strace.c revision eb8ebdad122a20ecae0ce8e3e60cb71d8e4a7152 
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#include <limits.h>
47
48#if defined(IA64) && defined(LINUX)
49# include <asm/ptrace_offsets.h>
50#endif
51
52#ifdef USE_PROCFS
53#include <poll.h>
54#endif
55
56#ifdef SVR4
57#include <sys/stropts.h>
58#ifdef HAVE_MP_PROCFS
59#ifdef HAVE_SYS_UIO_H
60#include <sys/uio.h>
61#endif
62#endif
63#endif
64
65int debug = 0, followfork = 0, followvfork = 0, interactive = 0;
66int rflag = 0, tflag = 0, dtime = 0, cflag = 0;
67int iflag = 0, xflag = 0, qflag = 0;
68int pflag_seen = 0;
69
70char *username = NULL;
71uid_t run_uid;
72gid_t run_gid;
73
74int acolumn = DEFAULT_ACOLUMN;
75int max_strlen = DEFAULT_STRLEN;
76char *outfname = NULL;
77FILE *outf;
78struct tcb tcbtab[MAX_PROCS];
79int nprocs;
80char *progname;
81extern char version[];
82extern char **environ;
83
84static struct tcb *pid2tcb P((int pid));
85static int trace P((void));
86static void cleanup P((void));
87static void interrupt P((int sig));
88static sigset_t empty_set, blocked_set;
89
90#ifdef HAVE_SIG_ATOMIC_T
91static volatile sig_atomic_t interrupted;
92#else /* !HAVE_SIG_ATOMIC_T */
93#ifdef __STDC__
94static volatile int interrupted;
95#else /* !__STDC__ */
96static int interrupted;
97#endif /* !__STDC__ */
98#endif /* !HAVE_SIG_ATOMIC_T */
99
100#ifdef USE_PROCFS
101
102static struct tcb *pfd2tcb P((int pfd));
103static void reaper P((int sig));
104static void rebuild_pollv P((void));
105struct pollfd pollv[MAX_PROCS];
106
107#ifndef HAVE_POLLABLE_PROCFS
108
109static void proc_poll_open P((void));
110static void proc_poller P((int pfd));
111
112struct proc_pollfd {
113	int fd;
114	int revents;
115	int pid;
116};
117
118static int poller_pid;
119static int proc_poll_pipe[2] = { -1, -1 };
120
121#endif /* !HAVE_POLLABLE_PROCFS */
122
123#ifdef HAVE_MP_PROCFS
124#define POLLWANT	POLLWRNORM
125#else
126#define POLLWANT	POLLPRI
127#endif
128#endif /* USE_PROCFS */
129
130static void
131usage(ofp, exitval)
132FILE *ofp;
133int exitval;
134{
135	fprintf(ofp, "\
136usage: strace [-dffhiqrtttTvVxx] [-a column] [-e expr] ... [-o file]\n\
137              [-p pid] ... [-s strsize] [-u username] [command [arg ...]]\n\
138   or: strace -c [-e expr] ... [-O overhead] [-S sortby] [command [arg ...]]\n\
139-c -- count time, calls, and errors for each syscall and report summary\n\
140-f -- follow forks, -ff -- with output into separate files\n\
141-F -- attempt to follow vforks, -h -- print help message\n\
142-i -- print instruction pointer at time of syscall\n\
143-q -- suppress messages about attaching, detaching, etc.\n\
144-r -- print relative timestamp, -t -- absolute timestamp, -tt -- with usecs\n\
145-T -- print time spent in each syscall, -V -- print version\n\
146-v -- verbose mode: print unabbreviated argv, stat, termio[s], etc. args\n\
147-x -- print non-ascii strings in hex, -xx -- print all strings in hex\n\
148-a column -- alignment COLUMN for printing syscall results (default %d)\n\
149-e expr -- a qualifying expression: option=[!]all or option=[!]val1[,val2]...\n\
150   options: trace, abbrev, verbose, raw, signal, read, or write\n\
151-o file -- send trace output to FILE instead of stderr\n\
152-O overhead -- set overhead for tracing syscalls to OVERHEAD usecs\n\
153-p pid -- trace process with process id PID, may be repeated\n\
154-s strsize -- limit length of print strings to STRSIZE chars (default %d)\n\
155-S sortby -- sort syscall counts by: time, calls, name, nothing (default %s)\n\
156-u username -- run command as username handling setuid and/or setgid\n\
157", DEFAULT_ACOLUMN, DEFAULT_STRLEN, DEFAULT_SORTBY);
158	exit(exitval);
159}
160
161#ifdef SVR4
162#ifdef MIPS
163void
164foobar()
165{
166}
167#endif /* MIPS */
168#endif /* SVR4 */
169
170int
171main(argc, argv)
172int argc;
173char *argv[];
174{
175	extern int optind;
176	extern char *optarg;
177	struct tcb *tcp;
178	int c, pid = 0;
179	struct sigaction sa;
180
181	static char buf[BUFSIZ];
182
183	progname = argv[0];
184	outf = stderr;
185	interactive = 1;
186	qualify("trace=all");
187	qualify("abbrev=all");
188	qualify("verbose=all");
189	qualify("signal=all");
190	set_sortby(DEFAULT_SORTBY);
191	set_personality(DEFAULT_PERSONALITY);
192	while ((c = getopt(argc, argv,
193		"+cdfFhiqrtTvVxa:e:o:O:p:s:S:u:")) != EOF) {
194		switch (c) {
195		case 'c':
196			cflag++;
197			dtime++;
198			break;
199		case 'd':
200			debug++;
201			break;
202		case 'f':
203			followfork++;
204			break;
205		case 'F':
206			followvfork++;
207			break;
208		case 'h':
209			usage(stdout, 0);
210			break;
211		case 'i':
212			iflag++;
213			break;
214		case 'q':
215			qflag++;
216			break;
217		case 'r':
218			rflag++;
219			tflag++;
220			break;
221		case 't':
222			tflag++;
223			break;
224		case 'T':
225			dtime++;
226			break;
227		case 'x':
228			xflag++;
229			break;
230		case 'v':
231			qualify("abbrev=none");
232			break;
233		case 'V':
234			printf("%s\n", version);
235			exit(0);
236			break;
237		case 'a':
238			acolumn = atoi(optarg);
239			break;
240		case 'e':
241			qualify(optarg);
242			break;
243		case 'o':
244			outfname = strdup(optarg);
245			break;
246		case 'O':
247			set_overhead(atoi(optarg));
248			break;
249		case 'p':
250			if ((pid = atoi(optarg)) == 0) {
251				fprintf(stderr, "%s: Invalid process id: %s\n",
252					progname, optarg);
253				break;
254			}
255			if (pid == getpid()) {
256				fprintf(stderr, "%s: I'm sorry, I can't let you do that, Dave.\n", progname);
257				break;
258			}
259			if ((tcp = alloctcb(pid)) == NULL) {
260				fprintf(stderr, "%s: tcb table full, please recompile strace\n",
261					progname);
262				exit(1);
263			}
264			tcp->flags |= TCB_ATTACHED;
265			pflag_seen++;
266			break;
267		case 's':
268			max_strlen = atoi(optarg);
269			break;
270		case 'S':
271			set_sortby(optarg);
272			break;
273		case 'u':
274			username = strdup(optarg);
275			break;
276		default:
277			usage(stderr, 1);
278			break;
279		}
280	}
281
282	/* See if they want to run as another user. */
283	if (username != NULL) {
284		struct passwd *pent;
285
286		if (getuid() != 0 || geteuid() != 0) {
287			fprintf(stderr,
288				"%s: you must be root to use the -u option\n",
289				progname);
290			exit(1);
291		}
292		if ((pent = getpwnam(username)) == NULL) {
293			fprintf(stderr, "%s: cannot find user `%s'\n",
294				progname, optarg);
295			exit(1);
296		}
297		run_uid = pent->pw_uid;
298		run_gid = pent->pw_gid;
299	}
300	else {
301		run_uid = getuid();
302		run_gid = getgid();
303	}
304
305#ifndef SVR4
306	setreuid(geteuid(), getuid());
307#endif
308
309	/* See if they want to pipe the output. */
310	if (outfname && (outfname[0] == '|' || outfname[0] == '!')) {
311		if ((outf = popen(outfname + 1, "w")) == NULL) {
312			fprintf(stderr, "%s: can't popen '%s': %s\n",
313				progname, outfname + 1, strerror(errno));
314			exit(1);
315		}
316		free(outfname);
317		outfname = NULL;
318	}
319
320	/* Check if they want to redirect the output. */
321	if (outfname) {
322		long f;
323
324		if ((outf = fopen(outfname, "w")) == NULL) {
325			fprintf(stderr, "%s: can't fopen '%s': %s\n",
326				progname, outfname, strerror(errno));
327			exit(1);
328		}
329
330		if ((f=fcntl(fileno(outf), F_GETFD)) < 0 ) {
331			perror("failed to get flags for outputfile");
332			exit(1);
333		}
334
335		if (fcntl(fileno(outf), F_SETFD, f|FD_CLOEXEC) < 0 ) {
336			perror("failed to set flags for outputfile");
337			exit(1);
338		}
339	}
340
341#ifndef SVR4
342	setreuid(geteuid(), getuid());
343#endif
344
345	if (!outfname) {
346		qflag = 1;
347		setvbuf(outf, buf, _IOLBF, BUFSIZ);
348	}
349	else if (optind < argc)
350		interactive = 0;
351	else
352		qflag = 1;
353
354	for (c = 0, tcp = tcbtab; c < MAX_PROCS; c++, tcp++) {
355		/* Reinitialize the output since it may have changed. */
356		tcp->outf = outf;
357		if (!(tcp->flags & TCB_INUSE) || !(tcp->flags & TCB_ATTACHED))
358			continue;
359#ifdef USE_PROCFS
360		if (proc_open(tcp, 1) < 0) {
361			fprintf(stderr, "trouble opening proc file\n");
362			droptcb(tcp);
363			continue;
364		}
365#else /* !USE_PROCFS */
366		if (ptrace(PTRACE_ATTACH, tcp->pid, (char *) 1, 0) < 0) {
367			perror("attach: ptrace(PTRACE_ATTACH, ...)");
368			droptcb(tcp);
369			continue;
370		}
371#endif /* !USE_PROCFS */
372		if (!qflag)
373			fprintf(stderr,
374				"Process %u attached - interrupt to quit\n",
375				pid);
376	}
377
378	if (optind < argc) {
379		struct stat statbuf;
380		char *filename;
381		char pathname[MAXPATHLEN];
382
383		filename = argv[optind];
384		if (strchr(filename, '/'))
385			strcpy(pathname, filename);
386#ifdef USE_DEBUGGING_EXEC
387		/*
388		 * Debuggers customarily check the current directory
389		 * first regardless of the path but doing that gives
390		 * security geeks a panic attack.
391		 */
392		else if (stat(filename, &statbuf) == 0)
393			strcpy(pathname, filename);
394#endif /* USE_DEBUGGING_EXEC */
395		else {
396			char *path;
397			int m, n, len;
398
399			for (path = getenv("PATH"); path && *path; path += m) {
400				if (strchr(path, ':')) {
401					n = strchr(path, ':') - path;
402					m = n + 1;
403				}
404				else
405					m = n = strlen(path);
406				if (n == 0) {
407					getcwd(pathname, MAXPATHLEN);
408					len = strlen(pathname);
409				}
410				else {
411					strncpy(pathname, path, n);
412					len = n;
413				}
414				if (len && pathname[len - 1] != '/')
415					pathname[len++] = '/';
416				strcpy(pathname + len, filename);
417				if (stat(pathname, &statbuf) == 0)
418					break;
419			}
420		}
421		if (stat(pathname, &statbuf) < 0) {
422			fprintf(stderr, "%s: %s: command not found\n",
423				progname, filename);
424			exit(1);
425		}
426		switch (pid = fork()) {
427		case -1:
428			perror("strace: fork");
429			cleanup();
430			exit(1);
431			break;
432		case 0: {
433#ifdef USE_PROCFS
434		        if (outf != stderr) close (fileno (outf));
435#ifdef MIPS
436			/* Kludge for SGI, see proc_open for details. */
437			sa.sa_handler = foobar;
438			sa.sa_flags = 0;
439			sigemptyset(&sa.sa_mask);
440			sigaction(SIGINT, &sa, NULL);
441#endif /* MIPS */
442#ifndef FREEBSD
443			pause();
444#else /* FREEBSD */
445			kill(getpid(), SIGSTOP); /* stop HERE */
446#endif /* FREEBSD */
447#else /* !USE_PROCFS */
448			if (outf!=stderr)
449				close(fileno (outf));
450
451			if (ptrace(PTRACE_TRACEME, 0, (char *) 1, 0) < 0) {
452				perror("strace: ptrace(PTRACE_TRACEME, ...)");
453				return -1;
454			}
455			if (debug)
456				kill(getpid(), SIGSTOP);
457
458			if (username != NULL || geteuid() == 0) {
459				uid_t run_euid = run_uid;
460				gid_t run_egid = run_gid;
461
462				if (statbuf.st_mode & S_ISUID)
463					run_euid = statbuf.st_uid;
464				if (statbuf.st_mode & S_ISGID)
465					run_egid = statbuf.st_gid;
466
467				/*
468				 * It is important to set groups before we
469				 * lose privileges on setuid.
470				 */
471				if (username != NULL) {
472					if (initgroups(username, run_gid) < 0) {
473						perror("initgroups");
474						exit(1);
475					}
476					if (setregid(run_gid, run_egid) < 0) {
477						perror("setregid");
478						exit(1);
479					}
480					if (setreuid(run_uid, run_euid) < 0) {
481						perror("setreuid");
482						exit(1);
483					}
484				}
485			}
486			else
487				setreuid(run_uid, run_uid);
488#endif /* !USE_PROCFS */
489
490			execv(pathname, &argv[optind]);
491			perror("strace: exec");
492			_exit(1);
493			break;
494		}
495		default:
496			if ((tcp = alloctcb(pid)) == NULL) {
497				fprintf(stderr, "tcb table full\n");
498				cleanup();
499				exit(1);
500			}
501#ifdef USE_PROCFS
502			if (proc_open(tcp, 0) < 0) {
503				fprintf(stderr, "trouble opening proc file\n");
504				cleanup();
505				exit(1);
506			}
507#endif /* USE_PROCFS */
508#ifndef USE_PROCFS
509			fake_execve(tcp, pathname, &argv[optind], environ);
510#endif /* !USE_PROCFS */
511			break;
512		}
513	}
514	else if (pflag_seen == 0)
515		usage(stderr, 1);
516
517	sigemptyset(&empty_set);
518	sigemptyset(&blocked_set);
519	sa.sa_handler = SIG_IGN;
520	sigemptyset(&sa.sa_mask);
521	sa.sa_flags = 0;
522	sigaction(SIGTTOU, &sa, NULL);
523	sigaction(SIGTTIN, &sa, NULL);
524	if (interactive) {
525		sigaddset(&blocked_set, SIGHUP);
526		sigaddset(&blocked_set, SIGINT);
527		sigaddset(&blocked_set, SIGQUIT);
528		sigaddset(&blocked_set, SIGPIPE);
529		sigaddset(&blocked_set, SIGTERM);
530		sa.sa_handler = interrupt;
531#ifdef SUNOS4
532		/* POSIX signals on sunos4.1 are a little broken. */
533		sa.sa_flags = SA_INTERRUPT;
534#endif /* SUNOS4 */
535	}
536	sigaction(SIGHUP, &sa, NULL);
537	sigaction(SIGINT, &sa, NULL);
538	sigaction(SIGQUIT, &sa, NULL);
539	sigaction(SIGPIPE, &sa, NULL);
540	sigaction(SIGTERM, &sa, NULL);
541#ifdef USE_PROCFS
542	sa.sa_handler = reaper;
543	sigaction(SIGCHLD, &sa, NULL);
544#endif /* USE_PROCFS */
545
546	if (trace() < 0)
547		exit(1);
548	cleanup();
549	exit(0);
550}
551
552void
553newoutf(tcp)
554struct tcb *tcp;
555{
556	char name[MAXPATHLEN];
557	FILE *fp;
558
559	if (outfname && followfork > 1) {
560		sprintf(name, "%s.%u", outfname, tcp->pid);
561#ifndef SVR4
562		setreuid(geteuid(), getuid());
563#endif
564		fp = fopen(name, "w");
565#ifndef SVR4
566		setreuid(geteuid(), getuid());
567#endif
568		if (fp == NULL) {
569			perror("fopen");
570			return;
571		}
572		tcp->outf = fp;
573	}
574	return;
575}
576
577struct tcb *
578alloctcb(pid)
579int pid;
580{
581	int i;
582	struct tcb *tcp;
583
584	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
585		if ((tcp->flags & TCB_INUSE) == 0) {
586			tcp->pid = pid;
587			tcp->parent = NULL;
588			tcp->nchildren = 0;
589			tcp->flags = TCB_INUSE | TCB_STARTUP;
590			tcp->outf = outf; /* Initialise to current out file */
591			tcp->stime.tv_sec = 0;
592			tcp->stime.tv_usec = 0;
593			tcp->pfd = -1;
594			nprocs++;
595			return tcp;
596		}
597	}
598	return NULL;
599}
600
601#ifdef USE_PROCFS
602int
603proc_open(tcp, attaching)
604struct tcb *tcp;
605int attaching;
606{
607	char proc[32];
608	long arg;
609#ifdef SVR4
610	int i;
611	sysset_t syscalls;
612	sigset_t signals;
613	fltset_t faults;
614#endif
615#ifndef HAVE_POLLABLE_PROCFS
616	static int last_pfd;
617#endif
618
619#ifdef HAVE_MP_PROCFS
620	/* Open the process pseudo-files in /proc. */
621	sprintf(proc, "/proc/%d/ctl", tcp->pid);
622	if ((tcp->pfd = open(proc, O_WRONLY|O_EXCL)) < 0) {
623		perror("strace: open(\"/proc/...\", ...)");
624		return -1;
625	}
626	if ((arg = fcntl(tcp->pfd, F_GETFD)) < 0) {
627		perror("F_GETFD");
628		return -1;
629	}
630	if (fcntl(tcp->pfd, F_SETFD, arg|FD_CLOEXEC) < 0) {
631		perror("F_SETFD");
632		return -1;
633	}
634	sprintf(proc, "/proc/%d/status", tcp->pid);
635	if ((tcp->pfd_stat = open(proc, O_RDONLY|O_EXCL)) < 0) {
636		perror("strace: open(\"/proc/...\", ...)");
637		return -1;
638	}
639	if ((arg = fcntl(tcp->pfd_stat, F_GETFD)) < 0) {
640		perror("F_GETFD");
641		return -1;
642	}
643	if (fcntl(tcp->pfd_stat, F_SETFD, arg|FD_CLOEXEC) < 0) {
644		perror("F_SETFD");
645		return -1;
646	}
647	sprintf(proc, "/proc/%d/as", tcp->pid);
648	if ((tcp->pfd_as = open(proc, O_RDONLY|O_EXCL)) < 0) {
649		perror("strace: open(\"/proc/...\", ...)");
650		return -1;
651	}
652	if ((arg = fcntl(tcp->pfd_as, F_GETFD)) < 0) {
653		perror("F_GETFD");
654		return -1;
655	}
656	if (fcntl(tcp->pfd_as, F_SETFD, arg|FD_CLOEXEC) < 0) {
657		perror("F_SETFD");
658		return -1;
659	}
660#else
661	/* Open the process pseudo-file in /proc. */
662#ifndef FREEBSD
663	sprintf(proc, "/proc/%d", tcp->pid);
664	if ((tcp->pfd = open(proc, O_RDWR|O_EXCL)) < 0) {
665#else /* FREEBSD */
666	sprintf(proc, "/proc/%d/mem", tcp->pid);
667	if ((tcp->pfd = open(proc, O_RDWR)) < 0) {
668#endif /* FREEBSD */
669		perror("strace: open(\"/proc/...\", ...)");
670		return -1;
671	}
672	if ((arg = fcntl(tcp->pfd, F_GETFD)) < 0) {
673		perror("F_GETFD");
674		return -1;
675	}
676	if (fcntl(tcp->pfd, F_SETFD, arg|FD_CLOEXEC) < 0) {
677		perror("F_SETFD");
678		return -1;
679	}
680#endif
681#ifdef FREEBSD
682	sprintf(proc, "/proc/%d/regs", tcp->pid);
683	if ((tcp->pfd_reg = open(proc, O_RDONLY)) < 0) {
684		perror("strace: open(\"/proc/.../regs\", ...)");
685		return -1;
686	}
687	if (cflag) {
688		sprintf(proc, "/proc/%d/status", tcp->pid);
689		if ((tcp->pfd_status = open(proc, O_RDONLY)) < 0) {
690			perror("strace: open(\"/proc/.../status\", ...)");
691			return -1;
692		}
693	} else
694		tcp->pfd_status = -1;
695#endif /* FREEBSD */
696	rebuild_pollv();
697	if (!attaching) {
698		/*
699		 * Wait for the child to pause.  Because of a race
700		 * condition we have to poll for the event.
701		 */
702		for (;;) {
703			if (IOCTL_STATUS (tcp) < 0) {
704				perror("strace: PIOCSTATUS");
705				return -1;
706			}
707			if (tcp->status.PR_FLAGS & PR_ASLEEP)
708			    break;
709		}
710	}
711#ifndef FREEBSD
712	/* Stop the process so that we own the stop. */
713	if (IOCTL(tcp->pfd, PIOCSTOP, (char *)NULL) < 0) {
714		perror("strace: PIOCSTOP");
715		return -1;
716	}
717#endif
718#ifdef PIOCSET
719	/* Set Run-on-Last-Close. */
720	arg = PR_RLC;
721	if (IOCTL(tcp->pfd, PIOCSET, &arg) < 0) {
722		perror("PIOCSET PR_RLC");
723		return -1;
724	}
725	/* Set or Reset Inherit-on-Fork. */
726	arg = PR_FORK;
727	if (IOCTL(tcp->pfd, followfork ? PIOCSET : PIOCRESET, &arg) < 0) {
728		perror("PIOC{SET,RESET} PR_FORK");
729		return -1;
730	}
731#else  /* !PIOCSET */
732#ifndef FREEBSD
733	if (ioctl(tcp->pfd, PIOCSRLC) < 0) {
734		perror("PIOCSRLC");
735		return -1;
736	}
737	if (ioctl(tcp->pfd, followfork ? PIOCSFORK : PIOCRFORK) < 0) {
738		perror("PIOC{S,R}FORK");
739		return -1;
740	}
741#else /* FREEBSD */
742	/* just unset the PF_LINGER flag for the Run-on-Last-Close. */
743	if (ioctl(tcp->pfd, PIOCGFL, &arg) < 0) {
744	        perror("PIOCGFL");
745	        return -1;
746	}
747	arg &= ~PF_LINGER;
748	if (ioctl(tcp->pfd, PIOCSFL, arg) < 0) {
749	        perror("PIOCSFL");
750	        return -1;
751	}
752#endif /* FREEBSD */
753#endif /* !PIOCSET */
754#ifndef FREEBSD
755	/* Enable all syscall entries we care about. */
756	premptyset(&syscalls);
757	for (i = 1; i < MAX_QUALS; ++i) {
758		if (i > (sizeof syscalls) * CHAR_BIT) break;
759		if (qual_flags [i] & QUAL_TRACE) praddset (&syscalls, i);
760	}
761	praddset (&syscalls, SYS_execve);
762	if (followfork) {
763		praddset (&syscalls, SYS_fork);
764#ifdef SYS_forkall
765		praddset (&syscalls, SYS_forkall);
766#endif
767#ifdef SYS_fork1
768		praddset (&syscalls, SYS_fork1);
769#endif
770#ifdef SYS_rfork1
771		praddset (&syscalls, SYS_rfork1);
772#endif
773#ifdef SYS_rforkall
774		praddset (&syscalls, SYS_rforkall);
775#endif
776	}
777	if (IOCTL(tcp->pfd, PIOCSENTRY, &syscalls) < 0) {
778		perror("PIOCSENTRY");
779		return -1;
780	}
781	/* Enable the syscall exits. */
782	if (IOCTL(tcp->pfd, PIOCSEXIT, &syscalls) < 0) {
783		perror("PIOSEXIT");
784		return -1;
785	}
786	/* Enable signals we care about. */
787	premptyset(&signals);
788	for (i = 1; i < MAX_QUALS; ++i) {
789		if (i > (sizeof signals) * CHAR_BIT) break;
790		if (qual_flags [i] & QUAL_SIGNAL) praddset (&signals, i);
791	}
792	if (IOCTL(tcp->pfd, PIOCSTRACE, &signals) < 0) {
793		perror("PIOCSTRACE");
794		return -1;
795	}
796	/* Enable faults we care about */
797	premptyset(&faults);
798	for (i = 1; i < MAX_QUALS; ++i) {
799		if (i > (sizeof faults) * CHAR_BIT) break;
800		if (qual_flags [i] & QUAL_FAULT) praddset (&faults, i);
801	}
802	if (IOCTL(tcp->pfd, PIOCSFAULT, &faults) < 0) {
803		perror("PIOCSFAULT");
804		return -1;
805	}
806#else /* FREEBSD */
807	/* set events flags. */
808	arg = S_SIG | S_SCE | S_SCX ;
809	if(ioctl(tcp->pfd, PIOCBIS, arg) < 0) {
810		perror("PIOCBIS");
811		return -1;
812	}
813#endif /* FREEBSD */
814	if (!attaching) {
815#ifdef MIPS
816		/*
817		 * The SGI PRSABORT doesn't work for pause() so
818		 * we send it a caught signal to wake it up.
819		 */
820		kill(tcp->pid, SIGINT);
821#else /* !MIPS */
822#ifdef PRSABORT
823		/* The child is in a pause(), abort it. */
824		arg = PRSABORT;
825		if (IOCTL (tcp->pfd, PIOCRUN, &arg) < 0) {
826			perror("PIOCRUN");
827			return -1;
828		}
829#endif
830#endif /* !MIPS*/
831#ifdef FREEBSD
832		/* wake up the child if it received the SIGSTOP */
833		kill(tcp->pid, SIGCONT);
834#endif
835		for (;;) {
836			/* Wait for the child to do something. */
837			if (IOCTL_WSTOP (tcp) < 0) {
838				perror("PIOCWSTOP");
839				return -1;
840			}
841			if (tcp->status.PR_WHY == PR_SYSENTRY) {
842				tcp->flags &= ~TCB_INSYSCALL;
843				get_scno(tcp);
844				if (tcp->scno == SYS_execve)
845					break;
846			}
847			/* Set it running: maybe execve will be next. */
848#ifndef FREEBSD
849			arg = 0;
850			if (IOCTL(tcp->pfd, PIOCRUN, &arg) < 0) {
851#else /* FREEBSD */
852			if (IOCTL(tcp->pfd, PIOCRUN, 0) < 0) {
853#endif /* FREEBSD */
854				perror("PIOCRUN");
855				return -1;
856			}
857#ifdef FREEBSD
858			/* handle the case where we "opened" the child before
859			   it did the kill -STOP */
860			if (tcp->status.PR_WHY == PR_SIGNALLED &&
861			    tcp->status.PR_WHAT == SIGSTOP)
862			        kill(tcp->pid, SIGCONT);
863#endif
864		}
865#ifndef FREEBSD
866	}
867#else /* FREEBSD */
868	} else {
869		if (attaching < 2) {
870			/* We are attaching to an already running process.
871			 * Try to figure out the state of the process in syscalls,
872			 * to handle the first event well.
873			 * This is done by having a look at the "wchan" property of the
874			 * process, which tells where it is stopped (if it is). */
875			FILE * status;
876			char wchan[20]; /* should be enough */
877
878			sprintf(proc, "/proc/%d/status", tcp->pid);
879			status = fopen(proc, "r");
880			if (status &&
881			    (fscanf(status, "%*s %*d %*d %*d %*d %*d,%*d %*s %*d,%*d"
882				    "%*d,%*d %*d,%*d %19s", wchan) == 1) &&
883			    strcmp(wchan, "nochan") && strcmp(wchan, "spread") &&
884			    strcmp(wchan, "stopevent")) {
885				/* The process is asleep in the middle of a syscall.
886				   Fake the syscall entry event */
887				tcp->flags &= ~(TCB_INSYSCALL|TCB_STARTUP);
888				tcp->status.PR_WHY = PR_SYSENTRY;
889				trace_syscall(tcp);
890			}
891			if (status)
892				fclose(status);
893		} /* otherwise it's a fork being followed */
894	}
895#endif /* FREEBSD */
896#ifndef HAVE_POLLABLE_PROCFS
897	if (proc_poll_pipe[0] != -1)
898		proc_poller(tcp->pfd);
899	else if (nprocs > 1) {
900		proc_poll_open();
901		proc_poller(last_pfd);
902		proc_poller(tcp->pfd);
903	}
904	last_pfd = tcp->pfd;
905#endif /* !HAVE_POLLABLE_PROCFS */
906	return 0;
907}
908
909#endif /* USE_PROCFS */
910
911static struct tcb *
912pid2tcb(pid)
913int pid;
914{
915	int i;
916	struct tcb *tcp;
917
918	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
919		if (pid && tcp->pid != pid)
920			continue;
921		if (tcp->flags & TCB_INUSE)
922			return tcp;
923	}
924	return NULL;
925}
926
927#ifdef USE_PROCFS
928
929static struct tcb *
930pfd2tcb(pfd)
931int pfd;
932{
933	int i;
934	struct tcb *tcp;
935
936	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
937		if (tcp->pfd != pfd)
938			continue;
939		if (tcp->flags & TCB_INUSE)
940			return tcp;
941	}
942	return NULL;
943}
944
945#endif /* USE_PROCFS */
946
947void
948droptcb(tcp)
949struct tcb *tcp;
950{
951	if (tcp->pid == 0)
952		return;
953	nprocs--;
954	tcp->pid = 0;
955	tcp->flags = 0;
956
957	if (tcp->pfd != -1) {
958		close(tcp->pfd);
959		tcp->pfd = -1;
960#ifdef FREEBSD
961		if (tcp->pfd_reg != -1) {
962		        close(tcp->pfd_reg);
963		        tcp->pfd_reg = -1;
964		}
965		if (tcp->pfd_status != -1) {
966			close(tcp->pfd_status);
967			tcp->pfd_status = -1;
968		}
969#endif /* !FREEBSD */
970#ifdef USE_PROCFS
971		rebuild_pollv();
972#endif
973	}
974	if (tcp->parent != NULL) {
975		tcp->parent->nchildren--;
976		tcp->parent = NULL;
977	}
978
979	if (outfname && tcp->outf)
980		fclose(tcp->outf);
981
982	tcp->outf = 0;
983}
984
985#ifndef USE_PROCFS
986
987static int
988resume(tcp)
989struct tcb *tcp;
990{
991	if (tcp == NULL)
992		return -1;
993
994	if (!(tcp->flags & TCB_SUSPENDED)) {
995		fprintf(stderr, "PANIC: pid %u not suspended\n", tcp->pid);
996		return -1;
997	}
998	tcp->flags &= ~TCB_SUSPENDED;
999
1000	if (ptrace(PTRACE_SYSCALL, tcp->pid, (char *) 1, 0) < 0) {
1001		perror("resume: ptrace(PTRACE_SYSCALL, ...)");
1002		return -1;
1003	}
1004
1005	if (!qflag)
1006		fprintf(stderr, "Process %u resumed\n", tcp->pid);
1007	return 0;
1008}
1009
1010#endif /* !USE_PROCFS */
1011
1012/* detach traced process; continue with sig */
1013
1014static int
1015detach(tcp, sig)
1016struct tcb *tcp;
1017int sig;
1018{
1019	int error = 0;
1020#ifdef LINUX
1021	int status;
1022#endif
1023
1024	if (tcp->flags & TCB_BPTSET)
1025		sig = SIGKILL;
1026
1027#ifdef LINUX
1028	/*
1029	 * Linux wrongly insists the child be stopped
1030	 * before detaching.  Arghh.  We go through hoops
1031	 * to make a clean break of things.
1032	 */
1033#if defined(SPARC)
1034#undef PTRACE_DETACH
1035#define PTRACE_DETACH PTRACE_SUNDETACH
1036#endif
1037	if ((error = ptrace(PTRACE_DETACH, tcp->pid, (char *) 1, sig)) == 0) {
1038		/* On a clear day, you can see forever. */
1039	}
1040	else if (errno != ESRCH) {
1041		/* Shouldn't happen. */
1042		perror("detach: ptrace(PTRACE_DETACH, ...)");
1043	}
1044	else if (kill(tcp->pid, 0) < 0) {
1045		if (errno != ESRCH)
1046			perror("detach: checking sanity");
1047	}
1048	else if (kill(tcp->pid, SIGSTOP) < 0) {
1049		if (errno != ESRCH)
1050			perror("detach: stopping child");
1051	}
1052	else {
1053		for (;;) {
1054			if (waitpid(tcp->pid, &status, 0) < 0) {
1055				if (errno != ECHILD)
1056					perror("detach: waiting");
1057				break;
1058			}
1059			if (!WIFSTOPPED(status)) {
1060				/* Au revoir, mon ami. */
1061				break;
1062			}
1063			if (WSTOPSIG(status) == SIGSTOP) {
1064				if ((error = ptrace(PTRACE_DETACH,
1065				    tcp->pid, (char *) 1, sig)) < 0) {
1066					if (errno != ESRCH)
1067						perror("detach: ptrace(PTRACE_DETACH, ...)");
1068					/* I died trying. */
1069				}
1070				break;
1071			}
1072			if ((error = ptrace(PTRACE_CONT, tcp->pid, (char *) 1,
1073			    WSTOPSIG(status) == SIGTRAP ?
1074			    0 : WSTOPSIG(status))) < 0) {
1075				if (errno != ESRCH)
1076					perror("detach: ptrace(PTRACE_CONT, ...)");
1077				break;
1078			}
1079		}
1080	}
1081#endif /* LINUX */
1082
1083#if defined(SUNOS4)
1084	/* PTRACE_DETACH won't respect `sig' argument, so we post it here. */
1085	if (sig && kill(tcp->pid, sig) < 0)
1086		perror("detach: kill");
1087	sig = 0;
1088	if ((error = ptrace(PTRACE_DETACH, tcp->pid, (char *) 1, sig)) < 0)
1089		perror("detach: ptrace(PTRACE_DETACH, ...)");
1090#endif /* SUNOS4 */
1091
1092#ifndef USE_PROCFS
1093	if (waiting_parent(tcp))
1094		error = resume(tcp->parent);
1095#endif /* !USE_PROCFS */
1096
1097	if (!qflag)
1098		fprintf(stderr, "Process %u detached\n", tcp->pid);
1099
1100	droptcb(tcp);
1101	return error;
1102}
1103
1104#ifdef USE_PROCFS
1105
1106static void
1107reaper(sig)
1108int sig;
1109{
1110	int pid;
1111	int status;
1112
1113	while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
1114#if 0
1115		struct tcb *tcp;
1116
1117		tcp = pid2tcb(pid);
1118		if (tcp)
1119			droptcb(tcp);
1120#endif
1121	}
1122}
1123
1124#endif /* USE_PROCFS */
1125
1126static void
1127cleanup()
1128{
1129	int i;
1130	struct tcb *tcp;
1131
1132	for (i = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
1133		if (!(tcp->flags & TCB_INUSE))
1134			continue;
1135		if (debug)
1136			fprintf(stderr,
1137				"cleanup: looking at pid %u\n", tcp->pid);
1138		if (tcp_last &&
1139		    (!outfname || followfork < 2 || tcp_last == tcp)) {
1140			tprintf(" <unfinished ...>\n");
1141			tcp_last = NULL;
1142		}
1143		if (tcp->flags & TCB_ATTACHED)
1144			detach(tcp, 0);
1145		else {
1146			kill(tcp->pid, SIGCONT);
1147			kill(tcp->pid, SIGTERM);
1148		}
1149	}
1150	if (cflag)
1151		call_summary(outf);
1152}
1153
1154static void
1155interrupt(sig)
1156int sig;
1157{
1158	interrupted = 1;
1159}
1160
1161#ifndef HAVE_STRERROR
1162
1163#ifndef SYS_ERRLIST_DECLARED
1164extern int sys_nerr;
1165extern char *sys_errlist[];
1166#endif /* SYS_ERRLIST_DECLARED */
1167
1168const char *
1169strerror(errno)
1170int errno;
1171{
1172	static char buf[64];
1173
1174	if (errno < 1 || errno >= sys_nerr) {
1175		sprintf(buf, "Unknown error %d", errno);
1176		return buf;
1177	}
1178	return sys_errlist[errno];
1179}
1180
1181#endif /* HAVE_STERRROR */
1182
1183#ifndef HAVE_STRSIGNAL
1184
1185#ifndef SYS_SIGLIST_DECLARED
1186#ifdef HAVE__SYS_SIGLIST
1187	extern char *_sys_siglist[];
1188#else
1189	extern char *sys_siglist[];
1190#endif
1191#endif /* SYS_SIGLIST_DECLARED */
1192
1193const char *
1194strsignal(sig)
1195int sig;
1196{
1197	static char buf[64];
1198
1199	if (sig < 1 || sig >= NSIG) {
1200		sprintf(buf, "Unknown signal %d", sig);
1201		return buf;
1202	}
1203#ifdef HAVE__SYS_SIGLIST
1204	return _sys_siglist[sig];
1205#else
1206	return sys_siglist[sig];
1207#endif
1208}
1209
1210#endif /* HAVE_STRSIGNAL */
1211
1212#ifdef USE_PROCFS
1213
1214static void
1215rebuild_pollv()
1216{
1217	int i, j;
1218	struct tcb *tcp;
1219
1220	for (i = j = 0, tcp = tcbtab; i < MAX_PROCS; i++, tcp++) {
1221		if (!(tcp->flags & TCB_INUSE))
1222			continue;
1223		pollv[j].fd = tcp->pfd;
1224		pollv[j].events = POLLWANT;
1225		j++;
1226	}
1227	if (j != nprocs) {
1228		fprintf(stderr, "strace: proc miscount\n");
1229		exit(1);
1230	}
1231}
1232
1233#ifndef HAVE_POLLABLE_PROCFS
1234
1235static void
1236proc_poll_open()
1237{
1238	int arg;
1239	int i;
1240
1241	if (pipe(proc_poll_pipe) < 0) {
1242		perror("pipe");
1243		exit(1);
1244	}
1245	for (i = 0; i < 2; i++) {
1246		if ((arg = fcntl(proc_poll_pipe[i], F_GETFD)) < 0) {
1247			perror("F_GETFD");
1248			exit(1);
1249		}
1250		if (fcntl(proc_poll_pipe[i], F_SETFD, arg|FD_CLOEXEC) < 0) {
1251			perror("F_SETFD");
1252			exit(1);
1253		}
1254	}
1255}
1256
1257static int
1258proc_poll(pollv, nfds, timeout)
1259struct pollfd *pollv;
1260int nfds;
1261int timeout;
1262{
1263	int i;
1264	int n;
1265	struct proc_pollfd pollinfo;
1266
1267	if ((n = read(proc_poll_pipe[0], &pollinfo, sizeof(pollinfo))) < 0)
1268		return n;
1269	if (n != sizeof(struct proc_pollfd)) {
1270		fprintf(stderr, "panic: short read: %d\n", n);
1271		exit(1);
1272	}
1273	for (i = 0; i < nprocs; i++) {
1274		if (pollv[i].fd == pollinfo.fd)
1275			pollv[i].revents = pollinfo.revents;
1276		else
1277			pollv[i].revents = 0;
1278	}
1279	poller_pid = pollinfo.pid;
1280	return 1;
1281}
1282
1283static void
1284wakeup_handler(sig)
1285int sig;
1286{
1287}
1288
1289static void
1290proc_poller(pfd)
1291int pfd;
1292{
1293	struct proc_pollfd pollinfo;
1294	struct sigaction sa;
1295	sigset_t blocked_set, empty_set;
1296	int i;
1297	int n;
1298	struct rlimit rl;
1299#ifdef FREEBSD
1300	struct procfs_status pfs;
1301#endif /* FREEBSD */
1302
1303	switch (fork()) {
1304	case -1:
1305		perror("fork");
1306		_exit(0);
1307	case 0:
1308		break;
1309	default:
1310		return;
1311	}
1312
1313	sa.sa_handler = interactive ? SIG_DFL : SIG_IGN;
1314	sa.sa_flags = 0;
1315	sigemptyset(&sa.sa_mask);
1316	sigaction(SIGHUP, &sa, NULL);
1317	sigaction(SIGINT, &sa, NULL);
1318	sigaction(SIGQUIT, &sa, NULL);
1319	sigaction(SIGPIPE, &sa, NULL);
1320	sigaction(SIGTERM, &sa, NULL);
1321	sa.sa_handler = wakeup_handler;
1322	sigaction(SIGUSR1, &sa, NULL);
1323	sigemptyset(&blocked_set);
1324	sigaddset(&blocked_set, SIGUSR1);
1325	sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1326	sigemptyset(&empty_set);
1327
1328	if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
1329		perror("getrlimit(RLIMIT_NOFILE, ...)");
1330		_exit(0);
1331	}
1332	n = rl.rlim_cur;
1333	for (i = 0; i < n; i++) {
1334		if (i != pfd && i != proc_poll_pipe[1])
1335			close(i);
1336	}
1337
1338	pollinfo.fd = pfd;
1339	pollinfo.pid = getpid();
1340	for (;;) {
1341#ifndef FREEBSD
1342	        if (ioctl(pfd, PIOCWSTOP, NULL) < 0)
1343#else /* FREEBSD */
1344	        if (ioctl(pfd, PIOCWSTOP, &pfs) < 0)
1345#endif /* FREEBSD */
1346		{
1347			switch (errno) {
1348			case EINTR:
1349				continue;
1350			case EBADF:
1351				pollinfo.revents = POLLERR;
1352				break;
1353			case ENOENT:
1354				pollinfo.revents = POLLHUP;
1355				break;
1356			default:
1357				perror("proc_poller: PIOCWSTOP");
1358			}
1359			write(proc_poll_pipe[1], &pollinfo, sizeof(pollinfo));
1360			_exit(0);
1361		}
1362		pollinfo.revents = POLLWANT;
1363		write(proc_poll_pipe[1], &pollinfo, sizeof(pollinfo));
1364		sigsuspend(&empty_set);
1365	}
1366}
1367
1368#endif /* !HAVE_POLLABLE_PROCFS */
1369
1370static int
1371choose_pfd()
1372{
1373	int i, j;
1374	struct tcb *tcp;
1375
1376	static int last;
1377
1378	if (followfork < 2 &&
1379	    last < nprocs && (pollv[last].revents & POLLWANT)) {
1380		/*
1381		 * The previous process is ready to run again.  We'll
1382		 * let it do so if it is currently in a syscall.  This
1383		 * heuristic improves the readability of the trace.
1384		 */
1385		tcp = pfd2tcb(pollv[last].fd);
1386		if (tcp && (tcp->flags & TCB_INSYSCALL))
1387			return pollv[last].fd;
1388	}
1389
1390	for (i = 0; i < nprocs; i++) {
1391		/* Let competing children run round robin. */
1392		j = (i + last + 1) % nprocs;
1393		if (pollv[j].revents & (POLLHUP | POLLERR)) {
1394			tcp = pfd2tcb(pollv[j].fd);
1395			if (!tcp) {
1396				fprintf(stderr, "strace: lost proc\n");
1397				exit(1);
1398			}
1399			droptcb(tcp);
1400			return -1;
1401		}
1402		if (pollv[j].revents & POLLWANT) {
1403			last = j;
1404			return pollv[j].fd;
1405		}
1406	}
1407	fprintf(stderr, "strace: nothing ready\n");
1408	exit(1);
1409}
1410
1411static int
1412trace()
1413{
1414#ifdef POLL_HACK
1415	struct tcb *in_syscall;
1416#endif
1417	struct tcb *tcp;
1418	int pfd;
1419	int what;
1420	int ioctl_result = 0, ioctl_errno = 0;
1421	long arg;
1422
1423	for (;;) {
1424		if (interactive)
1425			sigprocmask(SIG_SETMASK, &empty_set, NULL);
1426
1427		if (nprocs == 0)
1428			break;
1429
1430		switch (nprocs) {
1431		case 1:
1432#ifndef HAVE_POLLABLE_PROCFS
1433			if (proc_poll_pipe[0] == -1) {
1434#endif
1435				tcp = pid2tcb(0);
1436				if (!tcp)
1437					continue;
1438				pfd = tcp->pfd;
1439				if (pfd == -1)
1440					continue;
1441				break;
1442#ifndef HAVE_POLLABLE_PROCFS
1443			}
1444			/* fall through ... */
1445#endif /* !HAVE_POLLABLE_PROCFS */
1446		default:
1447#ifdef HAVE_POLLABLE_PROCFS
1448#ifdef POLL_HACK
1449		        /* On some systems (e.g. UnixWare) we get too much ugly
1450			   "unfinished..." stuff when multiple proceses are in
1451			   syscalls.  Here's a nasty hack */
1452
1453			if (in_syscall) {
1454				struct pollfd pv;
1455				tcp = in_syscall;
1456				in_syscall = NULL;
1457				pv.fd = tcp->pfd;
1458				pv.events = POLLWANT;
1459				if ((what = poll (&pv, 1, 1)) < 0) {
1460					if (interrupted)
1461						return 0;
1462					continue;
1463				}
1464				else if (what == 1 && pv.revents & POLLWANT) {
1465					goto FOUND;
1466				}
1467			}
1468#endif
1469
1470			if (poll(pollv, nprocs, INFTIM) < 0) {
1471				if (interrupted)
1472					return 0;
1473				continue;
1474			}
1475#else /* !HAVE_POLLABLE_PROCFS */
1476			if (proc_poll(pollv, nprocs, INFTIM) < 0) {
1477				if (interrupted)
1478					return 0;
1479				continue;
1480			}
1481#endif /* !HAVE_POLLABLE_PROCFS */
1482			pfd = choose_pfd();
1483			if (pfd == -1)
1484				continue;
1485			break;
1486		}
1487
1488		/* Look up `pfd' in our table. */
1489		if ((tcp = pfd2tcb(pfd)) == NULL) {
1490			fprintf(stderr, "unknown pfd: %u\n", pfd);
1491			exit(1);
1492		}
1493	FOUND:
1494		/* Get the status of the process. */
1495		if (!interrupted) {
1496#ifndef FREEBSD
1497			ioctl_result = IOCTL_WSTOP (tcp);
1498#else /* FREEBSD */
1499			/* Thanks to some scheduling mystery, the first poller
1500			   sometimes waits for the already processed end of fork
1501			   event. Doing a non blocking poll here solves the problem. */
1502			if (proc_poll_pipe[0] != -1)
1503				ioctl_result = IOCTL_STATUS (tcp);
1504			else
1505			  	ioctl_result = IOCTL_WSTOP (tcp);
1506#endif /* FREEBSD */
1507			ioctl_errno = errno;
1508#ifndef HAVE_POLLABLE_PROCFS
1509			if (proc_poll_pipe[0] != -1) {
1510				if (ioctl_result < 0)
1511					kill(poller_pid, SIGKILL);
1512				else
1513					kill(poller_pid, SIGUSR1);
1514			}
1515#endif /* !HAVE_POLLABLE_PROCFS */
1516		}
1517		if (interrupted)
1518			return 0;
1519
1520		if (interactive)
1521			sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1522
1523		if (ioctl_result < 0) {
1524			/* Find out what happened if it failed. */
1525			switch (ioctl_errno) {
1526			case EINTR:
1527			case EBADF:
1528				continue;
1529#ifdef FREEBSD
1530			case ENOTTY:
1531#endif
1532			case ENOENT:
1533				droptcb(tcp);
1534				continue;
1535			default:
1536				perror("PIOCWSTOP");
1537				exit(1);
1538			}
1539		}
1540
1541#ifdef FREEBSD
1542		if ((tcp->flags & TCB_STARTUP) && (tcp->status.PR_WHY == PR_SYSEXIT)) {
1543			/* discard first event for a syscall we never entered */
1544			IOCTL (tcp->pfd, PIOCRUN, 0);
1545			continue;
1546		}
1547#endif
1548
1549		/* clear the just started flag */
1550		tcp->flags &= ~TCB_STARTUP;
1551
1552		/* set current output file */
1553		outf = tcp->outf;
1554
1555		if (cflag) {
1556			struct timeval stime;
1557#ifdef FREEBSD
1558			char buf[1024];
1559			int len;
1560
1561			if ((len = pread(tcp->pfd_status, buf, sizeof(buf) - 1, 0)) > 0) {
1562				buf[len] = '\0';
1563				sscanf(buf,
1564				       "%*s %*d %*d %*d %*d %*d,%*d %*s %*d,%*d %*d,%*d %ld,%ld",
1565				       &stime.tv_sec, &stime.tv_usec);
1566			} else
1567				stime.tv_sec = stime.tv_usec = 0;
1568#else /* !FREEBSD */
1569			stime.tv_sec = tcp->status.pr_stime.tv_sec;
1570			stime.tv_usec = tcp->status.pr_stime.tv_nsec/1000;
1571#endif /* !FREEBSD */
1572			tv_sub(&tcp->dtime, &stime, &tcp->stime);
1573			tcp->stime = stime;
1574		}
1575		what = tcp->status.PR_WHAT;
1576		switch (tcp->status.PR_WHY) {
1577#ifndef FREEBSD
1578		case PR_REQUESTED:
1579			if (tcp->status.PR_FLAGS & PR_ASLEEP) {
1580				tcp->status.PR_WHY = PR_SYSENTRY;
1581				if (trace_syscall(tcp) < 0) {
1582					fprintf(stderr, "syscall trouble\n");
1583					exit(1);
1584				}
1585			}
1586			break;
1587#endif /* !FREEBSD */
1588		case PR_SYSENTRY:
1589#ifdef POLL_HACK
1590		        in_syscall = tcp;
1591#endif
1592		case PR_SYSEXIT:
1593			if (trace_syscall(tcp) < 0) {
1594				fprintf(stderr, "syscall trouble\n");
1595				exit(1);
1596			}
1597			break;
1598		case PR_SIGNALLED:
1599			if (!cflag && (qual_flags[what] & QUAL_SIGNAL)) {
1600				printleader(tcp);
1601				tprintf("--- %s (%s) ---",
1602					signame(what), strsignal(what));
1603				printtrailer(tcp);
1604#ifdef PR_INFO
1605				if (tcp->status.PR_INFO.si_signo == what) {
1606					printleader(tcp);
1607					tprintf("    siginfo=");
1608					printsiginfo(&tcp->status.PR_INFO, 1);
1609					printtrailer(tcp);
1610				}
1611#endif
1612			}
1613			break;
1614		case PR_FAULTED:
1615			if (!cflag && (qual_flags[what] & QUAL_FAULT)) {
1616				printleader(tcp);
1617				tprintf("=== FAULT %d ===", what);
1618				printtrailer(tcp);
1619			}
1620			break;
1621#ifdef FREEBSD
1622		case 0: /* handle case we polled for nothing */
1623		  	continue;
1624#endif
1625		default:
1626			fprintf(stderr, "odd stop %d\n", tcp->status.PR_WHY);
1627			exit(1);
1628			break;
1629		}
1630		arg = 0;
1631#ifndef FREEBSD
1632		if (IOCTL (tcp->pfd, PIOCRUN, &arg) < 0) {
1633#else
1634		if (IOCTL (tcp->pfd, PIOCRUN, 0) < 0) {
1635#endif
1636			perror("PIOCRUN");
1637			exit(1);
1638		}
1639	}
1640	return 0;
1641}
1642
1643#else /* !USE_PROCFS */
1644
1645static int
1646trace()
1647{
1648	int pid;
1649	int wait_errno;
1650	int status;
1651	struct tcb *tcp;
1652#ifdef LINUX
1653	struct rusage ru;
1654#ifdef __WALL
1655	static int wait4_options = __WALL;
1656#endif
1657#endif /* LINUX */
1658
1659	while (nprocs != 0) {
1660		if (interactive)
1661			sigprocmask(SIG_SETMASK, &empty_set, NULL);
1662#ifdef LINUX
1663#ifdef __WALL
1664		pid = wait4(-1, &status, wait4_options, cflag ? &ru : NULL);
1665		if ((wait4_options & __WALL) && errno == EINVAL) {
1666			/* this kernel does not support __WALL */
1667			wait4_options &= ~__WALL;
1668			errno = 0;
1669			pid = wait4(-1, &status, wait4_options,
1670					cflag ? &ru : NULL);
1671		}
1672		if (!(wait4_options & __WALL) && errno == ECHILD) {
1673			/* most likely a "cloned" process */
1674			pid = wait4(-1, &status, __WCLONE,
1675					cflag ? &ru : NULL);
1676			if (pid == -1) {
1677				fprintf(stderr, "strace: clone wait4 "
1678						"failed: %s\n", strerror(errno));
1679			}
1680		}
1681#else
1682		pid = wait4(-1, &status, 0, cflag ? &ru : NULL);
1683#endif /* __WALL */
1684#endif /* LINUX */
1685#ifdef SUNOS4
1686		pid = wait(&status);
1687#endif /* SUNOS4 */
1688		wait_errno = errno;
1689		if (interactive)
1690			sigprocmask(SIG_BLOCK, &blocked_set, NULL);
1691
1692		if (interrupted)
1693			return 0;
1694
1695		if (pid == -1) {
1696			switch (wait_errno) {
1697			case EINTR:
1698				continue;
1699			case ECHILD:
1700				/*
1701				 * We would like to verify this case
1702				 * but sometimes a race in Solbourne's
1703				 * version of SunOS sometimes reports
1704				 * ECHILD before sending us SIGCHILD.
1705				 */
1706#if 0
1707				if (nprocs == 0)
1708					return 0;
1709				fprintf(stderr, "strace: proc miscount\n");
1710				exit(1);
1711#endif
1712				return 0;
1713			default:
1714				errno = wait_errno;
1715				perror("strace: wait");
1716				return -1;
1717			}
1718		}
1719		if (debug)
1720			fprintf(stderr, " [wait(%#x) = %u]\n", status, pid);
1721
1722		/* Look up `pid' in our table. */
1723		if ((tcp = pid2tcb(pid)) == NULL) {
1724#if 0 /* XXX davidm */ /* WTA: disabled again */
1725			struct tcb *tcpchild;
1726
1727			if ((tcpchild = alloctcb(pid)) == NULL) {
1728				fprintf(stderr, " [tcb table full]\n");
1729				kill(pid, SIGKILL); /* XXX */
1730				return 0;
1731			}
1732			tcpchild->flags |= TCB_ATTACHED;
1733			newoutf(tcpchild);
1734			tcp->nchildren++;
1735			if (!qflag)
1736				fprintf(stderr, "Process %d attached\n", pid);
1737#else
1738			fprintf(stderr, "unknown pid: %u\n", pid);
1739			if (WIFSTOPPED(status))
1740				ptrace(PTRACE_CONT, pid, (char *) 1, 0);
1741			exit(1);
1742#endif
1743		}
1744		/* set current output file */
1745		outf = tcp->outf;
1746		if (cflag) {
1747#ifdef LINUX
1748			tv_sub(&tcp->dtime, &ru.ru_stime, &tcp->stime);
1749			tcp->stime = ru.ru_stime;
1750#endif /* !LINUX */
1751		}
1752
1753		if (tcp->flags & TCB_SUSPENDED) {
1754			/*
1755			 * Apparently, doing any ptrace() call on a stopped
1756			 * process, provokes the kernel to report the process
1757			 * status again on a subsequent wait(), even if the
1758			 * process has not been actually restarted.
1759			 * Since we have inspected the arguments of suspended
1760			 * processes we end up here testing for this case.
1761			 */
1762			continue;
1763		}
1764		if (WIFSIGNALED(status)) {
1765			if (!cflag
1766			    && (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)) {
1767				printleader(tcp);
1768				tprintf("+++ killed by %s +++",
1769					signame(WTERMSIG(status)));
1770				printtrailer(tcp);
1771			}
1772			droptcb(tcp);
1773			continue;
1774		}
1775		if (WIFEXITED(status)) {
1776			if (debug)
1777				fprintf(stderr, "pid %u exited\n", pid);
1778			if (tcp->flags & TCB_ATTACHED)
1779				fprintf(stderr,
1780					"PANIC: attached pid %u exited\n",
1781					pid);
1782			droptcb(tcp);
1783			continue;
1784		}
1785		if (!WIFSTOPPED(status)) {
1786			fprintf(stderr, "PANIC: pid %u not stopped\n", pid);
1787			droptcb(tcp);
1788			continue;
1789		}
1790		if (debug)
1791			fprintf(stderr, "pid %u stopped, [%s]\n",
1792				pid, signame(WSTOPSIG(status)));
1793
1794		if (tcp->flags & TCB_STARTUP) {
1795			/*
1796			 * This flag is there to keep us in sync.
1797			 * Next time this process stops it should
1798			 * really be entering a system call.
1799			 */
1800			tcp->flags &= ~TCB_STARTUP;
1801			if (tcp->flags & TCB_ATTACHED) {
1802				/*
1803				 * Interestingly, the process may stop
1804				 * with STOPSIG equal to some other signal
1805				 * than SIGSTOP if we happend to attach
1806				 * just before the process takes a signal.
1807				 */
1808				if (!WIFSTOPPED(status)) {
1809					fprintf(stderr,
1810						"pid %u not stopped\n", pid);
1811					detach(tcp, WSTOPSIG(status));
1812					continue;
1813				}
1814			}
1815			else {
1816#ifdef SUNOS4
1817				/* A child of us stopped at exec */
1818				if (WSTOPSIG(status) == SIGTRAP && followvfork)
1819					fixvfork(tcp);
1820#endif /* SUNOS4 */
1821			}
1822			if (tcp->flags & TCB_BPTSET) {
1823				if (clearbpt(tcp) < 0) /* Pretty fatal */ {
1824					droptcb(tcp);
1825					cleanup();
1826					return -1;
1827				}
1828			}
1829			goto tracing;
1830		}
1831
1832		if (WSTOPSIG(status) != SIGTRAP) {
1833			if (WSTOPSIG(status) == SIGSTOP &&
1834					(tcp->flags & TCB_SIGTRAPPED)) {
1835				/*
1836				 * Trapped attempt to block SIGTRAP
1837				 * Hope we are back in control now.
1838				 */
1839				tcp->flags &= ~(TCB_INSYSCALL | TCB_SIGTRAPPED);
1840				if (ptrace(PTRACE_SYSCALL,
1841						pid, (char *) 1, 0) < 0) {
1842					perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1843					cleanup();
1844					return -1;
1845				}
1846				continue;
1847			}
1848			if (!cflag
1849			    && (qual_flags[WSTOPSIG(status)] & QUAL_SIGNAL)) {
1850				unsigned long addr = 0, pc = 0;
1851#ifdef PT_GETSIGINFO
1852#				define PSR_RI	41
1853				struct siginfo si;
1854				unsigned long psr;
1855
1856				upeek(pid, PT_CR_IPSR, &psr);
1857				upeek(pid, PT_CR_IIP, &pc);
1858
1859				pc += (psr >> PSR_RI) & 0x3;
1860				ptrace(PT_GETSIGINFO, pid, 0, (long) &si);
1861				addr = (unsigned long) si.si_addr;
1862#endif
1863				printleader(tcp);
1864				tprintf("--- %s (%s) @ %lx (%lx) ---",
1865					signame(WSTOPSIG(status)),
1866					strsignal(WSTOPSIG(status)), pc, addr);
1867				printtrailer(tcp);
1868			}
1869			if ((tcp->flags & TCB_ATTACHED) &&
1870				!sigishandled(tcp, WSTOPSIG(status))) {
1871				detach(tcp, WSTOPSIG(status));
1872				continue;
1873			}
1874			if (ptrace(PTRACE_SYSCALL, pid, (char *) 1,
1875				   WSTOPSIG(status)) < 0) {
1876				perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1877				cleanup();
1878				return -1;
1879			}
1880			tcp->flags &= ~TCB_SUSPENDED;
1881			continue;
1882		}
1883		if (trace_syscall(tcp) < 0) {
1884			if (tcp->flags & TCB_ATTACHED)
1885				detach(tcp, 0);
1886			else {
1887				ptrace(PTRACE_KILL,
1888					tcp->pid, (char *) 1, SIGTERM);
1889				droptcb(tcp);
1890			}
1891			continue;
1892		}
1893		if (tcp->flags & TCB_EXITING) {
1894			if (tcp->flags & TCB_ATTACHED)
1895				detach(tcp, 0);
1896			else if (ptrace(PTRACE_CONT, pid, (char *) 1, 0) < 0) {
1897				perror("strace: ptrace(PTRACE_CONT, ...)");
1898				cleanup();
1899				return -1;
1900			}
1901			continue;
1902		}
1903		if (tcp->flags & TCB_SUSPENDED) {
1904			if (!qflag)
1905				fprintf(stderr, "Process %u suspended\n", pid);
1906			continue;
1907		}
1908	tracing:
1909		if (ptrace(PTRACE_SYSCALL, pid, (char *) 1, 0) < 0) {
1910			perror("trace: ptrace(PTRACE_SYSCALL, ...)");
1911			cleanup();
1912			return -1;
1913		}
1914	}
1915	return 0;
1916}
1917
1918#endif /* !USE_PROCFS */
1919
1920static int curcol;
1921
1922#ifdef __STDC__
1923#include <stdarg.h>
1924#define VA_START(a, b) va_start(a, b)
1925#else
1926#include <varargs.h>
1927#define VA_START(a, b) va_start(a)
1928#endif
1929
1930void
1931#ifdef __STDC__
1932tprintf(const char *fmt, ...)
1933#else
1934tprintf(fmt, va_alist)
1935char *fmt;
1936va_dcl
1937#endif
1938{
1939	va_list args;
1940
1941	VA_START(args, fmt);
1942	if (outf)
1943		curcol += vfprintf(outf, fmt, args);
1944	va_end(args);
1945	return;
1946}
1947
1948void
1949printleader(tcp)
1950struct tcb *tcp;
1951{
1952	if (tcp_last && (!outfname || followfork < 2 || tcp_last == tcp)) {
1953		tcp_last->flags |= TCB_REPRINT;
1954		tprintf(" <unfinished ...>\n");
1955	}
1956	curcol = 0;
1957	if ((followfork == 1 || pflag_seen > 1) && outfname)
1958		tprintf("%-5d ", tcp->pid);
1959	else if (nprocs > 1 && !outfname)
1960		tprintf("[pid %5u] ", tcp->pid);
1961	if (tflag) {
1962		char str[sizeof("HH:MM:SS")];
1963		struct timeval tv, dtv;
1964		static struct timeval otv;
1965
1966		gettimeofday(&tv, NULL);
1967		if (rflag) {
1968			if (otv.tv_sec == 0)
1969				otv = tv;
1970			tv_sub(&dtv, &tv, &otv);
1971			tprintf("%6ld.%06ld ",
1972				(long) dtv.tv_sec, (long) dtv.tv_usec);
1973			otv = tv;
1974		}
1975		else if (tflag > 2) {
1976			tprintf("%ld.%06ld ",
1977				(long) tv.tv_sec, (long) tv.tv_usec);
1978		}
1979		else {
1980			time_t local = tv.tv_sec;
1981			strftime(str, sizeof(str), "%T", localtime(&local));
1982			if (tflag > 1)
1983				tprintf("%s.%06ld ", str, (long) tv.tv_usec);
1984			else
1985				tprintf("%s ", str);
1986		}
1987	}
1988	if (iflag)
1989		printcall(tcp);
1990}
1991
1992void
1993tabto(col)
1994int col;
1995{
1996	if (curcol < col)
1997		tprintf("%*s", col - curcol, "");
1998}
1999
2000void
2001printtrailer(tcp)
2002struct tcb *tcp;
2003{
2004	tprintf("\n");
2005	tcp_last = NULL;
2006}
2007
2008#ifdef HAVE_MP_PROCFS
2009
2010int mp_ioctl (int fd, int cmd, void *arg, int size) {
2011
2012	struct iovec iov[2];
2013	int n = 1;
2014
2015	iov[0].iov_base = &cmd;
2016	iov[0].iov_len = sizeof cmd;
2017	if (arg) {
2018		++n;
2019		iov[1].iov_base = arg;
2020		iov[1].iov_len = size;
2021	}
2022
2023	return writev (fd, iov, n);
2024}
2025
2026#endif
2027