[ChangeLog]

Work around some portability problems with symlinks.
* Makefile.in (GNULIB_MODULES): Add lstat, readlink, symlink.
* configure.in (lstat, HAVE_LSTAT): Remove special hack.
* lib/lstat.c, lib/readlink.c, lib/stat.c, lib/symlink.c:
* m4/dos.m4, m4/lstat.m4, m4/readlink.m4, m4/stat.m4, m4/symlink.m4:
New files, automatically generated from gnulib.
* aclocal.m4, configure, lib/Makefile.in, lib/gnulib.mk:
* lib/stdlib.in.h, m4/gl-comp.m4, m4/stdlib_h.m4: Regenerate.

2011-02-22  Paul Eggert  <eggert@cs.ucla.edu>
[src/ChangeLog]
Work around some portability problems with symlinks.
* fileio.c (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.

1 files changed, 91 insertions, 0 deletions

diff --git a/lib/lstat.c b/lib/lstat.c
new file mode 100644
index 00000000000..b26065ede28
--- /dev/null
+++ b/lib/lstat.c
@@ -0,0 +1,91 @@
+/* Work around a bug of lstat on some systems
+
+   Copyright (C) 1997-2006, 2008-2011 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+#if !HAVE_LSTAT
+/* On systems that lack symlinks, our replacement <sys/stat.h> already
+   defined lstat as stat, so there is nothing further to do other than
+   avoid an empty file.  */
+typedef int dummy;
+#else /* HAVE_LSTAT */
+
+/* Get the original definition of lstat.  It might be defined as a macro.  */
+# define __need_system_sys_stat_h
+# include <sys/types.h>
+# include <sys/stat.h>
+# undef __need_system_sys_stat_h
+
+static inline int
+orig_lstat (const char *filename, struct stat *buf)
+{
+  return lstat (filename, buf);
+}
+
+/* Specification.  */
+# include <sys/stat.h>
+
+# include <string.h>
+# include <errno.h>
+
+/* lstat works differently on Linux and Solaris systems.  POSIX (see
+   `pathname resolution' in the glossary) requires that programs like
+   `ls' take into consideration the fact that FILE has a trailing slash
+   when FILE is a symbolic link.  On Linux and Solaris 10 systems, the
+   lstat function already has the desired semantics (in treating
+   `lstat ("symlink/", sbuf)' just like `lstat ("symlink/.", sbuf)',
+   but on Solaris 9 and earlier it does not.
+
+   If FILE has a trailing slash and specifies a symbolic link,
+   then use stat() to get more info on the referent of FILE.
+   If the referent is a non-directory, then set errno to ENOTDIR
+   and return -1.  Otherwise, return stat's result.  */
+
+int
+rpl_lstat (const char *file, struct stat *sbuf)
+{
+  size_t len;
+  int lstat_result = orig_lstat (file, sbuf);
+
+  if (lstat_result != 0)
+    return lstat_result;
+
+  /* This replacement file can blindly check against '/' rather than
+     using the ISSLASH macro, because all platforms with '\\' either
+     lack symlinks (mingw) or have working lstat (cygwin) and thus do
+     not compile this file.  0 len should have already been filtered
+     out above, with a failure return of ENOENT.  */
+  len = strlen (file);
+  if (file[len - 1] != '/' || S_ISDIR (sbuf->st_mode))
+    return 0;
+
+  /* At this point, a trailing slash is only permitted on
+     symlink-to-dir; but it should have found information on the
+     directory, not the symlink.  Call stat() to get info about the
+     link's referent.  Our replacement stat guarantees valid results,
+     even if the symlink is not pointing to a directory.  */
+  if (!S_ISLNK (sbuf->st_mode))
+    {
+      errno = ENOTDIR;
+      return -1;
+    }
+  return stat (file, sbuf);
+}
+
+#endif /* HAVE_LSTAT */