xref: /freebsd/usr.sbin/daemon/daemon.c (revision 927358dd98cb902160093e0dc0bac002d6b43858)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1999 Berkeley Software Design, Inc. All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. Berkeley Software Design Inc's name may not be used to endorse or
15  *    promote products derived from this software without specific prior
16  *    written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  *	From BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include <sys/param.h>
37 #include <sys/mman.h>
38 #include <sys/wait.h>
39 
40 #include <fcntl.h>
41 #include <err.h>
42 #include <errno.h>
43 #include <getopt.h>
44 #include <libutil.h>
45 #include <login_cap.h>
46 #include <paths.h>
47 #include <pwd.h>
48 #include <signal.h>
49 #include <stdio.h>
50 #include <stdbool.h>
51 #include <stdlib.h>
52 #include <unistd.h>
53 #include <string.h>
54 #include <strings.h>
55 #define SYSLOG_NAMES
56 #include <syslog.h>
57 #include <time.h>
58 #include <assert.h>
59 
60 #define LBUF_SIZE 4096
61 
62 struct daemon_state {
63 	int pipe_fd[2];
64 	const char *child_pidfile;
65 	const char *parent_pidfile;
66 	const char *output_filename;
67 	const char *syslog_tag;
68 	const char *title;
69 	const char *user;
70 	struct pidfh *parent_pidfh;
71 	struct pidfh *child_pidfh;
72 	int keep_cur_workdir;
73 	int restart_delay;
74 	int stdmask;
75 	int syslog_priority;
76 	int syslog_facility;
77 	int keep_fds_open;
78 	int output_fd;
79 	bool supervision_enabled;
80 	bool child_eof;
81 	bool restart_enabled;
82 	bool syslog_enabled;
83 	bool log_reopen;
84 };
85 
86 static void restrict_process(const char *);
87 static void handle_term(int);
88 static void handle_chld(int);
89 static void handle_hup(int);
90 static int  open_log(const char *);
91 static void reopen_log(struct daemon_state *);
92 static bool listen_child(int, struct daemon_state *);
93 static int  get_log_mapping(const char *, const CODE *);
94 static void open_pid_files(struct daemon_state *);
95 static void do_output(const unsigned char *, size_t, struct daemon_state *);
96 static void daemon_sleep(time_t, long);
97 static void daemon_state_init(struct daemon_state *);
98 static void daemon_terminate(struct daemon_state *);
99 
100 static volatile sig_atomic_t terminate = 0;
101 static volatile sig_atomic_t child_gone = 0;
102 static volatile sig_atomic_t pid = 0;
103 static volatile sig_atomic_t do_log_reopen = 0;
104 
105 static const char shortopts[] = "+cfHSp:P:ru:o:s:l:t:m:R:T:h";
106 
107 static const struct option longopts[] = {
108         { "change-dir",         no_argument,            NULL,           'c' },
109         { "close-fds",          no_argument,            NULL,           'f' },
110         { "sighup",             no_argument,            NULL,           'H' },
111         { "syslog",             no_argument,            NULL,           'S' },
112         { "output-file",        required_argument,      NULL,           'o' },
113         { "output-mask",        required_argument,      NULL,           'm' },
114         { "child-pidfile",      required_argument,      NULL,           'p' },
115         { "supervisor-pidfile", required_argument,      NULL,           'P' },
116         { "restart",            no_argument,            NULL,           'r' },
117         { "restart-delay",      required_argument,      NULL,           'R' },
118         { "title",              required_argument,      NULL,           't' },
119         { "user",               required_argument,      NULL,           'u' },
120         { "syslog-priority",    required_argument,      NULL,           's' },
121         { "syslog-facility",    required_argument,      NULL,           'l' },
122         { "syslog-tag",         required_argument,      NULL,           'T' },
123         { "help",               no_argument,            NULL,           'h' },
124         { NULL,                 0,                      NULL,            0  }
125 };
126 
127 static _Noreturn void
128 usage(int exitcode)
129 {
130 	(void)fprintf(stderr,
131 	    "usage: daemon [-cfHrS] [-p child_pidfile] [-P supervisor_pidfile]\n"
132 	    "              [-u user] [-o output_file] [-t title]\n"
133 	    "              [-l syslog_facility] [-s syslog_priority]\n"
134 	    "              [-T syslog_tag] [-m output_mask] [-R restart_delay_secs]\n"
135 	    "command arguments ...\n");
136 
137 	(void)fprintf(stderr,
138 	    "  --change-dir         -c         Change the current working directory to root\n"
139 	    "  --close-fds          -f         Set stdin, stdout, stderr to /dev/null\n"
140 	    "  --sighup             -H         Close and re-open output file on SIGHUP\n"
141 	    "  --syslog             -S         Send output to syslog\n"
142 	    "  --output-file        -o <file>  Append output of the child process to file\n"
143 	    "  --output-mask        -m <mask>  What to send to syslog/file\n"
144 	    "                                  1=stdout, 2=stderr, 3=both\n"
145 	    "  --child-pidfile      -p <file>  Write PID of the child process to file\n"
146 	    "  --supervisor-pidfile -P <file>  Write PID of the supervisor process to file\n"
147 	    "  --restart            -r         Restart child if it terminates (1 sec delay)\n"
148 	    "  --restart-delay      -R <N>     Restart child if it terminates after N sec\n"
149 	    "  --title              -t <title> Set the title of the supervisor process\n"
150 	    "  --user               -u <user>  Drop privileges, run as given user\n"
151 	    "  --syslog-priority    -s <prio>  Set syslog priority\n"
152 	    "  --syslog-facility    -l <flty>  Set syslog facility\n"
153 	    "  --syslog-tag         -T <tag>   Set syslog tag\n"
154 	    "  --help               -h         Show this help\n");
155 
156 	exit(exitcode);
157 }
158 
159 int
160 main(int argc, char *argv[])
161 {
162 	char *p = NULL;
163 	int ch = 0;
164 	struct daemon_state state;
165 	sigset_t mask_orig;
166 	sigset_t mask_read;
167 	sigset_t mask_term;
168 	sigset_t mask_susp;
169 
170 	daemon_state_init(&state);
171 	sigemptyset(&mask_susp);
172 	sigemptyset(&mask_read);
173 	sigemptyset(&mask_term);
174 	sigemptyset(&mask_orig);
175 
176 	/*
177 	 * Supervision mode is enabled if one of the following options are used:
178 	 * --child-pidfile -p
179 	 * --supervisor-pidfile -P
180 	 * --restart -r / --restart-delay -R
181 	 * --syslog -S
182 	 * --syslog-facility -l
183 	 * --syslog-priority -s
184 	 * --syslog-tag -T
185 	 *
186 	 * In supervision mode daemon executes the command in a forked process
187 	 * and observes the child by waiting for SIGCHILD. In supervision mode
188 	 * daemon must never exit before the child, this is necessary  to prevent
189 	 * orphaning the child and leaving a stale pid file.
190 	 * To achieve this daemon catches SIGTERM and
191 	 * forwards it to the child, expecting to get SIGCHLD eventually.
192 	 */
193 	while ((ch = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1) {
194 		switch (ch) {
195 		case 'c':
196 			state.keep_cur_workdir = 0;
197 			break;
198 		case 'f':
199 			state.keep_fds_open = 0;
200 			break;
201 		case 'H':
202 			state.log_reopen = true;
203 			break;
204 		case 'l':
205 			state.syslog_facility = get_log_mapping(optarg,
206 			    facilitynames);
207 			if (state.syslog_facility == -1) {
208 				errx(5, "unrecognized syslog facility");
209 			}
210 			state.syslog_enabled = true;
211 			state.supervision_enabled = true;
212 			break;
213 		case 'm':
214 			state.stdmask = strtol(optarg, &p, 10);
215 			if (p == optarg || state.stdmask < 0 || state.stdmask > 3) {
216 				errx(6, "unrecognized listening mask");
217 			}
218 			break;
219 		case 'o':
220 			state.output_filename = optarg;
221 			/*
222 			 * TODO: setting output filename doesn't have to turn
223 			 * the supervision mode on. For non-supervised mode
224 			 * daemon could open the specified file and set it's
225 			 * descriptor as both stderr and stout before execve()
226 			 */
227 			state.supervision_enabled = true;
228 			break;
229 		case 'p':
230 			state.child_pidfile = optarg;
231 			state.supervision_enabled = true;
232 			break;
233 		case 'P':
234 			state.parent_pidfile = optarg;
235 			state.supervision_enabled = true;
236 			break;
237 		case 'r':
238 			state.restart_enabled = true;
239 			state.supervision_enabled = true;
240 			break;
241 		case 'R':
242 			state.restart_enabled = true;
243 			state.restart_delay = strtol(optarg, &p, 0);
244 			if (p == optarg || state.restart_delay < 1) {
245 				errx(6, "invalid restart delay");
246 			}
247 			break;
248 		case 's':
249 			state.syslog_priority = get_log_mapping(optarg,
250 			    prioritynames);
251 			if (state.syslog_priority == -1) {
252 				errx(4, "unrecognized syslog priority");
253 			}
254 			state.syslog_enabled = true;
255 			state.supervision_enabled = true;
256 			break;
257 		case 'S':
258 			state.syslog_enabled = true;
259 			state.supervision_enabled = true;
260 			break;
261 		case 't':
262 			state.title = optarg;
263 			break;
264 		case 'T':
265 			state.syslog_tag = optarg;
266 			state.syslog_enabled = true;
267 			state.supervision_enabled = true;
268 			break;
269 		case 'u':
270 			state.user = optarg;
271 			break;
272 		case 'h':
273 			usage(0);
274 			__builtin_unreachable();
275 		default:
276 			usage(1);
277 		}
278 	}
279 	argc -= optind;
280 	argv += optind;
281 
282 	if (argc == 0) {
283 		usage(1);
284 	}
285 
286 	if (!state.title) {
287 		state.title = argv[0];
288 	}
289 
290 	if (state.output_filename) {
291 		state.output_fd = open_log(state.output_filename);
292 		if (state.output_fd == -1) {
293 			err(7, "open");
294 		}
295 	}
296 
297 	if (state.syslog_enabled) {
298 		openlog(state.syslog_tag, LOG_PID | LOG_NDELAY,
299 		    state.syslog_facility);
300 	}
301 
302 	/*
303 	 * Try to open the pidfile before calling daemon(3),
304 	 * to be able to report the error intelligently
305 	 */
306 	open_pid_files(&state);
307 	if (daemon(state.keep_cur_workdir, state.keep_fds_open) == -1) {
308 		warn("daemon");
309 		daemon_terminate(&state);
310 	}
311 	/* Write out parent pidfile if needed. */
312 	pidfile_write(state.parent_pidfh);
313 
314 	if (state.supervision_enabled) {
315 		struct sigaction act_term = { 0 };
316 		struct sigaction act_chld = { 0 };
317 		struct sigaction act_hup = { 0 };
318 
319 		/* Avoid PID racing with SIGCHLD and SIGTERM. */
320 		act_term.sa_handler = handle_term;
321 		sigemptyset(&act_term.sa_mask);
322 		sigaddset(&act_term.sa_mask, SIGCHLD);
323 
324 		act_chld.sa_handler = handle_chld;
325 		sigemptyset(&act_chld.sa_mask);
326 		sigaddset(&act_chld.sa_mask, SIGTERM);
327 
328 		act_hup.sa_handler = handle_hup;
329 		sigemptyset(&act_hup.sa_mask);
330 
331 		/* Block these when avoiding racing before sigsuspend(). */
332 		sigaddset(&mask_susp, SIGTERM);
333 		sigaddset(&mask_susp, SIGCHLD);
334 		/* Block SIGTERM when we lack a valid child PID. */
335 		sigaddset(&mask_term, SIGTERM);
336 		/*
337 		 * When reading, we wish to avoid SIGCHLD. SIGTERM
338 		 * has to be caught, otherwise we'll be stuck until
339 		 * the read() returns - if it returns.
340 		 */
341 		sigaddset(&mask_read, SIGCHLD);
342 		/* Block SIGTERM to avoid racing until we have forked. */
343 		if (sigprocmask(SIG_BLOCK, &mask_term, &mask_orig)) {
344 			warn("sigprocmask");
345 			daemon_terminate(&state);
346 		}
347 		if (sigaction(SIGTERM, &act_term, NULL) == -1) {
348 			warn("sigaction");
349 			daemon_terminate(&state);
350 		}
351 		if (sigaction(SIGCHLD, &act_chld, NULL) == -1) {
352 			warn("sigaction");
353 			daemon_terminate(&state);
354 		}
355 		/*
356 		 * Try to protect against pageout kill. Ignore the
357 		 * error, madvise(2) will fail only if a process does
358 		 * not have superuser privileges.
359 		 */
360 		(void)madvise(NULL, 0, MADV_PROTECT);
361 		if (state.log_reopen && state.output_fd >= 0 &&
362 		    sigaction(SIGHUP, &act_hup, NULL) == -1) {
363 			warn("sigaction");
364 			daemon_terminate(&state);
365 		}
366 restart:
367 		if (pipe(state.pipe_fd)) {
368 			err(1, "pipe");
369 		}
370 		/*
371 		 * Spawn a child to exec the command.
372 		 */
373 		child_gone = 0;
374 		pid = fork();
375 	}
376 
377 	/* fork failed, this can only happen when supervision is enabled */
378 	if (pid == -1) {
379 		warn("fork");
380 		daemon_terminate(&state);
381 	}
382 
383 	/* fork succeeded, this is child's branch or supervision is disabled */
384 	if (pid == 0) {
385 		pidfile_write(state.child_pidfh);
386 
387 		if (state.user != NULL) {
388 			restrict_process(state.user);
389 		}
390 		/*
391 		 * In supervision mode, the child gets the original sigmask,
392 		 * and dup'd pipes.
393 		 */
394 		if (state.supervision_enabled) {
395 			close(state.pipe_fd[0]);
396 			if (sigprocmask(SIG_SETMASK, &mask_orig, NULL)) {
397 				err(1, "sigprogmask");
398 			}
399 			if (state.stdmask & STDERR_FILENO) {
400 				if (dup2(state.pipe_fd[1], STDERR_FILENO) == -1) {
401 					err(1, "dup2");
402 				}
403 			}
404 			if (state.stdmask & STDOUT_FILENO) {
405 				if (dup2(state.pipe_fd[1], STDOUT_FILENO) == -1) {
406 					err(1, "dup2");
407 				}
408 			}
409 			if (state.pipe_fd[1] != STDERR_FILENO &&
410 			    state.pipe_fd[1] != STDOUT_FILENO) {
411 				close(state.pipe_fd[1]);
412 			}
413 		}
414 		execvp(argv[0], argv);
415 		/* execvp() failed - report error and exit this process */
416 		err(1, "%s", argv[0]);
417 	}
418 
419 	/*
420 	 * else: pid > 0
421 	 * fork succeeded, this is the parent branch, this can only happen when
422 	 * supervision is enabled
423 	 *
424 	 * Unblock SIGTERM after we know we have a valid child PID to signal.
425 	 */
426 	if (sigprocmask(SIG_UNBLOCK, &mask_term, NULL)) {
427 		warn("sigprocmask");
428 		daemon_terminate(&state);
429 	}
430 	close(state.pipe_fd[1]);
431 	state.pipe_fd[1] = -1;
432 
433 	setproctitle("%s[%d]", state.title, (int)pid);
434 	/*
435 	 * As we have closed the write end of pipe for parent process,
436 	 * we might detect the child's exit by reading EOF. The child
437 	 * might have closed its stdout and stderr, so we must wait for
438 	 * the SIGCHLD to ensure that the process is actually gone.
439 	 */
440 	for (;;) {
441 		/*
442 		 * We block SIGCHLD when listening, but SIGTERM we accept
443 		 * so the read() won't block if we wish to depart.
444 		 *
445 		 * Upon receiving SIGTERM, we have several options after
446 		 * sending the SIGTERM to our child:
447 		 * - read until EOF
448 		 * - read until EOF but only for a while
449 		 * - bail immediately
450 		 *
451 		 * We go for the third, as otherwise we have no guarantee
452 		 * that we won't block indefinitely if the child refuses
453 		 * to depart. To handle the second option, a different
454 		 * approach would be needed (procctl()?)
455 		 */
456 		if (child_gone && state.child_eof) {
457 			break;
458 		}
459 
460 		if (terminate) {
461 			daemon_terminate(&state);
462 		}
463 
464 		if (state.child_eof) {
465 			if (sigprocmask(SIG_BLOCK, &mask_susp, NULL)) {
466 				warn("sigprocmask");
467 				daemon_terminate(&state);
468 			}
469 			while (!terminate && !child_gone) {
470 				sigsuspend(&mask_orig);
471 			}
472 			if (sigprocmask(SIG_UNBLOCK, &mask_susp, NULL)) {
473 				warn("sigprocmask");
474 				daemon_terminate(&state);
475 			}
476 			continue;
477 		}
478 
479 		if (sigprocmask(SIG_BLOCK, &mask_read, NULL)) {
480 			warn("sigprocmask");
481 			daemon_terminate(&state);
482 		}
483 
484 		state.child_eof = !listen_child(state.pipe_fd[0], &state);
485 
486 		if (sigprocmask(SIG_UNBLOCK, &mask_read, NULL)) {
487 			warn("sigprocmask");
488 			daemon_terminate(&state);
489 		}
490 
491 	}
492 	if (state.restart_enabled && !terminate) {
493 		daemon_sleep(state.restart_delay, 0);
494 	}
495 	if (sigprocmask(SIG_BLOCK, &mask_term, NULL)) {
496 		warn("sigprocmask");
497 		daemon_terminate(&state);
498 	}
499 	if (state.restart_enabled && !terminate) {
500 		close(state.pipe_fd[0]);
501 		state.pipe_fd[0] = -1;
502 		goto restart;
503 	}
504 	daemon_terminate(&state);
505 }
506 
507 static void
508 daemon_sleep(time_t secs, long nsecs)
509 {
510 	struct timespec ts = { secs, nsecs };
511 
512 	while (!terminate && nanosleep(&ts, &ts) == -1) {
513 		if (errno != EINTR) {
514 			err(1, "nanosleep");
515 		}
516 	}
517 }
518 
519 static void
520 open_pid_files(struct daemon_state *state)
521 {
522 	pid_t fpid;
523 	int serrno;
524 
525 	if (state->child_pidfile) {
526 		state->child_pidfh = pidfile_open(state->child_pidfile, 0600, &fpid);
527 		if (state->child_pidfh == NULL) {
528 			if (errno == EEXIST) {
529 				errx(3, "process already running, pid: %d",
530 				    fpid);
531 			}
532 			err(2, "pidfile ``%s''", state->child_pidfile);
533 		}
534 	}
535 	/* Do the same for the actual daemon process. */
536 	if (state->parent_pidfile) {
537 		state->parent_pidfh= pidfile_open(state->parent_pidfile, 0600, &fpid);
538 		if (state->parent_pidfh == NULL) {
539 			serrno = errno;
540 			pidfile_remove(state->child_pidfh);
541 			errno = serrno;
542 			if (errno == EEXIST) {
543 				errx(3, "process already running, pid: %d",
544 				     fpid);
545 			}
546 			err(2, "ppidfile ``%s''", state->parent_pidfile);
547 		}
548 	}
549 }
550 
551 static int
552 get_log_mapping(const char *str, const CODE *c)
553 {
554 	const CODE *cp;
555 	for (cp = c; cp->c_name; cp++)
556 		if (strcmp(cp->c_name, str) == 0) {
557 			return cp->c_val;
558 		}
559 	return -1;
560 }
561 
562 static void
563 restrict_process(const char *user)
564 {
565 	struct passwd *pw = NULL;
566 
567 	pw = getpwnam(user);
568 	if (pw == NULL) {
569 		errx(1, "unknown user: %s", user);
570 	}
571 
572 	if (setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0) {
573 		errx(1, "failed to set user environment");
574 	}
575 
576 	setenv("USER", pw->pw_name, 1);
577 	setenv("HOME", pw->pw_dir, 1);
578 	setenv("SHELL", *pw->pw_shell ? pw->pw_shell : _PATH_BSHELL, 1);
579 }
580 
581 /*
582  * We try to collect whole lines terminated by '\n'. Otherwise we collect a
583  * full buffer, and then output it.
584  *
585  * Return value of false is assumed to mean EOF or error, and true indicates to
586  * continue reading.
587  */
588 static bool
589 listen_child(int fd, struct daemon_state *state)
590 {
591 	static unsigned char buf[LBUF_SIZE];
592 	static size_t bytes_read = 0;
593 	int rv;
594 
595 	assert(state != NULL);
596 	assert(bytes_read < LBUF_SIZE - 1);
597 
598 	if (do_log_reopen) {
599 		reopen_log(state);
600 	}
601 	rv = read(fd, buf + bytes_read, LBUF_SIZE - bytes_read - 1);
602 	if (rv > 0) {
603 		unsigned char *cp;
604 
605 		bytes_read += rv;
606 		assert(bytes_read <= LBUF_SIZE - 1);
607 		/* Always NUL-terminate just in case. */
608 		buf[LBUF_SIZE - 1] = '\0';
609 		/*
610 		 * Chomp line by line until we run out of buffer.
611 		 * This does not take NUL characters into account.
612 		 */
613 		while ((cp = memchr(buf, '\n', bytes_read)) != NULL) {
614 			size_t bytes_line = cp - buf + 1;
615 			assert(bytes_line <= bytes_read);
616 			do_output(buf, bytes_line, state);
617 			bytes_read -= bytes_line;
618 			memmove(buf, cp + 1, bytes_read);
619 		}
620 		/* Wait until the buffer is full. */
621 		if (bytes_read < LBUF_SIZE - 1) {
622 			return true;
623 		}
624 		do_output(buf, bytes_read, state);
625 		bytes_read = 0;
626 		return true;
627 	} else if (rv == -1) {
628 		/* EINTR should trigger another read. */
629 		if (errno == EINTR) {
630 			return true;
631 		} else {
632 			warn("read");
633 			return false;
634 		}
635 	}
636 	/* Upon EOF, we have to flush what's left of the buffer. */
637 	if (bytes_read > 0) {
638 		do_output(buf, bytes_read, state);
639 		bytes_read = 0;
640 	}
641 	return false;
642 }
643 
644 /*
645  * The default behavior is to stay silent if the user wants to redirect
646  * output to a file and/or syslog. If neither are provided, then we bounce
647  * everything back to parent's stdout.
648  */
649 static void
650 do_output(const unsigned char *buf, size_t len, struct daemon_state *state)
651 {
652 	assert(len <= LBUF_SIZE);
653 	assert(state != NULL);
654 
655 	if (len < 1) {
656 		return;
657 	}
658 	if (state->syslog_enabled) {
659 		syslog(state->syslog_priority, "%.*s", (int)len, buf);
660 	}
661 	if (state->output_fd != -1) {
662 		if (write(state->output_fd, buf, len) == -1)
663 			warn("write");
664 	}
665 	if (state->keep_fds_open &&
666 	    !state->syslog_enabled &&
667 	    state->output_fd == -1) {
668 		printf("%.*s", (int)len, buf);
669 	}
670 }
671 
672 /*
673  * We use the global PID acquired directly from fork. If there is no valid
674  * child pid, the handler should be blocked and/or child_gone == 1.
675  */
676 static void
677 handle_term(int signo)
678 {
679 	if (pid > 0 && !child_gone) {
680 		kill(pid, signo);
681 	}
682 	terminate = 1;
683 }
684 
685 static void
686 handle_chld(int signo __unused)
687 {
688 
689 	for (;;) {
690 		int rv = waitpid(-1, NULL, WNOHANG);
691 		if (pid == rv) {
692 			child_gone = 1;
693 			break;
694 		} else if (rv == -1 && errno != EINTR) {
695 			warn("waitpid");
696 			return;
697 		}
698 	}
699 }
700 
701 static void
702 handle_hup(int signo __unused)
703 {
704 
705 	do_log_reopen = 1;
706 }
707 
708 static int
709 open_log(const char *outfn)
710 {
711 
712 	return open(outfn, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0600);
713 }
714 
715 static void
716 reopen_log(struct daemon_state *state)
717 {
718 	int outfd;
719 
720 	do_log_reopen = 0;
721 	outfd = open_log(state->output_filename);
722 	if (state->output_fd >= 0) {
723 		close(state->output_fd);
724 	}
725 	state->output_fd = outfd;
726 }
727 
728 static void
729 daemon_state_init(struct daemon_state *state)
730 {
731 	*state = (struct daemon_state) {
732 		.pipe_fd = { -1, -1 },
733 		.parent_pidfh = NULL,
734 		.child_pidfh = NULL,
735 		.child_pidfile = NULL,
736 		.parent_pidfile = NULL,
737 		.title = NULL,
738 		.user = NULL,
739 		.supervision_enabled = false,
740 		.child_eof = false,
741 		.restart_enabled = false,
742 		.keep_cur_workdir = 1,
743 		.restart_delay = 1,
744 		.stdmask = STDOUT_FILENO | STDERR_FILENO,
745 		.syslog_enabled = false,
746 		.log_reopen = false,
747 		.syslog_priority = LOG_NOTICE,
748 		.syslog_tag = "daemon",
749 		.syslog_facility = LOG_DAEMON,
750 		.keep_fds_open = 1,
751 		.output_fd = -1,
752 		.output_filename = NULL,
753 	};
754 }
755 
756 static _Noreturn void
757 daemon_terminate(struct daemon_state *state)
758 {
759 	assert(state != NULL);
760 	close(state->output_fd);
761 	close(state->pipe_fd[0]);
762 	close(state->pipe_fd[1]);
763 	if (state->syslog_enabled) {
764 		closelog();
765 	}
766 	pidfile_remove(state->child_pidfh);
767 	pidfile_remove(state->parent_pidfh);
768 
769 	/*
770 	 * Note that the exit value here doesn't matter in the case of a clean
771 	 * exit; daemon(3) already detached us from the caller, nothing is left
772 	 * to care about this one.
773 	 */
774 	exit(1);
775 }
776