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 #include "libbb.h"
  17 #include <paths.h>
  18 #include <sys/un.h>
  19
  20 /* SYSLOG_NAMES defined to pull prioritynames[] and facilitynames[]
  21  * from syslog.h. Grrrr - glibc puts those in _rwdata_! :( */
  22 #define SYSLOG_NAMES
  23 #define SYSLOG_NAMES_CONST /* uclibc is saner :) */
  24 #include <sys/syslog.h>
  25 #include <sys/uio.h>
  26
  27 #if ENABLE_FEATURE_REMOTE_LOG
  28 #include <netinet/in.h>
  29 #endif
  30
  31 #if ENABLE_FEATURE_IPC_SYSLOG
  32 #include <sys/ipc.h>
  33 #include <sys/sem.h>
  34 #include <sys/shm.h>
  35 #endif
  36
  37
  38 #define DEBUG 0
  39
  40 /* MARK code is not very useful, is bloat, and broken:
  41  * can deadlock if alarmed to make MARK while writing to IPC buffer
  42  * (semaphores are down but do_mark routine tries to down them again) */
  43 #undef SYSLOGD_MARK
  44
  45 enum { MAX_READ = 256 };
  46
  47 /* Semaphore operation structures */
  48 struct shbuf_ds {
  49         int32_t size;   /* size of data - 1 */
  50         int32_t tail;   /* end of message list */
  51         char data[1];   /* data/messages */
  52 };
  53
  54 /* Allows us to have smaller initializer. Ugly. */
  55 #define GLOBALS \
  56         const char *logFilePath;                \
  57         int logFD;                              \
  58         /* interval between marks in seconds */ \
  59         /*int markInterval;*/                   \
  60         /* level of messages to be logged */    \
  61         int logLevel;                           \
  62 USE_FEATURE_ROTATE_LOGFILE( \
  63         /* max size of file before rotation */  \
  64         unsigned logFileSize;                   \
  65         /* number of rotated message files */   \
  66         unsigned logFileRotate;                 \
  67         unsigned curFileSize;                   \
  68         smallint isRegular;                     \
  69 ) \
  70 USE_FEATURE_REMOTE_LOG( \
  71         /* udp socket for remote logging */     \
  72         int remoteFD;                           \
  73         len_and_sockaddr* remoteAddr;           \
  74 ) \
  75 USE_FEATURE_IPC_SYSLOG( \
  76         int shmid; /* ipc shared memory id */   \
  77         int s_semid; /* ipc semaphore id */     \
  78         int shm_size;                           \
  79         struct sembuf SMwup[1];                 \
  80         struct sembuf SMwdn[3];                 \
  81 )
  82
  83 struct init_globals {
  84         GLOBALS
  85 };
  86
  87 struct globals {
  88         GLOBALS
  89 #if ENABLE_FEATURE_IPC_SYSLOG
  90         struct shbuf_ds *shbuf;
  91 #endif
  92         time_t last_log_time;
  93         /* localhost's name */
  94         char localHostName[64];
  95
  96         /* We recv into recvbuf... */
  97         char recvbuf[MAX_READ];
  98         /* ...then copy to parsebuf, escaping control chars */
  99         /* (can grow x2 max) */
 100         char parsebuf[MAX_READ*2];
 101         /* ...then sprintf into printbuf, adding timestamp (15 chars),
 102          * host (64), fac.prio (20) to the message */
 103         /* (growth by: 15 + 64 + 20 + delims = ~110) */
 104         char printbuf[MAX_READ*2 + 128];
 105 };
 106
 107 static const struct init_globals init_data = {
 108         .logFilePath = "/var/log/messages",
 109         .logFD = -1,
 110 #ifdef SYSLOGD_MARK
 111         .markInterval = 20 * 60,
 112 #endif
 113         .logLevel = 8,
 114 #if ENABLE_FEATURE_ROTATE_LOGFILE
 115         .logFileSize = 200 * 1024,
 116         .logFileRotate = 1,
 117 #endif
 118 #if ENABLE_FEATURE_REMOTE_LOG
 119         .remoteFD = -1,
 120 #endif
 121 #if ENABLE_FEATURE_IPC_SYSLOG
 122         .shmid = -1,
 123         .s_semid = -1,
 124         .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), // default shm size
 125         .SMwup = { {1, -1, IPC_NOWAIT} },
 126         .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
 127 #endif
 128 };
 129
 130 #define G (*ptr_to_globals)
 131
 132
 133 /* Options */
 134 enum {
 135         OPTBIT_mark = 0, // -m
 136         OPTBIT_nofork, // -n
 137         OPTBIT_outfile, // -O
 138         OPTBIT_loglevel, // -l
 139         OPTBIT_small, // -S
 140         USE_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,) // -s
 141         USE_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,) // -b
 142         USE_FEATURE_REMOTE_LOG(    OPTBIT_remote     ,) // -R
 143         USE_FEATURE_REMOTE_LOG(    OPTBIT_localtoo   ,) // -L
 144         USE_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,) // -C
 145
 146         OPT_mark        = 1 << OPTBIT_mark    ,
 147         OPT_nofork      = 1 << OPTBIT_nofork  ,
 148         OPT_outfile     = 1 << OPTBIT_outfile ,
 149         OPT_loglevel    = 1 << OPTBIT_loglevel,
 150         OPT_small       = 1 << OPTBIT_small   ,
 151         OPT_filesize    = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
 152         OPT_rotatecnt   = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
 153         OPT_remotelog   = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remote     )) + 0,
 154         OPT_locallog    = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_localtoo   )) + 0,
 155         OPT_circularlog = USE_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
 156 };
 157 #define OPTION_STR "m:nO:l:S" \
 158         USE_FEATURE_ROTATE_LOGFILE("s:" ) \
 159         USE_FEATURE_ROTATE_LOGFILE("b:" ) \
 160         USE_FEATURE_REMOTE_LOG(    "R:" ) \
 161         USE_FEATURE_REMOTE_LOG(    "L"  ) \
 162         USE_FEATURE_IPC_SYSLOG(    "C::")
 163 #define OPTION_DECL *opt_m, *opt_l \
 164         USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
 165         USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
 166         USE_FEATURE_REMOTE_LOG(    ,*opt_R) \
 167         USE_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL)
 168 #define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \
 169         USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
 170         USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
 171         USE_FEATURE_REMOTE_LOG(    ,&opt_R) \
 172         USE_FEATURE_IPC_SYSLOG(    ,&opt_C)
 173
 174
 175 /* circular buffer variables/structures */
 176 #if ENABLE_FEATURE_IPC_SYSLOG
 177
 178 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
 179 #error Sorry, you must set the syslogd buffer size to at least 4KB.
 180 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 181 #endif
 182
 183 /* our shared key */
 184 #define KEY_ID ((long)0x414e4547) /* "GENA" */
 185
 186 static void ipcsyslog_cleanup(void)
 187 {
 188         if (G.shmid != -1) {
 189                 shmdt(G.shbuf);
 190         }
 191         if (G.shmid != -1) {
 192                 shmctl(G.shmid, IPC_RMID, NULL);
 193         }
 194         if (G.s_semid != -1) {
 195                 semctl(G.s_semid, 0, IPC_RMID, 0);
 196         }
 197 }
 198
 199 static void ipcsyslog_init(void)
 200 {
 201         if (DEBUG)
 202                 printf("shmget(%lx, %d,...)\n", KEY_ID, G.shm_size);
 203
 204         G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 1023);
 205         if (G.shmid == -1) {
 206                 bb_perror_msg_and_die("shmget");
 207         }
 208
 209         G.shbuf = shmat(G.shmid, NULL, 0);
 210         if (!G.shbuf) {
 211                 bb_perror_msg_and_die("shmat");
 212         }
 213
 214         memset(G.shbuf, 0, G.shm_size);
 215         G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
 216         /*G.shbuf->tail = 0;*/
 217
 218         // we'll trust the OS to set initial semval to 0 (let's hope)
 219         G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
 220         if (G.s_semid == -1) {
 221                 if (errno == EEXIST) {
 222                         G.s_semid = semget(KEY_ID, 2, 0);
 223                         if (G.s_semid != -1)
 224                                 return;
 225                 }
 226                 bb_perror_msg_and_die("semget");
 227         }
 228 }
 229
 230 /* Write message to shared mem buffer */
 231 static void log_to_shmem(const char *msg, int len)
 232 {
 233         int old_tail, new_tail;
 234
 235         if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 236                 bb_perror_msg_and_die("SMwdn");
 237         }
 238
 239         /* Circular Buffer Algorithm:
 240          * --------------------------
 241          * tail == position where to store next syslog message.
 242          * tail's max value is (shbuf->size - 1)
 243          * Last byte of buffer is never used and remains NUL.
 244          */
 245         len++; /* length with NUL included */
 246  again:
 247         old_tail = G.shbuf->tail;
 248         new_tail = old_tail + len;
 249         if (new_tail < G.shbuf->size) {
 250                 /* store message, set new tail */
 251                 memcpy(G.shbuf->data + old_tail, msg, len);
 252                 G.shbuf->tail = new_tail;
 253         } else {
 254                 /* k == available buffer space ahead of old tail */
 255                 int k = G.shbuf->size - old_tail;
 256                 /* copy what fits to the end of buffer, and repeat */
 257                 memcpy(G.shbuf->data + old_tail, msg, k);
 258                 msg += k;
 259                 len -= k;
 260                 G.shbuf->tail = 0;
 261                 goto again;
 262         }
 263         if (semop(G.s_semid, G.SMwup, 1) == -1) {
 264                 bb_perror_msg_and_die("SMwup");
 265         }
 266         if (DEBUG)
 267                 printf("tail:%d\n", G.shbuf->tail);
 268 }
 269 #else
 270 void ipcsyslog_cleanup(void);
 271 void ipcsyslog_init(void);
 272 void log_to_shmem(const char *msg);
 273 #endif /* FEATURE_IPC_SYSLOG */
 274
 275
 276 /* Print a message to the log file. */
 277 static void log_locally(char *msg)
 278 {
 279         struct flock fl;
 280         int len = strlen(msg);
 281
 282 #if ENABLE_FEATURE_IPC_SYSLOG
 283         if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 284                 log_to_shmem(msg, len);
 285                 return;
 286         }
 287 #endif
 288         if (G.logFD >= 0) {
 289                 time_t cur;
 290                 time(&cur);
 291                 if (G.last_log_time != cur) {
 292                         G.last_log_time = cur; /* reopen log file every second */
 293                         close(G.logFD);
 294                         goto reopen;
 295                 }
 296         } else {
 297  reopen:
 298                 G.logFD = device_open(G.logFilePath, O_WRONLY | O_CREAT
 299                                         | O_NOCTTY | O_APPEND | O_NONBLOCK);
 300                 if (G.logFD < 0) {
 301                         /* cannot open logfile? - print to /dev/console then */
 302                         int fd = device_open(_PATH_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
 303                         if (fd < 0)
 304                                 fd = 2; /* then stderr, dammit */
 305                         full_write(fd, msg, len);
 306                         if (fd != 2)
 307                                 close(fd);
 308                         return;
 309                 }
 310 #if ENABLE_FEATURE_ROTATE_LOGFILE
 311                 {
 312                         struct stat statf;
 313                         G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode));
 314                         /* bug (mostly harmless): can wrap around if file > 4gb */
 315                         G.curFileSize = statf.st_size;
 316                 }
 317 #endif
 318         }
 319
 320         fl.l_whence = SEEK_SET;
 321         fl.l_start = 0;
 322         fl.l_len = 1;
 323         fl.l_type = F_WRLCK;
 324         fcntl(G.logFD, F_SETLKW, &fl);
 325
 326 #if ENABLE_FEATURE_ROTATE_LOGFILE
 327         if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) {
 328                 if (G.logFileRotate) { /* always 0..99 */
 329                         int i = strlen(G.logFilePath) + 3 + 1;
 330                         char oldFile[i];
 331                         char newFile[i];
 332                         i = G.logFileRotate - 1;
 333                         /* rename: f.8 -> f.9; f.7 -> f.8; ... */
 334                         while (1) {
 335                                 sprintf(newFile, "%s.%d", G.logFilePath, i);
 336                                 if (i == 0) break;
 337                                 sprintf(oldFile, "%s.%d", G.logFilePath, --i);
 338                                 rename(oldFile, newFile);
 339                         }
 340                         /* newFile == "f.0" now */
 341                         rename(G.logFilePath, newFile);
 342                         fl.l_type = F_UNLCK;
 343                         fcntl(G.logFD, F_SETLKW, &fl);
 344                         close(G.logFD);
 345                         goto reopen;
 346                 }
 347                 ftruncate(G.logFD, 0);
 348         }
 349         G.curFileSize +=
 350 #endif
 351                         full_write(G.logFD, msg, len);
 352         fl.l_type = F_UNLCK;
 353         fcntl(G.logFD, F_SETLKW, &fl);
 354 }
 355
 356 static void parse_fac_prio_20(int pri, char *res20)
 357 {
 358         const CODE *c_pri, *c_fac;
 359
 360         if (pri != 0) {
 361                 c_fac = facilitynames;
 362                 while (c_fac->c_name) {
 363                         if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
 364                                 c_fac++; continue;
 365                         }
 366                         /* facility is found, look for prio */
 367                         c_pri = prioritynames;
 368                         while (c_pri->c_name) {
 369                                 if (c_pri->c_val != LOG_PRI(pri)) {
 370                                         c_pri++; continue;
 371                                 }
 372                                 snprintf(res20, 20, "%s.%s",
 373                                                 c_fac->c_name, c_pri->c_name);
 374                                 return;
 375                         }
 376                         /* prio not found, bail out */
 377                         break;
 378                 }
 379                 snprintf(res20, 20, "<%d>", pri);
 380         }
 381 }
 382
 383 /* len parameter is used only for "is there a timestamp?" check.
 384  * NB: some callers cheat and supply 0 when they know
 385  * that there is no timestamp, short-cutting the test. */
 386 static void timestamp_and_log(int pri, char *msg, int len)
 387 {
 388         char *timestamp;
 389
 390         if (len < 16 || msg[3] != ' ' || msg[6] != ' '
 391          || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
 392         ) {
 393                 time_t now;
 394                 time(&now);
 395                 timestamp = ctime(&now) + 4;
 396         } else {
 397                 timestamp = msg;
 398                 msg += 16;
 399         }
 400         timestamp[15] = '\0';
 401
 402         /* Log message locally (to file or shared mem) */
 403         if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
 404                 if (LOG_PRI(pri) < G.logLevel) {
 405                         if (option_mask32 & OPT_small)
 406                                 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
 407                         else {
 408                                 char res[20];
 409                                 parse_fac_prio_20(pri, res);
 410                                 sprintf(G.printbuf, "%s %s %s %s\n", timestamp, G.localHostName, res, msg);
 411                         }
 412                         log_locally(G.printbuf);
 413                 }
 414         }
 415 }
 416
 417 static void split_escape_and_log(char *tmpbuf, int len)
 418 {
 419         char *p = tmpbuf;
 420
 421         tmpbuf += len;
 422         while (p < tmpbuf) {
 423                 char c;
 424                 char *q = G.parsebuf;
 425                 int pri = (LOG_USER | LOG_NOTICE);
 426
 427                 if (*p == '<') {
 428                         /* Parse the magic priority number */
 429                         pri = bb_strtou(p + 1, &p, 10);
 430                         if (*p == '>') p++;
 431                         if (pri & ~(LOG_FACMASK | LOG_PRIMASK)) {
 432                                 pri = (LOG_USER | LOG_NOTICE);
 433                         }
 434                 }
 435
 436                 while ((c = *p++)) {
 437                         if (c == '\n')
 438                                 c = ' ';
 439                         if (!(c & ~0x1f) && c != '\t') {
 440                                 *q++ = '^';
 441                                 c += '@'; /* ^@, ^A, ^B... */
 442                         }
 443                         *q++ = c;
 444                 }
 445                 *q = '\0';
 446                 /* Now log it */
 447                 timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
 448         }
 449 }
 450
 451 static void quit_signal(int sig)
 452 {
 453         timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)"syslogd exiting", 0);
 454         puts("syslogd exiting");
 455         if (ENABLE_FEATURE_IPC_SYSLOG)
 456                 ipcsyslog_cleanup();
 457         exit(1);
 458 }
 459
 460 #ifdef SYSLOGD_MARK
 461 static void do_mark(int sig)
 462 {
 463         if (G.markInterval) {
 464                 timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)"-- MARK --", 0);
 465                 alarm(G.markInterval);
 466         }
 467 }
 468 #endif
 469
 470 static void do_syslogd(void) ATTRIBUTE_NORETURN;
 471 static void do_syslogd(void)
 472 {
 473         struct sockaddr_un sunx;
 474         int sock_fd;
 475         fd_set fds;
 476         char *dev_log_name;
 477
 478         /* Set up signal handlers */
 479         signal(SIGINT, quit_signal);
 480         signal(SIGTERM, quit_signal);
 481         signal(SIGQUIT, quit_signal);
 482         signal(SIGHUP, SIG_IGN);
 483         signal(SIGCHLD, SIG_IGN);
 484 #ifdef SIGCLD
 485         signal(SIGCLD, SIG_IGN);
 486 #endif
 487 #ifdef SYSLOGD_MARK
 488         signal(SIGALRM, do_mark);
 489         alarm(G.markInterval);
 490 #endif
 491         remove_pidfile("/var/run/syslogd.pid");
 492
 493         memset(&sunx, 0, sizeof(sunx));
 494         sunx.sun_family = AF_UNIX;
 495         strcpy(sunx.sun_path, "/dev/log");
 496
 497         /* Unlink old /dev/log or object it points to. */
 498         /* (if it exists, bind will fail) */
 499         logmode = LOGMODE_NONE;
 500         dev_log_name = xmalloc_readlink_or_warn("/dev/log");
 501         logmode = LOGMODE_STDIO;
 502         if (dev_log_name) {
 503                 int fd = xopen(".", O_NONBLOCK);
 504                 xchdir("/dev");
 505                 /* we do not check whether this is a link also */
 506                 unlink(dev_log_name);
 507                 fchdir(fd);
 508                 close(fd);
 509                 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
 510                 free(dev_log_name);
 511         } else {
 512                 unlink("/dev/log");
 513         }
 514
 515         sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
 516         xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
 517
 518         if (chmod("/dev/log", 0666) < 0) {
 519                 bb_perror_msg_and_die("cannot set permission on /dev/log");
 520         }
 521         if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
 522                 ipcsyslog_init();
 523         }
 524
 525         timestamp_and_log(LOG_SYSLOG | LOG_INFO,
 526                         (char*)"syslogd started: BusyBox v" BB_VER, 0);
 527
 528         for (;;) {
 529                 FD_ZERO(&fds);
 530                 FD_SET(sock_fd, &fds);
 531
 532                 if (select(sock_fd + 1, &fds, NULL, NULL, NULL) < 0) {
 533                         if (errno == EINTR) {
 534                                 /* alarm may have happened */
 535                                 continue;
 536                         }
 537                         bb_perror_msg_and_die("select");
 538                 }
 539
 540                 if (FD_ISSET(sock_fd, &fds)) {
 541                         int i;
 542                         i = recv(sock_fd, G.recvbuf, MAX_READ - 1, 0);
 543                         if (i <= 0)
 544                                 bb_perror_msg_and_die("UNIX socket error");
 545                         /* TODO: maybe suppress duplicates? */
 546 #if ENABLE_FEATURE_REMOTE_LOG
 547                         /* We are not modifying log messages in any way before send */
 548                         /* Remote site cannot trust _us_ anyway and need to do validation again */
 549                         if (G.remoteAddr) {
 550                                 if (-1 == G.remoteFD) {
 551                                         G.remoteFD = socket(G.remoteAddr->sa.sa_family, SOCK_DGRAM, 0);
 552                                 }
 553                                 if (-1 != G.remoteFD) {
 554                                         /* send message to remote logger, ignore possible error */
 555                                         sendto(G.remoteFD, G.recvbuf, i, MSG_DONTWAIT,
 556                                                 &G.remoteAddr->sa, G.remoteAddr->len);
 557                                 }
 558                         }
 559 #endif
 560                         G.recvbuf[i] = '\0';
 561                         split_escape_and_log(G.recvbuf, i);
 562                 } /* FD_ISSET() */
 563         } /* for */
 564 }
 565
 566 int syslogd_main(int argc, char **argv);
 567 int syslogd_main(int argc, char **argv)
 568 {
 569         char OPTION_DECL;
 570         char *p;
 571
 572         PTR_TO_GLOBALS = memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data));
 573
 574         /* do normal option parsing */
 575         opt_complementary = "=0"; /* no non-option params */
 576         getopt32(argc, argv, OPTION_STR, OPTION_PARAM);
 577 #ifdef SYSLOGD_MARK
 578         if (option_mask32 & OPT_mark) // -m
 579                 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
 580 #endif
 581         //if (option_mask32 & OPT_nofork) // -n
 582         //if (option_mask32 & OPT_outfile) // -O
 583         if (option_mask32 & OPT_loglevel) // -l
 584                 G.logLevel = xatou_range(opt_l, 1, 8);
 585         //if (option_mask32 & OPT_small) // -S
 586 #if ENABLE_FEATURE_ROTATE_LOGFILE
 587         if (option_mask32 & OPT_filesize) // -s
 588                 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
 589         if (option_mask32 & OPT_rotatecnt) // -b
 590                 G.logFileRotate = xatou_range(opt_b, 0, 99);
 591 #endif
 592 #if ENABLE_FEATURE_REMOTE_LOG
 593         if (option_mask32 & OPT_remotelog) { // -R
 594                 G.remoteAddr = xhost2sockaddr(opt_R, 514);
 595         }
 596         //if (option_mask32 & OPT_locallog) // -L
 597 #endif
 598 #if ENABLE_FEATURE_IPC_SYSLOG
 599         if (opt_C) // -Cn
 600                 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
 601 #endif
 602
 603         /* If they have not specified remote logging, then log locally */
 604         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_remotelog))
 605                 option_mask32 |= OPT_locallog;
 606
 607         /* Store away localhost's name before the fork */
 608         gethostname(G.localHostName, sizeof(G.localHostName));
 609         p = strchr(G.localHostName, '.');
 610         if (p) {
 611                 *p = '\0';
 612         }
 613
 614         if (!(option_mask32 & OPT_nofork)) {
 615                 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
 616         }
 617         umask(0);
 618         write_pidfile("/var/run/syslogd.pid");
 619         do_syslogd();
 620         /* return EXIT_SUCCESS; */
 621 }