charon: Ignore an existing PID file if it references ourself
[strongswan.git] / src / charon / charon.c
1 /*
2 * Copyright (C) 2006-2017 Tobias Brunner
3 * Copyright (C) 2005-2009 Martin Willi
4 * Copyright (C) 2006 Daniel Roethlisberger
5 * Copyright (C) 2005 Jan Hutter
6 * HSR Hochschule fuer Technik Rapperswil
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
12 *
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 * for more details.
17 */
18
19 #include <stdio.h>
20 #include <signal.h>
21 #include <pthread.h>
22 #include <sys/stat.h>
23 #include <sys/types.h>
24 #include <sys/utsname.h>
25 #include <unistd.h>
26 #include <getopt.h>
27 #include <fcntl.h>
28 #include <errno.h>
29
30 #include <daemon.h>
31
32 #include <library.h>
33 #include <utils/backtrace.h>
34 #include <threading/thread.h>
35
36 #ifdef ANDROID
37 #include <private/android_filesystem_config.h> /* for AID_VPN */
38 #endif
39
40 /**
41 * PID file, in which charon stores its process id
42 */
43 #define PID_FILE IPSEC_PIDDIR "/charon.pid"
44
45 /**
46 * Default user and group
47 */
48 #ifndef IPSEC_USER
49 #define IPSEC_USER NULL
50 #endif
51
52 #ifndef IPSEC_GROUP
53 #define IPSEC_GROUP NULL
54 #endif
55
56 /**
57 * Global reference to PID file (required to truncate, if undeletable)
58 */
59 static FILE *pidfile = NULL;
60
61 /**
62 * hook in library for debugging messages
63 */
64 extern void (*dbg) (debug_t group, level_t level, char *fmt, ...);
65
66 /**
67 * Logging hook for library logs, using stderr output
68 */
69 static void dbg_stderr(debug_t group, level_t level, char *fmt, ...)
70 {
71 va_list args;
72
73 if (level <= 1)
74 {
75 va_start(args, fmt);
76 fprintf(stderr, "00[%N] ", debug_names, group);
77 vfprintf(stderr, fmt, args);
78 fprintf(stderr, "\n");
79 va_end(args);
80 }
81 }
82
83 /**
84 * Run the daemon and handle unix signals
85 */
86 static void run()
87 {
88 sigset_t set;
89
90 /* handle SIGINT, SIGHUP and SIGTERM in this handler */
91 sigemptyset(&set);
92 sigaddset(&set, SIGINT);
93 sigaddset(&set, SIGHUP);
94 sigaddset(&set, SIGTERM);
95 sigprocmask(SIG_BLOCK, &set, NULL);
96
97 while (TRUE)
98 {
99 int sig;
100
101 sig = sigwaitinfo(&set, NULL);
102 if (sig == -1)
103 {
104 if (errno == EINTR)
105 { /* ignore signals we didn't wait for */
106 continue;
107 }
108 DBG1(DBG_DMN, "waiting for signal failed: %s", strerror(errno));
109 return;
110 }
111 switch (sig)
112 {
113 case SIGHUP:
114 {
115 DBG1(DBG_DMN, "signal of type SIGHUP received. Reloading "
116 "configuration");
117 if (lib->settings->load_files(lib->settings, lib->conf, FALSE))
118 {
119 charon->load_loggers(charon);
120 lib->plugins->reload(lib->plugins, NULL);
121 }
122 else
123 {
124 DBG1(DBG_DMN, "reloading config failed, keeping old");
125 }
126 break;
127 }
128 case SIGINT:
129 {
130 DBG1(DBG_DMN, "signal of type SIGINT received. Shutting down");
131 charon->bus->alert(charon->bus, ALERT_SHUTDOWN_SIGNAL, sig);
132 return;
133 }
134 case SIGTERM:
135 {
136 DBG1(DBG_DMN, "signal of type SIGTERM received. Shutting down");
137 charon->bus->alert(charon->bus, ALERT_SHUTDOWN_SIGNAL, sig);
138 return;
139 }
140 }
141 }
142 }
143
144 /**
145 * lookup UID and GID
146 */
147 static bool lookup_uid_gid()
148 {
149 char *name;
150
151 name = lib->settings->get_str(lib->settings, "charon.user", IPSEC_USER);
152 if (name && !lib->caps->resolve_uid(lib->caps, name))
153 {
154 return FALSE;
155 }
156 name = lib->settings->get_str(lib->settings, "charon.group", IPSEC_GROUP);
157 if (name && !lib->caps->resolve_gid(lib->caps, name))
158 {
159 return FALSE;
160 }
161 #ifdef ANDROID
162 lib->caps->set_uid(lib->caps, AID_VPN);
163 #endif
164 return TRUE;
165 }
166
167 /**
168 * Handle SIGSEGV/SIGILL signals raised by threads
169 */
170 static void segv_handler(int signal)
171 {
172 backtrace_t *backtrace;
173
174 DBG1(DBG_DMN, "thread %u received %d", thread_current_id(), signal);
175 backtrace = backtrace_create(2);
176 backtrace->log(backtrace, NULL, TRUE);
177 backtrace->log(backtrace, stderr, TRUE);
178 backtrace->destroy(backtrace);
179
180 DBG1(DBG_DMN, "killing ourself, received critical signal");
181 abort();
182 }
183
184 /**
185 * Check/create PID file, return TRUE if already running
186 */
187 static bool check_pidfile()
188 {
189 struct stat stb;
190
191 if (stat(PID_FILE, &stb) == 0)
192 {
193 pidfile = fopen(PID_FILE, "r");
194 if (pidfile)
195 {
196 char buf[64];
197 pid_t pid = 0;
198
199 memset(buf, 0, sizeof(buf));
200 if (fread(buf, 1, sizeof(buf), pidfile))
201 {
202 buf[sizeof(buf) - 1] = '\0';
203 pid = atoi(buf);
204 }
205 fclose(pidfile);
206 pidfile = NULL;
207 if (pid && pid != getpid() && kill(pid, 0) == 0)
208 {
209 DBG1(DBG_DMN, "charon already running ('"PID_FILE"' exists)");
210 return TRUE;
211 }
212 }
213 DBG1(DBG_DMN, "removing pidfile '"PID_FILE"', process not running");
214 unlink(PID_FILE);
215 }
216
217 /* create new pidfile */
218 pidfile = fopen(PID_FILE, "w");
219 if (pidfile)
220 {
221 int fd;
222
223 fd = fileno(pidfile);
224 if (fd == -1)
225 {
226 DBG1(DBG_DMN, "unable to determine fd for '"PID_FILE"'");
227 return TRUE;
228 }
229 if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
230 {
231 DBG1(DBG_LIB, "setting FD_CLOEXEC for '"PID_FILE"' failed: %s",
232 strerror(errno));
233 }
234 ignore_result(fchown(fd,
235 lib->caps->get_uid(lib->caps),
236 lib->caps->get_gid(lib->caps)));
237 fprintf(pidfile, "%d\n", getpid());
238 fflush(pidfile);
239 return FALSE;
240 }
241 else
242 {
243 DBG1(DBG_DMN, "unable to create pidfile '"PID_FILE"'");
244 return TRUE;
245 }
246 }
247
248 /**
249 * Delete/truncate the PID file
250 */
251 static void unlink_pidfile()
252 {
253 /* because unlinking the PID file may fail, we truncate it to ensure the
254 * daemon can be properly restarted. one probable cause for this is the
255 * combination of not running as root and the effective user lacking
256 * permissions on the parent dir(s) of the PID file */
257 if (pidfile)
258 {
259 ignore_result(ftruncate(fileno(pidfile), 0));
260 fclose(pidfile);
261 unlink(PID_FILE);
262 }
263 }
264
265 /**
266 * print command line usage and exit
267 */
268 static void usage(const char *msg)
269 {
270 if (msg != NULL && *msg != '\0')
271 {
272 fprintf(stderr, "%s\n", msg);
273 }
274 fprintf(stderr, "Usage: charon\n"
275 " [--help]\n"
276 " [--version]\n"
277 " [--use-syslog]\n"
278 " [--debug-<type> <level>]\n"
279 " <type>: log context type (dmn|mgr|ike|chd|job|cfg|knl|net|asn|enc|tnc|imc|imv|pts|tls|esp|lib)\n"
280 " <level>: log verbosity (-1 = silent, 0 = audit, 1 = control,\n"
281 " 2 = controlmore, 3 = raw, 4 = private)\n"
282 "\n"
283 );
284 }
285
286 /**
287 * Main function, starts the daemon.
288 */
289 int main(int argc, char *argv[])
290 {
291 struct sigaction action;
292 int group, status = SS_RC_INITIALIZATION_FAILED;
293 struct utsname utsname;
294 level_t levels[DBG_MAX];
295 bool use_syslog = FALSE;
296
297 /* logging for library during initialization, as we have no bus yet */
298 dbg = dbg_stderr;
299
300 /* initialize library */
301 if (!library_init(NULL, "charon"))
302 {
303 library_deinit();
304 exit(SS_RC_LIBSTRONGSWAN_INTEGRITY);
305 }
306
307 if (lib->integrity &&
308 !lib->integrity->check_file(lib->integrity, "charon", argv[0]))
309 {
310 dbg_stderr(DBG_DMN, 1, "integrity check of charon failed");
311 library_deinit();
312 exit(SS_RC_DAEMON_INTEGRITY);
313 }
314
315 if (!libcharon_init())
316 {
317 dbg_stderr(DBG_DMN, 1, "initialization failed - aborting charon");
318 goto deinit;
319 }
320
321 /* use CTRL loglevel for default */
322 for (group = 0; group < DBG_MAX; group++)
323 {
324 levels[group] = LEVEL_CTRL;
325 }
326
327 /* handle arguments */
328 for (;;)
329 {
330 struct option long_opts[] = {
331 { "help", no_argument, NULL, 'h' },
332 { "version", no_argument, NULL, 'v' },
333 { "use-syslog", no_argument, NULL, 'l' },
334 /* TODO: handle "debug-all" */
335 { "debug-dmn", required_argument, &group, DBG_DMN },
336 { "debug-mgr", required_argument, &group, DBG_MGR },
337 { "debug-ike", required_argument, &group, DBG_IKE },
338 { "debug-chd", required_argument, &group, DBG_CHD },
339 { "debug-job", required_argument, &group, DBG_JOB },
340 { "debug-cfg", required_argument, &group, DBG_CFG },
341 { "debug-knl", required_argument, &group, DBG_KNL },
342 { "debug-net", required_argument, &group, DBG_NET },
343 { "debug-asn", required_argument, &group, DBG_ASN },
344 { "debug-enc", required_argument, &group, DBG_ENC },
345 { "debug-tnc", required_argument, &group, DBG_TNC },
346 { "debug-imc", required_argument, &group, DBG_IMC },
347 { "debug-imv", required_argument, &group, DBG_IMV },
348 { "debug-pts", required_argument, &group, DBG_PTS },
349 { "debug-tls", required_argument, &group, DBG_TLS },
350 { "debug-esp", required_argument, &group, DBG_ESP },
351 { "debug-lib", required_argument, &group, DBG_LIB },
352 { 0,0,0,0 }
353 };
354
355 int c = getopt_long(argc, argv, "", long_opts, NULL);
356 switch (c)
357 {
358 case EOF:
359 break;
360 case 'h':
361 usage(NULL);
362 status = 0;
363 goto deinit;
364 case 'v':
365 printf("Linux strongSwan %s\n", VERSION);
366 status = 0;
367 goto deinit;
368 case 'l':
369 use_syslog = TRUE;
370 continue;
371 case 0:
372 /* option is in group */
373 levels[group] = atoi(optarg);
374 continue;
375 default:
376 usage("");
377 status = 1;
378 goto deinit;
379 }
380 break;
381 }
382
383 if (!lookup_uid_gid())
384 {
385 dbg_stderr(DBG_DMN, 1, "invalid uid/gid - aborting charon");
386 goto deinit;
387 }
388
389 charon->set_default_loggers(charon, levels, !use_syslog);
390 charon->load_loggers(charon);
391
392 if (uname(&utsname) != 0)
393 {
394 memset(&utsname, 0, sizeof(utsname));
395 }
396 DBG1(DBG_DMN, "Starting IKE charon daemon (strongSwan "VERSION", %s %s, %s)",
397 utsname.sysname, utsname.release, utsname.machine);
398 if (lib->integrity)
399 {
400 DBG1(DBG_DMN, "integrity tests enabled:");
401 DBG1(DBG_DMN, "lib 'libstrongswan': passed file and segment integrity tests");
402 DBG1(DBG_DMN, "lib 'libcharon': passed file and segment integrity tests");
403 DBG1(DBG_DMN, "daemon 'charon': passed file integrity test");
404 }
405
406 /* initialize daemon */
407 if (!charon->initialize(charon,
408 lib->settings->get_str(lib->settings, "charon.load", PLUGINS)))
409 {
410 DBG1(DBG_DMN, "initialization failed - aborting charon");
411 goto deinit;
412 }
413 lib->plugins->status(lib->plugins, LEVEL_CTRL);
414
415 if (check_pidfile())
416 {
417 goto deinit;
418 }
419
420 if (!lib->caps->drop(lib->caps))
421 {
422 DBG1(DBG_DMN, "capability dropping failed - aborting charon");
423 goto deinit;
424 }
425
426 /* add handler for SEGV and ILL,
427 * INT, TERM and HUP are handled by sigwaitinfo() in run() */
428 action.sa_handler = segv_handler;
429 action.sa_flags = 0;
430 sigemptyset(&action.sa_mask);
431 sigaddset(&action.sa_mask, SIGINT);
432 sigaddset(&action.sa_mask, SIGTERM);
433 sigaddset(&action.sa_mask, SIGHUP);
434 sigaction(SIGSEGV, &action, NULL);
435 sigaction(SIGILL, &action, NULL);
436 sigaction(SIGBUS, &action, NULL);
437 action.sa_handler = SIG_IGN;
438 sigaction(SIGPIPE, &action, NULL);
439
440 pthread_sigmask(SIG_SETMASK, &action.sa_mask, NULL);
441
442 /* start daemon (i.e. the threads in the thread-pool) */
443 charon->start(charon);
444
445 /* main thread goes to run loop */
446 run();
447
448 status = 0;
449
450 deinit:
451 libcharon_deinit();
452 unlink_pidfile();
453 library_deinit();
454 return status;
455 }