aboutsummaryrefslogtreecommitdiff
path: root/debianutils/start_stop_daemon.c
blob: 4a9e0653e29a8da9a5a9c519fccab74e654490ae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
/* vi: set sw=4 ts=4: */
/*
 * Mini start-stop-daemon implementation(s) for busybox
 *
 * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
 * Adapted for busybox David Kimdon <dwhedon@gordian.com>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

/*
This is how it is supposed to work:

start-stop-daemon [OPTIONS] [--start|--stop] [[--] arguments...]

One (only) of these must be given:
        -S,--start              Start
        -K,--stop               Stop

Search for matching processes.
If --stop is given, stop all matching processes (by sending a signal).
If --start is given, start a new process unless a matching process was found.

Options controlling process matching
(if multiple conditions are specified, all must match):
        -u,--user USERNAME|UID  Only consider this user's processes
        -n,--name PROCESS_NAME  Look for processes by matching PROCESS_NAME
                                with comm field in /proc/$PID/stat.
                                Only basename is compared:
                                "ntpd" == "./ntpd" == "/path/to/ntpd".
[TODO: can PROCESS_NAME be a full pathname? Should we require full match then
with /proc/$PID/exe or argv[0] (comm can't be matched, it never contains path)]
        -x,--exec EXECUTABLE    Look for processes that were started with this
                                command in /proc/$PID/exe and /proc/$PID/cmdline
                                (/proc/$PID/cmdline is a bbox extension)
                                Unlike -n, we match against the full path:
                                "ntpd" != "./ntpd" != "/path/to/ntpd"
        -p,--pidfile PID_FILE   Look for processes with PID from this file

Options which are valid for --start only:
        -x,--exec EXECUTABLE    Program to run (1st arg of execvp). Mandatory.
        -a,--startas NAME       argv[0] (defaults to EXECUTABLE)
        -b,--background         Put process into background
        -N,--nicelevel N        Add N to process' nice level
        -c,--chuid USER[:[GRP]] Change to specified user [and group]
        -m,--make-pidfile       Write PID to the pidfile
                                (both -m and -p must be given!)

Options which are valid for --stop only:
        -s,--signal SIG         Signal to send (default:TERM)
        -t,--test               Exit with status 0 if process is found
                                (we don't actually start or stop daemons)

Misc options:
        -o,--oknodo             Exit with status 0 if nothing is done
        -q,--quiet              Quiet
        -v,--verbose            Verbose
*/
//config:config START_STOP_DAEMON
//config:	bool "start-stop-daemon"
//config:	default y
//config:	help
//config:	  start-stop-daemon is used to control the creation and
//config:	  termination of system-level processes, usually the ones
//config:	  started during the startup of the system.
//config:
//config:config FEATURE_START_STOP_DAEMON_LONG_OPTIONS
//config:	bool "Enable long options"
//config:	default y
//config:	depends on START_STOP_DAEMON && LONG_OPTS
//config:
//config:config FEATURE_START_STOP_DAEMON_FANCY
//config:	bool "Support additional arguments"
//config:	default y
//config:	depends on START_STOP_DAEMON
//config:	help
//config:	  -o|--oknodo ignored since we exit with 0 anyway
//config:	  -v|--verbose
//config:	  -N|--nicelevel N

//applet:IF_START_STOP_DAEMON(APPLET_ODDNAME(start-stop-daemon, start_stop_daemon, BB_DIR_SBIN, BB_SUID_DROP, start_stop_daemon))

//kbuild:lib-$(CONFIG_START_STOP_DAEMON) += start_stop_daemon.o

//usage:#define start_stop_daemon_trivial_usage
//usage:       "[OPTIONS] [-S|-K] ... [-- ARGS...]"
//usage:#define start_stop_daemon_full_usage "\n\n"
//usage:       "Search for matching processes, and then\n"
//usage:       "-K: stop all matching processes.\n"
//usage:       "-S: start a process unless a matching process is found.\n"
//usage:	IF_FEATURE_START_STOP_DAEMON_LONG_OPTIONS(
//usage:     "\nProcess matching:"
//usage:     "\n	-u,--user USERNAME|UID	Match only this user's processes"
//usage:     "\n	-n,--name NAME		Match processes with NAME"
//usage:     "\n				in comm field in /proc/PID/stat"
//usage:     "\n	-x,--exec EXECUTABLE	Match processes with this command"
//usage:     "\n				in /proc/PID/{exe,cmdline}"
//usage:     "\n	-p,--pidfile FILE	Match a process with PID from the file"
//usage:     "\n	All specified conditions must match"
//usage:     "\n-S only:"
//usage:     "\n	-x,--exec EXECUTABLE	Program to run"
//usage:     "\n	-a,--startas NAME	Zeroth argument"
//usage:     "\n	-b,--background		Background"
//usage:	IF_FEATURE_START_STOP_DAEMON_FANCY(
//usage:     "\n	-N,--nicelevel N	Change nice level"
//usage:	)
//usage:     "\n	-c,--chuid USER[:[GRP]]	Change to user/group"
//usage:     "\n	-m,--make-pidfile	Write PID to the pidfile specified by -p"
//usage:     "\n-K only:"
//usage:     "\n	-s,--signal SIG		Signal to send"
//usage:     "\n	-t,--test		Match only, exit with 0 if a process is found"
//usage:     "\nOther:"
//usage:	IF_FEATURE_START_STOP_DAEMON_FANCY(
//usage:     "\n	-o,--oknodo		Exit with status 0 if nothing is done"
//usage:     "\n	-v,--verbose		Verbose"
//usage:	)
//usage:     "\n	-q,--quiet		Quiet"
//usage:	)
//usage:	IF_NOT_FEATURE_START_STOP_DAEMON_LONG_OPTIONS(
//usage:     "\nProcess matching:"
//usage:     "\n	-u USERNAME|UID	Match only this user's processes"
//usage:     "\n	-n NAME		Match processes with NAME"
//usage:     "\n			in comm field in /proc/PID/stat"
//usage:     "\n	-x EXECUTABLE	Match processes with this command"
//usage:     "\n			command in /proc/PID/cmdline"
//usage:     "\n	-p FILE		Match a process with PID from the file"
//usage:     "\n	All specified conditions must match"
//usage:     "\n-S only:"
//usage:     "\n	-x EXECUTABLE	Program to run"
//usage:     "\n	-a NAME		Zeroth argument"
//usage:     "\n	-b		Background"
//usage:	IF_FEATURE_START_STOP_DAEMON_FANCY(
//usage:     "\n	-N N		Change nice level"
//usage:	)
//usage:     "\n	-c USER[:[GRP]]	Change to user/group"
//usage:     "\n	-m		Write PID to the pidfile specified by -p"
//usage:     "\n-K only:"
//usage:     "\n	-s SIG		Signal to send"
//usage:     "\n	-t		Match only, exit with 0 if a process is found"
//usage:     "\nOther:"
//usage:	IF_FEATURE_START_STOP_DAEMON_FANCY(
//usage:     "\n	-o		Exit with status 0 if nothing is done"
//usage:     "\n	-v		Verbose"
//usage:	)
//usage:     "\n	-q		Quiet"
//usage:	)

#include <sys/resource.h>

/* Override ENABLE_FEATURE_PIDFILE */
#define WANT_PIDFILE 1
#include "libbb.h"
#include "common_bufsiz.h"

struct pid_list {
	struct pid_list *next;
	pid_t pid;
};

enum {
	CTX_STOP       = (1 <<  0),
	CTX_START      = (1 <<  1),
	OPT_BACKGROUND = (1 <<  2), // -b
	OPT_QUIET      = (1 <<  3), // -q
	OPT_TEST       = (1 <<  4), // -t
	OPT_MAKEPID    = (1 <<  5), // -m
	OPT_a          = (1 <<  6), // -a
	OPT_n          = (1 <<  7), // -n
	OPT_s          = (1 <<  8), // -s
	OPT_u          = (1 <<  9), // -u
	OPT_c          = (1 << 10), // -c
	OPT_x          = (1 << 11), // -x
	OPT_p          = (1 << 12), // -p
	OPT_OKNODO     = (1 << 13) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
	OPT_VERBOSE    = (1 << 14) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
	OPT_NICELEVEL  = (1 << 15) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
};
#define QUIET (option_mask32 & OPT_QUIET)
#define TEST  (option_mask32 & OPT_TEST)

struct globals {
	struct pid_list *found_procs;
	char *userspec;
	char *cmdname;
	char *execname;
	char *pidfile;
	char *execname_cmpbuf;
	unsigned execname_sizeof;
	int user_id;
	smallint signal_nr;
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define userspec          (G.userspec            )
#define cmdname           (G.cmdname             )
#define execname          (G.execname            )
#define pidfile           (G.pidfile             )
#define user_id           (G.user_id             )
#define signal_nr         (G.signal_nr           )
#define INIT_G() do { \
	setup_common_bufsiz(); \
	user_id = -1; \
	signal_nr = 15; \
} while (0)

#ifdef OLDER_VERSION_OF_X
/* -x,--exec EXECUTABLE
 * Look for processes with matching /proc/$PID/exe.
 * Match is performed using device+inode.
 */
static int pid_is_exec(pid_t pid)
{
	struct stat st;
	char buf[sizeof("/proc/%u/exe") + sizeof(int)*3];

	sprintf(buf, "/proc/%u/exe", (unsigned)pid);
	if (stat(buf, &st) < 0)
		return 0;
	if (st.st_dev == execstat.st_dev
	 && st.st_ino == execstat.st_ino)
		return 1;
	return 0;
}
#endif

static int pid_is_exec(pid_t pid)
{
	ssize_t bytes;
	char buf[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
	char *procname, *exelink;
	int match;

	procname = buf + sprintf(buf, "/proc/%u/exe", (unsigned)pid) - 3;

	exelink = xmalloc_readlink(buf);
	match = (exelink && strcmp(execname, exelink) == 0);
	free(exelink);
	if (match)
		return match;

	strcpy(procname, "cmdline");
	bytes = open_read_close(buf, G.execname_cmpbuf, G.execname_sizeof);
	if (bytes > 0) {
		G.execname_cmpbuf[bytes] = '\0';
		return strcmp(execname, G.execname_cmpbuf) == 0;
	}
	return 0;
}

static int pid_is_name(pid_t pid)
{
	/* /proc/PID/stat is "PID (comm_15_bytes_max) ..." */
	char buf[32]; /* should be enough */
	char *p, *pe;

	sprintf(buf, "/proc/%u/stat", (unsigned)pid);
	if (open_read_close(buf, buf, sizeof(buf) - 1) < 0)
		return 0;
	buf[sizeof(buf) - 1] = '\0'; /* paranoia */
	p = strchr(buf, '(');
	if (!p)
		return 0;
	pe = strrchr(++p, ')');
	if (!pe)
		return 0;
	*pe = '\0';
	/* we require comm to match and to not be truncated */
	/* in Linux, if comm is 15 chars, it may be a truncated
	 * name, so we don't allow that to match */
	if (strlen(p) >= COMM_LEN - 1) /* COMM_LEN is 16 */
		return 0;
	return strcmp(p, cmdname) == 0;
}

static int pid_is_user(int pid)
{
	struct stat sb;
	char buf[sizeof("/proc/") + sizeof(int)*3];

	sprintf(buf, "/proc/%u", (unsigned)pid);
	if (stat(buf, &sb) != 0)
		return 0;
	return (sb.st_uid == (uid_t)user_id);
}

static void check(int pid)
{
	struct pid_list *p;

	if (execname && !pid_is_exec(pid)) {
		return;
	}
	if (cmdname && !pid_is_name(pid)) {
		return;
	}
	if (userspec && !pid_is_user(pid)) {
		return;
	}
	p = xmalloc(sizeof(*p));
	p->next = G.found_procs;
	p->pid = pid;
	G.found_procs = p;
}

static void do_pidfile(void)
{
	FILE *f;
	unsigned pid;

	f = fopen_for_read(pidfile);
	if (f) {
		if (fscanf(f, "%u", &pid) == 1)
			check(pid);
		fclose(f);
	} else if (errno != ENOENT)
		bb_perror_msg_and_die("open pidfile %s", pidfile);
}

static void do_procinit(void)
{
	DIR *procdir;
	struct dirent *entry;
	int pid;

	if (pidfile) {
		do_pidfile();
		return;
	}

	procdir = xopendir("/proc");

	pid = 0;
	while (1) {
		errno = 0; /* clear any previous error */
		entry = readdir(procdir);
// TODO: this check is too generic, it's better
// to check for exact errno(s) which mean that we got stale entry
		if (errno) /* Stale entry, process has died after opendir */
			continue;
		if (!entry) /* EOF, no more entries */
			break;
		pid = bb_strtou(entry->d_name, NULL, 10);
		if (errno) /* NaN */
			continue;
		check(pid);
	}
	closedir(procdir);
	if (!pid)
		bb_error_msg_and_die("nothing in /proc - not mounted?");
}

static int do_stop(void)
{
	char *what;
	struct pid_list *p;
	int killed = 0;

	if (cmdname) {
		if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(cmdname);
		if (!ENABLE_FEATURE_CLEAN_UP) what = cmdname;
	} else if (execname) {
		if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
		if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
	} else if (pidfile) {
		what = xasprintf("process in pidfile '%s'", pidfile);
	} else if (userspec) {
		what = xasprintf("process(es) owned by '%s'", userspec);
	} else {
		bb_error_msg_and_die("internal error, please report");
	}

	if (!G.found_procs) {
		if (!QUIET)
			printf("no %s found; none killed\n", what);
		killed = -1;
		goto ret;
	}
	for (p = G.found_procs; p; p = p->next) {
		if (kill(p->pid, TEST ? 0 : signal_nr) == 0) {
			killed++;
		} else {
			bb_perror_msg("warning: killing process %u", (unsigned)p->pid);
			p->pid = 0;
			if (TEST) {
				/* Example: -K --test --pidfile PIDFILE detected
				 * that PIDFILE's pid doesn't exist */
				killed = -1;
				goto ret;
			}
		}
	}
	if (!QUIET && killed) {
		printf("stopped %s (pid", what);
		for (p = G.found_procs; p; p = p->next)
			if (p->pid)
				printf(" %u", (unsigned)p->pid);
		puts(")");
	}
 ret:
	if (ENABLE_FEATURE_CLEAN_UP)
		free(what);
	return killed;
}

#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
static const char start_stop_daemon_longopts[] ALIGN1 =
	"stop\0"         No_argument       "K"
	"start\0"        No_argument       "S"
	"background\0"   No_argument       "b"
	"quiet\0"        No_argument       "q"
	"test\0"         No_argument       "t"
	"make-pidfile\0" No_argument       "m"
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
	"oknodo\0"       No_argument       "o"
	"verbose\0"      No_argument       "v"
	"nicelevel\0"    Required_argument "N"
#endif
	"startas\0"      Required_argument "a"
	"name\0"         Required_argument "n"
	"signal\0"       Required_argument "s"
	"user\0"         Required_argument "u"
	"chuid\0"        Required_argument "c"
	"exec\0"         Required_argument "x"
	"pidfile\0"      Required_argument "p"
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
	"retry\0"        Required_argument "R"
#endif
	;
#endif

int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
{
	unsigned opt;
	char *signame;
	char *startas;
	char *chuid;
#ifdef OLDER_VERSION_OF_X
	struct stat execstat;
#endif
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
//	char *retry_arg = NULL;
//	int retries = -1;
	char *opt_N;
#endif

	INIT_G();

#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
	applet_long_options = start_stop_daemon_longopts;
#endif

	/* -K or -S is required; they are mutually exclusive */
	/* -p is required if -m is given */
	/* -xpun (at least one) is required if -K is given */
	/* -xa (at least one) is required if -S is given */
	/* -q turns off -v */
	opt_complementary = "K:S:K--S:S--K:m?p:K?xpun:S?xa"
		IF_FEATURE_START_STOP_DAEMON_FANCY("q-v");
	opt = getopt32(argv, "KSbqtma:n:s:u:c:x:p:"
		IF_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
		&startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
		IF_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
		/* We accept and ignore -R <param> / --retry <param> */
		IF_FEATURE_START_STOP_DAEMON_FANCY(,NULL)
	);

	if (opt & OPT_s) {
		signal_nr = get_signum(signame);
		if (signal_nr < 0) bb_show_usage();
	}

	if (!(opt & OPT_a))
		startas = execname;
	if (!execname) /* in case -a is given and -x is not */
		execname = startas;
	if (execname) {
		G.execname_sizeof = strlen(execname) + 1;
		G.execname_cmpbuf = xmalloc(G.execname_sizeof + 1);
	}

//	IF_FEATURE_START_STOP_DAEMON_FANCY(
//		if (retry_arg)
//			retries = xatoi_positive(retry_arg);
//	)
	//argc -= optind;
	argv += optind;

	if (userspec) {
		user_id = bb_strtou(userspec, NULL, 10);
		if (errno)
			user_id = xuname2uid(userspec);
	}
	/* Both start and stop need to know current processes */
	do_procinit();

	if (opt & CTX_STOP) {
		int i = do_stop();
		return (opt & OPT_OKNODO) ? 0 : (i <= 0);
	}

	if (G.found_procs) {
		if (!QUIET)
			printf("%s is already running\n%u\n", execname, (unsigned)G.found_procs->pid);
		return !(opt & OPT_OKNODO);
	}

#ifdef OLDER_VERSION_OF_X
	if (execname)
		xstat(execname, &execstat);
#endif

	*--argv = startas;
	if (opt & OPT_BACKGROUND) {
#if BB_MMU
		bb_daemonize(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS + DAEMON_DOUBLE_FORK);
		/* DAEMON_DEVNULL_STDIO is superfluous -
		 * it's always done by bb_daemonize() */
#else
		pid_t pid = xvfork();
		if (pid != 0) {
			/* parent */
			/* why _exit? the child may have changed the stack,
			 * so "return 0" may do bad things */
			_exit(EXIT_SUCCESS);
		}
		/* Child */
		setsid(); /* detach from controlling tty */
		/* Redirect stdio to /dev/null, close extra FDs.
		 * We do not actually daemonize because of DAEMON_ONLY_SANITIZE */
		bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO
			+ DAEMON_CLOSE_EXTRA_FDS
			+ DAEMON_ONLY_SANITIZE,
			NULL /* argv, unused */ );
#endif
	}
	if (opt & OPT_MAKEPID) {
		/* User wants _us_ to make the pidfile */
		write_pidfile(pidfile);
	}
	if (opt & OPT_c) {
		struct bb_uidgid_t ugid;
		parse_chown_usergroup_or_die(&ugid, chuid);
		if (ugid.uid != (uid_t) -1L) {
			struct passwd *pw = xgetpwuid(ugid.uid);
			if (ugid.gid != (gid_t) -1L)
				pw->pw_gid = ugid.gid;
			/* initgroups, setgid, setuid: */
			change_identity(pw);
		} else if (ugid.gid != (gid_t) -1L) {
			xsetgid(ugid.gid);
			setgroups(1, &ugid.gid);
		}
	}
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
	if (opt & OPT_NICELEVEL) {
		/* Set process priority */
		int prio = getpriority(PRIO_PROCESS, 0) + xatoi_range(opt_N, INT_MIN/2, INT_MAX/2);
		if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
			bb_perror_msg_and_die("setpriority(%d)", prio);
		}
	}
#endif
	execvp(startas, argv);
	bb_perror_msg_and_die("can't execute '%s'", startas);
}