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75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/* Provide a replacement for the POSIX getcwd function.
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Copyright (C) 2003 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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/* written by Jim Meyering */
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#include <config.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#ifndef errno
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extern int errno;
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#endif
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#include <sys/types.h>
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#include "pathmax.h"
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#include "same.h"
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/* Guess high, because that makes the test below more conservative.
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But this is a kludge, because we should really use
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pathconf (".", _PC_NAME_MAX). But it's probably not worth the cost. */
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#define KLUDGE_POSIX_NAME_MAX 255
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#define MAX_SAFE_LEN (PATH_MAX - 1 - KLUDGE_POSIX_NAME_MAX - 1)
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/* Undefine getcwd here, as near the use as possible, in case any
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of the files included above define it to rpl_getcwd. */
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#undef getcwd
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/* Any declaration of getcwd from headers included above has
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been changed to a declaration of rpl_getcwd. Declare it here. */
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extern char *getcwd (char *buf, size_t size);
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/* This is a wrapper for getcwd.
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Some implementations (at least GNU libc 2.3.1 + linux-2.4.20) return
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non-NULL for a working directory name longer than PATH_MAX, yet the
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returned string is a strict prefix of the desired directory name.
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Upon such a failure, free the offending string, set errno to
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ENAMETOOLONG, and return NULL.
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I've heard that this is a Linux kernel bug, and that it has
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been fixed between 2.4.21-pre3 and 2.4.21-pre4. */
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char *
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rpl_getcwd (char *buf, size_t size)
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{
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char *cwd = getcwd (buf, size);
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if (cwd == NULL)
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return NULL;
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if (strlen (cwd) <= MAX_SAFE_LEN || same_name (cwd, "."))
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return cwd;
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free (cwd);
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errno = ENAMETOOLONG;
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return NULL;
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}
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