Merge: Work around some portability problems with symlinks.

3 files changed, 47 insertions, 28 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 0e5e295a622..34e28866144 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,16 @@
+2011-03-02  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Work around some portability problems with symlinks.
+
+        * fileio.c (Fmake_symbolic_link): Treat ENOSYS specially, and
+        generate a special message for it.  Suggested by Eli Zaretskii in
+        <http://lists.gnu.org/archive/html/emacs-devel/2011-02/msg00995.html>.
+        (Frename_file, Fmake_symbolic_link, Ffile_symlink_p):
+        Simplify the code by assuming that the readlink and symlink calls
+        exist, even if they always fail on this host.
+        (Ffile_readable_p): Likewise, for fifos.
+        * config.in: Regenerate.
+
 2011-02-27  Chong Yidong  <cyd@stupidchicken.com>
 
         * frame.c (store_frame_param): Don't store value directly in
diff --git a/src/config.in b/src/config.in
index ded8c6b292a..4e49b4df170 100644
--- a/src/config.in
+++ b/src/config.in
@@ -576,6 +576,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* Define to 1 if you have the `random' function. */
 #undef HAVE_RANDOM
 
+/* Define to 1 if you have the `readlink' function. */
+#undef HAVE_READLINK
+
 /* Define to 1 if you have the `recvfrom' function. */
 #undef HAVE_RECVFROM
 
@@ -696,6 +699,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* Define if struct stat has an st_dm_mode member. */
 #undef HAVE_ST_DM_MODE
 
+/* Define to 1 if you have the `symlink' function. */
+#undef HAVE_SYMLINK
+
 /* Define to 1 if you have the `sync' function. */
 #undef HAVE_SYNC
 
@@ -897,6 +903,10 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* Define to 1 if localtime caches TZ. */
 #undef LOCALTIME_CACHE
 
+/* Define to 1 if `lstat' dereferences a symlink specified with a trailing
+   slash. */
+#undef LSTAT_FOLLOWS_SLASHED_SYMLINK
+
 /* String giving fallback POP mail host. */
 #undef MAILHOST
 
@@ -968,10 +978,21 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    'ptrdiff_t'. */
 #undef PTRDIFF_T_SUFFIX
 
+/* Define to 1 if readlink fails to recognize a trailing slash. */
+#undef READLINK_TRAILING_SLASH_BUG
+
 /* Define REL_ALLOC if you want to use the relocating allocator for buffer
    space. */
 #undef REL_ALLOC
 
+/* Define to 1 if stat needs help when passed a directory name with a trailing
+   slash */
+#undef REPLACE_FUNC_STAT_DIR
+
+/* Define to 1 if stat needs help when passed a file name with a trailing
+   slash */
+#undef REPLACE_FUNC_STAT_FILE
+
 /* Define as the return type of signal handlers (`int' or `void'). */
 #undef RETSIGTYPE
 
diff --git a/src/fileio.c b/src/fileio.c
index 0225e0bf3a9..18e9dbe9680 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2178,14 +2178,11 @@ This is what happens in interactive use with M-x.  */)
       if (errno == EXDEV)
         {
           int count;
-#ifdef S_IFLNK
           symlink_target = Ffile_symlink_p (file);
           if (! NILP (symlink_target))
             Fmake_symbolic_link (symlink_target, newname,
                                  NILP (ok_if_already_exists) ? Qnil : Qt);
-          else
-#endif
-          if (!NILP (Ffile_directory_p (file)))
+          else if (!NILP (Ffile_directory_p (file)))
             call4 (Qcopy_directory, file, newname, Qt, Qnil);
           else
             /* We have already prompted if it was an integer, so don't
@@ -2197,11 +2194,7 @@ This is what happens in interactive use with M-x.  */)
           count = SPECPDL_INDEX ();
           specbind (Qdelete_by_moving_to_trash, Qnil);
 
-          if (!NILP (Ffile_directory_p (file))
-#ifdef S_IFLNK
-              && NILP (symlink_target)
-#endif
-              )
+          if (!NILP (Ffile_directory_p (file)) && NILP (symlink_target))
             call2 (Qdelete_directory, file, Qt);
           else
             Fdelete_file (file, Qnil);
@@ -2311,7 +2304,6 @@ This happens for interactive use with M-x.  */)
     RETURN_UNGCPRO (call4 (handler, Qmake_symbolic_link, filename,
                            linkname, ok_if_already_exists));
 
-#ifdef S_IFLNK
   encoded_filename = ENCODE_FILE (filename);
   encoded_linkname = ENCODE_FILE (linkname);
 
@@ -2333,17 +2325,17 @@ This happens for interactive use with M-x.  */)
               return Qnil;
             }
         }
+      if (errno == ENOSYS)
+        {
+          UNGCPRO;
+          xsignal1 (Qfile_error,
+                    build_string ("Symbolic links are not supported"));
+        }
 
       report_file_error ("Making symbolic link", list2 (filename, linkname));
     }
   UNGCPRO;
   return Qnil;
-
-#else
-  UNGCPRO;
-  xsignal1 (Qfile_error, build_string ("Symbolic links are not supported"));
-
-#endif /* S_IFLNK */
 }
 
 
@@ -2482,7 +2474,7 @@ See also `file-exists-p' and `file-attributes'.  */)
   return Qnil;
 #else /* not DOS_NT and not macintosh */
   flags = O_RDONLY;
-#if defined (S_IFIFO) && defined (O_NONBLOCK)
+#ifdef O_NONBLOCK
   /* Opening a fifo without O_NONBLOCK can wait.
      We don't want to wait.  But we don't want to mess wth O_NONBLOCK
      except in the case of a fifo, on a system which handles it.  */
@@ -2584,6 +2576,10 @@ points to a nonexistent file.  */)
   (Lisp_Object filename)
 {
   Lisp_Object handler;
+  char *buf;
+  int bufsize;
+  int valsize;
+  Lisp_Object val;
 
   CHECK_STRING (filename);
   filename = Fexpand_file_name (filename, Qnil);
@@ -2594,13 +2590,6 @@ points to a nonexistent file.  */)
   if (!NILP (handler))
     return call2 (handler, Qfile_symlink_p, filename);
 
-#ifdef S_IFLNK
-  {
-  char *buf;
-  int bufsize;
-  int valsize;
-  Lisp_Object val;
-
   filename = ENCODE_FILE (filename);
 
   bufsize = 50;
@@ -2635,10 +2624,6 @@ points to a nonexistent file.  */)
   xfree (buf);
   val = DECODE_FILE (val);
   return val;
-  }
-#else /* not S_IFLNK */
-  return Qnil;
-#endif /* not S_IFLNK */
 }
 
 DEFUN ("file-directory-p", Ffile_directory_p, Sfile_directory_p, 1, 1, 0,