xref: /freebsd/usr.bin/truss/setup.c (revision 501c4801edfcc2943eba8e4f8922436dd0f07dc8)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright 1997 Sean Eric Fagan
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by Sean Eric Fagan
17  * 4. Neither the name of the author may be used to endorse or promote
18  *    products derived from this software without specific prior written
19  *    permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 /*
36  * Various setup functions for truss.  Not the cleanest-written code,
37  * I'm afraid.
38  */
39 
40 #include <sys/ptrace.h>
41 #include <sys/sysctl.h>
42 #include <sys/time.h>
43 #include <sys/wait.h>
44 
45 #include <assert.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <signal.h>
49 #include <stdbool.h>
50 #include <stdint.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <sysdecode.h>
55 #include <time.h>
56 #include <unistd.h>
57 
58 #include "truss.h"
59 #include "syscall.h"
60 #include "extern.h"
61 
62 struct procabi_table {
63 	const char *name;
64 	struct procabi *abi;
65 };
66 
67 static sig_atomic_t detaching;
68 
69 static void	enter_syscall(struct trussinfo *, struct threadinfo *,
70 		    struct ptrace_lwpinfo *);
71 static void	new_proc(struct trussinfo *, pid_t, lwpid_t);
72 
73 
74 static struct procabi freebsd = {
75 	.type = "FreeBSD",
76 	.abi = SYSDECODE_ABI_FREEBSD,
77 	.pointer_size = sizeof(void *),
78 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(freebsd.extra_syscalls),
79 	.syscalls = { NULL }
80 };
81 
82 #if !defined(__SIZEOF_POINTER__)
83 #error "Use a modern compiler."
84 #endif
85 
86 #if __SIZEOF_POINTER__ > 4
87 static struct procabi freebsd32 = {
88 	.type = "FreeBSD32",
89 	.abi = SYSDECODE_ABI_FREEBSD32,
90 	.pointer_size = sizeof(uint32_t),
91 	.compat_prefix = "freebsd32_",
92 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(freebsd32.extra_syscalls),
93 	.syscalls = { NULL }
94 };
95 #endif
96 
97 static struct procabi linux = {
98 	.type = "Linux",
99 	.abi = SYSDECODE_ABI_LINUX,
100 	.pointer_size = sizeof(void *),
101 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(linux.extra_syscalls),
102 	.syscalls = { NULL }
103 };
104 
105 #if __SIZEOF_POINTER__ > 4
106 static struct procabi linux32 = {
107 	.type = "Linux32",
108 	.abi = SYSDECODE_ABI_LINUX32,
109 	.pointer_size = sizeof(uint32_t),
110 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(linux32.extra_syscalls),
111 	.syscalls = { NULL }
112 };
113 #endif
114 
115 static struct procabi_table abis[] = {
116 #if __SIZEOF_POINTER__ == 4
117 	{ "FreeBSD ELF32", &freebsd },
118 #elif __SIZEOF_POINTER__ == 8
119 	{ "FreeBSD ELF64", &freebsd },
120 	{ "FreeBSD ELF32", &freebsd32 },
121 #else
122 #error "Unsupported pointer size"
123 #endif
124 #if defined(__powerpc64__)
125 	{ "FreeBSD ELF64 V2", &freebsd },
126 #endif
127 #if defined(__amd64__)
128 	{ "FreeBSD a.out", &freebsd32 },
129 #endif
130 #if defined(__i386__)
131 	{ "FreeBSD a.out", &freebsd },
132 #endif
133 #if __SIZEOF_POINTER__ >= 8
134 	{ "Linux ELF64", &linux },
135 	{ "Linux ELF32", &linux32 },
136 #else
137 	{ "Linux ELF32", &linux },
138 #endif
139 };
140 
141 /*
142  * setup_and_wait() is called to start a process.  All it really does
143  * is fork(), enable tracing in the child, and then exec the given
144  * command.  At that point, the child process stops, and the parent
145  * can wake up and deal with it.
146  */
147 void
setup_and_wait(struct trussinfo * info,char * command[])148 setup_and_wait(struct trussinfo *info, char *command[])
149 {
150 	pid_t pid;
151 
152 	pid = vfork();
153 	if (pid == -1)
154 		err(1, "fork failed");
155 	if (pid == 0) {	/* Child */
156 		ptrace(PT_TRACE_ME, 0, 0, 0);
157 		execvp(command[0], command);
158 		err(1, "execvp %s", command[0]);
159 	}
160 
161 	/* Only in the parent here */
162 	if (waitpid(pid, NULL, 0) < 0)
163 		err(1, "unexpected stop in waitpid");
164 
165 	new_proc(info, pid, 0);
166 }
167 
168 /*
169  * start_tracing is called to attach to an existing process.
170  */
171 void
start_tracing(struct trussinfo * info,pid_t pid)172 start_tracing(struct trussinfo *info, pid_t pid)
173 {
174 	int ret, retry;
175 
176 	retry = 10;
177 	do {
178 		ret = ptrace(PT_ATTACH, pid, NULL, 0);
179 		usleep(200);
180 	} while (ret && retry-- > 0);
181 	if (ret)
182 		err(1, "Cannot attach to target process");
183 
184 	if (waitpid(pid, NULL, 0) < 0)
185 		err(1, "Unexpected stop in waitpid");
186 
187 	new_proc(info, pid, 0);
188 }
189 
190 /*
191  * Restore a process back to it's pre-truss state.
192  * Called for SIGINT, SIGTERM, SIGQUIT.  This only
193  * applies if truss was told to monitor an already-existing
194  * process.
195  */
196 void
restore_proc(int signo __unused)197 restore_proc(int signo __unused)
198 {
199 
200 	detaching = 1;
201 }
202 
203 static void
detach_proc(pid_t pid)204 detach_proc(pid_t pid)
205 {
206 	int sig, status;
207 
208 	/*
209 	 * Stop the child so that we can detach.  Filter out possible
210 	 * lingering SIGTRAP events buffered in the threads.
211 	 */
212 	kill(pid, SIGSTOP);
213 	for (;;) {
214 		if (waitpid(pid, &status, 0) < 0)
215 			err(1, "Unexpected error in waitpid");
216 		sig = WIFSTOPPED(status) ? WSTOPSIG(status) : 0;
217 		if (sig == SIGSTOP)
218 			break;
219 		if (sig == SIGTRAP)
220 			sig = 0;
221 		if (ptrace(PT_CONTINUE, pid, (caddr_t)1, sig) < 0)
222 			err(1, "Can not continue for detach");
223 	}
224 
225 	if (ptrace(PT_DETACH, pid, (caddr_t)1, 0) < 0)
226 		err(1, "Can not detach the process");
227 
228 	kill(pid, SIGCONT);
229 }
230 
231 /*
232  * Determine the ABI.  This is called after every exec, and when
233  * a process is first monitored.
234  */
235 static struct procabi *
find_abi(pid_t pid)236 find_abi(pid_t pid)
237 {
238 	size_t len;
239 	unsigned int i;
240 	int error;
241 	int mib[4];
242 	char progt[32];
243 
244 	len = sizeof(progt);
245 	mib[0] = CTL_KERN;
246 	mib[1] = KERN_PROC;
247 	mib[2] = KERN_PROC_SV_NAME;
248 	mib[3] = pid;
249 	error = sysctl(mib, 4, progt, &len, NULL, 0);
250 	if (error != 0)
251 		err(2, "can not get sysvec name");
252 
253 	for (i = 0; i < nitems(abis); i++) {
254 		if (strcmp(abis[i].name, progt) == 0)
255 			return (abis[i].abi);
256 	}
257 	warnx("ABI %s for pid %ld is not supported", progt, (long)pid);
258 	return (NULL);
259 }
260 
261 static struct threadinfo *
new_thread(struct procinfo * p,lwpid_t lwpid)262 new_thread(struct procinfo *p, lwpid_t lwpid)
263 {
264 	struct threadinfo *nt;
265 
266 	/*
267 	 * If this happens it means there is a bug in truss.  Unfortunately
268 	 * this will kill any processes truss is attached to.
269 	 */
270 	LIST_FOREACH(nt, &p->threadlist, entries) {
271 		if (nt->tid == lwpid)
272 			errx(1, "Duplicate thread for LWP %ld", (long)lwpid);
273 	}
274 
275 	nt = calloc(1, sizeof(struct threadinfo));
276 	if (nt == NULL)
277 		err(1, "calloc() failed");
278 	nt->proc = p;
279 	nt->tid = lwpid;
280 	LIST_INSERT_HEAD(&p->threadlist, nt, entries);
281 	return (nt);
282 }
283 
284 static void
free_thread(struct threadinfo * t)285 free_thread(struct threadinfo *t)
286 {
287 
288 	LIST_REMOVE(t, entries);
289 	free(t);
290 }
291 
292 static void
add_threads(struct trussinfo * info,struct procinfo * p)293 add_threads(struct trussinfo *info, struct procinfo *p)
294 {
295 	struct ptrace_lwpinfo pl;
296 	struct threadinfo *t;
297 	lwpid_t *lwps;
298 	int i, nlwps;
299 
300 	nlwps = ptrace(PT_GETNUMLWPS, p->pid, NULL, 0);
301 	if (nlwps == -1)
302 		err(1, "Unable to fetch number of LWPs");
303 	assert(nlwps > 0);
304 	lwps = calloc(nlwps, sizeof(*lwps));
305 	nlwps = ptrace(PT_GETLWPLIST, p->pid, (caddr_t)lwps, nlwps);
306 	if (nlwps == -1)
307 		err(1, "Unable to fetch LWP list");
308 	for (i = 0; i < nlwps; i++) {
309 		t = new_thread(p, lwps[i]);
310 		if (ptrace(PT_LWPINFO, lwps[i], (caddr_t)&pl, sizeof(pl)) == -1)
311 			err(1, "ptrace(PT_LWPINFO)");
312 		if (pl.pl_flags & PL_FLAG_SCE) {
313 			info->curthread = t;
314 			enter_syscall(info, t, &pl);
315 		}
316 	}
317 	free(lwps);
318 }
319 
320 static void
new_proc(struct trussinfo * info,pid_t pid,lwpid_t lwpid)321 new_proc(struct trussinfo *info, pid_t pid, lwpid_t lwpid)
322 {
323 	struct procinfo *np;
324 
325 	/*
326 	 * If this happens it means there is a bug in truss.  Unfortunately
327 	 * this will kill any processes truss is attached to.
328 	 */
329 	LIST_FOREACH(np, &info->proclist, entries) {
330 		if (np->pid == pid)
331 			errx(1, "Duplicate process for pid %ld", (long)pid);
332 	}
333 
334 	if (info->flags & FOLLOWFORKS)
335 		if (ptrace(PT_FOLLOW_FORK, pid, NULL, 1) == -1)
336 			err(1, "Unable to follow forks for pid %ld", (long)pid);
337 	if (ptrace(PT_LWP_EVENTS, pid, NULL, 1) == -1)
338 		err(1, "Unable to enable LWP events for pid %ld", (long)pid);
339 	np = calloc(1, sizeof(struct procinfo));
340 	np->pid = pid;
341 	np->abi = find_abi(pid);
342 	LIST_INIT(&np->threadlist);
343 	LIST_INSERT_HEAD(&info->proclist, np, entries);
344 
345 	if (lwpid != 0)
346 		new_thread(np, lwpid);
347 	else
348 		add_threads(info, np);
349 }
350 
351 static void
free_proc(struct procinfo * p)352 free_proc(struct procinfo *p)
353 {
354 	struct threadinfo *t, *t2;
355 
356 	LIST_FOREACH_SAFE(t, &p->threadlist, entries, t2) {
357 		free(t);
358 	}
359 	LIST_REMOVE(p, entries);
360 	free(p);
361 }
362 
363 static void
detach_all_procs(struct trussinfo * info)364 detach_all_procs(struct trussinfo *info)
365 {
366 	struct procinfo *p, *p2;
367 
368 	LIST_FOREACH_SAFE(p, &info->proclist, entries, p2) {
369 		detach_proc(p->pid);
370 		free_proc(p);
371 	}
372 }
373 
374 static struct procinfo *
find_proc(struct trussinfo * info,pid_t pid)375 find_proc(struct trussinfo *info, pid_t pid)
376 {
377 	struct procinfo *np;
378 
379 	LIST_FOREACH(np, &info->proclist, entries) {
380 		if (np->pid == pid)
381 			return (np);
382 	}
383 
384 	return (NULL);
385 }
386 
387 /*
388  * Change curthread member based on (pid, lwpid).
389  */
390 static void
find_thread(struct trussinfo * info,pid_t pid,lwpid_t lwpid)391 find_thread(struct trussinfo *info, pid_t pid, lwpid_t lwpid)
392 {
393 	struct procinfo *np;
394 	struct threadinfo *nt;
395 
396 	np = find_proc(info, pid);
397 	assert(np != NULL);
398 
399 	LIST_FOREACH(nt, &np->threadlist, entries) {
400 		if (nt->tid == lwpid) {
401 			info->curthread = nt;
402 			return;
403 		}
404 	}
405 	errx(1, "could not find thread");
406 }
407 
408 /*
409  * When a process exits, it should have exactly one thread left.
410  * All of the other threads should have reported thread exit events.
411  */
412 static void
find_exit_thread(struct trussinfo * info,pid_t pid)413 find_exit_thread(struct trussinfo *info, pid_t pid)
414 {
415 	struct procinfo *p;
416 
417 	p = find_proc(info, pid);
418 	assert(p != NULL);
419 
420 	info->curthread = LIST_FIRST(&p->threadlist);
421 	assert(info->curthread != NULL);
422 	assert(LIST_NEXT(info->curthread, entries) == NULL);
423 }
424 
425 static void
alloc_syscall(struct threadinfo * t,struct ptrace_lwpinfo * pl)426 alloc_syscall(struct threadinfo *t, struct ptrace_lwpinfo *pl)
427 {
428 	u_int i;
429 
430 	assert(t->in_syscall == 0);
431 	assert(t->cs.number == 0);
432 	assert(t->cs.sc == NULL);
433 	assert(t->cs.nargs == 0);
434 	for (i = 0; i < nitems(t->cs.s_args); i++)
435 		assert(t->cs.s_args[i] == NULL);
436 	memset(t->cs.args, 0, sizeof(t->cs.args));
437 	t->cs.number = pl->pl_syscall_code;
438 	t->in_syscall = 1;
439 }
440 
441 static void
free_syscall(struct threadinfo * t)442 free_syscall(struct threadinfo *t)
443 {
444 	u_int i;
445 
446 	for (i = 0; i < t->cs.nargs; i++)
447 		free(t->cs.s_args[i]);
448 	memset(&t->cs, 0, sizeof(t->cs));
449 	t->in_syscall = 0;
450 }
451 
452 static void
enter_syscall(struct trussinfo * info,struct threadinfo * t,struct ptrace_lwpinfo * pl)453 enter_syscall(struct trussinfo *info, struct threadinfo *t,
454     struct ptrace_lwpinfo *pl)
455 {
456 	struct syscall *sc;
457 	u_int i, narg;
458 
459 	alloc_syscall(t, pl);
460 	narg = MIN(pl->pl_syscall_narg, nitems(t->cs.args));
461 	if (narg != 0 && ptrace(PT_GET_SC_ARGS, t->tid, (caddr_t)t->cs.args,
462 	    sizeof(t->cs.args)) != 0) {
463 		free_syscall(t);
464 		return;
465 	}
466 
467 	sc = get_syscall(t, t->cs.number, narg);
468 	if (sc->unknown)
469 		fprintf(info->outfile, "-- UNKNOWN %s SYSCALL %d --\n",
470 		    t->proc->abi->type, t->cs.number);
471 
472 	t->cs.nargs = sc->decode.nargs;
473 	assert(sc->decode.nargs <= nitems(t->cs.s_args));
474 
475 	t->cs.sc = sc;
476 
477 	/*
478 	 * At this point, we set up the system call arguments.
479 	 * We ignore any OUT ones, however -- those are arguments that
480 	 * are set by the system call, and so are probably meaningless
481 	 * now.	This doesn't currently support arguments that are
482 	 * passed in *and* out, however.
483 	 */
484 #if DEBUG
485 	fprintf(stderr, "syscall %s(", sc->name);
486 #endif
487 	for (i = 0; i < t->cs.nargs; i++) {
488 #if DEBUG
489 		fprintf(stderr, "0x%lx%s",
490 		    t->cs.args[sc->decode.args[i].offset],
491 		    i < (t->cs.nargs - 1) ? "," : "");
492 #endif
493 		if (!(sc->decode.args[i].type & OUT)) {
494 			t->cs.s_args[i] = print_arg(&sc->decode.args[i],
495 			    t->cs.args, NULL, info);
496 		}
497 	}
498 #if DEBUG
499 	fprintf(stderr, ")\n");
500 #endif
501 
502 	clock_gettime(CLOCK_REALTIME, &t->before);
503 }
504 
505 /*
506  * When a thread exits voluntarily (including when a thread calls
507  * exit() to trigger a process exit), the thread's internal state
508  * holds the arguments passed to the exit system call.  When the
509  * thread's exit is reported, log that system call without a return
510  * value.
511  */
512 static void
thread_exit_syscall(struct trussinfo * info)513 thread_exit_syscall(struct trussinfo *info)
514 {
515 	struct threadinfo *t;
516 
517 	t = info->curthread;
518 	if (!t->in_syscall)
519 		return;
520 
521 	clock_gettime(CLOCK_REALTIME, &t->after);
522 
523 	print_syscall_ret(info, 0, NULL);
524 	free_syscall(t);
525 }
526 
527 static void
exit_syscall(struct trussinfo * info,struct ptrace_lwpinfo * pl)528 exit_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
529 {
530 	struct threadinfo *t;
531 	struct procinfo *p;
532 	struct syscall *sc;
533 	struct ptrace_sc_ret psr;
534 	u_int i;
535 
536 	t = info->curthread;
537 	if (!t->in_syscall)
538 		return;
539 
540 	clock_gettime(CLOCK_REALTIME, &t->after);
541 	p = t->proc;
542 	if (ptrace(PT_GET_SC_RET, t->tid, (caddr_t)&psr, sizeof(psr)) != 0) {
543 		free_syscall(t);
544 		return;
545 	}
546 
547 	sc = t->cs.sc;
548 	/*
549 	 * Here, we only look for arguments that have OUT masked in --
550 	 * otherwise, they were handled in enter_syscall().
551 	 */
552 	for (i = 0; i < sc->decode.nargs; i++) {
553 		char *temp;
554 
555 		if (sc->decode.args[i].type & OUT) {
556 			/*
557 			 * If an error occurred, then don't bother
558 			 * getting the data; it may not be valid.
559 			 */
560 			if (psr.sr_error != 0) {
561 				asprintf(&temp, "0x%lx",
562 				    (long)t->cs.args[sc->decode.args[i].offset]);
563 			} else {
564 				temp = print_arg(&sc->decode.args[i],
565 				    t->cs.args, psr.sr_retval, info);
566 			}
567 			t->cs.s_args[i] = temp;
568 		}
569 	}
570 
571 	print_syscall_ret(info, psr.sr_error, psr.sr_retval);
572 	free_syscall(t);
573 
574 	/*
575 	 * If the process executed a new image, check the ABI.  If the
576 	 * new ABI isn't supported, stop tracing this process.
577 	 */
578 	if (pl->pl_flags & PL_FLAG_EXEC) {
579 		assert(LIST_NEXT(LIST_FIRST(&p->threadlist), entries) == NULL);
580 		p->abi = find_abi(p->pid);
581 		if (p->abi == NULL) {
582 			if (ptrace(PT_DETACH, p->pid, (caddr_t)1, 0) < 0)
583 				err(1, "Can not detach the process");
584 			free_proc(p);
585 		}
586 	}
587 }
588 
589 int
print_line_prefix(struct trussinfo * info)590 print_line_prefix(struct trussinfo *info)
591 {
592 	struct timespec timediff;
593 	struct threadinfo *t;
594 	int len;
595 
596 	len = 0;
597 	t = info->curthread;
598 	if (info->flags & (FOLLOWFORKS | DISPLAYTIDS)) {
599 		if (info->flags & FOLLOWFORKS)
600 			len += fprintf(info->outfile, "%5d", t->proc->pid);
601 		if ((info->flags & (FOLLOWFORKS | DISPLAYTIDS)) ==
602 		    (FOLLOWFORKS | DISPLAYTIDS))
603 			len += fprintf(info->outfile, " ");
604 		if (info->flags & DISPLAYTIDS)
605 			len += fprintf(info->outfile, "%6d", t->tid);
606 		len += fprintf(info->outfile, ": ");
607 	}
608 	if (info->flags & ABSOLUTETIMESTAMPS) {
609 		timespecsub(&t->after, &info->start_time, &timediff);
610 		len += fprintf(info->outfile, "%jd.%09ld ",
611 		    (intmax_t)timediff.tv_sec, timediff.tv_nsec);
612 	}
613 	if (info->flags & RELATIVETIMESTAMPS) {
614 		timespecsub(&t->after, &t->before, &timediff);
615 		len += fprintf(info->outfile, "%jd.%09ld ",
616 		    (intmax_t)timediff.tv_sec, timediff.tv_nsec);
617 	}
618 	return (len);
619 }
620 
621 static void
report_thread_death(struct trussinfo * info)622 report_thread_death(struct trussinfo *info)
623 {
624 	struct threadinfo *t;
625 
626 	t = info->curthread;
627 	clock_gettime(CLOCK_REALTIME, &t->after);
628 	print_line_prefix(info);
629 	fprintf(info->outfile, "<thread %ld exited>\n", (long)t->tid);
630 }
631 
632 static void
report_thread_birth(struct trussinfo * info)633 report_thread_birth(struct trussinfo *info)
634 {
635 	struct threadinfo *t;
636 
637 	t = info->curthread;
638 	clock_gettime(CLOCK_REALTIME, &t->after);
639 	t->before = t->after;
640 	print_line_prefix(info);
641 	fprintf(info->outfile, "<new thread %ld>\n", (long)t->tid);
642 }
643 
644 static void
report_exit(struct trussinfo * info,siginfo_t * si)645 report_exit(struct trussinfo *info, siginfo_t *si)
646 {
647 	struct threadinfo *t;
648 
649 	t = info->curthread;
650 	clock_gettime(CLOCK_REALTIME, &t->after);
651 	print_line_prefix(info);
652 	if (si->si_code == CLD_EXITED)
653 		fprintf(info->outfile, "process exit, rval = %u\n",
654 		    si->si_status);
655 	else
656 		fprintf(info->outfile, "process killed, signal = %u%s\n",
657 		    si->si_status, si->si_code == CLD_DUMPED ?
658 		    " (core dumped)" : "");
659 }
660 
661 static void
report_new_child(struct trussinfo * info)662 report_new_child(struct trussinfo *info)
663 {
664 	struct threadinfo *t;
665 
666 	t = info->curthread;
667 	clock_gettime(CLOCK_REALTIME, &t->after);
668 	t->before = t->after;
669 	print_line_prefix(info);
670 	fprintf(info->outfile, "<new process>\n");
671 }
672 
673 void
decode_siginfo(FILE * fp,siginfo_t * si)674 decode_siginfo(FILE *fp, siginfo_t *si)
675 {
676 	const char *str;
677 
678 	fprintf(fp, " code=");
679 	str = sysdecode_sigcode(si->si_signo, si->si_code);
680 	if (str == NULL)
681 		fprintf(fp, "%d", si->si_code);
682 	else
683 		fprintf(fp, "%s", str);
684 	switch (si->si_code) {
685 	case SI_NOINFO:
686 		break;
687 	case SI_QUEUE:
688 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
689 		/* FALLTHROUGH */
690 	case SI_USER:
691 	case SI_LWP:
692 		fprintf(fp, " pid=%jd uid=%jd", (intmax_t)si->si_pid,
693 		    (intmax_t)si->si_uid);
694 		break;
695 	case SI_TIMER:
696 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
697 		fprintf(fp, " timerid=%d", si->si_timerid);
698 		fprintf(fp, " overrun=%d", si->si_overrun);
699 		if (si->si_errno != 0)
700 			fprintf(fp, " errno=%d", si->si_errno);
701 		break;
702 	case SI_ASYNCIO:
703 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
704 		break;
705 	case SI_MESGQ:
706 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
707 		fprintf(fp, " mqd=%d", si->si_mqd);
708 		break;
709 	default:
710 		switch (si->si_signo) {
711 		case SIGILL:
712 		case SIGFPE:
713 		case SIGSEGV:
714 		case SIGBUS:
715 			fprintf(fp, " trapno=%d", si->si_trapno);
716 			fprintf(fp, " addr=%p", si->si_addr);
717 			break;
718 		case SIGCHLD:
719 			fprintf(fp, " pid=%jd uid=%jd", (intmax_t)si->si_pid,
720 			    (intmax_t)si->si_uid);
721 			fprintf(fp, " status=%d", si->si_status);
722 			break;
723 		}
724 	}
725 }
726 
727 static void
report_signal(struct trussinfo * info,siginfo_t * si,struct ptrace_lwpinfo * pl)728 report_signal(struct trussinfo *info, siginfo_t *si, struct ptrace_lwpinfo *pl)
729 {
730 	struct threadinfo *t;
731 	const char *signame;
732 
733 	t = info->curthread;
734 	clock_gettime(CLOCK_REALTIME, &t->after);
735 	print_line_prefix(info);
736 	signame = sysdecode_signal(si->si_status);
737 	if (signame == NULL)
738 		signame = "?";
739 	fprintf(info->outfile, "SIGNAL %u (%s)", si->si_status, signame);
740 	if (pl->pl_event == PL_EVENT_SIGNAL && pl->pl_flags & PL_FLAG_SI)
741 		decode_siginfo(info->outfile, &pl->pl_siginfo);
742 	fprintf(info->outfile, "\n");
743 
744 }
745 
746 /*
747  * Wait for events until all the processes have exited or truss has been
748  * asked to stop.
749  */
750 void
eventloop(struct trussinfo * info)751 eventloop(struct trussinfo *info)
752 {
753 	struct ptrace_lwpinfo pl;
754 	siginfo_t si;
755 	int pending_signal;
756 
757 	while (!LIST_EMPTY(&info->proclist)) {
758 		if (detaching) {
759 			detach_all_procs(info);
760 			return;
761 		}
762 
763 		if (waitid(P_ALL, 0, &si, WTRAPPED | WEXITED) == -1) {
764 			if (errno == EINTR)
765 				continue;
766 			err(1, "Unexpected error from waitid");
767 		}
768 
769 		assert(si.si_signo == SIGCHLD);
770 
771 		switch (si.si_code) {
772 		case CLD_EXITED:
773 		case CLD_KILLED:
774 		case CLD_DUMPED:
775 			find_exit_thread(info, si.si_pid);
776 			if ((info->flags & COUNTONLY) == 0) {
777 				if (si.si_code == CLD_EXITED)
778 					thread_exit_syscall(info);
779 				report_exit(info, &si);
780 			}
781 			free_proc(info->curthread->proc);
782 			info->curthread = NULL;
783 			break;
784 		case CLD_TRAPPED:
785 			if (ptrace(PT_LWPINFO, si.si_pid, (caddr_t)&pl,
786 			    sizeof(pl)) == -1)
787 				err(1, "ptrace(PT_LWPINFO)");
788 
789 			if (pl.pl_flags & PL_FLAG_CHILD) {
790 				new_proc(info, si.si_pid, pl.pl_lwpid);
791 				assert(LIST_FIRST(&info->proclist)->abi !=
792 				    NULL);
793 			} else if (pl.pl_flags & PL_FLAG_BORN)
794 				new_thread(find_proc(info, si.si_pid),
795 				    pl.pl_lwpid);
796 			find_thread(info, si.si_pid, pl.pl_lwpid);
797 
798 			if (si.si_status == SIGTRAP &&
799 			    (pl.pl_flags & (PL_FLAG_BORN|PL_FLAG_EXITED|
800 			    PL_FLAG_SCE|PL_FLAG_SCX)) != 0) {
801 				if (pl.pl_flags & PL_FLAG_BORN) {
802 					if ((info->flags & COUNTONLY) == 0)
803 						report_thread_birth(info);
804 				} else if (pl.pl_flags & PL_FLAG_EXITED) {
805 					if ((info->flags & COUNTONLY) == 0)
806 						report_thread_death(info);
807 					free_thread(info->curthread);
808 					info->curthread = NULL;
809 				} else if (pl.pl_flags & PL_FLAG_SCE)
810 					enter_syscall(info, info->curthread, &pl);
811 				else if (pl.pl_flags & PL_FLAG_SCX)
812 					exit_syscall(info, &pl);
813 				pending_signal = 0;
814 			} else if (pl.pl_flags & PL_FLAG_CHILD) {
815 				if ((info->flags & COUNTONLY) == 0)
816 					report_new_child(info);
817 				pending_signal = 0;
818 			} else {
819 				if ((info->flags & NOSIGS) == 0)
820 					report_signal(info, &si, &pl);
821 				pending_signal = si.si_status;
822 			}
823 			ptrace(PT_SYSCALL, si.si_pid, (caddr_t)1,
824 			    pending_signal);
825 			break;
826 		case CLD_STOPPED:
827 			errx(1, "waitid reported CLD_STOPPED");
828 		case CLD_CONTINUED:
829 			break;
830 		}
831 	}
832 }
833