release/src/router/busybox/sysklogd/syslogd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini syslogd implementation for busybox
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  *
   7  * Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
   8  *
   9  * "circular buffer" Copyright (C) 2001 by Gennady Feldman <gfeldman@gena01.com>
  10  *
  11  * Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
  12  *
  13  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  14  */
  15
  16 /*
  17  * Done in syslogd_and_logger.c:
  18 #include "libbb.h"
  19 #define SYSLOG_NAMES
  20 #define SYSLOG_NAMES_CONST
  21 #include <syslog.h>
  22 */
  23
  24 #include <paths.h>
  25 #include <sys/un.h>
  26 #include <sys/uio.h>
  27
  28 #if ENABLE_FEATURE_REMOTE_LOG
  29 #include <netinet/in.h>
  30 #endif
  31
  32 #if ENABLE_FEATURE_IPC_SYSLOG
  33 #include <sys/ipc.h>
  34 #include <sys/sem.h>
  35 #include <sys/shm.h>
  36 #endif
  37
  38
  39 #define DEBUG 0
  40
  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) */
  44 #undef SYSLOGD_MARK
  45
  46 /* Write locking does not seem to be useful either */
  47 #undef SYSLOGD_WRLOCK
  48
  49 enum {
  50         MAX_READ = 256,
  51         DNS_WAIT_SEC = 2 * 60,
  52 };
  53
  54 /* Semaphore operation structures */
  55 struct shbuf_ds {
  56         int32_t size;   /* size of data - 1 */
  57         int32_t tail;   /* end of message list */
  58         char data[1];   /* data/messages */
  59 };
  60
  61 /* Allows us to have smaller initializer. Ugly. */
  62 #define GLOBALS \
  63         const char *logFilePath;                \
  64         int logFD;                              \
  65         /* interval between marks in seconds */ \
  66         /*int markInterval;*/                   \
  67         /* level of messages to be logged */    \
  68         int logLevel;                           \
  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;                   \
  75         smallint isRegular;                     \
  76 ) \
  77 USE_FEATURE_REMOTE_LOG( \
  78         /* udp socket for remote logging */     \
  79         int remoteFD;                           \
  80         len_and_sockaddr* remoteAddr;           \
  81 ) \
  82 USE_FEATURE_IPC_SYSLOG( \
  83         int shmid; /* ipc shared memory id */   \
  84         int s_semid; /* ipc semaphore id */     \
  85         int shm_size;                           \
  86         struct sembuf SMwup[1];                 \
  87         struct sembuf SMwdn[3];                 \
  88 )
  89
  90 struct init_globals {
  91         GLOBALS
  92 };
  93
  94 struct globals {
  95         GLOBALS
  96
  97 #if ENABLE_FEATURE_REMOTE_LOG
  98         unsigned last_dns_resolve;
  99         char *remoteAddrStr;
 100 #endif
 101
 102 #if ENABLE_FEATURE_IPC_SYSLOG
 103         struct shbuf_ds *shbuf;
 104 #endif
 105         time_t last_log_time;
 106         /* localhost's name. We print only first 64 chars */
 107         char *hostname;
 108
 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];
 118 };
 119
 120 static const struct init_globals init_data = {
 121         .logFilePath = "/var/log/messages",
 122         .logFD = -1,
 123 #ifdef SYSLOGD_MARK
 124         .markInterval = 20 * 60,
 125 #endif
 126         .logLevel = 8,
 127 #if ENABLE_FEATURE_ROTATE_LOGFILE
 128         .logFileSize = 200 * 1024,
 129         .logFileRotate = 1,
 130 #endif
 131 #if ENABLE_FEATURE_REMOTE_LOG
 132         .remoteFD = -1,
 133 #endif
 134 #if ENABLE_FEATURE_IPC_SYSLOG
 135         .shmid = -1,
 136         .s_semid = -1,
 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} },
 140 #endif
 141 };
 142
 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))); \
 146 } while (0)
 147
 148
 149 /* Options */
 150 enum {
 151         OPTBIT_mark = 0, // -m
 152         OPTBIT_nofork, // -n
 153         OPTBIT_outfile, // -O
 154         OPTBIT_loglevel, // -l
 155         OPTBIT_small, // -S
 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
 162
 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,
 174 };
 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)
 191
 192
 193 /* circular buffer variables/structures */
 194 #if ENABLE_FEATURE_IPC_SYSLOG
 195
 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
 199 #endif
 200
 201 /* our shared key (syslogd.c and logread.c must be in sync) */
 202 enum { KEY_ID = 0x414e4547 }; /* "GENA" */
 203
 204 static void ipcsyslog_cleanup(void)
 205 {
 206         if (G.shmid != -1) {
 207                 shmdt(G.shbuf);
 208         }
 209         if (G.shmid != -1) {
 210                 shmctl(G.shmid, IPC_RMID, NULL);
 211         }
 212         if (G.s_semid != -1) {
 213                 semctl(G.s_semid, 0, IPC_RMID, 0);
 214         }
 215 }
 216
 217 static void ipcsyslog_init(void)
 218 {
 219         if (DEBUG)
 220                 printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
 221
 222         G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
 223         if (G.shmid == -1) {
 224                 bb_perror_msg_and_die("shmget");
 225         }
 226
 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");
 230         }
 231
 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;*/
 235
 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);
 241                         if (G.s_semid != -1)
 242                                 return;
 243                 }
 244                 bb_perror_msg_and_die("semget");
 245         }
 246 }
 247
 248 /* Write message to shared mem buffer */
 249 static void log_to_shmem(const char *msg, int len)
 250 {
 251         int old_tail, new_tail;
 252
 253         if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 254                 bb_perror_msg_and_die("SMwdn");
 255         }
 256
 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.
 262          */
 263         len++; /* length with NUL included */
 264  again:
 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;
 271         } else {
 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);
 276                 msg += k;
 277                 len -= k;
 278                 G.shbuf->tail = 0;
 279                 goto again;
 280         }
 281         if (semop(G.s_semid, G.SMwup, 1) == -1) {
 282                 bb_perror_msg_and_die("SMwup");
 283         }
 284         if (DEBUG)
 285                 printf("tail:%d\n", G.shbuf->tail);
 286 }
 287 #else
 288 void ipcsyslog_cleanup(void);
 289 void ipcsyslog_init(void);
 290 void log_to_shmem(const char *msg);
 291 #endif /* FEATURE_IPC_SYSLOG */
 292
 293
 294 /* Print a message to the log file. */
 295 static void log_locally(time_t now, char *msg)
 296 {
 297 #ifdef SYSLOGD_WRLOCK
 298         struct flock fl;
 299 #endif
 300         int len = strlen(msg);
 301
 302 #if ENABLE_FEATURE_IPC_SYSLOG
 303         if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 304                 log_to_shmem(msg, len);
 305                 return;
 306         }
 307 #endif
 308         if (G.logFD >= 0) {
 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.
 313                  */
 314                 if (!now)
 315                         now = time(NULL);
 316                 if (G.last_log_time != now) {
 317                         G.last_log_time = now;
 318                         close(G.logFD);
 319                         goto reopen;
 320                 }
 321         } else {
 322  reopen:
 323                 G.logFD = open(G.logFilePath, O_WRONLY | O_CREAT
 324                                         | O_NOCTTY | O_APPEND | O_NONBLOCK,
 325                                         0666);
 326                 if (G.logFD < 0) {
 327                         /* cannot open logfile? - print to /dev/console then */
 328                         int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
 329                         if (fd < 0)
 330                                 fd = 2; /* then stderr, dammit */
 331                         full_write(fd, msg, len);
 332                         if (fd != 2)
 333                                 close(fd);
 334                         return;
 335                 }
 336 #if ENABLE_FEATURE_ROTATE_LOGFILE
 337                 {
 338                         struct stat statf;
 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;
 342                 }
 343 #endif
 344         }
 345
 346 #ifdef SYSLOGD_WRLOCK
 347         fl.l_whence = SEEK_SET;
 348         fl.l_start = 0;
 349         fl.l_len = 1;
 350         fl.l_type = F_WRLCK;
 351         fcntl(G.logFD, F_SETLKW, &fl);
 352 #endif
 353
 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;
 358                         char oldFile[i];
 359                         char newFile[i];
 360                         i = G.logFileRotate - 1;
 361                         /* rename: f.8 -> f.9; f.7 -> f.8; ... */
 362                         while (1) {
 363                                 sprintf(newFile, "%s.%d", G.logFilePath, i);
 364                                 if (i == 0) break;
 365                                 sprintf(oldFile, "%s.%d", G.logFilePath, --i);
 366                                 /* ignore errors - file might be missing */
 367                                 rename(oldFile, newFile);
 368                         }
 369                         /* newFile == "f.0" now */
 370                         rename(G.logFilePath, newFile);
 371 #ifdef SYSLOGD_WRLOCK
 372                         fl.l_type = F_UNLCK;
 373                         fcntl(G.logFD, F_SETLKW, &fl);
 374 #endif
 375                         close(G.logFD);
 376                         goto reopen;
 377                 }
 378                 ftruncate(G.logFD, 0);
 379         }
 380         G.curFileSize +=
 381 #endif
 382                         full_write(G.logFD, msg, len);
 383 #ifdef SYSLOGD_WRLOCK
 384         fl.l_type = F_UNLCK;
 385         fcntl(G.logFD, F_SETLKW, &fl);
 386 #endif
 387 }
 388
 389 static void parse_fac_prio_20(int pri, char *res20)
 390 {
 391         const CODE *c_pri, *c_fac;
 392
 393         if (pri != 0) {
 394                 c_fac = facilitynames;
 395                 while (c_fac->c_name) {
 396                         if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
 397                                 c_fac++;
 398                                 continue;
 399                         }
 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)) {
 404                                         c_pri++;
 405                                         continue;
 406                                 }
 407                                 snprintf(res20, 20, "%s.%s",
 408                                                 c_fac->c_name, c_pri->c_name);
 409                                 return;
 410                         }
 411                         /* prio not found, bail out */
 412                         break;
 413                 }
 414                 snprintf(res20, 20, "<%d>", pri);
 415         }
 416 }
 417
 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)
 422 {
 423         char *timestamp;
 424         time_t now;
 425
 426         if (len < 16 || msg[3] != ' ' || msg[6] != ' '
 427          || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
 428         ) {
 429                 time(&now);
 430                 timestamp = ctime(&now) + 4; /* skip day of week */
 431         } else {
 432                 now = 0;
 433                 timestamp = msg;
 434                 msg += 16;
 435         }
 436         timestamp[15] = '\0';
 437
 438         if (option_mask32 & OPT_small)
 439                 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
 440         else {
 441                 char res[20];
 442                 parse_fac_prio_20(pri, res);
 443                 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
 444         }
 445
 446         /* Log message locally (to file or shared mem) */
 447         log_locally(now, G.printbuf);
 448 }
 449
 450 static void timestamp_and_log_internal(const char *msg)
 451 {
 452         /* -L, or no -R */
 453         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
 454                 return;
 455         timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
 456 }
 457
 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)
 462 {
 463         char *p = tmpbuf;
 464
 465         tmpbuf += len;
 466         while (p < tmpbuf) {
 467                 char c;
 468                 char *q = G.parsebuf;
 469                 int pri = (LOG_USER | LOG_NOTICE);
 470
 471                 if (*p == '<') {
 472                         /* Parse the magic priority number */
 473                         pri = bb_strtou(p + 1, &p, 10);
 474                         if (*p == '>')
 475                                 p++;
 476                         if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 477                                 pri = (LOG_USER | LOG_NOTICE);
 478                 }
 479
 480                 while ((c = *p++)) {
 481                         if (c == '\n')
 482                                 c = ' ';
 483                         if (!(c & ~0x1f) && c != '\t') {
 484                                 *q++ = '^';
 485                                 c += '@'; /* ^@, ^A, ^B... */
 486                         }
 487                         *q++ = c;
 488                 }
 489                 *q = '\0';
 490
 491                 /* Now log it */
 492                 if (LOG_PRI(pri) < G.logLevel)
 493                         timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
 494         }
 495 }
 496
 497 #ifdef SYSLOGD_MARK
 498 static void do_mark(int sig)
 499 {
 500         if (G.markInterval) {
 501                 timestamp_and_log_internal("-- MARK --");
 502                 alarm(G.markInterval);
 503         }
 504 }
 505 #endif
 506
 507 /* Don't inline: prevent struct sockaddr_un to take up space on stack
 508  * permanently */
 509 static NOINLINE int create_socket(void)
 510 {
 511         struct sockaddr_un sunx;
 512         int sock_fd;
 513         char *dev_log_name;
 514
 515         memset(&sunx, 0, sizeof(sunx));
 516         sunx.sun_family = AF_UNIX;
 517
 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");
 522         if (dev_log_name) {
 523                 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
 524                 free(dev_log_name);
 525         }
 526         unlink(sunx.sun_path);
 527
 528         sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
 529         xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
 530         chmod("/dev/log", 0666);
 531
 532         return sock_fd;
 533 }
 534
 535 #if ENABLE_FEATURE_REMOTE_LOG
 536 static int try_to_resolve_remote(void)
 537 {
 538         if (!G.remoteAddr) {
 539                 unsigned now = monotonic_sec();
 540
 541                 /* Don't resolve name too often - DNS timeouts can be big */
 542                 if ((now - G.last_dns_resolve) < DNS_WAIT_SEC)
 543                         return -1;
 544                 G.last_dns_resolve = now;
 545                 G.remoteAddr = host2sockaddr(G.remoteAddrStr, 514);
 546                 if (!G.remoteAddr)
 547                         return -1;
 548         }
 549         return socket(G.remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
 550 }
 551 #endif
 552
 553 static void do_syslogd(void) NORETURN;
 554 static void do_syslogd(void)
 555 {
 556         int sock_fd;
 557 #if ENABLE_FEATURE_SYSLOGD_DUP
 558         int last_sz = -1;
 559         char *last_buf;
 560         char *recvbuf = G.recvbuf;
 561 #else
 562 #define recvbuf (G.recvbuf)
 563 #endif
 564
 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);
 570 #ifdef SYSLOGD_MARK
 571         signal(SIGALRM, do_mark);
 572         alarm(G.markInterval);
 573 #endif
 574         sock_fd = create_socket();
 575
 576         if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
 577                 ipcsyslog_init();
 578         }
 579
 580         timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
 581
 582         while (!bb_got_signal) {
 583                 ssize_t sz;
 584
 585 #if ENABLE_FEATURE_SYSLOGD_DUP
 586                 last_buf = recvbuf;
 587                 if (recvbuf == G.recvbuf)
 588                         recvbuf = G.recvbuf + MAX_READ;
 589                 else
 590                         recvbuf = G.recvbuf;
 591 #endif
 592  read_again:
 593                 sz = read(sock_fd, recvbuf, MAX_READ - 1);
 594                 if (sz < 0) {
 595                         if (!bb_got_signal)
 596                                 bb_perror_msg("read from /dev/log");
 597                         break;
 598                 }
 599
 600                 /* Drop trailing '\n' and NULs (typically there is one NUL) */
 601                 while (1) {
 602                         if (sz == 0)
 603                                 goto read_again;
 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')
 612                                 break;
 613                         sz--;
 614                 }
 615 #if ENABLE_FEATURE_SYSLOGD_DUP
 616                 if ((option_mask32 & OPT_dup) && (sz == last_sz))
 617                         if (memcmp(last_buf, recvbuf, sz) == 0)
 618                                 continue;
 619                 last_sz = sz;
 620 #endif
 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)
 628                                         goto no_luck;
 629                         }
 630                         /* Stock syslogd sends it '\n'-terminated
 631                          * over network, mimic that */
 632                         recvbuf[sz] = '\n';
 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);
 638  no_luck: ;
 639                 }
 640 #endif
 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);
 644                 }
 645         } /* while (!bb_got_signal) */
 646
 647         timestamp_and_log_internal("syslogd exiting");
 648         puts("syslogd exiting");
 649         if (ENABLE_FEATURE_IPC_SYSLOG)
 650                 ipcsyslog_cleanup();
 651         kill_myself_with_sig(bb_got_signal);
 652 #undef recvbuf
 653 }
 654
 655 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 656 int syslogd_main(int argc UNUSED_PARAM, char **argv)
 657 {
 658         char OPTION_DECL;
 659         int opts;
 660
 661         INIT_G();
 662 #if ENABLE_FEATURE_REMOTE_LOG
 663         G.last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
 664 #endif
 665
 666         /* do normal option parsing */
 667         opt_complementary = "=0"; /* no non-option params */
 668         opts = getopt32(argv, OPTION_STR, OPTION_PARAM);
 669 #ifdef SYSLOGD_MARK
 670         if (opts & OPT_mark) // -m
 671                 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
 672 #endif
 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);
 683 #endif
 684 #if ENABLE_FEATURE_IPC_SYSLOG
 685         if (opt_C) // -Cn
 686                 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
 687 #endif
 688
 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;
 692
 693         /* Store away localhost's name before the fork */
 694         G.hostname = safe_gethostname();
 695         *strchrnul(G.hostname, '.') = '\0';
 696
 697         if (!(opts & OPT_nofork)) {
 698                 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
 699         }
 700         umask(0);
 701         write_pidfile("/var/run/syslogd.pid");
 702         do_syslogd();
 703         /* return EXIT_SUCCESS; */
 704 }
 705
 706 /* Clean up. Needed because we are included from syslogd_and_logger.c */
 707 #undef DEBUG
 708 #undef SYSLOGD_MARK
 709 #undef SYSLOGD_WRLOCK
 710 #undef G
 711 #undef GLOBALS
 712 #undef INIT_G
 713 #undef OPTION_STR
 714 #undef OPTION_DECL
 715 #undef OPTION_PARAM