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 one loglevel.
63 * \param arg Must be of the form "ll:[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 * Suppress log messages with severity lower than the given loglevel.
139 * \param loglevel The smallest level that should be logged.
141 void daemon_set_loglevel(const char *loglevel)
143 int ret = get_loglevel_by_name(loglevel);
149 void daemon_set_hooks(void (*pre_log_hook)(void), void (*post_log_hook)(void))
151 me->pre_log_hook = pre_log_hook;
152 me->post_log_hook = post_log_hook;
156 * Set one of the daemon config flags.
158 * \param flag The flag to set.
160 * \sa \ref daemon_flags.
162 void daemon_set_flag(unsigned flag)
167 static bool daemon_test_flag(unsigned flag)
169 return me->flags & flag;
173 * Do the usual stuff to become a daemon.
175 * \param parent_waits Whether the parent process should pause before exit.
177 * Fork, become session leader, cd to /, and dup fd 0, 1, 2 to /dev/null. If \a
178 * parent_waits is false, the parent process terminates immediately.
179 * Otherwise, a pipe is created prior to the fork() and the parent tries to
180 * read a single byte from the reading end of the pipe. The child is supposed
181 * to write to the writing end of the pipe after it completed its setup
182 * procedure successfully. This behaviour is useful to let the parent process
183 * die with an error if the child process aborts early, since in this case the
184 * read() will return non-positive.
186 * \return This function either succeeds or calls exit(3). If parent_waits is
187 * true, the return value is the file descriptor of the writing end of the
188 * pipe. Otherwise the function returns zero.
190 * \sa fork(2), setsid(2), dup(2), pause(2).
192 int daemonize(bool parent_waits)
195 int null, pipe_fd[2];
197 if (parent_waits && pipe(pipe_fd) < 0)
199 PARA_INFO_LOG("subsequent log messages go to %s\n", me->logfile_name?
200 me->logfile_name : "/dev/null");
204 if (pid) { /* parent exits */
208 exit(read(pipe_fd[0], &c, 1) <= 0?
209 EXIT_FAILURE : EXIT_SUCCESS);
215 /* become session leader */
218 me->old_cwd = getcwd(NULL, 0);
221 null = open("/dev/null", O_RDWR);
224 if (dup2(null, STDIN_FILENO) < 0)
226 if (dup2(null, STDOUT_FILENO) < 0)
228 if (dup2(null, STDERR_FILENO) < 0)
231 return parent_waits? pipe_fd[1] : 0;
233 PARA_EMERG_LOG("fatal: %s\n", strerror(errno));
238 * Close the log file of the daemon.
240 void daemon_close_log(void)
244 PARA_INFO_LOG("closing logfile\n");
250 * fopen() the logfile in append mode.
252 * \return Either succeeds or exits.
254 void daemon_open_log_or_die(void)
258 if (!me->logfile_name)
260 new_log = fopen(me->logfile_name, "a");
262 PARA_EMERG_LOG("can not open %s: %s\n", me->logfile_name,
267 me->logfile = new_log;
268 /* equivalent to setlinebuf(), but portable */
269 setvbuf(me->logfile, NULL, _IOLBF, 0);
273 * Log the startup message containing the paraslash version.
275 * \param name The name of the executable.
277 * First the given \a name is prefixed with the string "para_". Next the git
278 * version is appended. The resulting string is logged with priority "INFO".
280 void daemon_log_welcome(const char *name)
282 PARA_INFO_LOG("welcome to para_%s-" PACKAGE_VERSION " \n", name);
286 * Renice the calling process.
288 * \param prio The priority value to set.
290 * Errors are not considered fatal, but a warning message is logged if the
291 * underlying call to setpriority(2) fails.
293 void daemon_set_priority(int prio)
295 if (setpriority(PRIO_PROCESS, 0, prio) < 0)
296 PARA_WARNING_LOG("could not set priority to %d: %s\n", prio,
301 * Give up superuser privileges.
303 * \param username The user to switch to.
304 * \param groupname The group to switch to.
306 * This function returns immediately if not invoked with EUID zero. Otherwise,
307 * it tries to obtain the GID of \a groupname and the UID of \a username. On
308 * success, effective and real GID/UID and the saved set-group-ID/set-user-ID
309 * are all set accordingly. On errors, an appropriate message is logged and
310 * exit() is called to terminate the process.
312 * \sa getpwnam(3), getuid(2), setuid(2), getgrnam(2), setgid(2)
314 void daemon_drop_privileges_or_die(const char *username, const char *groupname)
322 struct group *g = getgrnam(groupname);
324 PARA_EMERG_LOG("failed to get group %s: %s\n",
325 groupname, strerror(errno));
328 if (setgid(g->gr_gid) < 0) {
329 PARA_EMERG_LOG("failed to set group id %d: %s\n",
330 (int)g->gr_gid, strerror(errno));
335 PARA_EMERG_LOG("root privileges, but no user option given\n");
338 tmp = para_strdup(username);
342 PARA_EMERG_LOG("%s: no such user\n", username);
345 PARA_INFO_LOG("dropping root privileges\n");
346 if (setuid(p->pw_uid) < 0) {
347 PARA_EMERG_LOG("failed to set effective user ID (%s)",
351 PARA_DEBUG_LOG("uid: %d, euid: %d\n", (int)getuid(), (int)geteuid());
355 * Set the startup time.
357 * This should be called once on startup. It sets the start time to the
358 * current time. The stored time is used for retrieving the server uptime.
360 * \sa time(2), \ref daemon_get_uptime(), \ref daemon_get_uptime_str().
362 void daemon_set_start_time(void)
364 time(&me->startuptime);
370 * \param current_time The current time.
372 * The \a current_time pointer may be \p NULL. In this case the function
373 * obtains the current time from the system.
375 * \return This returns the server uptime in seconds, i.e. the difference
376 * between the current time and the value stored previously via \ref
377 * daemon_set_start_time().
379 time_t daemon_get_uptime(const struct timeval *current_time)
384 return current_time->tv_sec - me->startuptime;
386 return difftime(t, me->startuptime);
390 * Construct a string containing the current uptime.
392 * \param current_time See a \ref daemon_get_uptime().
394 * \return A dynamically allocated string of the form "days:hours:minutes".
396 __malloc char *daemon_get_uptime_str(const struct timeval *current_time)
398 long t = daemon_get_uptime(current_time);
399 return make_message("%li:%02li:%02li", t / 86400,
400 (t / 3600) % 24, (t / 60) % 60);
404 * The log function for para_server and para_audiod.
406 * \param ll The log level.
407 * \param fmt The format string describing the log message.
409 __printf_2_3 void daemon_log(int ll, const char* fmt,...)
415 bool log_time = daemon_test_flag(DF_LOG_TIME), log_timing =
416 daemon_test_flag(DF_LOG_TIMING);
418 ll = PARA_MIN(ll, NUM_LOGLEVELS - 1);
419 ll = PARA_MAX(ll, LL_DEBUG);
420 if (ll < me->loglevel)
423 fp = me->logfile? me->logfile : stderr;
424 if (me->pre_log_hook)
426 color = daemon_test_flag(DF_COLOR_LOG)? me->log_colors[ll] : NULL;
428 fprintf(fp, "%s", color);
429 if (log_time || log_timing) {
431 clock_get_realtime(&tv);
432 if (daemon_test_flag(DF_LOG_TIME)) { /* print date and time */
433 time_t t1 = tv.tv_sec;
436 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
437 fprintf(fp, "%s%s", str, log_timing? ":" : " ");
439 if (log_timing) /* print milliseconds */
440 fprintf(fp, "%04lu ", (long unsigned)tv.tv_usec / 1000);
442 if (daemon_test_flag(DF_LOG_HOSTNAME)) {
444 me->hostname = para_hostname();
445 fprintf(fp, "%s ", me->hostname);
447 if (daemon_test_flag(DF_LOG_LL)) /* log loglevel */
448 fprintf(fp, "(%d) ", ll);
449 if (daemon_test_flag(DF_LOG_PID)) { /* log pid */
450 pid_t mypid = getpid();
451 fprintf(fp, "(%d) ", (int)mypid);
454 vfprintf(fp, fmt, argp);
457 fprintf(fp, "%s", COLOR_RESET);
458 if (me->post_log_hook)