* fileio.c: Report proper errno when syscall falls.

(Finsert_file_contents): Save and restore errno,
so that report_file_error outputs the correct diagnostic.
(Fwrite_region) [CLASH_DETECTION]: Likewise.

2 files changed, 12 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 835e70f99a..282275ffa0 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2011-09-18  Paul Eggert  <[email protected]>
+
+	* fileio.c: Report proper errno when syscall falls.
+	(Finsert_file_contents): Save and restore errno,
+	so that report_file_error outputs the correct diagnostic.
+	(Fwrite_region) [CLASH_DETECTION]: Likewise.
+
 2011-09-18  Eli Zaretskii  <[email protected]>
 
 	* .gdbinit (pgx): Fix references to fields of `struct glyph'.
diff --git a/src/fileio.c b/src/fileio.c
index 08be41f9fe..e335dcf027 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -3187,6 +3187,7 @@ variable `last-coding-system-used' to the coding system actually used.  */)
   Lisp_Object p;
   EMACS_INT total = 0;
   int not_regular = 0;
+  int save_errno = 0;
   char read_buf[READ_BUF_SIZE];
   struct coding_system coding;
   char buffer[1 << 14];
@@ -3250,6 +3251,7 @@ variable `last-coding-system-used' to the coding system actually used.  */)
 #endif /* WINDOWSNT */
     {
     badopen:
+      save_errno = errno;
       if (NILP (visit))
 	report_file_error ("Opening input file", Fcons (orig_filename, Qnil));
       st.st_mtime = -1;
@@ -4281,6 +4283,7 @@ variable `last-coding-system-used' to the coding system actually used.  */)
       && current_buffer->modtime == -1)
     {
       /* If visiting nonexistent file, return nil.  */
+      errno = save_errno;
       report_file_error ("Opening input file", Fcons (orig_filename, Qnil));
     }
 
@@ -4618,7 +4621,9 @@ This calls `write-region-annotate-functions' at the start, and
       if (ret < 0)
 	{
 #ifdef CLASH_DETECTION
+	  save_errno = errno;
 	  if (!auto_saving) unlock_file (lockname);
+	  errno = save_errno;
 #endif /* CLASH_DETECTION */
 	  UNGCPRO;
 	  report_file_error ("Lseek error", Fcons (filename, Qnil));