xref: /freebsd/usr.bin/truss/main.c (revision bd81e07d2761cf1c13063eb49a5c0cb4a6951318)
1 /*-
2  * Copyright 1997 Sean Eric Fagan
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  * 3. All advertising materials mentioning features or use of this software
13  *    must display the following acknowledgement:
14  *	This product includes software developed by Sean Eric Fagan
15  * 4. Neither the name of the author may be used to endorse or promote
16  *    products derived from this software without specific prior written
17  *    permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 /*
36  * The main module for truss.  Surprisingly simple, but, then, the other
37  * files handle the bulk of the work.  And, of course, the kernel has to
38  * do a lot of the work :).
39  */
40 
41 #include <sys/param.h>
42 #include <sys/types.h>
43 #include <sys/time.h>
44 #include <sys/resource.h>
45 #include <sys/sysctl.h>
46 #include <sys/wait.h>
47 
48 #include <err.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <signal.h>
52 #include <stdint.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <time.h>
57 #include <unistd.h>
58 
59 #include "truss.h"
60 #include "extern.h"
61 #include "syscall.h"
62 
63 #define	MAXARGS	6
64 
65 static void
66 usage(void)
67 {
68 	fprintf(stderr, "%s\n%s\n",
69 	    "usage: truss [-cfaedDS] [-o file] [-s strsize] -p pid",
70 	    "       truss [-cfaedDS] [-o file] [-s strsize] command [args]");
71 	exit(1);
72 }
73 
74 /*
75  * WARNING! "FreeBSD a.out" must be first, or set_etype will not
76  * work correctly.
77  */
78 static struct ex_types {
79 	const char *type;
80 	void (*enter_syscall)(struct trussinfo *, int);
81 	long (*exit_syscall)(struct trussinfo *, int);
82 } ex_types[] = {
83 #ifdef __arm__
84 	{ "FreeBSD ELF32", arm_syscall_entry, arm_syscall_exit },
85 #endif
86 #ifdef __amd64__
87 	{ "FreeBSD ELF64", amd64_syscall_entry, amd64_syscall_exit },
88 	{ "FreeBSD ELF32", amd64_fbsd32_syscall_entry, amd64_fbsd32_syscall_exit },
89 	{ "Linux ELF32", amd64_linux32_syscall_entry, amd64_linux32_syscall_exit },
90 #endif
91 #ifdef __i386__
92 	{ "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit },
93 	{ "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit },
94 	{ "FreeBSD ELF32", i386_syscall_entry, i386_syscall_exit },
95 	{ "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit },
96 #endif
97 #ifdef __powerpc__
98 	{ "FreeBSD ELF", powerpc_syscall_entry, powerpc_syscall_exit },
99 	{ "FreeBSD ELF32", powerpc_syscall_entry, powerpc_syscall_exit },
100 #ifdef __powerpc64__
101 	{ "FreeBSD ELF64", powerpc64_syscall_entry, powerpc64_syscall_exit },
102 #endif
103 #endif
104 #ifdef __sparc64__
105 	{ "FreeBSD ELF64", sparc64_syscall_entry, sparc64_syscall_exit },
106 #endif
107 #ifdef __mips__
108 	{ "FreeBSD ELF", mips_syscall_entry, mips_syscall_exit },
109 	{ "FreeBSD ELF32", mips_syscall_entry, mips_syscall_exit },
110 	{ "FreeBSD ELF64", mips_syscall_entry, mips_syscall_exit }, // XXX
111 #endif
112 	{ 0, 0, 0 },
113 };
114 
115 /*
116  * Set the execution type.  This is called after every exec, and when
117  * a process is first monitored.
118  */
119 
120 static struct ex_types *
121 set_etype(struct trussinfo *trussinfo)
122 {
123 	struct ex_types *funcs;
124 	size_t len;
125 	int error;
126 	int mib[4];
127 	char progt[32];
128 
129 	len = sizeof(progt);
130 	mib[0] = CTL_KERN;
131 	mib[1] = KERN_PROC;
132 	mib[2] = KERN_PROC_SV_NAME;
133 	mib[3] = trussinfo->pid;
134 	error = sysctl(mib, 4, progt, &len, NULL, 0);
135 	if (error != 0)
136 		err(2, "can not get etype");
137 
138 	for (funcs = ex_types; funcs->type; funcs++)
139 		if (strcmp(funcs->type, progt) == 0)
140 			break;
141 
142 	if (funcs->type == NULL) {
143 		funcs = &ex_types[0];
144 		warn("execution type %s is not supported -- using %s",
145 		    progt, funcs->type);
146 	}
147 	return (funcs);
148 }
149 
150 char *
151 strsig(int sig)
152 {
153 	static char tmp[64];
154 
155 	if (sig > 0 && sig < NSIG) {
156 		snprintf(tmp, sizeof(tmp), "SIG%s", sys_signame[sig]);
157 		return (tmp);
158 	}
159 	return (NULL);
160 }
161 
162 int
163 main(int ac, char **av)
164 {
165 	struct timespec timediff;
166 	struct sigaction sa;
167 	struct ex_types *funcs;
168 	struct trussinfo *trussinfo;
169 	char *fname;
170 	char *signame;
171 	char **command;
172 	pid_t childpid;
173 	int c, initial_open, status;
174 
175 	fname = NULL;
176 	initial_open = 1;
177 
178 	/* Initialize the trussinfo struct */
179 	trussinfo = (struct trussinfo *)calloc(1, sizeof(struct trussinfo));
180 	if (trussinfo == NULL)
181 		errx(1, "calloc() failed");
182 
183 	trussinfo->outfile = stderr;
184 	trussinfo->strsize = 32;
185 	trussinfo->pr_why = S_NONE;
186 	trussinfo->curthread = NULL;
187 	SLIST_INIT(&trussinfo->threadlist);
188 	while ((c = getopt(ac, av, "p:o:facedDs:S")) != -1) {
189 		switch (c) {
190 		case 'p':	/* specified pid */
191 			trussinfo->pid = atoi(optarg);
192 			/* make sure i don't trace me */
193 			if (trussinfo->pid == getpid()) {
194 				fprintf(stderr, "attempt to grab self.\n");
195 				exit(2);
196 			}
197 			break;
198 		case 'f': /* Follow fork()'s */
199 			trussinfo->flags |= FOLLOWFORKS;
200 			break;
201 		case 'a': /* Print execve() argument strings. */
202 			trussinfo->flags |= EXECVEARGS;
203 			break;
204 		case 'c': /* Count number of system calls and time. */
205 			trussinfo->flags |= COUNTONLY;
206 			break;
207 		case 'e': /* Print execve() environment strings. */
208 			trussinfo->flags |= EXECVEENVS;
209 			break;
210 		case 'd': /* Absolute timestamps */
211 			trussinfo->flags |= ABSOLUTETIMESTAMPS;
212 			break;
213 		case 'D': /* Relative timestamps */
214 			trussinfo->flags |= RELATIVETIMESTAMPS;
215 			break;
216 		case 'o':	/* Specified output file */
217 			fname = optarg;
218 			break;
219 		case 's':	/* Specified string size */
220 			trussinfo->strsize = atoi(optarg);
221 			break;
222 		case 'S':	/* Don't trace signals */
223 			trussinfo->flags |= NOSIGS;
224 			break;
225 		default:
226 			usage();
227 		}
228 	}
229 
230 	ac -= optind; av += optind;
231 	if ((trussinfo->pid == 0 && ac == 0) ||
232 	    (trussinfo->pid != 0 && ac != 0))
233 		usage();
234 
235 	if (fname != NULL) { /* Use output file */
236 		/*
237 		 * Set close-on-exec ('e'), so that the output file is not
238 		 * shared with the traced process.
239 		 */
240 		if ((trussinfo->outfile = fopen(fname, "we")) == NULL)
241 			err(1, "cannot open %s", fname);
242 	}
243 
244 	/*
245 	 * If truss starts the process itself, it will ignore some signals --
246 	 * they should be passed off to the process, which may or may not
247 	 * exit.  If, however, we are examining an already-running process,
248 	 * then we restore the event mask on these same signals.
249 	 */
250 
251 	if (trussinfo->pid == 0) {	/* Start a command ourselves */
252 		command = av;
253 		trussinfo->pid = setup_and_wait(command);
254 		signal(SIGINT, SIG_IGN);
255 		signal(SIGTERM, SIG_IGN);
256 		signal(SIGQUIT, SIG_IGN);
257 	} else {
258 		sa.sa_handler = restore_proc;
259 		sa.sa_flags = 0;
260 		sigemptyset(&sa.sa_mask);
261 		sigaction(SIGINT, &sa, NULL);
262 		sigaction(SIGQUIT, &sa, NULL);
263 		sigaction(SIGTERM, &sa, NULL);
264 		start_tracing(trussinfo->pid);
265 	}
266 
267 
268 	/*
269 	 * At this point, if we started the process, it is stopped waiting to
270 	 * be woken up, either in exit() or in execve().
271 	 */
272 
273 START_TRACE:
274 	funcs = set_etype(trussinfo);
275 
276 	initial_open = 0;
277 	/*
278 	 * At this point, it's a simple loop, waiting for the process to
279 	 * stop, finding out why, printing out why, and then continuing it.
280 	 * All of the grunt work is done in the support routines.
281 	 */
282 
283 	clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);
284 
285 	do {
286 		waitevent(trussinfo);
287 
288 		switch (trussinfo->pr_why) {
289 		case S_SCE:
290 			funcs->enter_syscall(trussinfo, MAXARGS);
291 			clock_gettime(CLOCK_REALTIME,
292 			    &trussinfo->curthread->before);
293 			break;
294 		case S_SCX:
295 			clock_gettime(CLOCK_REALTIME,
296 			    &trussinfo->curthread->after);
297 
298 			if (trussinfo->curthread->in_fork &&
299 			    (trussinfo->flags & FOLLOWFORKS)) {
300 				trussinfo->curthread->in_fork = 0;
301 				childpid = funcs->exit_syscall(trussinfo,
302 				    trussinfo->pr_data);
303 
304 				/*
305 				 * Fork a new copy of ourself to trace
306 				 * the child of the original traced
307 				 * process.
308 				 */
309 				if (fork() == 0) {
310 					trussinfo->pid = childpid;
311 					start_tracing(trussinfo->pid);
312 					goto START_TRACE;
313 				}
314 				break;
315 			}
316 			funcs->exit_syscall(trussinfo, MAXARGS);
317 			break;
318 		case S_SIG:
319 			if (trussinfo->flags & NOSIGS)
320 				break;
321 			if (trussinfo->flags & FOLLOWFORKS)
322 				fprintf(trussinfo->outfile, "%5d: ",
323 				    trussinfo->pid);
324 			if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
325 				timespecsubt(&trussinfo->curthread->after,
326 				    &trussinfo->start_time, &timediff);
327 				fprintf(trussinfo->outfile, "%jd.%09ld ",
328 				    (intmax_t)timediff.tv_sec,
329 				    timediff.tv_nsec);
330 			}
331 			if (trussinfo->flags & RELATIVETIMESTAMPS) {
332 				timespecsubt(&trussinfo->curthread->after,
333 				    &trussinfo->curthread->before, &timediff);
334 				fprintf(trussinfo->outfile, "%jd.%09ld ",
335 				    (intmax_t)timediff.tv_sec,
336 				    timediff.tv_nsec);
337 			}
338 			signame = strsig(trussinfo->pr_data);
339 			fprintf(trussinfo->outfile,
340 			    "SIGNAL %u (%s)\n", trussinfo->pr_data,
341 			    signame == NULL ? "?" : signame);
342 			break;
343 		case S_EXIT:
344 			if (trussinfo->flags & COUNTONLY)
345 				break;
346 			if (trussinfo->flags & FOLLOWFORKS)
347 				fprintf(trussinfo->outfile, "%5d: ",
348 				    trussinfo->pid);
349 			if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
350 				timespecsubt(&trussinfo->curthread->after,
351 				    &trussinfo->start_time, &timediff);
352 				fprintf(trussinfo->outfile, "%jd.%09ld ",
353 				    (intmax_t)timediff.tv_sec,
354 				    timediff.tv_nsec);
355 			}
356 			if (trussinfo->flags & RELATIVETIMESTAMPS) {
357 				timespecsubt(&trussinfo->curthread->after,
358 				    &trussinfo->curthread->before, &timediff);
359 				fprintf(trussinfo->outfile, "%jd.%09ld ",
360 				    (intmax_t)timediff.tv_sec,
361 				    timediff.tv_nsec);
362 			}
363 			fprintf(trussinfo->outfile,
364 			    "process exit, rval = %u\n", trussinfo->pr_data);
365 			break;
366 		default:
367 			break;
368 		}
369 	} while (trussinfo->pr_why != S_EXIT &&
370 	    trussinfo->pr_why != S_DETACHED);
371 
372 	if (trussinfo->flags & FOLLOWFORKS) {
373 		do {
374 			childpid = wait(&status);
375 		} while (childpid != -1);
376 	}
377 
378 	if (trussinfo->flags & COUNTONLY)
379 		print_summary(trussinfo);
380 
381 	fflush(trussinfo->outfile);
382 
383 	return (0);
384 }
385