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.
17 * Done in syslogd_and_logger.c:
20 #define SYSLOG_NAMES_CONST
28 #if ENABLE_FEATURE_REMOTE_LOG
29 #include <netinet/in.h>
32 #if ENABLE_FEATURE_IPC_SYSLOG
41 /* MARK code is not very useful, is bloat, and broken:
42 * can deadlock if alarmed to make MARK while writing to IPC buffer
43 * (semaphores are down but do_mark routine tries to down them again) */
46 /* Write locking does not seem to be useful either */
51 DNS_WAIT_SEC
= 2 * 60,
54 /* Semaphore operation structures */
56 int32_t size
; /* size of data - 1 */
57 int32_t tail
; /* end of message list */
58 char data
[1]; /* data/messages */
61 /* Allows us to have smaller initializer. Ugly. */
63 const char *logFilePath; \
65 /* interval between marks in seconds */ \
66 /*int markInterval;*/ \
67 /* level of messages to be logged */ \
69 USE_FEATURE_ROTATE_LOGFILE( \
70 /* max size of file before rotation */ \
71 unsigned logFileSize; \
72 /* number of rotated message files */ \
73 unsigned logFileRotate; \
74 unsigned curFileSize; \
77 USE_FEATURE_REMOTE_LOG( \
78 /* udp socket for remote logging */ \
80 len_and_sockaddr* remoteAddr; \
82 USE_FEATURE_IPC_SYSLOG( \
83 int shmid; /* ipc shared memory id */ \
84 int s_semid; /* ipc semaphore id */ \
86 struct sembuf SMwup[1]; \
87 struct sembuf SMwdn[3]; \
97 #if ENABLE_FEATURE_REMOTE_LOG
98 unsigned last_dns_resolve
;
102 #if ENABLE_FEATURE_IPC_SYSLOG
103 struct shbuf_ds
*shbuf
;
105 time_t last_log_time
;
106 /* localhost's name. We print only first 64 chars */
109 /* We recv into recvbuf... */
110 char recvbuf
[MAX_READ
* (1 + ENABLE_FEATURE_SYSLOGD_DUP
)];
111 /* ...then copy to parsebuf, escaping control chars */
112 /* (can grow x2 max) */
113 char parsebuf
[MAX_READ
*2];
114 /* ...then sprintf into printbuf, adding timestamp (15 chars),
115 * host (64), fac.prio (20) to the message */
116 /* (growth by: 15 + 64 + 20 + delims = ~110) */
117 char printbuf
[MAX_READ
*2 + 128];
120 static const struct init_globals init_data
= {
121 .logFilePath
= "/var/log/messages",
124 .markInterval
= 20 * 60,
127 #if ENABLE_FEATURE_ROTATE_LOGFILE
128 .logFileSize
= 200 * 1024,
131 #if ENABLE_FEATURE_REMOTE_LOG
134 #if ENABLE_FEATURE_IPC_SYSLOG
137 .shm_size
= ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
)*1024), // default shm size
138 .SMwup
= { {1, -1, IPC_NOWAIT
} },
139 .SMwdn
= { {0, 0}, {1, 0}, {1, +1} },
143 #define G (*ptr_to_globals)
144 #define INIT_G() do { \
145 SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
151 OPTBIT_mark
= 0, // -m
153 OPTBIT_outfile
, // -O
154 OPTBIT_loglevel
, // -l
156 USE_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize
,) // -s
157 USE_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt
,) // -b
158 USE_FEATURE_REMOTE_LOG( OPTBIT_remotelog
,) // -R
159 USE_FEATURE_REMOTE_LOG( OPTBIT_locallog
,) // -L
160 USE_FEATURE_IPC_SYSLOG( OPTBIT_circularlog
,) // -C
161 USE_FEATURE_SYSLOGD_DUP( OPTBIT_dup
,) // -D
163 OPT_mark
= 1 << OPTBIT_mark
,
164 OPT_nofork
= 1 << OPTBIT_nofork
,
165 OPT_outfile
= 1 << OPTBIT_outfile
,
166 OPT_loglevel
= 1 << OPTBIT_loglevel
,
167 OPT_small
= 1 << OPTBIT_small
,
168 OPT_filesize
= USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize
)) + 0,
169 OPT_rotatecnt
= USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt
)) + 0,
170 OPT_remotelog
= USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_remotelog
)) + 0,
171 OPT_locallog
= USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_locallog
)) + 0,
172 OPT_circularlog
= USE_FEATURE_IPC_SYSLOG( (1 << OPTBIT_circularlog
)) + 0,
173 OPT_dup
= USE_FEATURE_SYSLOGD_DUP( (1 << OPTBIT_dup
)) + 0,
175 #define OPTION_STR "m:nO:l:S" \
176 USE_FEATURE_ROTATE_LOGFILE("s:" ) \
177 USE_FEATURE_ROTATE_LOGFILE("b:" ) \
178 USE_FEATURE_REMOTE_LOG( "R:" ) \
179 USE_FEATURE_REMOTE_LOG( "L" ) \
180 USE_FEATURE_IPC_SYSLOG( "C::") \
181 USE_FEATURE_SYSLOGD_DUP( "D" )
182 #define OPTION_DECL *opt_m, *opt_l \
183 USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
184 USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
185 USE_FEATURE_IPC_SYSLOG( ,*opt_C = NULL)
186 #define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \
187 USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
188 USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
189 USE_FEATURE_REMOTE_LOG( ,&G.remoteAddrStr) \
190 USE_FEATURE_IPC_SYSLOG( ,&opt_C)
193 /* circular buffer variables/structures */
194 #if ENABLE_FEATURE_IPC_SYSLOG
196 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
197 #error Sorry, you must set the syslogd buffer size to at least 4KB.
198 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
201 /* our shared key (syslogd.c and logread.c must be in sync) */
202 enum { KEY_ID
= 0x414e4547 }; /* "GENA" */
204 static void ipcsyslog_cleanup(void)
210 shmctl(G
.shmid
, IPC_RMID
, NULL
);
212 if (G
.s_semid
!= -1) {
213 semctl(G
.s_semid
, 0, IPC_RMID
, 0);
217 static void ipcsyslog_init(void)
220 printf("shmget(%x, %d,...)\n", (int)KEY_ID
, G
.shm_size
);
222 G
.shmid
= shmget(KEY_ID
, G
.shm_size
, IPC_CREAT
| 0644);
224 bb_perror_msg_and_die("shmget");
227 G
.shbuf
= shmat(G
.shmid
, NULL
, 0);
228 if (G
.shbuf
== (void*) -1L) { /* shmat has bizarre error return */
229 bb_perror_msg_and_die("shmat");
232 memset(G
.shbuf
, 0, G
.shm_size
);
233 G
.shbuf
->size
= G
.shm_size
- offsetof(struct shbuf_ds
, data
) - 1;
234 /*G.shbuf->tail = 0;*/
236 // we'll trust the OS to set initial semval to 0 (let's hope)
237 G
.s_semid
= semget(KEY_ID
, 2, IPC_CREAT
| IPC_EXCL
| 1023);
238 if (G
.s_semid
== -1) {
239 if (errno
== EEXIST
) {
240 G
.s_semid
= semget(KEY_ID
, 2, 0);
244 bb_perror_msg_and_die("semget");
248 /* Write message to shared mem buffer */
249 static void log_to_shmem(const char *msg
, int len
)
251 int old_tail
, new_tail
;
253 if (semop(G
.s_semid
, G
.SMwdn
, 3) == -1) {
254 bb_perror_msg_and_die("SMwdn");
257 /* Circular Buffer Algorithm:
258 * --------------------------
259 * tail == position where to store next syslog message.
260 * tail's max value is (shbuf->size - 1)
261 * Last byte of buffer is never used and remains NUL.
263 len
++; /* length with NUL included */
265 old_tail
= G
.shbuf
->tail
;
266 new_tail
= old_tail
+ len
;
267 if (new_tail
< G
.shbuf
->size
) {
268 /* store message, set new tail */
269 memcpy(G
.shbuf
->data
+ old_tail
, msg
, len
);
270 G
.shbuf
->tail
= new_tail
;
272 /* k == available buffer space ahead of old tail */
273 int k
= G
.shbuf
->size
- old_tail
;
274 /* copy what fits to the end of buffer, and repeat */
275 memcpy(G
.shbuf
->data
+ old_tail
, msg
, k
);
281 if (semop(G
.s_semid
, G
.SMwup
, 1) == -1) {
282 bb_perror_msg_and_die("SMwup");
285 printf("tail:%d\n", G
.shbuf
->tail
);
288 void ipcsyslog_cleanup(void);
289 void ipcsyslog_init(void);
290 void log_to_shmem(const char *msg
);
291 #endif /* FEATURE_IPC_SYSLOG */
294 /* Print a message to the log file. */
295 static void log_locally(time_t now
, char *msg
)
297 #ifdef SYSLOGD_WRLOCK
300 int len
= strlen(msg
);
302 #if ENABLE_FEATURE_IPC_SYSLOG
303 if ((option_mask32
& OPT_circularlog
) && G
.shbuf
) {
304 log_to_shmem(msg
, len
);
309 /* Reopen log file every second. This allows admin
310 * to delete the file and not worry about restarting us.
311 * This costs almost nothing since it happens
312 * _at most_ once a second.
316 if (G
.last_log_time
!= now
) {
317 G
.last_log_time
= now
;
323 G
.logFD
= open(G
.logFilePath
, O_WRONLY
| O_CREAT
324 | O_NOCTTY
| O_APPEND
| O_NONBLOCK
,
327 /* cannot open logfile? - print to /dev/console then */
328 int fd
= device_open(DEV_CONSOLE
, O_WRONLY
| O_NOCTTY
| O_NONBLOCK
);
330 fd
= 2; /* then stderr, dammit */
331 full_write(fd
, msg
, len
);
336 #if ENABLE_FEATURE_ROTATE_LOGFILE
339 G
.isRegular
= (fstat(G
.logFD
, &statf
) == 0 && S_ISREG(statf
.st_mode
));
340 /* bug (mostly harmless): can wrap around if file > 4gb */
341 G
.curFileSize
= statf
.st_size
;
346 #ifdef SYSLOGD_WRLOCK
347 fl
.l_whence
= SEEK_SET
;
351 fcntl(G
.logFD
, F_SETLKW
, &fl
);
354 #if ENABLE_FEATURE_ROTATE_LOGFILE
355 if (G
.logFileSize
&& G
.isRegular
&& G
.curFileSize
> G
.logFileSize
) {
356 if (G
.logFileRotate
) { /* always 0..99 */
357 int i
= strlen(G
.logFilePath
) + 3 + 1;
360 i
= G
.logFileRotate
- 1;
361 /* rename: f.8 -> f.9; f.7 -> f.8; ... */
363 sprintf(newFile
, "%s.%d", G
.logFilePath
, i
);
365 sprintf(oldFile
, "%s.%d", G
.logFilePath
, --i
);
366 /* ignore errors - file might be missing */
367 rename(oldFile
, newFile
);
369 /* newFile == "f.0" now */
370 rename(G
.logFilePath
, newFile
);
371 #ifdef SYSLOGD_WRLOCK
373 fcntl(G
.logFD
, F_SETLKW
, &fl
);
378 ftruncate(G
.logFD
, 0);
382 full_write(G
.logFD
, msg
, len
);
383 #ifdef SYSLOGD_WRLOCK
385 fcntl(G
.logFD
, F_SETLKW
, &fl
);
389 static void parse_fac_prio_20(int pri
, char *res20
)
391 const CODE
*c_pri
, *c_fac
;
394 c_fac
= facilitynames
;
395 while (c_fac
->c_name
) {
396 if (c_fac
->c_val
!= (LOG_FAC(pri
) << 3)) {
400 /* facility is found, look for prio */
401 c_pri
= prioritynames
;
402 while (c_pri
->c_name
) {
403 if (c_pri
->c_val
!= LOG_PRI(pri
)) {
407 snprintf(res20
, 20, "%s.%s",
408 c_fac
->c_name
, c_pri
->c_name
);
411 /* prio not found, bail out */
414 snprintf(res20
, 20, "<%d>", pri
);
418 /* len parameter is used only for "is there a timestamp?" check.
419 * NB: some callers cheat and supply len==0 when they know
420 * that there is no timestamp, short-circuiting the test. */
421 static void timestamp_and_log(int pri
, char *msg
, int len
)
426 if (len
< 16 || msg
[3] != ' ' || msg
[6] != ' '
427 || msg
[9] != ':' || msg
[12] != ':' || msg
[15] != ' '
430 timestamp
= ctime(&now
) + 4; /* skip day of week */
436 timestamp
[15] = '\0';
438 if (option_mask32
& OPT_small
)
439 sprintf(G
.printbuf
, "%s %s\n", timestamp
, msg
);
442 parse_fac_prio_20(pri
, res
);
443 sprintf(G
.printbuf
, "%s %.64s %s %s\n", timestamp
, G
.hostname
, res
, msg
);
446 /* Log message locally (to file or shared mem) */
447 log_locally(now
, G
.printbuf
);
450 static void timestamp_and_log_internal(const char *msg
)
453 if (ENABLE_FEATURE_REMOTE_LOG
&& !(option_mask32
& OPT_locallog
))
455 timestamp_and_log(LOG_SYSLOG
| LOG_INFO
, (char*)msg
, 0);
458 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
459 * embedded NULs. Split messages on each of these NULs, parse prio,
460 * escape control chars and log each locally. */
461 static void split_escape_and_log(char *tmpbuf
, int len
)
468 char *q
= G
.parsebuf
;
469 int pri
= (LOG_USER
| LOG_NOTICE
);
472 /* Parse the magic priority number */
473 pri
= bb_strtou(p
+ 1, &p
, 10);
476 if (pri
& ~(LOG_FACMASK
| LOG_PRIMASK
))
477 pri
= (LOG_USER
| LOG_NOTICE
);
483 if (!(c
& ~0x1f) && c
!= '\t') {
485 c
+= '@'; /* ^@, ^A, ^B... */
492 if (LOG_PRI(pri
) < G
.logLevel
)
493 timestamp_and_log(pri
, G
.parsebuf
, q
- G
.parsebuf
);
498 static void do_mark(int sig
)
500 if (G
.markInterval
) {
501 timestamp_and_log_internal("-- MARK --");
502 alarm(G
.markInterval
);
507 /* Don't inline: prevent struct sockaddr_un to take up space on stack
509 static NOINLINE
int create_socket(void)
511 struct sockaddr_un sunx
;
515 memset(&sunx
, 0, sizeof(sunx
));
516 sunx
.sun_family
= AF_UNIX
;
518 /* Unlink old /dev/log or object it points to. */
519 /* (if it exists, bind will fail) */
520 strcpy(sunx
.sun_path
, "/dev/log");
521 dev_log_name
= xmalloc_follow_symlinks("/dev/log");
523 safe_strncpy(sunx
.sun_path
, dev_log_name
, sizeof(sunx
.sun_path
));
526 unlink(sunx
.sun_path
);
528 sock_fd
= xsocket(AF_UNIX
, SOCK_DGRAM
, 0);
529 xbind(sock_fd
, (struct sockaddr
*) &sunx
, sizeof(sunx
));
530 chmod("/dev/log", 0666);
535 #if ENABLE_FEATURE_REMOTE_LOG
536 static int try_to_resolve_remote(void)
539 unsigned now
= monotonic_sec();
541 /* Don't resolve name too often - DNS timeouts can be big */
542 if ((now
- G
.last_dns_resolve
) < DNS_WAIT_SEC
)
544 G
.last_dns_resolve
= now
;
545 G
.remoteAddr
= host2sockaddr(G
.remoteAddrStr
, 514);
549 return socket(G
.remoteAddr
->u
.sa
.sa_family
, SOCK_DGRAM
, 0);
553 static void do_syslogd(void) NORETURN
;
554 static void do_syslogd(void)
557 #if ENABLE_FEATURE_SYSLOGD_DUP
560 char *recvbuf
= G
.recvbuf
;
562 #define recvbuf (G.recvbuf)
565 /* Set up signal handlers (so that they interrupt read()) */
566 signal_no_SA_RESTART_empty_mask(SIGTERM
, record_signo
);
567 signal_no_SA_RESTART_empty_mask(SIGINT
, record_signo
);
568 //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo);
569 signal(SIGHUP
, SIG_IGN
);
571 signal(SIGALRM
, do_mark
);
572 alarm(G
.markInterval
);
574 sock_fd
= create_socket();
576 if (ENABLE_FEATURE_IPC_SYSLOG
&& (option_mask32
& OPT_circularlog
)) {
580 timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER
);
582 while (!bb_got_signal
) {
585 #if ENABLE_FEATURE_SYSLOGD_DUP
587 if (recvbuf
== G
.recvbuf
)
588 recvbuf
= G
.recvbuf
+ MAX_READ
;
593 sz
= read(sock_fd
, recvbuf
, MAX_READ
- 1);
596 bb_perror_msg("read from /dev/log");
600 /* Drop trailing '\n' and NULs (typically there is one NUL) */
604 /* man 3 syslog says: "A trailing newline is added when needed".
605 * However, neither glibc nor uclibc do this:
606 * syslog(prio, "test") sends "test\0" to /dev/log,
607 * syslog(prio, "test\n") sends "test\n\0".
608 * IOW: newline is passed verbatim!
609 * I take it to mean that it's syslogd's job
610 * to make those look identical in the log files. */
611 if (recvbuf
[sz
-1] != '\0' && recvbuf
[sz
-1] != '\n')
615 #if ENABLE_FEATURE_SYSLOGD_DUP
616 if ((option_mask32
& OPT_dup
) && (sz
== last_sz
))
617 if (memcmp(last_buf
, recvbuf
, sz
) == 0)
621 #if ENABLE_FEATURE_REMOTE_LOG
622 /* We are not modifying log messages in any way before send */
623 /* Remote site cannot trust _us_ anyway and need to do validation again */
624 if (G
.remoteAddrStr
) {
625 if (-1 == G
.remoteFD
) {
626 G
.remoteFD
= try_to_resolve_remote();
627 if (-1 == G
.remoteFD
)
630 /* Stock syslogd sends it '\n'-terminated
631 * over network, mimic that */
633 /* send message to remote logger, ignore possible error */
634 /* TODO: on some errors, close and set G.remoteFD to -1
635 * so that DNS resolution and connect is retried? */
636 sendto(G
.remoteFD
, recvbuf
, sz
+1, MSG_DONTWAIT
,
637 &G
.remoteAddr
->u
.sa
, G
.remoteAddr
->len
);
641 if (!ENABLE_FEATURE_REMOTE_LOG
|| (option_mask32
& OPT_locallog
)) {
642 recvbuf
[sz
] = '\0'; /* ensure it *is* NUL terminated */
643 split_escape_and_log(recvbuf
, sz
);
645 } /* while (!bb_got_signal) */
647 timestamp_and_log_internal("syslogd exiting");
648 puts("syslogd exiting");
649 if (ENABLE_FEATURE_IPC_SYSLOG
)
651 kill_myself_with_sig(bb_got_signal
);
655 int syslogd_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
656 int syslogd_main(int argc UNUSED_PARAM
, char **argv
)
662 #if ENABLE_FEATURE_REMOTE_LOG
663 G
.last_dns_resolve
= monotonic_sec() - DNS_WAIT_SEC
- 1;
666 /* do normal option parsing */
667 opt_complementary
= "=0"; /* no non-option params */
668 opts
= getopt32(argv
, OPTION_STR
, OPTION_PARAM
);
670 if (opts
& OPT_mark
) // -m
671 G
.markInterval
= xatou_range(opt_m
, 0, INT_MAX
/60) * 60;
673 //if (opts & OPT_nofork) // -n
674 //if (opts & OPT_outfile) // -O
675 if (opts
& OPT_loglevel
) // -l
676 G
.logLevel
= xatou_range(opt_l
, 1, 8);
677 //if (opts & OPT_small) // -S
678 #if ENABLE_FEATURE_ROTATE_LOGFILE
679 if (opts
& OPT_filesize
) // -s
680 G
.logFileSize
= xatou_range(opt_s
, 0, INT_MAX
/1024) * 1024;
681 if (opts
& OPT_rotatecnt
) // -b
682 G
.logFileRotate
= xatou_range(opt_b
, 0, 99);
684 #if ENABLE_FEATURE_IPC_SYSLOG
686 G
.shm_size
= xatoul_range(opt_C
, 4, INT_MAX
/1024) * 1024;
689 /* If they have not specified remote logging, then log locally */
690 if (ENABLE_FEATURE_REMOTE_LOG
&& !(opts
& OPT_remotelog
)) // -R
691 option_mask32
|= OPT_locallog
;
693 /* Store away localhost's name before the fork */
694 G
.hostname
= safe_gethostname();
695 *strchrnul(G
.hostname
, '.') = '\0';
697 if (!(opts
& OPT_nofork
)) {
698 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT
, argv
);
701 write_pidfile("/var/run/syslogd.pid");
703 /* return EXIT_SUCCESS; */
706 /* Clean up. Needed because we are included from syslogd_and_logger.c */
709 #undef SYSLOGD_WRLOCK