A few more minor file errno-reporting bugs.

* callproc.c (Fcall_process):
* doc.c (Fsnarf_documentation):
* fileio.c (Frename_file, Fadd_name_to_file, Fmake_symbolic_link):
* process.c (set_socket_option):
Don't let a constructor trash errno.
* doc.c: Include <errno.h>.

5 files changed, 41 insertions, 8 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 62529d8d778..23334449ef3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,13 @@
+2013-07-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        A few more minor file errno-reporting bugs.
+        * callproc.c (Fcall_process):
+        * doc.c (Fsnarf_documentation):
+        * fileio.c (Frename_file, Fadd_name_to_file, Fmake_symbolic_link):
+        * process.c (set_socket_option):
+        Don't let a constructor trash errno.
+        * doc.c: Include <errno.h>.
+
 2013-07-16  Juanma Barranquero  <lekktu@gmail.com>
 
         * w32fns.c (unwind_create_tip_frame): Fix declaration.
diff --git a/src/callproc.c b/src/callproc.c
index 85ebf449e43..e0040ada609 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -405,7 +405,11 @@ usage: (call-process PROGRAM &optional INFILE DESTINATION DISPLAY &rest ARGS)  *
 
   filefd = emacs_open (SSDATA (infile), O_RDONLY, 0);
   if (filefd < 0)
-    report_file_error ("Opening process input file", DECODE_FILE (infile));
+    {
+      int open_errno = errno;
+      report_file_errno ("Opening process input file", DECODE_FILE (infile),
+                         open_errno);
+    }
 
   if (STRINGP (output_file))
     {
diff --git a/src/doc.c b/src/doc.c
index 92c7b2c6dc9..168af6da94a 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -21,6 +21,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 
+#include <errno.h>
 #include <sys/types.h>
 #include <sys/file.h>   /* Must be after sys/types.h for USG.  */
 #include <fcntl.h>
@@ -609,7 +610,11 @@ the same file name is found in the `doc-directory'.  */)
 
   fd = emacs_open (name, O_RDONLY, 0);
   if (fd < 0)
-    report_file_error ("Opening doc string file", build_string (name));
+    {
+      int open_errno = errno;
+      report_file_errno ("Opening doc string file", build_string (name),
+                         open_errno);
+    }
   Vdoc_file_name = filename;
   filled = 0;
   pos = 0;
diff --git a/src/fileio.c b/src/fileio.c
index b74b0ca91c2..06a0db2316f 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -204,7 +204,9 @@ report_file_errno (char const *string, Lisp_Object name, int errorno)
 }
 
 /* Signal a file-access failure that set errno.  STRING describes the
-   failure, NAME the file involved.  */
+   failure, NAME the file involved.  When invoking this function, take
+   care to not use arguments such as build_string ("foo") that involve
+   side effects that may set errno.  */
 
 void
 report_file_error (char const *string, Lisp_Object name)
@@ -2371,7 +2373,8 @@ This is what happens in interactive use with M-x.  */)
                                   INTEGERP (ok_if_already_exists), 0, 0);
   if (rename (SSDATA (encoded_file), SSDATA (encoded_newname)) < 0)
     {
-      if (errno == EXDEV)
+      int rename_errno = errno;
+      if (rename_errno == EXDEV)
         {
           ptrdiff_t count;
           symlink_target = Ffile_symlink_p (file);
@@ -2397,7 +2400,7 @@ This is what happens in interactive use with M-x.  */)
           unbind_to (count, Qnil);
         }
       else
-        report_file_error ("Renaming", list2 (file, newname));
+        report_file_errno ("Renaming", list2 (file, newname), rename_errno);
     }
   UNGCPRO;
   return Qnil;
@@ -2451,7 +2454,10 @@ This is what happens in interactive use with M-x.  */)
 
   unlink (SSDATA (newname));
   if (link (SSDATA (encoded_file), SSDATA (encoded_newname)) < 0)
-    report_file_error ("Adding new name", list2 (file, newname));
+    {
+      int link_errno = errno;
+      report_file_errno ("Adding new name", list2 (file, newname), link_errno);
+    }
 
   UNGCPRO;
   return Qnil;
@@ -2510,6 +2516,7 @@ This happens for interactive use with M-x.  */)
   if (symlink (SSDATA (encoded_filename), SSDATA (encoded_linkname)) < 0)
     {
       /* If we didn't complain already, silently delete existing file.  */
+      int symlink_errno;
       if (errno == EEXIST)
         {
           unlink (SSDATA (encoded_linkname));
@@ -2527,7 +2534,9 @@ This happens for interactive use with M-x.  */)
                     build_string ("Symbolic links are not supported"));
         }
 
-      report_file_error ("Making symbolic link", list2 (filename, linkname));
+      symlink_errno = errno;
+      report_file_errno ("Making symbolic link", list2 (filename, linkname),
+                         symlink_errno);
     }
   UNGCPRO;
   return Qnil;
diff --git a/src/process.c b/src/process.c
index 42a625b7e55..7c63964aee6 100644
--- a/src/process.c
+++ b/src/process.c
@@ -2321,7 +2321,12 @@ set_socket_option (int s, Lisp_Object opt, Lisp_Object val)
     }
 
   if (ret < 0)
-    report_file_error ("Cannot set network option", list2 (opt, val));
+    {
+      int setsockopt_errno = errno;
+      report_file_errno ("Cannot set network option", list2 (opt, val),
+                         setsockopt_errno);
+    }
+
   return (1 << sopt->optbit);
 }