Introduce para_regcomp.
[paraslash.git] / daemon.c
1 /*
2 * Copyright (C) 1997-2009 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
14 #include "para.h"
15 #include "daemon.h"
16 #include "string.h"
17 #include "color.h"
18
19 /** The internal state of the daemon. */
20 struct daemon {
21 /** See \ref daemon_flags. */
22 unsigned flags;
23 /** Set by \ref daemon_set_logfile(). */
24 char *logfile_name;
25 /** Current loglevel, see \ref daemon_set_loglevel(). */
26 int loglevel;
27
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 /**
41 * Activate default log colors.
42 *
43 * This should be called early if color support is wanted.
44 */
45 void daemon_set_default_log_colors(void)
46 {
47 int i;
48 static const char *default_log_colors[NUM_LOGLEVELS] = {
49 [LL_DEBUG] = "normal",
50 [LL_INFO] = "normal",
51 [LL_NOTICE] = "normal",
52 [LL_WARNING] = "yellow",
53 [LL_ERROR] = "red",
54 [LL_CRIT] = "magenta bold",
55 [LL_EMERG] = "red bold",
56 };
57 for (i = 0; i < NUM_LOGLEVELS; i++) {
58 int ret = color_parse(default_log_colors[i], me->log_colors[i]);
59 assert(ret >= 0);
60 }
61 }
62
63 /**
64 * Set the color for one loglevel.
65 *
66 * \param arg The loglevel/color specifier.
67 *
68 * \a arg must be of the form "ll:[fg [bg]] [attr]".
69 *
70 * \return 1 On success, -1 on errors.
71 */
72 int daemon_set_log_color(char const *arg)
73 {
74 char *p = strchr(arg, ':');
75 int ret, ll;
76
77 if (!p)
78 goto err;
79 ret = get_loglevel_by_name(arg);
80 if (ret < 0)
81 goto err;
82 ll = ret;
83 p++;
84 ret = color_parse(p, me->log_colors[ll]);
85 if (ret < 0)
86 goto err;
87 return 1;
88 err:
89 PARA_ERROR_LOG("%s: color syntax error\n", arg);
90 return -1;
91
92 }
93
94 /**
95 * Init or change the name of the log file.
96 *
97 * \param logfile_name The full path of the logfile.
98 */
99 void daemon_set_logfile(char *logfile_name)
100 {
101 free(me->logfile_name);
102 me->logfile_name = NULL;
103 if (logfile_name)
104 me->logfile_name = para_strdup(logfile_name);
105 }
106
107 /**
108 * Supress log messages with severity lower than the given loglevel.
109 *
110 * \param loglevel The smallest level that should be logged.
111 */
112 void daemon_set_loglevel(char *loglevel)
113 {
114 int ret = get_loglevel_by_name(loglevel);
115
116 assert(ret >= 0);
117 me->loglevel = ret;
118 }
119
120 /**
121 * Set one of the daemon config flags.
122 *
123 * \param flag The flag to set.
124 *
125 * \sa \ref daemon_flags.
126 */
127 void daemon_set_flag(unsigned flag)
128 {
129 me->flags |= flag;
130 }
131
132 /**
133 * Clear one of the daemon config flags.
134 *
135 * \param flag The flag to clear.
136 *
137 * \sa \ref daemon_flags.
138 */
139 void daemon_clear_flag(unsigned flag)
140 {
141 me->flags &= ~flag;
142 }
143
144 static unsigned daemon_test_flag(unsigned flag)
145 {
146 return me->flags & flag;
147 }
148
149 /**
150 * Do the usual stuff to become a daemon.
151 *
152 * Fork, become session leader, dup fd 0, 1, 2 to /dev/null.
153 *
154 * \sa fork(2), setsid(2), dup(2).
155 */
156 void daemonize(void)
157 {
158 pid_t pid;
159 int null;
160
161 PARA_INFO_LOG("daemonizing\n");
162 pid = fork();
163 if (pid < 0)
164 goto err;
165 if (pid)
166 exit(EXIT_SUCCESS); /* parent exits */
167 /* become session leader */
168 if (setsid() < 0)
169 goto err;
170 if (chdir("/") < 0)
171 goto err;
172 umask(0);
173 null = open("/dev/null", O_RDONLY);
174 if (null < 0)
175 goto err;
176 if (dup2(null, STDIN_FILENO) < 0)
177 goto err;
178 if (dup2(null, STDOUT_FILENO) < 0)
179 goto err;
180 if (dup2(null, STDERR_FILENO) < 0)
181 goto err;
182 close(null);
183 return;
184 err:
185 PARA_EMERG_LOG("fatal: %s\n", strerror(errno));
186 exit(EXIT_FAILURE);
187 }
188
189 /**
190 * Close the log file of the daemon.
191 */
192 void daemon_close_log(void)
193 {
194 if (!me->logfile)
195 return;
196 PARA_INFO_LOG("closing logfile\n");
197 fclose(me->logfile);
198 me->logfile = NULL;
199 }
200
201 /**
202 * fopen() the logfile in append mode.
203 *
204 * \return Either succeeds or exits.
205 */
206 void daemon_open_log_or_die(void)
207 {
208 daemon_close_log();
209 if (!me->logfile_name)
210 return;
211 me->logfile = fopen(me->logfile_name, "a");
212 if (!me->logfile) {
213 PARA_EMERG_LOG("can not open %s: %s\n", me->logfile_name,
214 strerror(errno));
215 exit(EXIT_FAILURE);
216 }
217 setlinebuf(me->logfile);
218 }
219
220 /**
221 * Log the startup message containing the paraslash version.
222 */
223 void log_welcome(const char *whoami)
224 {
225 PARA_INFO_LOG("welcome to %s " PACKAGE_VERSION " ("BUILD_DATE")\n",
226 whoami);
227 }
228
229 /**
230 * Give up superuser privileges.
231 *
232 * \param username The user to switch to.
233 * \param groupname The group to switch to.
234 *
235 * This function returns immediately if not invoked with EUID zero. Otherwise,
236 * it tries to obtain the GID of \a groupname and the UID of \a username. On
237 * success, effective and real GID/UID and the saved set-group-ID/set-user-ID
238 * are all set accordingly. On errors, an appropriate message is logged and
239 * exit() is called to terminate the process.
240 *
241 * \sa getpwnam(3), getuid(2), setuid(2), getgrnam(2), setgid(2)
242 */
243 void drop_privileges_or_die(const char *username, const char *groupname)
244 {
245 struct passwd *p;
246 char *tmp;
247
248 if (geteuid())
249 return;
250 if (groupname) {
251 struct group *g = getgrnam(groupname);
252 if (!g) {
253 PARA_EMERG_LOG("failed to get group %s: %s\n",
254 groupname, strerror(errno));
255 exit(EXIT_FAILURE);
256 }
257 if (setgid(g->gr_gid) < 0) {
258 PARA_EMERG_LOG("failed to set group id %d: %s\n",
259 (int)g->gr_gid, strerror(errno));
260 exit(EXIT_FAILURE);
261 }
262 }
263 if (!username) {
264 PARA_EMERG_LOG("root privileges, but no user option given\n");
265 exit(EXIT_FAILURE);
266 }
267 tmp = para_strdup(username);
268 p = getpwnam(tmp);
269 free(tmp);
270 if (!p) {
271 PARA_EMERG_LOG("%s: no such user\n", username);
272 exit(EXIT_FAILURE);
273 }
274 PARA_INFO_LOG("dropping root privileges\n");
275 setuid(p->pw_uid);
276 PARA_DEBUG_LOG("uid: %d, euid: %d\n", (int)getuid(), (int)geteuid());
277 }
278
279 /**
280 * Set/get the server uptime.
281 *
282 * \param set_or_get Chose one of the two modes.
283 *
284 * This should be called at startup time with \a set_or_get equal to \p
285 * UPTIME_SET which sets the uptime to zero. Subsequent calls with \a
286 * set_or_get equal to \p UPTIME_GET return the uptime.
287
288 * \return Zero if called with \a set_or_get equal to \p UPTIME_SET, the number
289 * of seconds ellapsed since the last reset otherwise.
290 *
291 * \sa time(2), difftime(3).
292 */
293 time_t server_uptime(enum uptime set_or_get)
294 {
295 time_t now;
296 double diff;
297
298 if (set_or_get == UPTIME_SET) {
299 time(&me->startuptime);
300 return 0;
301 }
302 time(&now);
303 diff = difftime(now, me->startuptime);
304 return (time_t) diff;
305 }
306
307 /**
308 * Construct string containing uptime.
309 *
310 * \return A dynamically allocated string of the form "days:hours:minutes".
311 *
312 * \sa server_uptime.
313 */
314 __malloc char *uptime_str(void)
315 {
316 long t = server_uptime(UPTIME_GET);
317 return make_message("%li:%02li:%02li", t / 86400,
318 (t / 3600) % 24, (t / 60) % 60);
319 }
320
321 /**
322 * The log function for para_server and para_audiod.
323 *
324 * \param ll The log level.
325 * \param fmt The format string describing the log message.
326 */
327 __printf_2_3 void para_log(int ll, const char* fmt,...)
328 {
329 va_list argp;
330 FILE *fp;
331 struct tm *tm;
332 time_t t1;
333 char *color, str[MAXLINE] = "";
334
335 ll = PARA_MIN(ll, NUM_LOGLEVELS - 1);
336 ll = PARA_MAX(ll, LL_DEBUG);
337 if (ll < me->loglevel)
338 return;
339
340 fp = me->logfile? me->logfile : stderr;
341 color = daemon_test_flag(DF_COLOR_LOG)? me->log_colors[ll] : NULL;
342 if (color)
343 fprintf(fp, "%s", color);
344 if (daemon_test_flag(DF_LOG_TIME)) {
345 /* date and time */
346 time(&t1);
347 tm = localtime(&t1);
348 strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
349 fprintf(fp, "%s ", str);
350 }
351 if (daemon_test_flag(DF_LOG_HOSTNAME)) {
352 if (!me->hostname)
353 me->hostname = para_hostname();
354 fprintf(fp, "%s ", me->hostname);
355 }
356 if (daemon_test_flag(DF_LOG_LL)) /* log loglevel */
357 fprintf(fp, "(%d) ", ll);
358 if (daemon_test_flag(DF_LOG_PID)) { /* log pid */
359 pid_t mypid = getpid();
360 fprintf(fp, "(%d) ", (int)mypid);
361 }
362 va_start(argp, fmt);
363 vfprintf(fp, fmt, argp);
364 va_end(argp);
365 if (color)
366 fprintf(fp, "%s", COLOR_RESET);
367 }