strace.c revision 16a03d2e97415afe6cf34172a0aea97a95a0b160 
1/*
2 * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
3 * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
4 * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
5 * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
6 * 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. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 *	$Id$
31 */
32
33#include <sys/types.h>
34#include "defs.h"
35
36#include <signal.h>
37#include <errno.h>
38#include <sys/param.h>
39#include <fcntl.h>
40#include <sys/resource.h>
41#include <sys/wait.h>
42#include <sys/stat.h>
43#include <pwd.h>
44#include <grp.h>
45#include <string.h>
46
47#ifdef SVR4
48#include <sys/stropts.h>
49#include <poll.h>
50#ifdef HAVE_MP_PROCFS
51#include <sys/uio.h>
52#endif
53#endif
54
55int debug = 0, followfork = 0, followvfork = 0, interactive = 0;
56int rflag = 0, tflag = 0, dtime = 0, cflag = 0;
57int iflag = 0, xflag = 0, qflag = 0;
58int pflag_seen = 0;
59
60char *username = NULL;
61uid_t run_uid;
62gid_t run_gid;
63
64int acolumn = DEFAULT_ACOLUMN;
65int max_strlen = DEFAULT_STRLEN;
66char *outfname = NULL;
67FILE *outf;
68struct tcb tcbtab[MAX_PROCS];
69int nprocs;
70char *progname;
71extern char version[];
72extern char **environ;
73
74static struct tcb *pid2tcb P((int pid));
75static int trace P((void));
76static void cleanup P((void));
77static void interrupt P((int sig));
78static sigset_t empty_set, blocked_set;
79
80#ifdef HAVE_SIG_ATOMIC_T
81static volatile sig_atomic_t interrupted;
82#else /* !HAVE_SIG_ATOMIC_T */
83#ifdef __STDC__
84static volatile int interrupted;
85#else /* !__STDC__ */
86static int interrupted;
87#endif /* !__STDC__ */
88#endif /* !HAVE_SIG_ATOMIC_T */
89
90#ifdef SVR4
91
92static struct tcb *pfd2tcb P((int pfd));
93static void reaper P((int sig));
94static void rebuild_pollv P((void));
95struct pollfd pollv[MAX_PROCS];
96
97#ifndef HAVE_POLLABLE_PROCFS
98
99static void proc_poll_open P((void));
100static void proc_poller P((int pfd));
101
102struct proc_pollfd {
103	int fd;
104	int revents;
105	int pid;
106};
107
108static int poller_pid;
109static int proc_poll_pipe[2] = { -1, -1 };
110
111#endif /* !HAVE_POLLABLE_PROCFS */
112
113#ifdef HAVE_MP_PROCFS
114#define POLLWANT	POLLWRNORM
115#else
116#define POLLWANT	POLLPRI
117#endif
118#endif /* SVR4 */
119
120static void
121usage(ofp, exitval)
122FILE *ofp;
123int exitval;
124{
125	fprintf(ofp, "\
126usage: strace [-dffhiqrtttTvVxx] [-a column] [-e expr] ... [-o file]\n\
127              [-p pid] ... [-s strsize] [-u username] [command [arg ...]]\n\
128   or: strace -c [-e expr] ... [-O overhead] [-S sortby] [command [arg ...]]\n\
129-c -- count time, calls, and errors for each syscall and report summary\n\
130-f -- follow forks, -ff -- with output into separate files\n\
131-F -- attempt to follow vforks, -h -- print help message\n\
132-i -- print instruction pointer at time of syscall\n\
133-q -- suppress messages about attaching, detaching, etc.\n\
134-r -- print relative timestamp, -t -- absolute timestamp, -tt -- with usecs\n\
135-T -- print time spent in each syscall, -V -- print version\n\
136-v -- verbose mode: print unabbreviated argv, stat, termio[s], etc. args\n\
137-x -- print non-ascii strings in hex, -xx -- print all strings in hex\n\
138-a column -- alignment COLUMN for printing syscall results (default %d)\n\
139-e expr -- a qualifying expression: option=[!]all or option=[!]val1[,val2]...\n\
140   options: trace, abbrev, verbose, raw, signal, read, or write\n\
141-o file -- send trace output to FILE instead of stderr\n\
142-O overhead -- set overhead for tracing syscalls to OVERHEAD usecs\n\
143-p pid -- trace process with process id PID, may be repeated\n\
144-s strsize -- limit length of print strings to STRSIZE chars (default %d)\n\
145-S sortby -- sort syscall counts by: time, calls, name, nothing (default %s)\n\
146-u username -- run command as username handling setuid and/or setgid\n\
147", DEFAULT_ACOLUMN, DEFAULT_STRLEN, DEFAULT_SORTBY);
148	exit(exitval);
149}
150
151#ifdef SVR4
152#ifdef MIPS
153void
154foobar()
155{
156}
157#endif /* MIPS */
158#endif /* SVR4 */
159
160int
161main(argc, argv)
162int argc;
163char *argv[];
164{
165	extern int optind;
166	extern char *optarg;
167	struct tcb *tcp;
168	int c, pid = 0;
169	struct sigaction sa;
170
171	static char buf[BUFSIZ];
172
173	progname = argv[0];
174	outf = stderr;
175	interactive = 1;
176	qualify("trace=all");
177	qualify("abbrev=all");
178	qualify("verbose=all");
179	qualify("signal=all");
180	set_sortby(DEFAULT_SORTBY);
181	set_personality(DEFAULT_PERSONALITY);
182	while ((c = getopt(argc, argv,
183		"+cdfFhiqrtTvVxa:e:o:O:p:s:S:u:")) != EOF) {
184		switch (c) {
185		case 'c':
186			cflag++;
187			dtime++;
188			break;
189		case 'd':
190			debug++;
191			break;
192		case 'f':
193			followfork++;
194			break;
195		case 'F':
196			followvfork++;
197			break;
198		case 'h':
199			usage(stdout, 0);
200			break;
201		case 'i':
202			iflag++;
203			break;
204		case 'q':
205			qflag++;
206			break;
207		case 'r':
208			rflag++;
209			tflag++;
210			break;
211		case 't':
212			tflag++;
213			break;
214		case 'T':
215			dtime++;
216			break;
217		case 'x':
218			xflag++;
219			break;
220		case 'v':
221			qualify("abbrev=none");
222			break;
223		case 'V':
224			printf("%s\n", version);
225			exit(0);
226			break;
227		case 'a':
228			acolumn = atoi(optarg);
229			break;
230		case 'e':
231			qualify(optarg);
232			break;
233		case 'o':
234			outfname = strdup(optarg);
235			break;
236		case 'O':
237			set_overhead(atoi(optarg));
238			break;
239		case 'p':
240			if ((pid = atoi(optarg)) == 0) {
241				fprintf(stderr, "%s: Invalid process id: %s\n",
242					progname, optarg);
243				break;
244			}
245			if (pid == getpid()) {
246				fprintf(stderr, "%s: I'm sorry, I can't let you do that, Dave.\n", progname);
247				break;
248			}
249			if ((tcp = alloctcb(pid)) == NULL) {
250				fprintf(stderr, "%s: tcb table full, please recompile strace\n",
251					progname);
252				exit(1);
253			}
254			tcp->flags |= TCB_ATTACHED;
255			pflag_seen++;
256			break;
257		case 's':
258			max_strlen = atoi(optarg);
259			break;
260		case 'S':
261			set_sortby(optarg);
262			break;
263		case 'u':
264			username = strdup(optarg);
265			break;
266		default:
267			usage(stderr, 1);
268			break;
269		}
270	}
271
272	/* See if they want to run as another user. */
273	if (username != NULL) {
274		struct passwd *pent;
275
276		if (getuid() != 0 || geteuid() != 0) {
277			fprintf(stderr,
278				"%s: you must be root to use the -u option\n",
279				progname);
280			exit(1);
281		}
282		if ((pent = getpwnam(username)) == NULL) {
283			fprintf(stderr, "%s: cannot find user `%s'\n",
284				progname, optarg);
285			exit(1);
286		}
287		run_uid = pent->pw_uid;
288		run_gid = pent->pw_gid;
289	}
290	else {
291		run_uid = getuid();
292		run_gid = getgid();
293	}
294
295#ifndef SVR4
296	setreuid(geteuid(), getuid());
297#endif
298
299	/* See if they want to pipe the output. */
300	if (outfname && (outfname[0] == '|' || outfname[0] == '!')) {
301		if ((outf = popen(outfname + 1, "w")) == NULL) {
302			fprintf(stderr, "%s: can't popen '%s': %s\n",
303				progname, outfname + 1, strerror(errno));
304			exit(1);
305		}
306		free(outfname);
307		outfname = NULL;
308	}
309
310	/* Check if they want to redirect the output. */
311	if (outfname) {
312		if ((outf = fopen(outfname, "w")) == NULL) {
313			fprintf(stderr, "%s: can't fopen '%s': %s\n",
314				progname, outfname, strerror(errno));
315			exit(1);
316		}
317	}
318
319#ifndef SVR4
320	setreuid(geteuid(), getuid());
321#endif
322
323	if (!outfname) {
324		qflag = 1;
325		setvbuf(outf, buf, _IOLBF, BUFSIZ);
326	}
327	else if (optind < argc)
328		interactive = 0;
329	else
330		qflag = 1;
331
332	for (c = 0, tcp = tcbtab; c < MAX_PROCS; c++, tcp++) {
333		/* Reinitialize the output since it may have changed. */
334		tcp->outf = outf;
335		if (!(tcp->flags & TCB_INUSE) || !(tcp->flags & TCB_ATTACHED))
336			continue;
337#ifdef SVR4
338		if (proc_open(tcp, 1) < 0) {
339			fprintf(stderr, "trouble opening proc file\n");
340			droptcb(tcp);
341			continue;
342		}
343#else /* !SVR4 */
344		if (ptrace(PTRACE_ATTACH, tcp->pid, (char *) 1, 0) < 0) {
345			perror("attach: ptrace(PTRACE_ATTACH, ...)");
346			droptcb(tcp);
347			continue;
348		}
349#endif /* !SVR4 */
350		if (!qflag)
351			fprintf(stderr,
352				"Process %u attached - interrupt to quit\n",
353				pid);
354	}
355
356	if (optind < argc) {
357		struct stat statbuf;
358		char *filename;
359		char pathname[MAXPATHLEN];
360
361		filename = argv[optind];
362		if (strchr(filename, '/'))
363			strcpy(pathname, filename);
364#ifdef USE_DEBUGGING_EXEC
365		/*
366		 * Debuggers customarily check the current directory
367		 * first regardless of the path but doing that gives
368		 * security geeks a panic attack.
369		 */
370		else if (stat(filename, &statbuf) == 0)
371			strcpy(pathname, filename);
372#endif /* USE_DEBUGGING_EXEC */
373		else {
374			char *path;
375			int m, n, len;
376
377			for (path = getenv("PATH"); path && *path; path += m) {
378				if (strchr(path, ':')) {
379					n = strchr(path, ':') - path;
380					m = n + 1;
381				}
382				else
383					m = n = strlen(path);
384				if (n == 0) {
385					getcwd(pathname, MAXPATHLEN);
386					len = strlen(pathname);
387				}
388				else {
389					strncpy(pathname, path, n);
390					len = n;
391				}
392				if (len && pathname[len - 1] != '/')
393					pathname[len++] = '/';
394				strcpy(pathname + len, filename);
395				if (stat(pathname, &statbuf) == 0)
396					break;
397			}
398		}
399		if (stat(pathname, &statbuf) < 0) {
400			fprintf(stderr, "%s: %s: command not found\n",
401				progname, filename);
402			exit(1);
403		}
404		switch (pid = fork()) {
405		case -1:
406			perror("strace: fork");
407			cleanup();
408			exit(1);
409			break;
410		case 0: {
411#ifdef SVR4
412			if (outf != stderr) close (fileno (outf));
413#ifdef MIPS
414			/* Kludge for SGI, see proc_open for details. */
415			sa.sa_handler = foobar;
416			sa.sa_flags = 0;
417			sigemptyset(&sa.sa_mask);
418			sigaction(SIGINT, &sa, NULL);
419#endif /* MIPS */
420			pause();
421#else /* !SVR4 */
422			if (outf!=stderr)
423				close(fileno (outf));
424
425			if (ptrace(PTRACE_TRACEME, 0, (char *) 1, 0) < 0) {
426				perror("strace: ptrace(PTRACE_TRACEME, ...)");
427				return -1;
428			}
429			if (debug)
430				kill(getpid(), SIGSTOP);
431
432			if (username != NULL || geteuid() == 0) {
433				uid_t run_euid = run_uid;
434				gid_t run_egid = run_gid;
435
436				if (statbuf.st_mode & S_ISUID)
437					run_euid = statbuf.st_uid;
438				if (statbuf.st_mode & S_ISGID)
439					run_egid = statbuf.st_gid;
440
441				/*
442				 * It is important to set groups before we
443				 * lose privileges on setuid.
444				 */
445				if (username != NULL) {
446					if (initgroups(username, run_gid) < 0) {
447						perror("initgroups");
448						exit(1);
449					}
450					if (setregid(run_gid, run_egid) < 0) {
451						perror("setregid");
452						exit(1);
453					}
454					if (setreuid(run_uid, run_euid) < 0) {
455						perror("setreuid");
456						exit(1);
457					}
458				}
459			}
460			else
461				setreuid(run_uid, run_uid);
462#endif /* !SVR4 */
463
464			execv(pathname, &argv[optind]);
465			perror("strace: exec");
466			_exit(1);
467			break;
468		}
469		default:
470			if ((tcp = alloctcb(pid)) == NULL) {
471				fprintf(stderr, "tcb table full\n");
472				cleanup();
473				exit(1);
474			}
475#ifdef SVR4
476			if (proc_open(tcp, 0) < 0) {
477				fprintf(stderr, "trouble opening proc file\n");
478				cleanup();
479				exit(1);
480			}
481#endif /* SVR4 */
482#ifndef SVR4
483			fake_execve(tcp, pathname, &argv[optind], environ);
484#endif
485			break;
486		}
487	}
488	else if (pflag_seen == 0)
489		usage(stderr, 1);
490
491	sigemptyset(&empty_set);
492	sigemptyset(&blocked_set);
493	sa.sa_handler = SIG_IGN;
494	sigemptyset(&sa.sa_mask);
495	sa.sa_flags = 0;
496	sigaction(SIGTTOU, &sa, NULL);
497	sigaction(SIGTTIN, &sa, NULL);
498	if (interactive) {
499		sigaddset(&blocked_set, SIGHUP);
500		sigaddset(&blocked_set, SIGINT);
501		sigaddset(&blocked_set, SIGQUIT);
502		sigaddset(&blocked_set, SIGPIPE);
503		sigaddset(&blocked_set, SIGTERM);
504		sa.sa_handler = interrupt;
505#ifdef SUNOS4
506		/* POSIX signals on sunos4.1 are a little broken. */
507		sa.sa_flags = SA_INTERRUPT;
508#endif /* SUNOS4 */
509	}
510	sigaction(SIGHUP, &sa, NULL);
511	sigaction(SIGINT, &sa, NULL);
512	sigaction(SIGQUIT, &sa, NULL);
513	sigaction(SIGPIPE, &sa, NULL);
514	sigaction(SIGTERM, &sa, NULL);
515#ifdef SVR4
516	sa.sa_handler = reaper;
517	sigaction(SIGCHLD, &sa, NULL);
518#endif /* SVR4 */
519
520	if (trace() < 0)
521		exit(1);
522	cleanup();
523	exit(0);
524}
525
526void
527newoutf(tcp)
528struct tcb *tcp;
529{
530	char name[MAXPATHLEN];
531	FILE *fp;
532
533	if (outfname && followfork > 1) {
534		sprintf(name, "%s.%u", outfname, tcp->pid);
535#ifndef SVR4
536		setreuid(geteuid(), getuid());
537#endif
538		fp = fopen(name, "w");
539#ifndef SVR4
540		setreuid(geteuid(), getuid());
541#endif
542		if (fp == NULL) {
543			perror("fopen");
544			return;
545		}
546		tcp->outf = fp;
547	}
548	return;
549}
550
551struct tcb *
552alloctcb(pid)
553int pid;
554{
555	int i;
556	struct tcb *tcp;
557
558	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
559		if ((tcp->flags & TCB_INUSE) == 0) {
560			tcp->pid = pid;
561			tcp->parent = NULL;
562			tcp->nchildren = 0;
563			tcp->flags = TCB_INUSE | TCB_STARTUP;
564			tcp->outf = outf; /* Initialise to current out file */
565			tcp->stime.tv_sec = 0;
566			tcp->stime.tv_usec = 0;
567			tcp->pfd = -1;
568			nprocs++;
569			return tcp;
570		}
571	}
572	return NULL;
573}
574
575#ifdef SVR4
576int
577proc_open(tcp, attaching)
578struct tcb *tcp;
579int attaching;
580{
581	char proc[32];
582	long arg;
583	sysset_t sc_enter, sc_exit;
584	sigset_t signals;
585	fltset_t faults;
586#ifndef HAVE_POLLABLE_PROCFS
587	static int last_pfd;
588#endif
589
590#ifdef HAVE_MP_PROCFS
591	/* Open the process pseudo-files in /proc. */
592	sprintf(proc, "/proc/%d/ctl", tcp->pid);
593	if ((tcp->pfd = open(proc, O_WRONLY|O_EXCL)) < 0) {
594		perror("strace: open(\"/proc/...\", ...)");
595		return -1;
596	}
597	if ((arg = fcntl(tcp->pfd, F_GETFD)) < 0) {
598		perror("F_GETFD");
599		return -1;
600	}
601	if (fcntl(tcp->pfd, F_SETFD, arg|FD_CLOEXEC) < 0) {
602		perror("F_SETFD");
603		return -1;
604	}
605	sprintf(proc, "/proc/%d/status", tcp->pid);
606	if ((tcp->pfd_stat = open(proc, O_RDONLY|O_EXCL)) < 0) {
607		perror("strace: open(\"/proc/...\", ...)");
608		return -1;
609	}
610	if ((arg = fcntl(tcp->pfd_stat, F_GETFD)) < 0) {
611		perror("F_GETFD");
612		return -1;
613	}
614	if (fcntl(tcp->pfd_stat, F_SETFD, arg|FD_CLOEXEC) < 0) {
615		perror("F_SETFD");
616		return -1;
617	}
618	sprintf(proc, "/proc/%d/as", tcp->pid);
619	if ((tcp->pfd_as = open(proc, O_RDONLY|O_EXCL)) < 0) {
620		perror("strace: open(\"/proc/...\", ...)");
621		return -1;
622	}
623	if ((arg = fcntl(tcp->pfd_as, F_GETFD)) < 0) {
624		perror("F_GETFD");
625		return -1;
626	}
627	if (fcntl(tcp->pfd_as, F_SETFD, arg|FD_CLOEXEC) < 0) {
628		perror("F_SETFD");
629		return -1;
630	}
631#else
632	/* Open the process pseudo-file in /proc. */
633	sprintf(proc, "/proc/%d", tcp->pid);
634	if ((tcp->pfd = open(proc, O_RDWR|O_EXCL)) < 0) {
635		perror("strace: open(\"/proc/...\", ...)");
636		return -1;
637	}
638	if ((arg = fcntl(tcp->pfd, F_GETFD)) < 0) {
639		perror("F_GETFD");
640		return -1;
641	}
642	if (fcntl(tcp->pfd, F_SETFD, arg|FD_CLOEXEC) < 0) {
643		perror("F_SETFD");
644		return -1;
645	}
646#endif
647	rebuild_pollv();
648	if (!attaching) {
649		/*
650		 * Wait for the child to pause.  Because of a race
651		 * condition we have to poll for the event.
652		 */
653		for (;;) {
654			if (IOCTL_STATUS (tcp) < 0) {
655				perror("strace: PIOCSTATUS");
656				return -1;
657			}
658			if (tcp->status.PR_FLAGS & PR_ASLEEP)
659				break;
660		}
661	}
662	/* Stop the process so that we own the stop. */
663	if (IOCTL(tcp->pfd, PIOCSTOP, (char *)NULL) < 0) {
664		perror("strace: PIOCSTOP");
665		return -1;
666	}
667#ifdef PIOCSET
668	/* Set Run-on-Last-Close. */
669	arg = PR_RLC;
670	if (IOCTL(tcp->pfd, PIOCSET, &arg) < 0) {
671		perror("PIOCSET PR_RLC");
672		return -1;
673	}
674	/* Set or Reset Inherit-on-Fork. */
675	arg = PR_FORK;
676	if (IOCTL(tcp->pfd, followfork ? PIOCSET : PIOCRESET, &arg) < 0) {
677		perror("PIOC{SET,RESET} PR_FORK");
678		return -1;
679	}
680#else  /* !PIOCSET */
681	if (ioctl(tcp->pfd, PIOCSRLC) < 0) {
682		perror("PIOCSRLC");
683		return -1;
684	}
685	if (ioctl(tcp->pfd, followfork ? PIOCSFORK : PIOCRFORK) < 0) {
686		perror("PIOC{S,R}FORK");
687		return -1;
688	}
689#endif /* !PIOCSET */
690	/* Enable all syscall entries. */
691	prfillset(&sc_enter);
692	if (IOCTL(tcp->pfd, PIOCSENTRY, &sc_enter) < 0) {
693		perror("PIOCSENTRY");
694		return -1;
695	}
696	/* Enable all syscall exits. */
697	prfillset(&sc_exit);
698	if (IOCTL(tcp->pfd, PIOCSEXIT, &sc_exit) < 0) {
699		perror("PIOSEXIT");
700		return -1;
701	}
702	/* Enable all signals. */
703	prfillset(&signals);
704	if (IOCTL(tcp->pfd, PIOCSTRACE, &signals) < 0) {
705		perror("PIOCSTRACE");
706		return -1;
707	}
708	/* Enable all faults. */
709	prfillset(&faults);
710	if (IOCTL(tcp->pfd, PIOCSFAULT, &faults) < 0) {
711		perror("PIOCSFAULT");
712		return -1;
713	}
714	if (!attaching) {
715#ifdef MIPS
716		/*
717		 * The SGI PRSABORT doesn't work for pause() so
718		 * we send it a caught signal to wake it up.
719		 */
720		kill(tcp->pid, SIGINT);
721#else /* !MIPS */
722		/* The child is in a pause(), abort it. */
723		arg = PRSABORT;
724		if (IOCTL (tcp->pfd, PIOCRUN, &arg) < 0) {
725			perror("PIOCRUN");
726			return -1;
727		}
728#endif /* !MIPS */
729		for (;;) {
730			/* Wait for the child to do something. */
731			if (IOCTL_WSTOP (tcp) < 0) {
732				perror("PIOCWSTOP");
733				return -1;
734			}
735			if (tcp->status.PR_WHY == PR_SYSENTRY) {
736#ifdef HAVE_PR_SYSCALL
737				int scno = tcp->status.pr_syscall;
738#else /* !HAVE_PR_SYSCALL */
739				int scno = tcp->status.PR_WHAT;
740#endif /* !HAVE_PR_SYSCALL */
741				if (scno == SYS_execve)
742					break;
743			}
744			/* Set it running: maybe execve will be next. */
745			arg = 0;
746			if (IOCTL(tcp->pfd, PIOCRUN, &arg) < 0) {
747				perror("PIOCRUN");
748				return -1;
749			}
750		}
751	}
752#ifndef HAVE_POLLABLE_PROCFS
753	if (proc_poll_pipe[0] != -1)
754		proc_poller(tcp->pfd);
755	else if (nprocs > 1) {
756		proc_poll_open();
757		proc_poller(last_pfd);
758		proc_poller(tcp->pfd);
759	}
760	last_pfd = tcp->pfd;
761#endif /* !HAVE_POLLABLE_PROCFS */
762	return 0;
763}
764
765#endif /* SVR4 */
766
767static struct tcb *
768pid2tcb(pid)
769int pid;
770{
771	int i;
772	struct tcb *tcp;
773
774	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
775		if (pid && tcp->pid != pid)
776			continue;
777		if (tcp->flags & TCB_INUSE)
778			return tcp;
779	}
780	return NULL;
781}
782
783#ifdef SVR4
784
785static struct tcb *
786pfd2tcb(pfd)
787int pfd;
788{
789	int i;
790	struct tcb *tcp;
791
792	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
793		if (tcp->pfd != pfd)
794			continue;
795		if (tcp->flags & TCB_INUSE)
796			return tcp;
797	}
798	return NULL;
799}
800
801#endif /* SVR4 */
802
803void
804droptcb(tcp)
805struct tcb *tcp;
806{
807	if (tcp->pid == 0)
808		return;
809	nprocs--;
810	tcp->pid = 0;
811	tcp->flags = 0;
812	if (tcp->pfd != -1) {
813		close(tcp->pfd);
814		tcp->pfd = -1;
815#ifdef SVR4
816		rebuild_pollv();
817#endif
818	}
819	if (tcp->parent != NULL) {
820		tcp->parent->nchildren--;
821		tcp->parent = NULL;
822	}
823#if 0
824	if (tcp->outf != stderr)
825		fclose(tcp->outf);
826#endif
827	tcp->outf = 0;
828}
829
830#ifndef SVR4
831
832static int
833resume(tcp)
834struct tcb *tcp;
835{
836	if (tcp == NULL)
837		return -1;
838
839	if (!(tcp->flags & TCB_SUSPENDED)) {
840		fprintf(stderr, "PANIC: pid %u not suspended\n", tcp->pid);
841		return -1;
842	}
843	tcp->flags &= ~TCB_SUSPENDED;
844
845	if (ptrace(PTRACE_SYSCALL, tcp->pid, (char *) 1, 0) < 0) {
846		perror("resume: ptrace(PTRACE_SYSCALL, ...)");
847		return -1;
848	}
849
850	if (!qflag)
851		fprintf(stderr, "Process %u resumed\n", tcp->pid);
852	return 0;
853}
854
855#endif /* !SVR4 */
856
857/* detach traced process; continue with sig */
858
859static int
860detach(tcp, sig)
861struct tcb *tcp;
862int sig;
863{
864	int error = 0;
865#ifdef LINUX
866	int status;
867#endif
868
869	if (tcp->flags & TCB_BPTSET)
870		sig = SIGKILL;
871
872#ifdef LINUX
873	/*
874	 * Linux wrongly insists the child be stopped
875	 * before detaching.  Arghh.  We go through hoops
876	 * to make a clean break of things.
877	 */
878#if defined(SPARC)
879#undef PTRACE_DETACH
880#define PTRACE_DETACH PTRACE_SUNDETACH
881#endif
882	if ((error = ptrace(PTRACE_DETACH, tcp->pid, (char *) 1, sig)) == 0) {
883		/* On a clear day, you can see forever. */
884	}
885	else if (errno != ESRCH) {
886		/* Shouldn't happen. */
887		perror("detach: ptrace(PTRACE_DETACH, ...)");
888	}
889	else if (kill(tcp->pid, 0) < 0) {
890		if (errno != ESRCH)
891			perror("detach: checking sanity");
892	}
893	else if (kill(tcp->pid, SIGSTOP) < 0) {
894		if (errno != ESRCH)
895			perror("detach: stopping child");
896	}
897	else {
898		for (;;) {
899			if (waitpid(tcp->pid, &status, 0) < 0) {
900				if (errno != ECHILD)
901					perror("detach: waiting");
902				break;
903			}
904			if (!WIFSTOPPED(status)) {
905				/* Au revoir, mon ami. */
906				break;
907			}
908			if (WSTOPSIG(status) == SIGSTOP) {
909				if ((error = ptrace(PTRACE_DETACH,
910				    tcp->pid, (char *) 1, sig)) < 0) {
911					if (errno != ESRCH)
912						perror("detach: ptrace(PTRACE_DETACH, ...)");
913					/* I died trying. */
914				}
915				break;
916			}
917			if ((error = ptrace(PTRACE_CONT, tcp->pid, (char *) 1,
918			    WSTOPSIG(status) == SIGTRAP ?
919			    0 : WSTOPSIG(status))) < 0) {
920				if (errno != ESRCH)
921					perror("detach: ptrace(PTRACE_CONT, ...)");
922				break;
923			}
924		}
925	}
926#endif /* LINUX */
927
928#if defined(SUNOS4)
929	/* PTRACE_DETACH won't respect `sig' argument, so we post it here. */
930	if (sig && kill(tcp->pid, sig) < 0)
931		perror("detach: kill");
932	sig = 0;
933	if ((error = ptrace(PTRACE_DETACH, tcp->pid, (char *) 1, sig)) < 0)
934		perror("detach: ptrace(PTRACE_DETACH, ...)");
935#endif /* SUNOS4 */
936
937#ifndef SVR4
938	if (waiting_parent(tcp))
939		error = resume(tcp->parent);
940#endif /* !SVR4 */
941
942	if (!qflag)
943		fprintf(stderr, "Process %u detached\n", tcp->pid);
944
945	droptcb(tcp);
946	return error;
947}
948
949#ifdef SVR4
950
951static void
952reaper(sig)
953int sig;
954{
955	int pid;
956	int status;
957
958	while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
959#if 0
960		struct tcb *tcp;
961
962		tcp = pid2tcb(pid);
963		if (tcp)
964			droptcb(tcp);
965#endif
966	}
967}
968
969#endif /* SVR4 */
970
971static void
972cleanup()
973{
974	int i;
975	struct tcb *tcp;
976
977	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
978		if (!(tcp->flags & TCB_INUSE))
979			continue;
980		if (debug)
981			fprintf(stderr,
982				"cleanup: looking at pid %u\n", tcp->pid);
983		if (tcp_last &&
984		    (!outfname || followfork < 2 || tcp_last == tcp)) {
985			tprintf(" <unfinished ...>\n");
986			tcp_last = NULL;
987		}
988		if (tcp->flags & TCB_ATTACHED)
989			detach(tcp, 0);
990		else {
991			kill(tcp->pid, SIGCONT);
992			kill(tcp->pid, SIGTERM);
993		}
994	}
995	if (cflag)
996		call_summary(outf);
997}
998
999static void
1000interrupt(sig)
1001int sig;
1002{
1003	interrupted = 1;
1004}
1005
1006#ifndef HAVE_STRERROR
1007
1008#ifndef SYS_ERRLIST_DECLARED
1009extern int sys_nerr;
1010extern char *sys_errlist[];
1011#endif /* SYS_ERRLIST_DECLARED */
1012
1013const char *
1014strerror(errno)
1015int errno;
1016{
1017	static char buf[64];
1018
1019	if (errno < 1 || errno >= sys_nerr) {
1020		sprintf(buf, "Unknown error %d", errno);
1021		return buf;
1022	}
1023	return sys_errlist[errno];
1024}
1025
1026#endif /* HAVE_STERRROR */
1027
1028#ifndef HAVE_STRSIGNAL
1029
1030#ifndef SYS_SIGLIST_DECLARED
1031#ifdef HAVE__SYS_SIGLIST
1032	extern char *_sys_siglist[];
1033#else
1034	extern char *sys_siglist[];
1035#endif
1036#endif /* SYS_SIGLIST_DECLARED */
1037
1038const char *
1039strsignal(sig)
1040int sig;
1041{
1042	static char buf[64];
1043
1044	if (sig < 1 || sig >= NSIG) {
1045		sprintf(buf, "Unknown signal %d", sig);
1046		return buf;
1047	}
1048#ifdef HAVE__SYS_SIGLIST
1049	return _sys_siglist[sig];
1050#else
1051	return sys_siglist[sig];
1052#endif
1053}
1054
1055#endif /* HAVE_STRSIGNAL */
1056
1057#ifdef SVR4
1058
1059static void
1060rebuild_pollv()
1061{
1062	int i, j;
1063	struct tcb *tcp;
1064
1065	for (i = j = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
1066		if (!(tcp->flags & TCB_INUSE))
1067			continue;
1068		pollv[j].fd = tcp->pfd;
1069		pollv[j].events = POLLWANT;
1070		j++;
1071	}
1072	if (j != nprocs) {
1073		fprintf(stderr, "strace: proc miscount\n");
1074		exit(1);
1075	}
1076}
1077
1078#ifndef HAVE_POLLABLE_PROCFS
1079
1080static void
1081proc_poll_open()
1082{
1083	int arg;
1084	int i;
1085
1086	if (pipe(proc_poll_pipe) < 0) {
1087		perror("pipe");
1088		exit(1);
1089	}
1090	for (i = 0; i < 2; i++) {
1091		if ((arg = fcntl(proc_poll_pipe[i], F_GETFD)) < 0) {
1092			perror("F_GETFD");
1093			exit(1);
1094		}
1095		if (fcntl(proc_poll_pipe[i], F_SETFD, arg|FD_CLOEXEC) < 0) {
1096			perror("F_SETFD");
1097			exit(1);
1098		}
1099	}
1100}
1101
1102static int
1103proc_poll(pollv, nfds, timeout)
1104struct pollfd *pollv;
1105int nfds;
1106int timeout;
1107{
1108	int i;
1109	int n;
1110	struct proc_pollfd pollinfo;
1111
1112	if ((n = read(proc_poll_pipe[0], &pollinfo, sizeof(pollinfo))) < 0)
1113		return n;
1114	if (n != sizeof(struct proc_pollfd)) {
1115		fprintf(stderr, "panic: short read: %d\n", n);
1116		exit(1);
1117	}
1118	for (i = 0; i < nprocs; i++) {
1119		if (pollv[i].fd == pollinfo.fd)
1120			pollv[i].revents = pollinfo.revents;
1121		else
1122			pollv[i].revents = 0;
1123	}
1124	poller_pid = pollinfo.pid;
1125	return 1;
1126}
1127
1128static void
1129wakeup_handler(sig)
1130int sig;
1131{
1132}
1133
1134static void
1135proc_poller(pfd)
1136int pfd;
1137{
1138	struct proc_pollfd pollinfo;
1139	struct sigaction sa;
1140	sigset_t blocked_set, empty_set;
1141	int i;
1142	int n;
1143	struct rlimit rl;
1144
1145	switch (fork()) {
1146	case -1:
1147		perror("fork");
1148		_exit(0);
1149	case 0:
1150		break;
1151	default:
1152		return;
1153	}
1154
1155	sa.sa_handler = interactive ? SIG_DFL : SIG_IGN;
1156	sa.sa_flags = 0;
1157	sigemptyset(&sa.sa_mask);
1158	sigaction(SIGHUP, &sa, NULL);
1159	sigaction(SIGINT, &sa, NULL);
1160	sigaction(SIGQUIT, &sa, NULL);
1161	sigaction(SIGPIPE, &sa, NULL);
1162	sigaction(SIGTERM, &sa, NULL);
1163	sa.sa_handler = wakeup_handler;
1164	sigaction(SIGUSR1, &sa, NULL);
1165	sigemptyset(&blocked_set);
1166	sigaddset(&blocked_set, SIGUSR1);
1167	sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1168	sigemptyset(&empty_set);
1169
1170	if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
1171		perror("getrlimit(RLIMIT_NOFILE, ...)");
1172		_exit(0);
1173	}
1174	n = rl.rlim_cur;
1175	for (i = 0; i < n; i++) {
1176		if (i != pfd && i != proc_poll_pipe[1])
1177			close(i);
1178	}
1179
1180	pollinfo.fd = pfd;
1181	pollinfo.pid = getpid();
1182	for (;;) {
1183		if (ioctl(pfd, PIOCWSTOP, NULL) < 0)
1184		{
1185			switch (errno) {
1186			case EINTR:
1187				continue;
1188			case EBADF:
1189				pollinfo.revents = POLLERR;
1190				break;
1191			case ENOENT:
1192				pollinfo.revents = POLLHUP;
1193				break;
1194			default:
1195				perror("proc_poller: PIOCWSTOP");
1196			}
1197			write(proc_poll_pipe[1], &pollinfo, sizeof(pollinfo));
1198			_exit(0);
1199		}
1200		pollinfo.revents = POLLWANT;
1201		write(proc_poll_pipe[1], &pollinfo, sizeof(pollinfo));
1202		sigsuspend(&empty_set);
1203	}
1204}
1205
1206#endif /* !HAVE_POLLABLE_PROCFS */
1207
1208static int
1209choose_pfd()
1210{
1211	int i, j;
1212	struct tcb *tcp;
1213
1214	static int last;
1215
1216	if (followfork < 2 &&
1217	    last < nprocs && (pollv[last].revents & POLLWANT)) {
1218		/*
1219		 * The previous process is ready to run again.  We'll
1220		 * let it do so if it is currently in a syscall.  This
1221		 * heuristic improves the readability of the trace.
1222		 */
1223		tcp = pfd2tcb(pollv[last].fd);
1224		if (tcp && (tcp->flags & TCB_INSYSCALL))
1225			return pollv[last].fd;
1226	}
1227
1228	for (i = 0; i < nprocs; i++) {
1229		/* Let competing children run round robin. */
1230		j = (i + last + 1) % nprocs;
1231		if (pollv[j].revents & (POLLHUP | POLLERR)) {
1232			tcp = pfd2tcb(pollv[j].fd);
1233			if (!tcp) {
1234				fprintf(stderr, "strace: lost proc\n");
1235				exit(1);
1236			}
1237			droptcb(tcp);
1238			return -1;
1239		}
1240		if (pollv[j].revents & POLLWANT) {
1241			last = j;
1242			return pollv[j].fd;
1243		}
1244	}
1245	fprintf(stderr, "strace: nothing ready\n");
1246	exit(1);
1247}
1248
1249static int
1250trace()
1251{
1252#ifdef POLL_HACK
1253	struct tcb *in_syscall;
1254#endif
1255	struct tcb *tcp;
1256	int pfd;
1257	int what;
1258	int ioctl_result = 0, ioctl_errno = 0;
1259	long arg;
1260
1261	for (;;) {
1262		if (interactive)
1263			sigprocmask(SIG_SETMASK, &empty_set, NULL);
1264
1265		if (nprocs == 0)
1266			break;
1267
1268		switch (nprocs) {
1269		case 1:
1270#ifndef HAVE_POLLABLE_PROCFS
1271			if (proc_poll_pipe[0] == -1) {
1272#endif
1273				tcp = pid2tcb(0);
1274				if (!tcp)
1275					continue;
1276				pfd = tcp->pfd;
1277				if (pfd == -1)
1278					continue;
1279				break;
1280#ifndef HAVE_POLLABLE_PROCFS
1281			}
1282			/* fall through ... */
1283#endif /* !HAVE_POLLABLE_PROCFS */
1284		default:
1285#ifdef HAVE_POLLABLE_PROCFS
1286#ifdef POLL_HACK
1287		        /* On some systems (e.g. UnixWare) we get too much ugly
1288			   "unfinished..." stuff when multiple proceses are in
1289			   syscalls.  Here's a nasty hack */
1290
1291			if (in_syscall) {
1292				struct pollfd pv;
1293				tcp = in_syscall;
1294				in_syscall = NULL;
1295				pv.fd = tcp->pfd;
1296				pv.events = POLLWANT;
1297				if ((what = poll (&pv, 1, 1)) < 0) {
1298					if (interrupted)
1299						return 0;
1300					continue;
1301				}
1302				else if (what == 1 && pv.revents & POLLWANT) {
1303					goto FOUND;
1304				}
1305			}
1306#endif
1307
1308			if (poll(pollv, nprocs, INFTIM) < 0) {
1309				if (interrupted)
1310					return 0;
1311				continue;
1312			}
1313#else /* !HAVE_POLLABLE_PROCFS */
1314			if (proc_poll(pollv, nprocs, INFTIM) < 0) {
1315				if (interrupted)
1316					return 0;
1317				continue;
1318			}
1319#endif /* !HAVE_POLLABLE_PROCFS */
1320			pfd = choose_pfd();
1321			if (pfd == -1)
1322				continue;
1323			break;
1324		}
1325
1326		/* Look up `pfd' in our table. */
1327		if ((tcp = pfd2tcb(pfd)) == NULL) {
1328			fprintf(stderr, "unknown pfd: %u\n", pfd);
1329			exit(1);
1330		}
1331	FOUND:
1332		/* Get the status of the process. */
1333		if (!interrupted) {
1334			ioctl_result = IOCTL_WSTOP (tcp);
1335			ioctl_errno = errno;
1336#ifndef HAVE_POLLABLE_PROCFS
1337			if (proc_poll_pipe[0] != -1) {
1338				if (ioctl_result < 0)
1339					kill(poller_pid, SIGKILL);
1340				else
1341					kill(poller_pid, SIGUSR1);
1342			}
1343#endif /* !HAVE_POLLABLE_PROCFS */
1344		}
1345		if (interrupted)
1346			return 0;
1347
1348		if (interactive)
1349			sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1350
1351		if (ioctl_result < 0) {
1352			/* Find out what happened if it failed. */
1353			switch (ioctl_errno) {
1354			case EINTR:
1355			case EBADF:
1356				continue;
1357			case ENOENT:
1358				droptcb(tcp);
1359				continue;
1360			default:
1361				perror("PIOCWSTOP");
1362				exit(1);
1363			}
1364		}
1365
1366		/* clear the just started flag */
1367		tcp->flags &= ~TCB_STARTUP;
1368
1369		/* set current output file */
1370		outf = tcp->outf;
1371
1372		if (cflag) {
1373			struct timeval stime;
1374
1375			stime.tv_sec = tcp->status.pr_stime.tv_sec;
1376			stime.tv_usec = tcp->status.pr_stime.tv_nsec/1000;
1377			tv_sub(&tcp->dtime, &stime, &tcp->stime);
1378			tcp->stime = stime;
1379		}
1380
1381		what = tcp->status.PR_WHAT;
1382		switch (tcp->status.PR_WHY) {
1383		case PR_REQUESTED:
1384			if (tcp->status.PR_FLAGS & PR_ASLEEP) {
1385				tcp->status.PR_WHY = PR_SYSENTRY;
1386				if (trace_syscall(tcp) < 0) {
1387					fprintf(stderr, "syscall trouble\n");
1388					exit(1);
1389				}
1390			}
1391			break;
1392		case PR_SYSENTRY:
1393#ifdef POLL_HACK
1394		        in_syscall = tcp;
1395#endif
1396		case PR_SYSEXIT:
1397			if (trace_syscall(tcp) < 0) {
1398				fprintf(stderr, "syscall trouble\n");
1399				exit(1);
1400			}
1401			break;
1402		case PR_SIGNALLED:
1403			if (!cflag && (qual_flags[what] & QUAL_SIGNAL)) {
1404				printleader(tcp);
1405				tprintf("--- %s (%s) ---",
1406					signame(what), strsignal(what));
1407				printtrailer(tcp);
1408			}
1409			break;
1410		case PR_FAULTED:
1411			if (!cflag && (qual_flags[what] & QUAL_FAULT)) {
1412				printleader(tcp);
1413				tprintf("=== FAULT %d ===", what);
1414				printtrailer(tcp);
1415			}
1416			break;
1417		default:
1418			fprintf(stderr, "odd stop %d\n", tcp->status.PR_WHY);
1419			exit(1);
1420			break;
1421		}
1422		arg = 0;
1423		if (IOCTL (tcp->pfd, PIOCRUN, &arg) < 0) {
1424			perror("PIOCRUN");
1425			exit(1);
1426		}
1427	}
1428	return 0;
1429}
1430
1431#else /* !SVR4 */
1432
1433static int
1434trace()
1435{
1436	int pid;
1437	int wait_errno;
1438	int status;
1439	struct tcb *tcp;
1440#ifdef LINUX
1441	struct rusage ru;
1442#endif /* LINUX */
1443
1444	while (nprocs != 0) {
1445		if (interactive)
1446			sigprocmask(SIG_SETMASK, &empty_set, NULL);
1447#ifdef LINUX
1448		pid = wait4(-1, &status, 0, cflag ? &ru : NULL);
1449#endif /* LINUX */
1450#ifdef SUNOS4
1451		pid = wait(&status);
1452#endif /* SUNOS4 */
1453		wait_errno = errno;
1454		if (interactive)
1455			sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1456
1457		if (interrupted)
1458			return 0;
1459
1460		if (pid == -1) {
1461			switch (wait_errno) {
1462			case EINTR:
1463				continue;
1464			case ECHILD:
1465				/*
1466				 * We would like to verify this case
1467				 * but sometimes a race in Solbourne's
1468				 * version of SunOS sometimes reports
1469				 * ECHILD before sending us SIGCHILD.
1470				 */
1471#if 0
1472				if (nprocs == 0)
1473					return 0;
1474				fprintf(stderr, "strace: proc miscount\n");
1475				exit(1);
1476#endif
1477				return 0;
1478			default:
1479				errno = wait_errno;
1480				perror("strace: wait");
1481				return -1;
1482			}
1483		}
1484		if (debug)
1485			fprintf(stderr, " [wait(%#x) = %u]\n", status, pid);
1486
1487		/* Look up `pid' in our table. */
1488		if ((tcp = pid2tcb(pid)) == NULL) {
1489#if 0 /* XXX davidm */ /* WTA: disabled again */
1490			struct tcb *tcpchild;
1491
1492			if ((tcpchild = alloctcb(pid)) == NULL) {
1493				fprintf(stderr, " [tcb table full]\n");
1494				kill(pid, SIGKILL); /* XXX */
1495				return 0;
1496			}
1497			tcpchild->flags |= TCB_ATTACHED;
1498			newoutf(tcpchild);
1499			tcp->nchildren++;
1500			if (!qflag)
1501				fprintf(stderr, "Process %d attached\n", pid);
1502#else
1503			fprintf(stderr, "unknown pid: %u\n", pid);
1504			if (WIFSTOPPED(status))
1505				ptrace(PTRACE_CONT, pid, (char *) 1, 0);
1506			exit(1);
1507#endif
1508		}
1509		/* set current output file */
1510		outf = tcp->outf;
1511		if (cflag) {
1512#ifdef LINUX
1513			tv_sub(&tcp->dtime, &ru.ru_stime, &tcp->stime);
1514			tcp->stime = ru.ru_stime;
1515#endif /* !LINUX */
1516		}
1517
1518		if (tcp->flags & TCB_SUSPENDED) {
1519			/*
1520			 * Apparently, doing any ptrace() call on a stopped
1521			 * process, provokes the kernel to report the process
1522			 * status again on a subsequent wait(), even if the
1523			 * process has not been actually restarted.
1524			 * Since we have inspected the arguments of suspended
1525			 * processes we end up here testing for this case.
1526			 */
1527			continue;
1528		}
1529		if (WIFSIGNALED(status)) {
1530			if (!cflag
1531			    && (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)) {
1532				printleader(tcp);
1533				tprintf("+++ killed by %s +++",
1534					signame(WTERMSIG(status)));
1535				printtrailer(tcp);
1536			}
1537			droptcb(tcp);
1538			continue;
1539		}
1540		if (WIFEXITED(status)) {
1541			if (debug)
1542				fprintf(stderr, "pid %u exited\n", pid);
1543			if (tcp->flags & TCB_ATTACHED)
1544				fprintf(stderr,
1545					"PANIC: attached pid %u exited\n",
1546					pid);
1547			droptcb(tcp);
1548			continue;
1549		}
1550		if (!WIFSTOPPED(status)) {
1551			fprintf(stderr, "PANIC: pid %u not stopped\n", pid);
1552			droptcb(tcp);
1553			continue;
1554		}
1555		if (debug)
1556			fprintf(stderr, "pid %u stopped, [%s]\n",
1557				pid, signame(WSTOPSIG(status)));
1558
1559		if (tcp->flags & TCB_STARTUP) {
1560			/*
1561			 * This flag is there to keep us in sync.
1562			 * Next time this process stops it should
1563			 * really be entering a system call.
1564			 */
1565			tcp->flags &= ~TCB_STARTUP;
1566			if (tcp->flags & TCB_ATTACHED) {
1567				/*
1568				 * Interestingly, the process may stop
1569				 * with STOPSIG equal to some other signal
1570				 * than SIGSTOP if we happend to attach
1571				 * just before the process takes a signal.
1572				 */
1573				if (!WIFSTOPPED(status)) {
1574					fprintf(stderr,
1575						"pid %u not stopped\n", pid);
1576					detach(tcp, WSTOPSIG(status));
1577					continue;
1578				}
1579			}
1580			else {
1581#ifdef SUNOS4
1582				/* A child of us stopped at exec */
1583				if (WSTOPSIG(status) == SIGTRAP && followvfork)
1584					fixvfork(tcp);
1585#endif /* SUNOS4 */
1586			}
1587			if (tcp->flags & TCB_BPTSET) {
1588				if (clearbpt(tcp) < 0) /* Pretty fatal */ {
1589					droptcb(tcp);
1590					cleanup();
1591					return -1;
1592				}
1593			}
1594			goto tracing;
1595		}
1596
1597		if (WSTOPSIG(status) != SIGTRAP) {
1598			if (WSTOPSIG(status) == SIGSTOP &&
1599					(tcp->flags & TCB_SIGTRAPPED)) {
1600				/*
1601				 * Trapped attempt to block SIGTRAP
1602				 * Hope we are back in control now.
1603				 */
1604				tcp->flags &= ~(TCB_INSYSCALL | TCB_SIGTRAPPED);
1605				if (ptrace(PTRACE_SYSCALL,
1606						pid, (char *) 1, 0) < 0) {
1607					perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1608					cleanup();
1609					return -1;
1610				}
1611				continue;
1612			}
1613			if (!cflag
1614			    && (qual_flags[WSTOPSIG(status)] & QUAL_SIGNAL)) {
1615				printleader(tcp);
1616				tprintf("--- %s (%s) ---",
1617					signame(WSTOPSIG(status)),
1618					strsignal(WSTOPSIG(status)));
1619				printtrailer(tcp);
1620			}
1621			if ((tcp->flags & TCB_ATTACHED) &&
1622				!sigishandled(tcp, WSTOPSIG(status))) {
1623				detach(tcp, WSTOPSIG(status));
1624				continue;
1625			}
1626			if (ptrace(PTRACE_SYSCALL, pid, (char *) 1,
1627				   WSTOPSIG(status)) < 0) {
1628				perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1629				cleanup();
1630				return -1;
1631			}
1632			tcp->flags &= ~TCB_SUSPENDED;
1633			continue;
1634		}
1635		if (trace_syscall(tcp) < 0) {
1636			if (tcp->flags & TCB_ATTACHED)
1637				detach(tcp, 0);
1638			else {
1639				ptrace(PTRACE_KILL,
1640					tcp->pid, (char *) 1, SIGTERM);
1641				droptcb(tcp);
1642			}
1643			continue;
1644		}
1645		if (tcp->flags & TCB_EXITING) {
1646			if (tcp->flags & TCB_ATTACHED)
1647				detach(tcp, 0);
1648			else if (ptrace(PTRACE_CONT, pid, (char *) 1, 0) < 0) {
1649				perror("strace: ptrace(PTRACE_CONT, ...)");
1650				cleanup();
1651				return -1;
1652			}
1653			continue;
1654		}
1655		if (tcp->flags & TCB_SUSPENDED) {
1656			if (!qflag)
1657				fprintf(stderr, "Process %u suspended\n", pid);
1658			continue;
1659		}
1660	tracing:
1661		if (ptrace(PTRACE_SYSCALL, pid, (char *) 1, 0) < 0) {
1662			perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1663			cleanup();
1664			return -1;
1665		}
1666	}
1667	return 0;
1668}
1669
1670#endif /* !SVR4 */
1671
1672static int curcol;
1673
1674#ifdef __STDC__
1675#include <stdarg.h>
1676#define VA_START(a, b) va_start(a, b)
1677#else
1678#include <varargs.h>
1679#define VA_START(a, b) va_start(a)
1680#endif
1681
1682void
1683#ifdef __STDC__
1684tprintf(const char *fmt, ...)
1685#else
1686tprintf(fmt, va_alist)
1687char *fmt;
1688va_dcl
1689#endif
1690{
1691	va_list args;
1692
1693	VA_START(args, fmt);
1694	if (outf)
1695		curcol += vfprintf(outf, fmt, args);
1696	va_end(args);
1697	return;
1698}
1699
1700void
1701printleader(tcp)
1702struct tcb *tcp;
1703{
1704	if (tcp_last && (!outfname || followfork < 2 || tcp_last == tcp)) {
1705		tcp_last->flags |= TCB_REPRINT;
1706		tprintf(" <unfinished ...>\n");
1707	}
1708	curcol = 0;
1709	if ((followfork == 1 || pflag_seen > 1) && outfname)
1710		tprintf("%-5d ", tcp->pid);
1711	else if (nprocs > 1 && !outfname)
1712		tprintf("[pid %5u] ", tcp->pid);
1713	if (tflag) {
1714		char str[sizeof("HH:MM:SS")];
1715		struct timeval tv, dtv;
1716		static struct timeval otv;
1717
1718		gettimeofday(&tv, NULL);
1719		if (rflag) {
1720			if (otv.tv_sec == 0)
1721				otv = tv;
1722			tv_sub(&dtv, &tv, &otv);
1723			tprintf("%6ld.%06ld ",
1724				(long) dtv.tv_sec, (long) dtv.tv_usec);
1725			otv = tv;
1726		}
1727		else if (tflag > 2) {
1728			tprintf("%ld.%06ld ",
1729				(long) tv.tv_sec, (long) tv.tv_usec);
1730		}
1731		else {
1732			time_t local = tv.tv_sec;
1733			strftime(str, sizeof(str), "%T", localtime(&local));
1734			if (tflag > 1)
1735				tprintf("%s.%06ld ", str, (long) tv.tv_usec);
1736			else
1737				tprintf("%s ", str);
1738		}
1739	}
1740	if (iflag)
1741		printcall(tcp);
1742}
1743
1744void
1745tabto(col)
1746int col;
1747{
1748	if (curcol < col)
1749		tprintf("%*s", col - curcol, "");
1750}
1751
1752void
1753printtrailer(tcp)
1754struct tcb *tcp;
1755{
1756	tprintf("\n");
1757	tcp_last = NULL;
1758}
1759
1760#ifdef HAVE_MP_PROCFS
1761
1762int mp_ioctl (int fd, int cmd, void *arg, int size) {
1763
1764	struct iovec iov[2];
1765	int n = 1;
1766
1767	iov[0].iov_base = &cmd;
1768	iov[0].iov_len = sizeof cmd;
1769	if (arg) {
1770		++n;
1771		iov[1].iov_base = arg;
1772		iov[1].iov_len = size;
1773	}
1774
1775	return writev (fd, iov, n);
1776}
1777
1778#endif
1779