X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fxgetcwd.c;h=785002e0ec5c964388aac6ffe74ac5f63709cee4;hb=5b3ef25d51691462730b000864e0eb09ebd34013;hp=55e12afcd1d79d7d5854aa0e8e4f3ccadf13a38e;hpb=904dc8bf73cb93f620eb1d159c2124f801d790fd;p=gnulib.git

diff --git a/lib/xgetcwd.c b/lib/xgetcwd.c
index 55e12afcd..785002e0e 100644
--- a/lib/xgetcwd.c
+++ b/lib/xgetcwd.c
@@ -1,5 +1,7 @@
 /* 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, 2004 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
@@ -23,15 +25,9 @@
 
 #include <stdio.h>
 #include <errno.h>
-#ifndef errno
-extern int errno;
-#endif
-
 #include <sys/types.h>
+#include <stdlib.h>
 
-#if HAVE_STDLIB_H
-# include <stdlib.h>
-#endif
 #if HAVE_UNISTD_H
 # include <unistd.h>
 #endif
@@ -39,38 +35,50 @@ extern int errno;
 #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 defined __GLIBC__ && __GLIBC__ >= 2
-  return getcwd (NULL, 0);
+#if HAVE_GETCWD_NULL
+  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 *ret;
-      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 ();