xref: /freebsd/bin/pkill/pkill.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*	$NetBSD: pkill.c,v 1.16 2005/10/10 22:13:20 kleink Exp $	*/
2 
3 /*-
4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
5  * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
6  * All rights reserved.
7  *
8  * This code is derived from software contributed to The NetBSD Foundation
9  * by Andrew Doran.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the NetBSD
22  *	Foundation, Inc. and its contributors.
23  * 4. Neither the name of The NetBSD Foundation nor the names of its
24  *    contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/types.h>
44 #include <sys/param.h>
45 #include <sys/sysctl.h>
46 #include <sys/proc.h>
47 #include <sys/queue.h>
48 #include <sys/stat.h>
49 #include <sys/time.h>
50 #include <sys/user.h>
51 
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <limits.h>
55 #include <paths.h>
56 #include <string.h>
57 #include <unistd.h>
58 #include <signal.h>
59 #include <regex.h>
60 #include <ctype.h>
61 #include <fcntl.h>
62 #include <kvm.h>
63 #include <err.h>
64 #include <pwd.h>
65 #include <grp.h>
66 #include <errno.h>
67 #include <locale.h>
68 
69 #define	STATUS_MATCH	0
70 #define	STATUS_NOMATCH	1
71 #define	STATUS_BADUSAGE	2
72 #define	STATUS_ERROR	3
73 
74 #define	MIN_PID	5
75 #define	MAX_PID	99999
76 
77 /* Ignore system-processes (if '-S' flag is not specified) and myself. */
78 #define	PSKIP(kp)	((kp)->ki_pid == mypid ||			\
79 			 (!kthreads && ((kp)->ki_flag & P_KTHREAD) != 0))
80 
81 enum listtype {
82 	LT_GENERIC,
83 	LT_USER,
84 	LT_GROUP,
85 	LT_TTY,
86 	LT_PGRP,
87 	LT_JID,
88 	LT_SID
89 };
90 
91 struct list {
92 	SLIST_ENTRY(list) li_chain;
93 	long	li_number;
94 };
95 
96 SLIST_HEAD(listhead, list);
97 
98 static struct kinfo_proc *plist;
99 static char	*selected;
100 static const char *delim = "\n";
101 static int	nproc;
102 static int	pgrep;
103 static int	signum = SIGTERM;
104 static int	newest;
105 static int	oldest;
106 static int	interactive;
107 static int	inverse;
108 static int	longfmt;
109 static int	matchargs;
110 static int	fullmatch;
111 static int	kthreads;
112 static int	cflags = REG_EXTENDED;
113 static kvm_t	*kd;
114 static pid_t	mypid;
115 
116 static struct listhead euidlist = SLIST_HEAD_INITIALIZER(list);
117 static struct listhead ruidlist = SLIST_HEAD_INITIALIZER(list);
118 static struct listhead rgidlist = SLIST_HEAD_INITIALIZER(list);
119 static struct listhead pgrplist = SLIST_HEAD_INITIALIZER(list);
120 static struct listhead ppidlist = SLIST_HEAD_INITIALIZER(list);
121 static struct listhead tdevlist = SLIST_HEAD_INITIALIZER(list);
122 static struct listhead sidlist = SLIST_HEAD_INITIALIZER(list);
123 static struct listhead jidlist = SLIST_HEAD_INITIALIZER(list);
124 
125 static void	usage(void) __attribute__((__noreturn__));
126 static int	killact(const struct kinfo_proc *);
127 static int	grepact(const struct kinfo_proc *);
128 static void	makelist(struct listhead *, enum listtype, char *);
129 static int	takepid(const char *, int);
130 
131 int
132 main(int argc, char **argv)
133 {
134 	char buf[_POSIX2_LINE_MAX], *mstr, **pargv, *p, *q, *pidfile;
135 	const char *execf, *coref;
136 	int debug_opt;
137 	int i, ch, bestidx, rv, criteria, pidfromfile, pidfilelock;
138 	size_t jsz;
139 	int (*action)(const struct kinfo_proc *);
140 	struct kinfo_proc *kp;
141 	struct list *li;
142 	struct timeval best_tval;
143 	regex_t reg;
144 	regmatch_t regmatch;
145 
146 	setlocale(LC_ALL, "");
147 
148 	if (strcmp(getprogname(), "pgrep") == 0) {
149 		action = grepact;
150 		pgrep = 1;
151 	} else {
152 		action = killact;
153 		p = argv[1];
154 
155 		if (argc > 1 && p[0] == '-') {
156 			p++;
157 			i = (int)strtol(p, &q, 10);
158 			if (*q == '\0') {
159 				signum = i;
160 				argv++;
161 				argc--;
162 			} else {
163 				if (strncasecmp(p, "sig", 3) == 0)
164 					p += 3;
165 				for (i = 1; i < NSIG; i++)
166 					if (strcasecmp(sys_signame[i], p) == 0)
167 						break;
168 				if (i != NSIG) {
169 					signum = i;
170 					argv++;
171 					argc--;
172 				}
173 			}
174 		}
175 	}
176 
177 	criteria = 0;
178 	debug_opt = 0;
179 	pidfile = NULL;
180 	pidfilelock = 0;
181 	execf = coref = _PATH_DEVNULL;
182 
183 	while ((ch = getopt(argc, argv, "DF:G:ILM:N:P:SU:d:fg:ij:lnos:t:u:vx")) != -1)
184 		switch (ch) {
185 		case 'D':
186 			debug_opt++;
187 			break;
188 		case 'F':
189 			pidfile = optarg;
190 			criteria = 1;
191 			break;
192 		case 'G':
193 			makelist(&rgidlist, LT_GROUP, optarg);
194 			criteria = 1;
195 			break;
196 		case 'I':
197 			if (pgrep)
198 				usage();
199 			interactive = 1;
200 			break;
201 		case 'L':
202 			pidfilelock = 1;
203 			break;
204 		case 'M':
205 			coref = optarg;
206 			break;
207 		case 'N':
208 			execf = optarg;
209 			break;
210 		case 'P':
211 			makelist(&ppidlist, LT_GENERIC, optarg);
212 			criteria = 1;
213 			break;
214 		case 'S':
215 			if (!pgrep)
216 				usage();
217 			kthreads = 1;
218 			break;
219 		case 'U':
220 			makelist(&ruidlist, LT_USER, optarg);
221 			criteria = 1;
222 			break;
223 		case 'd':
224 			if (!pgrep)
225 				usage();
226 			delim = optarg;
227 			break;
228 		case 'f':
229 			matchargs = 1;
230 			break;
231 		case 'g':
232 			makelist(&pgrplist, LT_PGRP, optarg);
233 			criteria = 1;
234 			break;
235 		case 'i':
236 			cflags |= REG_ICASE;
237 			break;
238 		case 'j':
239 			makelist(&jidlist, LT_JID, optarg);
240 			criteria = 1;
241 			break;
242 		case 'l':
243 			if (!pgrep)
244 				usage();
245 			longfmt = 1;
246 			break;
247 		case 'n':
248 			newest = 1;
249 			criteria = 1;
250 			break;
251 		case 'o':
252 			oldest = 1;
253 			criteria = 1;
254 			break;
255 		case 's':
256 			makelist(&sidlist, LT_SID, optarg);
257 			criteria = 1;
258 			break;
259 		case 't':
260 			makelist(&tdevlist, LT_TTY, optarg);
261 			criteria = 1;
262 			break;
263 		case 'u':
264 			makelist(&euidlist, LT_USER, optarg);
265 			criteria = 1;
266 			break;
267 		case 'v':
268 			inverse = 1;
269 			break;
270 		case 'x':
271 			fullmatch = 1;
272 			break;
273 		default:
274 			usage();
275 			/* NOTREACHED */
276 		}
277 
278 	argc -= optind;
279 	argv += optind;
280 	if (argc != 0)
281 		criteria = 1;
282 	if (!criteria)
283 		usage();
284 	if (newest && oldest)
285 		errx(STATUS_ERROR, "Options -n and -o are mutually exclusive");
286 	if (pidfile != NULL)
287 		pidfromfile = takepid(pidfile, pidfilelock);
288 	else {
289 		if (pidfilelock) {
290 			errx(STATUS_ERROR,
291 			    "Option -L doesn't make sense without -F");
292 		}
293 		pidfromfile = -1;
294 	}
295 
296 	mypid = getpid();
297 
298 	/*
299 	 * Retrieve the list of running processes from the kernel.
300 	 */
301 	kd = kvm_openfiles(execf, coref, NULL, O_RDONLY, buf);
302 	if (kd == NULL)
303 		errx(STATUS_ERROR, "Cannot open kernel files (%s)", buf);
304 
305 	/*
306 	 * Use KERN_PROC_PROC instead of KERN_PROC_ALL, since we
307 	 * just want processes and not individual kernel threads.
308 	 */
309 	plist = kvm_getprocs(kd, KERN_PROC_PROC, 0, &nproc);
310 	if (plist == NULL) {
311 		errx(STATUS_ERROR, "Cannot get process list (%s)",
312 		    kvm_geterr(kd));
313 	}
314 
315 	/*
316 	 * Allocate memory which will be used to keep track of the
317 	 * selection.
318 	 */
319 	if ((selected = malloc(nproc)) == NULL) {
320 		err(STATUS_ERROR, "Cannot allocate memory for %d processes",
321 		    nproc);
322 	}
323 	memset(selected, 0, nproc);
324 
325 	/*
326 	 * Refine the selection.
327 	 */
328 	for (; *argv != NULL; argv++) {
329 		if ((rv = regcomp(&reg, *argv, cflags)) != 0) {
330 			regerror(rv, &reg, buf, sizeof(buf));
331 			errx(STATUS_BADUSAGE,
332 			    "Cannot compile regular expression `%s' (%s)",
333 			    *argv, buf);
334 		}
335 
336 		for (i = 0, kp = plist; i < nproc; i++, kp++) {
337 			if (PSKIP(kp)) {
338 				if (debug_opt > 0)
339 				    fprintf(stderr, "* Skipped %5d %3d %s\n",
340 					kp->ki_pid, kp->ki_uid, kp->ki_comm);
341 				continue;
342 			}
343 
344 			if (matchargs &&
345 			    (pargv = kvm_getargv(kd, kp, 0)) != NULL) {
346 				jsz = 0;
347 				while (jsz < sizeof(buf) && *pargv != NULL) {
348 					jsz += snprintf(buf + jsz,
349 					    sizeof(buf) - jsz,
350 					    pargv[1] != NULL ? "%s " : "%s",
351 					    pargv[0]);
352 					pargv++;
353 				}
354 				mstr = buf;
355 			} else
356 				mstr = kp->ki_comm;
357 
358 			rv = regexec(&reg, mstr, 1, &regmatch, 0);
359 			if (rv == 0) {
360 				if (fullmatch) {
361 					if (regmatch.rm_so == 0 &&
362 					    regmatch.rm_eo ==
363 					    (off_t)strlen(mstr))
364 						selected[i] = 1;
365 				} else
366 					selected[i] = 1;
367 			} else if (rv != REG_NOMATCH) {
368 				regerror(rv, &reg, buf, sizeof(buf));
369 				errx(STATUS_ERROR,
370 				    "Regular expression evaluation error (%s)",
371 				    buf);
372 			}
373 			if (debug_opt > 1) {
374 				const char *rv_res = "NoMatch";
375 				if (selected[i])
376 					rv_res = "Matched";
377 				fprintf(stderr, "* %s %5d %3d %s\n", rv_res,
378 				    kp->ki_pid, kp->ki_uid, mstr);
379 			}
380 		}
381 
382 		regfree(&reg);
383 	}
384 
385 	for (i = 0, kp = plist; i < nproc; i++, kp++) {
386 		if (PSKIP(kp))
387 			continue;
388 
389 		if (pidfromfile >= 0 && kp->ki_pid != pidfromfile) {
390 			selected[i] = 0;
391 			continue;
392 		}
393 
394 		SLIST_FOREACH(li, &ruidlist, li_chain)
395 			if (kp->ki_ruid == (uid_t)li->li_number)
396 				break;
397 		if (SLIST_FIRST(&ruidlist) != NULL && li == NULL) {
398 			selected[i] = 0;
399 			continue;
400 		}
401 
402 		SLIST_FOREACH(li, &rgidlist, li_chain)
403 			if (kp->ki_rgid == (gid_t)li->li_number)
404 				break;
405 		if (SLIST_FIRST(&rgidlist) != NULL && li == NULL) {
406 			selected[i] = 0;
407 			continue;
408 		}
409 
410 		SLIST_FOREACH(li, &euidlist, li_chain)
411 			if (kp->ki_uid == (uid_t)li->li_number)
412 				break;
413 		if (SLIST_FIRST(&euidlist) != NULL && li == NULL) {
414 			selected[i] = 0;
415 			continue;
416 		}
417 
418 		SLIST_FOREACH(li, &ppidlist, li_chain)
419 			if (kp->ki_ppid == (pid_t)li->li_number)
420 				break;
421 		if (SLIST_FIRST(&ppidlist) != NULL && li == NULL) {
422 			selected[i] = 0;
423 			continue;
424 		}
425 
426 		SLIST_FOREACH(li, &pgrplist, li_chain)
427 			if (kp->ki_pgid == (pid_t)li->li_number)
428 				break;
429 		if (SLIST_FIRST(&pgrplist) != NULL && li == NULL) {
430 			selected[i] = 0;
431 			continue;
432 		}
433 
434 		SLIST_FOREACH(li, &tdevlist, li_chain) {
435 			if (li->li_number == -1 &&
436 			    (kp->ki_flag & P_CONTROLT) == 0)
437 				break;
438 			if (kp->ki_tdev == (dev_t)li->li_number)
439 				break;
440 		}
441 		if (SLIST_FIRST(&tdevlist) != NULL && li == NULL) {
442 			selected[i] = 0;
443 			continue;
444 		}
445 
446 		SLIST_FOREACH(li, &sidlist, li_chain)
447 			if (kp->ki_sid == (pid_t)li->li_number)
448 				break;
449 		if (SLIST_FIRST(&sidlist) != NULL && li == NULL) {
450 			selected[i] = 0;
451 			continue;
452 		}
453 
454 		SLIST_FOREACH(li, &jidlist, li_chain) {
455 			/* A particular jail ID, including 0 (not in jail) */
456 			if (kp->ki_jid == (int)li->li_number)
457 				break;
458 			/* Any jail */
459 			if (kp->ki_jid > 0 && li->li_number == -1)
460 				break;
461 		}
462 		if (SLIST_FIRST(&jidlist) != NULL && li == NULL) {
463 			selected[i] = 0;
464 			continue;
465 		}
466 
467 		if (argc == 0)
468 			selected[i] = 1;
469 	}
470 
471 	if (newest || oldest) {
472 		best_tval.tv_sec = 0;
473 		best_tval.tv_usec = 0;
474 		bestidx = -1;
475 
476 		for (i = 0, kp = plist; i < nproc; i++, kp++) {
477 			if (!selected[i])
478 				continue;
479 			if (bestidx == -1) {
480 				/* The first entry of the list which matched. */
481 				;
482 			} else if (timercmp(&kp->ki_start, &best_tval, >)) {
483 				/* This entry is newer than previous "best". */
484 				if (oldest)	/* but we want the oldest */
485 					continue;
486 			} else {
487 				/* This entry is older than previous "best". */
488 				if (newest)	/* but we want the newest */
489 					continue;
490 			}
491 			/* This entry is better than previous "best" entry. */
492 			best_tval.tv_sec = kp->ki_start.tv_sec;
493 			best_tval.tv_usec = kp->ki_start.tv_usec;
494 			bestidx = i;
495 		}
496 
497 		memset(selected, 0, nproc);
498 		if (bestidx != -1)
499 			selected[bestidx] = 1;
500 	}
501 
502 	/*
503 	 * Take the appropriate action for each matched process, if any.
504 	 */
505 	for (i = 0, rv = 0, kp = plist; i < nproc; i++, kp++) {
506 		if (PSKIP(kp))
507 			continue;
508 		if (selected[i]) {
509 			if (inverse)
510 				continue;
511 		} else if (!inverse)
512 			continue;
513 		rv |= (*action)(kp);
514 	}
515 
516 	exit(rv ? STATUS_MATCH : STATUS_NOMATCH);
517 }
518 
519 static void
520 usage(void)
521 {
522 	const char *ustr;
523 
524 	if (pgrep)
525 		ustr = "[-LSfilnovx] [-d delim]";
526 	else
527 		ustr = "[-signal] [-ILfinovx]";
528 
529 	fprintf(stderr,
530 		"usage: %s %s [-F pidfile] [-G gid] [-M core] [-N system]\n"
531 		"             [-P ppid] [-U uid] [-g pgrp] [-j jid] [-s sid]\n"
532 		"             [-t tty] [-u euid] pattern ...\n", getprogname(),
533 		ustr);
534 
535 	exit(STATUS_BADUSAGE);
536 }
537 
538 static void
539 show_process(const struct kinfo_proc *kp)
540 {
541 	char **argv;
542 
543 	if ((longfmt || !pgrep) && matchargs &&
544 	    (argv = kvm_getargv(kd, kp, 0)) != NULL) {
545 		printf("%d ", (int)kp->ki_pid);
546 		for (; *argv != NULL; argv++) {
547 			printf("%s", *argv);
548 			if (argv[1] != NULL)
549 				putchar(' ');
550 		}
551 	} else if (longfmt || !pgrep)
552 		printf("%d %s", (int)kp->ki_pid, kp->ki_comm);
553 	else
554 		printf("%d", (int)kp->ki_pid);
555 }
556 
557 static int
558 killact(const struct kinfo_proc *kp)
559 {
560 	int ch, first;
561 
562 	if (interactive) {
563 		/*
564 		 * Be careful, ask before killing.
565 		 */
566 		printf("kill ");
567 		show_process(kp);
568 		printf("? ");
569 		fflush(stdout);
570 		first = ch = getchar();
571 		while (ch != '\n' && ch != EOF)
572 			ch = getchar();
573 		if (first != 'y' && first != 'Y')
574 			return (1);
575 	}
576 	if (kill(kp->ki_pid, signum) == -1) {
577 		/*
578 		 * Check for ESRCH, which indicates that the process
579 		 * disappeared between us matching it and us
580 		 * signalling it; don't issue a warning about it.
581 		 */
582 		if (errno != ESRCH)
583 			warn("signalling pid %d", (int)kp->ki_pid);
584 		/*
585 		 * Return 0 to indicate that the process should not be
586 		 * considered a match, since we didn't actually get to
587 		 * signal it.
588 		 */
589 		return (0);
590 	}
591 	return (1);
592 }
593 
594 static int
595 grepact(const struct kinfo_proc *kp)
596 {
597 
598 	show_process(kp);
599 	printf("%s", delim);
600 	return (1);
601 }
602 
603 static void
604 makelist(struct listhead *head, enum listtype type, char *src)
605 {
606 	struct list *li;
607 	struct passwd *pw;
608 	struct group *gr;
609 	struct stat st;
610 	const char *cp;
611 	char *sp, *ep, buf[MAXPATHLEN];
612 	int empty;
613 
614 	empty = 1;
615 
616 	while ((sp = strsep(&src, ",")) != NULL) {
617 		if (*sp == '\0')
618 			usage();
619 
620 		if ((li = malloc(sizeof(*li))) == NULL) {
621 			err(STATUS_ERROR, "Cannot allocate %zu bytes",
622 			    sizeof(*li));
623 		}
624 
625 		SLIST_INSERT_HEAD(head, li, li_chain);
626 		empty = 0;
627 
628 		li->li_number = (uid_t)strtol(sp, &ep, 0);
629 		if (*ep == '\0') {
630 			switch (type) {
631 			case LT_PGRP:
632 				if (li->li_number == 0)
633 					li->li_number = getpgrp();
634 				break;
635 			case LT_SID:
636 				if (li->li_number == 0)
637 					li->li_number = getsid(mypid);
638 				break;
639 			case LT_JID:
640 				if (li->li_number < 0)
641 					errx(STATUS_BADUSAGE,
642 					     "Negative jail ID `%s'", sp);
643 				/* For compatibility with old -j */
644 				if (li->li_number == 0)
645 					li->li_number = -1;	/* any jail */
646 				break;
647 			case LT_TTY:
648 				usage();
649 				/* NOTREACHED */
650 			default:
651 				break;
652 			}
653 			continue;
654 		}
655 
656 		switch (type) {
657 		case LT_USER:
658 			if ((pw = getpwnam(sp)) == NULL)
659 				errx(STATUS_BADUSAGE, "Unknown user `%s'", sp);
660 			li->li_number = pw->pw_uid;
661 			break;
662 		case LT_GROUP:
663 			if ((gr = getgrnam(sp)) == NULL)
664 				errx(STATUS_BADUSAGE, "Unknown group `%s'", sp);
665 			li->li_number = gr->gr_gid;
666 			break;
667 		case LT_TTY:
668 			if (strcmp(sp, "-") == 0) {
669 				li->li_number = -1;
670 				break;
671 			} else if (strcmp(sp, "co") == 0) {
672 				cp = "console";
673 			} else {
674 				cp = sp;
675 			}
676 
677 			snprintf(buf, sizeof(buf), _PATH_DEV "%s", cp);
678 			if (stat(buf, &st) != -1)
679 				goto foundtty;
680 
681 			snprintf(buf, sizeof(buf), _PATH_DEV "tty%s", cp);
682 			if (stat(buf, &st) != -1)
683 				goto foundtty;
684 
685 			if (errno == ENOENT)
686 				errx(STATUS_BADUSAGE, "No such tty: `%s'", sp);
687 			err(STATUS_ERROR, "Cannot access `%s'", sp);
688 
689 foundtty:		if ((st.st_mode & S_IFCHR) == 0)
690 				errx(STATUS_BADUSAGE, "Not a tty: `%s'", sp);
691 
692 			li->li_number = st.st_rdev;
693 			break;
694 		case LT_JID:
695 			if (strcmp(sp, "none") == 0)
696 				li->li_number = 0;
697 			else if (strcmp(sp, "any") == 0)
698 				li->li_number = -1;
699 			else if (*ep != '\0')
700 				errx(STATUS_BADUSAGE,
701 				     "Invalid jail ID `%s'", sp);
702 			break;
703 		default:
704 			usage();
705 		}
706 	}
707 
708 	if (empty)
709 		usage();
710 }
711 
712 static int
713 takepid(const char *pidfile, int pidfilelock)
714 {
715 	char *endp, line[BUFSIZ];
716 	FILE *fh;
717 	long rval;
718 
719 	fh = fopen(pidfile, "r");
720 	if (fh == NULL)
721 		err(STATUS_ERROR, "Cannot open pidfile `%s'", pidfile);
722 
723 	if (pidfilelock) {
724 		/*
725 		 * If we can lock pidfile, this means that daemon is not
726 		 * running, so would be better not to kill some random process.
727 		 */
728 		if (flock(fileno(fh), LOCK_EX | LOCK_NB) == 0) {
729 			(void)fclose(fh);
730 			errx(STATUS_ERROR, "File '%s' can be locked", pidfile);
731 		} else {
732 			if (errno != EWOULDBLOCK) {
733 				errx(STATUS_ERROR,
734 				    "Error while locking file '%s'", pidfile);
735 			}
736 		}
737 	}
738 
739 	if (fgets(line, sizeof(line), fh) == NULL) {
740 		if (feof(fh)) {
741 			(void)fclose(fh);
742 			errx(STATUS_ERROR, "Pidfile `%s' is empty", pidfile);
743 		}
744 		(void)fclose(fh);
745 		err(STATUS_ERROR, "Cannot read from pid file `%s'", pidfile);
746 	}
747 	(void)fclose(fh);
748 
749 	rval = strtol(line, &endp, 10);
750 	if (*endp != '\0' && !isspace((unsigned char)*endp))
751 		errx(STATUS_ERROR, "Invalid pid in file `%s'", pidfile);
752 	else if (rval < MIN_PID || rval > MAX_PID)
753 		errx(STATUS_ERROR, "Invalid pid in file `%s'", pidfile);
754 	return (rval);
755 }
756