/* xgetcwd.c -- return current directory with unlimited length
- Copyright (C) 1992, 1996, 2000, 2001 Free Software Foundation, Inc.
+ Copyright (C) 1992, 1996, 2000, 2001, 2003 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
#if HAVE_GETCWD
char *getcwd ();
#else
+# include "pathmax.h"
+# define INITIAL_BUFFER_SIZE (PATH_MAX + 1)
char *getwd ();
# define getcwd(Buf, Max) getwd (Buf)
#endif
#include "xalloc.h"
+#include "xgetcwd.h"
-/* Return the current directory, newly allocated, arbitrarily long.
- Return NULL and set errno on error. */
+/* Return the current directory, newly allocated, assuming it fits
+ within PATH_MAX bytes -- this is a common system-imposed limit
+ on how getcwd works.
+ Upon an out-of-memory error, call xalloc_die.
+ Upon any other type of error, return NULL. */
char *
-xgetcwd ()
+xgetcwd (void)
{
#if HAVE_GETCWD_NULL
- return getcwd (NULL, 0);
+ char *cwd = getcwd (NULL, 0);
+ if (! cwd && errno == ENOMEM)
+ xalloc_die ();
+ return cwd;
#else
- size_t buf_size = 128; /* must be a power of 2 */
- char *buf = NULL;
+
+ /* The initial buffer size for the working directory. A power of 2
+ detects arithmetic overflow earlier, but is not required. */
+# ifndef INITIAL_BUFFER_SIZE
+# define INITIAL_BUFFER_SIZE 128
+# endif
+
+ size_t buf_size = INITIAL_BUFFER_SIZE;
while (1)
{
- char *cwd;
- buf = (char *) xrealloc (buf, buf_size);
-
- cwd = getcwd (buf, buf_size);
- if (cwd != NULL)
+ char *buf = xmalloc (buf_size);
+ char *cwd = getcwd (buf, buf_size);
+ int saved_errno;
+ if (cwd)
return cwd;
- if (errno != ERANGE)
- {
- free (buf);
- return NULL;
- }
-
+ saved_errno = errno;
+ free (buf);
+ if (saved_errno != ERANGE)
+ return NULL;
buf_size *= 2;
if (buf_size == 0)
xalloc_die ();