Imported Upstream version 8.24upstream/8.24upstream

1 files changed, 44 insertions, 12 deletions

diff --git a/lib/readlinkat.c b/lib/readlinkat.c
index c8a60500..c91cf0e8 100644
--- a/lib/readlinkat.c
+++ b/lib/readlinkat.c
@@ -1,5 +1,5 @@
 /* Read a symlink relative to an open directory.
-   Copyright (C) 2009-2014 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015 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
@@ -18,7 +18,37 @@
 
 #include <config.h>
 
+#include <errno.h>
 #include <unistd.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#if HAVE_READLINKAT
+
+# undef readlinkat
+
+ssize_t
+rpl_readlinkat (int fd, char const *file, char *buf, size_t len)
+{
+# if READLINK_TRAILING_SLASH_BUG
+  size_t file_len = strlen (file);
+  if (file_len && file[file_len - 1] == '/')
+    {
+      /* Even if FILE without the slash is a symlink to a directory,
+         both lstat() and stat() must resolve the trailing slash to
+         the directory rather than the symlink.  We can therefore
+         safely use stat() to distinguish between EINVAL and
+         ENOTDIR/ENOENT, avoiding extra overhead of rpl_lstat().  */
+      struct stat st;
+      if (stat (file, &st) == 0)
+        errno = EINVAL;
+      return -1;
+    }
+# endif /* READLINK_TRAILING_SLASH_BUG */
+  return readlinkat (fd, file, buf, len);
+}
+
+#else
 
 /* Gnulib provides a readlink stub for mingw; use it for distinction
    between EINVAL and ENOENT, rather than always failing with ENOSYS.  */
@@ -34,14 +64,16 @@
    then readlink/restore_cwd.  If either the save_cwd or the restore_cwd
    fails, then give a diagnostic and exit nonzero.  */
 
-#define AT_FUNC_NAME readlinkat
-#define AT_FUNC_F1 readlink
-#define AT_FUNC_POST_FILE_PARAM_DECLS , char *buf, size_t len
-#define AT_FUNC_POST_FILE_ARGS        , buf, len
-#define AT_FUNC_RESULT ssize_t
-#include "at-func.c"
-#undef AT_FUNC_NAME
-#undef AT_FUNC_F1
-#undef AT_FUNC_POST_FILE_PARAM_DECLS
-#undef AT_FUNC_POST_FILE_ARGS
-#undef AT_FUNC_RESULT
+# define AT_FUNC_NAME readlinkat
+# define AT_FUNC_F1 readlink
+# define AT_FUNC_POST_FILE_PARAM_DECLS , char *buf, size_t len
+# define AT_FUNC_POST_FILE_ARGS        , buf, len
+# define AT_FUNC_RESULT ssize_t
+# include "at-func.c"
+# undef AT_FUNC_NAME
+# undef AT_FUNC_F1
+# undef AT_FUNC_POST_FILE_PARAM_DECLS
+# undef AT_FUNC_POST_FILE_ARGS
+# undef AT_FUNC_RESULT
+
+#endif