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 enum {
  47         MAX_READ = 256,
  48         DNS_WAIT_SEC = 2 * 60,
  49 };
  50
  51 /* Semaphore operation structures */
  52 struct shbuf_ds {
  53         int32_t size;   /* size of data - 1 */
  54         int32_t tail;   /* end of message list */
  55         char data[1];   /* data/messages */
  56 };
  57
  58 /* Allows us to have smaller initializer. Ugly. */
  59 #define GLOBALS \
  60         const char *logFilePath;                \
  61         int logFD;                              \
  62         /* interval between marks in seconds */ \
  63         /*int markInterval;*/                   \
  64         /* level of messages to be logged */    \
  65         int logLevel;                           \
  66 USE_FEATURE_ROTATE_LOGFILE( \
  67         /* max size of file before rotation */  \
  68         unsigned logFileSize;                   \
  69         /* number of rotated message files */   \
  70         unsigned logFileRotate;                 \
  71         unsigned curFileSize;                   \
  72         smallint isRegular;                     \
  73 ) \
  74 USE_FEATURE_REMOTE_LOG( \
  75         /* udp socket for remote logging */     \
  76         int remoteFD;                           \
  77         len_and_sockaddr* remoteAddr;           \
  78 ) \
  79 USE_FEATURE_IPC_SYSLOG( \
  80         int shmid; /* ipc shared memory id */   \
  81         int s_semid; /* ipc semaphore id */     \
  82         int shm_size;                           \
  83         struct sembuf SMwup[1];                 \
  84         struct sembuf SMwdn[3];                 \
  85 )
  86
  87 struct init_globals {
  88         GLOBALS
  89 };
  90
  91 struct globals {
  92         GLOBALS
  93
  94 #if ENABLE_FEATURE_REMOTE_LOG
  95         unsigned last_dns_resolve;
  96         char *remoteAddrStr;
  97 #endif
  98
  99 #if ENABLE_FEATURE_IPC_SYSLOG
 100         struct shbuf_ds *shbuf;
 101 #endif
 102         time_t last_log_time;
 103         /* localhost's name. We print only first 64 chars */
 104         char *hostname;
 105
 106         /* We recv into recvbuf... */
 107         char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
 108         /* ...then copy to parsebuf, escaping control chars */
 109         /* (can grow x2 max) */
 110         char parsebuf[MAX_READ*2];
 111         /* ...then sprintf into printbuf, adding timestamp (15 chars),
 112          * host (64), fac.prio (20) to the message */
 113         /* (growth by: 15 + 64 + 20 + delims = ~110) */
 114         char printbuf[MAX_READ*2 + 128];
 115 };
 116
 117 static const struct init_globals init_data = {
 118         .logFilePath = "/var/log/messages",
 119         .logFD = -1,
 120 #ifdef SYSLOGD_MARK
 121         .markInterval = 20 * 60,
 122 #endif
 123         .logLevel = 8,
 124 #if ENABLE_FEATURE_ROTATE_LOGFILE
 125         .logFileSize = 200 * 1024,
 126         .logFileRotate = 1,
 127 #endif
 128 #if ENABLE_FEATURE_REMOTE_LOG
 129         .remoteFD = -1,
 130 #endif
 131 #if ENABLE_FEATURE_IPC_SYSLOG
 132         .shmid = -1,
 133         .s_semid = -1,
 134         .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), // default shm size
 135         .SMwup = { {1, -1, IPC_NOWAIT} },
 136         .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
 137 #endif
 138 };
 139
 140 #define G (*ptr_to_globals)
 141 #define INIT_G() do { \
 142         SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
 143 } while (0)
 144
 145
 146 /* Options */
 147 enum {
 148         OPTBIT_mark = 0, // -m
 149         OPTBIT_nofork, // -n
 150         OPTBIT_outfile, // -O
 151         OPTBIT_loglevel, // -l
 152         OPTBIT_small, // -S
 153         USE_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,) // -s
 154         USE_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,) // -b
 155         USE_FEATURE_REMOTE_LOG(    OPTBIT_remote     ,) // -R
 156         USE_FEATURE_REMOTE_LOG(    OPTBIT_locallog   ,) // -L
 157         USE_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,) // -C
 158         USE_FEATURE_SYSLOGD_DUP(   OPTBIT_dup        ,) // -D
 159
 160         OPT_mark        = 1 << OPTBIT_mark    ,
 161         OPT_nofork      = 1 << OPTBIT_nofork  ,
 162         OPT_outfile     = 1 << OPTBIT_outfile ,
 163         OPT_loglevel    = 1 << OPTBIT_loglevel,
 164         OPT_small       = 1 << OPTBIT_small   ,
 165         OPT_filesize    = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
 166         OPT_rotatecnt   = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
 167         OPT_remotelog   = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remote     )) + 0,
 168         OPT_locallog    = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_locallog   )) + 0,
 169         OPT_circularlog = USE_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
 170         OPT_dup         = USE_FEATURE_SYSLOGD_DUP(   (1 << OPTBIT_dup        )) + 0,
 171 };
 172 #define OPTION_STR "m:nO:l:S" \
 173         USE_FEATURE_ROTATE_LOGFILE("s:" ) \
 174         USE_FEATURE_ROTATE_LOGFILE("b:" ) \
 175         USE_FEATURE_REMOTE_LOG(    "R:" ) \
 176         USE_FEATURE_REMOTE_LOG(    "L"  ) \
 177         USE_FEATURE_IPC_SYSLOG(    "C::") \
 178         USE_FEATURE_SYSLOGD_DUP(   "D"  )
 179 #define OPTION_DECL *opt_m, *opt_l \
 180         USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
 181         USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
 182         USE_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL)
 183 #define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \
 184         USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
 185         USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
 186         USE_FEATURE_REMOTE_LOG(    ,&G.remoteAddrStr) \
 187         USE_FEATURE_IPC_SYSLOG(    ,&opt_C)
 188
 189
 190 /* circular buffer variables/structures */
 191 #if ENABLE_FEATURE_IPC_SYSLOG
 192
 193 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
 194 #error Sorry, you must set the syslogd buffer size to at least 4KB.
 195 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 196 #endif
 197
 198 /* our shared key (syslogd.c and logread.c must be in sync) */
 199 enum { KEY_ID = 0x414e4547 }; /* "GENA" */
 200
 201 static void ipcsyslog_cleanup(void)
 202 {
 203         if (G.shmid != -1) {
 204                 shmdt(G.shbuf);
 205         }
 206         if (G.shmid != -1) {
 207                 shmctl(G.shmid, IPC_RMID, NULL);
 208         }
 209         if (G.s_semid != -1) {
 210                 semctl(G.s_semid, 0, IPC_RMID, 0);
 211         }
 212 }
 213
 214 static void ipcsyslog_init(void)
 215 {
 216         if (DEBUG)
 217                 printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
 218
 219         G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
 220         if (G.shmid == -1) {
 221                 bb_perror_msg_and_die("shmget");
 222         }
 223
 224         G.shbuf = shmat(G.shmid, NULL, 0);
 225         if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
 226                 bb_perror_msg_and_die("shmat");
 227         }
 228
 229         memset(G.shbuf, 0, G.shm_size);
 230         G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
 231         /*G.shbuf->tail = 0;*/
 232
 233         // we'll trust the OS to set initial semval to 0 (let's hope)
 234         G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
 235         if (G.s_semid == -1) {
 236                 if (errno == EEXIST) {
 237                         G.s_semid = semget(KEY_ID, 2, 0);
 238                         if (G.s_semid != -1)
 239                                 return;
 240                 }
 241                 bb_perror_msg_and_die("semget");
 242         }
 243 }
 244
 245 /* Write message to shared mem buffer */
 246 static void log_to_shmem(const char *msg, int len)
 247 {
 248         int old_tail, new_tail;
 249
 250         if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 251                 bb_perror_msg_and_die("SMwdn");
 252         }
 253
 254         /* Circular Buffer Algorithm:
 255          * --------------------------
 256          * tail == position where to store next syslog message.
 257          * tail's max value is (shbuf->size - 1)
 258          * Last byte of buffer is never used and remains NUL.
 259          */
 260         len++; /* length with NUL included */
 261  again:
 262         old_tail = G.shbuf->tail;
 263         new_tail = old_tail + len;
 264         if (new_tail < G.shbuf->size) {
 265                 /* store message, set new tail */
 266                 memcpy(G.shbuf->data + old_tail, msg, len);
 267                 G.shbuf->tail = new_tail;
 268         } else {
 269                 /* k == available buffer space ahead of old tail */
 270                 int k = G.shbuf->size - old_tail;
 271                 /* copy what fits to the end of buffer, and repeat */
 272                 memcpy(G.shbuf->data + old_tail, msg, k);
 273                 msg += k;
 274                 len -= k;
 275                 G.shbuf->tail = 0;
 276                 goto again;
 277         }
 278         if (semop(G.s_semid, G.SMwup, 1) == -1) {
 279                 bb_perror_msg_and_die("SMwup");
 280         }
 281         if (DEBUG)
 282                 printf("tail:%d\n", G.shbuf->tail);
 283 }
 284 #else
 285 void ipcsyslog_cleanup(void);
 286 void ipcsyslog_init(void);
 287 void log_to_shmem(const char *msg);
 288 #endif /* FEATURE_IPC_SYSLOG */
 289
 290
 291 /* Print a message to the log file. */
 292 static void log_locally(time_t now, char *msg)
 293 {
 294         struct flock fl;
 295         int len = strlen(msg);
 296
 297 #if ENABLE_FEATURE_IPC_SYSLOG
 298         if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 299                 log_to_shmem(msg, len);
 300                 return;
 301         }
 302 #endif
 303         if (G.logFD >= 0) {
 304                 if (!now)
 305                         now = time(NULL);
 306                 if (G.last_log_time != now) {
 307                         G.last_log_time = now; /* reopen log file every second */
 308                         close(G.logFD);
 309                         goto reopen;
 310                 }
 311         } else {
 312  reopen:
 313                 G.logFD = device_open(G.logFilePath, O_WRONLY | O_CREAT
 314                                         | O_NOCTTY | O_APPEND | O_NONBLOCK);
 315                 if (G.logFD < 0) {
 316                         /* cannot open logfile? - print to /dev/console then */
 317                         int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
 318                         if (fd < 0)
 319                                 fd = 2; /* then stderr, dammit */
 320                         full_write(fd, msg, len);
 321                         if (fd != 2)
 322                                 close(fd);
 323                         return;
 324                 }
 325 #if ENABLE_FEATURE_ROTATE_LOGFILE
 326                 {
 327                         struct stat statf;
 328                         G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode));
 329                         /* bug (mostly harmless): can wrap around if file > 4gb */
 330                         G.curFileSize = statf.st_size;
 331                 }
 332 #endif
 333         }
 334
 335         fl.l_whence = SEEK_SET;
 336         fl.l_start = 0;
 337         fl.l_len = 1;
 338         fl.l_type = F_WRLCK;
 339         fcntl(G.logFD, F_SETLKW, &fl);
 340
 341 #if ENABLE_FEATURE_ROTATE_LOGFILE
 342         if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) {
 343                 if (G.logFileRotate) { /* always 0..99 */
 344                         int i = strlen(G.logFilePath) + 3 + 1;
 345                         char oldFile[i];
 346                         char newFile[i];
 347                         i = G.logFileRotate - 1;
 348                         /* rename: f.8 -> f.9; f.7 -> f.8; ... */
 349                         while (1) {
 350                                 sprintf(newFile, "%s.%d", G.logFilePath, i);
 351                                 if (i == 0) break;
 352                                 sprintf(oldFile, "%s.%d", G.logFilePath, --i);
 353                                 /* ignore errors - file might be missing */
 354                                 rename(oldFile, newFile);
 355                         }
 356                         /* newFile == "f.0" now */
 357                         rename(G.logFilePath, newFile);
 358                         fl.l_type = F_UNLCK;
 359                         fcntl(G.logFD, F_SETLKW, &fl);
 360                         close(G.logFD);
 361                         goto reopen;
 362                 }
 363                 ftruncate(G.logFD, 0);
 364         }
 365         G.curFileSize +=
 366 #endif
 367                         full_write(G.logFD, msg, len);
 368         fl.l_type = F_UNLCK;
 369         fcntl(G.logFD, F_SETLKW, &fl);
 370 }
 371
 372 static void parse_fac_prio_20(int pri, char *res20)
 373 {
 374         const CODE *c_pri, *c_fac;
 375
 376         if (pri != 0) {
 377                 c_fac = facilitynames;
 378                 while (c_fac->c_name) {
 379                         if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
 380                                 c_fac++;
 381                                 continue;
 382                         }
 383                         /* facility is found, look for prio */
 384                         c_pri = prioritynames;
 385                         while (c_pri->c_name) {
 386                                 if (c_pri->c_val != LOG_PRI(pri)) {
 387                                         c_pri++;
 388                                         continue;
 389                                 }
 390                                 snprintf(res20, 20, "%s.%s",
 391                                                 c_fac->c_name, c_pri->c_name);
 392                                 return;
 393                         }
 394                         /* prio not found, bail out */
 395                         break;
 396                 }
 397                 snprintf(res20, 20, "<%d>", pri);
 398         }
 399 }
 400
 401 /* len parameter is used only for "is there a timestamp?" check.
 402  * NB: some callers cheat and supply len==0 when they know
 403  * that there is no timestamp, short-circuiting the test. */
 404 static void timestamp_and_log(int pri, char *msg, int len)
 405 {
 406         char *timestamp;
 407         time_t now;
 408
 409         if (len < 16 || msg[3] != ' ' || msg[6] != ' '
 410          || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
 411         ) {
 412                 time(&now);
 413                 timestamp = ctime(&now) + 4; /* skip day of week */
 414         } else {
 415                 now = 0;
 416                 timestamp = msg;
 417                 msg += 16;
 418         }
 419         timestamp[15] = '\0';
 420
 421         if (option_mask32 & OPT_small)
 422                 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
 423         else {
 424                 char res[20];
 425                 parse_fac_prio_20(pri, res);
 426                 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
 427         }
 428
 429         /* Log message locally (to file or shared mem) */
 430         log_locally(now, G.printbuf);
 431 }
 432
 433 static void timestamp_and_log_internal(const char *msg)
 434 {
 435         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
 436                 return;
 437         timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
 438 }
 439
 440 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
 441  * embedded NULs. Split messages on each of these NULs, parse prio,
 442  * escape control chars and log each locally. */
 443 static void split_escape_and_log(char *tmpbuf, int len)
 444 {
 445         char *p = tmpbuf;
 446
 447         tmpbuf += len;
 448         while (p < tmpbuf) {
 449                 char c;
 450                 char *q = G.parsebuf;
 451                 int pri = (LOG_USER | LOG_NOTICE);
 452
 453                 if (*p == '<') {
 454                         /* Parse the magic priority number */
 455                         pri = bb_strtou(p + 1, &p, 10);
 456                         if (*p == '>')
 457                                 p++;
 458                         if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 459                                 pri = (LOG_USER | LOG_NOTICE);
 460                 }
 461
 462                 while ((c = *p++)) {
 463                         if (c == '\n')
 464                                 c = ' ';
 465                         if (!(c & ~0x1f) && c != '\t') {
 466                                 *q++ = '^';
 467                                 c += '@'; /* ^@, ^A, ^B... */
 468                         }
 469                         *q++ = c;
 470                 }
 471                 *q = '\0';
 472
 473                 /* Now log it */
 474                 if (LOG_PRI(pri) < G.logLevel)
 475                         timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
 476         }
 477 }
 478
 479 static void quit_signal(int sig)
 480 {
 481         timestamp_and_log_internal("syslogd exiting");
 482         puts("syslogd exiting");
 483         if (ENABLE_FEATURE_IPC_SYSLOG)
 484                 ipcsyslog_cleanup();
 485         kill_myself_with_sig(sig);
 486 }
 487
 488 #ifdef SYSLOGD_MARK
 489 static void do_mark(int sig)
 490 {
 491         if (G.markInterval) {
 492                 timestamp_and_log_internal("-- MARK --");
 493                 alarm(G.markInterval);
 494         }
 495 }
 496 #endif
 497
 498 /* Don't inline: prevent struct sockaddr_un to take up space on stack
 499  * permanently */
 500 static NOINLINE int create_socket(void)
 501 {
 502         struct sockaddr_un sunx;
 503         int sock_fd;
 504         char *dev_log_name;
 505
 506         memset(&sunx, 0, sizeof(sunx));
 507         sunx.sun_family = AF_UNIX;
 508
 509         /* Unlink old /dev/log or object it points to. */
 510         /* (if it exists, bind will fail) */
 511         strcpy(sunx.sun_path, "/dev/log");
 512         dev_log_name = xmalloc_follow_symlinks("/dev/log");
 513         if (dev_log_name) {
 514                 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
 515                 free(dev_log_name);
 516         }
 517         unlink(sunx.sun_path);
 518
 519         sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
 520         xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
 521         chmod("/dev/log", 0666);
 522
 523         return sock_fd;
 524 }
 525
 526 #if ENABLE_FEATURE_REMOTE_LOG
 527 static int try_to_resolve_remote(void)
 528 {
 529         if (!G.remoteAddr) {
 530                 unsigned now = monotonic_sec();
 531
 532                 /* Don't resolve name too often - DNS timeouts can be big */
 533                 if ((now - G.last_dns_resolve) < DNS_WAIT_SEC)
 534                         return -1;
 535                 G.last_dns_resolve = now;
 536                 G.remoteAddr = host2sockaddr(G.remoteAddrStr, 514);
 537                 if (!G.remoteAddr)
 538                         return -1;
 539         }
 540         return socket(G.remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
 541 }
 542 #endif
 543
 544 static void do_syslogd(void) NORETURN;
 545 static void do_syslogd(void)
 546 {
 547         int sock_fd;
 548 #if ENABLE_FEATURE_SYSLOGD_DUP
 549         int last_sz = -1;
 550         char *last_buf;
 551         char *recvbuf = G.recvbuf;
 552 #else
 553 #define recvbuf (G.recvbuf)
 554 #endif
 555
 556         /* Set up signal handlers */
 557         bb_signals(0
 558                 + (1 << SIGINT)
 559                 + (1 << SIGTERM)
 560                 + (1 << SIGQUIT)
 561                 , quit_signal);
 562         signal(SIGHUP, SIG_IGN);
 563         /* signal(SIGCHLD, SIG_IGN); - why? */
 564 #ifdef SYSLOGD_MARK
 565         signal(SIGALRM, do_mark);
 566         alarm(G.markInterval);
 567 #endif
 568         sock_fd = create_socket();
 569
 570         if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
 571                 ipcsyslog_init();
 572         }
 573
 574         timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
 575
 576         for (;;) {
 577                 ssize_t sz;
 578
 579 #if ENABLE_FEATURE_SYSLOGD_DUP
 580                 last_buf = recvbuf;
 581                 if (recvbuf == G.recvbuf)
 582                         recvbuf = G.recvbuf + MAX_READ;
 583                 else
 584                         recvbuf = G.recvbuf;
 585 #endif
 586  read_again:
 587                 sz = safe_read(sock_fd, recvbuf, MAX_READ - 1);
 588                 if (sz < 0)
 589                         bb_perror_msg_and_die("read from /dev/log");
 590
 591                 /* Drop trailing '\n' and NULs (typically there is one NUL) */
 592                 while (1) {
 593                         if (sz == 0)
 594                                 goto read_again;
 595                         /* man 3 syslog says: "A trailing newline is added when needed".
 596                          * However, neither glibc nor uclibc do this:
 597                          * syslog(prio, "test")   sends "test\0" to /dev/log,
 598                          * syslog(prio, "test\n") sends "test\n\0".
 599                          * IOW: newline is passed verbatim!
 600                          * I take it to mean that it's syslogd's job
 601                          * to make those look identical in the log files. */
 602                         if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
 603                                 break;
 604                         sz--;
 605                 }
 606 #if ENABLE_FEATURE_SYSLOGD_DUP
 607                 if ((option_mask32 & OPT_dup) && (sz == last_sz))
 608                         if (memcmp(last_buf, recvbuf, sz) == 0)
 609                                 continue;
 610                 last_sz = sz;
 611 #endif
 612 #if ENABLE_FEATURE_REMOTE_LOG
 613                 /* We are not modifying log messages in any way before send */
 614                 /* Remote site cannot trust _us_ anyway and need to do validation again */
 615                 if (G.remoteAddrStr) {
 616                         if (-1 == G.remoteFD) {
 617                                 G.remoteFD = try_to_resolve_remote();
 618                                 if (-1 == G.remoteFD)
 619                                         goto no_luck;
 620                         }
 621                         /* Stock syslogd sends it '\n'-terminated
 622                          * over network, mimic that */
 623                         recvbuf[sz] = '\n';
 624                         /* send message to remote logger, ignore possible error */
 625                         /* TODO: on some errors, close and set G.remoteFD to -1
 626                          * so that DNS resolution and connect is retried? */
 627                         sendto(G.remoteFD, recvbuf, sz+1, MSG_DONTWAIT,
 628                                     &G.remoteAddr->u.sa, G.remoteAddr->len);
 629  no_luck: ;
 630                 }
 631 #endif
 632                 if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
 633                         recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
 634                         split_escape_and_log(recvbuf, sz);
 635                 }
 636         } /* for (;;) */
 637 #undef recvbuf
 638 }
 639
 640 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 641 int syslogd_main(int argc UNUSED_PARAM, char **argv)
 642 {
 643         char OPTION_DECL;
 644
 645         INIT_G();
 646 #if ENABLE_FEATURE_REMOTE_LOG
 647         G.last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
 648 #endif
 649
 650         /* do normal option parsing */
 651         opt_complementary = "=0"; /* no non-option params */
 652         getopt32(argv, OPTION_STR, OPTION_PARAM);
 653 #ifdef SYSLOGD_MARK
 654         if (option_mask32 & OPT_mark) // -m
 655                 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
 656 #endif
 657         //if (option_mask32 & OPT_nofork) // -n
 658         //if (option_mask32 & OPT_outfile) // -O
 659         if (option_mask32 & OPT_loglevel) // -l
 660                 G.logLevel = xatou_range(opt_l, 1, 8);
 661         //if (option_mask32 & OPT_small) // -S
 662 #if ENABLE_FEATURE_ROTATE_LOGFILE
 663         if (option_mask32 & OPT_filesize) // -s
 664                 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
 665         if (option_mask32 & OPT_rotatecnt) // -b
 666                 G.logFileRotate = xatou_range(opt_b, 0, 99);
 667 #endif
 668 #if ENABLE_FEATURE_IPC_SYSLOG
 669         if (opt_C) // -Cn
 670                 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
 671 #endif
 672
 673         /* If they have not specified remote logging, then log locally */
 674         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_remotelog))
 675                 option_mask32 |= OPT_locallog;
 676
 677         /* Store away localhost's name before the fork */
 678         G.hostname = safe_gethostname();
 679         *strchrnul(G.hostname, '.') = '\0';
 680
 681         if (!(option_mask32 & OPT_nofork)) {
 682                 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
 683         }
 684         umask(0);
 685         write_pidfile("/var/run/syslogd.pid");
 686         do_syslogd();
 687         /* return EXIT_SUCCESS; */
 688 }
 689
 690 /* Clean up. Needed because we are included from syslogd_and_logger.c */
 691 #undef G
 692 #undef GLOBALS
 693 #undef INIT_G
 694 #undef OPTION_STR
 695 #undef OPTION_DECL
 696 #undef OPTION_PARAM