diff options
Diffstat (limited to 'extension/xreadlink.c')
-rw-r--r-- | extension/xreadlink.c | 95 |
1 files changed, 0 insertions, 95 deletions
diff --git a/extension/xreadlink.c b/extension/xreadlink.c deleted file mode 100644 index 91e46d9d..00000000 --- a/extension/xreadlink.c +++ /dev/null @@ -1,95 +0,0 @@ -/* xreadlink.c -- readlink wrapper to return the link name in malloc'd storage - - Copyright (C) 2001, 2003, 2004, 2005, 2011 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, - 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ - -/* Written by Jim Meyering <jim@meyering.net> */ - -#if HAVE_CONFIG_H -# include <config.h> -#endif - -#include "xreadlink.h" - -#include <stdio.h> -#include <errno.h> -#include <limits.h> -#include <sys/types.h> -#include <stdlib.h> -#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 - -#define MAXSIZE (SIZE_MAX < SSIZE_MAX ? SIZE_MAX : SSIZE_MAX) - -#include "xalloc.h" - -int plugin_is_GPL_compatible; - -/* Call readlink to get the symbolic link value of FILE. - SIZE is a hint as to how long the link is expected to be; - typically it is taken from st_size. It need not be correct. - Return a pointer to that NUL-terminated string in malloc'd storage. - If readlink fails, return NULL (caller may use errno to diagnose). - If malloc fails, or if the link value is longer than SSIZE_MAX :-), - give a diagnostic and exit. */ - -char * -xreadlink (char const *file, size_t size) -{ - /* The initial buffer size for the link value. A power of 2 - detects arithmetic overflow earlier, but is not required. */ - size_t buf_size = size < MAXSIZE ? size + 1 : MAXSIZE; - - while (1) - { - char *buffer = xmalloc (buf_size); - ssize_t r = readlink (file, buffer, buf_size); - size_t link_length = r; - - /* 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 (r < 0 && errno != ERANGE) - { - int saved_errno = errno; - free (buffer); - errno = saved_errno; - return NULL; - } - - if (link_length < buf_size) - { - buffer[link_length] = 0; - return buffer; - } - - free (buffer); - if (buf_size <= MAXSIZE / 2) - buf_size *= 2; - else if (buf_size < MAXSIZE) - buf_size = MAXSIZE; - else - xalloc_die (); - } -} |