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/* xgetcwd.c: a from-scratch version of getwd. Based on the tcsh 5.20
source, apparently uncopyrighted.
Copyright (C) 1992, 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 3, 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; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "config.h"
#include "c-pathmx.h"
#include "dirio.h"
#include "xstat.h"
/* Return the pathname of the current directory, or give a fatal error. */
string
xgetcwd ()
{
/* If the system provides getwd, use it. But don't use getcwd;
forking a process is even more expensive than all the stat calls we
make figuring out the cwd. */
#ifdef GETWD_MISSING /* whole function */
struct stat root_stat, cwd_stat;
string cwd_path = xmalloc (1);
*cwd_path = 0;
/* Find the inodes of the root and current directories. */
root_stat = xstat ("/");
cwd_stat = xstat (".");
/* Go up the directory hierarchy until we get to root, prepending each
directory we pass through to `cwd_path'. */
while (!SAME_FILE_P (root_stat, cwd_stat))
{
struct dirent *e;
DIR *parent_dir;
boolean found = false;
xchdir ("..");
parent_dir = xopendir (".");
/* Look through the parent directory for the entry with the same
inode, so we can get its name. */
while ((e = readdir (parent_dir)) != NULL && !found)
{
struct stat test_stat = xlstat (e->d_name);
if (SAME_FILE_P (test_stat, cwd_stat))
{
/* We've found it. Prepend the pathname. */
string temp = cwd_path;
cwd_path = concat3 ("/", e->d_name, cwd_path);
free (temp);
/* Set up to test the next parent. */
cwd_stat = xstat (".");
/* Stop reading this directory. */
found = true;
}
}
if (!found)
FATAL2 ("No inode %d/device %d in parent directory",
cwd_stat.st_ino, cwd_stat.st_dev);
xclosedir (parent_dir);
}
/* If the current directory is the root, cwd_path will be the empty
string, and we will have not gone through the loop. */
if (*cwd_path == 0)
cwd_path = "/";
else
/* Go back to where we were. */
xchdir (cwd_path);
return cwd_path;
#else /* not GETWD_MISSING */
string path = xmalloc (PATH_MAX + 1);
if (getwd (path) == 0)
{
fprintf (stderr, "getwd: %s", path);
exit (1);
}
return path;
#endif /* not GETWD_MISSING */
}
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