X-Git-Url: http://wien.tomnetworks.com/gitweb/?a=blobdiff_plain;f=mono%2Fmetadata%2Frawbuffer.c;h=167d9b8391d9480767114e007cb819af3cf03467;hb=e66357c45bb0e159aa3d02276347757e75a15dd7;hp=9c1ee78c1a8459766d490f13873edeb24369b3ae;hpb=0649b90c407fc29ee8377f2c6fb42ae2c006e26a;p=mono.git

diff --git a/mono/metadata/rawbuffer.c b/mono/metadata/rawbuffer.c
index 9c1ee78c1a8..167d9b8391d 100644
--- a/mono/metadata/rawbuffer.c
+++ b/mono/metadata/rawbuffer.c
@@ -11,7 +11,9 @@
 #define USE_WIN32_API		1
 #endif
 
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 #include <errno.h>
 #ifdef USE_WIN32_API
 #include <winsock2.h>
@@ -36,7 +38,11 @@
 
 static GHashTable *mmap_map = NULL;
 static size_t alignment = 0;
+#define mono_mmap_lock() EnterCriticalSection (&mmap_mutex)
+#define mono_mmap_unlock() LeaveCriticalSection (&mmap_mutex)
 static CRITICAL_SECTION mmap_mutex;
+static gboolean make_unreadable = FALSE;
+static guint32 n_pagefaults = 0;
 
 static void
 get_alignment (void)
@@ -85,6 +91,14 @@ mono_raw_buffer_init (void)
 	mmap_map = g_hash_table_new (NULL, NULL);
 }
 
+void
+mono_raw_buffer_cleanup (void)
+{
+	g_hash_table_destroy (mmap_map);
+
+	DeleteCriticalSection (&mmap_mutex);
+}
+
 static void *
 mono_raw_buffer_load_mmap (int fd, int is_writable, guint32 base, size_t size)
 {
@@ -119,9 +133,9 @@ mono_raw_buffer_load_mmap (int fd, int is_writable, guint32 base, size_t size)
 		return 0;
 	}
 
-	EnterCriticalSection (&mmap_mutex);
+	mono_mmap_lock ();
 	g_hash_table_insert (mmap_map, ptr, GINT_TO_POINTER (mapping));
-	LeaveCriticalSection (&mmap_mutex);
+	mono_mmap_unlock ();
 	
 	return ((char *)ptr) + (base - start);
 
@@ -155,13 +169,16 @@ mono_raw_buffer_load_mmap (int fd, int is_writable, guint32 base, size_t size)
 	 * http://bugzilla.ximian.com/show_bug.cgi?id=49499
 	 * for more info.
 	 */
-	if (mprotect (ptr, end - start, prot | PROT_EXEC) != 0)
-		g_warning (G_GNUC_PRETTY_FUNCTION
-				   ": mprotect failed: %s", g_strerror (errno));
-	
-	EnterCriticalSection (&mmap_mutex);
+	mprotect (ptr, end - start, prot | PROT_EXEC);
+
+	if (make_unreadable) {
+		int res = mprotect (ptr, end - start, 0);
+		g_assert (res == 0);
+	}
+
+	mono_mmap_lock ();
 	g_hash_table_insert (mmap_map, ptr, GINT_TO_POINTER (size));
-	LeaveCriticalSection (&mmap_mutex);
+	mono_mmap_unlock ();
 
 	return ((char *)ptr) + (base - start);
 #endif
@@ -172,9 +189,9 @@ mono_raw_buffer_free_mmap (void *base)
 {
 	int value;
 
-	EnterCriticalSection (&mmap_mutex);
+	mono_mmap_lock ();
 	value = GPOINTER_TO_INT (g_hash_table_lookup (mmap_map, base));
-	LeaveCriticalSection (&mmap_mutex);
+	mono_mmap_unlock ();
 
 #ifdef USE_WIN32_API
 	UnmapViewOfFile (base);
@@ -214,9 +231,9 @@ mono_raw_buffer_update (void *buffer, size_t size)
 
 	mmap_base =  (gpointer)(ROUND_DOWN ((UINTPTR_TYPE) (buffer), alignment));
 
-	EnterCriticalSection (&mmap_mutex);
+	mono_mmap_lock ();
 	exists = g_hash_table_lookup (mmap_map, mmap_base) != NULL;
-	LeaveCriticalSection (&mmap_mutex);
+	mono_mmap_unlock ();
 	if (exists)
 		mono_raw_buffer_update_mmap (mmap_base, size);
 }
@@ -236,3 +253,90 @@ mono_raw_buffer_free (void *buffer)
 		mono_raw_buffer_free_malloc (buffer);
 }
 
+/*
+ * mono_raw_buffer_set_make_unreadable:
+ *
+ *   Set whenever to make all mmaped memory unreadable. In conjuction with a
+ * SIGSEGV handler, this is useful to find out which pages the runtime tries to read.
+ */
+void
+mono_raw_buffer_set_make_unreadable (gboolean unreadable)
+{
+	make_unreadable = unreadable;
+}
+
+typedef struct {
+	gboolean found;
+	void *ptr;
+} FindMapUserData;
+
+static void
+find_map (void *start, guint32 size, gpointer user_data)
+{
+	FindMapUserData *data = (FindMapUserData*)user_data;
+
+	if (!data->found)
+		if (((guint8*)data->ptr >= (guint8*)start) && ((guint8*)data->ptr < (guint8*)start + size))
+			data->found = TRUE;
+}
+
+/*
+ * mono_raw_buffer_is_pagefault:
+ *
+ *   Should be called from a SIGSEGV signal handler to find out whenever @ptr is
+ * within memory allocated by this module.
+ */
+gboolean
+mono_raw_buffer_is_pagefault (void *ptr)
+{
+	FindMapUserData data;
+
+	if (!make_unreadable)
+		return FALSE;
+
+	data.found = FALSE;
+	data.ptr = ptr;
+
+	mono_mmap_lock ();
+	g_hash_table_foreach (mmap_map, (GHFunc)find_map, &data);
+	mono_mmap_unlock ();
+
+	return data.found;
+}
+
+/*
+ * mono_raw_buffer_handle_pagefault:
+ *
+ *   Handle a pagefault caused by an unreadable page by making it readable again.
+ */
+void
+mono_raw_buffer_handle_pagefault (void *ptr)
+{
+#ifndef PLATFORM_WIN32
+	guint8* start = (guint8*)ROUND_DOWN (((gssize)ptr), alignment);
+	int res;
+
+	mono_mmap_lock ();
+	res = mprotect (start, alignment, PROT_READ);
+	g_assert (res == 0);
+
+	n_pagefaults ++;
+	mono_mmap_unlock ();
+#endif
+}
+
+/*
+ * mono_raw_buffer_get_n_pagefaults:
+ *
+ *   Return the number of times handle_pagefault is called.
+ * To count the number of pagefaults caused by a block of code use code like this:
+ * 
+ *  int prev_pagefaults = mono_raw_buffer_get_n_pagefaults ();
+ *  <CODE>
+ *  int new_pagefaults = mono_raw_buffer_get_n_pagefaults () - prev_pagefaults;
+ */
+guint32
+mono_raw_buffer_get_n_pagefaults (void)
+{
+	return n_pagefaults;
+}