X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fxreadlink.c;h=4fdcafb56cb17a9eda78d6380aac8bfc4dd21368;hb=e240ab433593692f27c804c26ec1730a0dd27e5d;hp=2aba2654780912fa86c299fdff4b20a554a05385;hpb=535388620f626539486ff29e158fbecdd7e401df;p=gnulib.git

diff --git a/lib/xreadlink.c b/lib/xreadlink.c
index 2aba26547..4fdcafb56 100644
--- a/lib/xreadlink.c
+++ b/lib/xreadlink.c
@@ -1,11 +1,11 @@
 /* xreadlink.c -- readlink wrapper to return the link name in malloc'd storage
 
-   Copyright (C) 2001, 2003-2007 Free Software Foundation, Inc.
+   Copyright (C) 2001, 2003-2007, 2009-2010 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   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.
+   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
@@ -13,9 +13,7 @@
    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,
-   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* Written by Jim Meyering <jim@meyering.net>
    and Bruno Haible <bruno@clisp.org>.  */
@@ -25,107 +23,22 @@
 /* Specification.  */
 #include "xreadlink.h"
 
-#include <stdio.h>
-#include <string.h>
 #include <errno.h>
-#include <limits.h>
-#include <sys/types.h>
-#include <stdlib.h>
-#include <unistd.h>
 
-#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 "xalloc.h"
-#endif
+#include "areadlink.h"
+#include "xalloc.h"
 
 /* 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 readlink fails, return NULL and set errno.
    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);
-
-      /* On AIX 5L v5.3 and HP-UX 11i v2 04/09, readlink returns -1
-	 with errno == ERANGE if the buffer is too small.  */
-      if (link_length < 0 && errno != ERANGE)
-	{
-	  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
-    }
+  char *result = areadlink (filename);
+  if (result == NULL && errno == ENOMEM)
+    xalloc_die ();
+  return result;
 }