aboutsummaryrefslogtreecommitdiff
path: root/debianutils/start_stop_daemon.c
blob: 29e3d86732ad72c855fe36a0ad3a7ca64c5d7137 (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
/* vi: set sw=4 ts=4: */
/*
 * Mini start-stop-daemon implementation(s) for busybox
 *
 * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
 * public domain.
 * Adapted for busybox David Kimdon <dwhedon@gordian.com>
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <signal.h>
#include <errno.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>

#include "busybox.h"
#include "pwd.h"

static int start = 0;
static int stop = 0;
static int fork_before_exec = 0;
static int signal_nr = 15;
static int user_id = -1;
static const char *userspec = NULL;
static const char *cmdname = NULL;
static char *execname = NULL;
static char *startas = NULL;

typedef struct pid_list {
	struct pid_list *next;
	int pid;
} pid_list;

static pid_list *found = NULL;

static inline void
push(int pid)
{
	pid_list *p;

	p = xmalloc(sizeof(*p));
	p->next = found;
	p->pid = pid;
	found = p;
}


static void
parse_options(int argc, char * const *argv)
{
	
	int c;

	for (;;) {
	    c = getopt (argc, argv, "a:n:s:u:x:KSb");
		if (c == EOF)
			break;
		switch (c) {
		case 'K':
			stop = 1;
			break;
		case 'S':
			start = 1;
			break;
		case 'a':
			startas = optarg;
			break;
		case 'n':
			cmdname = optarg;
			break;
		case 's':
			if (sscanf(optarg, "%d", &signal_nr) != 1)
				error_msg_and_die ("-s takes a numeric argument");
			break;
		case 'u':
			userspec = optarg;
			break;
		case 'x':
			execname = optarg;
			break;
		case 'b':
			fork_before_exec = 1;
			break;
		default:
			show_usage();
		}
	}

	if (start == stop)
		error_msg_and_die ("need one of -S or -K");

	if (!execname && !userspec)
		error_msg_and_die ("need at least one of -x or -u");

	if (!startas)
		startas = execname;

	if (start && !startas)
		error_msg_and_die ("-S needs -x or -a");
}


static int
pid_is_exec(int pid, const char *exec)
{
	char buf[PATH_MAX];
	FILE *fp;

	sprintf(buf, "/proc/%d/cmdline", pid);
	fp = fopen(buf, "r");
	if (fp && fgets (buf, sizeof (buf), fp) ) {
	    if (strncmp (buf, exec, strlen(exec)) == 0)
		return 1;
	}
	return 0;
}


static int
pid_is_user(int pid, int uid)
{
	struct stat sb;
	char buf[32];

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


static int
pid_is_cmd(int pid, const char *name)
{
	char buf[32];
	FILE *f;
	int c;

	sprintf(buf, "/proc/%d/stat", pid);
	f = fopen(buf, "r");
	if (!f)
		return 0;
	while ((c = getc(f)) != EOF && c != '(')
		;
	if (c != '(') {
		fclose(f);
		return 0;
	}
	/* this hopefully handles command names containing ')' */
	while ((c = getc(f)) != EOF && c == *name)
		name++;
	fclose(f);
	return (c == ')' && *name == '\0');
}


static void
check(int pid)
{
	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;
	}
	push(pid);
}



static void
do_procfs(void)
{
	DIR *procdir;
	struct dirent *entry;
	int foundany, pid;

	procdir = opendir("/proc");
	if (!procdir)
		perror_msg_and_die ("opendir /proc");

	foundany = 0;
	while ((entry = readdir(procdir)) != NULL) {
		if (sscanf(entry->d_name, "%d", &pid) != 1)
			continue;
		foundany++;
		check(pid);
	}
	closedir(procdir);
	if (!foundany)
		error_msg_and_die ("nothing in /proc - not mounted?");
}


static void
do_stop(void)
{
	char what[1024];
	pid_list *p;
	int killed = 0;

	if (cmdname)
		strcpy(what, cmdname);
	else if (execname)
		strcpy(what, execname);
	else if (userspec)
		sprintf(what, "process(es) owned by `%s'", userspec);
	else
		error_msg_and_die ("internal error, please report");

	if (!found) {
		printf("no %s found; none killed.\n", what);
		return;
	}
	for (p = found; p; p = p->next) {
		if (kill(p->pid, signal_nr) == 0) {
			p->pid = -p->pid;
			killed++;
		} else {
			perror_msg("warning: failed to kill %d:", p->pid);
		}
	}
	if (killed) {
		printf("stopped %s (pid", what);
		for (p = found; p; p = p->next)
			if(p->pid < 0)
				printf(" %d", -p->pid);
		printf(").\n");
	}
}


int
start_stop_daemon_main(int argc, char **argv)
{
	parse_options(argc, argv);
	argc -= optind;
	argv += optind;

	if (userspec && sscanf(userspec, "%d", &user_id) != 1)
		user_id = my_getpwnam(userspec);

	do_procfs();

	if (stop) {
		do_stop();
		return EXIT_SUCCESS;
	}

	if (found) {
		printf("%s already running.\n%d\n", execname ,found->pid);
		return EXIT_SUCCESS;
	}
	*--argv = startas;
	if (fork_before_exec) {
		if (daemon(0, 0) == -1)
			perror_msg_and_die ("unable to fork");
	}
	setsid();
	execv(startas, argv);
	perror_msg_and_die ("unable to start %s", startas);
}