Fix some stat-related races.

* fileio.c (Fwrite_region): Avoid race condition if a file is
removed or renamed by some other process immediately after Emacs
writes it but before Emacs stats it.  Do not assume that stat (or
fstat) succeeds.
* image.c (slurp_file): Resolve the file name with fopen + fstat
rather than stat + fopen.
(pbm_read_file) [0]: Remove unused code with stat race.
* process.c (allocate_pty) [HAVE_PTYS && !PTY_ITERATION && !PTY_OPEN]:
Remove ineffective code with stat race.

1 files changed, 0 insertions, 17 deletions

diff --git a/src/process.c b/src/process.c
index 2cbce9d28ea..d45a2c6e8e0 100644
--- a/src/process.c
+++ b/src/process.c
@@ -646,23 +646,6 @@ allocate_pty (void)
         PTY_OPEN;
 #else /* no PTY_OPEN */
         {
-          { /* Some systems name their pseudoterminals so that there are gaps in
-               the usual sequence - for example, on HP9000/S700 systems, there
-               are no pseudoterminals with names ending in 'f'.  So we wait for
-               three failures in a row before deciding that we've reached the
-               end of the ptys.  */
-            int failed_count = 0;
-            struct stat stb;
-
-            if (stat (pty_name, &stb) < 0)
-              {
-                failed_count++;
-                if (failed_count >= 3)
-                  return -1;
-              }
-            else
-              failed_count = 0;
-          }
 #  ifdef O_NONBLOCK
           fd = emacs_open (pty_name, O_RDWR | O_NONBLOCK, 0);
 #  else