aboutsummaryrefslogtreecommitdiff
path: root/src/rc/openrc-init.c
blob: d80386374460e3e71e6a97aa95360666a996dc5b (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
/*
 * openrc-init.c
 * This is the init process (pid 1) for OpenRC.
 *
 * This is based on code written by James Hammons <jlhamm@acm.org>, so
 * I would like to publically thank him for his work.
 */

/*
 * Copyright (c) 2017 The OpenRC Authors.
 * See the Authors file at the top-level directory of this distribution and
 * https://github.com/OpenRC/openrc/blob/master/AUTHORS
 *
 * This file is part of OpenRC. It is subject to the license terms in
 * the LICENSE file found in the top-level directory of this
 * distribution and at https://github.com/OpenRC/openrc/blob/master/LICENSE
 * This file may not be copied, modified, propagated, or distributed
 *    except according to the terms contained in the LICENSE file.
 */

#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/reboot.h>
#include <sys/wait.h>

#include "helpers.h"
#include "rc.h"
#include "rc-wtmp.h"
#include "version.h"

static const char *path_default = "/sbin:/usr/sbin:/bin:/usr/bin";
static const char *rc_default_runlevel = "default";

static pid_t do_openrc(const char *runlevel)
{
	pid_t pid;
	sigset_t signals;

	pid = fork();
	switch(pid) {
		case -1:
			perror("fork");
			break;
		case 0:
			setsid();
			/* unblock all signals */
			sigemptyset(&signals);
			sigprocmask(SIG_SETMASK, &signals, NULL);
			printf("Starting %s runlevel\n", runlevel);
			execlp("openrc", "openrc", runlevel, NULL);
			perror("exec");
			break;
		default:
			break;
	}
	return pid;
}

static void init(const char *default_runlevel)
{
	const char *runlevel = NULL;
	pid_t pid;

	pid = do_openrc("sysinit");
	waitpid(pid, NULL, 0);
	pid = do_openrc("boot");
	waitpid(pid, NULL, 0);
	if (default_runlevel)
		runlevel = default_runlevel;
	else
		runlevel = rc_conf_value("rc_default_runlevel");
	if (!runlevel)
		runlevel = rc_default_runlevel;
	if (!rc_runlevel_exists(runlevel)) {
		printf("%s is an invalid runlevel\n", runlevel);
		runlevel = rc_default_runlevel;
	}
	pid = do_openrc(runlevel);
	waitpid(pid, NULL, 0);
	log_wtmp("reboot", "~~", 0, RUN_LVL, "~~");
}

static void handle_reexec(char *my_name)
{
	execlp(my_name, my_name, "reexec", NULL);
	return;
}

static void handle_shutdown(const char *runlevel, int cmd)
{
	pid_t pid;

	pid = do_openrc(runlevel);
	while (waitpid(pid, NULL, 0) != pid);
	printf("Sending the final term signal\n");
	kill(-1, SIGTERM);
	sleep(3);
	printf("Sending the final kill signal\n");
	kill(-1, SIGKILL);
	sync();
	reboot(cmd);
}

static void handle_single(void)
{
	pid_t pid;

	pid = do_openrc("single");
	while (waitpid(pid, NULL, 0) != pid);
}

static void reap_zombies(void)
{
	pid_t pid;

	for (;;) {
		pid = waitpid(-1, NULL, WNOHANG);
		if (pid == 0)
			break;
		else if (pid == -1) {
			if (errno == ECHILD)
				break;
			perror("waitpid");
			continue;
		}
	}
}

static void signal_handler(int sig)
{
	switch(sig) {
		case SIGINT:
			handle_shutdown("reboot", RB_AUTOBOOT);
			break;
		case SIGCHLD:
			reap_zombies();
			break;
		default:
			printf("Unknown signal received, %d\n", sig);
			break;
	}
}

int main(int argc, char **argv)
{
	char *default_runlevel;
	char buf[2048];
	int count;
	FILE *fifo;
	bool reexec = false;
	sigset_t signals;
	struct sigaction sa;

	if (getpid() != 1)
		return 1;

	printf("OpenRC init version %s starting\n", VERSION);

	if (argc > 1)
		default_runlevel = argv[1];
	else
		default_runlevel = NULL;

	if (default_runlevel && strcmp(default_runlevel, "reexec") == 0)
		reexec = true;

	/* block all signals we do not handle */
	sigfillset(&signals);
	sigdelset(&signals, SIGCHLD);
	sigdelset(&signals, SIGINT);
	sigprocmask(SIG_SETMASK, &signals, NULL);

	/* install signal  handler */
	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = signal_handler;
	sigaction(SIGCHLD, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);
	reboot(RB_DISABLE_CAD);

	/* set default path */
	setenv("PATH", path_default, 1);

	if (! reexec)
		init(default_runlevel);

	if (mkfifo(RC_INIT_FIFO, 0600) == -1 && errno != EEXIST)
		perror("mkfifo");

	for (;;) {
		/* This will block until a command is sent down the pipe... */
		fifo = fopen(RC_INIT_FIFO, "r");
		if (!fifo) {
			if (errno != EINTR)
				perror("fopen");
			continue;
		}
		count = fread(buf, 1, sizeof(buf) - 1, fifo);
		buf[count] = 0;
		fclose(fifo);
		printf("PID1: Received \"%s\" from FIFO...\n", buf);
		if (strcmp(buf, "halt") == 0)
			handle_shutdown("shutdown", RB_HALT_SYSTEM);
		else if (strcmp(buf, "kexec") == 0)
			handle_shutdown("reboot", RB_KEXEC);
		else if (strcmp(buf, "poweroff") == 0)
			handle_shutdown("shutdown", RB_POWER_OFF);
		else if (strcmp(buf, "reboot") == 0)
			handle_shutdown("reboot", RB_AUTOBOOT);
		else if (strcmp(buf, "reexec") == 0)
			handle_reexec(argv[0]);
		else if (strcmp(buf, "single") == 0)
			handle_single();
	}
	return 0;
}