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 GPLv2 or later, see file LICENSE in this source tree.
15 //config:config SYSLOGD
16 //config: bool "syslogd"
19 //config: The syslogd utility is used to record logs of all the
20 //config: significant events that occur on a system. Every
21 //config: message that is logged records the date and time of the
22 //config: event, and will generally also record the name of the
23 //config: application that generated the message. When used in
24 //config: conjunction with klogd, messages from the Linux kernel
25 //config: can also be recorded. This is terribly useful,
26 //config: especially for finding what happened when something goes
27 //config: wrong. And something almost always will go wrong if
28 //config: you wait long enough....
30 //config:config FEATURE_ROTATE_LOGFILE
31 //config: bool "Rotate message files"
33 //config: depends on SYSLOGD
35 //config: This enables syslogd to rotate the message files
36 //config: on his own. No need to use an external rotatescript.
38 //config:config FEATURE_REMOTE_LOG
39 //config: bool "Remote Log support"
41 //config: depends on SYSLOGD
43 //config: When you enable this feature, the syslogd utility can
44 //config: be used to send system log messages to another system
45 //config: connected via a network. This allows the remote
46 //config: machine to log all the system messages, which can be
47 //config: terribly useful for reducing the number of serial
48 //config: cables you use. It can also be a very good security
49 //config: measure to prevent system logs from being tampered with
50 //config: by an intruder.
52 //config:config FEATURE_SYSLOGD_DUP
53 //config: bool "Support -D (drop dups) option"
55 //config: depends on SYSLOGD
57 //config: Option -D instructs syslogd to drop consecutive messages
58 //config: which are totally the same.
60 //config:config FEATURE_SYSLOGD_CFG
61 //config: bool "Support syslog.conf"
63 //config: depends on SYSLOGD
65 //config: Supports restricted syslogd config. See docs/syslog.conf.txt
67 //config:config FEATURE_SYSLOGD_READ_BUFFER_SIZE
68 //config: int "Read buffer size in bytes"
70 //config: range 256 20000
71 //config: depends on SYSLOGD
73 //config: This option sets the size of the syslog read buffer.
74 //config: Actual memory usage increases around five times the
75 //config: change done here.
77 //config:config FEATURE_IPC_SYSLOG
78 //config: bool "Circular Buffer support"
80 //config: depends on SYSLOGD
82 //config: When you enable this feature, the syslogd utility will
83 //config: use a circular buffer to record system log messages.
84 //config: When the buffer is filled it will continue to overwrite
85 //config: the oldest messages. This can be very useful for
86 //config: systems with little or no permanent storage, since
87 //config: otherwise system logs can eventually fill up your
88 //config: entire filesystem, which may cause your system to
89 //config: break badly.
91 //config:config FEATURE_IPC_SYSLOG_BUFFER_SIZE
92 //config: int "Circular buffer size in Kbytes (minimum 4KB)"
94 //config: range 4 2147483647
95 //config: depends on FEATURE_IPC_SYSLOG
97 //config: This option sets the size of the circular buffer
98 //config: used to record system log messages.
100 //config:config FEATURE_KMSG_SYSLOG
101 //config: bool "Linux kernel printk buffer support"
103 //config: depends on SYSLOGD
104 //config: select PLATFORM_LINUX
106 //config: When you enable this feature, the syslogd utility will
107 //config: write system log message to the Linux kernel's printk buffer.
108 //config: This can be used as a smaller alternative to the syslogd IPC
109 //config: support, as klogd and logread aren't needed.
111 //config: NOTICE: Syslog facilities in log entries needs kernel 3.5+.
113 //applet:IF_SYSLOGD(APPLET(syslogd, BB_DIR_SBIN, BB_SUID_DROP))
115 //kbuild:lib-$(CONFIG_SYSLOGD) += syslogd_and_logger.o
117 //usage:#define syslogd_trivial_usage
119 //usage:#define syslogd_full_usage "\n\n"
120 //usage: "System logging utility\n"
121 //usage: IF_NOT_FEATURE_SYSLOGD_CFG(
122 //usage: "(this version of syslogd ignores /etc/syslog.conf)\n"
124 //usage: "\n -n Run in foreground"
125 //usage: IF_FEATURE_REMOTE_LOG(
126 //usage: "\n -R HOST[:PORT] Log to HOST:PORT (default PORT:514)"
127 //usage: "\n -L Log locally and via network (default is network only if -R)"
129 //usage: IF_FEATURE_IPC_SYSLOG(
130 /* NB: -Csize shouldn't have space (because size is optional) */
131 //usage: "\n -C[size_kb] Log to shared mem buffer (use logread to read it)"
133 //usage: IF_FEATURE_KMSG_SYSLOG(
134 //usage: "\n -K Log to kernel printk buffer (use dmesg to read it)"
136 //usage: "\n -O FILE Log to FILE (default:/var/log/messages, stdout if -)"
137 //usage: IF_FEATURE_ROTATE_LOGFILE(
138 //usage: "\n -s SIZE Max size (KB) before rotation (default:200KB, 0=off)"
139 //usage: "\n -b N N rotated logs to keep (default:1, max=99, 0=purge)"
141 //usage: "\n -l N Log only messages more urgent than prio N (1-8)"
142 //usage: "\n -S Smaller output"
143 //usage: IF_FEATURE_SYSLOGD_DUP(
144 //usage: "\n -D Drop duplicates"
146 //usage: IF_FEATURE_SYSLOGD_CFG(
147 //usage: "\n -f FILE Use FILE as config (default:/etc/syslog.conf)"
149 /* //usage: "\n -m MIN Minutes between MARK lines (default:20, 0=off)" */
151 //usage:#define syslogd_example_usage
152 //usage: "$ syslogd -R masterlog:514\n"
153 //usage: "$ syslogd -R 192.168.1.1:601\n"
156 * Done in syslogd_and_logger.c:
159 #define SYSLOG_NAMES_CONST
163 #define _PATH_LOG "/dev/log"
169 #if ENABLE_FEATURE_REMOTE_LOG
170 #include <netinet/in.h>
173 #if ENABLE_FEATURE_IPC_SYSLOG
182 /* MARK code is not very useful, is bloat, and broken:
183 * can deadlock if alarmed to make MARK while writing to IPC buffer
184 * (semaphores are down but do_mark routine tries to down them again) */
187 /* Write locking does not seem to be useful either */
188 #undef SYSLOGD_WRLOCK
191 MAX_READ = CONFIG_FEATURE_SYSLOGD_READ_BUFFER_SIZE,
192 DNS_WAIT_SEC = 2 * 60,
195 /* Semaphore operation structures */
197 int32_t size; /* size of data - 1 */
198 int32_t tail; /* end of message list */
199 char data[1]; /* data/messages */
202 #if ENABLE_FEATURE_REMOTE_LOG
205 unsigned last_dns_resolve;
206 len_and_sockaddr *remoteAddr;
207 const char *remoteHostname;
211 typedef struct logFile_t {
214 time_t last_log_time;
215 #if ENABLE_FEATURE_ROTATE_LOGFILE
221 #if ENABLE_FEATURE_SYSLOGD_CFG
222 typedef struct logRule_t {
223 uint8_t enabled_facility_priomap[LOG_NFACILITIES];
224 struct logFile_t *file;
225 struct logRule_t *next;
229 /* Allows us to have smaller initializer. Ugly. */
232 /* interval between marks in seconds */ \
233 /*int markInterval;*/ \
234 /* level of messages to be logged */ \
236 IF_FEATURE_ROTATE_LOGFILE( \
237 /* max size of file before rotation */ \
238 unsigned logFileSize; \
239 /* number of rotated message files */ \
240 unsigned logFileRotate; \
242 IF_FEATURE_IPC_SYSLOG( \
243 int shmid; /* ipc shared memory id */ \
244 int s_semid; /* ipc semaphore id */ \
246 struct sembuf SMwup[1]; \
247 struct sembuf SMwdn[3]; \
249 IF_FEATURE_SYSLOGD_CFG( \
250 logRule_t *log_rules; \
252 IF_FEATURE_KMSG_SYSLOG( \
257 struct init_globals {
264 #if ENABLE_FEATURE_REMOTE_LOG
265 llist_t *remoteHosts;
267 #if ENABLE_FEATURE_IPC_SYSLOG
268 struct shbuf_ds *shbuf;
270 /* localhost's name. We print only first 64 chars */
273 /* We recv into recvbuf... */
274 char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
275 /* ...then copy to parsebuf, escaping control chars */
276 /* (can grow x2 max) */
277 char parsebuf[MAX_READ*2];
278 /* ...then sprintf into printbuf, adding timestamp (15 chars),
279 * host (64), fac.prio (20) to the message */
280 /* (growth by: 15 + 64 + 20 + delims = ~110) */
281 char printbuf[MAX_READ*2 + 128];
284 static const struct init_globals init_data = {
286 .path = "/var/log/messages",
290 .markInterval = 20 * 60,
293 #if ENABLE_FEATURE_ROTATE_LOGFILE
294 .logFileSize = 200 * 1024,
297 #if ENABLE_FEATURE_IPC_SYSLOG
300 .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), /* default shm size */
301 .SMwup = { {1, -1, IPC_NOWAIT} },
302 .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
306 #define G (*ptr_to_globals)
307 #define INIT_G() do { \
308 SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
314 OPTBIT_mark = 0, // -m
316 OPTBIT_outfile, // -O
317 OPTBIT_loglevel, // -l
319 IF_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize ,) // -s
320 IF_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt ,) // -b
321 IF_FEATURE_REMOTE_LOG( OPTBIT_remotelog ,) // -R
322 IF_FEATURE_REMOTE_LOG( OPTBIT_locallog ,) // -L
323 IF_FEATURE_IPC_SYSLOG( OPTBIT_circularlog,) // -C
324 IF_FEATURE_SYSLOGD_DUP( OPTBIT_dup ,) // -D
325 IF_FEATURE_SYSLOGD_CFG( OPTBIT_cfg ,) // -f
326 IF_FEATURE_KMSG_SYSLOG( OPTBIT_kmsg ,) // -K
328 OPT_mark = 1 << OPTBIT_mark ,
329 OPT_nofork = 1 << OPTBIT_nofork ,
330 OPT_outfile = 1 << OPTBIT_outfile ,
331 OPT_loglevel = 1 << OPTBIT_loglevel,
332 OPT_small = 1 << OPTBIT_small ,
333 OPT_filesize = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize )) + 0,
334 OPT_rotatecnt = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt )) + 0,
335 OPT_remotelog = IF_FEATURE_REMOTE_LOG( (1 << OPTBIT_remotelog )) + 0,
336 OPT_locallog = IF_FEATURE_REMOTE_LOG( (1 << OPTBIT_locallog )) + 0,
337 OPT_circularlog = IF_FEATURE_IPC_SYSLOG( (1 << OPTBIT_circularlog)) + 0,
338 OPT_dup = IF_FEATURE_SYSLOGD_DUP( (1 << OPTBIT_dup )) + 0,
339 OPT_cfg = IF_FEATURE_SYSLOGD_CFG( (1 << OPTBIT_cfg )) + 0,
340 OPT_kmsg = IF_FEATURE_KMSG_SYSLOG( (1 << OPTBIT_kmsg )) + 0,
342 #define OPTION_STR "m:nO:l:S" \
343 IF_FEATURE_ROTATE_LOGFILE("s:" ) \
344 IF_FEATURE_ROTATE_LOGFILE("b:" ) \
345 IF_FEATURE_REMOTE_LOG( "R:" ) \
346 IF_FEATURE_REMOTE_LOG( "L" ) \
347 IF_FEATURE_IPC_SYSLOG( "C::") \
348 IF_FEATURE_SYSLOGD_DUP( "D" ) \
349 IF_FEATURE_SYSLOGD_CFG( "f:" ) \
350 IF_FEATURE_KMSG_SYSLOG( "K" )
351 #define OPTION_DECL *opt_m, *opt_l \
352 IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \
353 IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \
354 IF_FEATURE_IPC_SYSLOG( ,*opt_C = NULL) \
355 IF_FEATURE_SYSLOGD_CFG( ,*opt_f = NULL)
356 #define OPTION_PARAM &opt_m, &(G.logFile.path), &opt_l \
357 IF_FEATURE_ROTATE_LOGFILE(,&opt_s) \
358 IF_FEATURE_ROTATE_LOGFILE(,&opt_b) \
359 IF_FEATURE_REMOTE_LOG( ,&remoteAddrList) \
360 IF_FEATURE_IPC_SYSLOG( ,&opt_C) \
361 IF_FEATURE_SYSLOGD_CFG( ,&opt_f)
364 #if ENABLE_FEATURE_SYSLOGD_CFG
365 static const CODE* find_by_name(char *name, const CODE* c_set)
367 for (; c_set->c_name; c_set++) {
368 if (strcmp(name, c_set->c_name) == 0)
374 static const CODE* find_by_val(int val, const CODE* c_set)
376 for (; c_set->c_name; c_set++) {
377 if (c_set->c_val == val)
383 #if ENABLE_FEATURE_SYSLOGD_CFG
384 static void parse_syslogdcfg(const char *file)
388 /* tok[0] set of selectors */
389 /* tok[1] file name */
390 /* tok[2] has to be NULL */
394 parser = config_open2(file ? file : "/etc/syslog.conf",
395 file ? xfopen_for_read : fopen_for_read);
397 /* didn't find default /etc/syslog.conf */
398 /* proceed as if we built busybox without config support */
401 /* use ptr to ptr to avoid checking whether head was initialized */
402 pp_rule = &G.log_rules;
403 /* iterate through lines of config, skipping comments */
404 while (config_read(parser, tok, 3, 2, "# \t", PARSE_NORMAL | PARSE_MIN_DIE)) {
408 /* unexpected trailing token? */
412 cur_rule = *pp_rule = xzalloc(sizeof(*cur_rule));
414 cur_selector = tok[0];
415 /* iterate through selectors: "kern.info;kern.!err;..." */
419 uint8_t negated_prio; /* "kern.!err" */
420 uint8_t single_prio; /* "kern.=err" */
421 uint32_t facmap; /* bitmap of enabled facilities */
422 uint8_t primap; /* bitmap of enabled priorities */
425 next_selector = strchr(cur_selector, ';');
427 *next_selector++ = '\0';
429 t = strchr(cur_selector, '.');
432 *t++ = '\0'; /* separate facility from priority */
447 primap = 0xff; /* all 8 log levels enabled */
450 code = find_by_name(t, prioritynames);
454 priority = code->c_val;
455 if (priority == INTERNAL_NOPRI) {
456 /* ensure we take "enabled_facility_priomap[fac] &= 0" branch below */
459 priority = 1 << priority;
472 if (*cur_selector == '*')
473 facmap = (1<<LOG_NFACILITIES) - 1;
478 /* iterate through facilities: "kern,daemon.<priospec>" */
480 next_facility = strchr(t, ',');
482 *next_facility++ = '\0';
483 code = find_by_name(t, facilitynames);
486 /* "mark" is not a real facility, skip it */
487 if (code->c_val != INTERNAL_MARK)
488 facmap |= 1<<(LOG_FAC(code->c_val));
493 /* merge result with previous selectors */
494 for (i = 0; i < LOG_NFACILITIES; ++i) {
495 if (!(facmap & (1<<i)))
498 cur_rule->enabled_facility_priomap[i] &= primap;
500 cur_rule->enabled_facility_priomap[i] |= primap;
503 cur_selector = next_selector;
504 } while (cur_selector);
506 /* check whether current file name was mentioned in previous rules or
507 * as global logfile (G.logFile).
509 if (strcmp(G.logFile.path, tok[1]) == 0) {
510 cur_rule->file = &G.logFile;
513 /* temporarily use cur_rule as iterator, but *pp_rule still points
514 * to currently processing rule entry.
515 * NOTE: *pp_rule points to the current (and last in the list) rule.
517 for (cur_rule = G.log_rules; cur_rule != *pp_rule; cur_rule = cur_rule->next) {
518 if (strcmp(cur_rule->file->path, tok[1]) == 0) {
519 /* found - reuse the same file structure */
520 (*pp_rule)->file = cur_rule->file;
525 cur_rule->file = xzalloc(sizeof(*cur_rule->file));
526 cur_rule->file->fd = -1;
527 cur_rule->file->path = xstrdup(tok[1]);
529 pp_rule = &cur_rule->next;
531 config_close(parser);
535 bb_error_msg_and_die("error in '%s' at line %d",
536 file ? file : "/etc/syslog.conf",
541 /* circular buffer variables/structures */
542 #if ENABLE_FEATURE_IPC_SYSLOG
544 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
545 #error Sorry, you must set the syslogd buffer size to at least 4KB.
546 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
549 /* our shared key (syslogd.c and logread.c must be in sync) */
550 enum { KEY_ID = 0x414e4547 }; /* "GENA" */
552 static void ipcsyslog_cleanup(void)
558 shmctl(G.shmid, IPC_RMID, NULL);
560 if (G.s_semid != -1) {
561 semctl(G.s_semid, 0, IPC_RMID, 0);
565 static void ipcsyslog_init(void)
568 printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
570 G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
572 bb_perror_msg_and_die("shmget");
575 G.shbuf = shmat(G.shmid, NULL, 0);
576 if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
577 bb_perror_msg_and_die("shmat");
580 memset(G.shbuf, 0, G.shm_size);
581 G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
582 /*G.shbuf->tail = 0;*/
584 /* we'll trust the OS to set initial semval to 0 (let's hope) */
585 G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
586 if (G.s_semid == -1) {
587 if (errno == EEXIST) {
588 G.s_semid = semget(KEY_ID, 2, 0);
592 bb_perror_msg_and_die("semget");
596 /* Write message to shared mem buffer */
597 static void log_to_shmem(const char *msg)
599 int old_tail, new_tail;
602 if (semop(G.s_semid, G.SMwdn, 3) == -1) {
603 bb_perror_msg_and_die("SMwdn");
606 /* Circular Buffer Algorithm:
607 * --------------------------
608 * tail == position where to store next syslog message.
609 * tail's max value is (shbuf->size - 1)
610 * Last byte of buffer is never used and remains NUL.
612 len = strlen(msg) + 1; /* length with NUL included */
614 old_tail = G.shbuf->tail;
615 new_tail = old_tail + len;
616 if (new_tail < G.shbuf->size) {
617 /* store message, set new tail */
618 memcpy(G.shbuf->data + old_tail, msg, len);
619 G.shbuf->tail = new_tail;
621 /* k == available buffer space ahead of old tail */
622 int k = G.shbuf->size - old_tail;
623 /* copy what fits to the end of buffer, and repeat */
624 memcpy(G.shbuf->data + old_tail, msg, k);
630 if (semop(G.s_semid, G.SMwup, 1) == -1) {
631 bb_perror_msg_and_die("SMwup");
634 printf("tail:%d\n", G.shbuf->tail);
637 static void ipcsyslog_cleanup(void) {}
638 static void ipcsyslog_init(void) {}
639 void log_to_shmem(const char *msg);
640 #endif /* FEATURE_IPC_SYSLOG */
642 #if ENABLE_FEATURE_KMSG_SYSLOG
643 static void kmsg_init(void)
645 G.kmsgfd = xopen("/dev/kmsg", O_WRONLY);
648 * kernel < 3.5 expects single char printk KERN_* priority prefix,
649 * from 3.5 onwards the full syslog facility/priority format is supported
651 if (get_linux_version_code() < KERNEL_VERSION(3,5,0))
652 G.primask = LOG_PRIMASK;
657 static void kmsg_cleanup(void)
659 if (ENABLE_FEATURE_CLEAN_UP)
663 /* Write message to /dev/kmsg */
664 static void log_to_kmsg(int pri, const char *msg)
667 * kernel < 3.5 expects single char printk KERN_* priority prefix,
668 * from 3.5 onwards the full syslog facility/priority format is supported
672 full_write(G.kmsgfd, G.printbuf, sprintf(G.printbuf, "<%d>%s\n", pri, msg));
675 static void kmsg_init(void) {}
676 static void kmsg_cleanup(void) {}
677 static void log_to_kmsg(int pri UNUSED_PARAM, const char *msg UNUSED_PARAM) {}
678 #endif /* FEATURE_KMSG_SYSLOG */
680 /* Print a message to the log file. */
681 static void log_locally(time_t now, char *msg, logFile_t *log_file)
683 #ifdef SYSLOGD_WRLOCK
686 int len = strlen(msg);
688 /* fd can't be 0 (we connect fd 0 to /dev/log socket) */
689 /* fd is 1 if "-O -" is in use */
690 if (log_file->fd > 1) {
691 /* Reopen log files every second. This allows admin
692 * to delete the files and not worry about restarting us.
693 * This costs almost nothing since it happens
694 * _at most_ once a second for each file, and happens
695 * only when each file is actually written.
699 if (log_file->last_log_time != now) {
700 log_file->last_log_time = now;
705 else if (log_file->fd == 1) {
706 /* We are logging to stdout: do nothing */
709 if (LONE_DASH(log_file->path)) {
711 /* log_file->isRegular = 0; - already is */
714 log_file->fd = open(log_file->path, O_WRONLY | O_CREAT
715 | O_NOCTTY | O_APPEND | O_NONBLOCK,
717 if (log_file->fd < 0) {
718 /* cannot open logfile? - print to /dev/console then */
719 int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
721 fd = 2; /* then stderr, dammit */
722 full_write(fd, msg, len);
727 #if ENABLE_FEATURE_ROTATE_LOGFILE
730 log_file->isRegular = (fstat(log_file->fd, &statf) == 0 && S_ISREG(statf.st_mode));
731 /* bug (mostly harmless): can wrap around if file > 4gb */
732 log_file->size = statf.st_size;
738 #ifdef SYSLOGD_WRLOCK
739 fl.l_whence = SEEK_SET;
743 fcntl(log_file->fd, F_SETLKW, &fl);
746 #if ENABLE_FEATURE_ROTATE_LOGFILE
747 if (G.logFileSize && log_file->isRegular && log_file->size > G.logFileSize) {
748 if (G.logFileRotate) { /* always 0..99 */
749 int i = strlen(log_file->path) + 3 + 1;
752 i = G.logFileRotate - 1;
753 /* rename: f.8 -> f.9; f.7 -> f.8; ... */
755 sprintf(newFile, "%s.%d", log_file->path, i);
757 sprintf(oldFile, "%s.%d", log_file->path, --i);
758 /* ignore errors - file might be missing */
759 rename(oldFile, newFile);
761 /* newFile == "f.0" now */
762 rename(log_file->path, newFile);
765 /* We may or may not have just renamed the file away;
766 * if we didn't rename because we aren't keeping any backlog,
767 * then it's time to clobber the file. If we did rename it...,
768 * incredibly, if F and F.0 are hardlinks, POSIX _demands_
769 * that rename returns 0 but does not remove F!!!
770 * (hardlinked F/F.0 pair was observed after
771 * power failure during rename()).
772 * So ensure old file is gone in any case:
774 unlink(log_file->path);
775 #ifdef SYSLOGD_WRLOCK
777 fcntl(log_file->fd, F_SETLKW, &fl);
782 /* TODO: what to do on write errors ("disk full")? */
783 len = full_write(log_file->fd, msg, len);
785 log_file->size += len;
787 full_write(log_file->fd, msg, len);
790 #ifdef SYSLOGD_WRLOCK
792 fcntl(log_file->fd, F_SETLKW, &fl);
796 static void parse_fac_prio_20(int pri, char *res20)
798 const CODE *c_pri, *c_fac;
800 c_fac = find_by_val(LOG_FAC(pri) << 3, facilitynames);
802 c_pri = find_by_val(LOG_PRI(pri), prioritynames);
804 snprintf(res20, 20, "%s.%s", c_fac->c_name, c_pri->c_name);
808 snprintf(res20, 20, "<%d>", pri);
811 /* len parameter is used only for "is there a timestamp?" check.
812 * NB: some callers cheat and supply len==0 when they know
813 * that there is no timestamp, short-circuiting the test. */
814 static void timestamp_and_log(int pri, char *msg, int len)
819 /* Jan 18 00:11:22 msg... */
820 /* 01234567890123456 */
821 if (len < 16 || msg[3] != ' ' || msg[6] != ' '
822 || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
825 timestamp = ctime(&now) + 4; /* skip day of week */
831 timestamp[15] = '\0';
833 if (option_mask32 & OPT_kmsg) {
834 log_to_kmsg(pri, msg);
838 if (option_mask32 & OPT_small)
839 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
842 parse_fac_prio_20(pri, res);
843 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
846 /* Log message locally (to file or shared mem) */
847 #if ENABLE_FEATURE_SYSLOGD_CFG
851 uint8_t facility = LOG_FAC(pri);
852 uint8_t prio_bit = 1 << LOG_PRI(pri);
854 for (rule = G.log_rules; rule; rule = rule->next) {
855 if (rule->enabled_facility_priomap[facility] & prio_bit) {
856 log_locally(now, G.printbuf, rule->file);
864 if (LOG_PRI(pri) < G.logLevel) {
865 #if ENABLE_FEATURE_IPC_SYSLOG
866 if ((option_mask32 & OPT_circularlog) && G.shbuf) {
867 log_to_shmem(G.printbuf);
871 log_locally(now, G.printbuf, &G.logFile);
875 static void timestamp_and_log_internal(const char *msg)
878 if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
880 timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
883 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
884 * embedded NULs. Split messages on each of these NULs, parse prio,
885 * escape control chars and log each locally. */
886 static void split_escape_and_log(char *tmpbuf, int len)
893 char *q = G.parsebuf;
894 int pri = (LOG_USER | LOG_NOTICE);
897 /* Parse the magic priority number */
898 pri = bb_strtou(p + 1, &p, 10);
901 if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
902 pri = (LOG_USER | LOG_NOTICE);
908 if (!(c & ~0x1f) && c != '\t') {
910 c += '@'; /* ^@, ^A, ^B... */
917 timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
922 static void do_mark(int sig)
924 if (G.markInterval) {
925 timestamp_and_log_internal("-- MARK --");
926 alarm(G.markInterval);
931 /* Don't inline: prevent struct sockaddr_un to take up space on stack
933 static NOINLINE int create_socket(void)
935 struct sockaddr_un sunx;
939 memset(&sunx, 0, sizeof(sunx));
940 sunx.sun_family = AF_UNIX;
942 /* Unlink old /dev/log or object it points to. */
943 /* (if it exists, bind will fail) */
944 strcpy(sunx.sun_path, _PATH_LOG);
945 dev_log_name = xmalloc_follow_symlinks(_PATH_LOG);
947 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
950 unlink(sunx.sun_path);
952 sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
953 xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
954 chmod(_PATH_LOG, 0666);
959 #if ENABLE_FEATURE_REMOTE_LOG
960 static int try_to_resolve_remote(remoteHost_t *rh)
962 if (!rh->remoteAddr) {
963 unsigned now = monotonic_sec();
965 /* Don't resolve name too often - DNS timeouts can be big */
966 if ((now - rh->last_dns_resolve) < DNS_WAIT_SEC)
968 rh->last_dns_resolve = now;
969 rh->remoteAddr = host2sockaddr(rh->remoteHostname, 514);
973 return xsocket(rh->remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
977 static void do_syslogd(void) NORETURN;
978 static void do_syslogd(void)
980 #if ENABLE_FEATURE_REMOTE_LOG
983 #if ENABLE_FEATURE_SYSLOGD_DUP
986 char *recvbuf = G.recvbuf;
988 #define recvbuf (G.recvbuf)
991 /* Set up signal handlers (so that they interrupt read()) */
992 signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo);
993 signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
994 //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo);
995 signal(SIGHUP, SIG_IGN);
997 signal(SIGALRM, do_mark);
998 alarm(G.markInterval);
1000 xmove_fd(create_socket(), STDIN_FILENO);
1002 if (option_mask32 & OPT_circularlog)
1005 if (option_mask32 & OPT_kmsg)
1008 timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
1010 while (!bb_got_signal) {
1013 #if ENABLE_FEATURE_SYSLOGD_DUP
1015 if (recvbuf == G.recvbuf)
1016 recvbuf = G.recvbuf + MAX_READ;
1018 recvbuf = G.recvbuf;
1021 sz = read(STDIN_FILENO, recvbuf, MAX_READ - 1);
1024 bb_perror_msg("read from %s", _PATH_LOG);
1028 /* Drop trailing '\n' and NULs (typically there is one NUL) */
1032 /* man 3 syslog says: "A trailing newline is added when needed".
1033 * However, neither glibc nor uclibc do this:
1034 * syslog(prio, "test") sends "test\0" to /dev/log,
1035 * syslog(prio, "test\n") sends "test\n\0".
1036 * IOW: newline is passed verbatim!
1037 * I take it to mean that it's syslogd's job
1038 * to make those look identical in the log files. */
1039 if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
1043 #if ENABLE_FEATURE_SYSLOGD_DUP
1044 if ((option_mask32 & OPT_dup) && (sz == last_sz))
1045 if (memcmp(last_buf, recvbuf, sz) == 0)
1049 #if ENABLE_FEATURE_REMOTE_LOG
1050 /* Stock syslogd sends it '\n'-terminated
1051 * over network, mimic that */
1054 /* We are not modifying log messages in any way before send */
1055 /* Remote site cannot trust _us_ anyway and need to do validation again */
1056 for (item = G.remoteHosts; item != NULL; item = item->link) {
1057 remoteHost_t *rh = (remoteHost_t *)item->data;
1059 if (rh->remoteFD == -1) {
1060 rh->remoteFD = try_to_resolve_remote(rh);
1061 if (rh->remoteFD == -1)
1065 /* Send message to remote logger.
1066 * On some errors, close and set remoteFD to -1
1067 * so that DNS resolution is retried.
1069 if (sendto(rh->remoteFD, recvbuf, sz+1,
1070 MSG_DONTWAIT | MSG_NOSIGNAL,
1071 &(rh->remoteAddr->u.sa), rh->remoteAddr->len) == -1
1075 case ENOTCONN: /* paranoia */
1077 close(rh->remoteFD);
1079 free(rh->remoteAddr);
1080 rh->remoteAddr = NULL;
1085 if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
1086 recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
1087 split_escape_and_log(recvbuf, sz);
1089 } /* while (!bb_got_signal) */
1091 timestamp_and_log_internal("syslogd exiting");
1092 remove_pidfile(CONFIG_PID_FILE_PATH "/syslogd.pid");
1093 ipcsyslog_cleanup();
1094 if (option_mask32 & OPT_kmsg)
1096 kill_myself_with_sig(bb_got_signal);
1100 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1101 int syslogd_main(int argc UNUSED_PARAM, char **argv)
1105 #if ENABLE_FEATURE_REMOTE_LOG
1106 llist_t *remoteAddrList = NULL;
1111 /* No non-option params, -R can occur multiple times */
1112 opt_complementary = "=0" IF_FEATURE_REMOTE_LOG(":R::");
1113 opts = getopt32(argv, OPTION_STR, OPTION_PARAM);
1114 #if ENABLE_FEATURE_REMOTE_LOG
1115 while (remoteAddrList) {
1116 remoteHost_t *rh = xzalloc(sizeof(*rh));
1117 rh->remoteHostname = llist_pop(&remoteAddrList);
1119 rh->last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
1120 llist_add_to(&G.remoteHosts, rh);
1125 if (opts & OPT_mark) // -m
1126 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
1128 //if (opts & OPT_nofork) // -n
1129 //if (opts & OPT_outfile) // -O
1130 if (opts & OPT_loglevel) // -l
1131 G.logLevel = xatou_range(opt_l, 1, 8);
1132 //if (opts & OPT_small) // -S
1133 #if ENABLE_FEATURE_ROTATE_LOGFILE
1134 if (opts & OPT_filesize) // -s
1135 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
1136 if (opts & OPT_rotatecnt) // -b
1137 G.logFileRotate = xatou_range(opt_b, 0, 99);
1139 #if ENABLE_FEATURE_IPC_SYSLOG
1141 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
1143 /* If they have not specified remote logging, then log locally */
1144 if (ENABLE_FEATURE_REMOTE_LOG && !(opts & OPT_remotelog)) // -R
1145 option_mask32 |= OPT_locallog;
1146 #if ENABLE_FEATURE_SYSLOGD_CFG
1147 parse_syslogdcfg(opt_f);
1150 /* Store away localhost's name before the fork */
1151 G.hostname = safe_gethostname();
1152 *strchrnul(G.hostname, '.') = '\0';
1154 if (!(opts & OPT_nofork)) {
1155 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
1159 write_pidfile(CONFIG_PID_FILE_PATH "/syslogd.pid");
1162 /* return EXIT_SUCCESS; */
1165 /* Clean up. Needed because we are included from syslogd_and_logger.c */
1168 #undef SYSLOGD_WRLOCK