1/* vi: set sw=4 ts=4: */
2/*
3 *  xreadlink.c - safe implementation of readlink.
4 *  Returns a NULL on failure...
5 */
6
7#include "libbb.h"
8
9/*
10 * NOTE: This function returns a malloced char* that you will have to free
11 * yourself. You have been warned.
12 */
13char *xmalloc_readlink(const char *path)
14{
15	enum { GROWBY = 80 }; /* how large we will grow strings by */
16
17	char *buf = NULL;
18	int bufsize = 0, readsize = 0;
19
20	do {
21		buf = xrealloc(buf, bufsize += GROWBY);
22		readsize = readlink(path, buf, bufsize);
23		if (readsize == -1) {
24			free(buf);
25			return NULL;
26		}
27	} while (bufsize < readsize + 1);
28
29	buf[readsize] = '\0';
30
31	return buf;
32}
33
34char *xmalloc_readlink_or_warn(const char *path)
35{
36	char *buf = xmalloc_readlink(path);
37	if (!buf) {
38		/* EINVAL => "file: Invalid argument" => puzzled user */
39		bb_error_msg("%s: cannot read link (not a symlink?)", path);
40	}
41	return buf;
42}
43
44/* UNUSED */
45