/* areadlink.c -- readlink wrapper to return the link name in malloc'd storage
Unlike xreadlink and xreadlink_with_size, don't ever call exit.
- 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
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>. */
/* Specification. */
#include "areadlink.h"
-#include <string.h>
#include <errno.h>
#include <limits.h>
-#include <sys/types.h>
+#include <stdint.h>
#include <stdlib.h>
+#include <string.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
+/* Use the system functions, not the gnulib overrides in this file. */
+#undef malloc
+#undef realloc
+
+/* The initial buffer size for the link value. A power of 2
+ detects arithmetic overflow earlier, but is not required. */
+enum {
+ INITIAL_BUF_SIZE = 1024
+};
+
/* 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.
char *
areadlink (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);
+ size_t buf_size = sizeof initial_buf;
while (1)
{
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. */
+ 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 (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 *) malloc (link_length);
- if (buffer == NULL)
- /* errno is ENOMEM. */
- return NULL;
- 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;
- }
+ {
+ buffer[link_length++] = '\0';
+
+ /* Return it in a chunk of memory as small as possible. */
+ if (buffer == initial_buf)
+ {
+ buffer = (char *) malloc (link_length);
+ if (buffer == NULL)
+ {
+ /* It's easier to set errno to ENOMEM than to rely on the
+ 'malloc-posix' gnulib module. */
+ errno = ENOMEM;
+ return NULL;
+ }
+ 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);
+ free (buffer);
buf_size *= 2;
if (SSIZE_MAX < buf_size || (SIZE_MAX / 2 < SSIZE_MAX && buf_size == 0))
- {
- errno = ENOMEM;
- return NULL;
- }
+ {
+ errno = ENOMEM;
+ return NULL;
+ }
buffer = (char *) malloc (buf_size);
if (buffer == NULL)
- /* errno is ENOMEM. */
- return NULL;
+ {
+ /* It's easier to set errno to ENOMEM than to rely on the
+ 'malloc-posix' gnulib module. */
+ errno = ENOMEM;
+ return NULL;
+ }
}
}
projects / gnulib.git / blobdiff