Merge branch 't/map_populate'
[paraslash.git] / daemon.c
1 /*
2 * Copyright (C) 1997-2011 Andre Noll <maan@systemlinux.org>
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 <sys/time.h>
14 #include <stdbool.h>
15
16 #include "para.h"
17 #include "daemon.h"
18 #include "string.h"
19 #include "color.h"
20
21 /** The internal state of the daemon. */
22 struct daemon {
23 /** See \ref daemon_flags. */
24 unsigned flags;
25 /** Set by \ref daemon_set_logfile(). */
26 char *logfile_name;
27 /** Current loglevel, see \ref daemon_set_loglevel(). */
28 int loglevel;
29 /** Used by \ref server_uptime() and \ref uptime_str(). */
30 time_t startuptime;
31 /** The file pointer if the logfile is open. */
32 FILE *logfile;
33 /** Used by para_log() if \p DF_LOG_HOSTNAME is set. */
34 char *hostname;
35 /** Used for colored log messages. */
36 char log_colors[NUM_LOGLEVELS][COLOR_MAXLEN];
37 };
38
39 static struct daemon the_daemon, *me = &the_daemon;
40
41 /**
42 * Activate default log colors.
43 *
44 * This should be called early if color support is wanted.
45 */
46 void daemon_set_default_log_colors(void)
47 {
48 int i;
49 static const char *default_log_colors[NUM_LOGLEVELS] = {
50 [LL_DEBUG] = "normal",
51 [LL_INFO] = "normal",
52 [LL_NOTICE] = "normal",
53 [LL_WARNING] = "yellow",
54 [LL_ERROR] = "red",
55 [LL_CRIT] = "magenta bold",
56 [LL_EMERG] = "red bold",
57 };
58 for (i = 0; i < NUM_LOGLEVELS; i++)
59 color_parse_or_die(default_log_colors[i], me->log_colors[i]);
60 }
61
62 /**
63 * Set the color for one loglevel.
64 *
65 * \param arg The loglevel/color specifier.
66 *
67 * \a arg must be of the form "ll:[fg [bg]] [attr]".
68 *
69 * \return 1 On success, -1 on errors.
70 */
71 void daemon_set_log_color_or_die(char const *arg)
72 {
73 char *p = strchr(arg, ':');
74 int ret, ll;
75
76 if (!p)
77 goto err;
78 ret = get_loglevel_by_name(arg);
79 if (ret < 0)
80 goto err;
81 ll = ret;
82 p++;
83 color_parse_or_die(p, me->log_colors[ll]);
84 return;
85 err:
86 PARA_EMERG_LOG("%s: color syntax error\n", arg);
87 exit(EXIT_FAILURE);
88 }
89
90 /**
91 * Init or change the name of the log file.
92 *
93 * \param logfile_name The full path of the logfile.
94 */
95 void daemon_set_logfile(char *logfile_name)
96 {
97 free(me->logfile_name);
98 me->logfile_name = NULL;
99 if (logfile_name)
100 me->logfile_name = para_strdup(logfile_name);
101 }
102
103 /**
104 * Suppress log messages with severity lower than the given loglevel.
105 *
106 * \param loglevel The smallest level that should be logged.
107 */
108 void daemon_set_loglevel(char *loglevel)
109 {
110 int ret = get_loglevel_by_name(loglevel);
111
112 assert(ret >= 0);
113 me->loglevel = ret;
114 }
115
116 /**
117 * Set one of the daemon config flags.
118 *
119 * \param flag The flag to set.
120 *
121 * \sa \ref daemon_flags.
122 */
123 void daemon_set_flag(unsigned flag)
124 {
125 me->flags |= flag;
126 }
127
128 /**
129 * Clear one of the daemon config flags.
130 *
131 * \param flag The flag to clear.
132 *
133 * \sa \ref daemon_flags.
134 */
135 void daemon_clear_flag(unsigned flag)
136 {
137 me->flags &= ~flag;
138 }
139
140 static bool daemon_test_flag(unsigned flag)
141 {
142 return me->flags & flag;
143 }
144
145 /**
146 * Do the usual stuff to become a daemon.
147 *
148 * Fork, become session leader, dup fd 0, 1, 2 to /dev/null.
149 *
150 * \sa fork(2), setsid(2), dup(2).
151 */
152 void daemonize(void)
153 {
154 pid_t pid;
155 int null;
156
157 PARA_INFO_LOG("daemonizing\n");
158 pid = fork();
159 if (pid < 0)
160 goto err;
161 if (pid)
162 exit(EXIT_SUCCESS); /* parent exits */
163 /* become session leader */
164 if (setsid() < 0)
165 goto err;
166 if (chdir("/") < 0)
167 goto err;
168 null = open("/dev/null", O_RDONLY);
169 if (null < 0)
170 goto err;
171 if (dup2(null, STDIN_FILENO) < 0)
172 goto err;
173 if (dup2(null, STDOUT_FILENO) < 0)
174 goto err;
175 if (dup2(null, STDERR_FILENO) < 0)
176 goto err;
177 close(null);
178 return;
179 err:
180 PARA_EMERG_LOG("fatal: %s\n", strerror(errno));
181 exit(EXIT_FAILURE);
182 }
183
184 /**
185 * Close the log file of the daemon.
186 */
187 void daemon_close_log(void)
188 {
189 if (!me->logfile)
190 return;
191 PARA_INFO_LOG("closing logfile\n");
192 fclose(me->logfile);
193 me->logfile = NULL;
194 }
195
196 /**
197 * fopen() the logfile in append mode.
198 *
199 * \return Either succeeds or exits.
200 */
201 void daemon_open_log_or_die(void)
202 {
203 daemon_close_log();
204 if (!me->logfile_name)
205 return;
206 me->logfile = fopen(me->logfile_name, "a");
207 if (!me->logfile) {
208 PARA_EMERG_LOG("can not open %s: %s\n", me->logfile_name,
209 strerror(errno));
210 exit(EXIT_FAILURE);
211 }
212 setlinebuf(me->logfile);
213 }
214
215 /**
216 * Log the startup message containing the paraslash version.
217 */
218 void log_welcome(const char *whoami)
219 {
220 PARA_INFO_LOG("welcome to %s " PACKAGE_VERSION " ("BUILD_DATE")\n",
221 whoami);
222 }
223
224 /**
225 * Give up superuser privileges.
226 *
227 * \param username The user to switch to.
228 * \param groupname The group to switch to.
229 *
230 * This function returns immediately if not invoked with EUID zero. Otherwise,
231 * it tries to obtain the GID of \a groupname and the UID of \a username. On
232 * success, effective and real GID/UID and the saved set-group-ID/set-user-ID
233 * are all set accordingly. On errors, an appropriate message is logged and
234 * exit() is called to terminate the process.
235 *
236 * \sa getpwnam(3), getuid(2), setuid(2), getgrnam(2), setgid(2)
237 */
238 void drop_privileges_or_die(const char *username, const char *groupname)
239 {
240 struct passwd *p;
241 char *tmp;
242
243 if (geteuid())
244 return;
245 if (groupname) {
246 struct group *g = getgrnam(groupname);
247 if (!g) {
248 PARA_EMERG_LOG("failed to get group %s: %s\n",
249 groupname, strerror(errno));
250 exit(EXIT_FAILURE);
251 }
252 if (setgid(g->gr_gid) < 0) {
253 PARA_EMERG_LOG("failed to set group id %d: %s\n",
254 (int)g->gr_gid, strerror(errno));
255 exit(EXIT_FAILURE);
256 }
257 }
258 if (!username) {
259 PARA_EMERG_LOG("root privileges, but no user option given\n");
260 exit(EXIT_FAILURE);
261 }
262 tmp = para_strdup(username);
263 p = getpwnam(tmp);
264 free(tmp);
265 if (!p) {
266 PARA_EMERG_LOG("%s: no such user\n", username);
267 exit(EXIT_FAILURE);
268 }
269 PARA_INFO_LOG("dropping root privileges\n");
270 if (setuid(p->pw_uid) < 0) {
271 PARA_EMERG_LOG("failed to set effective user ID (%s)",
272 strerror(errno));
273 exit(EXIT_FAILURE);
274 }
275 PARA_DEBUG_LOG("uid: %d, euid: %d\n", (int)getuid(), (int)geteuid());
276 }
277
278 /**
279 * Set the server startup time.
280 *
281 * \param startuptime The value to store as the server start time.
282 *
283 * This should be called once on startup with \a startuptime either NULL or a
284 * pointer to a struct timeval which contains the current time. If \a
285 * startuptime is NULL, the server start time is set to the current time.
286 *
287 * \sa time(2), difftime(3) \ref get_server_uptime(), \ref
288 * get_server_uptime_str().
289 */
290 void set_server_start_time(const struct timeval *startuptime)
291 {
292 if (startuptime)
293 me->startuptime = startuptime->tv_sec;
294 else
295 time(&me->startuptime);
296 }
297
298 /**
299 * Get the server uptime.
300 *
301 * \param current_time The current time.
302 *
303 * The \a current_time pointer may be \p NULL. In this case the function
304 * obtains the current time from the system.
305 *
306 * \return This returns the server uptime in seconds, i.e. the difference
307 * between the current time and the value stored previously via \ref
308 * set_server_start_time().
309 */
310 time_t get_server_uptime(const struct timeval *current_time)
311 {
312 time_t t;
313
314 if (current_time)
315 return current_time->tv_sec - me->startuptime;
316 time(&t);
317 return difftime(t, me->startuptime);
318 }
319
320 /**
321 * Construct a string containing the current uptime.
322 *
323 * \param current_time See a \ref get_server_uptime().
324 *
325 * \return A dynamically allocated string of the form "days:hours:minutes".
326 *
327 * \sa server_uptime.
328 */
329 __malloc char *get_server_uptime_str(const struct timeval *current_time)
330 {
331 long t = get_server_uptime(current_time);
332 return make_message("%li:%02li:%02li", t / 86400,
333 (t / 3600) % 24, (t / 60) % 60);
334 }
335
336 /**
337 * The log function for para_server and para_audiod.
338 *
339 * \param ll The log level.
340 * \param fmt The format string describing the log message.
341 */
342 __printf_2_3 void para_log(int ll, const char* fmt,...)
343 {
344 va_list argp;
345 FILE *fp;
346 struct tm *tm;
347 char *color;
348 bool log_time = daemon_test_flag(DF_LOG_TIME), log_timing =
349 daemon_test_flag(DF_LOG_TIMING);
350
351 ll = PARA_MIN(ll, NUM_LOGLEVELS - 1);
352 ll = PARA_MAX(ll, LL_DEBUG);
353 if (ll < me->loglevel)
354 return;
355
356 fp = me->logfile? me->logfile : stderr;
357 color = daemon_test_flag(DF_COLOR_LOG)? me->log_colors[ll] : NULL;
358 if (color)
359 fprintf(fp, "%s", color);
360 if (log_time || log_timing) {
361 struct timeval tv;
362 gettimeofday(&tv, NULL);
363 if (daemon_test_flag(DF_LOG_TIME)) { /* print date and time */
364 time_t t1 = tv.tv_sec;
365 char str[100];
366 tm = localtime(&t1);
367 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
368 fprintf(fp, "%s%s", str, log_timing? ":" : " ");
369 }
370 if (log_timing) /* print milliseconds */
371 fprintf(fp, "%04lu ", (long unsigned)tv.tv_usec / 1000);
372 }
373 if (daemon_test_flag(DF_LOG_HOSTNAME)) {
374 if (!me->hostname)
375 me->hostname = para_hostname();
376 fprintf(fp, "%s ", me->hostname);
377 }
378 if (daemon_test_flag(DF_LOG_LL)) /* log loglevel */
379 fprintf(fp, "(%d) ", ll);
380 if (daemon_test_flag(DF_LOG_PID)) { /* log pid */
381 pid_t mypid = getpid();
382 fprintf(fp, "(%d) ", (int)mypid);
383 }
384 va_start(argp, fmt);
385 vfprintf(fp, fmt, argp);
386 va_end(argp);
387 if (color)
388 fprintf(fp, "%s", COLOR_RESET);
389 }