strace.c revision 2ee6e45f36566e8735b35ffad40bfcc626a25a98 
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 (ptrace(PTRACE_TRACEME, 0, (char *) 1, 0) < 0) {
423				perror("strace: ptrace(PTRACE_TRACEME, ...)");
424				return -1;
425			}
426			if (debug)
427				kill(getpid(), SIGSTOP);
428
429			if (username != NULL || geteuid() == 0) {
430				uid_t run_euid = run_uid;
431				gid_t run_egid = run_gid;
432
433				if (statbuf.st_mode & S_ISUID)
434					run_euid = statbuf.st_uid;
435				if (statbuf.st_mode & S_ISGID)
436					run_egid = statbuf.st_gid;
437
438				/*
439				 * It is important to set groups before we
440				 * lose privileges on setuid.
441				 */
442				if (username != NULL
443				    && initgroups(username, run_gid) < 0) {
444					perror("initgroups");
445					exit(1);
446				}
447				if (setregid(run_gid, run_egid) < 0) {
448					perror("setregid");
449					exit(1);
450				}
451				if (setreuid(run_uid, run_euid) < 0) {
452					perror("setreuid");
453					exit(1);
454				}
455			}
456			else
457				setreuid(run_uid, run_uid);
458#endif /* !SVR4 */
459
460			execv(pathname, &argv[optind]);
461			perror("strace: exec");
462			_exit(1);
463			break;
464		}
465		default:
466			if ((tcp = alloctcb(pid)) == NULL) {
467				fprintf(stderr, "tcb table full\n");
468				cleanup();
469				exit(1);
470			}
471#ifdef SVR4
472			if (proc_open(tcp, 0) < 0) {
473				fprintf(stderr, "trouble opening proc file\n");
474				cleanup();
475				exit(1);
476			}
477#endif /* SVR4 */
478#ifndef SVR4
479			fake_execve(tcp, pathname, &argv[optind], environ);
480#endif
481			break;
482		}
483	}
484	else if (pflag_seen == 0)
485		usage(stderr, 1);
486
487	sigemptyset(&empty_set);
488	sigemptyset(&blocked_set);
489	sa.sa_handler = SIG_IGN;
490	sigemptyset(&sa.sa_mask);
491	sa.sa_flags = 0;
492	sigaction(SIGTTOU, &sa, NULL);
493	sigaction(SIGTTIN, &sa, NULL);
494	if (interactive) {
495		sigaddset(&blocked_set, SIGHUP);
496		sigaddset(&blocked_set, SIGINT);
497		sigaddset(&blocked_set, SIGQUIT);
498		sigaddset(&blocked_set, SIGPIPE);
499		sigaddset(&blocked_set, SIGTERM);
500		sa.sa_handler = interrupt;
501#ifdef SUNOS4
502		/* POSIX signals on sunos4.1 are a little broken. */
503		sa.sa_flags = SA_INTERRUPT;
504#endif /* SUNOS4 */
505	}
506	sigaction(SIGHUP, &sa, NULL);
507	sigaction(SIGINT, &sa, NULL);
508	sigaction(SIGQUIT, &sa, NULL);
509	sigaction(SIGPIPE, &sa, NULL);
510	sigaction(SIGTERM, &sa, NULL);
511#ifdef SVR4
512	sa.sa_handler = reaper;
513	sigaction(SIGCHLD, &sa, NULL);
514#endif /* SVR4 */
515
516	if (trace() < 0)
517		exit(1);
518	cleanup();
519	exit(0);
520}
521
522void
523newoutf(tcp)
524struct tcb *tcp;
525{
526	char name[MAXPATHLEN];
527	FILE *fp;
528
529	if (outfname && followfork > 1) {
530		sprintf(name, "%s.%u", outfname, tcp->pid);
531#ifndef SVR4
532		setreuid(geteuid(), getuid());
533#endif
534		fp = fopen(name, "w");
535#ifndef SVR4
536		setreuid(geteuid(), getuid());
537#endif
538		if (fp == NULL) {
539			perror("fopen");
540			return;
541		}
542		tcp->outf = fp;
543	}
544	return;
545}
546
547struct tcb *
548alloctcb(pid)
549int pid;
550{
551	int i;
552	struct tcb *tcp;
553
554	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
555		if ((tcp->flags & TCB_INUSE) == 0) {
556			tcp->pid = pid;
557			tcp->parent = NULL;
558			tcp->nchildren = 0;
559			tcp->flags = TCB_INUSE | TCB_STARTUP;
560			tcp->outf = outf; /* Initialise to current out file */
561			tcp->stime.tv_sec = 0;
562			tcp->stime.tv_usec = 0;
563			tcp->pfd = -1;
564			nprocs++;
565			return tcp;
566		}
567	}
568	return NULL;
569}
570
571#ifdef SVR4
572int
573proc_open(tcp, attaching)
574struct tcb *tcp;
575int attaching;
576{
577	char proc[32];
578	long arg;
579	sysset_t sc_enter, sc_exit;
580	sigset_t signals;
581	fltset_t faults;
582#ifndef HAVE_POLLABLE_PROCFS
583	static int last_pfd;
584#endif
585
586#ifdef HAVE_MP_PROCFS
587	/* Open the process pseudo-files in /proc. */
588	sprintf(proc, "/proc/%d/ctl", tcp->pid);
589	if ((tcp->pfd = open(proc, O_WRONLY|O_EXCL)) < 0) {
590		perror("strace: open(\"/proc/...\", ...)");
591		return -1;
592	}
593	if ((arg = fcntl(tcp->pfd, F_GETFD)) < 0) {
594		perror("F_GETFD");
595		return -1;
596	}
597	if (fcntl(tcp->pfd, F_SETFD, arg|FD_CLOEXEC) < 0) {
598		perror("F_SETFD");
599		return -1;
600	}
601	sprintf(proc, "/proc/%d/status", tcp->pid);
602	if ((tcp->pfd_stat = open(proc, O_RDONLY|O_EXCL)) < 0) {
603		perror("strace: open(\"/proc/...\", ...)");
604		return -1;
605	}
606	if ((arg = fcntl(tcp->pfd_stat, F_GETFD)) < 0) {
607		perror("F_GETFD");
608		return -1;
609	}
610	if (fcntl(tcp->pfd_stat, F_SETFD, arg|FD_CLOEXEC) < 0) {
611		perror("F_SETFD");
612		return -1;
613	}
614	sprintf(proc, "/proc/%d/as", tcp->pid);
615	if ((tcp->pfd_as = open(proc, O_RDONLY|O_EXCL)) < 0) {
616		perror("strace: open(\"/proc/...\", ...)");
617		return -1;
618	}
619	if ((arg = fcntl(tcp->pfd_as, F_GETFD)) < 0) {
620		perror("F_GETFD");
621		return -1;
622	}
623	if (fcntl(tcp->pfd_as, F_SETFD, arg|FD_CLOEXEC) < 0) {
624		perror("F_SETFD");
625		return -1;
626	}
627#else
628	/* Open the process pseudo-file in /proc. */
629	sprintf(proc, "/proc/%d", tcp->pid);
630	if ((tcp->pfd = open(proc, O_RDWR|O_EXCL)) < 0) {
631		perror("strace: open(\"/proc/...\", ...)");
632		return -1;
633	}
634	if ((arg = fcntl(tcp->pfd, F_GETFD)) < 0) {
635		perror("F_GETFD");
636		return -1;
637	}
638	if (fcntl(tcp->pfd, F_SETFD, arg|FD_CLOEXEC) < 0) {
639		perror("F_SETFD");
640		return -1;
641	}
642#endif
643	rebuild_pollv();
644	if (!attaching) {
645		/*
646		 * Wait for the child to pause.  Because of a race
647		 * condition we have to poll for the event.
648		 */
649		for (;;) {
650			if (IOCTL_STATUS (tcp) < 0) {
651				perror("strace: PIOCSTATUS");
652				return -1;
653			}
654			if (tcp->status.PR_FLAGS & PR_ASLEEP)
655				break;
656		}
657	}
658	/* Stop the process so that we own the stop. */
659	if (IOCTL(tcp->pfd, PIOCSTOP, NULL) < 0) {
660		perror("strace: PIOCSTOP");
661		return -1;
662	}
663#ifdef PIOCSET
664	/* Set Run-on-Last-Close. */
665	arg = PR_RLC;
666	if (IOCTL(tcp->pfd, PIOCSET, &arg) < 0) {
667		perror("PIOCSET PR_RLC");
668		return -1;
669	}
670	/* Set or Reset Inherit-on-Fork. */
671	arg = PR_FORK;
672	if (IOCTL(tcp->pfd, followfork ? PIOCSET : PIOCRESET, &arg) < 0) {
673		perror("PIOC{SET,RESET} PR_FORK");
674		return -1;
675	}
676#else  /* !PIOCSET */
677	if (ioctl(tcp->pfd, PIOCSRLC) < 0) {
678		perror("PIOCSRLC");
679		return -1;
680	}
681	if (ioctl(tcp->pfd, followfork ? PIOCSFORK : PIOCRFORK) < 0) {
682		perror("PIOC{S,R}FORK");
683		return -1;
684	}
685#endif /* !PIOCSET */
686	/* Enable all syscall entries. */
687	prfillset(&sc_enter);
688	if (IOCTL(tcp->pfd, PIOCSENTRY, &sc_enter) < 0) {
689		perror("PIOCSENTRY");
690		return -1;
691	}
692	/* Enable all syscall exits. */
693	prfillset(&sc_exit);
694	if (IOCTL(tcp->pfd, PIOCSEXIT, &sc_exit) < 0) {
695		perror("PIOSEXIT");
696		return -1;
697	}
698	/* Enable all signals. */
699	prfillset(&signals);
700	if (IOCTL(tcp->pfd, PIOCSTRACE, &signals) < 0) {
701		perror("PIOCSTRACE");
702		return -1;
703	}
704	/* Enable all faults. */
705	prfillset(&faults);
706	if (IOCTL(tcp->pfd, PIOCSFAULT, &faults) < 0) {
707		perror("PIOCSFAULT");
708		return -1;
709	}
710	if (!attaching) {
711#ifdef MIPS
712		/*
713		 * The SGI PRSABORT doesn't work for pause() so
714		 * we send it a caught signal to wake it up.
715		 */
716		kill(tcp->pid, SIGINT);
717#else /* !MIPS */
718		/* The child is in a pause(), abort it. */
719		arg = PRSABORT;
720		if (IOCTL (tcp->pfd, PIOCRUN, &arg) < 0) {
721			perror("PIOCRUN");
722			return -1;
723		}
724#endif /* !MIPS */
725		for (;;) {
726			/* Wait for the child to do something. */
727			if (IOCTL_WSTOP (tcp) < 0) {
728				perror("PIOCWSTOP");
729				return -1;
730			}
731			if (tcp->status.PR_WHY == PR_SYSENTRY) {
732#ifdef HAVE_PR_SYSCALL
733				int scno = tcp->status.pr_syscall;
734#else /* !HAVE_PR_SYSCALL */
735				int scno = tcp->status.PR_WHAT;
736#endif /* !HAVE_PR_SYSCALL */
737				if (scno == SYS_execve)
738					break;
739			}
740			/* Set it running: maybe execve will be next. */
741			arg = 0;
742			if (IOCTL(tcp->pfd, PIOCRUN, &arg) < 0) {
743				perror("PIOCRUN");
744				return -1;
745			}
746		}
747	}
748#ifndef HAVE_POLLABLE_PROCFS
749	if (proc_poll_pipe[0] != -1)
750		proc_poller(tcp->pfd);
751	else if (nprocs > 1) {
752		proc_poll_open();
753		proc_poller(last_pfd);
754		proc_poller(tcp->pfd);
755	}
756	last_pfd = tcp->pfd;
757#endif /* !HAVE_POLLABLE_PROCFS */
758	return 0;
759}
760
761#endif /* SVR4 */
762
763static struct tcb *
764pid2tcb(pid)
765int pid;
766{
767	int i;
768	struct tcb *tcp;
769
770	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
771		if (pid && tcp->pid != pid)
772			continue;
773		if (tcp->flags & TCB_INUSE)
774			return tcp;
775	}
776	return NULL;
777}
778
779#ifdef SVR4
780
781static struct tcb *
782pfd2tcb(pfd)
783int pfd;
784{
785	int i;
786	struct tcb *tcp;
787
788	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
789		if (tcp->pfd != pfd)
790			continue;
791		if (tcp->flags & TCB_INUSE)
792			return tcp;
793	}
794	return NULL;
795}
796
797#endif /* SVR4 */
798
799void
800droptcb(tcp)
801struct tcb *tcp;
802{
803	if (tcp->pid == 0)
804		return;
805	nprocs--;
806	tcp->pid = 0;
807	tcp->flags = 0;
808	if (tcp->pfd != -1) {
809		close(tcp->pfd);
810		tcp->pfd = -1;
811#ifdef SVR4
812		rebuild_pollv();
813#endif
814	}
815	if (tcp->parent != NULL) {
816		tcp->parent->nchildren--;
817		tcp->parent = NULL;
818	}
819#if 0
820	if (tcp->outf != stderr)
821		fclose(tcp->outf);
822#endif
823	tcp->outf = 0;
824}
825
826#ifndef SVR4
827
828static int
829resume(tcp)
830struct tcb *tcp;
831{
832	if (tcp == NULL)
833		return -1;
834
835	if (!(tcp->flags & TCB_SUSPENDED)) {
836		fprintf(stderr, "PANIC: pid %u not suspended\n", tcp->pid);
837		return -1;
838	}
839	tcp->flags &= ~TCB_SUSPENDED;
840
841	if (ptrace(PTRACE_SYSCALL, tcp->pid, (char *) 1, 0) < 0) {
842		perror("resume: ptrace(PTRACE_SYSCALL, ...)");
843		return -1;
844	}
845
846	if (!qflag)
847		fprintf(stderr, "Process %u resumed\n", tcp->pid);
848	return 0;
849}
850
851#endif /* !SVR4 */
852
853/* detach traced process; continue with sig */
854
855static int
856detach(tcp, sig)
857struct tcb *tcp;
858int sig;
859{
860	int error = 0;
861#ifdef LINUX
862	int status;
863#endif
864
865	if (tcp->flags & TCB_BPTSET)
866		sig = SIGKILL;
867
868#ifdef LINUX
869	/*
870	 * Linux wrongly insists the child be stopped
871	 * before detaching.  Arghh.  We go through hoops
872	 * to make a clean break of things.
873	 */
874#if defined(SPARC)
875#undef PTRACE_DETACH
876#define PTRACE_DETACH PTRACE_SUNDETACH
877#endif
878	if ((error = ptrace(PTRACE_DETACH, tcp->pid, (char *) 1, sig)) == 0) {
879		/* On a clear day, you can see forever. */
880	}
881	else if (errno != ESRCH) {
882		/* Shouldn't happen. */
883		perror("detach: ptrace(PTRACE_DETACH, ...)");
884	}
885	else if (kill(tcp->pid, 0) < 0) {
886		if (errno != ESRCH)
887			perror("detach: checking sanity");
888	}
889	else if (kill(tcp->pid, SIGSTOP) < 0) {
890		if (errno != ESRCH)
891			perror("detach: stopping child");
892	}
893	else {
894		for (;;) {
895			if (waitpid(tcp->pid, &status, 0) < 0) {
896				if (errno != ECHILD)
897					perror("detach: waiting");
898				break;
899			}
900			if (!WIFSTOPPED(status)) {
901				/* Au revoir, mon ami. */
902				break;
903			}
904			if (WSTOPSIG(status) == SIGSTOP) {
905				if ((error = ptrace(PTRACE_DETACH,
906				    tcp->pid, (char *) 1, sig)) < 0) {
907					if (errno != ESRCH)
908						perror("detach: ptrace(PTRACE_DETACH, ...)");
909					/* I died trying. */
910				}
911				break;
912			}
913			if ((error = ptrace(PTRACE_CONT, tcp->pid, (char *) 1,
914			    WSTOPSIG(status) == SIGTRAP ?
915			    0 : WSTOPSIG(status))) < 0) {
916				if (errno != ESRCH)
917					perror("detach: ptrace(PTRACE_CONT, ...)");
918				break;
919			}
920		}
921	}
922#endif /* LINUX */
923
924#if defined(SUNOS4)
925	/* PTRACE_DETACH won't respect `sig' argument, so we post it here. */
926	if (sig && kill(tcp->pid, sig) < 0)
927		perror("detach: kill");
928	sig = 0;
929	if ((error = ptrace(PTRACE_DETACH, tcp->pid, (char *) 1, sig)) < 0)
930		perror("detach: ptrace(PTRACE_DETACH, ...)");
931#endif /* SUNOS4 */
932
933#ifndef SVR4
934	if (waiting_parent(tcp))
935		error = resume(tcp->parent);
936#endif /* !SVR4 */
937
938	if (!qflag)
939		fprintf(stderr, "Process %u detached\n", tcp->pid);
940
941	droptcb(tcp);
942	return error;
943}
944
945#ifdef SVR4
946
947static void
948reaper(sig)
949int sig;
950{
951	int pid;
952	int status;
953
954	while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
955#if 0
956		struct tcb *tcp;
957
958		tcp = pid2tcb(pid);
959		if (tcp)
960			droptcb(tcp);
961#endif
962	}
963}
964
965#endif /* SVR4 */
966
967static void
968cleanup()
969{
970	int i;
971	struct tcb *tcp;
972
973	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
974		if (!(tcp->flags & TCB_INUSE))
975			continue;
976		if (debug)
977			fprintf(stderr,
978				"cleanup: looking at pid %u\n", tcp->pid);
979		if (tcp_last &&
980		    (!outfname || followfork < 2 || tcp_last == tcp)) {
981			tprintf(" <unfinished ...>\n");
982			tcp_last = NULL;
983		}
984		if (tcp->flags & TCB_ATTACHED)
985			detach(tcp, 0);
986		else {
987			kill(tcp->pid, SIGCONT);
988			kill(tcp->pid, SIGTERM);
989		}
990	}
991	if (cflag)
992		call_summary(outf);
993}
994
995static void
996interrupt(sig)
997int sig;
998{
999	interrupted = 1;
1000}
1001
1002#ifndef HAVE_STRERROR
1003
1004#ifndef SYS_ERRLIST_DECLARED
1005extern int sys_nerr;
1006extern char *sys_errlist[];
1007#endif /* SYS_ERRLIST_DECLARED */
1008
1009const char *
1010strerror(errno)
1011int errno;
1012{
1013	static char buf[64];
1014
1015	if (errno < 1 || errno >= sys_nerr) {
1016		sprintf(buf, "Unknown error %d", errno);
1017		return buf;
1018	}
1019	return sys_errlist[errno];
1020}
1021
1022#endif /* HAVE_STERRROR */
1023
1024#ifndef HAVE_STRSIGNAL
1025
1026#ifndef SYS_SIGLIST_DECLARED
1027#ifdef HAVE__SYS_SIGLIST
1028	extern char *_sys_siglist[];
1029#else
1030	extern char *sys_siglist[];
1031#endif
1032#endif /* SYS_SIGLIST_DECLARED */
1033
1034const char *
1035strsignal(sig)
1036int sig;
1037{
1038	static char buf[64];
1039
1040	if (sig < 1 || sig >= NSIG) {
1041		sprintf(buf, "Unknown signal %d", sig);
1042		return buf;
1043	}
1044#ifdef HAVE__SYS_SIGLIST
1045	return _sys_siglist[sig];
1046#else
1047	return sys_siglist[sig];
1048#endif
1049}
1050
1051#endif /* HAVE_STRSIGNAL */
1052
1053#ifdef SVR4
1054
1055static void
1056rebuild_pollv()
1057{
1058	int i, j;
1059	struct tcb *tcp;
1060
1061	for (i = j = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
1062		if (!(tcp->flags & TCB_INUSE))
1063			continue;
1064		pollv[j].fd = tcp->pfd;
1065		pollv[j].events = POLLWANT;
1066		j++;
1067	}
1068	if (j != nprocs) {
1069		fprintf(stderr, "strace: proc miscount\n");
1070		exit(1);
1071	}
1072}
1073
1074#ifndef HAVE_POLLABLE_PROCFS
1075
1076static void
1077proc_poll_open()
1078{
1079	int arg;
1080	int i;
1081
1082	if (pipe(proc_poll_pipe) < 0) {
1083		perror("pipe");
1084		exit(1);
1085	}
1086	for (i = 0; i < 2; i++) {
1087		if ((arg = fcntl(proc_poll_pipe[i], F_GETFD)) < 0) {
1088			perror("F_GETFD");
1089			exit(1);
1090		}
1091		if (fcntl(proc_poll_pipe[i], F_SETFD, arg|FD_CLOEXEC) < 0) {
1092			perror("F_SETFD");
1093			exit(1);
1094		}
1095	}
1096}
1097
1098static int
1099proc_poll(pollv, nfds, timeout)
1100struct pollfd *pollv;
1101int nfds;
1102int timeout;
1103{
1104	int i;
1105	int n;
1106	struct proc_pollfd pollinfo;
1107
1108	if ((n = read(proc_poll_pipe[0], &pollinfo, sizeof(pollinfo))) < 0)
1109		return n;
1110	if (n != sizeof(struct proc_pollfd)) {
1111		fprintf(stderr, "panic: short read: %d\n", n);
1112		exit(1);
1113	}
1114	for (i = 0; i < nprocs; i++) {
1115		if (pollv[i].fd == pollinfo.fd)
1116			pollv[i].revents = pollinfo.revents;
1117		else
1118			pollv[i].revents = 0;
1119	}
1120	poller_pid = pollinfo.pid;
1121	return 1;
1122}
1123
1124static void
1125wakeup_handler(sig)
1126int sig;
1127{
1128}
1129
1130static void
1131proc_poller(pfd)
1132int pfd;
1133{
1134	struct proc_pollfd pollinfo;
1135	struct sigaction sa;
1136	sigset_t blocked_set, empty_set;
1137	int i;
1138	int n;
1139	struct rlimit rl;
1140
1141	switch (fork()) {
1142	case -1:
1143		perror("fork");
1144		_exit(0);
1145	case 0:
1146		break;
1147	default:
1148		return;
1149	}
1150
1151	sa.sa_handler = interactive ? SIG_DFL : SIG_IGN;
1152	sa.sa_flags = 0;
1153	sigemptyset(&sa.sa_mask);
1154	sigaction(SIGHUP, &sa, NULL);
1155	sigaction(SIGINT, &sa, NULL);
1156	sigaction(SIGQUIT, &sa, NULL);
1157	sigaction(SIGPIPE, &sa, NULL);
1158	sigaction(SIGTERM, &sa, NULL);
1159	sa.sa_handler = wakeup_handler;
1160	sigaction(SIGUSR1, &sa, NULL);
1161	sigemptyset(&blocked_set);
1162	sigaddset(&blocked_set, SIGUSR1);
1163	sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1164	sigemptyset(&empty_set);
1165
1166	if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
1167		perror("getrlimit(RLIMIT_NOFILE, ...)");
1168		_exit(0);
1169	}
1170	n = rl.rlim_cur;
1171	for (i = 0; i < n; i++) {
1172		if (i != pfd && i != proc_poll_pipe[1])
1173			close(i);
1174	}
1175
1176	pollinfo.fd = pfd;
1177	pollinfo.pid = getpid();
1178	for (;;) {
1179		if (ioctl(pfd, PIOCWSTOP, NULL) < 0)
1180		{
1181			switch (errno) {
1182			case EINTR:
1183				continue;
1184			case EBADF:
1185				pollinfo.revents = POLLERR;
1186				break;
1187			case ENOENT:
1188				pollinfo.revents = POLLHUP;
1189				break;
1190			default:
1191				perror("proc_poller: PIOCWSTOP");
1192			}
1193			write(proc_poll_pipe[1], &pollinfo, sizeof(pollinfo));
1194			_exit(0);
1195		}
1196		pollinfo.revents = POLLWANT;
1197		write(proc_poll_pipe[1], &pollinfo, sizeof(pollinfo));
1198		sigsuspend(&empty_set);
1199	}
1200}
1201
1202#endif /* !HAVE_POLLABLE_PROCFS */
1203
1204static int
1205choose_pfd()
1206{
1207	int i, j;
1208	struct tcb *tcp;
1209
1210	static int last;
1211
1212	if (followfork < 2 &&
1213	    last < nprocs && (pollv[last].revents & POLLWANT)) {
1214		/*
1215		 * The previous process is ready to run again.  We'll
1216		 * let it do so if it is currently in a syscall.  This
1217		 * heuristic improves the readability of the trace.
1218		 */
1219		tcp = pfd2tcb(pollv[last].fd);
1220		if (tcp && (tcp->flags & TCB_INSYSCALL))
1221			return pollv[last].fd;
1222	}
1223
1224	for (i = 0; i < nprocs; i++) {
1225		/* Let competing children run round robin. */
1226		j = (i + last + 1) % nprocs;
1227		if (pollv[j].revents & (POLLHUP | POLLERR)) {
1228			tcp = pfd2tcb(pollv[j].fd);
1229			if (!tcp) {
1230				fprintf(stderr, "strace: lost proc\n");
1231				exit(1);
1232			}
1233			droptcb(tcp);
1234			return -1;
1235		}
1236		if (pollv[j].revents & POLLWANT) {
1237			last = j;
1238			return pollv[j].fd;
1239		}
1240	}
1241	fprintf(stderr, "strace: nothing ready\n");
1242	exit(1);
1243}
1244
1245static int
1246trace()
1247{
1248#ifdef POLL_HACK
1249	struct tcb *in_syscall;
1250#endif
1251	struct tcb *tcp;
1252	int pfd;
1253	int what;
1254	int ioctl_result = 0, ioctl_errno = 0;
1255	long arg;
1256
1257	for (;;) {
1258		if (interactive)
1259			sigprocmask(SIG_SETMASK, &empty_set, NULL);
1260
1261		if (nprocs == 0)
1262			break;
1263
1264		switch (nprocs) {
1265		case 1:
1266#ifndef HAVE_POLLABLE_PROCFS
1267			if (proc_poll_pipe[0] == -1) {
1268#endif
1269				tcp = pid2tcb(0);
1270				if (!tcp)
1271					continue;
1272				pfd = tcp->pfd;
1273				if (pfd == -1)
1274					continue;
1275				break;
1276#ifndef HAVE_POLLABLE_PROCFS
1277			}
1278			/* fall through ... */
1279#endif /* !HAVE_POLLABLE_PROCFS */
1280		default:
1281#ifdef HAVE_POLLABLE_PROCFS
1282#ifdef POLL_HACK
1283		        /* On some systems (e.g. UnixWare) we get too much ugly
1284			   "unfinished..." stuff when multiple proceses are in
1285			   syscalls.  Here's a nasty hack */
1286
1287			if (in_syscall) {
1288				struct pollfd pv;
1289				tcp = in_syscall;
1290				in_syscall = NULL;
1291				pv.fd = tcp->pfd;
1292				pv.events = POLLWANT;
1293				if ((what = poll (&pv, 1, 1)) < 0) {
1294					if (interrupted)
1295						return 0;
1296					continue;
1297				}
1298				else if (what == 1 && pv.revents & POLLWANT) {
1299					goto FOUND;
1300				}
1301			}
1302#endif
1303
1304			if (poll(pollv, nprocs, INFTIM) < 0) {
1305				if (interrupted)
1306					return 0;
1307				continue;
1308			}
1309#else /* !HAVE_POLLABLE_PROCFS */
1310			if (proc_poll(pollv, nprocs, INFTIM) < 0) {
1311				if (interrupted)
1312					return 0;
1313				continue;
1314			}
1315#endif /* !HAVE_POLLABLE_PROCFS */
1316			pfd = choose_pfd();
1317			if (pfd == -1)
1318				continue;
1319			break;
1320		}
1321
1322		/* Look up `pfd' in our table. */
1323		if ((tcp = pfd2tcb(pfd)) == NULL) {
1324			fprintf(stderr, "unknown pfd: %u\n", pfd);
1325			exit(1);
1326		}
1327	FOUND:
1328		/* Get the status of the process. */
1329		if (!interrupted) {
1330			ioctl_result = IOCTL_WSTOP (tcp);
1331			ioctl_errno = errno;
1332#ifndef HAVE_POLLABLE_PROCFS
1333			if (proc_poll_pipe[0] != -1) {
1334				if (ioctl_result < 0)
1335					kill(poller_pid, SIGKILL);
1336				else
1337					kill(poller_pid, SIGUSR1);
1338			}
1339#endif /* !HAVE_POLLABLE_PROCFS */
1340		}
1341		if (interrupted)
1342			return 0;
1343
1344		if (interactive)
1345			sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1346
1347		if (ioctl_result < 0) {
1348			/* Find out what happened if it failed. */
1349			switch (ioctl_errno) {
1350			case EINTR:
1351			case EBADF:
1352				continue;
1353			case ENOENT:
1354				droptcb(tcp);
1355				continue;
1356			default:
1357				perror("PIOCWSTOP");
1358				exit(1);
1359			}
1360		}
1361
1362		/* clear the just started flag */
1363		tcp->flags &= ~TCB_STARTUP;
1364
1365		/* set current output file */
1366		outf = tcp->outf;
1367
1368		if (cflag) {
1369			struct timeval stime;
1370
1371			stime.tv_sec = tcp->status.pr_stime.tv_sec;
1372			stime.tv_usec = tcp->status.pr_stime.tv_nsec/1000;
1373			tv_sub(&tcp->dtime, &stime, &tcp->stime);
1374			tcp->stime = stime;
1375		}
1376
1377		what = tcp->status.PR_WHAT;
1378		switch (tcp->status.PR_WHY) {
1379		case PR_REQUESTED:
1380			if (tcp->status.PR_FLAGS & PR_ASLEEP) {
1381				tcp->status.PR_WHY = PR_SYSENTRY;
1382				if (trace_syscall(tcp) < 0) {
1383					fprintf(stderr, "syscall trouble\n");
1384					exit(1);
1385				}
1386			}
1387			break;
1388		case PR_SYSENTRY:
1389#ifdef POLL_HACK
1390		        in_syscall = tcp;
1391#endif
1392		case PR_SYSEXIT:
1393			if (trace_syscall(tcp) < 0) {
1394				fprintf(stderr, "syscall trouble\n");
1395				exit(1);
1396			}
1397			break;
1398		case PR_SIGNALLED:
1399			if (!cflag && (qual_flags[what] & QUAL_SIGNAL)) {
1400				printleader(tcp);
1401				tprintf("--- %s (%s) ---",
1402					signame(what), strsignal(what));
1403				printtrailer(tcp);
1404			}
1405			break;
1406		case PR_FAULTED:
1407			if (!cflag && (qual_flags[what] & QUAL_FAULT)) {
1408				printleader(tcp);
1409				tprintf("=== FAULT %d ===", what);
1410				printtrailer(tcp);
1411			}
1412			break;
1413		default:
1414			fprintf(stderr, "odd stop %d\n", tcp->status.PR_WHY);
1415			exit(1);
1416			break;
1417		}
1418		arg = 0;
1419		if (IOCTL (tcp->pfd, PIOCRUN, &arg) < 0) {
1420			perror("PIOCRUN");
1421			exit(1);
1422		}
1423	}
1424	return 0;
1425}
1426
1427#else /* !SVR4 */
1428
1429static int
1430trace()
1431{
1432	int pid;
1433	int wait_errno;
1434	int status;
1435	struct tcb *tcp;
1436#ifdef LINUX
1437	struct rusage ru;
1438#endif /* LINUX */
1439
1440	while (nprocs != 0) {
1441		if (interactive)
1442			sigprocmask(SIG_SETMASK, &empty_set, NULL);
1443#ifdef LINUX
1444		pid = wait4(-1, &status, 0, cflag ? &ru : NULL);
1445#endif /* LINUX */
1446#ifdef SUNOS4
1447		pid = wait(&status);
1448#endif /* SUNOS4 */
1449		wait_errno = errno;
1450		if (interactive)
1451			sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1452
1453		if (interrupted)
1454			return 0;
1455
1456		if (pid == -1) {
1457			switch (wait_errno) {
1458			case EINTR:
1459				continue;
1460			case ECHILD:
1461				/*
1462				 * We would like to verify this case
1463				 * but sometimes a race in Solbourne's
1464				 * version of SunOS sometimes reports
1465				 * ECHILD before sending us SIGCHILD.
1466				 */
1467#if 0
1468				if (nprocs == 0)
1469					return 0;
1470				fprintf(stderr, "strace: proc miscount\n");
1471				exit(1);
1472#endif
1473				return 0;
1474			default:
1475				errno = wait_errno;
1476				perror("strace: wait");
1477				return -1;
1478			}
1479		}
1480		if (debug)
1481			fprintf(stderr, " [wait(%#x) = %u]\n", status, pid);
1482
1483		/* Look up `pid' in our table. */
1484		if ((tcp = pid2tcb(pid)) == NULL) {
1485#if 1 /* XXX davidm */
1486			struct tcb *tcpchild;
1487
1488			if ((tcpchild = alloctcb(pid)) == NULL) {
1489				fprintf(stderr, " [tcb table full]\n");
1490				kill(pid, SIGKILL); /* XXX */
1491				return 0;
1492			}
1493			tcpchild->flags |= TCB_ATTACHED;
1494			newoutf(tcpchild);
1495			tcp->nchildren++;
1496			if (!qflag)
1497				fprintf(stderr, "Process %d attached\n", pid);
1498#else
1499			fprintf(stderr, "unknown pid: %u\n", pid);
1500			if (WIFSTOPPED(status))
1501				ptrace(PTRACE_CONT, pid, (char *) 1, 0);
1502			exit(1);
1503#endif
1504		}
1505		/* set current output file */
1506		outf = tcp->outf;
1507		if (cflag) {
1508#ifdef LINUX
1509			tv_sub(&tcp->dtime, &ru.ru_stime, &tcp->stime);
1510			tcp->stime = ru.ru_stime;
1511#endif /* !LINUX */
1512		}
1513
1514		if (tcp->flags & TCB_SUSPENDED) {
1515			/*
1516			 * Apparently, doing any ptrace() call on a stopped
1517			 * process, provokes the kernel to report the process
1518			 * status again on a subsequent wait(), even if the
1519			 * process has not been actually restarted.
1520			 * Since we have inspected the arguments of suspended
1521			 * processes we end up here testing for this case.
1522			 */
1523			continue;
1524		}
1525		if (WIFSIGNALED(status)) {
1526			if (!cflag
1527			    && (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)) {
1528				printleader(tcp);
1529				tprintf("+++ killed by %s +++",
1530					signame(WTERMSIG(status)));
1531				printtrailer(tcp);
1532			}
1533			droptcb(tcp);
1534			continue;
1535		}
1536		if (WIFEXITED(status)) {
1537			if (debug)
1538				fprintf(stderr, "pid %u exited\n", pid);
1539			if (tcp->flags & TCB_ATTACHED)
1540				fprintf(stderr,
1541					"PANIC: attached pid %u exited\n",
1542					pid);
1543			droptcb(tcp);
1544			continue;
1545		}
1546		if (!WIFSTOPPED(status)) {
1547			fprintf(stderr, "PANIC: pid %u not stopped\n", pid);
1548			droptcb(tcp);
1549			continue;
1550		}
1551		if (debug)
1552			fprintf(stderr, "pid %u stopped, [%s]\n",
1553				pid, signame(WSTOPSIG(status)));
1554
1555		if (tcp->flags & TCB_STARTUP) {
1556			/*
1557			 * This flag is there to keep us in sync.
1558			 * Next time this process stops it should
1559			 * really be entering a system call.
1560			 */
1561			tcp->flags &= ~TCB_STARTUP;
1562			if (tcp->flags & TCB_ATTACHED) {
1563				/*
1564				 * Interestingly, the process may stop
1565				 * with STOPSIG equal to some other signal
1566				 * than SIGSTOP if we happend to attach
1567				 * just before the process takes a signal.
1568				 */
1569				if (!WIFSTOPPED(status)) {
1570					fprintf(stderr,
1571						"pid %u not stopped\n", pid);
1572					detach(tcp, WSTOPSIG(status));
1573					continue;
1574				}
1575			}
1576			else {
1577#ifdef SUNOS4
1578				/* A child of us stopped at exec */
1579				if (WSTOPSIG(status) == SIGTRAP && followvfork)
1580					fixvfork(tcp);
1581#endif /* SUNOS4 */
1582			}
1583			if (tcp->flags & TCB_BPTSET) {
1584				if (clearbpt(tcp) < 0) /* Pretty fatal */ {
1585					droptcb(tcp);
1586					cleanup();
1587					return -1;
1588				}
1589			}
1590			goto tracing;
1591		}
1592
1593		if (WSTOPSIG(status) != SIGTRAP) {
1594			if (WSTOPSIG(status) == SIGSTOP &&
1595					(tcp->flags & TCB_SIGTRAPPED)) {
1596				/*
1597				 * Trapped attempt to block SIGTRAP
1598				 * Hope we are back in control now.
1599				 */
1600				tcp->flags &= ~(TCB_INSYSCALL | TCB_SIGTRAPPED);
1601				if (ptrace(PTRACE_SYSCALL,
1602						pid, (char *) 1, 0) < 0) {
1603					perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1604					cleanup();
1605					return -1;
1606				}
1607				continue;
1608			}
1609			if (!cflag
1610			    && (qual_flags[WSTOPSIG(status)] & QUAL_SIGNAL)) {
1611				printleader(tcp);
1612				tprintf("--- %s (%s) ---",
1613					signame(WSTOPSIG(status)),
1614					strsignal(WSTOPSIG(status)));
1615				printtrailer(tcp);
1616			}
1617			if ((tcp->flags & TCB_ATTACHED) &&
1618				!sigishandled(tcp, WSTOPSIG(status))) {
1619				detach(tcp, WSTOPSIG(status));
1620				continue;
1621			}
1622			if (ptrace(PTRACE_SYSCALL, pid, (char *) 1,
1623				   WSTOPSIG(status)) < 0) {
1624				perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1625				cleanup();
1626				return -1;
1627			}
1628			tcp->flags &= ~TCB_SUSPENDED;
1629			continue;
1630		}
1631		if (trace_syscall(tcp) < 0) {
1632			if (tcp->flags & TCB_ATTACHED)
1633				detach(tcp, 0);
1634			else {
1635				ptrace(PTRACE_KILL,
1636					tcp->pid, (char *) 1, SIGTERM);
1637				droptcb(tcp);
1638			}
1639			continue;
1640		}
1641		if (tcp->flags & TCB_EXITING) {
1642			if (tcp->flags & TCB_ATTACHED)
1643				detach(tcp, 0);
1644			else if (ptrace(PTRACE_CONT, pid, (char *) 1, 0) < 0) {
1645				perror("strace: ptrace(PTRACE_CONT, ...)");
1646				cleanup();
1647				return -1;
1648			}
1649			continue;
1650		}
1651		if (tcp->flags & TCB_SUSPENDED) {
1652			if (!qflag)
1653				fprintf(stderr, "Process %u suspended\n", pid);
1654			continue;
1655		}
1656	tracing:
1657		if (ptrace(PTRACE_SYSCALL, pid, (char *) 1, 0) < 0) {
1658			perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1659			cleanup();
1660			return -1;
1661		}
1662	}
1663	return 0;
1664}
1665
1666#endif /* !SVR4 */
1667
1668static int curcol;
1669
1670#ifdef __STDC__
1671#include <stdarg.h>
1672#define VA_START(a, b) va_start(a, b)
1673#else
1674#include <varargs.h>
1675#define VA_START(a, b) va_start(a)
1676#endif
1677
1678void
1679#ifdef __STDC__
1680tprintf(const char *fmt, ...)
1681#else
1682tprintf(fmt, va_alist)
1683char *fmt;
1684va_dcl
1685#endif
1686{
1687	va_list args;
1688
1689	VA_START(args, fmt);
1690	if (outf)
1691		curcol += vfprintf(outf, fmt, args);
1692	va_end(args);
1693	return;
1694}
1695
1696void
1697printleader(tcp)
1698struct tcb *tcp;
1699{
1700	if (tcp_last && (!outfname || followfork < 2 || tcp_last == tcp)) {
1701		tcp_last->flags |= TCB_REPRINT;
1702		tprintf(" <unfinished ...>\n");
1703	}
1704	curcol = 0;
1705	if ((followfork == 1 || pflag_seen > 1) && outfname)
1706		tprintf("%-5d ", tcp->pid);
1707	else if (nprocs > 1 && !outfname)
1708		tprintf("[pid %5u] ", tcp->pid);
1709	if (tflag) {
1710		char str[sizeof("HH:MM:SS")];
1711		struct timeval tv, dtv;
1712		static struct timeval otv;
1713
1714		gettimeofday(&tv, NULL);
1715		if (rflag) {
1716			if (otv.tv_sec == 0)
1717				otv = tv;
1718			tv_sub(&dtv, &tv, &otv);
1719			tprintf("%6ld.%06ld ",
1720				(long) dtv.tv_sec, (long) dtv.tv_usec);
1721			otv = tv;
1722		}
1723		else if (tflag > 2) {
1724			tprintf("%ld.%06ld ",
1725				(long) tv.tv_sec, (long) tv.tv_usec);
1726		}
1727		else {
1728			time_t local = tv.tv_sec;
1729			strftime(str, sizeof(str), "%T", localtime(&local));
1730			if (tflag > 1)
1731				tprintf("%s.%06ld ", str, (long) tv.tv_usec);
1732			else
1733				tprintf("%s ", str);
1734		}
1735	}
1736	if (iflag)
1737		printcall(tcp);
1738}
1739
1740void
1741tabto(col)
1742int col;
1743{
1744	if (curcol < col)
1745		tprintf("%*s", col - curcol, "");
1746}
1747
1748void
1749printtrailer(tcp)
1750struct tcb *tcp;
1751{
1752	tprintf("\n");
1753	tcp_last = NULL;
1754}
1755
1756#ifdef HAVE_MP_PROCFS
1757
1758int mp_ioctl (int fd, int cmd, void *arg, int size) {
1759
1760	struct iovec iov[2];
1761	int n = 1;
1762
1763	iov[0].iov_base = &cmd;
1764	iov[0].iov_len = sizeof cmd;
1765	if (arg) {
1766		++n;
1767		iov[1].iov_base = arg;
1768		iov[1].iov_len = size;
1769	}
1770
1771	return writev (fd, iov, n);
1772}
1773
1774#endif
1775