ktrace.c revision 1.38 
1/*	$OpenBSD: ktrace.c,v 1.38 2021/09/01 15:54:40 deraadt 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/types.h>
35#include <sys/signal.h>
36#include <sys/stat.h>
37#include <sys/time.h>
38#include <sys/uio.h>
39#include <sys/ktrace.h>
40
41#include <err.h>
42#include <errno.h>
43#include <fcntl.h>
44#include <stdlib.h>
45#include <limits.h>
46#include <stdio.h>
47#include <string.h>
48#include <unistd.h>
49
50#include "ktrace.h"
51#include "extern.h"
52
53extern char *__progname;
54
55static int rpid(const char *);
56static void no_ktrace(int);
57static void usage(void);
58
59int	is_ltrace;
60
61int
62main(int argc, char *argv[])
63{
64	enum { NOTSET, CLEAR, CLEARALL } clear;
65	int append, ch, fd, inherit, ops, pidset, trpoints;
66	pid_t pid;
67	char *tracefile, *tracespec;
68	mode_t omask;
69	struct stat sb;
70
71	is_ltrace = strcmp(__progname, "ltrace") == 0;
72
73	clear = NOTSET;
74	append = ops = pidset = inherit = pid = 0;
75	trpoints = is_ltrace ? KTRFAC_USER : DEF_POINTS;
76	tracefile = DEF_TRACEFILE;
77	tracespec = NULL;
78
79	if (is_ltrace) {
80		while ((ch = getopt(argc, argv, "af:it:u:")) != -1)
81			switch ((char)ch) {
82			case 'a':
83				append = 1;
84				break;
85			case 'f':
86				tracefile = optarg;
87				break;
88			case 'i':
89				inherit = 1;
90				break;
91			case 't':
92				trpoints = getpoints(optarg, KTRFAC_USER);
93				if (trpoints < 0) {
94					warnx("unknown facility in %s", optarg);
95					usage();
96				}
97				break;
98			case 'u':
99				tracespec = optarg;
100				break;
101			default:
102				usage();
103			}
104	} else {
105		while ((ch = getopt(argc, argv, "aBCcdf:g:ip:t:T")) != -1)
106			switch ((char)ch) {
107			case 'a':
108				append = 1;
109				break;
110			case 'B':
111				putenv("LD_BIND_NOW=");
112				break;
113			case 'C':
114				clear = CLEARALL;
115				tracefile = NULL;
116				pidset = 1;
117				break;
118			case 'c':
119				clear = CLEAR;
120				break;
121			case 'd':
122				ops |= KTRFLAG_DESCEND;
123				break;
124			case 'f':
125				tracefile = optarg;
126				break;
127			case 'g':
128				pid = -rpid(optarg);
129				pidset = 1;
130				break;
131			case 'i':
132				inherit = 1;
133				break;
134			case 'p':
135				pid = rpid(optarg);
136				pidset = 1;
137				break;
138			case 't':
139				trpoints = getpoints(optarg, DEF_POINTS);
140				if (trpoints < 0) {
141					warnx("unknown facility in %s", optarg);
142					usage();
143				}
144				break;
145			case 'T':
146				putenv("LIBC_NOUSERTC=");
147				break;
148			default:
149				usage();
150			}
151	}
152
153	argv += optind;
154	argc -= optind;
155
156	if ((pidset && *argv) || (!pidset && !*argv && clear != CLEAR))
157		usage();
158
159	if (inherit)
160		trpoints |= KTRFAC_INHERIT;
161
162	(void)signal(SIGSYS, no_ktrace);
163	if (clear != NOTSET) {
164		if (clear == CLEARALL) {
165			ops = KTROP_CLEAR | KTRFLAG_DESCEND;
166			trpoints = ALL_POINTS;
167			pid = 1;
168		} else
169			ops |= pid ? KTROP_CLEAR : KTROP_CLEARFILE;
170
171		if (ktrace(tracefile, ops, trpoints, pid) == -1) {
172			if (errno == ESRCH)
173				err(1, "%d", pid);
174			err(1, "%s", tracefile);
175		}
176		exit(0);
177	}
178
179	omask = umask(S_IRWXG|S_IRWXO);
180	if (append) {
181		if ((fd = open(tracefile, O_CREAT | O_WRONLY, DEFFILEMODE)) == -1)
182			err(1, "%s", tracefile);
183		if (fstat(fd, &sb) != 0 || sb.st_uid != getuid())
184			errx(1, "Refuse to append to %s: not owned by you.",
185			    tracefile);
186	} else {
187		if (unlink(tracefile) == -1 && errno != ENOENT)
188			err(1, "unlink %s", tracefile);
189		if ((fd = open(tracefile, O_CREAT | O_EXCL | O_WRONLY,
190		    DEFFILEMODE)) == -1)
191			err(1, "%s", tracefile);
192	}
193	(void)umask(omask);
194	(void)close(fd);
195
196	if (*argv) {
197		if (is_ltrace) {
198			if (setenv("LD_TRACE_PLT", inherit ? "i" : "", 1) < 0)
199				err(1, "setenv(LD_TRACE_PLT)");
200			if (tracespec &&
201			    setenv("LD_TRACE_PLTSPEC", tracespec, 1) < 0)
202				err(1, "setenv(LD_TRACE_PLTSPEC)");
203		}
204		if (ktrace(tracefile, ops, trpoints, getpid()) == -1)
205			err(1, "%s", tracefile);
206		execvp(argv[0], &argv[0]);
207		err(1, "exec of '%s' failed", argv[0]);
208	}
209	else if (ktrace(tracefile, ops, trpoints, pid) == -1) {
210		if (errno == ESRCH)
211			err(1, "%d", pid);
212		err(1, "%s", tracefile);
213	}
214	exit(0);
215}
216
217static int
218rpid(const char *p)
219{
220	const char *errstr;
221	static int first;
222	pid_t pid;
223
224	if (first++) {
225		warnx("only one -g or -p flag is permitted.");
226		usage();
227	}
228	if (!*p) {
229		warnx("illegal process id.");
230		usage();
231	}
232	pid = strtonum(p, 1, INT_MAX, &errstr);
233	if (errstr) {
234		warnx("illegal process id: %s", errstr);
235		usage();
236	}
237	return pid;
238}
239
240static void
241usage(void)
242{
243	if (is_ltrace)
244		fprintf(stderr, "usage: %s [-ai] [-f trfile] [-t trstr]"
245		    " [-u trspec] command\n",
246		    __progname);
247	else
248		fprintf(stderr, "usage: %s [-aCcdi] [-f trfile] [-g pgid]"
249		    " [-p pid] [-t trstr]\n"
250		    "       %s [-aBdiT] [-f trfile] [-t trstr] command\n",
251		    __progname, __progname);
252	exit(1);
253}
254
255/* ARGSUSED */
256static void
257no_ktrace(int signo)
258{
259	dprintf(STDERR_FILENO,
260"error:\tktrace() system call not supported in the running kernel\n\tre-compile kernel with 'option KTRACE'\n");
261	_exit(1);
262}
263