ktrace.c revision 1.37 
1/*	$OpenBSD: ktrace.c,v 1.37 2020/07/16 17:47:41 tedu 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/param.h>	/* MAXCOMLEN */
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 <stdio.h>
45#include <string.h>
46#include <unistd.h>
47
48#include "ktrace.h"
49#include "extern.h"
50
51extern char *__progname;
52
53static int rpid(const char *);
54static void no_ktrace(int);
55static void usage(void);
56
57int	is_ltrace;
58
59int
60main(int argc, char *argv[])
61{
62	enum { NOTSET, CLEAR, CLEARALL } clear;
63	int append, ch, fd, inherit, ops, pidset, trpoints;
64	pid_t pid;
65	char *tracefile, *tracespec;
66	mode_t omask;
67	struct stat sb;
68
69	is_ltrace = strcmp(__progname, "ltrace") == 0;
70
71	clear = NOTSET;
72	append = ops = pidset = inherit = pid = 0;
73	trpoints = is_ltrace ? KTRFAC_USER : DEF_POINTS;
74	tracefile = DEF_TRACEFILE;
75	tracespec = NULL;
76
77	if (is_ltrace) {
78		while ((ch = getopt(argc, argv, "af:it:u:")) != -1)
79			switch ((char)ch) {
80			case 'a':
81				append = 1;
82				break;
83			case 'f':
84				tracefile = optarg;
85				break;
86			case 'i':
87				inherit = 1;
88				break;
89			case 't':
90				trpoints = getpoints(optarg, KTRFAC_USER);
91				if (trpoints < 0) {
92					warnx("unknown facility in %s", optarg);
93					usage();
94				}
95				break;
96			case 'u':
97				tracespec = optarg;
98				break;
99			default:
100				usage();
101			}
102	} else {
103		while ((ch = getopt(argc, argv, "aBCcdf:g:ip:t:T")) != -1)
104			switch ((char)ch) {
105			case 'a':
106				append = 1;
107				break;
108			case 'B':
109				putenv("LD_BIND_NOW=");
110				break;
111			case 'C':
112				clear = CLEARALL;
113				tracefile = NULL;
114				pidset = 1;
115				break;
116			case 'c':
117				clear = CLEAR;
118				break;
119			case 'd':
120				ops |= KTRFLAG_DESCEND;
121				break;
122			case 'f':
123				tracefile = optarg;
124				break;
125			case 'g':
126				pid = -rpid(optarg);
127				pidset = 1;
128				break;
129			case 'i':
130				inherit = 1;
131				break;
132			case 'p':
133				pid = rpid(optarg);
134				pidset = 1;
135				break;
136			case 't':
137				trpoints = getpoints(optarg, DEF_POINTS);
138				if (trpoints < 0) {
139					warnx("unknown facility in %s", optarg);
140					usage();
141				}
142				break;
143			case 'T':
144				putenv("LIBC_NOUSERTC=");
145				break;
146			default:
147				usage();
148			}
149	}
150
151	argv += optind;
152	argc -= optind;
153
154	if ((pidset && *argv) || (!pidset && !*argv && clear != CLEAR))
155		usage();
156
157	if (inherit)
158		trpoints |= KTRFAC_INHERIT;
159
160	(void)signal(SIGSYS, no_ktrace);
161	if (clear != NOTSET) {
162		if (clear == CLEARALL) {
163			ops = KTROP_CLEAR | KTRFLAG_DESCEND;
164			trpoints = ALL_POINTS;
165			pid = 1;
166		} else
167			ops |= pid ? KTROP_CLEAR : KTROP_CLEARFILE;
168
169		if (ktrace(tracefile, ops, trpoints, pid) == -1) {
170			if (errno == ESRCH)
171				err(1, "%d", pid);
172			err(1, "%s", tracefile);
173		}
174		exit(0);
175	}
176
177	omask = umask(S_IRWXG|S_IRWXO);
178	if (append) {
179		if ((fd = open(tracefile, O_CREAT | O_WRONLY, DEFFILEMODE)) == -1)
180			err(1, "%s", tracefile);
181		if (fstat(fd, &sb) != 0 || sb.st_uid != getuid())
182			errx(1, "Refuse to append to %s: not owned by you.",
183			    tracefile);
184	} else {
185		if (unlink(tracefile) == -1 && errno != ENOENT)
186			err(1, "unlink %s", tracefile);
187		if ((fd = open(tracefile, O_CREAT | O_EXCL | O_WRONLY,
188		    DEFFILEMODE)) == -1)
189			err(1, "%s", tracefile);
190	}
191	(void)umask(omask);
192	(void)close(fd);
193
194	if (*argv) {
195		if (is_ltrace) {
196			if (setenv("LD_TRACE_PLT", inherit ? "i" : "", 1) < 0)
197				err(1, "setenv(LD_TRACE_PLT)");
198			if (tracespec &&
199			    setenv("LD_TRACE_PLTSPEC", tracespec, 1) < 0)
200				err(1, "setenv(LD_TRACE_PLTSPEC)");
201		}
202		if (ktrace(tracefile, ops, trpoints, getpid()) == -1)
203			err(1, "%s", tracefile);
204		execvp(argv[0], &argv[0]);
205		err(1, "exec of '%s' failed", argv[0]);
206	}
207	else if (ktrace(tracefile, ops, trpoints, pid) == -1) {
208		if (errno == ESRCH)
209			err(1, "%d", pid);
210		err(1, "%s", tracefile);
211	}
212	exit(0);
213}
214
215static int
216rpid(const char *p)
217{
218	const char *errstr;
219	static int first;
220	pid_t pid;
221
222	if (first++) {
223		warnx("only one -g or -p flag is permitted.");
224		usage();
225	}
226	if (!*p) {
227		warnx("illegal process id.");
228		usage();
229	}
230	pid = strtonum(p, 1, INT_MAX, &errstr);
231	if (errstr) {
232		warnx("illegal process id: %s", errstr);
233		usage();
234	}
235	return pid;
236}
237
238static void
239usage(void)
240{
241	if (is_ltrace)
242		fprintf(stderr, "usage: %s [-ai] [-f trfile] [-t trstr]"
243		    " [-u trspec] command\n",
244		    __progname);
245	else
246		fprintf(stderr, "usage: %s [-aCcdi] [-f trfile] [-g pgid]"
247		    " [-p pid] [-t trstr]\n"
248		    "       %s [-aBdiT] [-f trfile] [-t trstr] command\n",
249		    __progname, __progname);
250	exit(1);
251}
252
253/* ARGSUSED */
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