1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file daemon.c Some helpers for programs that detach from the console. */
7 #include <sys/types.h> /* getgrnam() */
10 #include <sys/resource.h>
17 /** The internal state of the daemon. */
19 /** See \ref daemon_flags. */
21 /** Set by \ref daemon_set_logfile(). */
23 /** Current loglevel, see \ref daemon_set_loglevel(). */
25 /** Used by \ref server_uptime() and \ref uptime_str(). */
27 /** The file pointer if the logfile is open. */
29 /** Used by para_log() if \p DF_LOG_HOSTNAME is set. */
31 /** Used for colored log messages. */
32 char log_colors[NUM_LOGLEVELS][COLOR_MAXLEN];
35 * If these pointers are non-NULL, the functions are called from
36 * daemon_log() before and after writing each log message.
38 void (*pre_log_hook)(void);
39 void (*post_log_hook)(void);
42 static struct daemon the_daemon, *me = &the_daemon;
44 static void daemon_set_default_log_colors(void)
47 static const char *default_log_colors[NUM_LOGLEVELS] = {
48 [LL_DEBUG] = "normal",
50 [LL_NOTICE] = "normal",
51 [LL_WARNING] = "yellow",
53 [LL_CRIT] = "magenta bold",
54 [LL_EMERG] = "red bold",
56 for (i = 0; i < NUM_LOGLEVELS; i++)
57 color_parse_or_die(default_log_colors[i], me->log_colors[i]);
61 * Set the color for log messages of the given severity level.
63 * \param arg Must be of the form "severity:[fg [bg]] [attr]".
65 void daemon_set_log_color_or_die(const char *arg)
67 char *p = strchr(arg, ':');
72 ret = get_loglevel_by_name(arg);
77 color_parse_or_die(p, me->log_colors[ll]);
80 PARA_EMERG_LOG("%s: invalid color argument\n", arg);
85 * Initialize color mode if necessary.
87 * \param color_arg The argument given to --color.
88 * \param color_arg_auto The value for automatic color detection.
89 * \param color_arg_no The value to disable colored log messages.
90 * \param logfile_given In auto mode colors are disabled if this value is true.
92 * If color_arg equals color_arg_no, color mode is disabled. That is, calls to
93 * para_log() will not produce colored output. If color_arg equals
94 * color_arg_auto, the function detects automatically whether to activate
95 * colors. Otherwise color mode is enabled.
97 * If color mode is to be enabled, the default colors are set for each
98 * loglevel. They can be overwritten by calling daemon_set_log_color_or_die().
100 * \return Whether colors have been enabled by the function.
102 bool daemon_init_colors_or_die(int color_arg, int color_arg_auto,
103 int color_arg_no, bool logfile_given)
105 if (color_arg == color_arg_no)
107 if (color_arg == color_arg_auto) {
110 if (!isatty(STDERR_FILENO))
113 daemon_set_flag(DF_COLOR_LOG);
114 daemon_set_default_log_colors();
119 * Init or change the name of the log file.
121 * \param logfile_name The full path of the logfile.
123 void daemon_set_logfile(const char *logfile_name)
125 free(me->logfile_name);
126 me->logfile_name = NULL;
129 if (me->old_cwd && logfile_name[0] != '/')
130 me->logfile_name = make_message("%s/%s", me->old_cwd,
133 me->logfile_name = para_strdup(logfile_name);
137 * Control the verbosity for logging.
139 * This instructs the daemon to not log subsequent messages whose severity is
140 * lower than the given value.
142 * \param loglevel The new log level.
144 void daemon_set_loglevel(int loglevel)
146 assert(loglevel >= 0);
147 assert(loglevel < NUM_LOGLEVELS);
148 me->loglevel = loglevel;
153 * Register functions to be called before and after a message is logged.
155 * \param pre_log_hook Called before the message is logged.
156 * \param post_log_hook Called after the message is logged.
158 * The purpose of this function is to provide a primitive for multi-threaded
159 * applications to serialize the access to the log facility, preventing
160 * interleaving log messages. This can be achieved by having the pre-log hook
161 * acquire a lock which blocks the other threads on the attempt to log a
162 * message at the same time. The post-log hook is responsible for releasing
165 * If these hooks are unnecessary, for example because the application is
166 * single-threaded, this function does not need to be called.
168 void daemon_set_hooks(void (*pre_log_hook)(void), void (*post_log_hook)(void))
170 me->pre_log_hook = pre_log_hook;
171 me->post_log_hook = post_log_hook;
175 * Set one of the daemon config flags.
177 * \param flag The flag to set.
179 * \sa \ref daemon_flags.
181 void daemon_set_flag(unsigned flag)
186 static bool daemon_test_flag(unsigned flag)
188 return me->flags & flag;
192 * Do the usual stuff to become a daemon.
194 * \param parent_waits Whether the parent process should pause before exit.
196 * Fork, become session leader, cd to /, and dup fd 0, 1, 2 to /dev/null. If \a
197 * parent_waits is false, the parent process terminates immediately.
198 * Otherwise, a pipe is created prior to the fork() and the parent tries to
199 * read a single byte from the reading end of the pipe. The child is supposed
200 * to write to the writing end of the pipe after it completed its setup
201 * procedure successfully. This behaviour is useful to let the parent process
202 * die with an error if the child process aborts early, since in this case the
203 * read() will return non-positive.
205 * \return This function either succeeds or calls exit(3). If parent_waits is
206 * true, the return value is the file descriptor of the writing end of the
207 * pipe. Otherwise the function returns zero.
209 * \sa fork(2), setsid(2), dup(2), pause(2).
211 int daemonize(bool parent_waits)
214 int null, pipe_fd[2];
216 if (parent_waits && pipe(pipe_fd) < 0)
218 PARA_INFO_LOG("subsequent log messages go to %s\n", me->logfile_name?
219 me->logfile_name : "/dev/null");
223 if (pid) { /* parent exits */
227 exit(read(pipe_fd[0], &c, 1) <= 0?
228 EXIT_FAILURE : EXIT_SUCCESS);
234 /* become session leader */
237 me->old_cwd = getcwd(NULL, 0);
240 null = open("/dev/null", O_RDWR);
243 if (dup2(null, STDIN_FILENO) < 0)
245 if (dup2(null, STDOUT_FILENO) < 0)
247 if (dup2(null, STDERR_FILENO) < 0)
250 return parent_waits? pipe_fd[1] : 0;
252 PARA_EMERG_LOG("fatal: %s\n", strerror(errno));
257 * Close the log file of the daemon.
259 void daemon_close_log(void)
263 PARA_INFO_LOG("closing logfile\n");
269 * fopen() the logfile in append mode.
271 * \return Either succeeds or exits.
273 void daemon_open_log_or_die(void)
277 if (!me->logfile_name)
279 new_log = fopen(me->logfile_name, "a");
281 PARA_EMERG_LOG("can not open %s: %s\n", me->logfile_name,
286 me->logfile = new_log;
287 /* equivalent to setlinebuf(), but portable */
288 setvbuf(me->logfile, NULL, _IOLBF, 0);
292 * Log the startup message containing the paraslash version.
294 * \param name The name of the executable.
296 * First the given \a name is prefixed with the string "para_". Next the git
297 * version is appended. The resulting string is logged with priority "INFO".
299 void daemon_log_welcome(const char *name)
301 PARA_INFO_LOG("welcome to para_%s-" PACKAGE_VERSION " \n", name);
305 * Renice the calling process.
307 * \param prio The priority value to set.
309 * Errors are not considered fatal, but a warning message is logged if the
310 * underlying call to setpriority(2) fails.
312 void daemon_set_priority(int prio)
314 if (setpriority(PRIO_PROCESS, 0, prio) < 0)
315 PARA_WARNING_LOG("could not set priority to %d: %s\n", prio,
320 * Give up superuser privileges.
322 * \param username The user to switch to.
323 * \param groupname The group to switch to.
325 * This function returns immediately if not invoked with EUID zero. Otherwise,
326 * it tries to obtain the GID of \a groupname and the UID of \a username. On
327 * success, effective and real GID/UID and the saved set-group-ID/set-user-ID
328 * are all set accordingly. On errors, an appropriate message is logged and
329 * exit() is called to terminate the process.
331 * \sa getpwnam(3), getuid(2), setuid(2), getgrnam(2), setgid(2)
333 void daemon_drop_privileges_or_die(const char *username, const char *groupname)
341 struct group *g = getgrnam(groupname);
343 PARA_EMERG_LOG("failed to get group %s: %s\n",
344 groupname, strerror(errno));
347 if (setgid(g->gr_gid) < 0) {
348 PARA_EMERG_LOG("failed to set group id %d: %s\n",
349 (int)g->gr_gid, strerror(errno));
354 PARA_EMERG_LOG("root privileges, but no user option given\n");
357 tmp = para_strdup(username);
361 PARA_EMERG_LOG("%s: no such user\n", username);
364 PARA_INFO_LOG("dropping root privileges\n");
365 if (setuid(p->pw_uid) < 0) {
366 PARA_EMERG_LOG("failed to set effective user ID (%s)",
370 PARA_DEBUG_LOG("uid: %d, euid: %d\n", (int)getuid(), (int)geteuid());
374 * Set the startup time.
376 * This should be called once on startup. It sets the start time to the
377 * current time. The stored time is used for retrieving the server uptime.
379 * \sa time(2), \ref daemon_get_uptime(), \ref daemon_get_uptime_str().
381 void daemon_set_start_time(void)
383 time(&me->startuptime);
389 * \param current_time The current time.
391 * The \a current_time pointer may be \p NULL. In this case the function
392 * obtains the current time from the system.
394 * \return This returns the server uptime in seconds, i.e. the difference
395 * between the current time and the value stored previously via \ref
396 * daemon_set_start_time().
398 time_t daemon_get_uptime(const struct timeval *current_time)
403 return current_time->tv_sec - me->startuptime;
405 return difftime(t, me->startuptime);
409 * Construct a string containing the current uptime.
411 * \param current_time See a \ref daemon_get_uptime().
413 * \return A dynamically allocated string of the form "days:hours:minutes".
415 __malloc char *daemon_get_uptime_str(const struct timeval *current_time)
417 long t = daemon_get_uptime(current_time);
418 return make_message("%li:%02li:%02li", t / 86400,
419 (t / 3600) % 24, (t / 60) % 60);
423 * The log function for para_server and para_audiod.
425 * \param ll The log level.
426 * \param fmt The format string describing the log message.
428 __printf_2_3 void daemon_log(int ll, const char* fmt,...)
434 bool log_time = daemon_test_flag(DF_LOG_TIME), log_timing =
435 daemon_test_flag(DF_LOG_TIMING);
437 ll = PARA_MIN(ll, NUM_LOGLEVELS - 1);
438 ll = PARA_MAX(ll, LL_DEBUG);
439 if (ll < me->loglevel)
442 fp = me->logfile? me->logfile : stderr;
443 if (me->pre_log_hook)
445 color = daemon_test_flag(DF_COLOR_LOG)? me->log_colors[ll] : NULL;
447 fprintf(fp, "%s", color);
448 if (log_time || log_timing) {
450 clock_get_realtime(&tv);
451 if (daemon_test_flag(DF_LOG_TIME)) { /* print date and time */
452 time_t t1 = tv.tv_sec;
455 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
456 fprintf(fp, "%s%s", str, log_timing? ":" : " ");
458 if (log_timing) /* print milliseconds */
459 fprintf(fp, "%04lu ", (long unsigned)tv.tv_usec / 1000);
461 if (daemon_test_flag(DF_LOG_HOSTNAME)) {
463 me->hostname = para_hostname();
464 fprintf(fp, "%s ", me->hostname);
466 if (daemon_test_flag(DF_LOG_LL)) /* log loglevel */
467 fprintf(fp, "(%d) ", ll);
468 if (daemon_test_flag(DF_LOG_PID)) { /* log pid */
469 pid_t mypid = getpid();
470 fprintf(fp, "(%d) ", (int)mypid);
473 vfprintf(fp, fmt, argp);
476 fprintf(fp, "%s", COLOR_RESET);
477 if (me->post_log_hook)