xref: /freebsd/usr.bin/cmp/regular.c (revision f66b9b40f403f7c30fec3c4ceed93c6e8fafa8ac)
19b50d902SRodney W. Grimes /*-
28a16b7a1SPedro F. Giffuni  * SPDX-License-Identifier: BSD-3-Clause
38a16b7a1SPedro F. Giffuni  *
49b50d902SRodney W. Grimes  * Copyright (c) 1991, 1993, 1994
59b50d902SRodney W. Grimes  *	The Regents of the University of California.  All rights reserved.
69b50d902SRodney W. Grimes  *
79b50d902SRodney W. Grimes  * Redistribution and use in source and binary forms, with or without
89b50d902SRodney W. Grimes  * modification, are permitted provided that the following conditions
99b50d902SRodney W. Grimes  * are met:
109b50d902SRodney W. Grimes  * 1. Redistributions of source code must retain the above copyright
119b50d902SRodney W. Grimes  *    notice, this list of conditions and the following disclaimer.
129b50d902SRodney W. Grimes  * 2. Redistributions in binary form must reproduce the above copyright
139b50d902SRodney W. Grimes  *    notice, this list of conditions and the following disclaimer in the
149b50d902SRodney W. Grimes  *    documentation and/or other materials provided with the distribution.
15fbbd9655SWarner Losh  * 3. Neither the name of the University nor the names of its contributors
169b50d902SRodney W. Grimes  *    may be used to endorse or promote products derived from this software
179b50d902SRodney W. Grimes  *    without specific prior written permission.
189b50d902SRodney W. Grimes  *
199b50d902SRodney W. Grimes  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
209b50d902SRodney W. Grimes  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
219b50d902SRodney W. Grimes  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
229b50d902SRodney W. Grimes  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
239b50d902SRodney W. Grimes  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
249b50d902SRodney W. Grimes  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
259b50d902SRodney W. Grimes  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
269b50d902SRodney W. Grimes  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
279b50d902SRodney W. Grimes  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
289b50d902SRodney W. Grimes  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
299b50d902SRodney W. Grimes  * SUCH DAMAGE.
309b50d902SRodney W. Grimes  */
319b50d902SRodney W. Grimes 
329f5b04e9SDavid Malone #if 0
339b50d902SRodney W. Grimes #ifndef lint
349f5b04e9SDavid Malone static char sccsid[] = "@(#)regular.c	8.3 (Berkeley) 4/2/94";
356af414cbSMark Murray #endif
369f5b04e9SDavid Malone #endif
379f5b04e9SDavid Malone 
389f5b04e9SDavid Malone #include <sys/cdefs.h>
399f5b04e9SDavid Malone __FBSDID("$FreeBSD$");
409b50d902SRodney W. Grimes 
419b50d902SRodney W. Grimes #include <sys/param.h>
429b50d902SRodney W. Grimes #include <sys/mman.h>
439b50d902SRodney W. Grimes #include <sys/stat.h>
449b50d902SRodney W. Grimes 
452528b7e2SMark Johnston #include <capsicum_helpers.h>
469b50d902SRodney W. Grimes #include <err.h>
479b50d902SRodney W. Grimes #include <limits.h>
48d4890512SDavid Schultz #include <signal.h>
499b50d902SRodney W. Grimes #include <stdlib.h>
509b50d902SRodney W. Grimes #include <stdio.h>
51c28065c6SJoerg Wunsch #include <unistd.h>
529b50d902SRodney W. Grimes 
539b50d902SRodney W. Grimes #include "extern.h"
549b50d902SRodney W. Grimes 
55f1bb2cd2SWarner Losh static u_char *remmap(u_char *, int, off_t);
56d4890512SDavid Schultz static void segv_handler(int);
5760b49f05SDavid Malone #define MMAP_CHUNK (8*1024*1024)
5860b49f05SDavid Malone 
59c28065c6SJoerg Wunsch #define ROUNDPAGE(i) ((i) & ~pagemask)
60c28065c6SJoerg Wunsch 
619b50d902SRodney W. Grimes void
62f2e8e0daSDavid Malone c_regular(int fd1, const char *file1, off_t skip1, off_t len1,
634e380e84SKyle Evans     int fd2, const char *file2, off_t skip2, off_t len2, off_t limit)
649b50d902SRodney W. Grimes {
652528b7e2SMark Johnston 	struct sigaction act, oact;
662528b7e2SMark Johnston 	cap_rights_t rights;
6760b49f05SDavid Malone 	u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
689b50d902SRodney W. Grimes 	off_t byte, length, line;
69c28065c6SJoerg Wunsch 	off_t pagemask, off1, off2;
70ac022265SBrian Feldman 	size_t pagesize;
712528b7e2SMark Johnston 	int dfound;
729b50d902SRodney W. Grimes 
739b50d902SRodney W. Grimes 	if (skip1 > len1)
749b50d902SRodney W. Grimes 		eofmsg(file1);
759b50d902SRodney W. Grimes 	len1 -= skip1;
769b50d902SRodney W. Grimes 	if (skip2 > len2)
779b50d902SRodney W. Grimes 		eofmsg(file2);
789b50d902SRodney W. Grimes 	len2 -= skip2;
799b50d902SRodney W. Grimes 
8084ad3d8fSBrian Feldman 	if (sflag && len1 != len2)
8184ad3d8fSBrian Feldman 		exit(DIFF_EXIT);
8284ad3d8fSBrian Feldman 
83ac022265SBrian Feldman 	pagesize = getpagesize();
84ac022265SBrian Feldman 	pagemask = (off_t)pagesize - 1;
85c28065c6SJoerg Wunsch 	off1 = ROUNDPAGE(skip1);
86c28065c6SJoerg Wunsch 	off2 = ROUNDPAGE(skip2);
87c28065c6SJoerg Wunsch 
889b50d902SRodney W. Grimes 	length = MIN(len1, len2);
894e380e84SKyle Evans 	if (limit > 0)
904e380e84SKyle Evans 		length = MIN(length, limit);
919b50d902SRodney W. Grimes 
9260b49f05SDavid Malone 	if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
934e380e84SKyle Evans 		c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
9460b49f05SDavid Malone 		return;
9560b49f05SDavid Malone 	}
962ae09ad8SJohn Dyson 
9760b49f05SDavid Malone 	if ((m2 = remmap(NULL, fd2, off2)) == NULL) {
9860b49f05SDavid Malone 		munmap(m1, MMAP_CHUNK);
994e380e84SKyle Evans 		c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
10060b49f05SDavid Malone 		return;
10160b49f05SDavid Malone 	}
1029b50d902SRodney W. Grimes 
1032528b7e2SMark Johnston 	if (caph_rights_limit(fd1, cap_rights_init(&rights, CAP_MMAP_R)) < 0)
1042528b7e2SMark Johnston 		err(1, "unable to limit rights for %s", file1);
1052528b7e2SMark Johnston 	if (caph_rights_limit(fd2, cap_rights_init(&rights, CAP_MMAP_R)) < 0)
1062528b7e2SMark Johnston 		err(1, "unable to limit rights for %s", file2);
1072528b7e2SMark Johnston 	if (caph_enter() < 0)
1082528b7e2SMark Johnston 		err(ERR_EXIT, "unable to enter capability mode");
1092528b7e2SMark Johnston 
1102528b7e2SMark Johnston 	sigemptyset(&act.sa_mask);
1112528b7e2SMark Johnston 	act.sa_flags = SA_NODEFER;
1122528b7e2SMark Johnston 	act.sa_handler = segv_handler;
1132528b7e2SMark Johnston 	if (sigaction(SIGSEGV, &act, &oact))
1142528b7e2SMark Johnston 		err(ERR_EXIT, "sigaction()");
1152528b7e2SMark Johnston 
1169b50d902SRodney W. Grimes 	dfound = 0;
11760b49f05SDavid Malone 	e1 = m1 + MMAP_CHUNK;
11860b49f05SDavid Malone 	e2 = m2 + MMAP_CHUNK;
11960b49f05SDavid Malone 	p1 = m1 + (skip1 - off1);
12060b49f05SDavid Malone 	p2 = m2 + (skip2 - off2);
12160b49f05SDavid Malone 
12260b49f05SDavid Malone 	for (byte = line = 1; length--; ++byte) {
12396846ff6SWarner Losh 		if ((ch = *p1) != *p2) {
124e03983a3SPoul-Henning Kamp 			if (xflag) {
125e03983a3SPoul-Henning Kamp 				dfound = 1;
1265748d9baSDavid Malone 				(void)printf("%08llx %02x %02x\n",
1275748d9baSDavid Malone 				    (long long)byte - 1, ch, *p2);
128e03983a3SPoul-Henning Kamp 			} else if (lflag) {
1299b50d902SRodney W. Grimes 				dfound = 1;
130*f66b9b40SKyle Evans 				if (bflag)
131*f66b9b40SKyle Evans 					(void)printf("%6lld %3o %c %3o %c\n",
132*f66b9b40SKyle Evans 					    (long long)byte, ch, ch, *p2, *p2);
133*f66b9b40SKyle Evans 				else
1345748d9baSDavid Malone 					(void)printf("%6lld %3o %3o\n",
1355748d9baSDavid Malone 					    (long long)byte, ch, *p2);
1369b50d902SRodney W. Grimes 			} else
137*f66b9b40SKyle Evans 				diffmsg(file1, file2, byte, line, ch, *p2);
1389b50d902SRodney W. Grimes 				/* NOTREACHED */
13996846ff6SWarner Losh 		}
1409b50d902SRodney W. Grimes 		if (ch == '\n')
1419b50d902SRodney W. Grimes 			++line;
14260b49f05SDavid Malone 		if (++p1 == e1) {
14360b49f05SDavid Malone 			off1 += MMAP_CHUNK;
14460b49f05SDavid Malone 			if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
14560b49f05SDavid Malone 				munmap(m2, MMAP_CHUNK);
14660b49f05SDavid Malone 				err(ERR_EXIT, "remmap %s", file1);
1479b50d902SRodney W. Grimes 			}
14860b49f05SDavid Malone 			e1 = m1 + MMAP_CHUNK;
14960b49f05SDavid Malone 		}
15060b49f05SDavid Malone 		if (++p2 == e2) {
15160b49f05SDavid Malone 			off2 += MMAP_CHUNK;
15260b49f05SDavid Malone 			if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
15360b49f05SDavid Malone 				munmap(m1, MMAP_CHUNK);
15460b49f05SDavid Malone 				err(ERR_EXIT, "remmap %s", file2);
15560b49f05SDavid Malone 			}
15660b49f05SDavid Malone 			e2 = m2 + MMAP_CHUNK;
15760b49f05SDavid Malone 		}
15860b49f05SDavid Malone 	}
15960b49f05SDavid Malone 	munmap(m1, MMAP_CHUNK);
16060b49f05SDavid Malone 	munmap(m2, MMAP_CHUNK);
1619b50d902SRodney W. Grimes 
162d4890512SDavid Schultz 	if (sigaction(SIGSEGV, &oact, NULL))
163d4890512SDavid Schultz 		err(ERR_EXIT, "sigaction()");
164d4890512SDavid Schultz 
1659b50d902SRodney W. Grimes 	if (len1 != len2)
1669b50d902SRodney W. Grimes 		eofmsg (len1 > len2 ? file2 : file1);
1679b50d902SRodney W. Grimes 	if (dfound)
1689b50d902SRodney W. Grimes 		exit(DIFF_EXIT);
1699b50d902SRodney W. Grimes }
17060b49f05SDavid Malone 
17160b49f05SDavid Malone static u_char *
172f2e8e0daSDavid Malone remmap(u_char *mem, int fd, off_t offset)
17360b49f05SDavid Malone {
17460b49f05SDavid Malone 	if (mem != NULL)
17560b49f05SDavid Malone 		munmap(mem, MMAP_CHUNK);
17660b49f05SDavid Malone 	mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
17760b49f05SDavid Malone 	if (mem == MAP_FAILED)
17860b49f05SDavid Malone 		return (NULL);
17960b49f05SDavid Malone 	madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
18060b49f05SDavid Malone 	return (mem);
18160b49f05SDavid Malone }
182d4890512SDavid Schultz 
183d4890512SDavid Schultz static void
184dd999839SPhilippe Charnier segv_handler(int sig __unused) {
185d4890512SDavid Schultz 	static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n";
186d4890512SDavid Schultz 
187d4890512SDavid Schultz 	write(STDERR_FILENO, msg, sizeof(msg));
188d4890512SDavid Schultz 	_exit(EXIT_FAILURE);
189d4890512SDavid Schultz }
190