busybox/sysklogd/syslogd.c
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   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 GPLv2 or later, see file LICENSE in this source tree.
  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 <sys/un.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/* Write locking does not seem to be useful either */
  46#undef SYSLOGD_WRLOCK
  47
  48enum {
  49        MAX_READ = CONFIG_FEATURE_SYSLOGD_READ_BUFFER_SIZE,
  50        DNS_WAIT_SEC = 2 * 60,
  51};
  52
  53/* Semaphore operation structures */
  54struct shbuf_ds {
  55        int32_t size;   /* size of data - 1 */
  56        int32_t tail;   /* end of message list */
  57        char data[1];   /* data/messages */
  58};
  59
  60#if ENABLE_FEATURE_REMOTE_LOG
  61typedef struct {
  62        int remoteFD;
  63        unsigned last_dns_resolve;
  64        len_and_sockaddr *remoteAddr;
  65        const char *remoteHostname;
  66} remoteHost_t;
  67#endif
  68
  69/* Allows us to have smaller initializer. Ugly. */
  70#define GLOBALS \
  71        const char *logFilePath;                \
  72        int logFD;                              \
  73        /* interval between marks in seconds */ \
  74        /*int markInterval;*/                   \
  75        /* level of messages to be logged */    \
  76        int logLevel;                           \
  77IF_FEATURE_ROTATE_LOGFILE( \
  78        /* max size of file before rotation */  \
  79        unsigned logFileSize;                   \
  80        /* number of rotated message files */   \
  81        unsigned logFileRotate;                 \
  82        unsigned curFileSize;                   \
  83        smallint isRegular;                     \
  84) \
  85IF_FEATURE_IPC_SYSLOG( \
  86        int shmid; /* ipc shared memory id */   \
  87        int s_semid; /* ipc semaphore id */     \
  88        int shm_size;                           \
  89        struct sembuf SMwup[1];                 \
  90        struct sembuf SMwdn[3];                 \
  91)
  92
  93struct init_globals {
  94        GLOBALS
  95};
  96
  97struct globals {
  98        GLOBALS
  99
 100#if ENABLE_FEATURE_REMOTE_LOG
 101        llist_t *remoteHosts;
 102#endif
 103#if ENABLE_FEATURE_IPC_SYSLOG
 104        struct shbuf_ds *shbuf;
 105#endif
 106        time_t last_log_time;
 107        /* localhost's name. We print only first 64 chars */
 108        char *hostname;
 109
 110        /* We recv into recvbuf... */
 111        char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
 112        /* ...then copy to parsebuf, escaping control chars */
 113        /* (can grow x2 max) */
 114        char parsebuf[MAX_READ*2];
 115        /* ...then sprintf into printbuf, adding timestamp (15 chars),
 116         * host (64), fac.prio (20) to the message */
 117        /* (growth by: 15 + 64 + 20 + delims = ~110) */
 118        char printbuf[MAX_READ*2 + 128];
 119};
 120
 121static const struct init_globals init_data = {
 122        .logFilePath = "/var/log/messages",
 123        .logFD = -1,
 124#ifdef SYSLOGD_MARK
 125        .markInterval = 20 * 60,
 126#endif
 127        .logLevel = 8,
 128#if ENABLE_FEATURE_ROTATE_LOGFILE
 129        .logFileSize = 200 * 1024,
 130        .logFileRotate = 1,
 131#endif
 132#if ENABLE_FEATURE_IPC_SYSLOG
 133        .shmid = -1,
 134        .s_semid = -1,
 135        .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), // default shm size
 136        .SMwup = { {1, -1, IPC_NOWAIT} },
 137        .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
 138#endif
 139};
 140
 141#define G (*ptr_to_globals)
 142#define INIT_G() do { \
 143        SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
 144} while (0)
 145
 146
 147/* Options */
 148enum {
 149        OPTBIT_mark = 0, // -m
 150        OPTBIT_nofork, // -n
 151        OPTBIT_outfile, // -O
 152        OPTBIT_loglevel, // -l
 153        OPTBIT_small, // -S
 154        IF_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,)  // -s
 155        IF_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,)  // -b
 156        IF_FEATURE_REMOTE_LOG(    OPTBIT_remotelog  ,)  // -R
 157        IF_FEATURE_REMOTE_LOG(    OPTBIT_locallog   ,)  // -L
 158        IF_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,)  // -C
 159        IF_FEATURE_SYSLOGD_DUP(   OPTBIT_dup        ,)  // -D
 160
 161        OPT_mark        = 1 << OPTBIT_mark    ,
 162        OPT_nofork      = 1 << OPTBIT_nofork  ,
 163        OPT_outfile     = 1 << OPTBIT_outfile ,
 164        OPT_loglevel    = 1 << OPTBIT_loglevel,
 165        OPT_small       = 1 << OPTBIT_small   ,
 166        OPT_filesize    = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
 167        OPT_rotatecnt   = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
 168        OPT_remotelog   = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remotelog  )) + 0,
 169        OPT_locallog    = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_locallog   )) + 0,
 170        OPT_circularlog = IF_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
 171        OPT_dup         = IF_FEATURE_SYSLOGD_DUP(   (1 << OPTBIT_dup        )) + 0,
 172};
 173#define OPTION_STR "m:nO:l:S" \
 174        IF_FEATURE_ROTATE_LOGFILE("s:" ) \
 175        IF_FEATURE_ROTATE_LOGFILE("b:" ) \
 176        IF_FEATURE_REMOTE_LOG(    "R:" ) \
 177        IF_FEATURE_REMOTE_LOG(    "L"  ) \
 178        IF_FEATURE_IPC_SYSLOG(    "C::") \
 179        IF_FEATURE_SYSLOGD_DUP(   "D"  )
 180#define OPTION_DECL *opt_m, *opt_l \
 181        IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \
 182        IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \
 183        IF_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL)
 184#define OPTION_PARAM &opt_m, &G.logFilePath, &opt_l \
 185        IF_FEATURE_ROTATE_LOGFILE(,&opt_s) \
 186        IF_FEATURE_ROTATE_LOGFILE(,&opt_b) \
 187        IF_FEATURE_REMOTE_LOG(    ,&remoteAddrList) \
 188        IF_FEATURE_IPC_SYSLOG(    ,&opt_C)
 189
 190
 191/* circular buffer variables/structures */
 192#if ENABLE_FEATURE_IPC_SYSLOG
 193
 194#if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
 195#error Sorry, you must set the syslogd buffer size to at least 4KB.
 196#error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 197#endif
 198
 199/* our shared key (syslogd.c and logread.c must be in sync) */
 200enum { KEY_ID = 0x414e4547 }; /* "GENA" */
 201
 202static void ipcsyslog_cleanup(void)
 203{
 204        if (G.shmid != -1) {
 205                shmdt(G.shbuf);
 206        }
 207        if (G.shmid != -1) {
 208                shmctl(G.shmid, IPC_RMID, NULL);
 209        }
 210        if (G.s_semid != -1) {
 211                semctl(G.s_semid, 0, IPC_RMID, 0);
 212        }
 213}
 214
 215static void ipcsyslog_init(void)
 216{
 217        if (DEBUG)
 218                printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
 219
 220        G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
 221        if (G.shmid == -1) {
 222                bb_perror_msg_and_die("shmget");
 223        }
 224
 225        G.shbuf = shmat(G.shmid, NULL, 0);
 226        if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
 227                bb_perror_msg_and_die("shmat");
 228        }
 229
 230        memset(G.shbuf, 0, G.shm_size);
 231        G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
 232        /*G.shbuf->tail = 0;*/
 233
 234        // we'll trust the OS to set initial semval to 0 (let's hope)
 235        G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
 236        if (G.s_semid == -1) {
 237                if (errno == EEXIST) {
 238                        G.s_semid = semget(KEY_ID, 2, 0);
 239                        if (G.s_semid != -1)
 240                                return;
 241                }
 242                bb_perror_msg_and_die("semget");
 243        }
 244}
 245
 246/* Write message to shared mem buffer */
 247static void log_to_shmem(const char *msg, int len)
 248{
 249        int old_tail, new_tail;
 250
 251        if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 252                bb_perror_msg_and_die("SMwdn");
 253        }
 254
 255        /* Circular Buffer Algorithm:
 256         * --------------------------
 257         * tail == position where to store next syslog message.
 258         * tail's max value is (shbuf->size - 1)
 259         * Last byte of buffer is never used and remains NUL.
 260         */
 261        len++; /* length with NUL included */
 262 again:
 263        old_tail = G.shbuf->tail;
 264        new_tail = old_tail + len;
 265        if (new_tail < G.shbuf->size) {
 266                /* store message, set new tail */
 267                memcpy(G.shbuf->data + old_tail, msg, len);
 268                G.shbuf->tail = new_tail;
 269        } else {
 270                /* k == available buffer space ahead of old tail */
 271                int k = G.shbuf->size - old_tail;
 272                /* copy what fits to the end of buffer, and repeat */
 273                memcpy(G.shbuf->data + old_tail, msg, k);
 274                msg += k;
 275                len -= k;
 276                G.shbuf->tail = 0;
 277                goto again;
 278        }
 279        if (semop(G.s_semid, G.SMwup, 1) == -1) {
 280                bb_perror_msg_and_die("SMwup");
 281        }
 282        if (DEBUG)
 283                printf("tail:%d\n", G.shbuf->tail);
 284}
 285#else
 286void ipcsyslog_cleanup(void);
 287void ipcsyslog_init(void);
 288void log_to_shmem(const char *msg);
 289#endif /* FEATURE_IPC_SYSLOG */
 290
 291
 292/* Print a message to the log file. */
 293static void log_locally(time_t now, char *msg)
 294{
 295#ifdef SYSLOGD_WRLOCK
 296        struct flock fl;
 297#endif
 298        int len = strlen(msg);
 299
 300#if ENABLE_FEATURE_IPC_SYSLOG
 301        if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 302                log_to_shmem(msg, len);
 303                return;
 304        }
 305#endif
 306        if (G.logFD >= 0) {
 307                /* Reopen log file every second. This allows admin
 308                 * to delete the file and not worry about restarting us.
 309                 * This costs almost nothing since it happens
 310                 * _at most_ once a second.
 311                 */
 312                if (!now)
 313                        now = time(NULL);
 314                if (G.last_log_time != now) {
 315                        G.last_log_time = now;
 316                        close(G.logFD);
 317                        goto reopen;
 318                }
 319        } else {
 320 reopen:
 321                G.logFD = open(G.logFilePath, O_WRONLY | O_CREAT
 322                                        | O_NOCTTY | O_APPEND | O_NONBLOCK,
 323                                        0666);
 324                if (G.logFD < 0) {
 325                        /* cannot open logfile? - print to /dev/console then */
 326                        int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
 327                        if (fd < 0)
 328                                fd = 2; /* then stderr, dammit */
 329                        full_write(fd, msg, len);
 330                        if (fd != 2)
 331                                close(fd);
 332                        return;
 333                }
 334#if ENABLE_FEATURE_ROTATE_LOGFILE
 335                {
 336                        struct stat statf;
 337                        G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode));
 338                        /* bug (mostly harmless): can wrap around if file > 4gb */
 339                        G.curFileSize = statf.st_size;
 340                }
 341#endif
 342        }
 343
 344#ifdef SYSLOGD_WRLOCK
 345        fl.l_whence = SEEK_SET;
 346        fl.l_start = 0;
 347        fl.l_len = 1;
 348        fl.l_type = F_WRLCK;
 349        fcntl(G.logFD, F_SETLKW, &fl);
 350#endif
 351
 352#if ENABLE_FEATURE_ROTATE_LOGFILE
 353        if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) {
 354                if (G.logFileRotate) { /* always 0..99 */
 355                        int i = strlen(G.logFilePath) + 3 + 1;
 356                        char oldFile[i];
 357                        char newFile[i];
 358                        i = G.logFileRotate - 1;
 359                        /* rename: f.8 -> f.9; f.7 -> f.8; ... */
 360                        while (1) {
 361                                sprintf(newFile, "%s.%d", G.logFilePath, i);
 362                                if (i == 0) break;
 363                                sprintf(oldFile, "%s.%d", G.logFilePath, --i);
 364                                /* ignore errors - file might be missing */
 365                                rename(oldFile, newFile);
 366                        }
 367                        /* newFile == "f.0" now */
 368                        rename(G.logFilePath, newFile);
 369#ifdef SYSLOGD_WRLOCK
 370                        fl.l_type = F_UNLCK;
 371                        fcntl(G.logFD, F_SETLKW, &fl);
 372#endif
 373                        close(G.logFD);
 374                        goto reopen;
 375                }
 376                ftruncate(G.logFD, 0);
 377        }
 378        G.curFileSize +=
 379#endif
 380                        full_write(G.logFD, msg, len);
 381#ifdef SYSLOGD_WRLOCK
 382        fl.l_type = F_UNLCK;
 383        fcntl(G.logFD, F_SETLKW, &fl);
 384#endif
 385}
 386
 387static void parse_fac_prio_20(int pri, char *res20)
 388{
 389        const CODE *c_pri, *c_fac;
 390
 391        if (pri != 0) {
 392                c_fac = facilitynames;
 393                while (c_fac->c_name) {
 394                        if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
 395                                c_fac++;
 396                                continue;
 397                        }
 398                        /* facility is found, look for prio */
 399                        c_pri = prioritynames;
 400                        while (c_pri->c_name) {
 401                                if (c_pri->c_val != LOG_PRI(pri)) {
 402                                        c_pri++;
 403                                        continue;
 404                                }
 405                                snprintf(res20, 20, "%s.%s",
 406                                                c_fac->c_name, c_pri->c_name);
 407                                return;
 408                        }
 409                        /* prio not found, bail out */
 410                        break;
 411                }
 412                snprintf(res20, 20, "<%d>", pri);
 413        }
 414}
 415
 416/* len parameter is used only for "is there a timestamp?" check.
 417 * NB: some callers cheat and supply len==0 when they know
 418 * that there is no timestamp, short-circuiting the test. */
 419static void timestamp_and_log(int pri, char *msg, int len)
 420{
 421        char *timestamp;
 422        time_t now;
 423
 424        /* Jan 18 00:11:22 msg... */
 425        /* 01234567890123456 */
 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
 450static 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. */
 461static 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
 498static 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 */
 509static 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
 536static int try_to_resolve_remote(remoteHost_t *rh)
 537{
 538        if (!rh->remoteAddr) {
 539                unsigned now = monotonic_sec();
 540
 541                /* Don't resolve name too often - DNS timeouts can be big */
 542                if ((now - rh->last_dns_resolve) < DNS_WAIT_SEC)
 543                        return -1;
 544                rh->last_dns_resolve = now;
 545                rh->remoteAddr = host2sockaddr(rh->remoteHostname, 514);
 546                if (!rh->remoteAddr)
 547                        return -1;
 548        }
 549        return xsocket(rh->remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
 550}
 551#endif
 552
 553static void do_syslogd(void) NORETURN;
 554static void do_syslogd(void)
 555{
 556        int sock_fd;
 557#if ENABLE_FEATURE_REMOTE_LOG
 558        llist_t *item;
 559#endif
 560#if ENABLE_FEATURE_SYSLOGD_DUP
 561        int last_sz = -1;
 562        char *last_buf;
 563        char *recvbuf = G.recvbuf;
 564#else
 565#define recvbuf (G.recvbuf)
 566#endif
 567
 568        /* Set up signal handlers (so that they interrupt read()) */
 569        signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo);
 570        signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
 571        //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo);
 572        signal(SIGHUP, SIG_IGN);
 573#ifdef SYSLOGD_MARK
 574        signal(SIGALRM, do_mark);
 575        alarm(G.markInterval);
 576#endif
 577        sock_fd = create_socket();
 578
 579        if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
 580                ipcsyslog_init();
 581        }
 582
 583        timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
 584
 585        while (!bb_got_signal) {
 586                ssize_t sz;
 587
 588#if ENABLE_FEATURE_SYSLOGD_DUP
 589                last_buf = recvbuf;
 590                if (recvbuf == G.recvbuf)
 591                        recvbuf = G.recvbuf + MAX_READ;
 592                else
 593                        recvbuf = G.recvbuf;
 594#endif
 595 read_again:
 596                sz = read(sock_fd, recvbuf, MAX_READ - 1);
 597                if (sz < 0) {
 598                        if (!bb_got_signal)
 599                                bb_perror_msg("read from /dev/log");
 600                        break;
 601                }
 602
 603                /* Drop trailing '\n' and NULs (typically there is one NUL) */
 604                while (1) {
 605                        if (sz == 0)
 606                                goto read_again;
 607                        /* man 3 syslog says: "A trailing newline is added when needed".
 608                         * However, neither glibc nor uclibc do this:
 609                         * syslog(prio, "test")   sends "test\0" to /dev/log,
 610                         * syslog(prio, "test\n") sends "test\n\0".
 611                         * IOW: newline is passed verbatim!
 612                         * I take it to mean that it's syslogd's job
 613                         * to make those look identical in the log files. */
 614                        if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
 615                                break;
 616                        sz--;
 617                }
 618#if ENABLE_FEATURE_SYSLOGD_DUP
 619                if ((option_mask32 & OPT_dup) && (sz == last_sz))
 620                        if (memcmp(last_buf, recvbuf, sz) == 0)
 621                                continue;
 622                last_sz = sz;
 623#endif
 624#if ENABLE_FEATURE_REMOTE_LOG
 625                /* Stock syslogd sends it '\n'-terminated
 626                 * over network, mimic that */
 627                recvbuf[sz] = '\n';
 628
 629                /* We are not modifying log messages in any way before send */
 630                /* Remote site cannot trust _us_ anyway and need to do validation again */
 631                for (item = G.remoteHosts; item != NULL; item = item->link) {
 632                        remoteHost_t *rh = (remoteHost_t *)item->data;
 633
 634                        if (rh->remoteFD == -1) {
 635                                rh->remoteFD = try_to_resolve_remote(rh);
 636                                if (rh->remoteFD == -1)
 637                                        continue;
 638                        }
 639
 640                        /* Send message to remote logger.
 641                         * On some errors, close and set remoteFD to -1
 642                         * so that DNS resolution is retried.
 643                         */
 644                        if (sendto(rh->remoteFD, recvbuf, sz+1,
 645                                        MSG_DONTWAIT | MSG_NOSIGNAL,
 646                                        &(rh->remoteAddr->u.sa), rh->remoteAddr->len) == -1
 647                        ) {
 648                                switch (errno) {
 649                                case ECONNRESET:
 650                                case ENOTCONN: /* paranoia */
 651                                case EPIPE:
 652                                        close(rh->remoteFD);
 653                                        rh->remoteFD = -1;
 654                                        free(rh->remoteAddr);
 655                                        rh->remoteAddr = NULL;
 656                                }
 657                        }
 658                }
 659#endif
 660                if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
 661                        recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
 662                        split_escape_and_log(recvbuf, sz);
 663                }
 664        } /* while (!bb_got_signal) */
 665
 666        timestamp_and_log_internal("syslogd exiting");
 667        puts("syslogd exiting");
 668        if (ENABLE_FEATURE_IPC_SYSLOG)
 669                ipcsyslog_cleanup();
 670        kill_myself_with_sig(bb_got_signal);
 671#undef recvbuf
 672}
 673
 674int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 675int syslogd_main(int argc UNUSED_PARAM, char **argv)
 676{
 677        int opts;
 678        char OPTION_DECL;
 679#if ENABLE_FEATURE_REMOTE_LOG
 680        llist_t *remoteAddrList = NULL;
 681#endif
 682
 683        INIT_G();
 684
 685        /* No non-option params, -R can occur multiple times */
 686        opt_complementary = "=0" IF_FEATURE_REMOTE_LOG(":R::");
 687        opts = getopt32(argv, OPTION_STR, OPTION_PARAM);
 688#if ENABLE_FEATURE_REMOTE_LOG
 689        while (remoteAddrList) {
 690                remoteHost_t *rh = xzalloc(sizeof(*rh));
 691                rh->remoteHostname = llist_pop(&remoteAddrList);
 692                rh->remoteFD = -1;
 693                rh->last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
 694                llist_add_to(&G.remoteHosts, rh);
 695        }
 696#endif
 697
 698#ifdef SYSLOGD_MARK
 699        if (opts & OPT_mark) // -m
 700                G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
 701#endif
 702        //if (opts & OPT_nofork) // -n
 703        //if (opts & OPT_outfile) // -O
 704        if (opts & OPT_loglevel) // -l
 705                G.logLevel = xatou_range(opt_l, 1, 8);
 706        //if (opts & OPT_small) // -S
 707#if ENABLE_FEATURE_ROTATE_LOGFILE
 708        if (opts & OPT_filesize) // -s
 709                G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
 710        if (opts & OPT_rotatecnt) // -b
 711                G.logFileRotate = xatou_range(opt_b, 0, 99);
 712#endif
 713#if ENABLE_FEATURE_IPC_SYSLOG
 714        if (opt_C) // -Cn
 715                G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
 716#endif
 717
 718        /* If they have not specified remote logging, then log locally */
 719        if (ENABLE_FEATURE_REMOTE_LOG && !(opts & OPT_remotelog)) // -R
 720                option_mask32 |= OPT_locallog;
 721
 722        /* Store away localhost's name before the fork */
 723        G.hostname = safe_gethostname();
 724        *strchrnul(G.hostname, '.') = '\0';
 725
 726        if (!(opts & OPT_nofork)) {
 727                bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
 728        }
 729        //umask(0); - why??
 730        write_pidfile("/var/run/syslogd.pid");
 731        do_syslogd();
 732        /* return EXIT_SUCCESS; */
 733}
 734
 735/* Clean up. Needed because we are included from syslogd_and_logger.c */
 736#undef DEBUG
 737#undef SYSLOGD_MARK
 738#undef SYSLOGD_WRLOCK
 739#undef G
 740#undef GLOBALS
 741#undef INIT_G
 742#undef OPTION_STR
 743#undef OPTION_DECL
 744#undef OPTION_PARAM
 745