1 /* -*- buffer-read-only: t -*- vi: set ro: */
2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
3 /* readlink wrapper to return the link name in malloc'd storage.
4 Unlike xreadlink and xreadlink_with_size, don't ever call exit.
6 Copyright (C) 2001, 2003-2007, 2009-2010 Free Software Foundation, Inc.
8 This program is free software: you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 /* Written by Jim Meyering <jim@meyering.net> */
25 #include "areadlink.h"
34 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
37 /* SYMLINK_MAX is used only for an initial memory-allocation sanity
38 check, so it's OK to guess too small on hosts where there is no
39 arbitrary limit to symbolic link length. */
41 # define SYMLINK_MAX 1024
44 #define MAXSIZE (SIZE_MAX < SSIZE_MAX ? SIZE_MAX : SSIZE_MAX)
46 /* Call readlink to get the symbolic link value of FILE.
47 SIZE is a hint as to how long the link is expected to be;
48 typically it is taken from st_size. It need not be correct.
49 Return a pointer to that NUL-terminated string in malloc'd storage.
50 If readlink fails, malloc fails, or if the link value is longer
51 than SSIZE_MAX, return NULL (caller may use errno to diagnose). */
54 areadlink_with_size (char const *file, size_t size)
56 /* Some buggy file systems report garbage in st_size. Defend
57 against them by ignoring outlandish st_size values in the initial
59 size_t symlink_max = SYMLINK_MAX;
60 size_t INITIAL_LIMIT_BOUND = 8 * 1024;
61 size_t initial_limit = (symlink_max < INITIAL_LIMIT_BOUND
63 : INITIAL_LIMIT_BOUND);
65 /* The initial buffer size for the link value. */
66 size_t buf_size = size < initial_limit ? size + 1 : initial_limit;
72 char *buffer = malloc (buf_size);
76 r = readlink (file, buffer, buf_size);
79 /* On AIX 5L v5.3 and HP-UX 11i v2 04/09, readlink returns -1
80 with errno == ERANGE if the buffer is too small. */
81 if (r < 0 && errno != ERANGE)
83 int saved_errno = errno;
89 if (link_length < buf_size)
91 buffer[link_length] = 0;
96 if (buf_size <= MAXSIZE / 2)
98 else if (buf_size < MAXSIZE)