1 /* vi: set sw=4 ts=4: */
3 * Mini syslogd implementation for busybox
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
7 * Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
9 * "circular buffer" Copyright (C) 2001 by Gennady Feldman <gfeldman@gena01.com>
11 * Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
13 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
18 #define SYSLOG_NAMES_CONST
25 #if ENABLE_FEATURE_REMOTE_LOG
26 #include <netinet/in.h>
29 #if ENABLE_FEATURE_IPC_SYSLOG
38 /* MARK code is not very useful, is bloat, and broken:
39 * can deadlock if alarmed to make MARK while writing to IPC buffer
40 * (semaphores are down but do_mark routine tries to down them again) */
45 DNS_WAIT_SEC = 2 * 60,
48 /* Semaphore operation structures */
50 int32_t size; /* size of data - 1 */
51 int32_t tail; /* end of message list */
52 char data[1]; /* data/messages */
55 /* Allows us to have smaller initializer. Ugly. */
57 const char *logFilePath; \
59 /* interval between marks in seconds */ \
60 /*int markInterval;*/ \
61 /* level of messages to be logged */ \
63 USE_FEATURE_ROTATE_LOGFILE( \
64 /* max size of file before rotation */ \
65 unsigned logFileSize; \
66 /* number of rotated message files */ \
67 unsigned logFileRotate; \
68 unsigned curFileSize; \
71 USE_FEATURE_REMOTE_LOG( \
72 /* udp socket for remote logging */ \
74 len_and_sockaddr* remoteAddr; \
76 USE_FEATURE_IPC_SYSLOG( \
77 int shmid; /* ipc shared memory id */ \
78 int s_semid; /* ipc semaphore id */ \
80 struct sembuf SMwup[1]; \
81 struct sembuf SMwdn[3]; \
91 #if ENABLE_FEATURE_REMOTE_LOG
92 unsigned last_dns_resolve;
96 #if ENABLE_FEATURE_IPC_SYSLOG
97 struct shbuf_ds *shbuf;
100 /* localhost's name. We print only first 64 chars */
103 /* We recv into recvbuf... */
104 char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
105 /* ...then copy to parsebuf, escaping control chars */
106 /* (can grow x2 max) */
107 char parsebuf[MAX_READ*2];
108 /* ...then sprintf into printbuf, adding timestamp (15 chars),
109 * host (64), fac.prio (20) to the message */
110 /* (growth by: 15 + 64 + 20 + delims = ~110) */
111 char printbuf[MAX_READ*2 + 128];
114 static const struct init_globals init_data = {
115 .logFilePath = "/var/log/messages",
118 .markInterval = 20 * 60,
121 #if ENABLE_FEATURE_ROTATE_LOGFILE
122 .logFileSize = 200 * 1024,
125 #if ENABLE_FEATURE_REMOTE_LOG
128 #if ENABLE_FEATURE_IPC_SYSLOG
131 .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), // default shm size
132 .SMwup = { {1, -1, IPC_NOWAIT} },
133 .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
137 #define G (*ptr_to_globals)
138 #define INIT_G() do { \
139 SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
145 OPTBIT_mark = 0, // -m
147 OPTBIT_outfile, // -O
148 OPTBIT_loglevel, // -l
150 USE_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize ,) // -s
151 USE_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt ,) // -b
152 USE_FEATURE_REMOTE_LOG( OPTBIT_remote ,) // -R
153 USE_FEATURE_REMOTE_LOG( OPTBIT_locallog ,) // -L
154 USE_FEATURE_IPC_SYSLOG( OPTBIT_circularlog,) // -C
155 USE_FEATURE_SYSLOGD_DUP( OPTBIT_dup ,) // -D
157 OPT_mark = 1 << OPTBIT_mark ,
158 OPT_nofork = 1 << OPTBIT_nofork ,
159 OPT_outfile = 1 << OPTBIT_outfile ,
160 OPT_loglevel = 1 << OPTBIT_loglevel,
161 OPT_small = 1 << OPTBIT_small ,
162 OPT_filesize = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize )) + 0,
163 OPT_rotatecnt = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt )) + 0,
164 OPT_remotelog = USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_remote )) + 0,
165 OPT_locallog = USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_locallog )) + 0,
166 OPT_circularlog = USE_FEATURE_IPC_SYSLOG( (1 << OPTBIT_circularlog)) + 0,
167 OPT_dup = USE_FEATURE_SYSLOGD_DUP( (1 << OPTBIT_dup )) + 0,
169 #define OPTION_STR "m:nO:l:S" \
170 USE_FEATURE_ROTATE_LOGFILE("s:" ) \
171 USE_FEATURE_ROTATE_LOGFILE("b:" ) \
172 USE_FEATURE_REMOTE_LOG( "R:" ) \
173 USE_FEATURE_REMOTE_LOG( "L" ) \
174 USE_FEATURE_IPC_SYSLOG( "C::") \
175 USE_FEATURE_SYSLOGD_DUP( "D" )
176 #define OPTION_DECL *opt_m, *opt_l \
177 USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
178 USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
179 USE_FEATURE_IPC_SYSLOG( ,*opt_C = NULL)
180 #define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \
181 USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
182 USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
183 USE_FEATURE_REMOTE_LOG( ,&G.remoteAddrStr) \
184 USE_FEATURE_IPC_SYSLOG( ,&opt_C)
187 /* circular buffer variables/structures */
188 #if ENABLE_FEATURE_IPC_SYSLOG
190 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
191 #error Sorry, you must set the syslogd buffer size to at least 4KB.
192 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
196 #define KEY_ID ((long)0x414e4547) /* "GENA" */
198 static void ipcsyslog_cleanup(void)
204 shmctl(G.shmid, IPC_RMID, NULL);
206 if (G.s_semid != -1) {
207 semctl(G.s_semid, 0, IPC_RMID, 0);
211 static void ipcsyslog_init(void)
214 printf("shmget(%lx, %d,...)\n", KEY_ID, G.shm_size);
216 G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
218 bb_perror_msg_and_die("shmget");
221 G.shbuf = shmat(G.shmid, NULL, 0);
222 if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
223 bb_perror_msg_and_die("shmat");
226 memset(G.shbuf, 0, G.shm_size);
227 G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
228 /*G.shbuf->tail = 0;*/
230 // we'll trust the OS to set initial semval to 0 (let's hope)
231 G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
232 if (G.s_semid == -1) {
233 if (errno == EEXIST) {
234 G.s_semid = semget(KEY_ID, 2, 0);
238 bb_perror_msg_and_die("semget");
242 /* Write message to shared mem buffer */
243 static void log_to_shmem(const char *msg, int len)
245 int old_tail, new_tail;
247 if (semop(G.s_semid, G.SMwdn, 3) == -1) {
248 bb_perror_msg_and_die("SMwdn");
251 /* Circular Buffer Algorithm:
252 * --------------------------
253 * tail == position where to store next syslog message.
254 * tail's max value is (shbuf->size - 1)
255 * Last byte of buffer is never used and remains NUL.
257 len++; /* length with NUL included */
259 old_tail = G.shbuf->tail;
260 new_tail = old_tail + len;
261 if (new_tail < G.shbuf->size) {
262 /* store message, set new tail */
263 memcpy(G.shbuf->data + old_tail, msg, len);
264 G.shbuf->tail = new_tail;
266 /* k == available buffer space ahead of old tail */
267 int k = G.shbuf->size - old_tail;
268 /* copy what fits to the end of buffer, and repeat */
269 memcpy(G.shbuf->data + old_tail, msg, k);
275 if (semop(G.s_semid, G.SMwup, 1) == -1) {
276 bb_perror_msg_and_die("SMwup");
279 printf("tail:%d\n", G.shbuf->tail);
282 void ipcsyslog_cleanup(void);
283 void ipcsyslog_init(void);
284 void log_to_shmem(const char *msg);
285 #endif /* FEATURE_IPC_SYSLOG */
288 /* Print a message to the log file. */
289 static void log_locally(time_t now, char *msg)
292 int len = strlen(msg);
294 #if ENABLE_FEATURE_IPC_SYSLOG
295 if ((option_mask32 & OPT_circularlog) && G.shbuf) {
296 log_to_shmem(msg, len);
303 if (G.last_log_time != now) {
304 G.last_log_time = now; /* reopen log file every second */
310 G.logFD = device_open(G.logFilePath, O_WRONLY | O_CREAT
311 | O_NOCTTY | O_APPEND | O_NONBLOCK);
313 /* cannot open logfile? - print to /dev/console then */
314 int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
316 fd = 2; /* then stderr, dammit */
317 full_write(fd, msg, len);
322 #if ENABLE_FEATURE_ROTATE_LOGFILE
325 G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode));
326 /* bug (mostly harmless): can wrap around if file > 4gb */
327 G.curFileSize = statf.st_size;
332 fl.l_whence = SEEK_SET;
336 fcntl(G.logFD, F_SETLKW, &fl);
338 #if ENABLE_FEATURE_ROTATE_LOGFILE
339 if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) {
340 if (G.logFileRotate) { /* always 0..99 */
341 int i = strlen(G.logFilePath) + 3 + 1;
344 i = G.logFileRotate - 1;
345 /* rename: f.8 -> f.9; f.7 -> f.8; ... */
347 sprintf(newFile, "%s.%d", G.logFilePath, i);
349 sprintf(oldFile, "%s.%d", G.logFilePath, --i);
350 /* ignore errors - file might be missing */
351 rename(oldFile, newFile);
353 /* newFile == "f.0" now */
354 rename(G.logFilePath, newFile);
356 fcntl(G.logFD, F_SETLKW, &fl);
360 ftruncate(G.logFD, 0);
364 full_write(G.logFD, msg, len);
366 fcntl(G.logFD, F_SETLKW, &fl);
369 static void parse_fac_prio_20(int pri, char *res20)
371 const CODE *c_pri, *c_fac;
374 c_fac = facilitynames;
375 while (c_fac->c_name) {
376 if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
380 /* facility is found, look for prio */
381 c_pri = prioritynames;
382 while (c_pri->c_name) {
383 if (c_pri->c_val != LOG_PRI(pri)) {
387 snprintf(res20, 20, "%s.%s",
388 c_fac->c_name, c_pri->c_name);
391 /* prio not found, bail out */
394 snprintf(res20, 20, "<%d>", pri);
398 /* len parameter is used only for "is there a timestamp?" check.
399 * NB: some callers cheat and supply len==0 when they know
400 * that there is no timestamp, short-circuiting the test. */
401 static void timestamp_and_log(int pri, char *msg, int len)
406 if (len < 16 || msg[3] != ' ' || msg[6] != ' '
407 || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
410 timestamp = ctime(&now) + 4; /* skip day of week */
416 timestamp[15] = '\0';
418 if (option_mask32 & OPT_small)
419 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
422 parse_fac_prio_20(pri, res);
423 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
426 /* Log message locally (to file or shared mem) */
427 log_locally(now, G.printbuf);
430 static void timestamp_and_log_internal(const char *msg)
432 if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
434 timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
437 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
438 * embedded NULs. Split messages on each of these NULs, parse prio,
439 * escape control chars and log each locally. */
440 static void split_escape_and_log(char *tmpbuf, int len)
447 char *q = G.parsebuf;
448 int pri = (LOG_USER | LOG_NOTICE);
451 /* Parse the magic priority number */
452 pri = bb_strtou(p + 1, &p, 10);
455 if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
456 pri = (LOG_USER | LOG_NOTICE);
462 if (!(c & ~0x1f) && c != '\t') {
464 c += '@'; /* ^@, ^A, ^B... */
471 if (LOG_PRI(pri) < G.logLevel)
472 timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
476 static void quit_signal(int sig)
478 timestamp_and_log_internal("syslogd exiting");
479 puts("syslogd exiting");
480 if (ENABLE_FEATURE_IPC_SYSLOG)
482 kill_myself_with_sig(sig);
486 static void do_mark(int sig)
488 if (G.markInterval) {
489 timestamp_and_log_internal("-- MARK --");
490 alarm(G.markInterval);
495 /* Don't inline: prevent struct sockaddr_un to take up space on stack
497 static NOINLINE int create_socket(void)
499 struct sockaddr_un sunx;
503 memset(&sunx, 0, sizeof(sunx));
504 sunx.sun_family = AF_UNIX;
506 /* Unlink old /dev/log or object it points to. */
507 /* (if it exists, bind will fail) */
508 strcpy(sunx.sun_path, "/dev/log");
509 dev_log_name = xmalloc_follow_symlinks("/dev/log");
511 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
514 unlink(sunx.sun_path);
516 sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
517 xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
518 chmod("/dev/log", 0666);
523 #if ENABLE_FEATURE_REMOTE_LOG
524 static int try_to_resolve_remote(void)
527 unsigned now = monotonic_sec();
529 /* Don't resolve name too often - DNS timeouts can be big */
530 if ((now - G.last_dns_resolve) < DNS_WAIT_SEC)
532 G.last_dns_resolve = now;
533 G.remoteAddr = host2sockaddr(G.remoteAddrStr, 514);
537 return socket(G.remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
541 static void do_syslogd(void) ATTRIBUTE_NORETURN;
542 static void do_syslogd(void)
545 #if ENABLE_FEATURE_SYSLOGD_DUP
548 char *recvbuf = G.recvbuf;
550 #define recvbuf (G.recvbuf)
553 /* Set up signal handlers */
559 signal(SIGHUP, SIG_IGN);
560 /* signal(SIGCHLD, SIG_IGN); - why? */
562 signal(SIGALRM, do_mark);
563 alarm(G.markInterval);
565 sock_fd = create_socket();
567 if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
571 timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
576 #if ENABLE_FEATURE_SYSLOGD_DUP
578 if (recvbuf == G.recvbuf)
579 recvbuf = G.recvbuf + MAX_READ;
584 sz = safe_read(sock_fd, recvbuf, MAX_READ - 1);
586 bb_perror_msg_and_die("read from /dev/log");
588 /* Drop trailing '\n' and NULs (typically there is one NUL) */
592 /* man 3 syslog says: "A trailing newline is added when needed".
593 * However, neither glibc nor uclibc do this:
594 * syslog(prio, "test") sends "test\0" to /dev/log,
595 * syslog(prio, "test\n") sends "test\n\0".
596 * IOW: newline is passed verbatim!
597 * I take it to mean that it's syslogd's job
598 * to make those look identical in the log files. */
599 if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
603 #if ENABLE_FEATURE_SYSLOGD_DUP
604 if ((option_mask32 & OPT_dup) && (sz == last_sz))
605 if (memcmp(last_buf, recvbuf, sz) == 0)
609 #if ENABLE_FEATURE_REMOTE_LOG
610 /* We are not modifying log messages in any way before send */
611 /* Remote site cannot trust _us_ anyway and need to do validation again */
612 if (G.remoteAddrStr) {
613 if (-1 == G.remoteFD) {
614 G.remoteFD = try_to_resolve_remote();
615 if (-1 == G.remoteFD)
618 /* Stock syslogd sends it '\n'-terminated
619 * over network, mimic that */
621 /* send message to remote logger, ignore possible error */
622 /* TODO: on some errors, close and set G.remoteFD to -1
623 * so that DNS resolution and connect is retried? */
624 sendto(G.remoteFD, recvbuf, sz+1, MSG_DONTWAIT,
625 &G.remoteAddr->u.sa, G.remoteAddr->len);
629 if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
630 recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
631 split_escape_and_log(recvbuf, sz);
636 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
637 int syslogd_main(int argc ATTRIBUTE_UNUSED, char **argv)
642 #if ENABLE_FEATURE_REMOTE_LOG
643 G.last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
646 /* do normal option parsing */
647 opt_complementary = "=0"; /* no non-option params */
648 getopt32(argv, OPTION_STR, OPTION_PARAM);
650 if (option_mask32 & OPT_mark) // -m
651 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
653 //if (option_mask32 & OPT_nofork) // -n
654 //if (option_mask32 & OPT_outfile) // -O
655 if (option_mask32 & OPT_loglevel) // -l
656 G.logLevel = xatou_range(opt_l, 1, 8);
657 //if (option_mask32 & OPT_small) // -S
658 #if ENABLE_FEATURE_ROTATE_LOGFILE
659 if (option_mask32 & OPT_filesize) // -s
660 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
661 if (option_mask32 & OPT_rotatecnt) // -b
662 G.logFileRotate = xatou_range(opt_b, 0, 99);
664 #if ENABLE_FEATURE_IPC_SYSLOG
666 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
669 /* If they have not specified remote logging, then log locally */
670 if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_remotelog))
671 option_mask32 |= OPT_locallog;
673 /* Store away localhost's name before the fork */
674 G.hostname = safe_gethostname();
675 *strchrnul(G.hostname, '.') = '\0';
677 if (!(option_mask32 & OPT_nofork)) {
678 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
681 write_pidfile("/var/run/syslogd.pid");
683 /* return EXIT_SUCCESS; */