Merge branch 'maint'
[paraslash.git] / daemon.c
1 /*
2 * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file daemon.c Some helpers for programs that detach from the console. */
8
9 #include <regex.h>
10 #include <pwd.h>
11 #include <sys/types.h> /* getgrnam() */
12 #include <grp.h>
13 #include <signal.h>
14
15 #include "para.h"
16 #include "daemon.h"
17 #include "string.h"
18 #include "color.h"
19
20 /** The internal state of the daemon. */
21 struct daemon {
22 /** See \ref daemon_flags. */
23 unsigned flags;
24 /** Set by \ref daemon_set_logfile(). */
25 char *logfile_name;
26 /** Current loglevel, see \ref daemon_set_loglevel(). */
27 int loglevel;
28 /** Used by \ref server_uptime() and \ref uptime_str(). */
29 time_t startuptime;
30 /** The file pointer if the logfile is open. */
31 FILE *logfile;
32 /** Used by para_log() if \p DF_LOG_HOSTNAME is set. */
33 char *hostname;
34 /** Used for colored log messages. */
35 char log_colors[NUM_LOGLEVELS][COLOR_MAXLEN];
36 };
37
38 static struct daemon the_daemon, *me = &the_daemon;
39
40 static void daemon_set_default_log_colors(void)
41 {
42 int i;
43 static const char *default_log_colors[NUM_LOGLEVELS] = {
44 [LL_DEBUG] = "normal",
45 [LL_INFO] = "normal",
46 [LL_NOTICE] = "normal",
47 [LL_WARNING] = "yellow",
48 [LL_ERROR] = "red",
49 [LL_CRIT] = "magenta bold",
50 [LL_EMERG] = "red bold",
51 };
52 for (i = 0; i < NUM_LOGLEVELS; i++)
53 color_parse_or_die(default_log_colors[i], me->log_colors[i]);
54 }
55
56 /*
57 * Set the color for one loglevel.
58 *
59 * arg must be of the form "ll:[fg [bg]] [attr]".
60 */
61 static void daemon_set_log_color_or_die(char const *arg)
62 {
63 char *p = strchr(arg, ':');
64 int ret, ll;
65
66 if (!p)
67 goto err;
68 ret = get_loglevel_by_name(arg);
69 if (ret < 0)
70 goto err;
71 ll = ret;
72 p++;
73 color_parse_or_die(p, me->log_colors[ll]);
74 return;
75 err:
76 PARA_EMERG_LOG("%s: color syntax error\n", arg);
77 exit(EXIT_FAILURE);
78 }
79
80 /**
81 * Initialize color mode if necessary.
82 *
83 * \param color_arg The argument given to --color.
84 * \param color_arg_auto The value for automatic color detection.
85 * \param color_arg_no The value to disable colored log messages.
86 * \param logfile_given In auto mode colors are disabled if this value is true.
87 * \param log_color_argv Color specifiers given to --log-color.
88 * \param argc Number of color specifiers in \a log_color_argv.
89 *
90 * If \a color_arg equals \a color_arg_no, color mode is disabled, i.e., calls
91 * to \a para_log() will not produce colored output. If \a color_arg == \a
92 * color_arg_auto, the function autodetects whether to activate colors.
93 * Otherwise color mode is enabled.
94 *
95 * If color mode is to be enabled, the strings in \a log_color_argv are parsed
96 * and the color scheme is updated accordingly. For each loglevel, the default
97 * colors apply if there is no log_color_argv for this loglevel.
98 */
99 void daemon_init_colors_or_die(int color_arg, int color_arg_auto,
100 int color_arg_no, bool logfile_given, char **log_color_argv,
101 int argc)
102 {
103 int i;
104
105 if (color_arg == color_arg_no)
106 return;
107 if (color_arg == color_arg_auto) {
108 if (logfile_given)
109 return;
110 if (!isatty(STDERR_FILENO))
111 return;
112 }
113 daemon_set_flag(DF_COLOR_LOG);
114 daemon_set_default_log_colors();
115 for (i = 0; i < argc; i++)
116 daemon_set_log_color_or_die(log_color_argv[i]);
117 }
118
119 /**
120 * Init or change the name of the log file.
121 *
122 * \param logfile_name The full path of the logfile.
123 */
124 void daemon_set_logfile(char *logfile_name)
125 {
126 free(me->logfile_name);
127 me->logfile_name = NULL;
128 if (logfile_name)
129 me->logfile_name = para_strdup(logfile_name);
130 }
131
132 /**
133 * Suppress log messages with severity lower than the given loglevel.
134 *
135 * \param loglevel The smallest level that should be logged.
136 */
137 void daemon_set_loglevel(char *loglevel)
138 {
139 int ret = get_loglevel_by_name(loglevel);
140
141 assert(ret >= 0);
142 me->loglevel = ret;
143 }
144
145 /**
146 * Set one of the daemon config flags.
147 *
148 * \param flag The flag to set.
149 *
150 * \sa \ref daemon_flags.
151 */
152 void daemon_set_flag(unsigned flag)
153 {
154 me->flags |= flag;
155 }
156
157 static bool daemon_test_flag(unsigned flag)
158 {
159 return me->flags & flag;
160 }
161
162 static void dummy_sighandler(__a_unused int s)
163 {
164 }
165
166 /**
167 * Do the usual stuff to become a daemon.
168 *
169 * \param parent_waits Whether the parent process should pause before exit.
170 *
171 * Fork, become session leader, cd to /, and dup fd 0, 1, 2 to /dev/null. If \a
172 * parent_waits is false, the parent process terminates immediately.
173 * Otherwise, it calls pause() to sleep until it receives \p SIGTERM or \p
174 * SIGCHLD and exits successfully thereafter. This behaviour is useful if the
175 * daemon process should not detach from the console until the child process
176 * has completed its setup.
177 *
178 * \sa fork(2), setsid(2), dup(2), pause(2).
179 */
180 void daemonize(bool parent_waits)
181 {
182 pid_t pid;
183 int null;
184
185 PARA_INFO_LOG("daemonizing\n");
186 pid = fork();
187 if (pid < 0)
188 goto err;
189 if (pid) {
190 if (parent_waits) {
191 signal(SIGTERM, dummy_sighandler);
192 signal(SIGCHLD, dummy_sighandler);
193 pause();
194 }
195 exit(EXIT_SUCCESS); /* parent exits */
196 }
197 /* become session leader */
198 if (setsid() < 0)
199 goto err;
200 if (chdir("/") < 0)
201 goto err;
202 null = open("/dev/null", O_RDWR);
203 if (null < 0)
204 goto err;
205 if (dup2(null, STDIN_FILENO) < 0)
206 goto err;
207 if (dup2(null, STDOUT_FILENO) < 0)
208 goto err;
209 if (dup2(null, STDERR_FILENO) < 0)
210 goto err;
211 close(null);
212 return;
213 err:
214 PARA_EMERG_LOG("fatal: %s\n", strerror(errno));
215 exit(EXIT_FAILURE);
216 }
217
218 /**
219 * Close the log file of the daemon.
220 */
221 void daemon_close_log(void)
222 {
223 if (!me->logfile)
224 return;
225 PARA_INFO_LOG("closing logfile\n");
226 fclose(me->logfile);
227 me->logfile = NULL;
228 }
229
230 /**
231 * fopen() the logfile in append mode.
232 *
233 * \return Either succeeds or exits.
234 */
235 void daemon_open_log_or_die(void)
236 {
237 daemon_close_log();
238 if (!me->logfile_name)
239 return;
240 me->logfile = fopen(me->logfile_name, "a");
241 if (!me->logfile) {
242 PARA_EMERG_LOG("can not open %s: %s\n", me->logfile_name,
243 strerror(errno));
244 exit(EXIT_FAILURE);
245 }
246 /* equivalent to setlinebuf(), but portable */
247 setvbuf(me->logfile, NULL, _IOLBF, 0);
248 }
249
250 /**
251 * Log the startup message containing the paraslash version.
252 */
253 void daemon_log_welcome(const char *whoami)
254 {
255 PARA_INFO_LOG("welcome to %s " PACKAGE_VERSION " ("BUILD_DATE")\n",
256 whoami);
257 }
258
259 /**
260 * Give up superuser privileges.
261 *
262 * \param username The user to switch to.
263 * \param groupname The group to switch to.
264 *
265 * This function returns immediately if not invoked with EUID zero. Otherwise,
266 * it tries to obtain the GID of \a groupname and the UID of \a username. On
267 * success, effective and real GID/UID and the saved set-group-ID/set-user-ID
268 * are all set accordingly. On errors, an appropriate message is logged and
269 * exit() is called to terminate the process.
270 *
271 * \sa getpwnam(3), getuid(2), setuid(2), getgrnam(2), setgid(2)
272 */
273 void daemon_drop_privileges_or_die(const char *username, const char *groupname)
274 {
275 struct passwd *p;
276 char *tmp;
277
278 if (geteuid())
279 return;
280 if (groupname) {
281 struct group *g = getgrnam(groupname);
282 if (!g) {
283 PARA_EMERG_LOG("failed to get group %s: %s\n",
284 groupname, strerror(errno));
285 exit(EXIT_FAILURE);
286 }
287 if (setgid(g->gr_gid) < 0) {
288 PARA_EMERG_LOG("failed to set group id %d: %s\n",
289 (int)g->gr_gid, strerror(errno));
290 exit(EXIT_FAILURE);
291 }
292 }
293 if (!username) {
294 PARA_EMERG_LOG("root privileges, but no user option given\n");
295 exit(EXIT_FAILURE);
296 }
297 tmp = para_strdup(username);
298 p = getpwnam(tmp);
299 free(tmp);
300 if (!p) {
301 PARA_EMERG_LOG("%s: no such user\n", username);
302 exit(EXIT_FAILURE);
303 }
304 PARA_INFO_LOG("dropping root privileges\n");
305 if (setuid(p->pw_uid) < 0) {
306 PARA_EMERG_LOG("failed to set effective user ID (%s)",
307 strerror(errno));
308 exit(EXIT_FAILURE);
309 }
310 PARA_DEBUG_LOG("uid: %d, euid: %d\n", (int)getuid(), (int)geteuid());
311 }
312
313 /**
314 * Set the startup time.
315 *
316 * This should be called once on startup. It sets the start time to the
317 * current time. The stored time is used for retrieving the server uptime.
318 *
319 * \sa time(2), \ref daemon_get_uptime(), \ref daemon_get_uptime_str().
320 */
321 void daemon_set_start_time(void)
322 {
323 time(&me->startuptime);
324 }
325
326 /**
327 * Get the uptime.
328 *
329 * \param current_time The current time.
330 *
331 * The \a current_time pointer may be \p NULL. In this case the function
332 * obtains the current time from the system.
333 *
334 * \return This returns the server uptime in seconds, i.e. the difference
335 * between the current time and the value stored previously via \ref
336 * daemon_set_start_time().
337 */
338 time_t daemon_get_uptime(const struct timeval *current_time)
339 {
340 time_t t;
341
342 if (current_time)
343 return current_time->tv_sec - me->startuptime;
344 time(&t);
345 return difftime(t, me->startuptime);
346 }
347
348 /**
349 * Construct a string containing the current uptime.
350 *
351 * \param current_time See a \ref daemon_get_uptime().
352 *
353 * \return A dynamically allocated string of the form "days:hours:minutes".
354 *
355 * \sa server_uptime.
356 */
357 __malloc char *daemon_get_uptime_str(const struct timeval *current_time)
358 {
359 long t = daemon_get_uptime(current_time);
360 return make_message("%li:%02li:%02li", t / 86400,
361 (t / 3600) % 24, (t / 60) % 60);
362 }
363
364 /**
365 * The log function for para_server and para_audiod.
366 *
367 * \param ll The log level.
368 * \param fmt The format string describing the log message.
369 */
370 __printf_2_3 void daemon_log(int ll, const char* fmt,...)
371 {
372 va_list argp;
373 FILE *fp;
374 struct tm *tm;
375 char *color;
376 bool log_time = daemon_test_flag(DF_LOG_TIME), log_timing =
377 daemon_test_flag(DF_LOG_TIMING);
378
379 ll = PARA_MIN(ll, NUM_LOGLEVELS - 1);
380 ll = PARA_MAX(ll, LL_DEBUG);
381 if (ll < me->loglevel)
382 return;
383
384 fp = me->logfile? me->logfile : stderr;
385 color = daemon_test_flag(DF_COLOR_LOG)? me->log_colors[ll] : NULL;
386 if (color)
387 fprintf(fp, "%s", color);
388 if (log_time || log_timing) {
389 struct timeval tv;
390 clock_get_realtime(&tv);
391 if (daemon_test_flag(DF_LOG_TIME)) { /* print date and time */
392 time_t t1 = tv.tv_sec;
393 char str[100];
394 tm = localtime(&t1);
395 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
396 fprintf(fp, "%s%s", str, log_timing? ":" : " ");
397 }
398 if (log_timing) /* print milliseconds */
399 fprintf(fp, "%04lu ", (long unsigned)tv.tv_usec / 1000);
400 }
401 if (daemon_test_flag(DF_LOG_HOSTNAME)) {
402 if (!me->hostname)
403 me->hostname = para_hostname();
404 fprintf(fp, "%s ", me->hostname);
405 }
406 if (daemon_test_flag(DF_LOG_LL)) /* log loglevel */
407 fprintf(fp, "(%d) ", ll);
408 if (daemon_test_flag(DF_LOG_PID)) { /* log pid */
409 pid_t mypid = getpid();
410 fprintf(fp, "(%d) ", (int)mypid);
411 }
412 va_start(argp, fmt);
413 vfprintf(fp, fmt, argp);
414 va_end(argp);
415 if (color)
416 fprintf(fp, "%s", COLOR_RESET);
417 }