[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, 62 insertions, 0 deletions

diff --git a/m4/readlink.m4 b/m4/readlink.m4
new file mode 100644
index 00000000000..a502ca560fe
--- /dev/null
+++ b/m4/readlink.m4
@@ -0,0 +1,62 @@
+# readlink.m4 serial 9
+dnl Copyright (C) 2003, 2007, 2009-2011 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_READLINK],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([readlink])
+  if test $ac_cv_func_readlink = no; then
+    HAVE_READLINK=0
+    AC_LIBOBJ([readlink])
+    gl_PREREQ_READLINK
+  else
+    AC_CACHE_CHECK([whether readlink signature is correct],
+      [gl_cv_decl_readlink_works],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+      /* Cause compilation failure if original declaration has wrong type.  */
+      ssize_t readlink (const char *, char *, size_t);]])],
+         [gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
+    dnl Solaris 9 ignores trailing slash.
+    dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
+    AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
+      [gl_cv_func_readlink_works],
+      [# We have readlink, so assume ln -s works.
+       ln -s conftest.no-such conftest.link
+       ln -s conftest.link conftest.lnk2
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+]], [[char buf[20];
+      return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
+         [gl_cv_func_readlink_works=yes], [gl_cv_func_readlink_works=no],
+         [gl_cv_func_readlink_works="guessing no"])
+      rm -f conftest.link conftest.lnk2])
+    if test "$gl_cv_func_readlink_works" != yes; then
+      AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
+        fails to recognize a trailing slash.])
+      REPLACE_READLINK=1
+      AC_LIBOBJ([readlink])
+    elif test "$gl_cv_decl_readlink_works" != yes; then
+      REPLACE_READLINK=1
+      AC_LIBOBJ([readlink])
+    fi
+  fi
+])
+
+# Like gl_FUNC_READLINK, except prepare for separate compilation (no AC_LIBOBJ).
+AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
+[
+  AC_CHECK_FUNCS_ONCE([readlink])
+  gl_PREREQ_READLINK
+])
+
+# Prerequisites of lib/readlink.c.
+AC_DEFUN([gl_PREREQ_READLINK],
+[
+  :
+])