xref: /freebsd/usr.bin/ktrace/ktrace.c (revision 61ba55bcf70f2340f9c943c9571113b3fd8eda69)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1988, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n";
36 #endif /* not lint */
37 
38 #if 0
39 #ifndef lint
40 static char sccsid[] = "@(#)ktrace.c	8.1 (Berkeley) 6/6/93";
41 #endif /* not lint */
42 #endif
43 
44 #include <sys/cdefs.h>
45 #include <sys/param.h>
46 #include <sys/file.h>
47 #include <sys/stat.h>
48 #include <sys/time.h>
49 #include <sys/uio.h>
50 #include <sys/ktrace.h>
51 
52 #include <err.h>
53 #include <errno.h>
54 #include <inttypes.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <unistd.h>
58 
59 #include "ktrace.h"
60 
61 static char def_tracefile[] = DEF_TRACEFILE;
62 
63 static enum clear { NOTSET, CLEAR, CLEARALL } clear = NOTSET;
64 static int pid;
65 
66 static void no_ktrace(int);
67 static void set_pid_clear(const char *, enum clear);
68 static void usage(void) __dead2;
69 
70 int
71 main(int argc, char *argv[])
72 {
73 	int append, ch, fd, inherit, ops, trpoints;
74 	const char *tracefile;
75 	mode_t omask;
76 	struct stat sb;
77 
78 	append = ops = inherit = 0;
79 	trpoints = DEF_POINTS;
80 	tracefile = def_tracefile;
81 	while ((ch = getopt(argc,argv,"aCcdf:g:ip:t:")) != -1)
82 		switch((char)ch) {
83 		case 'a':
84 			append = 1;
85 			break;
86 		case 'C':
87 			set_pid_clear("1", CLEARALL);
88 			break;
89 		case 'c':
90 			set_pid_clear(NULL, CLEAR);
91 			break;
92 		case 'd':
93 			ops |= KTRFLAG_DESCEND;
94 			break;
95 		case 'f':
96 			tracefile = optarg;
97 			break;
98 		case 'g':
99 			set_pid_clear(optarg, NOTSET);
100 			pid = -pid;
101 			break;
102 		case 'i':
103 			inherit = 1;
104 			break;
105 		case 'p':
106 			set_pid_clear(optarg, NOTSET);
107 			break;
108 		case 't':
109 			trpoints = getpoints(optarg);
110 			if (trpoints < 0) {
111 				warnx("unknown facility in %s", optarg);
112 				usage();
113 			}
114 			break;
115 		default:
116 			usage();
117 		}
118 
119 	argv += optind;
120 	argc -= optind;
121 
122 	/* must have either -[Cc], a pid or a command */
123 	if (clear == NOTSET && pid == 0 && argc == 0)
124 		usage();
125 	/* can't have both a pid and a command */
126 	/* (note that -C sets pid to 1) */
127 	if (pid != 0 && argc > 0) {
128 		usage();
129 	}
130 
131 	if (inherit)
132 		trpoints |= KTRFAC_INHERIT;
133 
134 	(void)signal(SIGSYS, no_ktrace);
135 	if (clear != NOTSET) {
136 		if (clear == CLEARALL) {
137 			ops = KTROP_CLEAR | KTRFLAG_DESCEND;
138 			trpoints = ALL_POINTS;
139 		} else {
140 			ops |= pid ? KTROP_CLEAR : KTROP_CLEARFILE;
141 		}
142 		if (ktrace(tracefile, ops, trpoints, pid) < 0)
143 			err(1, "%s", tracefile);
144 		exit(0);
145 	}
146 
147 	omask = umask(S_IRWXG|S_IRWXO);
148 	if (append) {
149 		if ((fd = open(tracefile, O_CREAT | O_WRONLY | O_NONBLOCK,
150 		    DEFFILEMODE)) < 0)
151 			err(1, "%s", tracefile);
152 		if (fstat(fd, &sb) != 0 || sb.st_uid != getuid())
153 			errx(1, "refuse to append to %s not owned by you",
154 			    tracefile);
155 		if (!(S_ISREG(sb.st_mode)))
156 			errx(1, "%s not regular file", tracefile);
157 	} else {
158 		if (unlink(tracefile) == -1 && errno != ENOENT)
159 			err(1, "unlink %s", tracefile);
160 		if ((fd = open(tracefile, O_CREAT | O_EXCL | O_WRONLY,
161 		    DEFFILEMODE)) < 0)
162 			err(1, "%s", tracefile);
163 	}
164 	(void)umask(omask);
165 	(void)close(fd);
166 
167 	trpoints |= PROC_ABI_POINTS;
168 
169 	if (argc > 0) {
170 		if (ktrace(tracefile, ops, trpoints, getpid()) < 0)
171 			err(1, "%s", tracefile);
172 		execvp(*argv, argv);
173 		err(1, "exec of '%s' failed", *argv);
174 	}
175 	if (ktrace(tracefile, ops, trpoints, pid) < 0)
176 		err(1, "%s", tracefile);
177 	exit(0);
178 }
179 
180 static void
181 set_pid_clear(const char *p, enum clear cl)
182 {
183 	intmax_t n;
184 	char *e;
185 
186 	if (clear != NOTSET && cl != NOTSET) {
187 		/* either -c and -C or either of them twice */
188 		warnx("only one -c or -C flag is permitted");
189 		usage();
190 	}
191 	if ((clear == CLEARALL && p != NULL) || (cl == CLEARALL && pid != 0)) {
192 		/* both -C and a pid or pgid */
193 		warnx("the -C flag may not be combined with -g or -p");
194 		usage();
195 	}
196 	if (p != NULL && pid != 0) {
197 		/* either -p and -g or either of them twice */
198 		warnx("only one -g or -p flag is permitted");
199 		usage();
200 	}
201 	if (p != NULL) {
202 		errno = 0;
203 		n = strtoimax(p, &e, 10);
204 		/*
205 		 * 1) not a number, or outside the range of an intmax_t
206 		 * 2) inside the range of intmax_t but outside the range
207 		 *    of an int, keeping in mind that the pid may be
208 		 *    negated if it's actually a pgid.
209 		 */
210 		if (*e != '\0' || n < 1 || errno == ERANGE ||
211 		    n > (intmax_t)INT_MAX || n > -(intmax_t)INT_MIN) {
212 			warnx("invalid process or group id");
213 			usage();
214 		}
215 		pid = n;
216 	}
217 	if (cl != NOTSET)
218 		if ((clear = cl) == CLEARALL)
219 			pid = 1;
220 }
221 
222 static void
223 usage(void)
224 {
225 
226 	fprintf(stderr, "%s\n%s\n",
227 	    "usage: ktrace [-aCcdi] [-f trfile] [-g pgrp | -p pid] [-t trstr]",
228 	    "       ktrace [-adi] [-f trfile] [-t trstr] command");
229 	exit(1);
230 }
231 
232 static void
233 no_ktrace(int sig __unused)
234 {
235 
236 	fprintf(stderr, "error:\t%s\n\t%s\n",
237 	    "ktrace() system call not supported in the running kernel",
238 	    "re-compile kernel with 'options KTRACE'");
239         exit(1);
240 }
241