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];
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 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
156 OPT_mark = 1 << OPTBIT_mark ,
157 OPT_nofork = 1 << OPTBIT_nofork ,
158 OPT_outfile = 1 << OPTBIT_outfile ,
159 OPT_loglevel = 1 << OPTBIT_loglevel,
160 OPT_small = 1 << OPTBIT_small ,
161 OPT_filesize = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize )) + 0,
162 OPT_rotatecnt = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt )) + 0,
163 OPT_remotelog = USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_remote )) + 0,
164 OPT_locallog = USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_locallog )) + 0,
165 OPT_circularlog = USE_FEATURE_IPC_SYSLOG( (1 << OPTBIT_circularlog)) + 0,
167 #define OPTION_STR "m:nO:l:S" \
168 USE_FEATURE_ROTATE_LOGFILE("s:" ) \
169 USE_FEATURE_ROTATE_LOGFILE("b:" ) \
170 USE_FEATURE_REMOTE_LOG( "R:" ) \
171 USE_FEATURE_REMOTE_LOG( "L" ) \
172 USE_FEATURE_IPC_SYSLOG( "C::")
173 #define OPTION_DECL *opt_m, *opt_l \
174 USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
175 USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
176 USE_FEATURE_IPC_SYSLOG( ,*opt_C = NULL)
177 #define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \
178 USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
179 USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
180 USE_FEATURE_REMOTE_LOG( ,&G.remoteAddrStr) \
181 USE_FEATURE_IPC_SYSLOG( ,&opt_C)
184 /* circular buffer variables/structures */
185 #if ENABLE_FEATURE_IPC_SYSLOG
187 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
188 #error Sorry, you must set the syslogd buffer size to at least 4KB.
189 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
193 #define KEY_ID ((long)0x414e4547) /* "GENA" */
195 static void ipcsyslog_cleanup(void)
201 shmctl(G.shmid, IPC_RMID, NULL);
203 if (G.s_semid != -1) {
204 semctl(G.s_semid, 0, IPC_RMID, 0);
208 static void ipcsyslog_init(void)
211 printf("shmget(%lx, %d,...)\n", KEY_ID, G.shm_size);
213 G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
215 bb_perror_msg_and_die("shmget");
218 G.shbuf = shmat(G.shmid, NULL, 0);
219 if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
220 bb_perror_msg_and_die("shmat");
223 memset(G.shbuf, 0, G.shm_size);
224 G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
225 /*G.shbuf->tail = 0;*/
227 // we'll trust the OS to set initial semval to 0 (let's hope)
228 G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
229 if (G.s_semid == -1) {
230 if (errno == EEXIST) {
231 G.s_semid = semget(KEY_ID, 2, 0);
235 bb_perror_msg_and_die("semget");
239 /* Write message to shared mem buffer */
240 static void log_to_shmem(const char *msg, int len)
242 int old_tail, new_tail;
244 if (semop(G.s_semid, G.SMwdn, 3) == -1) {
245 bb_perror_msg_and_die("SMwdn");
248 /* Circular Buffer Algorithm:
249 * --------------------------
250 * tail == position where to store next syslog message.
251 * tail's max value is (shbuf->size - 1)
252 * Last byte of buffer is never used and remains NUL.
254 len++; /* length with NUL included */
256 old_tail = G.shbuf->tail;
257 new_tail = old_tail + len;
258 if (new_tail < G.shbuf->size) {
259 /* store message, set new tail */
260 memcpy(G.shbuf->data + old_tail, msg, len);
261 G.shbuf->tail = new_tail;
263 /* k == available buffer space ahead of old tail */
264 int k = G.shbuf->size - old_tail;
265 /* copy what fits to the end of buffer, and repeat */
266 memcpy(G.shbuf->data + old_tail, msg, k);
272 if (semop(G.s_semid, G.SMwup, 1) == -1) {
273 bb_perror_msg_and_die("SMwup");
276 printf("tail:%d\n", G.shbuf->tail);
279 void ipcsyslog_cleanup(void);
280 void ipcsyslog_init(void);
281 void log_to_shmem(const char *msg);
282 #endif /* FEATURE_IPC_SYSLOG */
285 /* Print a message to the log file. */
286 static void log_locally(time_t now, char *msg)
289 int len = strlen(msg);
291 #if ENABLE_FEATURE_IPC_SYSLOG
292 if ((option_mask32 & OPT_circularlog) && G.shbuf) {
293 log_to_shmem(msg, len);
300 if (G.last_log_time != now) {
301 G.last_log_time = now; /* reopen log file every second */
307 G.logFD = device_open(G.logFilePath, O_WRONLY | O_CREAT
308 | O_NOCTTY | O_APPEND | O_NONBLOCK);
310 /* cannot open logfile? - print to /dev/console then */
311 int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
313 fd = 2; /* then stderr, dammit */
314 full_write(fd, msg, len);
319 #if ENABLE_FEATURE_ROTATE_LOGFILE
322 G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode));
323 /* bug (mostly harmless): can wrap around if file > 4gb */
324 G.curFileSize = statf.st_size;
329 fl.l_whence = SEEK_SET;
333 fcntl(G.logFD, F_SETLKW, &fl);
335 #if ENABLE_FEATURE_ROTATE_LOGFILE
336 if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) {
337 if (G.logFileRotate) { /* always 0..99 */
338 int i = strlen(G.logFilePath) + 3 + 1;
341 i = G.logFileRotate - 1;
342 /* rename: f.8 -> f.9; f.7 -> f.8; ... */
344 sprintf(newFile, "%s.%d", G.logFilePath, i);
346 sprintf(oldFile, "%s.%d", G.logFilePath, --i);
347 xrename(oldFile, newFile);
349 /* newFile == "f.0" now */
350 xrename(G.logFilePath, newFile);
352 fcntl(G.logFD, F_SETLKW, &fl);
356 ftruncate(G.logFD, 0);
360 full_write(G.logFD, msg, len);
362 fcntl(G.logFD, F_SETLKW, &fl);
365 static void parse_fac_prio_20(int pri, char *res20)
367 const CODE *c_pri, *c_fac;
370 c_fac = facilitynames;
371 while (c_fac->c_name) {
372 if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
376 /* facility is found, look for prio */
377 c_pri = prioritynames;
378 while (c_pri->c_name) {
379 if (c_pri->c_val != LOG_PRI(pri)) {
383 snprintf(res20, 20, "%s.%s",
384 c_fac->c_name, c_pri->c_name);
387 /* prio not found, bail out */
390 snprintf(res20, 20, "<%d>", pri);
394 /* len parameter is used only for "is there a timestamp?" check.
395 * NB: some callers cheat and supply len==0 when they know
396 * that there is no timestamp, short-circuiting the test. */
397 static void timestamp_and_log(int pri, char *msg, int len)
402 if (len < 16 || msg[3] != ' ' || msg[6] != ' '
403 || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
406 timestamp = ctime(&now) + 4; /* skip day of week */
412 timestamp[15] = '\0';
414 if (option_mask32 & OPT_small)
415 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
418 parse_fac_prio_20(pri, res);
419 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
422 /* Log message locally (to file or shared mem) */
423 log_locally(now, G.printbuf);
426 static void timestamp_and_log_internal(const char *msg)
428 if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
430 timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
433 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
434 * embedded NULs. Split messages on each of these NULs, parse prio,
435 * escape control chars and log each locally. */
436 static void split_escape_and_log(char *tmpbuf, int len)
443 char *q = G.parsebuf;
444 int pri = (LOG_USER | LOG_NOTICE);
447 /* Parse the magic priority number */
448 pri = bb_strtou(p + 1, &p, 10);
451 if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
452 pri = (LOG_USER | LOG_NOTICE);
458 if (!(c & ~0x1f) && c != '\t') {
460 c += '@'; /* ^@, ^A, ^B... */
467 if (LOG_PRI(pri) < G.logLevel)
468 timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
472 static void quit_signal(int sig)
474 timestamp_and_log_internal("syslogd exiting");
475 puts("syslogd exiting");
476 if (ENABLE_FEATURE_IPC_SYSLOG)
478 kill_myself_with_sig(sig);
482 static void do_mark(int sig)
484 if (G.markInterval) {
485 timestamp_and_log_internal("-- MARK --");
486 alarm(G.markInterval);
491 /* Don't inline: prevent struct sockaddr_un to take up space on stack
493 static NOINLINE int create_socket(void)
495 struct sockaddr_un sunx;
499 memset(&sunx, 0, sizeof(sunx));
500 sunx.sun_family = AF_UNIX;
502 /* Unlink old /dev/log or object it points to. */
503 /* (if it exists, bind will fail) */
504 strcpy(sunx.sun_path, "/dev/log");
505 dev_log_name = xmalloc_follow_symlinks("/dev/log");
507 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
510 unlink(sunx.sun_path);
512 sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
513 xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
514 chmod("/dev/log", 0666);
519 #if ENABLE_FEATURE_REMOTE_LOG
520 static int try_to_resolve_remote(void)
523 unsigned now = monotonic_sec();
525 /* Don't resolve name too often - DNS timeouts can be big */
526 if ((now - G.last_dns_resolve) < DNS_WAIT_SEC)
528 G.last_dns_resolve = now;
529 G.remoteAddr = host2sockaddr(G.remoteAddrStr, 514);
533 return socket(G.remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
537 static void do_syslogd(void) ATTRIBUTE_NORETURN;
538 static void do_syslogd(void)
542 /* Set up signal handlers */
548 signal(SIGHUP, SIG_IGN);
549 /* signal(SIGCHLD, SIG_IGN); - why? */
551 signal(SIGALRM, do_mark);
552 alarm(G.markInterval);
554 sock_fd = create_socket();
556 if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
560 timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
565 sz = safe_read(sock_fd, G.recvbuf, MAX_READ - 1);
567 bb_perror_msg_and_die("read from /dev/log");
569 /* Drop trailing '\n' and NULs (typically there is one NUL) */
573 /* man 3 syslog says: "A trailing newline is added when needed".
574 * However, neither glibc nor uclibc do this:
575 * syslog(prio, "test") sends "test\0" to /dev/log,
576 * syslog(prio, "test\n") sends "test\n\0".
577 * IOW: newline is passed verbatim!
578 * I take it to mean that it's syslogd's job
579 * to make those look identical in the log files. */
580 if (G.recvbuf[sz-1] != '\0' && G.recvbuf[sz-1] != '\n')
584 /* TODO: maybe suppress duplicates? */
585 #if ENABLE_FEATURE_REMOTE_LOG
586 /* We are not modifying log messages in any way before send */
587 /* Remote site cannot trust _us_ anyway and need to do validation again */
588 if (G.remoteAddrStr) {
589 if (-1 == G.remoteFD) {
590 G.remoteFD = try_to_resolve_remote();
591 if (-1 == G.remoteFD)
594 /* Stock syslogd sends it '\n'-terminated
595 * over network, mimic that */
596 G.recvbuf[sz] = '\n';
597 /* send message to remote logger, ignore possible error */
598 /* TODO: on some errors, close and set G.remoteFD to -1
599 * so that DNS resolution and connect is retried? */
600 sendto(G.remoteFD, G.recvbuf, sz+1, MSG_DONTWAIT,
601 &G.remoteAddr->u.sa, G.remoteAddr->len);
605 if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
606 G.recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
607 split_escape_and_log(G.recvbuf, sz);
612 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
613 int syslogd_main(int argc, char **argv)
618 #if ENABLE_FEATURE_REMOTE_LOG
619 G.last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
622 /* do normal option parsing */
623 opt_complementary = "=0"; /* no non-option params */
624 getopt32(argv, OPTION_STR, OPTION_PARAM);
626 if (option_mask32 & OPT_mark) // -m
627 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
629 //if (option_mask32 & OPT_nofork) // -n
630 //if (option_mask32 & OPT_outfile) // -O
631 if (option_mask32 & OPT_loglevel) // -l
632 G.logLevel = xatou_range(opt_l, 1, 8);
633 //if (option_mask32 & OPT_small) // -S
634 #if ENABLE_FEATURE_ROTATE_LOGFILE
635 if (option_mask32 & OPT_filesize) // -s
636 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
637 if (option_mask32 & OPT_rotatecnt) // -b
638 G.logFileRotate = xatou_range(opt_b, 0, 99);
640 #if ENABLE_FEATURE_IPC_SYSLOG
642 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
645 /* If they have not specified remote logging, then log locally */
646 if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_remotelog))
647 option_mask32 |= OPT_locallog;
649 /* Store away localhost's name before the fork */
650 G.hostname = safe_gethostname();
651 *strchrnul(G.hostname, '.') = '\0';
653 if (!(option_mask32 & OPT_nofork)) {
654 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
657 write_pidfile("/var/run/syslogd.pid");
659 /* return EXIT_SUCCESS; */