3 * Run a command with a timeout.
5 * (c) 2011 Mark Wooding
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the Toys utilties collection.
12 * Toys is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * Toys is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with Toys; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Basic strategy ----------------------------------------------------*
29 * There's an obvious and simple way to make a process stop after a certain
30 * amount of time: set an alarm. Alarms are inherited, so this will take
31 * down the whole subprocess tree. Unfortunately, processes use alarms for
32 * all sorts of things. And this relies on the process not fiddling with its
35 * The other possibility is to have a separate process which kills our target
36 * program when the time's up. In order to do this effectively, we need to
37 * trap the whole thing in a process group. Then we need to wait until the
38 * time is up or the process finished. We'll assume that the top-level
39 * process finishing is sufficient indication that we don't need to hang on
42 * This isn't perfect. It won't catch stragglers if the target process
43 * creates its own sub-process groups -- so, in particular, nested timeouts
44 * won't behave in an obvious way. And, possibly most annoyingly, it
45 * interferes with the way terminal I/O works. I'm sorry: you can't have
49 /*----- Header files ------------------------------------------------------*/
59 #include <sys/types.h>
63 #include <sys/select.h>
66 #include <mLib/fdflags.h>
67 #include <mLib/macros.h>
68 #include <mLib/mdwopt.h>
69 #include <mLib/quis.h>
70 #include <mLib/report.h>
75 /*----- Static variables --------------------------------------------------*/
86 /*----- Argument conversion functions -------------------------------------*/
88 /* --- @namesig@ --- *
90 * Arguments: @const char *p@ = pointer to string
92 * Returns: Signal number, or @-1@ for no match.
94 * Use: Converts a signal name into its number.
102 int cmp_namesig(const void *k, const void *v)
103 { const struct namesig *ns = v; return (strcmp(k, ns->name)); }
105 static int namesig(const char *p)
107 const static struct namesig tab[] = {
109 ;;; The signal name table is very boring to type. To make life less
110 ;;; awful, put the signal names in this list and evaluate the code to
111 ;;; get Emacs to regenerate it. We use @bsearch@ on it, so it's
112 ;;; important that it be sorted: Emacs does this for us.
114 (let ((signals '(HUP INT QUIT ILL ABRT FPE KILL SEGV PIPE ALRM TERM
115 USR1 USR2 CHLD CONT STOP TSTP TTIN TTOU BUS POLL
116 PROF SYS TRAP URG VTALRM XCPU XFSZ IOT EMT STKFLT
117 IO CLD PWR INFO LOST WINCH)))
119 (goto-char (point-min))
120 (search-forward (concat "***" "BEGIN siglist" "***"))
121 (beginning-of-line 2)
122 (delete-region (point)
124 (search-forward "***END***")
127 (dolist (sig (sort (copy-list signals) #'string<))
128 (insert (format "#ifdef SIG%s\n { \"%s\", SIG%s },\n#endif\n"
132 /***BEGIN siglist***/
200 { "STKFLT", SIGSTKFLT },
233 { "VTALRM", SIGVTALRM },
236 { "WINCH", SIGWINCH },
247 const struct namesig *ns = bsearch(p, tab, N(tab), sizeof(tab[0]),
249 if (ns) return (ns->sig);
250 else if (isdigit((unsigned char)*p)) return (atoi(p));
254 /* --- @strtotime@ --- *
256 * Arguments: @const char *p@ = pointer to string
257 * @struct timeval *tv@ = where to put the result
261 * Use: Converts a string representation of a duration into an
262 * internal version. Understands various time units.
265 static void strtotime(const char *p, struct timeval *tv)
267 char *q = (/*unconst*/ char *)p;
270 while (isspace((unsigned char)*q)) q++;
272 while (isspace((unsigned char)*q)) q++;
274 case 'd': case 'D': t *= 24;
275 case 'h': case 'H': t *= 60;
276 case 'm': case 'M': t *= 60;
279 while (isspace((unsigned char)*q)) q++;
281 if (*q) die(253, "bad time value `%s'", p);
284 tv->tv_usec = f * 1000000;
287 /*----- Help functions ----------------------------------------------------*/
289 static void usage(FILE *fp)
290 { pquis(fp, "Usage: $ [-s SIG] SECONDS COMMAND [ARGUMENTS ...]\n"); }
292 static void version(FILE *fp)
293 { pquis(fp, "$ (version " VERSION ")\n"); }
295 static void help(FILE *fp)
297 version(fp); fputc('\n', stdout);
300 Run COMMAND, giving it the ARGUMENTS. If it fails to complete within the\n\
301 specified number of SECONDS, kill it. Otherwise exit with the status it\n\
305 -h, --help Show this help text.\n\
306 -v, --version Show version string.\n\
307 -u, --usage Show a terse usage summary.\n\
309 -s, --signal=SIG Send signal SIG to the command.\n\
313 /*----- Timeout handling --------------------------------------------------*/
315 /* --- @timeout@ --- *
317 * The first time, we send the signal requested by the caller. Then we wait
318 * five seconds for the child to die, and send @SIGKILL@. If that still
319 * doesn't help, then we just give up. It's not like there's anything else
320 * we can do which is likely to help. And it's not like the process is going
321 * to be doing anything else in user mode ever again.
331 static void timeout(struct timeval *now, void *p)
333 struct timeout *t = p;
338 moan("timed out: killing child process");
339 kill(-t->kid, t->sig);
342 moan("child hasn't responded: killing harder");
343 kill(-t->kid, SIGKILL);
346 moan("child still undead: giving up");
350 TV_ADDL(&tv, now, 5, 0);
351 sel_addtimer(&sel, &t->t, &tv, timeout, t);
355 /*----- Signal handling ---------------------------------------------------*/
357 /* --- @sigchld@ --- *
359 * If it's our child that died, fetch its exit status and stop.
367 static void sigchld(int sig, void *p)
369 struct sigchld *s = p;
373 if ((pid = waitpid(s->kid, &rc, WNOHANG)) < 0)
374 die(254, "waitpid failed: %s", strerror(errno));
381 /* --- @sigpropagate@ --- *
383 * Propagate various signals to the child process group and then maybe act on
387 static void sigpropagate(int sig, void *p)
389 struct sigchld *s = p;
393 case SIGTSTP: raise(SIGSTOP); break;
397 #define PROPAGATE_SIGNALS(_) \
398 _(TSTP) _(CONT) _(INT) _(HUP) _(QUIT)
400 /*----- Main program ------------------------------------------------------*/
404 int main(int argc, char *const argv[])
408 struct timeval now, tv;
412 #define DEFSIG(tag) sig sig_##tag;
413 PROPAGATE_SIGNALS(DEFSIG)
418 /* --- Option parsing --- */
423 static const struct option opts[] = {
424 { "help", 0, 0, 'h' },
425 { "version", 0, 0, 'v' },
426 { "usage", 0, 0, 'u' },
427 { "signal", OPTF_ARGREQ, 0, 's' },
431 int i = mdwopt(argc, argv, "+hvus:", opts, 0, 0, 0);
434 case 'h': help(stdout); exit(0);
435 case 'v': version(stdout); exit(0);
436 case 'u': usage(stdout); exit(0);
438 if ((signo = namesig(optarg)) < 0)
439 die(253, "bad signal spec `%s'", optarg);
441 default: f |= F_BOGUS; break;
444 argc -= optind; argv += optind;
445 if ((f & F_BOGUS) || argc < 2) { usage(stderr); exit(253); }
446 strtotime(argv[0], &tv);
448 /* --- Get things set up --- */
453 /* --- Set up signal handling --- *
455 * Doing anything with asynchronous signals is a mug's game, so we bring
456 * them in-band. Do this before starting the child process, because
457 * otherwise we might miss an immediate @SIGCHLD@.
462 sig_add(&sig_CHLD, SIGCHLD, sigchld, &sc);
463 #define ADDSIG(tag) sig_add(&sig_##tag, SIG##tag, sigpropagate, &sc);
464 PROPAGATE_SIGNALS(ADDSIG)
467 /* --- Now start the child process --- */
469 if ((kid = fork()) < 0) die(2, "fork failed: %s", strerror(errno));
472 execvp(argv[1], argv + 1);
473 die(252, "exec(%s) failed: %s", argv[1], strerror(errno));
477 /* --- Set up the timer --- */
482 gettimeofday(&now, 0);
483 TV_ADD(&tv, &now, &tv);
484 sel_addtimer(&sel, &to.t, &tv, timeout, &to);
486 /* --- Main @select@ loop */
488 while (state == ST_WAIT) {
489 if (sel_select(&sel)) {
490 if (errno == EINTR) continue;
491 die(254, "select failed: %s", strerror(errno));
495 /* --- Check and translate the exit code --- */
501 if (WIFEXITED(sc.rc))
502 exit(WEXITSTATUS(sc.rc));
503 else if (WIFSIGNALED(sc.rc))
504 exit(128 | WTERMSIG(sc.rc));
508 moan("FATAL: unexpected state %d", state);
513 /*----- That's all, folks -------------------------------------------------*/