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authorJim Meyering <jim@meyering.net>2001-09-01 09:50:48 +0000
committerJim Meyering <jim@meyering.net>2001-09-01 09:50:48 +0000
commit31555f918ccf427eb98b0d61c3a0f3c5505184b3 (patch)
treeb8c25804599d1b599f0994299fc6495255c77797 /lib/xreadlink.c
parent1d9ccbf010e8374473f9fdd72f4d5c51206d6bc5 (diff)
downloadcoreutils-31555f918ccf427eb98b0d61c3a0f3c5505184b3.tar.xz
*** empty log message ***
Diffstat (limited to 'lib/xreadlink.c')
-rw-r--r--lib/xreadlink.c72
1 files changed, 72 insertions, 0 deletions
diff --git a/lib/xreadlink.c b/lib/xreadlink.c
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--- /dev/null
+++ b/lib/xreadlink.c
@@ -0,0 +1,72 @@
+/* exclude.c -- exclude file names
+
+ Copyright 2001 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 2, 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; see the file COPYING.
+ If not, write to the Free Software Foundation,
+ 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/* Written by Jim Meyering <jim@meyering.net> */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdio.h>
+#if HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#if HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#include "xalloc.h"
+#include "xreadlink.h"
+
+/* Call readlink to get the symbolic link value of FILENAME.
+ Return a pointer to that NUL-terminated string in malloc'd storage.
+ If readlink fails, return NULL (use errno to diagnose).
+ If realloc fails, or if the link value is longer than SIZE_MAX :-),
+ give a diagnostic and exit. */
+
+char *
+xreadlink (char const *filename, size_t *link_length_arg)
+{
+ size_t buf_size = 128; /* must be a power of 2 */
+ char *buffer = NULL;
+
+ while (1)
+ {
+ int link_length;
+ buffer = (char *) xrealloc (buffer, buf_size);
+ link_length = readlink (filename, buffer, buf_size);
+ if (link_length < 0)
+ {
+ free (buffer);
+ return NULL;
+ }
+ if (link_length < buf_size)
+ {
+ *link_length_arg = link_length;
+ buffer[link_length] = 0;
+ return buffer;
+ }
+ buf_size *= 2;
+ if (buf_size == 0)
+ xalloc_die ();
+ }
+}