gnulib module 'xreadlink'.

diff --git a/gettext-tools/lib/xreadlink.c b/gettext-tools/lib/xreadlink.c
new file mode 100644 (file)
index 0000000..0322ca7
--- /dev/null
+++ b/gettext-tools/lib/xreadlink.c
@@ -0,0 +1,143 @@
+/* xreadlink.c -- readlink wrapper to return the link name in malloc'd storage
+
+   Copyright 2001, 2003 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 2, 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; see the file COPYING.
+   If not, write to the Free Software Foundation,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* Written by Jim Meyering <jim@meyering.net>
+   and Bruno Haible <bruno@clisp.org>.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification.  */
+#include "xreadlink.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#ifndef errno
+extern int errno;
+#endif
+
+#if HAVE_LIMITS_H
+# include <limits.h>
+#endif
+#if HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#if HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#ifndef SIZE_MAX
+# define SIZE_MAX ((size_t) -1)
+#endif
+#ifndef SSIZE_MAX
+# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
+#endif
+
+#ifdef NO_XMALLOC
+# define xmalloc malloc
+#else
+# include "xmalloc.h"
+#endif
+
+/* Call readlink to get the symbolic link value of FILENAME.
+   Return a pointer to that NUL-terminated string in malloc'd storage.
+   If readlink fails, return NULL (caller may use errno to diagnose).
+   If realloc fails, or if the link value is longer than SIZE_MAX :-),
+   give a diagnostic and exit.  */
+
+char *
+xreadlink (char const *filename)
+{
+  /* The initial buffer size for the link value.  A power of 2
+     detects arithmetic overflow earlier, but is not required.  */
+#define INITIAL_BUF_SIZE 1024
+
+  /* Allocate the initial buffer on the stack.  This way, in the common
+     case of a symlink of small size, we get away with a single small malloc()
+     instead of a big malloc() followed by a shrinking realloc().  */
+  char initial_buf[INITIAL_BUF_SIZE];
+
+  char *buffer = initial_buf;
+  size_t buf_size = sizeof (initial_buf);
+
+  while (1)
+    {
+      /* Attempt to read the link into the current buffer.  */
+      ssize_t link_length = readlink (filename, buffer, buf_size);
+
+      if (link_length < 0)
+       {
+         if (buffer != initial_buf)
+           {
+             int saved_errno = errno;
+             free (buffer);
+             errno = saved_errno;
+           }
+         return NULL;
+       }
+
+      if ((size_t) link_length < buf_size)
+       {
+         buffer[link_length++] = '\0';
+
+         /* Return it in a chunk of memory as small as possible.  */
+         if (buffer == initial_buf)
+           {
+             buffer = (char *) xmalloc (link_length);
+#ifdef NO_XMALLOC
+             if (buffer == NULL)
+               return NULL;
+#endif
+             memcpy (buffer, initial_buf, link_length);
+           }
+         else
+           {
+             /* Shrink buffer before returning it.  */
+             if ((size_t) link_length < buf_size)
+               {
+                 char *smaller_buffer = (char *) realloc (buffer, link_length);
+
+                 if (smaller_buffer != NULL)
+                   buffer = smaller_buffer;
+               }
+           }
+         return buffer;
+       }
+
+      if (buffer != initial_buf)
+       free (buffer);
+      buf_size *= 2;
+      if (SSIZE_MAX < buf_size || (SIZE_MAX / 2 < SSIZE_MAX && buf_size == 0))
+#ifdef NO_XMALLOC
+       return NULL;
+#else
+       xalloc_die ();
+#endif
+      buffer = (char *) xmalloc (buf_size);
+#ifdef NO_XMALLOC
+      if (buffer == NULL)
+       return NULL;
+#endif
+    }
+}

diff --git a/gettext-tools/lib/xreadlink.h b/gettext-tools/lib/xreadlink.h
new file mode 100644 (file)
index 0000000..2b35106
--- /dev/null
+++ b/gettext-tools/lib/xreadlink.h
@@ -0,0 +1,21 @@
+/* Reading symbolic links without size limitation.
+   Copyright (C) 2001, 2003 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 2, 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, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* Call readlink to get the symbolic link value of FILENAME.
+   Return a pointer to that NUL-terminated string in malloc'd storage.
+   If readlink fails, return NULL and set errno.  */
+extern char *xreadlink (char const *filename);

diff --git a/gettext-tools/m4/xreadlink.m4 b/gettext-tools/m4/xreadlink.m4
new file mode 100644 (file)
index 0000000..cc9eeb4
--- /dev/null
+++ b/gettext-tools/m4/xreadlink.m4
@@ -0,0 +1,13 @@
+# xreadlink.m4 serial 1 (gettext-0.12)
+dnl Copyright (C) 2002 Free Software Foundation, Inc.
+dnl This file is free software, distributed under the terms of the GNU
+dnl General Public License.  As a special exception to the GNU General
+dnl Public License, this file may be distributed as part of a program
+dnl that contains a configuration script generated by Autoconf, under
+dnl the same distribution terms as the rest of that program.
+
+AC_DEFUN([gl_XREADLINK],
+[
+  dnl Prerequisites of lib/xreadlink.c.
+  AC_CHECK_HEADERS_ONCE(limits.h stdlib.h sys/types.h unistd.h)
+])