main.c revision 154047 
1/*
2 * Copryight 1997 Sean Eric Fagan
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 * 3. All advertising materials mentioning features or use of this software
13 *    must display the following acknowledgement:
14 *	This product includes software developed by Sean Eric Fagan
15 * 4. Neither the name of the author may be used to endorse or promote
16 *    products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/usr.bin/truss/main.c 154047 2006-01-05 05:57:47Z grehan $");
34
35/*
36 * The main module for truss.  Suprisingly simple, but, then, the other
37 * files handle the bulk of the work.  And, of course, the kernel has to
38 * do a lot of the work :).
39 */
40
41#include <sys/param.h>
42#include <sys/ioctl.h>
43#include <sys/pioctl.h>
44#include <sys/types.h>
45#include <sys/time.h>
46#include <sys/resource.h>
47
48#include <ctype.h>
49#include <err.h>
50#include <errno.h>
51#include <fcntl.h>
52#include <signal.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <time.h>
57#include <unistd.h>
58
59#include "truss.h"
60#include "extern.h"
61
62/*
63 * It's difficult to parameterize this because it must be
64 * accessible in a signal handler.
65 */
66
67int Procfd;
68
69static void
70usage(void)
71{
72	fprintf(stderr, "%s\n%s\n",
73	    "usage: truss [-faedDS] [-o file] [-s strsize] -p pid",
74	    "       truss [-faedDS] [-o file] [-s strsize] command [args]");
75	exit(1);
76}
77
78/*
79 * WARNING! "FreeBSD a.out" must be first, or set_etype will not
80 * work correctly.
81 */
82struct ex_types {
83	const char *type;
84	void (*enter_syscall)(struct trussinfo *, int);
85	long (*exit_syscall)(struct trussinfo *, int);
86} ex_types[] = {
87#ifdef __alpha__
88	{ "FreeBSD ELF", alpha_syscall_entry, alpha_syscall_exit },
89#endif
90#ifdef __amd64__
91	{ "FreeBSD ELF64", amd64_syscall_entry, amd64_syscall_exit },
92#endif
93#ifdef __i386__
94	{ "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit },
95	{ "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit },
96	{ "FreeBSD ELF32", i386_syscall_entry, i386_syscall_exit },
97	{ "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit },
98#endif
99#ifdef __ia64__
100	{ "FreeBSD ELF64", ia64_syscall_entry, ia64_syscall_exit },
101#endif
102#ifdef __powerpc__
103	{ "FreeBSD ELF", powerpc_syscall_entry, powerpc_syscall_exit },
104	{ "FreeBSD ELF32", powerpc_syscall_entry, powerpc_syscall_exit },
105#endif
106#ifdef __sparc64__
107	{ "FreeBSD ELF64", sparc64_syscall_entry, sparc64_syscall_exit },
108#endif
109	{ 0, 0, 0 },
110};
111
112/*
113 * Set the execution type.  This is called after every exec, and when
114 * a process is first monitored.  The procfs pseudo-file "etype" has
115 * the execution module type -- see /proc/curproc/etype for an example.
116 */
117
118static struct ex_types *
119set_etype(struct trussinfo *trussinfo)
120{
121	struct ex_types *funcs;
122	char etype[24];
123	char progt[32];
124	int fd;
125
126	sprintf(etype, "/proc/%d/etype", trussinfo->pid);
127	if ((fd = open(etype, O_RDONLY)) == -1) {
128		strcpy(progt, "FreeBSD a.out");
129	} else {
130		int len = read(fd, progt, sizeof(progt));
131		progt[len-1] = '\0';
132		close(fd);
133	}
134
135	for (funcs = ex_types; funcs->type; funcs++)
136		if (!strcmp(funcs->type, progt))
137			break;
138
139	if (funcs->type == NULL) {
140		funcs = &ex_types[0];
141		warn("execution type %s is not supported -- using %s",
142		    progt, funcs->type);
143	}
144	return (funcs);
145}
146
147char *
148strsig(int sig)
149{
150	char *ret;
151
152	ret = NULL;
153	if (sig > 0 && sig < NSIG) {
154		int i;
155		asprintf(&ret, "sig%s", sys_signame[sig]);
156		if (ret == NULL)
157			return (NULL);
158		for (i = 0; ret[i] != '\0'; ++i)
159			ret[i] = toupper(ret[i]);
160	}
161	return (ret);
162}
163
164int
165main(int ac, char **av)
166{
167	int c;
168	int i;
169	char **command;
170	struct procfs_status pfs;
171	struct ex_types *funcs;
172	int in_exec, sigexit, initial_open;
173	char *fname;
174	struct trussinfo *trussinfo;
175	char *signame;
176
177	in_exec = 0;
178	sigexit = 0;
179	fname = NULL;
180	initial_open = 1;
181
182	/* Initialize the trussinfo struct */
183	trussinfo = (struct trussinfo *)malloc(sizeof(struct trussinfo));
184	if (trussinfo == NULL)
185		errx(1, "malloc() failed");
186	bzero(trussinfo, sizeof(struct trussinfo));
187	trussinfo->outfile = stderr;
188	trussinfo->strsize = 32;
189
190	while ((c = getopt(ac, av, "p:o:faedDs:S")) != -1) {
191		switch (c) {
192		case 'p':	/* specified pid */
193			trussinfo->pid = atoi(optarg);
194			break;
195		case 'f': /* Follow fork()'s */
196			trussinfo->flags |= FOLLOWFORKS;
197			break;
198		case 'a': /* Print execve() argument strings. */
199			trussinfo->flags |= EXECVEARGS;
200			break;
201		case 'e': /* Print execve() environment strings. */
202			trussinfo->flags |= EXECVEENVS;
203			break;
204		case 'd': /* Absolute timestamps */
205			trussinfo->flags |= ABSOLUTETIMESTAMPS;
206			break;
207		case 'D': /* Relative timestamps */
208			trussinfo->flags |= RELATIVETIMESTAMPS;
209			break;
210		case 'o':	/* Specified output file */
211			fname = optarg;
212			break;
213		case 's':	/* Specified string size */
214			trussinfo->strsize = atoi(optarg);
215			break;
216		case 'S':	/* Don't trace signals */
217			trussinfo->flags |= NOSIGS;
218			break;
219		default:
220			usage();
221		}
222	}
223
224	ac -= optind; av += optind;
225	if ((trussinfo->pid == 0 && ac == 0) ||
226	    (trussinfo->pid != 0 && ac != 0))
227		usage();
228
229	if (fname != NULL) { /* Use output file */
230		if ((trussinfo->outfile = fopen(fname, "w")) == NULL)
231			errx(1, "cannot open %s", fname);
232	}
233
234	/*
235	 * If truss starts the process itself, it will ignore some signals --
236	 * they should be passed off to the process, which may or may not
237	 * exit.  If, however, we are examining an already-running process,
238	 * then we restore the event mask on these same signals.
239	 */
240
241	if (trussinfo->pid == 0) {	/* Start a command ourselves */
242		command = av;
243		trussinfo->pid = setup_and_wait(command);
244		signal(SIGINT, SIG_IGN);
245		signal(SIGTERM, SIG_IGN);
246		signal(SIGQUIT, SIG_IGN);
247	} else {
248		signal(SIGINT, restore_proc);
249		signal(SIGTERM, restore_proc);
250		signal(SIGQUIT, restore_proc);
251	}
252
253
254	/*
255	 * At this point, if we started the process, it is stopped waiting to
256	 * be woken up, either in exit() or in execve().
257	 */
258
259START_TRACE:
260	Procfd = start_tracing(
261	    trussinfo->pid, initial_open,
262	    S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT |
263	    ((trussinfo->flags & NOSIGS) ? 0 : S_SIG),
264	    ((trussinfo->flags & FOLLOWFORKS) ? PF_FORK : 0));
265	initial_open = 0;
266	if (Procfd == -1)
267		return (0);
268
269	pfs.why = 0;
270
271	funcs = set_etype(trussinfo);
272	/*
273	 * At this point, it's a simple loop, waiting for the process to
274	 * stop, finding out why, printing out why, and then continuing it.
275	 * All of the grunt work is done in the support routines.
276	 */
277
278	clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);
279
280	do {
281		int val = 0;
282
283		if (ioctl(Procfd, PIOCWAIT, &pfs) == -1)
284			warn("PIOCWAIT top of loop");
285		else {
286			switch(i = pfs.why) {
287			case S_SCE:
288				funcs->enter_syscall(trussinfo, pfs.val);
289				clock_gettime(CLOCK_REALTIME,
290				    &trussinfo->before);
291				break;
292			case S_SCX:
293				clock_gettime(CLOCK_REALTIME,
294				    &trussinfo->after);
295				/*
296				 * This is so we don't get two messages for
297				 * an exec -- one for the S_EXEC, and one for
298				 * the syscall exit.  It also, conveniently,
299				 * ensures that the first message printed out
300				 * isn't the return-from-syscall used to
301				 * create the process.
302				 */
303				if (in_exec) {
304					in_exec = 0;
305					break;
306				}
307
308				if (trussinfo->in_fork &&
309				    (trussinfo->flags & FOLLOWFORKS)) {
310					int childpid;
311
312					trussinfo->in_fork = 0;
313					childpid =
314					    funcs->exit_syscall(trussinfo,
315						pfs.val);
316
317					/*
318					 * Fork a new copy of ourself to trace
319					 * the child of the original traced
320					 * process.
321					 */
322					if (fork() == 0) {
323						trussinfo->pid = childpid;
324						goto START_TRACE;
325					}
326					break;
327				}
328				funcs->exit_syscall(trussinfo, pfs.val);
329				break;
330			case S_SIG:
331				signame = strsig(pfs.val);
332				fprintf(trussinfo->outfile,
333				    "SIGNAL %lu (%s)\n", pfs.val,
334				    signame == NULL ? "?" : signame);
335				free(signame);
336				sigexit = pfs.val;
337				break;
338			case S_EXIT:
339				fprintf(trussinfo->outfile,
340				    "process exit, rval = %lu\n", pfs.val);
341				break;
342			case S_EXEC:
343				funcs = set_etype(trussinfo);
344				in_exec = 1;
345				break;
346			default:
347				fprintf(trussinfo->outfile,
348				    "Process stopped because of:  %d\n", i);
349				break;
350			}
351		}
352		if (ioctl(Procfd, PIOCCONT, val) == -1) {
353			if (kill(trussinfo->pid, 0) == -1 && errno == ESRCH)
354				break;
355			else
356				warn("PIOCCONT");
357		}
358	} while (pfs.why != S_EXIT);
359	fflush(trussinfo->outfile);
360	if (sigexit) {
361		struct rlimit rlp;
362
363		rlp.rlim_cur = 0;
364		rlp.rlim_max = 0;
365		setrlimit(RLIMIT_CORE, &rlp);
366		(void) signal(sigexit, SIG_DFL);
367		(void) kill(getpid(), sigexit);
368	}
369	return (0);
370}
371