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