main.c revision 132306 
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 132306 2004-07-17 19:19:36Z alfred $");
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 __inline void
70usage(void)
71{
72  fprintf(stderr, "%s\n%s\n",
73	"usage: truss [-faedDS] [-o file] -p pid",
74	"       truss [-faedDS] [-o file] 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 __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.  The procfs pseudo-file "etype" has
111 * the execution module type -- see /proc/curproc/etype for an example.
112 */
113
114static struct ex_types *
115set_etype(struct trussinfo *trussinfo) {
116  struct ex_types *funcs;
117  char etype[24];
118  char progt[32];
119  int fd;
120
121  sprintf(etype, "/proc/%d/etype", trussinfo->pid);
122  if ((fd = open(etype, O_RDONLY)) == -1) {
123    strcpy(progt, "FreeBSD a.out");
124  } else {
125    int len = read(fd, progt, sizeof(progt));
126    progt[len-1] = '\0';
127    close(fd);
128  }
129
130  for (funcs = ex_types; funcs->type; funcs++)
131    if (!strcmp(funcs->type, progt))
132      break;
133
134  if (funcs->type == NULL) {
135    funcs = &ex_types[0];
136    warn("execution type %s is not supported -- using %s",
137      progt, funcs->type);
138  }
139  return funcs;
140}
141
142char *
143strsig(int sig)
144{
145	char *ret;
146
147	ret = NULL;
148	if (sig > 0 && sig < NSIG) {
149		int i;
150		asprintf(&ret, "sig%s", sys_signame[sig]);
151		if (ret == NULL)
152			return (NULL);
153		for (i = 0; ret[i] != '\0'; ++i)
154			ret[i] = toupper(ret[i]);
155	}
156	return (ret);
157}
158
159int
160main(int ac, char **av) {
161  int c;
162  int i;
163  char **command;
164  struct procfs_status pfs;
165  struct ex_types *funcs;
166  int in_exec = 0;
167  char *fname = NULL;
168  int sigexit = 0;
169  struct trussinfo *trussinfo;
170  char *signame;
171
172  /* Initialize the trussinfo struct */
173  trussinfo = (struct trussinfo *)malloc(sizeof(struct trussinfo));
174  if (trussinfo == NULL)
175    errx(1, "malloc() failed");
176  bzero(trussinfo, sizeof(struct trussinfo));
177  trussinfo->outfile = stderr;
178
179  while ((c = getopt(ac, av, "p:o:faedDS")) != -1) {
180    switch (c) {
181    case 'p':	/* specified pid */
182      trussinfo->pid = atoi(optarg);
183      break;
184    case 'f': /* Follow fork()'s */
185      trussinfo->flags |= FOLLOWFORKS;
186      break;
187    case 'a': /* Print execve() argument strings. */
188      trussinfo->flags |= EXECVEARGS;
189      break;
190    case 'e': /* Print execve() environment strings. */
191      trussinfo->flags |= EXECVEENVS;
192      break;
193    case 'd': /* Absolute timestamps */
194      trussinfo->flags |= ABSOLUTETIMESTAMPS;
195      break;
196    case 'D': /* Relative timestamps */
197      trussinfo->flags |= RELATIVETIMESTAMPS;
198      break;
199    case 'o':	/* Specified output file */
200      fname = optarg;
201      break;
202    case 'S':	/* Don't trace signals */
203      trussinfo->flags |= NOSIGS;
204      break;
205    default:
206      usage();
207    }
208  }
209
210  ac -= optind; av += optind;
211  if ((trussinfo->pid == 0 && ac == 0) || (trussinfo->pid != 0 && ac != 0))
212    usage();
213
214  if (fname != NULL) { /* Use output file */
215    if ((trussinfo->outfile = fopen(fname, "w")) == NULL)
216      errx(1, "cannot open %s", fname);
217  }
218
219  /*
220   * If truss starts the process itself, it will ignore some signals --
221   * they should be passed off to the process, which may or may not
222   * exit.  If, however, we are examining an already-running process,
223   * then we restore the event mask on these same signals.
224   */
225
226  if (trussinfo->pid == 0) {	/* Start a command ourselves */
227    command = av;
228    trussinfo->pid = setup_and_wait(command);
229    signal(SIGINT, SIG_IGN);
230    signal(SIGTERM, SIG_IGN);
231    signal(SIGQUIT, SIG_IGN);
232  } else {
233    signal(SIGINT, restore_proc);
234    signal(SIGTERM, restore_proc);
235    signal(SIGQUIT, restore_proc);
236  }
237
238
239  /*
240   * At this point, if we started the process, it is stopped waiting to
241   * be woken up, either in exit() or in execve().
242   */
243
244START_TRACE:
245  Procfd = start_tracing(
246		trussinfo->pid, S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT |
247		((trussinfo->flags & NOSIGS) ? 0 : S_SIG),
248		((trussinfo->flags & FOLLOWFORKS) ? PF_FORK : 0));
249  if (Procfd == -1)
250    return 0;
251
252  pfs.why = 0;
253
254  funcs = set_etype(trussinfo);
255  /*
256   * At this point, it's a simple loop, waiting for the process to
257   * stop, finding out why, printing out why, and then continuing it.
258   * All of the grunt work is done in the support routines.
259   */
260
261  clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);
262
263  do {
264    int val = 0;
265
266    if (ioctl(Procfd, PIOCWAIT, &pfs) == -1)
267      warn("PIOCWAIT top of loop");
268    else {
269      switch(i = pfs.why) {
270      case S_SCE:
271	funcs->enter_syscall(trussinfo, pfs.val);
272	clock_gettime(CLOCK_REALTIME, &trussinfo->before);
273	break;
274      case S_SCX:
275	clock_gettime(CLOCK_REALTIME, &trussinfo->after);
276	/*
277	 * This is so we don't get two messages for an exec -- one
278	 * for the S_EXEC, and one for the syscall exit.  It also,
279	 * conveniently, ensures that the first message printed out
280	 * isn't the return-from-syscall used to create the process.
281	 */
282
283	if (in_exec) {
284	  in_exec = 0;
285	  break;
286	}
287
288	if (trussinfo->in_fork && (trussinfo->flags & FOLLOWFORKS)) {
289	  int childpid;
290
291	  trussinfo->in_fork = 0;
292	  childpid = funcs->exit_syscall(trussinfo, pfs.val);
293
294	  /*
295	   * Fork a new copy of ourself to trace the child of the
296	   * original traced process.
297	   */
298	  if (fork() == 0) {
299	    trussinfo->pid = childpid;
300	    goto START_TRACE;
301	  }
302	  break;
303	}
304	funcs->exit_syscall(trussinfo, pfs.val);
305	break;
306      case S_SIG:
307	signame = strsig(pfs.val);
308	fprintf(trussinfo->outfile, "SIGNAL %lu (%s)\n", pfs.val,
309	    signame == NULL ? "?" : signame);
310	free(signame);
311	sigexit = pfs.val;
312	break;
313      case S_EXIT:
314	fprintf (trussinfo->outfile, "process exit, rval = %lu\n", pfs.val);
315	break;
316      case S_EXEC:
317	funcs = set_etype(trussinfo);
318	in_exec = 1;
319	break;
320      default:
321	fprintf (trussinfo->outfile, "Process stopped because of:  %d\n", i);
322	break;
323      }
324    }
325    if (ioctl(Procfd, PIOCCONT, val) == -1) {
326      if (kill(trussinfo->pid, 0) == -1 && errno == ESRCH)
327	break;
328      else
329	warn("PIOCCONT");
330    }
331  } while (pfs.why != S_EXIT);
332  fflush(trussinfo->outfile);
333  if (sigexit) {
334    struct rlimit rlp;
335
336    rlp.rlim_cur = 0;
337    rlp.rlim_max = 0;
338    setrlimit(RLIMIT_CORE, &rlp);
339    (void) signal(sigexit, SIG_DFL);
340    (void) kill(getpid(), sigexit);
341  }
342  return 0;
343}
344