partial call will reset the */ + /* status of some pages, this should eventually terminate even */ + /* in the overflow case. */ + if (GetWriteWatch_func(WRITE_WATCH_FLAG_RESET, + GC_heap_sects[i].hs_start, + GC_heap_sects[i].hs_bytes, + pages, + &count, + &page_size) != 0) { + static int warn_count = 0; + unsigned j; + struct hblk * start = (struct hblk *)GC_heap_sects[i].hs_start; + static struct hblk *last_warned = 0; + size_t nblocks = divHBLKSZ(GC_heap_sects[i].hs_bytes); + + if ( i != 0 && last_warned != start && warn_count++ < 5) { + last_warned = start; + WARN( + "GC_gww_read_dirty unexpectedly failed at %p: " + "Falling back to marking all pages dirty\n", start); + } + for (j = 0; j < nblocks; ++j) { + word hash = PHT_HASH(start + j); + set_pht_entry_from_index(GC_grungy_pages, hash); + } + count = 1; /* Done with this section. */ + } else /* succeeded */ { + pages_end = pages + count; + while (pages != pages_end) { + struct hblk * h = (struct hblk *) *pages++; + struct hblk * h_end = (struct hblk *) ((char *) h + page_size); + do + set_pht_entry_from_index(GC_grungy_pages, PHT_HASH(h)); + while (++h < h_end); + } + } + } while (count == GC_GWW_BUF_LEN); + /* FIXME: It's unclear from Microsoft's documentation if this loop */ + /* is useful. We suspect the call just fails if the buffer fills */ + /* up. But that should still be handled correctly. */ + } + + GC_or_pages(GC_written_pages, GC_grungy_pages); + } +#endif /* GWW_VDB */ + +#ifdef DEFAULT_VDB + /* All of the following assume the allocation lock is held. */ + + /* The client asserts that unallocated pages in the heap are never */ + /* written. */ + + /* Initialize virtual dirty bit implementation. */ + GC_INNER void GC_dirty_init(void) + { + if (GC_print_stats == VERBOSE) + GC_log_printf("Initializing DEFAULT_VDB...\n"); + GC_dirty_maintained = TRUE; + } + + /* Retrieve system dirty bits for heap to a local buffer. */ + /* Restore the systems notion of which pages are dirty. */ + GC_INNER void GC_read_dirty(void) {} + + /* Is the HBLKSIZE sized page at h marked dirty in the local buffer? */ + /* If the actual page size is different, this returns TRUE if any */ + /* of the pages overlapping h are dirty. This routine may err on the */ + /* side of labeling pages as dirty (and this implementation does). */ + /*ARGSUSED*/ + GC_INNER GC_bool GC_page_was_dirty(struct hblk *h) + { + return(TRUE); + } + + /* The following two routines are typically less crucial. */ + /* They matter most with large dynamic libraries, or if we can't */ + /* accurately identify stacks, e.g. under Solaris 2.X. Otherwise the */ + /* following default versions are adequate. */ +# ifdef CHECKSUMS + /* Could any valid GC heap pointer ever have been written to this page? */ + /*ARGSUSED*/ + GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk *h) + { + return(TRUE); + } +# endif /* CHECKSUMS */ + + /* A call that: */ + /* I) hints that [h, h+nblocks) is about to be written. */ + /* II) guarantees that protection is removed. */ + /* (I) may speed up some dirty bit implementations. */ + /* (II) may be essential if we need to ensure that */ + /* pointer-free system call buffers in the heap are */ + /* not protected. */ + /*ARGSUSED*/ + GC_INNER void GC_remove_protection(struct hblk *h, word nblocks, + GC_bool is_ptrfree) {} +#endif /* DEFAULT_VDB */ + +#ifdef MANUAL_VDB + /* Initialize virtual dirty bit implementation. */ + GC_INNER void GC_dirty_init(void) + { + if (GC_print_stats == VERBOSE) + GC_log_printf("Initializing MANUAL_VDB...\n"); + /* GC_dirty_pages and GC_grungy_pages are already cleared. */ + GC_dirty_maintained = TRUE; + } + + /* Retrieve system dirty bits for heap to a local buffer. */ + /* Restore the systems notion of which pages are dirty. */ + GC_INNER void GC_read_dirty(void) + { + BCOPY((word *)GC_dirty_pages, GC_grungy_pages, + (sizeof GC_dirty_pages)); + BZERO((word *)GC_dirty_pages, (sizeof GC_dirty_pages)); + } + + /* Is the HBLKSIZE sized page at h marked dirty in the local buffer? */ + /* If the actual page size is different, this returns TRUE if any */ + /* of the pages overlapping h are dirty. This routine may err on the */ + /* side of labeling pages as dirty (and this implementation does). */ + GC_INNER GC_bool GC_page_was_dirty(struct hblk *h) + { + register word index = PHT_HASH(h); + return(HDR(h) == 0 || get_pht_entry_from_index(GC_grungy_pages, index)); + } + +# define async_set_pht_entry_from_index(db, index) \ + set_pht_entry_from_index(db, index) /* for now */ + + /* Mark the page containing p as dirty. Logically, this dirties the */ + /* entire object. */ + void GC_dirty(ptr_t p) + { + word index = PHT_HASH(p); + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + + /*ARGSUSED*/ + GC_INNER void GC_remove_protection(struct hblk *h, word nblocks, + GC_bool is_ptrfree) {} + +# ifdef CHECKSUMS + /* Could any valid GC heap pointer ever have been written to this page? */ + /*ARGSUSED*/ + GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk *h) + { + /* FIXME - implement me. */ + return(TRUE); + } +# endif /* CHECKSUMS */ + +#endif /* MANUAL_VDB */ + +#ifdef MPROTECT_VDB + /* See DEFAULT_VDB for interface descriptions. */ + + /* + * This implementation maintains dirty bits itself by catching write + * faults and keeping track of them. We assume nobody else catches + * SIGBUS or SIGSEGV. We assume no write faults occur in system calls. + * This means that clients must ensure that system calls don't write + * to the write-protected heap. Probably the best way to do this is to + * ensure that system calls write at most to POINTERFREE objects in the + * heap, and do even that only if we are on a platform on which those + * are not protected. Another alternative is to wrap system calls + * (see example for read below), but the current implementation holds + * applications. + * We assume the page size is a multiple of HBLKSIZE. + * We prefer them to be the same. We avoid protecting POINTERFREE + * objects only if they are the same. + */ +# ifdef DARWIN + /* Using vm_protect (mach syscall) over mprotect (BSD syscall) seems to + decrease the likelihood of some of the problems described below. */ +# include + STATIC mach_port_t GC_task_self = 0; +# define PROTECT(addr,len) \ + if(vm_protect(GC_task_self,(vm_address_t)(addr),(vm_size_t)(len), \ + FALSE, VM_PROT_READ \ + | (GC_pages_executable ? VM_PROT_EXECUTE : 0)) \ + != KERN_SUCCESS) { \ + ABORT("vm_protect(PROTECT) failed"); \ + } +# define UNPROTECT(addr,len) \ + if(vm_protect(GC_task_self,(vm_address_t)(addr),(vm_size_t)(len), \ + FALSE, (VM_PROT_READ | VM_PROT_WRITE) \ + | (GC_pages_executable ? VM_PROT_EXECUTE : 0)) \ + != KERN_SUCCESS) { \ + ABORT("vm_protect(UNPROTECT) failed"); \ + } + +# elif !defined(MSWIN32) && !defined(MSWINCE) +# include +# include +# include + +# define PROTECT(addr, len) \ + if (mprotect((caddr_t)(addr), (size_t)(len), \ + PROT_READ \ + | (GC_pages_executable ? PROT_EXEC : 0)) < 0) { \ + ABORT("mprotect failed"); \ + } +# define UNPROTECT(addr, len) \ + if (mprotect((caddr_t)(addr), (size_t)(len), \ + (PROT_READ | PROT_WRITE) \ + | (GC_pages_executable ? PROT_EXEC : 0)) < 0) { \ + ABORT(GC_pages_executable ? "un-mprotect executable page" \ + " failed (probably disabled by OS)" : \ + "un-mprotect failed"); \ + } +# undef IGNORE_PAGES_EXECUTABLE + +# else /* MSWIN32 */ +# ifndef MSWINCE +# include +# endif + + static DWORD protect_junk; +# define PROTECT(addr, len) \ + if (!VirtualProtect((addr), (len), \ + GC_pages_executable ? PAGE_EXECUTE_READ : \ + PAGE_READONLY, \ + &protect_junk)) { \ + if (GC_print_stats) \ + GC_log_printf("Last error code: 0x%lx\n", (long)GetLastError()); \ + ABORT("VirtualProtect failed"); \ + } +# define UNPROTECT(addr, len) \ + if (!VirtualProtect((addr), (len), \ + GC_pages_executable ? PAGE_EXECUTE_READWRITE : \ + PAGE_READWRITE, \ + &protect_junk)) { \ + ABORT("un-VirtualProtect failed"); \ + } +# endif /* MSWIN32 || MSWINCE || DARWIN */ + +# if defined(MSWIN32) + typedef LPTOP_LEVEL_EXCEPTION_FILTER SIG_HNDLR_PTR; +# undef SIG_DFL +# define SIG_DFL (LPTOP_LEVEL_EXCEPTION_FILTER)((signed_word)-1) +# elif defined(MSWINCE) + typedef LONG (WINAPI *SIG_HNDLR_PTR)(struct _EXCEPTION_POINTERS *); +# undef SIG_DFL +# define SIG_DFL (SIG_HNDLR_PTR) (-1) +# elif defined(DARWIN) + typedef void (* SIG_HNDLR_PTR)(); +# else + typedef void (* SIG_HNDLR_PTR)(int, siginfo_t *, void *); + typedef void (* PLAIN_HNDLR_PTR)(int); +# endif + +# if defined(__GLIBC__) +# if __GLIBC__ < 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ < 2 +# error glibc too old? +# endif +# endif + +#ifndef DARWIN + STATIC SIG_HNDLR_PTR GC_old_segv_handler = 0; + /* Also old MSWIN32 ACCESS_VIOLATION filter */ +# if !defined(MSWIN32) && !defined(MSWINCE) + STATIC SIG_HNDLR_PTR GC_old_bus_handler = 0; + STATIC GC_bool GC_old_bus_handler_used_si = FALSE; + STATIC GC_bool GC_old_segv_handler_used_si = FALSE; +# endif +#endif /* !DARWIN */ + +#if defined(THREADS) +/* We need to lock around the bitmap update in the write fault handler */ +/* in order to avoid the risk of losing a bit. We do this with a */ +/* test-and-set spin lock if we know how to do that. Otherwise we */ +/* check whether we are already in the handler and use the dumb but */ +/* safe fallback algorithm of setting all bits in the word. */ +/* Contention should be very rare, so we do the minimum to handle it */ +/* correctly. */ +#ifdef AO_HAVE_test_and_set_acquire + GC_INNER volatile AO_TS_t GC_fault_handler_lock = AO_TS_INITIALIZER; + static void async_set_pht_entry_from_index(volatile page_hash_table db, + size_t index) + { + while (AO_test_and_set_acquire(&GC_fault_handler_lock) == AO_TS_SET) { + /* empty */ + } + /* Could also revert to set_pht_entry_from_index_safe if initial */ + /* GC_test_and_set fails. */ + set_pht_entry_from_index(db, index); + AO_CLEAR(&GC_fault_handler_lock); + } +#else /* !AO_HAVE_test_and_set_acquire */ +# error No test_and_set operation: Introduces a race. + /* THIS WOULD BE INCORRECT! */ + /* The dirty bit vector may be temporarily wrong, */ + /* just before we notice the conflict and correct it. We may end up */ + /* looking at it while it's wrong. But this requires contention */ + /* exactly when a GC is triggered, which seems far less likely to */ + /* fail than the old code, which had no reported failures. Thus we */ + /* leave it this way while we think of something better, or support */ + /* GC_test_and_set on the remaining platforms. */ + static volatile word currently_updating = 0; + static void async_set_pht_entry_from_index(volatile page_hash_table db, + size_t index) + { + unsigned int update_dummy; + currently_updating = (word)(&update_dummy); + set_pht_entry_from_index(db, index); + /* If we get contention in the 10 or so instruction window here, */ + /* and we get stopped by a GC between the two updates, we lose! */ + if (currently_updating != (word)(&update_dummy)) { + set_pht_entry_from_index_safe(db, index); + /* We claim that if two threads concurrently try to update the */ + /* dirty bit vector, the first one to execute UPDATE_START */ + /* will see it changed when UPDATE_END is executed. (Note that */ + /* &update_dummy must differ in two distinct threads.) It */ + /* will then execute set_pht_entry_from_index_safe, thus */ + /* returning us to a safe state, though not soon enough. */ + } + } +#endif /* !AO_HAVE_test_and_set_acquire */ +#else /* !THREADS */ +# define async_set_pht_entry_from_index(db, index) \ + set_pht_entry_from_index(db, index) +#endif /* !THREADS */ + +#ifdef CHECKSUMS + void GC_record_fault(struct hblk * h); /* from checksums.c */ +#endif + +#ifndef DARWIN + +# if !defined(MSWIN32) && !defined(MSWINCE) +# include +# if defined(FREEBSD) || defined(HURD) || defined(HPUX) +# define SIG_OK (sig == SIGBUS || sig == SIGSEGV) +# else +# define SIG_OK (sig == SIGSEGV) +# endif +# if defined(FREEBSD) +# ifndef SEGV_ACCERR +# define SEGV_ACCERR 2 +# endif +# define CODE_OK (si -> si_code == BUS_PAGE_FAULT \ + || si -> si_code == SEGV_ACCERR) +# elif defined(OSF1) +# define CODE_OK (si -> si_code == 2 /* experimentally determined */) +# elif defined(IRIX5) +# define CODE_OK (si -> si_code == EACCES) +# elif defined(HURD) +# define CODE_OK TRUE +# elif defined(LINUX) +# define CODE_OK TRUE + /* Empirically c.trapno == 14, on IA32, but is that useful? */ + /* Should probably consider alignment issues on other */ + /* architectures. */ +# elif defined(HPUX) +# define CODE_OK (si -> si_code == SEGV_ACCERR \ + || si -> si_code == BUS_ADRERR \ + || si -> si_code == BUS_UNKNOWN \ + || si -> si_code == SEGV_UNKNOWN \ + || si -> si_code == BUS_OBJERR) +# elif defined(SUNOS5SIGS) +# define CODE_OK (si -> si_code == SEGV_ACCERR) +# endif +# ifndef NO_GETCONTEXT +# include +# endif + /*ARGSUSED*/ + STATIC void GC_write_fault_handler(int sig, siginfo_t *si, void *raw_sc) +# else +# define SIG_OK (exc_info -> ExceptionRecord -> ExceptionCode \ + == STATUS_ACCESS_VIOLATION) +# define CODE_OK (exc_info -> ExceptionRecord -> ExceptionInformation[0] \ + == 1) /* Write fault */ + STATIC LONG WINAPI GC_write_fault_handler( + struct _EXCEPTION_POINTERS *exc_info) +# endif /* MSWIN32 || MSWINCE */ + { +# if !defined(MSWIN32) && !defined(MSWINCE) + char *addr = si -> si_addr; +# else + char * addr = (char *) (exc_info -> ExceptionRecord + -> ExceptionInformation[1]); +# endif + unsigned i; + + if (SIG_OK && CODE_OK) { + register struct hblk * h = + (struct hblk *)((word)addr & ~(GC_page_size-1)); + GC_bool in_allocd_block; +# ifdef CHECKSUMS + GC_record_fault(h); +# endif + +# ifdef SUNOS5SIGS + /* Address is only within the correct physical page. */ + in_allocd_block = FALSE; + for (i = 0; i < divHBLKSZ(GC_page_size); i++) { + if (HDR(h+i) != 0) { + in_allocd_block = TRUE; + break; + } + } +# else + in_allocd_block = (HDR(addr) != 0); +# endif + if (!in_allocd_block) { + /* FIXME - We should make sure that we invoke the */ + /* old handler with the appropriate calling */ + /* sequence, which often depends on SA_SIGINFO. */ + + /* Heap blocks now begin and end on page boundaries */ + SIG_HNDLR_PTR old_handler; + +# if defined(MSWIN32) || defined(MSWINCE) + old_handler = GC_old_segv_handler; +# else + GC_bool used_si; + + if (sig == SIGSEGV) { + old_handler = GC_old_segv_handler; + used_si = GC_old_segv_handler_used_si; + } else { + old_handler = GC_old_bus_handler; + used_si = GC_old_bus_handler_used_si; + } +# endif + + if (old_handler == (SIG_HNDLR_PTR)SIG_DFL) { +# if !defined(MSWIN32) && !defined(MSWINCE) + if (GC_print_stats) + GC_log_printf("Unexpected segfault at %p\n", addr); + ABORT("Unexpected bus error or segmentation fault"); +# else + return(EXCEPTION_CONTINUE_SEARCH); +# endif + } else { + /* + * FIXME: This code should probably check if the + * old signal handler used the traditional style and + * if so call it using that style. + */ +# if defined(MSWIN32) || defined(MSWINCE) + return((*old_handler)(exc_info)); +# else + if (used_si) + ((SIG_HNDLR_PTR)old_handler) (sig, si, raw_sc); + else + /* FIXME: should pass nonstandard args as well. */ + ((PLAIN_HNDLR_PTR)old_handler) (sig); + return; +# endif + } + } + UNPROTECT(h, GC_page_size); + /* We need to make sure that no collection occurs between */ + /* the UNPROTECT and the setting of the dirty bit. Otherwise */ + /* a write by a third thread might go unnoticed. Reversing */ + /* the order is just as bad, since we would end up unprotecting */ + /* a page in a GC cycle during which it's not marked. */ + /* Currently we do this by disabling the thread stopping */ + /* signals while this handler is running. An alternative might */ + /* be to record the fact that we're about to unprotect, or */ + /* have just unprotected a page in the GC's thread structure, */ + /* and then to have the thread stopping code set the dirty */ + /* flag, if necessary. */ + for (i = 0; i < divHBLKSZ(GC_page_size); i++) { + size_t index = PHT_HASH(h+i); + + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + /* The write may not take place before dirty bits are read. */ + /* But then we'll fault again ... */ +# if defined(MSWIN32) || defined(MSWINCE) + return(EXCEPTION_CONTINUE_EXECUTION); +# else + return; +# endif + } +# if defined(MSWIN32) || defined(MSWINCE) + return EXCEPTION_CONTINUE_SEARCH; +# else + if (GC_print_stats) + GC_log_printf("Unexpected segfault at %p\n", addr); + ABORT("Unexpected bus error or segmentation fault"); +# endif + } + +# ifdef GC_WIN32_THREADS + GC_INNER void GC_set_write_fault_handler(void) + { + SetUnhandledExceptionFilter(GC_write_fault_handler); + } +# endif +#endif /* !DARWIN */ + +/* We hold the allocation lock. We expect block h to be written */ +/* shortly. Ensure that all pages containing any part of the n hblks */ +/* starting at h are no longer protected. If is_ptrfree is false, also */ +/* ensure that they will subsequently appear to be dirty. Not allowed */ +/* to call GC_printf (and the friends) here, see Win32 GC_stop_world() */ +/* for the information. */ +GC_INNER void GC_remove_protection(struct hblk *h, word nblocks, + GC_bool is_ptrfree) +{ + struct hblk * h_trunc; /* Truncated to page boundary */ + struct hblk * h_end; /* Page boundary following block end */ + struct hblk * current; + +# if defined(GWW_VDB) + if (GC_GWW_AVAILABLE()) return; +# endif + if (!GC_dirty_maintained) return; + h_trunc = (struct hblk *)((word)h & ~(GC_page_size-1)); + h_end = (struct hblk *)(((word)(h + nblocks) + GC_page_size-1) + & ~(GC_page_size-1)); + if (h_end == h_trunc + 1 && + get_pht_entry_from_index(GC_dirty_pages, PHT_HASH(h_trunc))) { + /* already marked dirty, and hence unprotected. */ + return; + } + for (current = h_trunc; current < h_end; ++current) { + size_t index = PHT_HASH(current); + if (!is_ptrfree || current < h || current >= h + nblocks) { + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + } + UNPROTECT(h_trunc, (ptr_t)h_end - (ptr_t)h_trunc); +} + +#if !defined(DARWIN) + GC_INNER void GC_dirty_init(void) + { +# if !defined(MSWIN32) && !defined(MSWINCE) + struct sigaction act, oldact; + act.sa_flags = SA_RESTART | SA_SIGINFO; + act.sa_sigaction = GC_write_fault_handler; + (void)sigemptyset(&act.sa_mask); +# ifdef SIG_SUSPEND + /* Arrange to postpone SIG_SUSPEND while we're in a write fault */ + /* handler. This effectively makes the handler atomic w.r.t. */ + /* stopping the world for GC. */ + (void)sigaddset(&act.sa_mask, SIG_SUSPEND); +# endif /* SIG_SUSPEND */ +# endif + if (GC_print_stats == VERBOSE) + GC_log_printf( + "Initializing mprotect virtual dirty bit implementation\n"); + GC_dirty_maintained = TRUE; + if (GC_page_size % HBLKSIZE != 0) { + ABORT("Page size not multiple of HBLKSIZE"); + } +# if !defined(MSWIN32) && !defined(MSWINCE) +# if defined(GC_IRIX_THREADS) + sigaction(SIGSEGV, 0, &oldact); + sigaction(SIGSEGV, &act, 0); +# else + { + int res = sigaction(SIGSEGV, &act, &oldact); + if (res != 0) ABORT("Sigaction failed"); + } +# endif + if (oldact.sa_flags & SA_SIGINFO) { + GC_old_segv_handler = oldact.sa_sigaction; + GC_old_segv_handler_used_si = TRUE; + } else { + GC_old_segv_handler = (SIG_HNDLR_PTR)oldact.sa_handler; + GC_old_segv_handler_used_si = FALSE; + } + if (GC_old_segv_handler == (SIG_HNDLR_PTR)SIG_IGN) { + if (GC_print_stats) + GC_err_printf("Previously ignored segmentation violation!?\n"); + GC_old_segv_handler = (SIG_HNDLR_PTR)SIG_DFL; + } + if (GC_old_segv_handler != (SIG_HNDLR_PTR)SIG_DFL) { + if (GC_print_stats == VERBOSE) + GC_log_printf("Replaced other SIGSEGV handler\n"); + } +# if defined(HPUX) || defined(LINUX) || defined(HURD) \ + || (defined(FREEBSD) && defined(SUNOS5SIGS)) + sigaction(SIGBUS, &act, &oldact); + if (oldact.sa_flags & SA_SIGINFO) { + GC_old_bus_handler = oldact.sa_sigaction; + GC_old_bus_handler_used_si = TRUE; + } else { + GC_old_bus_handler = (SIG_HNDLR_PTR)oldact.sa_handler; + GC_old_bus_handler_used_si = FALSE; + } + if (GC_old_bus_handler == (SIG_HNDLR_PTR)SIG_IGN) { + if (GC_print_stats) + GC_err_printf("Previously ignored bus error!?\n"); + GC_old_bus_handler = (SIG_HNDLR_PTR)SIG_DFL; + } + if (GC_old_bus_handler != (SIG_HNDLR_PTR)SIG_DFL) { + if (GC_print_stats == VERBOSE) + GC_log_printf("Replaced other SIGBUS handler\n"); + } +# endif /* HPUX || LINUX || HURD || (FREEBSD && SUNOS5SIGS) */ +# endif /* ! MS windows */ +# if defined(GWW_VDB) + if (GC_gww_dirty_init()) + return; +# endif +# if defined(MSWIN32) + GC_old_segv_handler = SetUnhandledExceptionFilter(GC_write_fault_handler); + if (GC_old_segv_handler != NULL) { + if (GC_print_stats) + GC_log_printf("Replaced other UnhandledExceptionFilter\n"); + } else { + GC_old_segv_handler = SIG_DFL; + } +# elif defined(MSWINCE) + /* MPROTECT_VDB is unsupported for WinCE at present. */ + /* FIXME: implement it (if possible). */ +# endif + } +#endif /* !DARWIN */ + +GC_API int GC_CALL GC_incremental_protection_needs(void) +{ + if (GC_page_size == HBLKSIZE) { + return GC_PROTECTS_POINTER_HEAP; + } else { + return GC_PROTECTS_POINTER_HEAP | GC_PROTECTS_PTRFREE_HEAP; + } +} +#define HAVE_INCREMENTAL_PROTECTION_NEEDS + +#define IS_PTRFREE(hhdr) ((hhdr)->hb_descr == 0) +#define PAGE_ALIGNED(x) !((word)(x) & (GC_page_size - 1)) + +STATIC void GC_protect_heap(void) +{ + ptr_t start; + size_t len; + struct hblk * current; + struct hblk * current_start; /* Start of block to be protected. */ + struct hblk * limit; + unsigned i; + GC_bool protect_all = + (0 != (GC_incremental_protection_needs() & GC_PROTECTS_PTRFREE_HEAP)); + for (i = 0; i < GC_n_heap_sects; i++) { + start = GC_heap_sects[i].hs_start; + len = GC_heap_sects[i].hs_bytes; + if (protect_all) { + PROTECT(start, len); + } else { + GC_ASSERT(PAGE_ALIGNED(len)); + GC_ASSERT(PAGE_ALIGNED(start)); + current_start = current = (struct hblk *)start; + limit = (struct hblk *)(start + len); + while (current < limit) { + hdr * hhdr; + word nhblks; + GC_bool is_ptrfree; + + GC_ASSERT(PAGE_ALIGNED(current)); + GET_HDR(current, hhdr); + if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) { + /* This can happen only if we're at the beginning of a */ + /* heap segment, and a block spans heap segments. */ + /* We will handle that block as part of the preceding */ + /* segment. */ + GC_ASSERT(current_start == current); + current_start = ++current; + continue; + } + if (HBLK_IS_FREE(hhdr)) { + GC_ASSERT(PAGE_ALIGNED(hhdr -> hb_sz)); + nhblks = divHBLKSZ(hhdr -> hb_sz); + is_ptrfree = TRUE; /* dirty on alloc */ + } else { + nhblks = OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz); + is_ptrfree = IS_PTRFREE(hhdr); + } + if (is_ptrfree) { + if (current_start < current) { + PROTECT(current_start, (ptr_t)current - (ptr_t)current_start); + } + current_start = (current += nhblks); + } else { + current += nhblks; + } + } + if (current_start < current) { + PROTECT(current_start, (ptr_t)current - (ptr_t)current_start); + } + } + } +} + +/* We assume that either the world is stopped or its OK to lose dirty */ +/* bits while this is happenning (as in GC_enable_incremental). */ +GC_INNER void GC_read_dirty(void) +{ +# if defined(GWW_VDB) + if (GC_GWW_AVAILABLE()) { + GC_gww_read_dirty(); + return; + } +# endif + BCOPY((word *)GC_dirty_pages, GC_grungy_pages, + (sizeof GC_dirty_pages)); + BZERO((word *)GC_dirty_pages, (sizeof GC_dirty_pages)); + GC_protect_heap(); +} + +GC_INNER GC_bool GC_page_was_dirty(struct hblk *h) +{ + register word index; + +# if defined(GWW_VDB) + if (GC_GWW_AVAILABLE()) + return GC_gww_page_was_dirty(h); +# endif + + index = PHT_HASH(h); + return(HDR(h) == 0 || get_pht_entry_from_index(GC_grungy_pages, index)); +} + +/* + * Acquiring the allocation lock here is dangerous, since this + * can be called from within GC_call_with_alloc_lock, and the cord + * package does so. On systems that allow nested lock acquisition, this + * happens to work. + * On other systems, SET_LOCK_HOLDER and friends must be suitably defined. + */ + +#if 0 +static GC_bool syscall_acquired_lock = FALSE; /* Protected by GC lock. */ + +void GC_begin_syscall(void) +{ + /* FIXME: Resurrecting this code would require fixing the */ + /* test, which can spuriously return TRUE. */ + if (!I_HOLD_LOCK()) { + LOCK(); + syscall_acquired_lock = TRUE; + } +} + +void GC_end_syscall(void) +{ + if (syscall_acquired_lock) { + syscall_acquired_lock = FALSE; + UNLOCK(); + } +} + +void GC_unprotect_range(ptr_t addr, word len) +{ + struct hblk * start_block; + struct hblk * end_block; + register struct hblk *h; + ptr_t obj_start; + + if (!GC_dirty_maintained) return; + obj_start = GC_base(addr); + if (obj_start == 0) return; + if (GC_base(addr + len - 1) != obj_start) { + ABORT("GC_unprotect_range(range bigger than object)"); + } + start_block = (struct hblk *)((word)addr & ~(GC_page_size - 1)); + end_block = (struct hblk *)((word)(addr + len - 1) & ~(GC_page_size - 1)); + end_block += GC_page_size/HBLKSIZE - 1; + for (h = start_block; h <= end_block; h++) { + register word index = PHT_HASH(h); + + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + UNPROTECT(start_block, + ((ptr_t)end_block - (ptr_t)start_block) + HBLKSIZE); +} + + +/* We no longer wrap read by default, since that was causing too many */ +/* problems. It is preferred that the client instead avoids writing */ +/* to the write-protected heap with a system call. */ +/* This still serves as sample code if you do want to wrap system calls.*/ + +#if !defined(MSWIN32) && !defined(MSWINCE) && !defined(GC_USE_LD_WRAP) +/* Replacement for UNIX system call. */ +/* Other calls that write to the heap should be handled similarly. */ +/* Note that this doesn't work well for blocking reads: It will hold */ +/* the allocation lock for the entire duration of the call. Multithreaded */ +/* clients should really ensure that it won't block, either by setting */ +/* the descriptor nonblocking, or by calling select or poll first, to */ +/* make sure that input is available. */ +/* Another, preferred alternative is to ensure that system calls never */ +/* write to the protected heap (see above). */ +# include +# include +ssize_t read(int fd, void *buf, size_t nbyte) +{ + int result; + + GC_begin_syscall(); + GC_unprotect_range(buf, (word)nbyte); +# if defined(IRIX5) || defined(GC_LINUX_THREADS) + /* Indirect system call may not always be easily available. */ + /* We could call _read, but that would interfere with the */ + /* libpthread interception of read. */ + /* On Linux, we have to be careful with the linuxthreads */ + /* read interception. */ + { + struct iovec iov; + + iov.iov_base = buf; + iov.iov_len = nbyte; + result = readv(fd, &iov, 1); + } +# else +# if defined(HURD) + result = __read(fd, buf, nbyte); +# else + /* The two zero args at the end of this list are because one + IA-64 syscall() implementation actually requires six args + to be passed, even though they aren't always used. */ + result = syscall(SYS_read, fd, buf, nbyte, 0, 0); +# endif /* !HURD */ +# endif + GC_end_syscall(); + return(result); +} +#endif /* !MSWIN32 && !MSWINCE && !GC_LINUX_THREADS */ + +#if defined(GC_USE_LD_WRAP) && !defined(THREADS) + /* We use the GNU ld call wrapping facility. */ + /* I'm not sure that this actually wraps whatever version of read */ + /* is called by stdio. That code also mentions __read. */ +# include + ssize_t __wrap_read(int fd, void *buf, size_t nbyte) + { + int result; + + GC_begin_syscall(); + GC_unprotect_range(buf, (word)nbyte); + result = __real_read(fd, buf, nbyte); + GC_end_syscall(); + return(result); + } + + /* We should probably also do this for __read, or whatever stdio */ + /* actually calls. */ +#endif +#endif /* 0 */ + +# ifdef CHECKSUMS + /*ARGSUSED*/ + GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk *h) + { +# if defined(GWW_VDB) + if (GC_GWW_AVAILABLE()) + return GC_gww_page_was_ever_dirty(h); +# endif + return(TRUE); + } +# endif /* CHECKSUMS */ + +#endif /* MPROTECT_VDB */ + +#ifdef PROC_VDB +/* See DEFAULT_VDB for interface descriptions. */ + +/* This implementation assumes a Solaris 2.X like /proc */ +/* pseudo-file-system from which we can read page modified bits. This */ +/* facility is far from optimal (e.g. we would like to get the info for */ +/* only some of the address space), but it avoids intercepting system */ +/* calls. */ + +# include +# include +# include +# include +# include +# include +# include + +# define INITIAL_BUF_SZ 16384 + STATIC word GC_proc_buf_size = INITIAL_BUF_SZ; + STATIC char *GC_proc_buf = NULL; + STATIC int GC_proc_fd = 0; + +GC_INNER void GC_dirty_init(void) +{ + int fd; + char buf[30]; + + if (GC_bytes_allocd != 0 || GC_bytes_allocd_before_gc != 0) { + memset(GC_written_pages, 0xff, sizeof(page_hash_table)); + if (GC_print_stats == VERBOSE) + GC_log_printf("Allocated bytes:%lu:all pages may have been written\n", + (unsigned long)(GC_bytes_allocd + + GC_bytes_allocd_before_gc)); + } + + sprintf(buf, "/proc/%ld", (long)getpid()); + fd = open(buf, O_RDONLY); + if (fd < 0) { + ABORT("/proc open failed"); + } + GC_proc_fd = syscall(SYS_ioctl, fd, PIOCOPENPD, 0); + close(fd); + syscall(SYS_fcntl, GC_proc_fd, F_SETFD, FD_CLOEXEC); + if (GC_proc_fd < 0) { + WARN("/proc ioctl(PIOCOPENPD) failed", 0); + return; + } + + GC_dirty_maintained = TRUE; + GC_proc_buf = GC_scratch_alloc(GC_proc_buf_size); + if (GC_proc_buf == NULL) + ABORT("Insufficient space for /proc read"); +} + +# define READ read + +GC_INNER void GC_read_dirty(void) +{ + int nmaps; + unsigned long npages; + unsigned pagesize; + ptr_t vaddr, limit; + struct prasmap * map; + char * bufp; + int i; + + BZERO(GC_grungy_pages, sizeof(GC_grungy_pages)); + bufp = GC_proc_buf; + if (READ(GC_proc_fd, bufp, GC_proc_buf_size) <= 0) { + /* Retry with larger buffer. */ + word new_size = 2 * GC_proc_buf_size; + char *new_buf; + if (GC_print_stats) + GC_err_printf("/proc read failed: GC_proc_buf_size = %lu\n", + (unsigned long)GC_proc_buf_size); + + new_buf = GC_scratch_alloc(new_size); + if (new_buf != 0) { + GC_proc_buf = bufp = new_buf; + GC_proc_buf_size = new_size; + } + if (READ(GC_proc_fd, bufp, GC_proc_buf_size) <= 0) { + WARN("Insufficient space for /proc read\n", 0); + /* Punt: */ + memset(GC_grungy_pages, 0xff, sizeof (page_hash_table)); + memset(GC_written_pages, 0xff, sizeof(page_hash_table)); + return; + } + } + + /* Copy dirty bits into GC_grungy_pages */ + nmaps = ((struct prpageheader *)bufp) -> pr_nmap; +# ifdef DEBUG_DIRTY_BITS + GC_log_printf("Proc VDB read: pr_nmap= %u, pr_npage= %lu\n", + nmaps, ((struct prpageheader *)bufp)->pr_npage); + +# endif + bufp += sizeof(struct prpageheader); + for (i = 0; i < nmaps; i++) { + map = (struct prasmap *)bufp; + vaddr = (ptr_t)(map -> pr_vaddr); + npages = map -> pr_npage; + pagesize = map -> pr_pagesize; +# ifdef DEBUG_DIRTY_BITS + GC_log_printf( + "pr_vaddr= %p, npage= %lu, mflags= 0x%x, pagesize= 0x%x\n", + vaddr, npages, map->pr_mflags, pagesize); +# endif + + bufp += sizeof(struct prasmap); + limit = vaddr + pagesize * npages; + for (; vaddr < limit; vaddr += pagesize) { + if ((*bufp++) & PG_MODIFIED) { + register struct hblk * h; + ptr_t next_vaddr = vaddr + pagesize; +# ifdef DEBUG_DIRTY_BITS + GC_log_printf("dirty page at: %p\n", vaddr); +# endif + for (h = (struct hblk *)vaddr; (ptr_t)h < next_vaddr; h++) { + register word index = PHT_HASH(h); + set_pht_entry_from_index(GC_grungy_pages, index); + } + } + } + bufp = (char *)(((word)bufp + (sizeof(long)-1)) & ~(sizeof(long)-1)); + } +# ifdef DEBUG_DIRTY_BITS + GC_log_printf("Proc VDB read done.\n"); +# endif + + /* Update GC_written_pages. */ + GC_or_pages(GC_written_pages, GC_grungy_pages); +} + +# undef READ +#endif /* PROC_VDB */ + +#ifdef PCR_VDB + +# include "vd/PCR_VD.h" + +# define NPAGES (32*1024) /* 128 MB */ + +PCR_VD_DB GC_grungy_bits[NPAGES]; + +STATIC ptr_t GC_vd_base = NULL; + /* Address corresponding to GC_grungy_bits[0] */ + /* HBLKSIZE aligned. */ + +GC_INNER void GC_dirty_init(void) +{ + GC_dirty_maintained = TRUE; + /* For the time being, we assume the heap generally grows up */ + GC_vd_base = GC_heap_sects[0].hs_start; + if (GC_vd_base == 0) { + ABORT("Bad initial heap segment"); + } + if (PCR_VD_Start(HBLKSIZE, GC_vd_base, NPAGES*HBLKSIZE) + != PCR_ERes_okay) { + ABORT("Dirty bit initialization failed"); + } +} + +GC_INNER void GC_read_dirty(void) +{ + /* lazily enable dirty bits on newly added heap sects */ + { + static int onhs = 0; + int nhs = GC_n_heap_sects; + for(; onhs < nhs; onhs++) { + PCR_VD_WriteProtectEnable( + GC_heap_sects[onhs].hs_start, + GC_heap_sects[onhs].hs_bytes ); + } + } + + if (PCR_VD_Clear(GC_vd_base, NPAGES*HBLKSIZE, GC_grungy_bits) + != PCR_ERes_okay) { + ABORT("Dirty bit read failed"); + } +} + +GC_INNER GC_bool GC_page_was_dirty(struct hblk *h) +{ + if((ptr_t)h < GC_vd_base || (ptr_t)h >= GC_vd_base + NPAGES*HBLKSIZE) { + return(TRUE); + } + return(GC_grungy_bits[h - (struct hblk *)GC_vd_base] & PCR_VD_DB_dirtyBit); +} + +/*ARGSUSED*/ +GC_INNER void GC_remove_protection(struct hblk *h, word nblocks, + GC_bool is_ptrfree) +{ + PCR_VD_WriteProtectDisable(h, nblocks*HBLKSIZE); + PCR_VD_WriteProtectEnable(h, nblocks*HBLKSIZE); +} + +#endif /* PCR_VDB */ + +#if defined(MPROTECT_VDB) && defined(DARWIN) +/* The following sources were used as a "reference" for this exception + handling code: + 1. Apple's mach/xnu documentation + 2. Timothy J. Wood's "Mach Exception Handlers 101" post to the + omnigroup's macosx-dev list. + www.omnigroup.com/mailman/archive/macosx-dev/2000-June/014178.html + 3. macosx-nat.c from Apple's GDB source code. +*/ + +/* The bug that caused all this trouble should now be fixed. This should + eventually be removed if all goes well. */ + +/* #define BROKEN_EXCEPTION_HANDLING */ + +#include +#include +#include +#include +#include +#include + +/* These are not defined in any header, although they are documented */ +extern boolean_t +exc_server(mach_msg_header_t *, mach_msg_header_t *); + +extern kern_return_t +exception_raise(mach_port_t, mach_port_t, mach_port_t, exception_type_t, + exception_data_t, mach_msg_type_number_t); + +extern kern_return_t +exception_raise_state(mach_port_t, mach_port_t, mach_port_t, exception_type_t, + exception_data_t, mach_msg_type_number_t, + thread_state_flavor_t*, thread_state_t, + mach_msg_type_number_t, thread_state_t, + mach_msg_type_number_t*); + +extern kern_return_t +exception_raise_state_identity(mach_port_t, mach_port_t, mach_port_t, + exception_type_t, exception_data_t, + mach_msg_type_number_t, thread_state_flavor_t*, + thread_state_t, mach_msg_type_number_t, + thread_state_t, mach_msg_type_number_t*); + +GC_API_OSCALL kern_return_t +catch_exception_raise(mach_port_t exception_port, mach_port_t thread, + mach_port_t task, exception_type_t exception, + exception_data_t code, mach_msg_type_number_t code_count); + +/* These should never be called, but just in case... */ +GC_API_OSCALL kern_return_t +catch_exception_raise_state(mach_port_name_t exception_port, int exception, + exception_data_t code, + mach_msg_type_number_t codeCnt, int flavor, + thread_state_t old_state, int old_stateCnt, + thread_state_t new_state, int new_stateCnt) +{ + ABORT("Unexpected catch_exception_raise_state invocation"); + return(KERN_INVALID_ARGUMENT); +} + +GC_API_OSCALL kern_return_t +catch_exception_raise_state_identity(mach_port_name_t exception_port, + mach_port_t thread, mach_port_t task, + int exception, exception_data_t code, + mach_msg_type_number_t codeCnt, int flavor, + thread_state_t old_state, int old_stateCnt, + thread_state_t new_state, int new_stateCnt) +{ + ABORT("Unexpected catch_exception_raise_state_identity invocation"); + return(KERN_INVALID_ARGUMENT); +} + +#define MAX_EXCEPTION_PORTS 16 + +static struct { + mach_msg_type_number_t count; + exception_mask_t masks[MAX_EXCEPTION_PORTS]; + exception_handler_t ports[MAX_EXCEPTION_PORTS]; + exception_behavior_t behaviors[MAX_EXCEPTION_PORTS]; + thread_state_flavor_t flavors[MAX_EXCEPTION_PORTS]; +} GC_old_exc_ports; + +STATIC struct { + void (*volatile os_callback[3])(void); + mach_port_t exception; +# if defined(THREADS) + mach_port_t reply; +# endif +} GC_ports = { + { + /* This is to prevent stripping these routines as dead. */ + (void (*)(void))catch_exception_raise, + (void (*)(void))catch_exception_raise_state, + (void (*)(void))catch_exception_raise_state_identity + }, + 0 +}; + +typedef struct { + mach_msg_header_t head; +} GC_msg_t; + +typedef enum { + GC_MP_NORMAL, + GC_MP_DISCARDING, + GC_MP_STOPPED +} GC_mprotect_state_t; + +#ifdef THREADS + /* FIXME: 1 and 2 seem to be safe to use in the msgh_id field, */ + /* but it isn't documented. Use the source and see if they */ + /* should be ok. */ +# define ID_STOP 1 +# define ID_RESUME 2 + + /* This value is only used on the reply port. */ +# define ID_ACK 3 + + STATIC GC_mprotect_state_t GC_mprotect_state = 0; + + /* The following should ONLY be called when the world is stopped. */ + STATIC void GC_mprotect_thread_notify(mach_msg_id_t id) + { + struct { + GC_msg_t msg; + mach_msg_trailer_t trailer; + } buf; + mach_msg_return_t r; + + /* remote, local */ + buf.msg.head.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND, 0); + buf.msg.head.msgh_size = sizeof(buf.msg); + buf.msg.head.msgh_remote_port = GC_ports.exception; + buf.msg.head.msgh_local_port = MACH_PORT_NULL; + buf.msg.head.msgh_id = id; + + r = mach_msg(&buf.msg.head, MACH_SEND_MSG | MACH_RCV_MSG | MACH_RCV_LARGE, + sizeof(buf.msg), sizeof(buf), GC_ports.reply, + MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); + if (r != MACH_MSG_SUCCESS) + ABORT("mach_msg failed in GC_mprotect_thread_notify"); + if (buf.msg.head.msgh_id != ID_ACK) + ABORT("Invalid ack in GC_mprotect_thread_notify"); + } + + /* Should only be called by the mprotect thread */ + STATIC void GC_mprotect_thread_reply(void) + { + GC_msg_t msg; + mach_msg_return_t r; + /* remote, local */ + + msg.head.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND, 0); + msg.head.msgh_size = sizeof(msg); + msg.head.msgh_remote_port = GC_ports.reply; + msg.head.msgh_local_port = MACH_PORT_NULL; + msg.head.msgh_id = ID_ACK; + + r = mach_msg(&msg.head, MACH_SEND_MSG, sizeof(msg), 0, MACH_PORT_NULL, + MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); + if (r != MACH_MSG_SUCCESS) + ABORT("mach_msg failed in GC_mprotect_thread_reply"); + } + + GC_INNER void GC_mprotect_stop(void) + { + GC_mprotect_thread_notify(ID_STOP); + } + + GC_INNER void GC_mprotect_resume(void) + { + GC_mprotect_thread_notify(ID_RESUME); + } + +# ifndef GC_NO_THREADS_DISCOVERY + GC_INNER void GC_darwin_register_mach_handler_thread(mach_port_t thread); +# endif + +#else + /* The compiler should optimize away any GC_mprotect_state computations */ +# define GC_mprotect_state GC_MP_NORMAL +#endif /* !THREADS */ + +STATIC void *GC_mprotect_thread(void *arg) +{ + mach_msg_return_t r; + /* These two structures contain some private kernel data. We don't */ + /* need to access any of it so we don't bother defining a proper */ + /* struct. The correct definitions are in the xnu source code. */ + struct { + mach_msg_header_t head; + char data[256]; + } reply; + struct { + mach_msg_header_t head; + mach_msg_body_t msgh_body; + char data[1024]; + } msg; + mach_msg_id_t id; + +# if defined(THREADS) && !defined(GC_NO_THREADS_DISCOVERY) + GC_darwin_register_mach_handler_thread(mach_thread_self()); +# endif + + for(;;) { + r = mach_msg(&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE | + (GC_mprotect_state == GC_MP_DISCARDING ? MACH_RCV_TIMEOUT : 0), + 0, sizeof(msg), GC_ports.exception, + GC_mprotect_state == GC_MP_DISCARDING ? 0 + : MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); + id = r == MACH_MSG_SUCCESS ? msg.head.msgh_id : -1; + +# if defined(THREADS) + if(GC_mprotect_state == GC_MP_DISCARDING) { + if(r == MACH_RCV_TIMED_OUT) { + GC_mprotect_state = GC_MP_STOPPED; + GC_mprotect_thread_reply(); + continue; + } + if(r == MACH_MSG_SUCCESS && (id == ID_STOP || id == ID_RESUME)) + ABORT("Out of order mprotect thread request"); + } +# endif /* THREADS */ + + if (r != MACH_MSG_SUCCESS) { + if (GC_print_stats) + GC_log_printf("mach_msg failed with code %d: %s\n", (int)r, + mach_error_string(r)); + ABORT("mach_msg failed"); + } + + switch(id) { +# if defined(THREADS) + case ID_STOP: + if(GC_mprotect_state != GC_MP_NORMAL) + ABORT("Called mprotect_stop when state wasn't normal"); + GC_mprotect_state = GC_MP_DISCARDING; + break; + case ID_RESUME: + if(GC_mprotect_state != GC_MP_STOPPED) + ABORT("Called mprotect_resume when state wasn't stopped"); + GC_mprotect_state = GC_MP_NORMAL; + GC_mprotect_thread_reply(); + break; +# endif /* THREADS */ + default: + /* Handle the message (calls catch_exception_raise) */ + if(!exc_server(&msg.head, &reply.head)) + ABORT("exc_server failed"); + /* Send the reply */ + r = mach_msg(&reply.head, MACH_SEND_MSG, reply.head.msgh_size, 0, + MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, + MACH_PORT_NULL); + if(r != MACH_MSG_SUCCESS) { + /* This will fail if the thread dies, but the thread */ + /* shouldn't die... */ +# ifdef BROKEN_EXCEPTION_HANDLING + GC_err_printf("mach_msg failed with %d %s while sending " + "exc reply\n", (int)r, mach_error_string(r)); +# else + ABORT("mach_msg failed while sending exception reply"); +# endif + } + } /* switch */ + } /* for(;;) */ + /* NOT REACHED */ + return NULL; +} + +/* All this SIGBUS code shouldn't be necessary. All protection faults should + be going through the mach exception handler. However, it seems a SIGBUS is + occasionally sent for some unknown reason. Even more odd, it seems to be + meaningless and safe to ignore. */ +#ifdef BROKEN_EXCEPTION_HANDLING + + /* Updates to this aren't atomic, but the SIGBUS'es seem pretty rare. */ + /* Even if this doesn't get updated property, it isn't really a problem. */ + STATIC int GC_sigbus_count = 0; + + STATIC void GC_darwin_sigbus(int num, siginfo_t *sip, void *context) + { + if (num != SIGBUS) + ABORT("Got a non-sigbus signal in the sigbus handler"); + + /* Ugh... some seem safe to ignore, but too many in a row probably means + trouble. GC_sigbus_count is reset for each mach exception that is + handled */ + if (GC_sigbus_count >= 8) { + ABORT("Got more than 8 SIGBUSs in a row!"); + } else { + GC_sigbus_count++; + WARN("Ignoring SIGBUS.\n", 0); + } + } +#endif /* BROKEN_EXCEPTION_HANDLING */ + +GC_INNER void GC_dirty_init(void) +{ + kern_return_t r; + mach_port_t me; + pthread_t thread; + pthread_attr_t attr; + exception_mask_t mask; + +# ifdef CAN_HANDLE_FORK + if (GC_handle_fork) { + /* To both support GC incremental mode and GC functions usage in */ + /* the forked child, pthread_atfork should be used to install */ + /* handlers that switch off GC_dirty_maintained in the child */ + /* gracefully (unprotecting all pages and clearing */ + /* GC_mach_handler_thread). For now, we just disable incremental */ + /* mode if fork() handling is requested by the client. */ + if (GC_print_stats) + GC_log_printf( + "GC incremental mode disabled since fork() handling requested\n"); + return; + } +# endif + + if (GC_print_stats == VERBOSE) + GC_log_printf( + "Initializing mach/darwin mprotect virtual dirty bit implementation\n"); +# ifdef BROKEN_EXCEPTION_HANDLING + WARN("Enabling workarounds for various darwin " + "exception handling bugs.\n", 0); +# endif + GC_dirty_maintained = TRUE; + if (GC_page_size % HBLKSIZE != 0) { + ABORT("Page size not multiple of HBLKSIZE"); + } + + GC_task_self = me = mach_task_self(); + + r = mach_port_allocate(me, MACH_PORT_RIGHT_RECEIVE, &GC_ports.exception); + if (r != KERN_SUCCESS) + ABORT("mach_port_allocate failed (exception port)"); + + r = mach_port_insert_right(me, GC_ports.exception, GC_ports.exception, + MACH_MSG_TYPE_MAKE_SEND); + if (r != KERN_SUCCESS) + ABORT("mach_port_insert_right failed (exception port)"); + +# if defined(THREADS) + r = mach_port_allocate(me, MACH_PORT_RIGHT_RECEIVE, &GC_ports.reply); + if(r != KERN_SUCCESS) + ABORT("mach_port_allocate failed (reply port)"); +# endif + + /* The exceptions we want to catch */ + mask = EXC_MASK_BAD_ACCESS; + + r = task_get_exception_ports(me, mask, GC_old_exc_ports.masks, + &GC_old_exc_ports.count, GC_old_exc_ports.ports, + GC_old_exc_ports.behaviors, + GC_old_exc_ports.flavors); + if (r != KERN_SUCCESS) + ABORT("task_get_exception_ports failed"); + + r = task_set_exception_ports(me, mask, GC_ports.exception, EXCEPTION_DEFAULT, + GC_MACH_THREAD_STATE); + if (r != KERN_SUCCESS) + ABORT("task_set_exception_ports failed"); + if (pthread_attr_init(&attr) != 0) + ABORT("pthread_attr_init failed"); + if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0) + ABORT("pthread_attr_setdetachedstate failed"); + +# undef pthread_create + /* This will call the real pthread function, not our wrapper */ + if (pthread_create(&thread, &attr, GC_mprotect_thread, NULL) != 0) + ABORT("pthread_create failed"); + pthread_attr_destroy(&attr); + + /* Setup the sigbus handler for ignoring the meaningless SIGBUSs */ +# ifdef BROKEN_EXCEPTION_HANDLING + { + struct sigaction sa, oldsa; + sa.sa_handler = (SIG_HNDLR_PTR)GC_darwin_sigbus; + sigemptyset(&sa.sa_mask); + sa.sa_flags = SA_RESTART|SA_SIGINFO; + if (sigaction(SIGBUS, &sa, &oldsa) < 0) + ABORT("sigaction failed"); + if ((SIG_HNDLR_PTR)oldsa.sa_handler != SIG_DFL) { + if (GC_print_stats == VERBOSE) + GC_err_printf("Replaced other SIGBUS handler\n"); + } + } +# endif /* BROKEN_EXCEPTION_HANDLING */ +} + +/* The source code for Apple's GDB was used as a reference for the */ +/* exception forwarding code. This code is similar to be GDB code only */ +/* because there is only one way to do it. */ +STATIC kern_return_t GC_forward_exception(mach_port_t thread, mach_port_t task, + exception_type_t exception, + exception_data_t data, + mach_msg_type_number_t data_count) +{ + unsigned int i; + kern_return_t r; + mach_port_t port; + exception_behavior_t behavior; + thread_state_flavor_t flavor; + + thread_state_data_t thread_state; + mach_msg_type_number_t thread_state_count = THREAD_STATE_MAX; + + for (i=0; i < GC_old_exc_ports.count; i++) + if (GC_old_exc_ports.masks[i] & (1 << exception)) + break; + if (i == GC_old_exc_ports.count) + ABORT("No handler for exception!"); + + port = GC_old_exc_ports.ports[i]; + behavior = GC_old_exc_ports.behaviors[i]; + flavor = GC_old_exc_ports.flavors[i]; + + if (behavior == EXCEPTION_STATE || behavior == EXCEPTION_STATE_IDENTITY) { + r = thread_get_state(thread, flavor, thread_state, &thread_state_count); + if(r != KERN_SUCCESS) + ABORT("thread_get_state failed in forward_exception"); + } + + switch(behavior) { + case EXCEPTION_STATE: + r = exception_raise_state(port, thread, task, exception, data, data_count, + &flavor, thread_state, thread_state_count, + thread_state, &thread_state_count); + break; + case EXCEPTION_STATE_IDENTITY: + r = exception_raise_state_identity(port, thread, task, exception, data, + data_count, &flavor, thread_state, + thread_state_count, thread_state, + &thread_state_count); + break; + /* case EXCEPTION_DEFAULT: */ /* default signal handlers */ + default: /* user-supplied signal handlers */ + r = exception_raise(port, thread, task, exception, data, data_count); + } + + if (behavior == EXCEPTION_STATE || behavior == EXCEPTION_STATE_IDENTITY) { + r = thread_set_state(thread, flavor, thread_state, thread_state_count); + if (r != KERN_SUCCESS) + ABORT("thread_set_state failed in forward_exception"); + } + return r; +} + +#define FWD() GC_forward_exception(thread, task, exception, code, code_count) + +#ifdef ARM32 +# define DARWIN_EXC_STATE ARM_EXCEPTION_STATE +# define DARWIN_EXC_STATE_COUNT ARM_EXCEPTION_STATE_COUNT +# define DARWIN_EXC_STATE_T arm_exception_state_t +# define DARWIN_EXC_STATE_DAR THREAD_FLD(far) +#elif defined(POWERPC) +# if CPP_WORDSZ == 32 +# define DARWIN_EXC_STATE PPC_EXCEPTION_STATE +# define DARWIN_EXC_STATE_COUNT PPC_EXCEPTION_STATE_COUNT +# define DARWIN_EXC_STATE_T ppc_exception_state_t +# else +# define DARWIN_EXC_STATE PPC_EXCEPTION_STATE64 +# define DARWIN_EXC_STATE_COUNT PPC_EXCEPTION_STATE64_COUNT +# define DARWIN_EXC_STATE_T ppc_exception_state64_t +# endif +# define DARWIN_EXC_STATE_DAR THREAD_FLD(dar) +#elif defined(I386) || defined(X86_64) +# if CPP_WORDSZ == 32 +# define DARWIN_EXC_STATE x86_EXCEPTION_STATE32 +# define DARWIN_EXC_STATE_COUNT x86_EXCEPTION_STATE32_COUNT +# define DARWIN_EXC_STATE_T x86_exception_state32_t +# else +# define DARWIN_EXC_STATE x86_EXCEPTION_STATE64 +# define DARWIN_EXC_STATE_COUNT x86_EXCEPTION_STATE64_COUNT +# define DARWIN_EXC_STATE_T x86_exception_state64_t +# endif +# define DARWIN_EXC_STATE_DAR THREAD_FLD(faultvaddr) +#else +# error FIXME for non-arm/ppc/x86 darwin +#endif + +/* This violates the namespace rules but there isn't anything that can */ +/* be done about it. The exception handling stuff is hard coded to */ +/* call this. catch_exception_raise, catch_exception_raise_state and */ +/* and catch_exception_raise_state_identity are called from OS. */ +GC_API_OSCALL kern_return_t +catch_exception_raise(mach_port_t exception_port, mach_port_t thread, + mach_port_t task, exception_type_t exception, + exception_data_t code, mach_msg_type_number_t code_count) +{ + kern_return_t r; + char *addr; + struct hblk *h; + unsigned int i; + thread_state_flavor_t flavor = DARWIN_EXC_STATE; + mach_msg_type_number_t exc_state_count = DARWIN_EXC_STATE_COUNT; + DARWIN_EXC_STATE_T exc_state; + + if (exception != EXC_BAD_ACCESS || code[0] != KERN_PROTECTION_FAILURE) { +# ifdef DEBUG_EXCEPTION_HANDLING + /* We aren't interested, pass it on to the old handler */ + GC_log_printf("Exception: 0x%x Code: 0x%x 0x%x in catch...\n", + exception, code_count > 0 ? code[0] : -1, + code_count > 1 ? code[1] : -1); +# endif + return FWD(); + } + + r = thread_get_state(thread, flavor, (natural_t*)&exc_state, + &exc_state_count); + if(r != KERN_SUCCESS) { + /* The thread is supposed to be suspended while the exception */ + /* handler is called. This shouldn't fail. */ +# ifdef BROKEN_EXCEPTION_HANDLING + GC_err_printf("thread_get_state failed in catch_exception_raise\n"); + return KERN_SUCCESS; +# else + ABORT("thread_get_state failed in catch_exception_raise"); +# endif + } + + /* This is the address that caused the fault */ + addr = (char*) exc_state.DARWIN_EXC_STATE_DAR; + if (HDR(addr) == 0) { + /* Ugh... just like the SIGBUS problem above, it seems we get */ + /* a bogus KERN_PROTECTION_FAILURE every once and a while. We wait */ + /* till we get a bunch in a row before doing anything about it. */ + /* If a "real" fault ever occurs it'll just keep faulting over and */ + /* over and we'll hit the limit pretty quickly. */ +# ifdef BROKEN_EXCEPTION_HANDLING + static char *last_fault; + static int last_fault_count; + + if(addr != last_fault) { + last_fault = addr; + last_fault_count = 0; + } + if(++last_fault_count < 32) { + if(last_fault_count == 1) + WARN("Ignoring KERN_PROTECTION_FAILURE at %p\n", addr); + return KERN_SUCCESS; + } + + GC_err_printf( + "Unexpected KERN_PROTECTION_FAILURE at %p; aborting...\n", addr); + /* Can't pass it along to the signal handler because that is */ + /* ignoring SIGBUS signals. We also shouldn't call ABORT here as */ + /* signals don't always work too well from the exception handler. */ + exit(EXIT_FAILURE); +# else /* BROKEN_EXCEPTION_HANDLING */ + /* Pass it along to the next exception handler + (which should call SIGBUS/SIGSEGV) */ + return FWD(); +# endif /* !BROKEN_EXCEPTION_HANDLING */ + } + +# ifdef BROKEN_EXCEPTION_HANDLING + /* Reset the number of consecutive SIGBUSs */ + GC_sigbus_count = 0; +# endif + + if (GC_mprotect_state == GC_MP_NORMAL) { /* common case */ + h = (struct hblk*)((word)addr & ~(GC_page_size-1)); + UNPROTECT(h, GC_page_size); + for (i = 0; i < divHBLKSZ(GC_page_size); i++) { + register int index = PHT_HASH(h+i); + async_set_pht_entry_from_index(GC_dirty_pages, index); + } + } else if (GC_mprotect_state == GC_MP_DISCARDING) { + /* Lie to the thread for now. No sense UNPROTECT()ing the memory + when we're just going to PROTECT() it again later. The thread + will just fault again once it resumes */ + } else { + /* Shouldn't happen, i don't think */ + GC_err_printf("KERN_PROTECTION_FAILURE while world is stopped\n"); + return FWD(); + } + return KERN_SUCCESS; +} +#undef FWD + +#ifndef NO_DESC_CATCH_EXCEPTION_RAISE + /* These symbols should have REFERENCED_DYNAMICALLY (0x10) bit set to */ + /* let strip know they are not to be stripped. */ + __asm__(".desc _catch_exception_raise, 0x10"); + __asm__(".desc _catch_exception_raise_state, 0x10"); + __asm__(".desc _catch_exception_raise_state_identity, 0x10"); +#endif + +#endif /* DARWIN && MPROTECT_VDB */ + +#ifndef HAVE_INCREMENTAL_PROTECTION_NEEDS + GC_API int GC_CALL GC_incremental_protection_needs(void) + { + return GC_PROTECTS_NONE; + } +#endif /* !HAVE_INCREMENTAL_PROTECTION_NEEDS */ + +#ifdef ECOS + /* Undo sbrk() redirection. */ +# undef sbrk +#endif + +/* If value is non-zero then allocate executable memory. */ +GC_API void GC_CALL GC_set_pages_executable(int value) +{ + GC_ASSERT(!GC_is_initialized); + /* Even if IGNORE_PAGES_EXECUTABLE is defined, GC_pages_executable is */ + /* touched here to prevent a compiler warning. */ + GC_pages_executable = (GC_bool)(value != 0); +} + +/* Returns non-zero if the GC-allocated memory is executable. */ +/* GC_get_pages_executable is defined after all the places */ +/* where GC_get_pages_executable is undefined. */ +GC_API int GC_CALL GC_get_pages_executable(void) +{ +# ifdef IGNORE_PAGES_EXECUTABLE + return 1; /* Always allocate executable memory. */ +# else + return (int)GC_pages_executable; +# endif +} + +/* Call stack save code for debugging. Should probably be in */ +/* mach_dep.c, but that requires reorganization. */ + +/* I suspect the following works for most X86 *nix variants, so */ +/* long as the frame pointer is explicitly stored. In the case of gcc, */ +/* compiler flags (e.g. -fomit-frame-pointer) determine whether it is. */ +#if defined(I386) && defined(LINUX) && defined(SAVE_CALL_CHAIN) +# include + + struct frame { + struct frame *fr_savfp; + long fr_savpc; + long fr_arg[NARGS]; /* All the arguments go here. */ + }; +#endif + +#if defined(SPARC) +# if defined(LINUX) +# include + + struct frame { + long fr_local[8]; + long fr_arg[6]; + struct frame *fr_savfp; + long fr_savpc; +# ifndef __arch64__ + char *fr_stret; +# endif + long fr_argd[6]; + long fr_argx[0]; + }; +# elif defined (DRSNX) +# include +# elif defined(OPENBSD) +# include +# elif defined(FREEBSD) || defined(NETBSD) +# include +# else +# include +# endif +# if NARGS > 6 +# error We only know how to get the first 6 arguments +# endif +#endif /* SPARC */ + +#ifdef NEED_CALLINFO +/* Fill in the pc and argument information for up to NFRAMES of my */ +/* callers. Ignore my frame and my callers frame. */ + +#ifdef LINUX +# include +#endif + +#endif /* NEED_CALLINFO */ + +#if defined(GC_HAVE_BUILTIN_BACKTRACE) +# ifdef _MSC_VER +# include "private/msvc_dbg.h" +# else +# include +# endif +#endif + +#ifdef SAVE_CALL_CHAIN + +#if NARGS == 0 && NFRAMES % 2 == 0 /* No padding */ \ + && defined(GC_HAVE_BUILTIN_BACKTRACE) + +#ifdef REDIRECT_MALLOC + /* Deal with possible malloc calls in backtrace by omitting */ + /* the infinitely recursing backtrace. */ +# ifdef THREADS + __thread /* If your compiler doesn't understand this */ + /* you could use something like pthread_getspecific. */ +# endif + GC_in_save_callers = FALSE; +#endif + +GC_INNER void GC_save_callers(struct callinfo info[NFRAMES]) +{ + void * tmp_info[NFRAMES + 1]; + int npcs, i; +# define IGNORE_FRAMES 1 + + /* We retrieve NFRAMES+1 pc values, but discard the first, since it */ + /* points to our own frame. */ +# ifdef REDIRECT_MALLOC + if (GC_in_save_callers) { + info[0].ci_pc = (word)(&GC_save_callers); + for (i = 1; i < NFRAMES; ++i) info[i].ci_pc = 0; + return; + } + GC_in_save_callers = TRUE; +# endif + GC_STATIC_ASSERT(sizeof(struct callinfo) == sizeof(void *)); + npcs = backtrace((void **)tmp_info, NFRAMES + IGNORE_FRAMES); + BCOPY(tmp_info+IGNORE_FRAMES, info, (npcs - IGNORE_FRAMES) * sizeof(void *)); + for (i = npcs - IGNORE_FRAMES; i < NFRAMES; ++i) info[i].ci_pc = 0; +# ifdef REDIRECT_MALLOC + GC_in_save_callers = FALSE; +# endif +} + +#else /* No builtin backtrace; do it ourselves */ + +#if (defined(OPENBSD) || defined(NETBSD) || defined(FREEBSD)) && defined(SPARC) +# define FR_SAVFP fr_fp +# define FR_SAVPC fr_pc +#else +# define FR_SAVFP fr_savfp +# define FR_SAVPC fr_savpc +#endif + +#if defined(SPARC) && (defined(__arch64__) || defined(__sparcv9)) +# define BIAS 2047 +#else +# define BIAS 0 +#endif + +GC_INNER void GC_save_callers(struct callinfo info[NFRAMES]) +{ + struct frame *frame; + struct frame *fp; + int nframes = 0; +# ifdef I386 + /* We assume this is turned on only with gcc as the compiler. */ + asm("movl %%ebp,%0" : "=r"(frame)); + fp = frame; +# else + frame = (struct frame *)GC_save_regs_in_stack(); + fp = (struct frame *)((long) frame -> FR_SAVFP + BIAS); +#endif + + for (; (!(fp HOTTER_THAN frame) && !(GC_stackbottom HOTTER_THAN (ptr_t)fp) + && (nframes < NFRAMES)); + fp = (struct frame *)((long) fp -> FR_SAVFP + BIAS), nframes++) { + register int i; + + info[nframes].ci_pc = fp->FR_SAVPC; +# if NARGS > 0 + for (i = 0; i < NARGS; i++) { + info[nframes].ci_arg[i] = ~(fp->fr_arg[i]); + } +# endif /* NARGS > 0 */ + } + if (nframes < NFRAMES) info[nframes].ci_pc = 0; +} + +#endif /* No builtin backtrace */ + +#endif /* SAVE_CALL_CHAIN */ + +#ifdef NEED_CALLINFO + +/* Print info to stderr. We do NOT hold the allocation lock */ +GC_INNER void GC_print_callers(struct callinfo info[NFRAMES]) +{ + int i; + static int reentry_count = 0; + GC_bool stop = FALSE; + DCL_LOCK_STATE; + + /* FIXME: This should probably use a different lock, so that we */ + /* become callable with or without the allocation lock. */ + LOCK(); + ++reentry_count; + UNLOCK(); + +# if NFRAMES == 1 + GC_err_printf("\tCaller at allocation:\n"); +# else + GC_err_printf("\tCall chain at allocation:\n"); +# endif + for (i = 0; i < NFRAMES && !stop; i++) { + if (info[i].ci_pc == 0) break; +# if NARGS > 0 + { + int j; + + GC_err_printf("\t\targs: "); + for (j = 0; j < NARGS; j++) { + if (j != 0) GC_err_printf(", "); + GC_err_printf("%d (0x%X)", ~(info[i].ci_arg[j]), + ~(info[i].ci_arg[j])); + } + GC_err_printf("\n"); + } +# endif + if (reentry_count > 1) { + /* We were called during an allocation during */ + /* a previous GC_print_callers call; punt. */ + GC_err_printf("\t\t##PC##= 0x%lx\n", info[i].ci_pc); + continue; + } + { +# ifdef LINUX + FILE *pipe; +# endif +# if defined(GC_HAVE_BUILTIN_BACKTRACE) \ + && !defined(GC_BACKTRACE_SYMBOLS_BROKEN) + char **sym_name = + backtrace_symbols((void **)(&(info[i].ci_pc)), 1); + char *name = sym_name[0]; +# else + char buf[40]; + char *name = buf; + sprintf(buf, "##PC##= 0x%lx", info[i].ci_pc); +# endif +# if defined(LINUX) && !defined(SMALL_CONFIG) + /* Try for a line number. */ + { +# define EXE_SZ 100 + static char exe_name[EXE_SZ]; +# define CMD_SZ 200 + char cmd_buf[CMD_SZ]; +# define RESULT_SZ 200 + static char result_buf[RESULT_SZ]; + size_t result_len; + char *old_preload; +# define PRELOAD_SZ 200 + char preload_buf[PRELOAD_SZ]; + static GC_bool found_exe_name = FALSE; + static GC_bool will_fail = FALSE; + int ret_code; + /* Try to get it via a hairy and expensive scheme. */ + /* First we get the name of the executable: */ + if (will_fail) goto out; + if (!found_exe_name) { + ret_code = readlink("/proc/self/exe", exe_name, EXE_SZ); + if (ret_code < 0 || ret_code >= EXE_SZ + || exe_name[0] != '/') { + will_fail = TRUE; /* Don't try again. */ + goto out; + } + exe_name[ret_code] = '\0'; + found_exe_name = TRUE; + } + /* Then we use popen to start addr2line -e */ + /* There are faster ways to do this, but hopefully this */ + /* isn't time critical. */ + sprintf(cmd_buf, "/usr/bin/addr2line -f -e %s 0x%lx", exe_name, + (unsigned long)info[i].ci_pc); + old_preload = GETENV("LD_PRELOAD"); + if (0 != old_preload) { + if (strlen (old_preload) >= PRELOAD_SZ) { + will_fail = TRUE; + goto out; + } + strcpy (preload_buf, old_preload); + unsetenv ("LD_PRELOAD"); + } + pipe = popen(cmd_buf, "r"); + if (0 != old_preload + && 0 != setenv ("LD_PRELOAD", preload_buf, 0)) { + WARN("Failed to reset LD_PRELOAD\n", 0); + } + if (pipe == NULL + || (result_len = fread(result_buf, 1, RESULT_SZ - 1, pipe)) + == 0) { + if (pipe != NULL) pclose(pipe); + will_fail = TRUE; + goto out; + } + if (result_buf[result_len - 1] == '\n') --result_len; + result_buf[result_len] = 0; + if (result_buf[0] == '?' + || (result_buf[result_len-2] == ':' + && result_buf[result_len-1] == '0')) { + pclose(pipe); + goto out; + } + /* Get rid of embedded newline, if any. Test for "main" */ + { + char * nl = strchr(result_buf, '\n'); + if (nl != NULL && nl < result_buf + result_len) { + *nl = ':'; + } + if (strncmp(result_buf, "main", nl - result_buf) == 0) { + stop = TRUE; + } + } + if (result_len < RESULT_SZ - 25) { + /* Add in hex address */ + sprintf(result_buf + result_len, " [0x%lx]", + (unsigned long)info[i].ci_pc); + } + name = result_buf; + pclose(pipe); + out:; + } +# endif /* LINUX */ + GC_err_printf("\t\t%s\n", name); +# if defined(GC_HAVE_BUILTIN_BACKTRACE) \ + && !defined(GC_BACKTRACE_SYMBOLS_BROKEN) + free(sym_name); /* May call GC_free; that's OK */ +# endif + } + } + LOCK(); + --reentry_count; + UNLOCK(); +} + +#endif /* NEED_CALLINFO */ + +#if defined(LINUX) && defined(__ELF__) && !defined(SMALL_CONFIG) + /* Dump /proc/self/maps to GC_stderr, to enable looking up names for */ + /* addresses in FIND_LEAK output. */ + void GC_print_address_map(void) + { + char *maps; + + GC_err_printf("---------- Begin address map ----------\n"); + maps = GC_get_maps(); + GC_err_puts(maps != NULL ? maps : "Failed to get map!\n"); + GC_err_printf("---------- End address map ----------\n"); + } +#endif /* LINUX && ELF */