1/*	$OpenBSD: ktrace.c,v 1.40 2023/03/08 04:43:11 guenther Exp $	*/
2/*	$NetBSD: ktrace.c,v 1.4 1995/08/31 23:01:44 jtc Exp $	*/
3
4/*-
5 * Copyright (c) 1988, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/types.h>
34#include <sys/signal.h>
35#include <sys/stat.h>
36#include <sys/time.h>
37#include <sys/uio.h>
38#include <sys/ktrace.h>
39
40#include <err.h>
41#include <errno.h>
42#include <fcntl.h>
43#include <stdlib.h>
44#include <limits.h>
45#include <stdio.h>
46#include <string.h>
47#include <unistd.h>
48
49#include "ktrace.h"
50#include "extern.h"
51
52extern char *__progname;
53
54static int rpid(const char *);
55static void no_ktrace(int);
56static void usage(void);
57
58int	is_ltrace;
59
60int
61main(int argc, char *argv[])
62{
63	enum { NOTSET, CLEAR, CLEARALL } clear;
64	int append, ch, fd, inherit, ops, pidset, trpoints;
65	pid_t pid;
66	char *tracefile, *tracespec;
67	mode_t omask;
68	struct stat sb;
69
70	is_ltrace = strcmp(__progname, "ltrace") == 0;
71
72	clear = NOTSET;
73	append = ops = pidset = inherit = pid = 0;
74	trpoints = is_ltrace ? KTRFAC_USER : DEF_POINTS;
75	tracefile = DEF_TRACEFILE;
76	tracespec = NULL;
77
78	if (is_ltrace) {
79		while ((ch = getopt(argc, argv, "af:it:u:")) != -1)
80			switch ((char)ch) {
81			case 'a':
82				append = 1;
83				break;
84			case 'f':
85				tracefile = optarg;
86				break;
87			case 'i':
88				inherit = 1;
89				break;
90			case 't':
91				trpoints = getpoints(optarg, KTRFAC_USER);
92				if (trpoints < 0) {
93					warnx("unknown facility in %s", optarg);
94					usage();
95				}
96				break;
97			case 'u':
98				tracespec = optarg;
99				break;
100			default:
101				usage();
102			}
103	} else {
104		while ((ch = getopt(argc, argv, "aBCcdf:g:ip:t:T")) != -1)
105			switch ((char)ch) {
106			case 'a':
107				append = 1;
108				break;
109			case 'B':
110				putenv("LD_BIND_NOW=");
111				break;
112			case 'C':
113				clear = CLEARALL;
114				tracefile = NULL;
115				pidset = 1;
116				break;
117			case 'c':
118				clear = CLEAR;
119				break;
120			case 'd':
121				ops |= KTRFLAG_DESCEND;
122				break;
123			case 'f':
124				tracefile = optarg;
125				break;
126			case 'g':
127				pid = -rpid(optarg);
128				pidset = 1;
129				break;
130			case 'i':
131				inherit = 1;
132				break;
133			case 'p':
134				pid = rpid(optarg);
135				pidset = 1;
136				break;
137			case 't':
138				trpoints = getpoints(optarg, DEF_POINTS);
139				if (trpoints < 0) {
140					warnx("unknown facility in %s", optarg);
141					usage();
142				}
143				break;
144			case 'T':
145				putenv("LIBC_NOUSERTC=");
146				break;
147			default:
148				usage();
149			}
150	}
151
152	argv += optind;
153	argc -= optind;
154
155	if ((pidset && *argv) || (!pidset && !*argv && clear != CLEAR))
156		usage();
157
158	if (inherit)
159		trpoints |= KTRFAC_INHERIT;
160
161	(void)signal(SIGSYS, no_ktrace);
162	if (clear != NOTSET) {
163		if (clear == CLEARALL) {
164			ops = KTROP_CLEAR | KTRFLAG_DESCEND;
165			trpoints = ALL_POINTS;
166			pid = 1;
167		} else
168			ops |= pid ? KTROP_CLEAR : KTROP_CLEARFILE;
169
170		if (ktrace(tracefile, ops, trpoints, pid) == -1) {
171			if (errno == ESRCH)
172				err(1, "%d", pid);
173			err(1, "%s", tracefile);
174		}
175		exit(0);
176	}
177
178	omask = umask(S_IRWXG|S_IRWXO);
179	if (append) {
180		if ((fd = open(tracefile, O_CREAT | O_WRONLY, DEFFILEMODE)) == -1)
181			err(1, "%s", tracefile);
182		if (fstat(fd, &sb) != 0 || sb.st_uid != getuid())
183			errx(1, "Refuse to append to %s: not owned by you.",
184			    tracefile);
185	} else {
186		if (unlink(tracefile) == -1 && errno != ENOENT)
187			err(1, "unlink %s", tracefile);
188		if ((fd = open(tracefile, O_CREAT | O_EXCL | O_WRONLY,
189		    DEFFILEMODE)) == -1)
190			err(1, "%s", tracefile);
191	}
192	(void)umask(omask);
193	(void)close(fd);
194
195	if (*argv) {
196		if (is_ltrace) {
197			if (setenv("LD_TRACE_PLT", inherit ? "i" : "", 1) < 0)
198				err(1, "setenv(LD_TRACE_PLT)");
199			if (tracespec &&
200			    setenv("LD_TRACE_PLTSPEC", tracespec, 1) < 0)
201				err(1, "setenv(LD_TRACE_PLTSPEC)");
202		}
203		if (ktrace(tracefile, ops, trpoints, getpid()) == -1)
204			err(1, "%s", tracefile);
205		execvp(argv[0], &argv[0]);
206		err(1, "exec of '%s' failed", argv[0]);
207	}
208	else if (ktrace(tracefile, ops, trpoints, pid) == -1) {
209		if (errno == ESRCH)
210			err(1, "%d", pid);
211		err(1, "%s", tracefile);
212	}
213	exit(0);
214}
215
216static int
217rpid(const char *p)
218{
219	const char *errstr;
220	static int first;
221	pid_t pid;
222
223	if (first++) {
224		warnx("only one -g or -p flag is permitted.");
225		usage();
226	}
227	if (!*p) {
228		warnx("illegal process id.");
229		usage();
230	}
231	pid = strtonum(p, 1, INT_MAX, &errstr);
232	if (errstr) {
233		warnx("illegal process id: %s", errstr);
234		usage();
235	}
236	return pid;
237}
238
239static void
240usage(void)
241{
242	if (is_ltrace)
243		fprintf(stderr, "usage: %s [-ai] [-f trfile] [-t trstr]"
244		    " [-u trspec] command\n",
245		    __progname);
246	else
247		fprintf(stderr, "usage: %s [-aCcdi] [-f trfile] [-g pgid]"
248		    " [-p pid] [-t trstr]\n"
249		    "       %s [-aBdiT] [-f trfile] [-t trstr] command\n",
250		    __progname, __progname);
251	exit(1);
252}
253
254static void
255no_ktrace(int signo)
256{
257	dprintf(STDERR_FILENO,
258"error:\tktrace() system call not supported in the running kernel\n\tre-compile kernel with 'option KTRACE'\n");
259	_exit(1);
260}
261