1 /* vi: set sw=4 ts=4: */
2 /*
3 * Mini start-stop-daemon implementation(s) for busybox
4 *
5 * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
6 * Adapted for busybox David Kimdon <dwhedon@gordian.com>
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 */
10
11 /*
12 This is how it is supposed to work:
13
14 start-stop-daemon [OPTIONS] [--start|--stop] [[--] arguments...]
15
16 One (only) of these must be given:
17 -S,--start Start
18 -K,--stop Stop
19
20 Search for matching processes.
21 If --stop is given, stop all matching processes (by sending a signal).
22 If --start is given, start a new process unless a matching process was found.
23
24 Options controlling process matching
25 (if multiple conditions are specified, all must match):
26 -u,--user USERNAME|UID Only consider this user's processes
27 -n,--name PROCESS_NAME Look for processes by matching PROCESS_NAME
28 with comm field in /proc/$PID/stat.
29 Only basename is compared:
30 "ntpd" == "./ntpd" == "/path/to/ntpd".
31 [TODO: can PROCESS_NAME be a full pathname? Should we require full match then
32 with /proc/$PID/exe or argv[0] (comm can't be matched, it never contains path)]
33 -x,--exec EXECUTABLE Look for processes that were started with this
34 command in /proc/$PID/exe and /proc/$PID/cmdline
35 (/proc/$PID/cmdline is a bbox extension)
36 Unlike -n, we match against the full path:
37 "ntpd" != "./ntpd" != "/path/to/ntpd"
38 -p,--pidfile PID_FILE Look for processes with PID from this file
39
40 Options which are valid for --start only:
41 -x,--exec EXECUTABLE Program to run (1st arg of execvp). Mandatory.
42 -a,--startas NAME argv[0] (defaults to EXECUTABLE)
43 -b,--background Put process into background
44 -N,--nicelevel N Add N to process' nice level
45 -c,--chuid USER[:[GRP]] Change to specified user [and group]
46 -m,--make-pidfile Write PID to the pidfile
47 (both -m and -p must be given!)
48
49 Options which are valid for --stop only:
50 -s,--signal SIG Signal to send (default:TERM)
51 -t,--test Exit with status 0 if process is found
52 (we don't actually start or stop daemons)
53
54 Misc options:
55 -o,--oknodo Exit with status 0 if nothing is done
56 -q,--quiet Quiet
57 -v,--verbose Verbose
58 */
59 //config:config START_STOP_DAEMON
60 //config: bool "start-stop-daemon (12 kb)"
61 //config: default y
62 //config: help
63 //config: start-stop-daemon is used to control the creation and
64 //config: termination of system-level processes, usually the ones
65 //config: started during the startup of the system.
66 //config:
67 //config:config FEATURE_START_STOP_DAEMON_LONG_OPTIONS
68 //config: bool "Enable long options"
69 //config: default y
70 //config: depends on START_STOP_DAEMON && LONG_OPTS
71 //config:
72 //config:config FEATURE_START_STOP_DAEMON_FANCY
73 //config: bool "Support additional arguments"
74 //config: default y
75 //config: depends on START_STOP_DAEMON
76 //config: help
77 //config: -o|--oknodo ignored since we exit with 0 anyway
78 //config: -v|--verbose
79 //config: -N|--nicelevel N
80
81 //applet:IF_START_STOP_DAEMON(APPLET_ODDNAME(start-stop-daemon, start_stop_daemon, BB_DIR_SBIN, BB_SUID_DROP, start_stop_daemon))
82 /* not NOEXEC: uses bb_common_bufsiz1 */
83
84 //kbuild:lib-$(CONFIG_START_STOP_DAEMON) += start_stop_daemon.o
85
86 //usage:#define start_stop_daemon_trivial_usage
87 //usage: "[OPTIONS] [-S|-K] ... [-- ARGS...]"
88 //usage:#define start_stop_daemon_full_usage "\n\n"
89 //usage: "Search for matching processes, and then\n"
90 //usage: "-K: stop all matching processes\n"
91 //usage: "-S: start a process unless a matching process is found\n"
92 //usage: "\nProcess matching:"
93 //usage: "\n -u USERNAME|UID Match only this user's processes"
94 //usage: "\n -n NAME Match processes with NAME"
95 //usage: "\n in comm field in /proc/PID/stat"
96 //usage: "\n -x EXECUTABLE Match processes with this command"
97 //usage: "\n in /proc/PID/cmdline"
98 //usage: "\n -p FILE Match a process with PID from FILE"
99 //usage: "\n All specified conditions must match"
100 //usage: "\n-S only:"
101 //usage: "\n -x EXECUTABLE Program to run"
102 //usage: "\n -a NAME Zeroth argument"
103 //usage: "\n -b Background"
104 //usage: IF_FEATURE_START_STOP_DAEMON_FANCY(
105 //usage: "\n -N N Change nice level"
106 //usage: )
107 //usage: "\n -c USER[:[GRP]] Change user/group"
108 //usage: "\n -m Write PID to pidfile specified by -p"
109 //usage: "\n-K only:"
110 //usage: "\n -s SIG Signal to send"
111 //usage: "\n -t Match only, exit with 0 if found"
112 //usage: "\nOther:"
113 //usage: IF_FEATURE_START_STOP_DAEMON_FANCY(
114 //usage: "\n -o Exit with status 0 if nothing is done"
115 //usage: "\n -v Verbose"
116 //usage: )
117 //usage: "\n -q Quiet"
118
119 /* Override ENABLE_FEATURE_PIDFILE */
120 #define WANT_PIDFILE 1
121 #include "libbb.h"
122 #include "common_bufsiz.h"
123
124 struct pid_list {
125 struct pid_list *next;
126 pid_t pid;
127 };
128
129 enum {
130 CTX_STOP = (1 << 0),
131 CTX_START = (1 << 1),
132 OPT_BACKGROUND = (1 << 2), // -b
133 OPT_QUIET = (1 << 3), // -q
134 OPT_TEST = (1 << 4), // -t
135 OPT_MAKEPID = (1 << 5), // -m
136 OPT_a = (1 << 6), // -a
137 OPT_n = (1 << 7), // -n
138 OPT_s = (1 << 8), // -s
139 OPT_u = (1 << 9), // -u
140 OPT_c = (1 << 10), // -c
141 OPT_x = (1 << 11), // -x
142 OPT_p = (1 << 12), // -p
143 OPT_OKNODO = (1 << 13) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
144 OPT_VERBOSE = (1 << 14) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
145 OPT_NICELEVEL = (1 << 15) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
146 };
147 #define QUIET (option_mask32 & OPT_QUIET)
148 #define TEST (option_mask32 & OPT_TEST)
149
150 struct globals {
151 struct pid_list *found_procs;
152 char *userspec;
153 char *cmdname;
154 char *execname;
155 char *pidfile;
156 char *execname_cmpbuf;
157 unsigned execname_sizeof;
158 int user_id;
159 smallint signal_nr;
160 #ifdef OLDER_VERSION_OF_X
161 struct stat execstat;
162 #endif
163 } FIX_ALIASING;
164 #define G (*(struct globals*)bb_common_bufsiz1)
165 #define userspec (G.userspec )
166 #define cmdname (G.cmdname )
167 #define execname (G.execname )
168 #define pidfile (G.pidfile )
169 #define user_id (G.user_id )
170 #define signal_nr (G.signal_nr )
171 #define INIT_G() do { \
172 setup_common_bufsiz(); \
173 user_id = -1; \
174 signal_nr = 15; \
175 } while (0)
176
177 #ifdef OLDER_VERSION_OF_X
178 /* -x,--exec EXECUTABLE
179 * Look for processes with matching /proc/$PID/exe.
180 * Match is performed using device+inode.
181 */
pid_is_exec(pid_t pid)182 static int pid_is_exec(pid_t pid)
183 {
184 struct stat st;
185 char buf[sizeof("/proc/%u/exe") + sizeof(int)*3];
186
187 sprintf(buf, "/proc/%u/exe", (unsigned)pid);
188 if (stat(buf, &st) < 0)
189 return 0;
190 if (st.st_dev == G.execstat.st_dev
191 && st.st_ino == G.execstat.st_ino)
192 return 1;
193 return 0;
194 }
195 #else
pid_is_exec(pid_t pid)196 static int pid_is_exec(pid_t pid)
197 {
198 ssize_t bytes;
199 char buf[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
200 char *procname, *exelink;
201 int match;
202
203 procname = buf + sprintf(buf, "/proc/%u/exe", (unsigned)pid) - 3;
204
205 exelink = xmalloc_readlink(buf);
206 match = (exelink && strcmp(execname, exelink) == 0);
207 free(exelink);
208 if (match)
209 return match;
210
211 strcpy(procname, "cmdline");
212 bytes = open_read_close(buf, G.execname_cmpbuf, G.execname_sizeof);
213 if (bytes > 0) {
214 G.execname_cmpbuf[bytes] = '\0';
215 return strcmp(execname, G.execname_cmpbuf) == 0;
216 }
217 return 0;
218 }
219 #endif
220
pid_is_name(pid_t pid)221 static int pid_is_name(pid_t pid)
222 {
223 /* /proc/PID/stat is "PID (comm_15_bytes_max) ..." */
224 char buf[32]; /* should be enough */
225 char *p, *pe;
226
227 sprintf(buf, "/proc/%u/stat", (unsigned)pid);
228 if (open_read_close(buf, buf, sizeof(buf) - 1) < 0)
229 return 0;
230 buf[sizeof(buf) - 1] = '\0'; /* paranoia */
231 p = strchr(buf, '(');
232 if (!p)
233 return 0;
234 pe = strrchr(++p, ')');
235 if (!pe)
236 return 0;
237 *pe = '\0';
238 /* we require comm to match and to not be truncated */
239 /* in Linux, if comm is 15 chars, it may be a truncated
240 * name, so we don't allow that to match */
241 if (strlen(p) >= COMM_LEN - 1) /* COMM_LEN is 16 */
242 return 0;
243 return strcmp(p, cmdname) == 0;
244 }
245
pid_is_user(int pid)246 static int pid_is_user(int pid)
247 {
248 struct stat sb;
249 char buf[sizeof("/proc/") + sizeof(int)*3];
250
251 sprintf(buf, "/proc/%u", (unsigned)pid);
252 if (stat(buf, &sb) != 0)
253 return 0;
254 return (sb.st_uid == (uid_t)user_id);
255 }
256
check(int pid)257 static void check(int pid)
258 {
259 struct pid_list *p;
260
261 if (execname && !pid_is_exec(pid)) {
262 return;
263 }
264 if (cmdname && !pid_is_name(pid)) {
265 return;
266 }
267 if (userspec && !pid_is_user(pid)) {
268 return;
269 }
270 p = xmalloc(sizeof(*p));
271 p->next = G.found_procs;
272 p->pid = pid;
273 G.found_procs = p;
274 }
275
do_pidfile(void)276 static void do_pidfile(void)
277 {
278 FILE *f;
279 unsigned pid;
280
281 f = fopen_for_read(pidfile);
282 if (f) {
283 if (fscanf(f, "%u", &pid) == 1)
284 check(pid);
285 fclose(f);
286 } else if (errno != ENOENT)
287 bb_perror_msg_and_die("open pidfile %s", pidfile);
288 }
289
do_procinit(void)290 static void do_procinit(void)
291 {
292 DIR *procdir;
293 struct dirent *entry;
294 int pid;
295
296 if (pidfile) {
297 do_pidfile();
298 return;
299 }
300
301 procdir = xopendir("/proc");
302
303 pid = 0;
304 while (1) {
305 errno = 0; /* clear any previous error */
306 entry = readdir(procdir);
307 // TODO: this check is too generic, it's better
308 // to check for exact errno(s) which mean that we got stale entry
309 if (errno) /* Stale entry, process has died after opendir */
310 continue;
311 if (!entry) /* EOF, no more entries */
312 break;
313 pid = bb_strtou(entry->d_name, NULL, 10);
314 if (errno) /* NaN */
315 continue;
316 check(pid);
317 }
318 closedir(procdir);
319 if (!pid)
320 bb_simple_error_msg_and_die("nothing in /proc - not mounted?");
321 }
322
do_stop(void)323 static int do_stop(void)
324 {
325 char *what;
326 struct pid_list *p;
327 int killed = 0;
328
329 if (cmdname) {
330 if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(cmdname);
331 if (!ENABLE_FEATURE_CLEAN_UP) what = cmdname;
332 } else if (execname) {
333 if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
334 if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
335 } else if (pidfile) {
336 what = xasprintf("process in pidfile '%s'", pidfile);
337 } else if (userspec) {
338 what = xasprintf("process(es) owned by '%s'", userspec);
339 } else {
340 bb_simple_error_msg_and_die("internal error, please report");
341 }
342
343 if (!G.found_procs) {
344 if (!QUIET)
345 printf("no %s found; none killed\n", what);
346 killed = -1;
347 goto ret;
348 }
349 for (p = G.found_procs; p; p = p->next) {
350 if (kill(p->pid, TEST ? 0 : signal_nr) == 0) {
351 killed++;
352 } else {
353 bb_perror_msg("warning: killing process %u", (unsigned)p->pid);
354 p->pid = 0;
355 if (TEST) {
356 /* Example: -K --test --pidfile PIDFILE detected
357 * that PIDFILE's pid doesn't exist */
358 killed = -1;
359 goto ret;
360 }
361 }
362 }
363 if (!QUIET && killed) {
364 printf("stopped %s (pid", what);
365 for (p = G.found_procs; p; p = p->next)
366 if (p->pid)
367 printf(" %u", (unsigned)p->pid);
368 puts(")");
369 }
370 ret:
371 if (ENABLE_FEATURE_CLEAN_UP)
372 free(what);
373 return killed;
374 }
375
376 #if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
377 static const char start_stop_daemon_longopts[] ALIGN1 =
378 "stop\0" No_argument "K"
379 "start\0" No_argument "S"
380 "background\0" No_argument "b"
381 "quiet\0" No_argument "q"
382 "test\0" No_argument "t"
383 "make-pidfile\0" No_argument "m"
384 # if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
385 "oknodo\0" No_argument "o"
386 "verbose\0" No_argument "v"
387 "nicelevel\0" Required_argument "N"
388 # endif
389 "startas\0" Required_argument "a"
390 "name\0" Required_argument "n"
391 "signal\0" Required_argument "s"
392 "user\0" Required_argument "u"
393 "chuid\0" Required_argument "c"
394 "exec\0" Required_argument "x"
395 "pidfile\0" Required_argument "p"
396 # if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
397 "retry\0" Required_argument "R"
398 # endif
399 ;
400 # define GETOPT32 getopt32long
401 # define LONGOPTS start_stop_daemon_longopts,
402 #else
403 # define GETOPT32 getopt32
404 # define LONGOPTS
405 #endif
406
407 int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
start_stop_daemon_main(int argc UNUSED_PARAM,char ** argv)408 int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
409 {
410 unsigned opt;
411 char *signame;
412 char *startas = NULL;
413 char *chuid;
414 #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
415 // char *retry_arg = NULL;
416 // int retries = -1;
417 char *opt_N;
418 #endif
419
420 INIT_G();
421
422 opt = GETOPT32(argv, "^"
423 "KSbqtma:n:s:u:c:x:p:"
424 IF_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:")
425 /* -K or -S is required; they are mutually exclusive */
426 /* -p is required if -m is given */
427 /* -xpun (at least one) is required if -K is given */
428 // /* -xa (at least one) is required if -S is given */
429 //WRONG: "start-stop-daemon -S -- sleep 5" is a valid invocation
430 /* -q turns off -v */
431 "\0"
432 "K:S:K--S:S--K:m?p:K?xpun"
433 IF_FEATURE_START_STOP_DAEMON_FANCY("q-v"),
434 LONGOPTS
435 &startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
436 IF_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
437 /* We accept and ignore -R <param> / --retry <param> */
438 IF_FEATURE_START_STOP_DAEMON_FANCY(,NULL)
439 );
440
441 if (opt & OPT_s) {
442 signal_nr = get_signum(signame);
443 if (signal_nr < 0) bb_show_usage();
444 }
445
446 //argc -= optind;
447 argv += optind;
448 // ARGS contains zeroth arg if -x/-a is not given, else it starts with 1st arg.
449 // These will try to execute "[/bin/]sleep 5":
450 // "start-stop-daemon -S -- sleep 5"
451 // "start-stop-daemon -S -x /bin/sleep -- 5"
452 // "start-stop-daemon -S -a sleep -- 5"
453 // NB: -n option does _not_ behave in this way: this will try to execute "5":
454 // "start-stop-daemon -S -n sleep -- 5"
455 if (opt & CTX_START) {
456 if (!execname) { /* -x is not given */
457 execname = startas;
458 if (!execname) { /* neither -x nor -a is given */
459 execname = argv[0];
460 if (!execname)
461 bb_show_usage();
462 argv++;
463 }
464 }
465 if (!startas) /* -a is not given: use -x EXECUTABLE or argv[0] */
466 startas = execname;
467 *--argv = startas;
468 }
469 if (execname) {
470 G.execname_sizeof = strlen(execname) + 1;
471 G.execname_cmpbuf = xmalloc(G.execname_sizeof + 1);
472 }
473 // IF_FEATURE_START_STOP_DAEMON_FANCY(
474 // if (retry_arg)
475 // retries = xatoi_positive(retry_arg);
476 // )
477 if (userspec) {
478 user_id = bb_strtou(userspec, NULL, 10);
479 if (errno)
480 user_id = xuname2uid(userspec);
481 }
482
483 /* Both start and stop need to know current processes */
484 do_procinit();
485
486 if (opt & CTX_STOP) {
487 int i = do_stop();
488 return (opt & OPT_OKNODO) ? 0 : (i <= 0);
489 }
490
491 /* else: CTX_START (-S). execname can't be NULL. */
492
493 if (G.found_procs) {
494 if (!QUIET)
495 printf("%s is already running\n", execname);
496 return !(opt & OPT_OKNODO);
497 }
498
499 #ifdef OLDER_VERSION_OF_X
500 if (execname)
501 xstat(execname, &G.execstat);
502 #endif
503
504 if (opt & OPT_BACKGROUND) {
505 /* Daemons usually call bb_daemonize_or_rexec(), but SSD can do
506 * without: SSD is not itself a daemon, it _execs_ a daemon.
507 * The usual NOMMU problem of "child can't run indefinitely,
508 * it must exec" does not bite us: we exec anyway.
509 *
510 * bb_daemonize(DAEMON_DEVNULL_STDIO | DAEMON_CLOSE_EXTRA_FDS | DAEMON_DOUBLE_FORK)
511 * can be used on MMU systems, but use of vfork()
512 * is preferable since we want to create pidfile
513 * _before_ parent returns, and vfork() on Linux
514 * ensures that (by blocking parent until exec in the child).
515 */
516 pid_t pid = xvfork();
517 if (pid != 0) {
518 /* Parent */
519 /* why _exit? the child may have changed the stack,
520 * so "return 0" may do bad things
521 */
522 _exit(EXIT_SUCCESS);
523 }
524 /* Child */
525 setsid(); /* detach from controlling tty */
526 /* Redirect stdio to /dev/null, close extra FDs */
527 bb_daemon_helper(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS);
528 /* On Linux, session leader can acquire ctty
529 * unknowingly, by opening a tty.
530 * Prevent this: stop being a session leader.
531 */
532 pid = xvfork();
533 if (pid != 0)
534 _exit(EXIT_SUCCESS); /* Parent */
535 }
536 if (opt & OPT_MAKEPID) {
537 /* User wants _us_ to make the pidfile */
538 write_pidfile(pidfile);
539 }
540 #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
541 if (opt & OPT_NICELEVEL) {
542 /* Set process priority (must be before OPT_c) */
543 int prio = getpriority(PRIO_PROCESS, 0) + xatoi_range(opt_N, INT_MIN/2, INT_MAX/2);
544 if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
545 bb_perror_msg_and_die("setpriority(%d)", prio);
546 }
547 }
548 #endif
549 if (opt & OPT_c) {
550 struct bb_uidgid_t ugid;
551 parse_chown_usergroup_or_die(&ugid, chuid);
552 if (ugid.uid != (uid_t) -1L) {
553 struct passwd *pw = xgetpwuid(ugid.uid);
554 if (ugid.gid != (gid_t) -1L)
555 pw->pw_gid = ugid.gid;
556 /* initgroups, setgid, setuid: */
557 change_identity(pw);
558 } else if (ugid.gid != (gid_t) -1L) {
559 xsetgid(ugid.gid);
560 setgroups(1, &ugid.gid);
561 }
562 }
563 /* Try:
564 * strace -oLOG start-stop-daemon -S -x /bin/usleep -a qwerty 500000
565 * should exec "/bin/usleep", but argv[0] should be "qwerty":
566 */
567 execvp(execname, argv);
568 bb_perror_msg_and_die("can't execute '%s'", startas);
569 }
570