check_utility_compat.c revision 114443 
1/*
2 * Copyright 2002 Massachusetts Institute of Technology
3 *
4 * Permission to use, copy, modify, and distribute this software and
5 * its documentation for any purpose and without fee is hereby
6 * granted, provided that both the above copyright notice and this
7 * permission notice appear in all copies, that both the above
8 * copyright notice and this permission notice appear in all
9 * supporting documentation, and that the name of M.I.T. not be used
10 * in advertising or publicity pertaining to distribution of the
11 * software without specific, written prior permission.  M.I.T. makes
12 * no representations about the suitability of this software for any
13 * purpose.  It is provided "as is" without express or implied
14 * warranty.
15 *
16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/lib/libc/gen/check_utility_compat.c 114443 2003-05-01 19:03:14Z nectar $");
32
33/*
34 * I din't use "namespace.h" here because none of the relevant utilities
35 * are threaded, so I'm not concerned about cancellation points or other
36 * niceties.
37 */
38#include <limits.h>
39#include <stdlib.h>
40#include <string.h>
41#include <unistd.h>
42
43#ifndef LINE_MAX
44#define	LINE_MAX _POSIX2_LINE_MAX
45#endif
46
47#define	_PATH_UTIL_COMPAT	"/etc/compat-FreeBSD-4-util"
48#define	_ENV_UTIL_COMPAT	"_COMPAT_FreeBSD_4"
49
50int
51check_utility_compat(const char *utility)
52{
53	char buf[LINE_MAX];
54	char *p, *bp;
55	int len;
56
57	if ((p = getenv(_ENV_UTIL_COMPAT)) != NULL) {
58		strlcpy(buf, p, sizeof buf);
59	} else {
60		if ((len = readlink(_PATH_UTIL_COMPAT, buf, sizeof buf)) < 0)
61			return 0;
62		if (len > sizeof buf)
63			len = sizeof buf;
64		buf[len] = '\0';
65	}
66	if (buf[0] == '\0')
67		return 1;
68
69	bp = buf;
70	while ((p = strsep(&bp, ",")) != NULL) {
71		if (strcmp(p, utility) == 0)
72			return 1;
73	}
74	return 0;
75}
76