Merge pull request #2417 from razzfazz/guard_substr

handle path stripping correctly for root of watched tree

diff --combined mcs/class/System/System.IO/KeventWatcher.cs
index 7570bd68915a6bae106f07711448e995918d1d32,6875dbdc476ba75d94cb00d9c93aeef7c45295b2..778671764ea91a8f8b9bcc563e60b0b68d9d0fdd
--- 1/mcs/class/System/System.IO/KeventWatcher.cs
--- 2/mcs/class/System/System.IO/KeventWatcher.cs
+++ b/mcs/class/System/System.IO/KeventWatcher.cs
@@@ -150,7 -150,7 +150,7 @@@ namespace System.IO 
        [StructLayout(LayoutKind.Sequential)]
        struct timespec {
                public IntPtr tv_sec;
 -              public IntPtr tv_usec;
 +              public IntPtr tv_nsec;
        }
  
        class PathData
@@@ -300,14 -300,11 +300,14 @@@
                        else
                                fullPathNoLastSlash = fsw.FullPath;
                                
 -                      // GetFilenameFromFd() returns the *realpath* which can be different than fsw.FullPath because symlinks.
 +                      // realpath() returns the *realpath* which can be different than fsw.FullPath because symlinks.
                        // If so, introduce a fixup step.
 -                      int fd = open (fullPathNoLastSlash, O_EVTONLY, 0);
 -                      var resolvedFullPath = GetFilenameFromFd (fd);
 -                      close (fd);
 +                      var sb = new StringBuilder (__DARWIN_MAXPATHLEN);
 +                      if (realpath(fsw.FullPath, sb) == IntPtr.Zero) {
 +                              var errMsg = String.Format ("realpath({0}) failed, error code = '{1}'", fsw.FullPath, Marshal.GetLastWin32Error ());
 +                              throw new IOException (errMsg);
 +                      }
 +                      var resolvedFullPath = sb.ToString();
  
                        if (resolvedFullPath != fullPathNoLastSlash)
                                fixupPath = resolvedFullPath;
@@@ -316,21 -313,14 +316,21 @@@
  
                        Scan (fullPathNoLastSlash, false, ref initialFds);
  
 -                      var immediate_timeout = new timespec { tv_sec = (IntPtr)0, tv_usec = (IntPtr)0 };
 +                      var immediate_timeout = new timespec { tv_sec = (IntPtr)0, tv_nsec = (IntPtr)0 };
                        var eventBuffer = new kevent[0]; // we don't want to take any events from the queue at this point
                        var changes = CreateChangeList (ref initialFds);
  
 -                      int numEvents = kevent (conn, changes, changes.Length, eventBuffer, eventBuffer.Length, ref immediate_timeout);
 +                      int numEvents;
 +                      int errno = 0;
 +                      do {
 +                              numEvents = kevent (conn, changes, changes.Length, eventBuffer, eventBuffer.Length, ref immediate_timeout);
 +                              if (numEvents == -1) {
 +                                      errno = Marshal.GetLastWin32Error ();
 +                              }
 +                      } while (numEvents == -1 && errno == EINTR);
  
                        if (numEvents == -1) {
 -                              var errMsg = String.Format ("kevent() error at initial event registration, error code = '{0}'", Marshal.GetLastWin32Error ());
 +                              var errMsg = String.Format ("kevent() error at initial event registration, error code = '{0}'", errno);
                                throw new IOException (errMsg);
                        }
                }
@@@ -394,10 -384,9 +394,10 @@@
                                        // Stop () signals us to stop by closing the connection
                                        if (requestStop)
                                                break;
 -                                      if (++retries == 3)
 +                                      int errno = Marshal.GetLastWin32Error ();
 +                                      if (errno != EINTR && ++retries == 3)
                                                throw new IOException (String.Format (
 -                                                      "persistent kevent() error, error code = '{0}'", Marshal.GetLastWin32Error ()));
 +                                                      "persistent kevent() error, error code = '{0}'", errno));
  
                                        continue;
                                }
@@@ -617,14 -606,14 +617,14 @@@
                                return;
  
                        // e.Name
-                       string name = path.Substring (fullPathNoLastSlash.Length + 1); 
+                       string name = (path.Length > fullPathNoLastSlash.Length) ? path.Substring (fullPathNoLastSlash.Length + 1) : String.Empty;
  
                        // only post events that match filter pattern. check both old and new paths for renames
                        if (!fsw.Pattern.IsMatch (path) && (newPath == null || !fsw.Pattern.IsMatch (newPath)))
                                return;
                                
                        if (action == FileAction.RenamedNewName) {
-                               string newName = newPath.Substring (fullPathNoLastSlash.Length + 1);
+                               string newName = (newPath.Length > fullPathNoLastSlash.Length) ? newPath.Substring (fullPathNoLastSlash.Length + 1) : String.Empty;
                                renamed = new RenamedEventArgs (WatcherChangeTypes.Renamed, fsw.Path, newName, name);
                        }
                                
@@@ -657,7 -646,6 +657,7 @@@
                const int O_EVTONLY = 0x8000;
                const int F_GETPATH = 50;
                const int __DARWIN_MAXPATHLEN = 1024;
 +              const int EINTR = 4;
                static readonly kevent[] emptyEventList = new System.IO.kevent[0];
                int maxFds = Int32.MaxValue;
  
@@@ -677,22 -665,19 +677,22 @@@
                string fixupPath = null;
                string fullPathNoLastSlash = null;
  
 -              [DllImport ("libc", EntryPoint="fcntl", CharSet=CharSet.Auto, SetLastError=true)]
 +              [DllImport ("libc", CharSet=CharSet.Auto, SetLastError=true)]
                static extern int fcntl (int file_names_by_descriptor, int cmd, StringBuilder sb);
  
 -              [DllImport ("libc")]
 +              [DllImport ("libc", CharSet=CharSet.Auto, SetLastError=true)]
 +              static extern IntPtr realpath (string pathname, StringBuilder sb);
 +
 +              [DllImport ("libc", SetLastError=true)]
                extern static int open (string path, int flags, int mode_t);
  
                [DllImport ("libc")]
                extern static int close (int fd);
  
 -              [DllImport ("libc")]
 +              [DllImport ("libc", SetLastError=true)]
                extern static int kqueue ();
  
 -              [DllImport ("libc")]
 +              [DllImport ("libc", SetLastError=true)]
                extern static int kevent (int kq, [In]kevent[] ev, int nchanges, [Out]kevent[] evtlist, int nevents, [In] ref timespec time);
  
                [MethodImplAttribute(MethodImplOptions.InternalCall)]