95 lines
2.6 KiB
C
95 lines
2.6 KiB
C
/* Determine current working directory. Linux version.
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Copyright (C) 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <unistd.h>
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/* #define NDEBUG 1 */
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#include <assert.h>
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/* The "proc" filesystem provides an easy method to retrieve the value.
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For each process, the corresponding directory contains a symbolic link
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named `cwd'. Reading the content of this link immediate gives us the
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information. But we have to take care for systems which do not have
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the proc filesystem mounted. Use the POSIX implementation in this case. */
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static char *generic_getcwd (char *buf, size_t size);
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char *
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__getcwd (char *buf, size_t size)
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{
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int save_errno;
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char *path;
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int n;
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char *result;
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if (size == 0)
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{
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if (buf != NULL)
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{
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__set_errno (EINVAL);
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return NULL;
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}
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size = PATH_MAX + 1;
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}
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if (buf != NULL)
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path = buf;
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else
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{
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path = malloc (size);
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if (path == NULL)
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return NULL;
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}
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save_errno = errno;
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n = __readlink ("/proc/self/cwd", path, size);
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if (n != -1)
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{
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if (n >= size)
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{
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/* This should never happen when we allocate the buffer here. */
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assert (buf == NULL);
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__set_errno (ERANGE);
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return NULL;
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}
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path[n] = '\0';
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return buf ?: (char *) realloc (path, (size_t) n + 1);
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}
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/* Something went wrong. Restore the error number and use the generic
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version. */
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__set_errno (save_errno);
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result = generic_getcwd (path, size);
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if (result == NULL && buf == NULL)
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free (path);
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return result;
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}
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weak_alias (__getcwd, getcwd)
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/* Get the code for the generic version. */
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#define GETCWD_STORAGE_CLASS static
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#define __getcwd generic_getcwd
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#include <sysdeps/posix/getcwd.c>
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