xref: /freebsd/lib/libc/gen/check_utility_compat.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
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("$FreeBSD$");
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 
50 int
51 check_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