Fix openp errno handling.

* callproc.c (Fcall_process): Preserve openp errno around close.
* lread.c (openp): Set errno when returning -1, as some callers
expect this.

3 files changed, 51 insertions, 15 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index b95488c1e70..f8221e2fd36 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2013-07-07  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Fix openp errno handling.
+        * callproc.c (Fcall_process): Preserve openp errno around close.
+        * lread.c (openp): Set errno when returning -1, as some callers
+        expect this.
+
 2013-07-06  Jan Djärv  <jan.h.d@swipnet.se>
 
         * nsterm.m (sendEvent:): Handle NSAPP_DATA2_RUNFILEDIALOG.
diff --git a/src/callproc.c b/src/callproc.c
index 6de8113dc14..185dc9a493e 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -436,7 +436,9 @@ usage: (call-process PROGRAM &optional INFILE DESTINATION DISPLAY &rest ARGS)  *
   }
   if (NILP (path))
     {
+      int openp_errno = errno;
       emacs_close (filefd);
+      errno = openp_errno;
       report_file_error ("Searching for program", Fcons (args[0], Qnil));
     }
 
diff --git a/src/lread.c b/src/lread.c
index 06badce12be..2ceeb106653 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -1448,14 +1448,15 @@ static Lisp_Object Qdir_ok;
 
 /* Search for a file whose name is STR, looking in directories
    in the Lisp list PATH, and trying suffixes from SUFFIX.
-   On success, returns a file descriptor.  On failure, returns -1.
+   On success, return a file descriptor (or 1 or -2 as described below).
+   On failure, return -1 and set errno.
 
    SUFFIXES is a list of strings containing possible suffixes.
    The empty suffix is automatically added if the list is empty.
 
    PREDICATE non-nil means don't open the files,
    just look for one that satisfies the predicate.  In this case,
-   returns 1 on success.  The predicate can be a lisp function or
+   return 1 on success.  The predicate can be a lisp function or
    an integer to pass to `access' (in which case file-name-handlers
    are ignored).
 
@@ -1467,7 +1468,8 @@ static Lisp_Object Qdir_ok;
    but store the found remote file name in *STOREPTR.  */
 
 int
-openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, Lisp_Object *storeptr, Lisp_Object predicate)
+openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes,
+       Lisp_Object *storeptr, Lisp_Object predicate)
 {
   ptrdiff_t fn_size = 100;
   char buf[100];
@@ -1478,6 +1480,7 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, Lisp_Object *sto
   struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5, gcpro6;
   Lisp_Object string, tail, encoded_fn;
   ptrdiff_t max_suffix_len = 0;
+  int last_errno = ENOENT;
 
   CHECK_STRING (str);
 
@@ -1547,14 +1550,22 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, Lisp_Object *sto
           if ((!NILP (handler) || !NILP (predicate)) && !NATNUMP (predicate))
             {
               bool exists;
+              last_errno = ENOENT;
               if (NILP (predicate))
                 exists = !NILP (Ffile_readable_p (string));
               else
                 {
                   Lisp_Object tmp = call1 (predicate, string);
-                  exists = !NILP (tmp)
-                    && (EQ (tmp, Qdir_ok)
-                        || NILP (Ffile_directory_p (string)));
+                  if (NILP (tmp))
+                    exists = 0;
+                  else if (EQ (tmp, Qdir_ok)
+                           || NILP (Ffile_directory_p (string)))
+                    exists = 1;
+                  else
+                    {
+                      exists = 0;
+                      last_errno = EISDIR;
+                    }
                 }
 
               if (exists)
@@ -1576,21 +1587,36 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, Lisp_Object *sto
 
               /* Check that we can access or open it.  */
               if (NATNUMP (predicate))
-                fd = (((XFASTINT (predicate) & ~INT_MAX) == 0
-                       && (faccessat (AT_FDCWD, pfn, XFASTINT (predicate),
+                {
+                  fd = -1;
+                  if (INT_MAX < XFASTINT (predicate))
+                    last_errno = EINVAL;
+                  else if (faccessat (AT_FDCWD, pfn, XFASTINT (predicate),
                                       AT_EACCESS)
                            == 0)
-                       && ! file_directory_p (pfn))
-                      ? 1 : -1);
+                    {
+                      if (file_directory_p (pfn))
+                        last_errno = EISDIR;
+                      else
+                        fd = 1;
+                    }
+                }
               else
                 {
-                  struct stat st;
                   fd = emacs_open (pfn, O_RDONLY, 0);
-                  if (fd >= 0
-                      && (fstat (fd, &st) != 0 || S_ISDIR (st.st_mode)))
+                  if (fd < 0)
+                    last_errno = errno;
+                  else
                     {
-                      emacs_close (fd);
-                      fd = -1;
+                      struct stat st;
+                      int err = (fstat (fd, &st) != 0 ? errno
+                                 : S_ISDIR (st.st_mode) ? EISDIR : 0);
+                      if (err)
+                        {
+                          last_errno = err;
+                          emacs_close (fd);
+                          fd = -1;
+                        }
                     }
                 }
 
@@ -1609,6 +1635,7 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, Lisp_Object *sto
     }
 
   UNGCPRO;
+  errno = last_errno;
   return -1;
 }