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 #define SYSLOG_NAMES
  18 #define SYSLOG_NAMES_CONST
  19 #include <syslog.h>
  20
  21 #include <paths.h>
  22 #include <sys/un.h>
  23 #include <sys/uio.h>
  24
  25 #if ENABLE_FEATURE_REMOTE_LOG
  26 #include <netinet/in.h>
  27 #endif
  28
  29 #if ENABLE_FEATURE_IPC_SYSLOG
  30 #include <sys/ipc.h>
  31 #include <sys/sem.h>
  32 #include <sys/shm.h>
  33 #endif
  34
  35
  36 #define DEBUG 0
  37
  38 /* MARK code is not very useful, is bloat, and broken:
  39  * can deadlock if alarmed to make MARK while writing to IPC buffer
  40  * (semaphores are down but do_mark routine tries to down them again) */
  41 #undef SYSLOGD_MARK
  42
  43 enum {
  44         MAX_READ = 256,
  45         DNS_WAIT_SEC = 2 * 60,
  46 };
  47
  48 /* Semaphore operation structures */
  49 struct shbuf_ds {
  50         int32_t size;   /* size of data - 1 */
  51         int32_t tail;   /* end of message list */
  52         char data[1];   /* data/messages */
  53 };
  54
  55 /* Allows us to have smaller initializer. Ugly. */
  56 #define GLOBALS \
  57         const char *logFilePath;                \
  58         int logFD;                              \
  59         /* interval between marks in seconds */ \
  60         /*int markInterval;*/                   \
  61         /* level of messages to be logged */    \
  62         int logLevel;                           \
  63 USE_FEATURE_ROTATE_LOGFILE( \
  64         /* max size of file before rotation */  \
  65         unsigned logFileSize;                   \
  66         /* number of rotated message files */   \
  67         unsigned logFileRotate;                 \
  68         unsigned curFileSize;                   \
  69         smallint isRegular;                     \
  70 ) \
  71 USE_FEATURE_REMOTE_LOG( \
  72         /* udp socket for remote logging */     \
  73         int remoteFD;                           \
  74         len_and_sockaddr* remoteAddr;           \
  75 ) \
  76 USE_FEATURE_IPC_SYSLOG( \
  77         int shmid; /* ipc shared memory id */   \
  78         int s_semid; /* ipc semaphore id */     \
  79         int shm_size;                           \
  80         struct sembuf SMwup[1];                 \
  81         struct sembuf SMwdn[3];                 \
  82 )
  83
  84 struct init_globals {
  85         GLOBALS
  86 };
  87
  88 struct globals {
  89         GLOBALS
  90
  91 #if ENABLE_FEATURE_REMOTE_LOG
  92         unsigned last_dns_resolve;
  93         char *remoteAddrStr;
  94 #endif
  95
  96 #if ENABLE_FEATURE_IPC_SYSLOG
  97         struct shbuf_ds *shbuf;
  98 #endif
  99         time_t last_log_time;
 100         /* localhost's name. We print only first 64 chars */
 101         char *hostname;
 102
 103         /* We recv into recvbuf... */
 104         char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
 105         /* ...then copy to parsebuf, escaping control chars */
 106         /* (can grow x2 max) */
 107         char parsebuf[MAX_READ*2];
 108         /* ...then sprintf into printbuf, adding timestamp (15 chars),
 109          * host (64), fac.prio (20) to the message */
 110         /* (growth by: 15 + 64 + 20 + delims = ~110) */
 111         char printbuf[MAX_READ*2 + 128];
 112 };
 113
 114 static const struct init_globals init_data = {
 115         .logFilePath = "/var/log/messages",
 116         .logFD = -1,
 117 #ifdef SYSLOGD_MARK
 118         .markInterval = 20 * 60,
 119 #endif
 120         .logLevel = 8,
 121 #if ENABLE_FEATURE_ROTATE_LOGFILE
 122         .logFileSize = 200 * 1024,
 123         .logFileRotate = 1,
 124 #endif
 125 #if ENABLE_FEATURE_REMOTE_LOG
 126         .remoteFD = -1,
 127 #endif
 128 #if ENABLE_FEATURE_IPC_SYSLOG
 129         .shmid = -1,
 130         .s_semid = -1,
 131         .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), // default shm size
 132         .SMwup = { {1, -1, IPC_NOWAIT} },
 133         .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
 134 #endif
 135 };
 136
 137 #define G (*ptr_to_globals)
 138 #define INIT_G() do { \
 139         SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
 140 } while (0)
 141
 142
 143 /* Options */
 144 enum {
 145         OPTBIT_mark = 0, // -m
 146         OPTBIT_nofork, // -n
 147         OPTBIT_outfile, // -O
 148         OPTBIT_loglevel, // -l
 149         OPTBIT_small, // -S
 150         USE_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,) // -s
 151         USE_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,) // -b
 152         USE_FEATURE_REMOTE_LOG(    OPTBIT_remote     ,) // -R
 153         USE_FEATURE_REMOTE_LOG(    OPTBIT_locallog   ,) // -L
 154         USE_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,) // -C
 155         USE_FEATURE_SYSLOGD_DUP(   OPTBIT_dup        ,) // -D
 156
 157         OPT_mark        = 1 << OPTBIT_mark    ,
 158         OPT_nofork      = 1 << OPTBIT_nofork  ,
 159         OPT_outfile     = 1 << OPTBIT_outfile ,
 160         OPT_loglevel    = 1 << OPTBIT_loglevel,
 161         OPT_small       = 1 << OPTBIT_small   ,
 162         OPT_filesize    = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
 163         OPT_rotatecnt   = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
 164         OPT_remotelog   = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remote     )) + 0,
 165         OPT_locallog    = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_locallog   )) + 0,
 166         OPT_circularlog = USE_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
 167         OPT_dup         = USE_FEATURE_SYSLOGD_DUP(   (1 << OPTBIT_dup        )) + 0,
 168 };
 169 #define OPTION_STR "m:nO:l:S" \
 170         USE_FEATURE_ROTATE_LOGFILE("s:" ) \
 171         USE_FEATURE_ROTATE_LOGFILE("b:" ) \
 172         USE_FEATURE_REMOTE_LOG(    "R:" ) \
 173         USE_FEATURE_REMOTE_LOG(    "L"  ) \
 174         USE_FEATURE_IPC_SYSLOG(    "C::") \
 175         USE_FEATURE_SYSLOGD_DUP(   "D"  )
 176 #define OPTION_DECL *opt_m, *opt_l \
 177         USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
 178         USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
 179         USE_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL)
 180 #define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \
 181         USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
 182         USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
 183         USE_FEATURE_REMOTE_LOG(    ,&G.remoteAddrStr) \
 184         USE_FEATURE_IPC_SYSLOG(    ,&opt_C)
 185
 186
 187 /* circular buffer variables/structures */
 188 #if ENABLE_FEATURE_IPC_SYSLOG
 189
 190 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
 191 #error Sorry, you must set the syslogd buffer size to at least 4KB.
 192 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 193 #endif
 194
 195 /* our shared key */
 196 #define KEY_ID ((long)0x414e4547) /* "GENA" */
 197
 198 static void ipcsyslog_cleanup(void)
 199 {
 200         if (G.shmid != -1) {
 201                 shmdt(G.shbuf);
 202         }
 203         if (G.shmid != -1) {
 204                 shmctl(G.shmid, IPC_RMID, NULL);
 205         }
 206         if (G.s_semid != -1) {
 207                 semctl(G.s_semid, 0, IPC_RMID, 0);
 208         }
 209 }
 210
 211 static void ipcsyslog_init(void)
 212 {
 213         if (DEBUG)
 214                 printf("shmget(%lx, %d,...)\n", KEY_ID, G.shm_size);
 215
 216         G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
 217         if (G.shmid == -1) {
 218                 bb_perror_msg_and_die("shmget");
 219         }
 220
 221         G.shbuf = shmat(G.shmid, NULL, 0);
 222         if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
 223                 bb_perror_msg_and_die("shmat");
 224         }
 225
 226         memset(G.shbuf, 0, G.shm_size);
 227         G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
 228         /*G.shbuf->tail = 0;*/
 229
 230         // we'll trust the OS to set initial semval to 0 (let's hope)
 231         G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
 232         if (G.s_semid == -1) {
 233                 if (errno == EEXIST) {
 234                         G.s_semid = semget(KEY_ID, 2, 0);
 235                         if (G.s_semid != -1)
 236                                 return;
 237                 }
 238                 bb_perror_msg_and_die("semget");
 239         }
 240 }
 241
 242 /* Write message to shared mem buffer */
 243 static void log_to_shmem(const char *msg, int len)
 244 {
 245         int old_tail, new_tail;
 246
 247         if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 248                 bb_perror_msg_and_die("SMwdn");
 249         }
 250
 251         /* Circular Buffer Algorithm:
 252          * --------------------------
 253          * tail == position where to store next syslog message.
 254          * tail's max value is (shbuf->size - 1)
 255          * Last byte of buffer is never used and remains NUL.
 256          */
 257         len++; /* length with NUL included */
 258  again:
 259         old_tail = G.shbuf->tail;
 260         new_tail = old_tail + len;
 261         if (new_tail < G.shbuf->size) {
 262                 /* store message, set new tail */
 263                 memcpy(G.shbuf->data + old_tail, msg, len);
 264                 G.shbuf->tail = new_tail;
 265         } else {
 266                 /* k == available buffer space ahead of old tail */
 267                 int k = G.shbuf->size - old_tail;
 268                 /* copy what fits to the end of buffer, and repeat */
 269                 memcpy(G.shbuf->data + old_tail, msg, k);
 270                 msg += k;
 271                 len -= k;
 272                 G.shbuf->tail = 0;
 273                 goto again;
 274         }
 275         if (semop(G.s_semid, G.SMwup, 1) == -1) {
 276                 bb_perror_msg_and_die("SMwup");
 277         }
 278         if (DEBUG)
 279                 printf("tail:%d\n", G.shbuf->tail);
 280 }
 281 #else
 282 void ipcsyslog_cleanup(void);
 283 void ipcsyslog_init(void);
 284 void log_to_shmem(const char *msg);
 285 #endif /* FEATURE_IPC_SYSLOG */
 286
 287
 288 /* Print a message to the log file. */
 289 static void log_locally(time_t now, char *msg)
 290 {
 291         struct flock fl;
 292         int len = strlen(msg);
 293
 294 #if ENABLE_FEATURE_IPC_SYSLOG
 295         if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 296                 log_to_shmem(msg, len);
 297                 return;
 298         }
 299 #endif
 300         if (G.logFD >= 0) {
 301                 if (!now)
 302                         now = time(NULL);
 303                 if (G.last_log_time != now) {
 304                         G.last_log_time = now; /* reopen log file every second */
 305                         close(G.logFD);
 306                         goto reopen;
 307                 }
 308         } else {
 309  reopen:
 310                 G.logFD = device_open(G.logFilePath, O_WRONLY | O_CREAT
 311                                         | O_NOCTTY | O_APPEND | O_NONBLOCK);
 312                 if (G.logFD < 0) {
 313                         /* cannot open logfile? - print to /dev/console then */
 314                         int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
 315                         if (fd < 0)
 316                                 fd = 2; /* then stderr, dammit */
 317                         full_write(fd, msg, len);
 318                         if (fd != 2)
 319                                 close(fd);
 320                         return;
 321                 }
 322 #if ENABLE_FEATURE_ROTATE_LOGFILE
 323                 {
 324                         struct stat statf;
 325                         G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode));
 326                         /* bug (mostly harmless): can wrap around if file > 4gb */
 327                         G.curFileSize = statf.st_size;
 328                 }
 329 #endif
 330         }
 331
 332         fl.l_whence = SEEK_SET;
 333         fl.l_start = 0;
 334         fl.l_len = 1;
 335         fl.l_type = F_WRLCK;
 336         fcntl(G.logFD, F_SETLKW, &fl);
 337
 338 #if ENABLE_FEATURE_ROTATE_LOGFILE
 339         if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) {
 340                 if (G.logFileRotate) { /* always 0..99 */
 341                         int i = strlen(G.logFilePath) + 3 + 1;
 342                         char oldFile[i];
 343                         char newFile[i];
 344                         i = G.logFileRotate - 1;
 345                         /* rename: f.8 -> f.9; f.7 -> f.8; ... */
 346                         while (1) {
 347                                 sprintf(newFile, "%s.%d", G.logFilePath, i);
 348                                 if (i == 0) break;
 349                                 sprintf(oldFile, "%s.%d", G.logFilePath, --i);
 350                                 /* ignore errors - file might be missing */
 351                                 rename(oldFile, newFile);
 352                         }
 353                         /* newFile == "f.0" now */
 354                         rename(G.logFilePath, newFile);
 355                         fl.l_type = F_UNLCK;
 356                         fcntl(G.logFD, F_SETLKW, &fl);
 357                         close(G.logFD);
 358                         goto reopen;
 359                 }
 360                 ftruncate(G.logFD, 0);
 361         }
 362         G.curFileSize +=
 363 #endif
 364                         full_write(G.logFD, msg, len);
 365         fl.l_type = F_UNLCK;
 366         fcntl(G.logFD, F_SETLKW, &fl);
 367 }
 368
 369 static void parse_fac_prio_20(int pri, char *res20)
 370 {
 371         const CODE *c_pri, *c_fac;
 372
 373         if (pri != 0) {
 374                 c_fac = facilitynames;
 375                 while (c_fac->c_name) {
 376                         if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
 377                                 c_fac++;
 378                                 continue;
 379                         }
 380                         /* facility is found, look for prio */
 381                         c_pri = prioritynames;
 382                         while (c_pri->c_name) {
 383                                 if (c_pri->c_val != LOG_PRI(pri)) {
 384                                         c_pri++;
 385                                         continue;
 386                                 }
 387                                 snprintf(res20, 20, "%s.%s",
 388                                                 c_fac->c_name, c_pri->c_name);
 389                                 return;
 390                         }
 391                         /* prio not found, bail out */
 392                         break;
 393                 }
 394                 snprintf(res20, 20, "<%d>", pri);
 395         }
 396 }
 397
 398 /* len parameter is used only for "is there a timestamp?" check.
 399  * NB: some callers cheat and supply len==0 when they know
 400  * that there is no timestamp, short-circuiting the test. */
 401 static void timestamp_and_log(int pri, char *msg, int len)
 402 {
 403         char *timestamp;
 404         time_t now;
 405
 406         if (len < 16 || msg[3] != ' ' || msg[6] != ' '
 407          || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
 408         ) {
 409                 time(&now);
 410                 timestamp = ctime(&now) + 4; /* skip day of week */
 411         } else {
 412                 now = 0;
 413                 timestamp = msg;
 414                 msg += 16;
 415         }
 416         timestamp[15] = '\0';
 417
 418         if (option_mask32 & OPT_small)
 419                 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
 420         else {
 421                 char res[20];
 422                 parse_fac_prio_20(pri, res);
 423                 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
 424         }
 425
 426         /* Log message locally (to file or shared mem) */
 427         log_locally(now, G.printbuf);
 428 }
 429
 430 static void timestamp_and_log_internal(const char *msg)
 431 {
 432         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
 433                 return;
 434         timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
 435 }
 436
 437 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
 438  * embedded NULs. Split messages on each of these NULs, parse prio,
 439  * escape control chars and log each locally. */
 440 static void split_escape_and_log(char *tmpbuf, int len)
 441 {
 442         char *p = tmpbuf;
 443
 444         tmpbuf += len;
 445         while (p < tmpbuf) {
 446                 char c;
 447                 char *q = G.parsebuf;
 448                 int pri = (LOG_USER | LOG_NOTICE);
 449
 450                 if (*p == '<') {
 451                         /* Parse the magic priority number */
 452                         pri = bb_strtou(p + 1, &p, 10);
 453                         if (*p == '>')
 454                                 p++;
 455                         if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 456                                 pri = (LOG_USER | LOG_NOTICE);
 457                 }
 458
 459                 while ((c = *p++)) {
 460                         if (c == '\n')
 461                                 c = ' ';
 462                         if (!(c & ~0x1f) && c != '\t') {
 463                                 *q++ = '^';
 464                                 c += '@'; /* ^@, ^A, ^B... */
 465                         }
 466                         *q++ = c;
 467                 }
 468                 *q = '\0';
 469
 470                 /* Now log it */
 471                 if (LOG_PRI(pri) < G.logLevel)
 472                         timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
 473         }
 474 }
 475
 476 static void quit_signal(int sig)
 477 {
 478         timestamp_and_log_internal("syslogd exiting");
 479         puts("syslogd exiting");
 480         if (ENABLE_FEATURE_IPC_SYSLOG)
 481                 ipcsyslog_cleanup();
 482         kill_myself_with_sig(sig);
 483 }
 484
 485 #ifdef SYSLOGD_MARK
 486 static void do_mark(int sig)
 487 {
 488         if (G.markInterval) {
 489                 timestamp_and_log_internal("-- MARK --");
 490                 alarm(G.markInterval);
 491         }
 492 }
 493 #endif
 494
 495 /* Don't inline: prevent struct sockaddr_un to take up space on stack
 496  * permanently */
 497 static NOINLINE int create_socket(void)
 498 {
 499         struct sockaddr_un sunx;
 500         int sock_fd;
 501         char *dev_log_name;
 502
 503         memset(&sunx, 0, sizeof(sunx));
 504         sunx.sun_family = AF_UNIX;
 505
 506         /* Unlink old /dev/log or object it points to. */
 507         /* (if it exists, bind will fail) */
 508         strcpy(sunx.sun_path, "/dev/log");
 509         dev_log_name = xmalloc_follow_symlinks("/dev/log");
 510         if (dev_log_name) {
 511                 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
 512                 free(dev_log_name);
 513         }
 514         unlink(sunx.sun_path);
 515
 516         sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
 517         xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
 518         chmod("/dev/log", 0666);
 519
 520         return sock_fd;
 521 }
 522
 523 #if ENABLE_FEATURE_REMOTE_LOG
 524 static int try_to_resolve_remote(void)
 525 {
 526         if (!G.remoteAddr) {
 527                 unsigned now = monotonic_sec();
 528
 529                 /* Don't resolve name too often - DNS timeouts can be big */
 530                 if ((now - G.last_dns_resolve) < DNS_WAIT_SEC)
 531                         return -1;
 532                 G.last_dns_resolve = now;
 533                 G.remoteAddr = host2sockaddr(G.remoteAddrStr, 514);
 534                 if (!G.remoteAddr)
 535                         return -1;
 536         }
 537         return socket(G.remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
 538 }
 539 #endif
 540
 541 static void do_syslogd(void) ATTRIBUTE_NORETURN;
 542 static void do_syslogd(void)
 543 {
 544         int sock_fd;
 545 #if ENABLE_FEATURE_SYSLOGD_DUP
 546         int last_sz = -1;
 547         char *last_buf;
 548         char *recvbuf = G.recvbuf;
 549 #else
 550 #define recvbuf (G.recvbuf)
 551 #endif
 552
 553         /* Set up signal handlers */
 554         bb_signals(0
 555                 + (1 << SIGINT)
 556                 + (1 << SIGTERM)
 557                 + (1 << SIGQUIT)
 558                 , quit_signal);
 559         signal(SIGHUP, SIG_IGN);
 560         /* signal(SIGCHLD, SIG_IGN); - why? */
 561 #ifdef SYSLOGD_MARK
 562         signal(SIGALRM, do_mark);
 563         alarm(G.markInterval);
 564 #endif
 565         sock_fd = create_socket();
 566
 567         if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
 568                 ipcsyslog_init();
 569         }
 570
 571         timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
 572
 573         for (;;) {
 574                 ssize_t sz;
 575
 576 #if ENABLE_FEATURE_SYSLOGD_DUP
 577                 last_buf = recvbuf;
 578                 if (recvbuf == G.recvbuf)
 579                         recvbuf = G.recvbuf + MAX_READ;
 580                 else
 581                         recvbuf = G.recvbuf;
 582 #endif
 583  read_again:
 584                 sz = safe_read(sock_fd, recvbuf, MAX_READ - 1);
 585                 if (sz < 0)
 586                         bb_perror_msg_and_die("read from /dev/log");
 587
 588                 /* Drop trailing '\n' and NULs (typically there is one NUL) */
 589                 while (1) {
 590                         if (sz == 0)
 591                                 goto read_again;
 592                         /* man 3 syslog says: "A trailing newline is added when needed".
 593                          * However, neither glibc nor uclibc do this:
 594                          * syslog(prio, "test")   sends "test\0" to /dev/log,
 595                          * syslog(prio, "test\n") sends "test\n\0".
 596                          * IOW: newline is passed verbatim!
 597                          * I take it to mean that it's syslogd's job
 598                          * to make those look identical in the log files. */
 599                         if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
 600                                 break;
 601                         sz--;
 602                 }
 603 #if ENABLE_FEATURE_SYSLOGD_DUP
 604                 if ((option_mask32 & OPT_dup) && (sz == last_sz))
 605                         if (memcmp(last_buf, recvbuf, sz) == 0)
 606                                 continue;
 607                 last_sz = sz;
 608 #endif
 609 #if ENABLE_FEATURE_REMOTE_LOG
 610                 /* We are not modifying log messages in any way before send */
 611                 /* Remote site cannot trust _us_ anyway and need to do validation again */
 612                 if (G.remoteAddrStr) {
 613                         if (-1 == G.remoteFD) {
 614                                 G.remoteFD = try_to_resolve_remote();
 615                                 if (-1 == G.remoteFD)
 616                                         goto no_luck;
 617                         }
 618                         /* Stock syslogd sends it '\n'-terminated
 619                          * over network, mimic that */
 620                         recvbuf[sz] = '\n';
 621                         /* send message to remote logger, ignore possible error */
 622                         /* TODO: on some errors, close and set G.remoteFD to -1
 623                          * so that DNS resolution and connect is retried? */
 624                         sendto(G.remoteFD, recvbuf, sz+1, MSG_DONTWAIT,
 625                                     &G.remoteAddr->u.sa, G.remoteAddr->len);
 626  no_luck: ;
 627                 }
 628 #endif
 629                 if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
 630                         recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
 631                         split_escape_and_log(recvbuf, sz);
 632                 }
 633         } /* for (;;) */
 634 }
 635
 636 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 637 int syslogd_main(int argc ATTRIBUTE_UNUSED, char **argv)
 638 {
 639         char OPTION_DECL;
 640
 641         INIT_G();
 642 #if ENABLE_FEATURE_REMOTE_LOG
 643         G.last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
 644 #endif
 645
 646         /* do normal option parsing */
 647         opt_complementary = "=0"; /* no non-option params */
 648         getopt32(argv, OPTION_STR, OPTION_PARAM);
 649 #ifdef SYSLOGD_MARK
 650         if (option_mask32 & OPT_mark) // -m
 651                 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
 652 #endif
 653         //if (option_mask32 & OPT_nofork) // -n
 654         //if (option_mask32 & OPT_outfile) // -O
 655         if (option_mask32 & OPT_loglevel) // -l
 656                 G.logLevel = xatou_range(opt_l, 1, 8);
 657         //if (option_mask32 & OPT_small) // -S
 658 #if ENABLE_FEATURE_ROTATE_LOGFILE
 659         if (option_mask32 & OPT_filesize) // -s
 660                 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
 661         if (option_mask32 & OPT_rotatecnt) // -b
 662                 G.logFileRotate = xatou_range(opt_b, 0, 99);
 663 #endif
 664 #if ENABLE_FEATURE_IPC_SYSLOG
 665         if (opt_C) // -Cn
 666                 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
 667 #endif
 668
 669         /* If they have not specified remote logging, then log locally */
 670         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_remotelog))
 671                 option_mask32 |= OPT_locallog;
 672
 673         /* Store away localhost's name before the fork */
 674         G.hostname = safe_gethostname();
 675         *strchrnul(G.hostname, '.') = '\0';
 676
 677         if (!(option_mask32 & OPT_nofork)) {
 678                 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
 679         }
 680         umask(0);
 681         write_pidfile("/var/run/syslogd.pid");
 682         do_syslogd();
 683         /* return EXIT_SUCCESS; */
 684 }