main.c revision 179051 
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 179051 2008-05-16 15:34:06Z jhb $");
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/types.h>
43#include <sys/time.h>
44#include <sys/resource.h>
45#include <sys/sysctl.h>
46
47#include <ctype.h>
48#include <err.h>
49#include <errno.h>
50#include <fcntl.h>
51#include <signal.h>
52#include <stdio.h>
53#include <stdlib.h>
54#include <string.h>
55#include <time.h>
56#include <unistd.h>
57
58#include "truss.h"
59#include "extern.h"
60
61#define MAXARGS 6
62
63static void
64usage(void)
65{
66	fprintf(stderr, "%s\n%s\n",
67	    "usage: truss [-faedDS] [-o file] [-s strsize] -p pid",
68	    "       truss [-faedDS] [-o file] [-s strsize] command [args]");
69	exit(1);
70}
71
72/*
73 * WARNING! "FreeBSD a.out" must be first, or set_etype will not
74 * work correctly.
75 */
76struct ex_types {
77	const char *type;
78	void (*enter_syscall)(struct trussinfo *, int);
79	long (*exit_syscall)(struct trussinfo *, int);
80} ex_types[] = {
81#ifdef __alpha__
82	{ "FreeBSD ELF", alpha_syscall_entry, alpha_syscall_exit },
83#endif
84#ifdef __amd64__
85	{ "FreeBSD ELF64", amd64_syscall_entry, amd64_syscall_exit },
86	{ "FreeBSD ELF32", amd64_fbsd32_syscall_entry, amd64_fbsd32_syscall_exit },
87	{ "Linux ELF32", amd64_linux32_syscall_entry, amd64_linux32_syscall_exit },
88#endif
89#ifdef __i386__
90	{ "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit },
91	{ "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit },
92	{ "FreeBSD ELF32", i386_syscall_entry, i386_syscall_exit },
93	{ "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit },
94#endif
95#ifdef __ia64__
96	{ "FreeBSD ELF64", ia64_syscall_entry, ia64_syscall_exit },
97#endif
98#ifdef __powerpc__
99	{ "FreeBSD ELF", powerpc_syscall_entry, powerpc_syscall_exit },
100	{ "FreeBSD ELF32", powerpc_syscall_entry, powerpc_syscall_exit },
101#endif
102#ifdef __sparc64__
103	{ "FreeBSD ELF64", sparc64_syscall_entry, sparc64_syscall_exit },
104#endif
105	{ 0, 0, 0 },
106};
107
108/*
109 * Set the execution type.  This is called after every exec, and when
110 * a process is first monitored.
111 */
112
113static struct ex_types *
114set_etype(struct trussinfo *trussinfo)
115{
116	struct ex_types *funcs;
117	char progt[32];
118
119	size_t len = sizeof(progt);
120	int mib[4];
121	int error;
122
123	mib[0] = CTL_KERN;
124	mib[1] = KERN_PROC;
125	mib[2] = KERN_PROC_SV_NAME;
126	mib[3] = trussinfo->pid;
127	error = sysctl(mib, 4, progt, &len, NULL, 0);
128	if (error != 0)
129		err(2, "can not get etype");
130
131	for (funcs = ex_types; funcs->type; funcs++)
132		if (!strcmp(funcs->type, progt))
133			break;
134
135	if (funcs->type == NULL) {
136		funcs = &ex_types[0];
137		warn("execution type %s is not supported -- using %s",
138		    progt, funcs->type);
139	}
140	return (funcs);
141}
142
143char *
144strsig(int sig)
145{
146	char *ret;
147
148	ret = NULL;
149	if (sig > 0 && sig < NSIG) {
150		int i;
151		asprintf(&ret, "sig%s", sys_signame[sig]);
152		if (ret == NULL)
153			return (NULL);
154		for (i = 0; ret[i] != '\0'; ++i)
155			ret[i] = toupper(ret[i]);
156	}
157	return (ret);
158}
159
160int
161main(int ac, char **av)
162{
163	int c;
164	int i;
165	char **command;
166	struct ex_types *funcs;
167	int initial_open;
168	char *fname;
169	struct trussinfo *trussinfo;
170	char *signame;
171
172	fname = NULL;
173	initial_open = 1;
174
175	/* Initialize the trussinfo struct */
176	trussinfo = (struct trussinfo *)malloc(sizeof(struct trussinfo));
177	if (trussinfo == NULL)
178		errx(1, "malloc() failed");
179	bzero(trussinfo, sizeof(struct trussinfo));
180
181	trussinfo->outfile = stderr;
182	trussinfo->strsize = 32;
183	trussinfo->pr_why = S_NONE;
184	trussinfo->curthread = NULL;
185	SLIST_INIT(&trussinfo->threadlist);
186	while ((c = getopt(ac, av, "p:o:faedDs:S")) != -1) {
187		switch (c) {
188		case 'p':	/* specified pid */
189			trussinfo->pid = atoi(optarg);
190			/* make sure i don't trace me */
191			if(trussinfo->pid == getpid()) {
192				fprintf(stderr, "attempt to grab self.\n");
193				exit(2);
194			}
195			break;
196		case 'f': /* Follow fork()'s */
197			trussinfo->flags |= FOLLOWFORKS;
198			break;
199		case 'a': /* Print execve() argument strings. */
200			trussinfo->flags |= EXECVEARGS;
201			break;
202		case 'e': /* Print execve() environment strings. */
203			trussinfo->flags |= EXECVEENVS;
204			break;
205		case 'd': /* Absolute timestamps */
206			trussinfo->flags |= ABSOLUTETIMESTAMPS;
207			break;
208		case 'D': /* Relative timestamps */
209			trussinfo->flags |= RELATIVETIMESTAMPS;
210			break;
211		case 'o':	/* Specified output file */
212			fname = optarg;
213			break;
214		case 's':	/* Specified string size */
215			trussinfo->strsize = atoi(optarg);
216			break;
217		case 'S':	/* Don't trace signals */
218			trussinfo->flags |= NOSIGS;
219			break;
220		default:
221			usage();
222		}
223	}
224
225	ac -= optind; av += optind;
226	if ((trussinfo->pid == 0 && ac == 0) ||
227	    (trussinfo->pid != 0 && ac != 0))
228		usage();
229
230	if (fname != NULL) { /* Use output file */
231		if ((trussinfo->outfile = fopen(fname, "w")) == NULL)
232			errx(1, "cannot open %s", fname);
233	}
234
235	/*
236	 * If truss starts the process itself, it will ignore some signals --
237	 * they should be passed off to the process, which may or may not
238	 * exit.  If, however, we are examining an already-running process,
239	 * then we restore the event mask on these same signals.
240	 */
241
242	if (trussinfo->pid == 0) {	/* Start a command ourselves */
243		command = av;
244		trussinfo->pid = setup_and_wait(command);
245		signal(SIGINT, SIG_IGN);
246		signal(SIGTERM, SIG_IGN);
247		signal(SIGQUIT, SIG_IGN);
248	} else {
249		start_tracing(trussinfo->pid);
250		signal(SIGINT, restore_proc);
251		signal(SIGTERM, restore_proc);
252		signal(SIGQUIT, restore_proc);
253	}
254
255
256	/*
257	 * At this point, if we started the process, it is stopped waiting to
258	 * be woken up, either in exit() or in execve().
259	 */
260
261START_TRACE:
262	funcs = set_etype(trussinfo);
263
264	initial_open = 0;
265	/*
266	 * At this point, it's a simple loop, waiting for the process to
267	 * stop, finding out why, printing out why, and then continuing it.
268	 * All of the grunt work is done in the support routines.
269	 */
270
271	clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);
272
273	do {
274		struct timespec timediff;
275		waitevent(trussinfo);
276
277		switch(i = trussinfo->pr_why) {
278		case S_SCE:
279			funcs->enter_syscall(trussinfo, MAXARGS);
280			clock_gettime(CLOCK_REALTIME,
281			    &trussinfo->before);
282			break;
283		case S_SCX:
284			clock_gettime(CLOCK_REALTIME,
285			    &trussinfo->after);
286
287			if (trussinfo->curthread->in_fork &&
288			    (trussinfo->flags & FOLLOWFORKS)) {
289				int childpid;
290
291				trussinfo->curthread->in_fork = 0;
292				childpid =
293				    funcs->exit_syscall(trussinfo,
294					trussinfo->pr_data);
295
296				/*
297				 * Fork a new copy of ourself to trace
298				 * the child of the original traced
299				 * process.
300				 */
301				if (fork() == 0) {
302					trussinfo->pid = childpid;
303					start_tracing(trussinfo->pid);
304					goto START_TRACE;
305				}
306				break;
307			}
308			funcs->exit_syscall(trussinfo, MAXARGS);
309			break;
310		case S_SIG:
311			if (trussinfo->flags & NOSIGS)
312				break;
313			if (trussinfo->flags & FOLLOWFORKS)
314				fprintf(trussinfo->outfile, "%5d: ",
315				    trussinfo->pid);
316			if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
317				timespecsubt(&trussinfo->after,
318				    &trussinfo->start_time, &timediff);
319				fprintf(trussinfo->outfile, "%ld.%09ld ",
320				    (long)timediff.tv_sec,
321				    timediff.tv_nsec);
322			}
323			if (trussinfo->flags & RELATIVETIMESTAMPS) {
324				timespecsubt(&trussinfo->after,
325				    &trussinfo->before, &timediff);
326				fprintf(trussinfo->outfile, "%ld.%09ld ",
327				    (long)timediff.tv_sec,
328				    timediff.tv_nsec);
329			}
330			signame = strsig(trussinfo->pr_data);
331			fprintf(trussinfo->outfile,
332			    "SIGNAL %u (%s)\n", trussinfo->pr_data,
333			    signame == NULL ? "?" : signame);
334			free(signame);
335			break;
336		case S_EXIT:
337			if (trussinfo->flags & FOLLOWFORKS)
338				fprintf(trussinfo->outfile, "%5d: ",
339				    trussinfo->pid);
340			if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
341				timespecsubt(&trussinfo->after,
342				    &trussinfo->start_time, &timediff);
343				fprintf(trussinfo->outfile, "%ld.%09ld ",
344				    (long)timediff.tv_sec,
345				    timediff.tv_nsec);
346			}
347			if (trussinfo->flags & RELATIVETIMESTAMPS) {
348			  timespecsubt(&trussinfo->after,
349			      &trussinfo->before, &timediff);
350			  fprintf(trussinfo->outfile, "%ld.%09ld ",
351			    (long)timediff.tv_sec, timediff.tv_nsec);
352			}
353			fprintf(trussinfo->outfile,
354			    "process exit, rval = %u\n", trussinfo->pr_data);
355			break;
356		default:
357			break;
358		}
359	} while (trussinfo->pr_why != S_EXIT);
360	fflush(trussinfo->outfile);
361
362	return (0);
363}
364