summaryrefslogtreecommitdiff
path: root/debianutils/start_stop_daemon.c
blob: a2679f33112d39d20ae0541509ff45821014d7ed (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
/* 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 tarball for details.
 */

/* NB: we have a problem here with /proc/NN/exe usage, similar to
 * one fixed in killall/pidof */

#include <sys/resource.h>

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

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


struct globals {
	struct pid_list *found;
	char *userspec;
	char *cmdname;
	char *execname;
	char *pidfile;
	int user_id;
	smallint quiet;
	smallint signal_nr;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define found             (G.found               )
#define userspec          (G.userspec            )
#define cmdname           (G.cmdname             )
#define execname          (G.execname            )
#define pidfile           (G.pidfile             )
#define user_id           (G.user_id             )
#define quiet             (G.quiet               )
#define signal_nr         (G.signal_nr           )
#define INIT_G() \
        do { \
		user_id = -1; \
		signal_nr = 15; \
        } while (0)


static int pid_is_exec(pid_t pid, const char *name)
{
	char buf[sizeof("/proc//exe") + sizeof(int)*3];
	char *execbuf;
	int n;

	sprintf(buf, "/proc/%u/exe", pid);
	n = strlen(name) + 1;
	execbuf = xzalloc(n + 1);
	readlink(buf, execbuf, n);
	/* if readlink fails because link target is longer than strlen(name),
	 * execbuf still contains "", and strcmp will return !0. */
	n = strcmp(execbuf, name);
	if (ENABLE_FEATURE_CLEAN_UP)
		free(execbuf);
	return !n; /* nonzero (true) if execbuf == name */
}

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

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

static int pid_is_cmd(pid_t pid, const char *name)
{
	char fname[sizeof("/proc//stat") + sizeof(int)*3];
	char *buf;
	int r = 0;

	sprintf(fname, "/proc/%u/stat", pid);
	buf = xmalloc_open_read_close(fname, NULL);
	if (buf) {
		char *p = strchr(buf, '(');
		if (p) {
			char *pe = strrchr(++p, ')');
			if (pe) {
				*pe = '\0';
				r = !strcmp(p, name);
			}
		}
		free(buf);
	}
	return r;
}

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

	if (execname && !pid_is_exec(pid, execname)) {
		return;
	}
	if (userspec && !pid_is_user(pid, user_id)) {
		return;
	}
	if (cmdname && !pid_is_cmd(pid, cmdname)) {
		return;
	}
	p = xmalloc(sizeof(*p));
	p->next = found;
	p->pid = pid;
	found = p;
}

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

	f = fopen(pidfile, "r");
	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 ((entry = readdir(procdir)) != NULL) {
		pid = bb_strtou(entry->d_name, NULL, 10);
		if (errno)
			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;

	do_procinit();

	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 (!found) {
		if (!quiet)
			printf("no %s found; none killed\n", what);
		killed = -1;
		goto ret;
	}
	for (p = found; p; p = p->next) {
		if (kill(p->pid, signal_nr) == 0) {
			p->pid = - p->pid;
			killed++;
		} else {
			bb_perror_msg("warning: killing process %u", p->pid);
		}
	}
	if (!quiet && killed) {
		printf("stopped %s (pid", what);
		for (p = found; p; p = p->next)
			if (p->pid < 0)
				printf(" %u", - 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"
	"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

enum {
	CTX_STOP       = 0x1,
	CTX_START      = 0x2,
	OPT_BACKGROUND = 0x4, // -b
	OPT_QUIET      = 0x8, // -q
	OPT_MAKEPID    = 0x10, // -m
	OPT_a          = 0x20, // -a
	OPT_n          = 0x40, // -n
	OPT_s          = 0x80, // -s
	OPT_u          = 0x100, // -u
	OPT_c          = 0x200, // -c
	OPT_x          = 0x400, // -x
	OPT_p          = 0x800, // -p
	OPT_OKNODO     = 0x1000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
	OPT_VERBOSE    = 0x2000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
	OPT_NICELEVEL  = 0x4000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
};

int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int start_stop_daemon_main(int argc, char **argv)
{
	unsigned opt;
	char *signame;
	char *startas;
	char *chuid;
#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

	/* Check required one context option was given */
	opt_complementary = "K:S:K--S:S--K:m?p:K?xpun:S?xa";
	opt = getopt32(argv, "KSbqma:n:s:u:c:x:p:"
		USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:"),
//		USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
		&startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
		USE_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
//		USE_FEATURE_START_STOP_DAEMON_FANCY(,&retry_arg)
	);

	quiet = (opt & OPT_QUIET) && !(opt & OPT_VERBOSE);

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

	if (!(opt & OPT_a))
		startas = execname;

//	USE_FEATURE_START_STOP_DAEMON_FANCY(
//		if (retry_arg)
//			retries = xatoi_u(retry_arg);
//	)
	argc -= optind;
	argv += optind;

	if (userspec) {
		user_id = bb_strtou(userspec, NULL, 10);
		if (errno)
			user_id = xuname2uid(userspec);
	}

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

	do_procinit();

	if (found) {
		if (!quiet)
			printf("%s already running\n%d\n", execname, found->pid);
		return !(opt & OPT_OKNODO);
	}
	*--argv = startas;
	if (opt & OPT_BACKGROUND) {
#if BB_MMU
		bb_daemonize(0);
#else
		pid_t pid = vfork();
		if (pid < 0) /* error */
			bb_perror_msg_and_die("vfork");
		if (pid != 0) {
			/* parent */
			/* why _exit? the child may have changed the stack,
			 * so "return 0" may do bad things */
			_exit(0);
		}
		/* 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.gid != (gid_t) -1) xsetgid(ugid.gid);
		if (ugid.uid != (uid_t) -1) xsetuid(ugid.uid);
	}
#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
	execv(startas, argv);
	bb_perror_msg_and_die("cannot start %s", startas);
}