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Diffstat (limited to 'jni/iconv/srclib/areadlink.c')
-rw-r--r--jni/iconv/srclib/areadlink.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/jni/iconv/srclib/areadlink.c b/jni/iconv/srclib/areadlink.c
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+++ b/jni/iconv/srclib/areadlink.c
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+/* areadlink.c -- readlink wrapper to return the link name in malloc'd storage
+ Unlike xreadlink and xreadlink_with_size, don't ever call exit.
+
+ Copyright (C) 2001, 2003-2007 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 of the License, 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, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Jim Meyering <jim@meyering.net>
+ and Bruno Haible <bruno@clisp.org>. */
+
+#include <config.h>
+
+/* Specification. */
+#include "areadlink.h"
+
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#ifndef SIZE_MAX
+# define SIZE_MAX ((size_t) -1)
+#endif
+#ifndef SSIZE_MAX
+# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
+#endif
+
+/* 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 and set errno.
+ If realloc fails, or if the link value is longer than SIZE_MAX :-),
+ return NULL and set errno to ENOMEM. */
+
+char *
+areadlink (char const *filename)
+{
+ /* The initial buffer size for the link value. A power of 2
+ detects arithmetic overflow earlier, but is not required. */
+#define INITIAL_BUF_SIZE 1024
+
+ /* Allocate the initial buffer on the stack. This way, in the common
+ case of a symlink of small size, we get away with a single small malloc()
+ instead of a big malloc() followed by a shrinking realloc(). */
+ char initial_buf[INITIAL_BUF_SIZE];
+
+ char *buffer = initial_buf;
+ size_t buf_size = sizeof (initial_buf);
+
+ while (1)
+ {
+ /* Attempt to read the link into the current buffer. */
+ ssize_t link_length = readlink (filename, buffer, buf_size);
+
+ /* On AIX 5L v5.3 and HP-UX 11i v2 04/09, readlink returns -1
+ with errno == ERANGE if the buffer is too small. */
+ if (link_length < 0 && errno != ERANGE)
+ {
+ if (buffer != initial_buf)
+ {
+ int saved_errno = errno;
+ free (buffer);
+ errno = saved_errno;
+ }
+ return NULL;
+ }
+
+ if ((size_t) link_length < buf_size)
+ {
+ buffer[link_length++] = '\0';
+
+ /* Return it in a chunk of memory as small as possible. */
+ if (buffer == initial_buf)
+ {
+ buffer = (char *) malloc (link_length);
+ if (buffer == NULL)
+ /* errno is ENOMEM. */
+ return NULL;
+ memcpy (buffer, initial_buf, link_length);
+ }
+ else
+ {
+ /* Shrink buffer before returning it. */
+ if ((size_t) link_length < buf_size)
+ {
+ char *smaller_buffer = (char *) realloc (buffer, link_length);
+
+ if (smaller_buffer != NULL)
+ buffer = smaller_buffer;
+ }
+ }
+ return buffer;
+ }
+
+ if (buffer != initial_buf)
+ free (buffer);
+ buf_size *= 2;
+ if (SSIZE_MAX < buf_size || (SIZE_MAX / 2 < SSIZE_MAX && buf_size == 0))
+ {
+ errno = ENOMEM;
+ return NULL;
+ }
+ buffer = (char *) malloc (buf_size);
+ if (buffer == NULL)
+ /* errno is ENOMEM. */
+ return NULL;
+ }
+}