/contrib/cvs/lib/xgetwd.c

 1/* xgetwd.c -- return current directory with unlimited length
 2   Copyright (C) 1992, 1997 Free Software Foundation, Inc.
 3
 4   This program is free software; you can redistribute it and/or modify
 5   it under the terms of the GNU General Public License as published by
 6   the Free Software Foundation; either version 2, or (at your option)
 7   any later version.
 8
 9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.  */
13
14/* Derived from xgetcwd.c in e.g. the GNU sh-utils.  */
15
16#ifdef HAVE_CONFIG_H
17#include <config.h>
18#endif
19
20#include "system.h"
21
22#include <stdio.h>
23#include <errno.h>
24#ifndef errno
25extern int errno;
26#endif
27#include <sys/types.h>
28
29/* Amount by which to increase buffer size when allocating more space. */
30#define PATH_INCR 32
31
32char *xmalloc ();
33char *xrealloc ();
34
35/* Return the current directory, newly allocated, arbitrarily long.
36   Return NULL and set errno on error. */
37
38char *
39xgetwd ()
40{
41  char *cwd;
42  char *ret;
43  unsigned path_max;
44
45  errno = 0;
46  path_max = (unsigned) PATH_MAX;
47  path_max += 2;		/* The getcwd docs say to do this. */
48
49  cwd = xmalloc (path_max);
50
51  errno = 0;
52  while ((ret = getcwd (cwd, path_max)) == NULL && errno == ERANGE)
53    {
54      path_max += PATH_INCR;
55      cwd = xrealloc (cwd, path_max);
56      errno = 0;
57    }
58
59  if (ret == NULL)
60    {
61      int save_errno = errno;
62      free (cwd);
63      errno = save_errno;
64      return NULL;
65    }
66  return cwd;
67}