xref: /freebsd/usr.bin/truss/setup.c (revision b3e7694832e81d7a904a10f525f8797b753bf0d3)
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 __FBSDID("$FreeBSD$");
36 
37 /*
38  * Various setup functions for truss.  Not the cleanest-written code,
39  * I'm afraid.
40  */
41 
42 #include <sys/ptrace.h>
43 #include <sys/sysctl.h>
44 #include <sys/time.h>
45 #include <sys/wait.h>
46 
47 #include <assert.h>
48 #include <err.h>
49 #include <errno.h>
50 #include <signal.h>
51 #include <stdbool.h>
52 #include <stdint.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <sysdecode.h>
57 #include <time.h>
58 #include <unistd.h>
59 
60 #include "truss.h"
61 #include "syscall.h"
62 #include "extern.h"
63 
64 struct procabi_table {
65 	const char *name;
66 	struct procabi *abi;
67 };
68 
69 static sig_atomic_t detaching;
70 
71 static void	enter_syscall(struct trussinfo *, struct threadinfo *,
72 		    struct ptrace_lwpinfo *);
73 static void	new_proc(struct trussinfo *, pid_t, lwpid_t);
74 
75 
76 static struct procabi freebsd = {
77 	.type = "FreeBSD",
78 	.abi = SYSDECODE_ABI_FREEBSD,
79 	.pointer_size = sizeof(void *),
80 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(freebsd.extra_syscalls),
81 	.syscalls = { NULL }
82 };
83 
84 #if !defined(__SIZEOF_POINTER__)
85 #error "Use a modern compiler."
86 #endif
87 
88 #if __SIZEOF_POINTER__ > 4
89 static struct procabi freebsd32 = {
90 	.type = "FreeBSD32",
91 	.abi = SYSDECODE_ABI_FREEBSD32,
92 	.pointer_size = sizeof(uint32_t),
93 	.compat_prefix = "freebsd32_",
94 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(freebsd32.extra_syscalls),
95 	.syscalls = { NULL }
96 };
97 #endif
98 
99 static struct procabi linux = {
100 	.type = "Linux",
101 	.abi = SYSDECODE_ABI_LINUX,
102 	.pointer_size = sizeof(void *),
103 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(linux.extra_syscalls),
104 	.syscalls = { NULL }
105 };
106 
107 #if __SIZEOF_POINTER__ > 4
108 static struct procabi linux32 = {
109 	.type = "Linux32",
110 	.abi = SYSDECODE_ABI_LINUX32,
111 	.pointer_size = sizeof(uint32_t),
112 	.extra_syscalls = STAILQ_HEAD_INITIALIZER(linux32.extra_syscalls),
113 	.syscalls = { NULL }
114 };
115 #endif
116 
117 static struct procabi_table abis[] = {
118 #if __SIZEOF_POINTER__ == 4
119 	{ "FreeBSD ELF32", &freebsd },
120 #elif __SIZEOF_POINTER__ == 8
121 	{ "FreeBSD ELF64", &freebsd },
122 	{ "FreeBSD ELF32", &freebsd32 },
123 #else
124 #error "Unsupported pointer size"
125 #endif
126 #if defined(__powerpc64__)
127 	{ "FreeBSD ELF64 V2", &freebsd },
128 #endif
129 #if defined(__amd64__)
130 	{ "FreeBSD a.out", &freebsd32 },
131 #endif
132 #if defined(__i386__)
133 	{ "FreeBSD a.out", &freebsd },
134 #endif
135 #if __SIZEOF_POINTER__ >= 8
136 	{ "Linux ELF64", &linux },
137 	{ "Linux ELF32", &linux32 },
138 #else
139 	{ "Linux ELF32", &linux },
140 #endif
141 };
142 
143 /*
144  * setup_and_wait() is called to start a process.  All it really does
145  * is fork(), enable tracing in the child, and then exec the given
146  * command.  At that point, the child process stops, and the parent
147  * can wake up and deal with it.
148  */
149 void
150 setup_and_wait(struct trussinfo *info, char *command[])
151 {
152 	pid_t pid;
153 
154 	pid = vfork();
155 	if (pid == -1)
156 		err(1, "fork failed");
157 	if (pid == 0) {	/* Child */
158 		ptrace(PT_TRACE_ME, 0, 0, 0);
159 		execvp(command[0], command);
160 		err(1, "execvp %s", command[0]);
161 	}
162 
163 	/* Only in the parent here */
164 	if (waitpid(pid, NULL, 0) < 0)
165 		err(1, "unexpect stop in waitpid");
166 
167 	new_proc(info, pid, 0);
168 }
169 
170 /*
171  * start_tracing is called to attach to an existing process.
172  */
173 void
174 start_tracing(struct trussinfo *info, pid_t pid)
175 {
176 	int ret, retry;
177 
178 	retry = 10;
179 	do {
180 		ret = ptrace(PT_ATTACH, pid, NULL, 0);
181 		usleep(200);
182 	} while (ret && retry-- > 0);
183 	if (ret)
184 		err(1, "can not attach to target process");
185 
186 	if (waitpid(pid, NULL, 0) < 0)
187 		err(1, "Unexpect stop in waitpid");
188 
189 	new_proc(info, pid, 0);
190 }
191 
192 /*
193  * Restore a process back to it's pre-truss state.
194  * Called for SIGINT, SIGTERM, SIGQUIT.  This only
195  * applies if truss was told to monitor an already-existing
196  * process.
197  */
198 void
199 restore_proc(int signo __unused)
200 {
201 
202 	detaching = 1;
203 }
204 
205 static void
206 detach_proc(pid_t pid)
207 {
208 	int sig, status;
209 
210 	/*
211 	 * Stop the child so that we can detach.  Filter out possible
212 	 * lingering SIGTRAP events buffered in the threads.
213 	 */
214 	kill(pid, SIGSTOP);
215 	for (;;) {
216 		if (waitpid(pid, &status, 0) < 0)
217 			err(1, "Unexpected error in waitpid");
218 		sig = WIFSTOPPED(status) ? WSTOPSIG(status) : 0;
219 		if (sig == SIGSTOP)
220 			break;
221 		if (sig == SIGTRAP)
222 			sig = 0;
223 		if (ptrace(PT_CONTINUE, pid, (caddr_t)1, sig) < 0)
224 			err(1, "Can not continue for detach");
225 	}
226 
227 	if (ptrace(PT_DETACH, pid, (caddr_t)1, 0) < 0)
228 		err(1, "Can not detach the process");
229 
230 	kill(pid, SIGCONT);
231 }
232 
233 /*
234  * Determine the ABI.  This is called after every exec, and when
235  * a process is first monitored.
236  */
237 static struct procabi *
238 find_abi(pid_t pid)
239 {
240 	size_t len;
241 	unsigned int i;
242 	int error;
243 	int mib[4];
244 	char progt[32];
245 
246 	len = sizeof(progt);
247 	mib[0] = CTL_KERN;
248 	mib[1] = KERN_PROC;
249 	mib[2] = KERN_PROC_SV_NAME;
250 	mib[3] = pid;
251 	error = sysctl(mib, 4, progt, &len, NULL, 0);
252 	if (error != 0)
253 		err(2, "can not get sysvec name");
254 
255 	for (i = 0; i < nitems(abis); i++) {
256 		if (strcmp(abis[i].name, progt) == 0)
257 			return (abis[i].abi);
258 	}
259 	warnx("ABI %s for pid %ld is not supported", progt, (long)pid);
260 	return (NULL);
261 }
262 
263 static struct threadinfo *
264 new_thread(struct procinfo *p, lwpid_t lwpid)
265 {
266 	struct threadinfo *nt;
267 
268 	/*
269 	 * If this happens it means there is a bug in truss.  Unfortunately
270 	 * this will kill any processes truss is attached to.
271 	 */
272 	LIST_FOREACH(nt, &p->threadlist, entries) {
273 		if (nt->tid == lwpid)
274 			errx(1, "Duplicate thread for LWP %ld", (long)lwpid);
275 	}
276 
277 	nt = calloc(1, sizeof(struct threadinfo));
278 	if (nt == NULL)
279 		err(1, "calloc() failed");
280 	nt->proc = p;
281 	nt->tid = lwpid;
282 	LIST_INSERT_HEAD(&p->threadlist, nt, entries);
283 	return (nt);
284 }
285 
286 static void
287 free_thread(struct threadinfo *t)
288 {
289 
290 	LIST_REMOVE(t, entries);
291 	free(t);
292 }
293 
294 static void
295 add_threads(struct trussinfo *info, struct procinfo *p)
296 {
297 	struct ptrace_lwpinfo pl;
298 	struct threadinfo *t;
299 	lwpid_t *lwps;
300 	int i, nlwps;
301 
302 	nlwps = ptrace(PT_GETNUMLWPS, p->pid, NULL, 0);
303 	if (nlwps == -1)
304 		err(1, "Unable to fetch number of LWPs");
305 	assert(nlwps > 0);
306 	lwps = calloc(nlwps, sizeof(*lwps));
307 	nlwps = ptrace(PT_GETLWPLIST, p->pid, (caddr_t)lwps, nlwps);
308 	if (nlwps == -1)
309 		err(1, "Unable to fetch LWP list");
310 	for (i = 0; i < nlwps; i++) {
311 		t = new_thread(p, lwps[i]);
312 		if (ptrace(PT_LWPINFO, lwps[i], (caddr_t)&pl, sizeof(pl)) == -1)
313 			err(1, "ptrace(PT_LWPINFO)");
314 		if (pl.pl_flags & PL_FLAG_SCE) {
315 			info->curthread = t;
316 			enter_syscall(info, t, &pl);
317 		}
318 	}
319 	free(lwps);
320 }
321 
322 static void
323 new_proc(struct trussinfo *info, pid_t pid, lwpid_t lwpid)
324 {
325 	struct procinfo *np;
326 
327 	/*
328 	 * If this happens it means there is a bug in truss.  Unfortunately
329 	 * this will kill any processes truss is attached to.
330 	 */
331 	LIST_FOREACH(np, &info->proclist, entries) {
332 		if (np->pid == pid)
333 			errx(1, "Duplicate process for pid %ld", (long)pid);
334 	}
335 
336 	if (info->flags & FOLLOWFORKS)
337 		if (ptrace(PT_FOLLOW_FORK, pid, NULL, 1) == -1)
338 			err(1, "Unable to follow forks for pid %ld", (long)pid);
339 	if (ptrace(PT_LWP_EVENTS, pid, NULL, 1) == -1)
340 		err(1, "Unable to enable LWP events for pid %ld", (long)pid);
341 	np = calloc(1, sizeof(struct procinfo));
342 	np->pid = pid;
343 	np->abi = find_abi(pid);
344 	LIST_INIT(&np->threadlist);
345 	LIST_INSERT_HEAD(&info->proclist, np, entries);
346 
347 	if (lwpid != 0)
348 		new_thread(np, lwpid);
349 	else
350 		add_threads(info, np);
351 }
352 
353 static void
354 free_proc(struct procinfo *p)
355 {
356 	struct threadinfo *t, *t2;
357 
358 	LIST_FOREACH_SAFE(t, &p->threadlist, entries, t2) {
359 		free(t);
360 	}
361 	LIST_REMOVE(p, entries);
362 	free(p);
363 }
364 
365 static void
366 detach_all_procs(struct trussinfo *info)
367 {
368 	struct procinfo *p, *p2;
369 
370 	LIST_FOREACH_SAFE(p, &info->proclist, entries, p2) {
371 		detach_proc(p->pid);
372 		free_proc(p);
373 	}
374 }
375 
376 static struct procinfo *
377 find_proc(struct trussinfo *info, pid_t pid)
378 {
379 	struct procinfo *np;
380 
381 	LIST_FOREACH(np, &info->proclist, entries) {
382 		if (np->pid == pid)
383 			return (np);
384 	}
385 
386 	return (NULL);
387 }
388 
389 /*
390  * Change curthread member based on (pid, lwpid).
391  */
392 static void
393 find_thread(struct trussinfo *info, pid_t pid, lwpid_t lwpid)
394 {
395 	struct procinfo *np;
396 	struct threadinfo *nt;
397 
398 	np = find_proc(info, pid);
399 	assert(np != NULL);
400 
401 	LIST_FOREACH(nt, &np->threadlist, entries) {
402 		if (nt->tid == lwpid) {
403 			info->curthread = nt;
404 			return;
405 		}
406 	}
407 	errx(1, "could not find thread");
408 }
409 
410 /*
411  * When a process exits, it should have exactly one thread left.
412  * All of the other threads should have reported thread exit events.
413  */
414 static void
415 find_exit_thread(struct trussinfo *info, pid_t pid)
416 {
417 	struct procinfo *p;
418 
419 	p = find_proc(info, pid);
420 	assert(p != NULL);
421 
422 	info->curthread = LIST_FIRST(&p->threadlist);
423 	assert(info->curthread != NULL);
424 	assert(LIST_NEXT(info->curthread, entries) == NULL);
425 }
426 
427 static void
428 alloc_syscall(struct threadinfo *t, struct ptrace_lwpinfo *pl)
429 {
430 	u_int i;
431 
432 	assert(t->in_syscall == 0);
433 	assert(t->cs.number == 0);
434 	assert(t->cs.sc == NULL);
435 	assert(t->cs.nargs == 0);
436 	for (i = 0; i < nitems(t->cs.s_args); i++)
437 		assert(t->cs.s_args[i] == NULL);
438 	memset(t->cs.args, 0, sizeof(t->cs.args));
439 	t->cs.number = pl->pl_syscall_code;
440 	t->in_syscall = 1;
441 }
442 
443 static void
444 free_syscall(struct threadinfo *t)
445 {
446 	u_int i;
447 
448 	for (i = 0; i < t->cs.nargs; i++)
449 		free(t->cs.s_args[i]);
450 	memset(&t->cs, 0, sizeof(t->cs));
451 	t->in_syscall = 0;
452 }
453 
454 static void
455 enter_syscall(struct trussinfo *info, struct threadinfo *t,
456     struct ptrace_lwpinfo *pl)
457 {
458 	struct syscall *sc;
459 	u_int i, narg;
460 
461 	alloc_syscall(t, pl);
462 	narg = MIN(pl->pl_syscall_narg, nitems(t->cs.args));
463 	if (narg != 0 && ptrace(PT_GET_SC_ARGS, t->tid, (caddr_t)t->cs.args,
464 	    sizeof(t->cs.args)) != 0) {
465 		free_syscall(t);
466 		return;
467 	}
468 
469 	sc = get_syscall(t, t->cs.number, narg);
470 	if (sc->unknown)
471 		fprintf(info->outfile, "-- UNKNOWN %s SYSCALL %d --\n",
472 		    t->proc->abi->type, t->cs.number);
473 
474 	t->cs.nargs = sc->decode.nargs;
475 	assert(sc->decode.nargs <= nitems(t->cs.s_args));
476 
477 	t->cs.sc = sc;
478 
479 	/*
480 	 * At this point, we set up the system call arguments.
481 	 * We ignore any OUT ones, however -- those are arguments that
482 	 * are set by the system call, and so are probably meaningless
483 	 * now.	This doesn't currently support arguments that are
484 	 * passed in *and* out, however.
485 	 */
486 #if DEBUG
487 	fprintf(stderr, "syscall %s(", sc->name);
488 #endif
489 	for (i = 0; i < t->cs.nargs; i++) {
490 #if DEBUG
491 		fprintf(stderr, "0x%lx%s",
492 		    t->cs.args[sc->decode.args[i].offset],
493 		    i < (t->cs.nargs - 1) ? "," : "");
494 #endif
495 		if (!(sc->decode.args[i].type & OUT)) {
496 			t->cs.s_args[i] = print_arg(&sc->decode.args[i],
497 			    t->cs.args, NULL, info);
498 		}
499 	}
500 #if DEBUG
501 	fprintf(stderr, ")\n");
502 #endif
503 
504 	clock_gettime(CLOCK_REALTIME, &t->before);
505 }
506 
507 /*
508  * When a thread exits voluntarily (including when a thread calls
509  * exit() to trigger a process exit), the thread's internal state
510  * holds the arguments passed to the exit system call.  When the
511  * thread's exit is reported, log that system call without a return
512  * value.
513  */
514 static void
515 thread_exit_syscall(struct trussinfo *info)
516 {
517 	struct threadinfo *t;
518 
519 	t = info->curthread;
520 	if (!t->in_syscall)
521 		return;
522 
523 	clock_gettime(CLOCK_REALTIME, &t->after);
524 
525 	print_syscall_ret(info, 0, NULL);
526 	free_syscall(t);
527 }
528 
529 static void
530 exit_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
531 {
532 	struct threadinfo *t;
533 	struct procinfo *p;
534 	struct syscall *sc;
535 	struct ptrace_sc_ret psr;
536 	u_int i;
537 
538 	t = info->curthread;
539 	if (!t->in_syscall)
540 		return;
541 
542 	clock_gettime(CLOCK_REALTIME, &t->after);
543 	p = t->proc;
544 	if (ptrace(PT_GET_SC_RET, t->tid, (caddr_t)&psr, sizeof(psr)) != 0) {
545 		free_syscall(t);
546 		return;
547 	}
548 
549 	sc = t->cs.sc;
550 	/*
551 	 * Here, we only look for arguments that have OUT masked in --
552 	 * otherwise, they were handled in enter_syscall().
553 	 */
554 	for (i = 0; i < sc->decode.nargs; i++) {
555 		char *temp;
556 
557 		if (sc->decode.args[i].type & OUT) {
558 			/*
559 			 * If an error occurred, then don't bother
560 			 * getting the data; it may not be valid.
561 			 */
562 			if (psr.sr_error != 0) {
563 				asprintf(&temp, "0x%lx",
564 				    (long)t->cs.args[sc->decode.args[i].offset]);
565 			} else {
566 				temp = print_arg(&sc->decode.args[i],
567 				    t->cs.args, psr.sr_retval, info);
568 			}
569 			t->cs.s_args[i] = temp;
570 		}
571 	}
572 
573 	print_syscall_ret(info, psr.sr_error, psr.sr_retval);
574 	free_syscall(t);
575 
576 	/*
577 	 * If the process executed a new image, check the ABI.  If the
578 	 * new ABI isn't supported, stop tracing this process.
579 	 */
580 	if (pl->pl_flags & PL_FLAG_EXEC) {
581 		assert(LIST_NEXT(LIST_FIRST(&p->threadlist), entries) == NULL);
582 		p->abi = find_abi(p->pid);
583 		if (p->abi == NULL) {
584 			if (ptrace(PT_DETACH, p->pid, (caddr_t)1, 0) < 0)
585 				err(1, "Can not detach the process");
586 			free_proc(p);
587 		}
588 	}
589 }
590 
591 int
592 print_line_prefix(struct trussinfo *info)
593 {
594 	struct timespec timediff;
595 	struct threadinfo *t;
596 	int len;
597 
598 	len = 0;
599 	t = info->curthread;
600 	if (info->flags & (FOLLOWFORKS | DISPLAYTIDS)) {
601 		if (info->flags & FOLLOWFORKS)
602 			len += fprintf(info->outfile, "%5d", t->proc->pid);
603 		if ((info->flags & (FOLLOWFORKS | DISPLAYTIDS)) ==
604 		    (FOLLOWFORKS | DISPLAYTIDS))
605 			len += fprintf(info->outfile, " ");
606 		if (info->flags & DISPLAYTIDS)
607 			len += fprintf(info->outfile, "%6d", t->tid);
608 		len += fprintf(info->outfile, ": ");
609 	}
610 	if (info->flags & ABSOLUTETIMESTAMPS) {
611 		timespecsub(&t->after, &info->start_time, &timediff);
612 		len += fprintf(info->outfile, "%jd.%09ld ",
613 		    (intmax_t)timediff.tv_sec, timediff.tv_nsec);
614 	}
615 	if (info->flags & RELATIVETIMESTAMPS) {
616 		timespecsub(&t->after, &t->before, &timediff);
617 		len += fprintf(info->outfile, "%jd.%09ld ",
618 		    (intmax_t)timediff.tv_sec, timediff.tv_nsec);
619 	}
620 	return (len);
621 }
622 
623 static void
624 report_thread_death(struct trussinfo *info)
625 {
626 	struct threadinfo *t;
627 
628 	t = info->curthread;
629 	clock_gettime(CLOCK_REALTIME, &t->after);
630 	print_line_prefix(info);
631 	fprintf(info->outfile, "<thread %ld exited>\n", (long)t->tid);
632 }
633 
634 static void
635 report_thread_birth(struct trussinfo *info)
636 {
637 	struct threadinfo *t;
638 
639 	t = info->curthread;
640 	clock_gettime(CLOCK_REALTIME, &t->after);
641 	t->before = t->after;
642 	print_line_prefix(info);
643 	fprintf(info->outfile, "<new thread %ld>\n", (long)t->tid);
644 }
645 
646 static void
647 report_exit(struct trussinfo *info, siginfo_t *si)
648 {
649 	struct threadinfo *t;
650 
651 	t = info->curthread;
652 	clock_gettime(CLOCK_REALTIME, &t->after);
653 	print_line_prefix(info);
654 	if (si->si_code == CLD_EXITED)
655 		fprintf(info->outfile, "process exit, rval = %u\n",
656 		    si->si_status);
657 	else
658 		fprintf(info->outfile, "process killed, signal = %u%s\n",
659 		    si->si_status, si->si_code == CLD_DUMPED ?
660 		    " (core dumped)" : "");
661 }
662 
663 static void
664 report_new_child(struct trussinfo *info)
665 {
666 	struct threadinfo *t;
667 
668 	t = info->curthread;
669 	clock_gettime(CLOCK_REALTIME, &t->after);
670 	t->before = t->after;
671 	print_line_prefix(info);
672 	fprintf(info->outfile, "<new process>\n");
673 }
674 
675 void
676 decode_siginfo(FILE *fp, siginfo_t *si)
677 {
678 	const char *str;
679 
680 	fprintf(fp, " code=");
681 	str = sysdecode_sigcode(si->si_signo, si->si_code);
682 	if (str == NULL)
683 		fprintf(fp, "%d", si->si_code);
684 	else
685 		fprintf(fp, "%s", str);
686 	switch (si->si_code) {
687 	case SI_NOINFO:
688 		break;
689 	case SI_QUEUE:
690 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
691 		/* FALLTHROUGH */
692 	case SI_USER:
693 	case SI_LWP:
694 		fprintf(fp, " pid=%jd uid=%jd", (intmax_t)si->si_pid,
695 		    (intmax_t)si->si_uid);
696 		break;
697 	case SI_TIMER:
698 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
699 		fprintf(fp, " timerid=%d", si->si_timerid);
700 		fprintf(fp, " overrun=%d", si->si_overrun);
701 		if (si->si_errno != 0)
702 			fprintf(fp, " errno=%d", si->si_errno);
703 		break;
704 	case SI_ASYNCIO:
705 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
706 		break;
707 	case SI_MESGQ:
708 		fprintf(fp, " value=%p", si->si_value.sival_ptr);
709 		fprintf(fp, " mqd=%d", si->si_mqd);
710 		break;
711 	default:
712 		switch (si->si_signo) {
713 		case SIGILL:
714 		case SIGFPE:
715 		case SIGSEGV:
716 		case SIGBUS:
717 			fprintf(fp, " trapno=%d", si->si_trapno);
718 			fprintf(fp, " addr=%p", si->si_addr);
719 			break;
720 		case SIGCHLD:
721 			fprintf(fp, " pid=%jd uid=%jd", (intmax_t)si->si_pid,
722 			    (intmax_t)si->si_uid);
723 			fprintf(fp, " status=%d", si->si_status);
724 			break;
725 		}
726 	}
727 }
728 
729 static void
730 report_signal(struct trussinfo *info, siginfo_t *si, struct ptrace_lwpinfo *pl)
731 {
732 	struct threadinfo *t;
733 	const char *signame;
734 
735 	t = info->curthread;
736 	clock_gettime(CLOCK_REALTIME, &t->after);
737 	print_line_prefix(info);
738 	signame = sysdecode_signal(si->si_status);
739 	if (signame == NULL)
740 		signame = "?";
741 	fprintf(info->outfile, "SIGNAL %u (%s)", si->si_status, signame);
742 	if (pl->pl_event == PL_EVENT_SIGNAL && pl->pl_flags & PL_FLAG_SI)
743 		decode_siginfo(info->outfile, &pl->pl_siginfo);
744 	fprintf(info->outfile, "\n");
745 
746 }
747 
748 /*
749  * Wait for events until all the processes have exited or truss has been
750  * asked to stop.
751  */
752 void
753 eventloop(struct trussinfo *info)
754 {
755 	struct ptrace_lwpinfo pl;
756 	siginfo_t si;
757 	int pending_signal;
758 
759 	while (!LIST_EMPTY(&info->proclist)) {
760 		if (detaching) {
761 			detach_all_procs(info);
762 			return;
763 		}
764 
765 		if (waitid(P_ALL, 0, &si, WTRAPPED | WEXITED) == -1) {
766 			if (errno == EINTR)
767 				continue;
768 			err(1, "Unexpected error from waitid");
769 		}
770 
771 		assert(si.si_signo == SIGCHLD);
772 
773 		switch (si.si_code) {
774 		case CLD_EXITED:
775 		case CLD_KILLED:
776 		case CLD_DUMPED:
777 			find_exit_thread(info, si.si_pid);
778 			if ((info->flags & COUNTONLY) == 0) {
779 				if (si.si_code == CLD_EXITED)
780 					thread_exit_syscall(info);
781 				report_exit(info, &si);
782 			}
783 			free_proc(info->curthread->proc);
784 			info->curthread = NULL;
785 			break;
786 		case CLD_TRAPPED:
787 			if (ptrace(PT_LWPINFO, si.si_pid, (caddr_t)&pl,
788 			    sizeof(pl)) == -1)
789 				err(1, "ptrace(PT_LWPINFO)");
790 
791 			if (pl.pl_flags & PL_FLAG_CHILD) {
792 				new_proc(info, si.si_pid, pl.pl_lwpid);
793 				assert(LIST_FIRST(&info->proclist)->abi !=
794 				    NULL);
795 			} else if (pl.pl_flags & PL_FLAG_BORN)
796 				new_thread(find_proc(info, si.si_pid),
797 				    pl.pl_lwpid);
798 			find_thread(info, si.si_pid, pl.pl_lwpid);
799 
800 			if (si.si_status == SIGTRAP &&
801 			    (pl.pl_flags & (PL_FLAG_BORN|PL_FLAG_EXITED|
802 			    PL_FLAG_SCE|PL_FLAG_SCX)) != 0) {
803 				if (pl.pl_flags & PL_FLAG_BORN) {
804 					if ((info->flags & COUNTONLY) == 0)
805 						report_thread_birth(info);
806 				} else if (pl.pl_flags & PL_FLAG_EXITED) {
807 					if ((info->flags & COUNTONLY) == 0)
808 						report_thread_death(info);
809 					free_thread(info->curthread);
810 					info->curthread = NULL;
811 				} else if (pl.pl_flags & PL_FLAG_SCE)
812 					enter_syscall(info, info->curthread, &pl);
813 				else if (pl.pl_flags & PL_FLAG_SCX)
814 					exit_syscall(info, &pl);
815 				pending_signal = 0;
816 			} else if (pl.pl_flags & PL_FLAG_CHILD) {
817 				if ((info->flags & COUNTONLY) == 0)
818 					report_new_child(info);
819 				pending_signal = 0;
820 			} else {
821 				if ((info->flags & NOSIGS) == 0)
822 					report_signal(info, &si, &pl);
823 				pending_signal = si.si_status;
824 			}
825 			ptrace(PT_SYSCALL, si.si_pid, (caddr_t)1,
826 			    pending_signal);
827 			break;
828 		case CLD_STOPPED:
829 			errx(1, "waitid reported CLD_STOPPED");
830 		case CLD_CONTINUED:
831 			break;
832 		}
833 	}
834 }
835