/* vi: set sw=4 ts=4: */ /* * Mini syslogd implementation for busybox * * Copyright (C) 1999-2004 by Erik Andersen * * Copyright (C) 2000 by Karl M. Hegbloom * * "circular buffer" Copyright (C) 2001 by Gennady Feldman * * Maintainer: Gennady Feldman as of Mar 12, 2001 * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ /* * Done in syslogd_and_logger.c: #include "libbb.h" #define SYSLOG_NAMES #define SYSLOG_NAMES_CONST #include */ #include #include #if ENABLE_FEATURE_REMOTE_LOG #include #endif #if ENABLE_FEATURE_IPC_SYSLOG #include #include #include #endif #define DEBUG 0 /* MARK code is not very useful, is bloat, and broken: * can deadlock if alarmed to make MARK while writing to IPC buffer * (semaphores are down but do_mark routine tries to down them again) */ #undef SYSLOGD_MARK /* Write locking does not seem to be useful either */ #undef SYSLOGD_WRLOCK enum { MAX_READ = CONFIG_FEATURE_SYSLOGD_READ_BUFFER_SIZE, DNS_WAIT_SEC = 2 * 60, }; /* Semaphore operation structures */ struct shbuf_ds { int32_t size; /* size of data - 1 */ int32_t tail; /* end of message list */ char data[1]; /* data/messages */ }; #if ENABLE_FEATURE_REMOTE_LOG typedef struct { int remoteFD; unsigned last_dns_resolve; len_and_sockaddr *remoteAddr; const char *remoteHostname; } remoteHost_t; #endif /* Allows us to have smaller initializer. Ugly. */ #define GLOBALS \ const char *logFilePath; \ int logFD; \ /* interval between marks in seconds */ \ /*int markInterval;*/ \ /* level of messages to be logged */ \ int logLevel; \ IF_FEATURE_ROTATE_LOGFILE( \ /* max size of file before rotation */ \ unsigned logFileSize; \ /* number of rotated message files */ \ unsigned logFileRotate; \ unsigned curFileSize; \ smallint isRegular; \ ) \ IF_FEATURE_IPC_SYSLOG( \ int shmid; /* ipc shared memory id */ \ int s_semid; /* ipc semaphore id */ \ int shm_size; \ struct sembuf SMwup[1]; \ struct sembuf SMwdn[3]; \ ) struct init_globals { GLOBALS }; struct globals { GLOBALS #if ENABLE_FEATURE_REMOTE_LOG llist_t *remoteHosts; #endif #if ENABLE_FEATURE_IPC_SYSLOG struct shbuf_ds *shbuf; #endif time_t last_log_time; /* localhost's name. We print only first 64 chars */ char *hostname; /* We recv into recvbuf... */ char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)]; /* ...then copy to parsebuf, escaping control chars */ /* (can grow x2 max) */ char parsebuf[MAX_READ*2]; /* ...then sprintf into printbuf, adding timestamp (15 chars), * host (64), fac.prio (20) to the message */ /* (growth by: 15 + 64 + 20 + delims = ~110) */ char printbuf[MAX_READ*2 + 128]; }; static const struct init_globals init_data = { .logFilePath = "/var/log/messages", .logFD = -1, #ifdef SYSLOGD_MARK .markInterval = 20 * 60, #endif .logLevel = 8, #if ENABLE_FEATURE_ROTATE_LOGFILE .logFileSize = 200 * 1024, .logFileRotate = 1, #endif #if ENABLE_FEATURE_IPC_SYSLOG .shmid = -1, .s_semid = -1, .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), // default shm size .SMwup = { {1, -1, IPC_NOWAIT} }, .SMwdn = { {0, 0}, {1, 0}, {1, +1} }, #endif }; #define G (*ptr_to_globals) #define INIT_G() do { \ SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \ } while (0) /* Options */ enum { OPTBIT_mark = 0, // -m OPTBIT_nofork, // -n OPTBIT_outfile, // -O OPTBIT_loglevel, // -l OPTBIT_small, // -S IF_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize ,) // -s IF_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt ,) // -b IF_FEATURE_REMOTE_LOG( OPTBIT_remotelog ,) // -R IF_FEATURE_REMOTE_LOG( OPTBIT_locallog ,) // -L IF_FEATURE_IPC_SYSLOG( OPTBIT_circularlog,) // -C IF_FEATURE_SYSLOGD_DUP( OPTBIT_dup ,) // -D OPT_mark = 1 << OPTBIT_mark , OPT_nofork = 1 << OPTBIT_nofork , OPT_outfile = 1 << OPTBIT_outfile , OPT_loglevel = 1 << OPTBIT_loglevel, OPT_small = 1 << OPTBIT_small , OPT_filesize = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize )) + 0, OPT_rotatecnt = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt )) + 0, OPT_remotelog = IF_FEATURE_REMOTE_LOG( (1 << OPTBIT_remotelog )) + 0, OPT_locallog = IF_FEATURE_REMOTE_LOG( (1 << OPTBIT_locallog )) + 0, OPT_circularlog = IF_FEATURE_IPC_SYSLOG( (1 << OPTBIT_circularlog)) + 0, OPT_dup = IF_FEATURE_SYSLOGD_DUP( (1 << OPTBIT_dup )) + 0, }; #define OPTION_STR "m:nO:l:S" \ IF_FEATURE_ROTATE_LOGFILE("s:" ) \ IF_FEATURE_ROTATE_LOGFILE("b:" ) \ IF_FEATURE_REMOTE_LOG( "R:" ) \ IF_FEATURE_REMOTE_LOG( "L" ) \ IF_FEATURE_IPC_SYSLOG( "C::") \ IF_FEATURE_SYSLOGD_DUP( "D" ) #define OPTION_DECL *opt_m, *opt_l \ IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \ IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \ IF_FEATURE_IPC_SYSLOG( ,*opt_C = NULL) #define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \ IF_FEATURE_ROTATE_LOGFILE(,&opt_s) \ IF_FEATURE_ROTATE_LOGFILE(,&opt_b) \ IF_FEATURE_REMOTE_LOG( ,&remoteAddrList) \ IF_FEATURE_IPC_SYSLOG( ,&opt_C) /* circular buffer variables/structures */ #if ENABLE_FEATURE_IPC_SYSLOG #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4 #error Sorry, you must set the syslogd buffer size to at least 4KB. #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE #endif /* our shared key (syslogd.c and logread.c must be in sync) */ enum { KEY_ID = 0x414e4547 }; /* "GENA" */ static void ipcsyslog_cleanup(void) { if (G.shmid != -1) { shmdt(G.shbuf); } if (G.shmid != -1) { shmctl(G.shmid, IPC_RMID, NULL); } if (G.s_semid != -1) { semctl(G.s_semid, 0, IPC_RMID, 0); } } static void ipcsyslog_init(void) { if (DEBUG) printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size); G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644); if (G.shmid == -1) { bb_perror_msg_and_die("shmget"); } G.shbuf = shmat(G.shmid, NULL, 0); if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */ bb_perror_msg_and_die("shmat"); } memset(G.shbuf, 0, G.shm_size); G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1; /*G.shbuf->tail = 0;*/ // we'll trust the OS to set initial semval to 0 (let's hope) G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023); if (G.s_semid == -1) { if (errno == EEXIST) { G.s_semid = semget(KEY_ID, 2, 0); if (G.s_semid != -1) return; } bb_perror_msg_and_die("semget"); } } /* Write message to shared mem buffer */ static void log_to_shmem(const char *msg, int len) { int old_tail, new_tail; if (semop(G.s_semid, G.SMwdn, 3) == -1) { bb_perror_msg_and_die("SMwdn"); } /* Circular Buffer Algorithm: * -------------------------- * tail == position where to store next syslog message. * tail's max value is (shbuf->size - 1) * Last byte of buffer is never used and remains NUL. */ len++; /* length with NUL included */ again: old_tail = G.shbuf->tail; new_tail = old_tail + len; if (new_tail < G.shbuf->size) { /* store message, set new tail */ memcpy(G.shbuf->data + old_tail, msg, len); G.shbuf->tail = new_tail; } else { /* k == available buffer space ahead of old tail */ int k = G.shbuf->size - old_tail; /* copy what fits to the end of buffer, and repeat */ memcpy(G.shbuf->data + old_tail, msg, k); msg += k; len -= k; G.shbuf->tail = 0; goto again; } if (semop(G.s_semid, G.SMwup, 1) == -1) { bb_perror_msg_and_die("SMwup"); } if (DEBUG) printf("tail:%d\n", G.shbuf->tail); } #else void ipcsyslog_cleanup(void); void ipcsyslog_init(void); void log_to_shmem(const char *msg); #endif /* FEATURE_IPC_SYSLOG */ /* Print a message to the log file. */ static void log_locally(time_t now, char *msg) { #ifdef SYSLOGD_WRLOCK struct flock fl; #endif int len = strlen(msg); #if ENABLE_FEATURE_IPC_SYSLOG if ((option_mask32 & OPT_circularlog) && G.shbuf) { log_to_shmem(msg, len); return; } #endif if (G.logFD >= 0) { /* Reopen log file every second. This allows admin * to delete the file and not worry about restarting us. * This costs almost nothing since it happens * _at most_ once a second. */ if (!now) now = time(NULL); if (G.last_log_time != now) { G.last_log_time = now; close(G.logFD); goto reopen; } } else { reopen: G.logFD = open(G.logFilePath, O_WRONLY | O_CREAT | O_NOCTTY | O_APPEND | O_NONBLOCK, 0666); if (G.logFD < 0) { /* cannot open logfile? - print to /dev/console then */ int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK); if (fd < 0) fd = 2; /* then stderr, dammit */ full_write(fd, msg, len); if (fd != 2) close(fd); return; } #if ENABLE_FEATURE_ROTATE_LOGFILE { struct stat statf; G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode)); /* bug (mostly harmless): can wrap around if file > 4gb */ G.curFileSize = statf.st_size; } #endif } #ifdef SYSLOGD_WRLOCK fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 1; fl.l_type = F_WRLCK; fcntl(G.logFD, F_SETLKW, &fl); #endif #if ENABLE_FEATURE_ROTATE_LOGFILE if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) { if (G.logFileRotate) { /* always 0..99 */ int i = strlen(G.logFilePath) + 3 + 1; char oldFile[i]; char newFile[i]; i = G.logFileRotate - 1; /* rename: f.8 -> f.9; f.7 -> f.8; ... */ while (1) { sprintf(newFile, "%s.%d", G.logFilePath, i); if (i == 0) break; sprintf(oldFile, "%s.%d", G.logFilePath, --i); /* ignore errors - file might be missing */ rename(oldFile, newFile); } /* newFile == "f.0" now */ rename(G.logFilePath, newFile); #ifdef SYSLOGD_WRLOCK fl.l_type = F_UNLCK; fcntl(G.logFD, F_SETLKW, &fl); #endif close(G.logFD); goto reopen; } ftruncate(G.logFD, 0); } G.curFileSize += #endif full_write(G.logFD, msg, len); #ifdef SYSLOGD_WRLOCK fl.l_type = F_UNLCK; fcntl(G.logFD, F_SETLKW, &fl); #endif } static void parse_fac_prio_20(int pri, char *res20) { const CODE *c_pri, *c_fac; if (pri != 0) { c_fac = facilitynames; while (c_fac->c_name) { if (c_fac->c_val != (LOG_FAC(pri) << 3)) { c_fac++; continue; } /* facility is found, look for prio */ c_pri = prioritynames; while (c_pri->c_name) { if (c_pri->c_val != LOG_PRI(pri)) { c_pri++; continue; } snprintf(res20, 20, "%s.%s", c_fac->c_name, c_pri->c_name); return; } /* prio not found, bail out */ break; } snprintf(res20, 20, "<%d>", pri); } } /* len parameter is used only for "is there a timestamp?" check. * NB: some callers cheat and supply len==0 when they know * that there is no timestamp, short-circuiting the test. */ static void timestamp_and_log(int pri, char *msg, int len) { char *timestamp; time_t now; /* Jan 18 00:11:22 msg... */ /* 01234567890123456 */ if (len < 16 || msg[3] != ' ' || msg[6] != ' ' || msg[9] != ':' || msg[12] != ':' || msg[15] != ' ' ) { time(&now); timestamp = ctime(&now) + 4; /* skip day of week */ } else { now = 0; timestamp = msg; msg += 16; } timestamp[15] = '\0'; if (option_mask32 & OPT_small) sprintf(G.printbuf, "%s %s\n", timestamp, msg); else { char res[20]; parse_fac_prio_20(pri, res); sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg); } /* Log message locally (to file or shared mem) */ log_locally(now, G.printbuf); } static void timestamp_and_log_internal(const char *msg) { /* -L, or no -R */ if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog)) return; timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0); } /* tmpbuf[len] is a NUL byte (set by caller), but there can be other, * embedded NULs. Split messages on each of these NULs, parse prio, * escape control chars and log each locally. */ static void split_escape_and_log(char *tmpbuf, int len) { char *p = tmpbuf; tmpbuf += len; while (p < tmpbuf) { char c; char *q = G.parsebuf; int pri = (LOG_USER | LOG_NOTICE); if (*p == '<') { /* Parse the magic priority number */ pri = bb_strtou(p + 1, &p, 10); if (*p == '>') p++; if (pri & ~(LOG_FACMASK | LOG_PRIMASK)) pri = (LOG_USER | LOG_NOTICE); } while ((c = *p++)) { if (c == '\n') c = ' '; if (!(c & ~0x1f) && c != '\t') { *q++ = '^'; c += '@'; /* ^@, ^A, ^B... */ } *q++ = c; } *q = '\0'; /* Now log it */ if (LOG_PRI(pri) < G.logLevel) timestamp_and_log(pri, G.parsebuf, q - G.parsebuf); } } #ifdef SYSLOGD_MARK static void do_mark(int sig) { if (G.markInterval) { timestamp_and_log_internal("-- MARK --"); alarm(G.markInterval); } } #endif /* Don't inline: prevent struct sockaddr_un to take up space on stack * permanently */ static NOINLINE int create_socket(void) { struct sockaddr_un sunx; int sock_fd; char *dev_log_name; memset(&sunx, 0, sizeof(sunx)); sunx.sun_family = AF_UNIX; /* Unlink old /dev/log or object it points to. */ /* (if it exists, bind will fail) */ strcpy(sunx.sun_path, "/dev/log"); dev_log_name = xmalloc_follow_symlinks("/dev/log"); if (dev_log_name) { safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path)); free(dev_log_name); } unlink(sunx.sun_path); sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0); xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx)); chmod("/dev/log", 0666); return sock_fd; } #if ENABLE_FEATURE_REMOTE_LOG static int try_to_resolve_remote(remoteHost_t *rh) { if (!rh->remoteAddr) { unsigned now = monotonic_sec(); /* Don't resolve name too often - DNS timeouts can be big */ if ((now - rh->last_dns_resolve) < DNS_WAIT_SEC) return -1; rh->last_dns_resolve = now; rh->remoteAddr = host2sockaddr(rh->remoteHostname, 514); if (!rh->remoteAddr) return -1; } return xsocket(rh->remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0); } #endif static void do_syslogd(void) NORETURN; static void do_syslogd(void) { int sock_fd; #if ENABLE_FEATURE_REMOTE_LOG llist_t *item; #endif #if ENABLE_FEATURE_SYSLOGD_DUP int last_sz = -1; char *last_buf; char *recvbuf = G.recvbuf; #else #define recvbuf (G.recvbuf) #endif /* Set up signal handlers (so that they interrupt read()) */ signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo); signal_no_SA_RESTART_empty_mask(SIGINT, record_signo); //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo); signal(SIGHUP, SIG_IGN); #ifdef SYSLOGD_MARK signal(SIGALRM, do_mark); alarm(G.markInterval); #endif sock_fd = create_socket(); if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) { ipcsyslog_init(); } timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER); while (!bb_got_signal) { ssize_t sz; #if ENABLE_FEATURE_SYSLOGD_DUP last_buf = recvbuf; if (recvbuf == G.recvbuf) recvbuf = G.recvbuf + MAX_READ; else recvbuf = G.recvbuf; #endif read_again: sz = read(sock_fd, recvbuf, MAX_READ - 1); if (sz < 0) { if (!bb_got_signal) bb_perror_msg("read from /dev/log"); break; } /* Drop trailing '\n' and NULs (typically there is one NUL) */ while (1) { if (sz == 0) goto read_again; /* man 3 syslog says: "A trailing newline is added when needed". * However, neither glibc nor uclibc do this: * syslog(prio, "test") sends "test\0" to /dev/log, * syslog(prio, "test\n") sends "test\n\0". * IOW: newline is passed verbatim! * I take it to mean that it's syslogd's job * to make those look identical in the log files. */ if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n') break; sz--; } #if ENABLE_FEATURE_SYSLOGD_DUP if ((option_mask32 & OPT_dup) && (sz == last_sz)) if (memcmp(last_buf, recvbuf, sz) == 0) continue; last_sz = sz; #endif #if ENABLE_FEATURE_REMOTE_LOG /* Stock syslogd sends it '\n'-terminated * over network, mimic that */ recvbuf[sz] = '\n'; /* We are not modifying log messages in any way before send */ /* Remote site cannot trust _us_ anyway and need to do validation again */ for (item = G.remoteHosts; item != NULL; item = item->link) { remoteHost_t *rh = (remoteHost_t *)item->data; if (rh->remoteFD == -1) { rh->remoteFD = try_to_resolve_remote(rh); if (rh->remoteFD == -1) continue; } /* Send message to remote logger. * On some errors, close and set remoteFD to -1 * so that DNS resolution is retried. */ if (sendto(rh->remoteFD, recvbuf, sz+1, MSG_DONTWAIT | MSG_NOSIGNAL, &(rh->remoteAddr->u.sa), rh->remoteAddr->len) == -1 ) { switch (errno) { case ECONNRESET: case ENOTCONN: /* paranoia */ case EPIPE: close(rh->remoteFD); rh->remoteFD = -1; free(rh->remoteAddr); rh->remoteAddr = NULL; } } } #endif if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) { recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */ split_escape_and_log(recvbuf, sz); } } /* while (!bb_got_signal) */ timestamp_and_log_internal("syslogd exiting"); puts("syslogd exiting"); if (ENABLE_FEATURE_IPC_SYSLOG) ipcsyslog_cleanup(); kill_myself_with_sig(bb_got_signal); #undef recvbuf } int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int syslogd_main(int argc UNUSED_PARAM, char **argv) { int opts; char OPTION_DECL; #if ENABLE_FEATURE_REMOTE_LOG llist_t *remoteAddrList = NULL; #endif INIT_G(); /* No non-option params, -R can occur multiple times */ opt_complementary = "=0" IF_FEATURE_REMOTE_LOG(":R::"); opts = getopt32(argv, OPTION_STR, OPTION_PARAM); #if ENABLE_FEATURE_REMOTE_LOG while (remoteAddrList) { remoteHost_t *rh = xzalloc(sizeof(*rh)); rh->remoteHostname = llist_pop(&remoteAddrList); rh->remoteFD = -1; rh->last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1; llist_add_to(&G.remoteHosts, rh); } #endif #ifdef SYSLOGD_MARK if (opts & OPT_mark) // -m G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60; #endif //if (opts & OPT_nofork) // -n //if (opts & OPT_outfile) // -O if (opts & OPT_loglevel) // -l G.logLevel = xatou_range(opt_l, 1, 8); //if (opts & OPT_small) // -S #if ENABLE_FEATURE_ROTATE_LOGFILE if (opts & OPT_filesize) // -s G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024; if (opts & OPT_rotatecnt) // -b G.logFileRotate = xatou_range(opt_b, 0, 99); #endif #if ENABLE_FEATURE_IPC_SYSLOG if (opt_C) // -Cn G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024; #endif /* If they have not specified remote logging, then log locally */ if (ENABLE_FEATURE_REMOTE_LOG && !(opts & OPT_remotelog)) // -R option_mask32 |= OPT_locallog; /* Store away localhost's name before the fork */ G.hostname = safe_gethostname(); *strchrnul(G.hostname, '.') = '\0'; if (!(opts & OPT_nofork)) { bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv); } //umask(0); - why?? write_pidfile("/var/run/syslogd.pid"); do_syslogd(); /* return EXIT_SUCCESS; */ } /* Clean up. Needed because we are included from syslogd_and_logger.c */ #undef DEBUG #undef SYSLOGD_MARK #undef SYSLOGD_WRLOCK #undef G #undef GLOBALS #undef INIT_G #undef OPTION_STR #undef OPTION_DECL #undef OPTION_PARAM