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 GPLv2 or later, see file LICENSE in this source tree.
  14  */
  15 //config:config SYSLOGD
  16 //config:       bool "syslogd (14 kb)"
  17 //config:       default y
  18 //config:       help
  19 //config:       The syslogd utility is used to record logs of all the
  20 //config:       significant events that occur on a system. Every
  21 //config:       message that is logged records the date and time of the
  22 //config:       event, and will generally also record the name of the
  23 //config:       application that generated the message. When used in
  24 //config:       conjunction with klogd, messages from the Linux kernel
  25 //config:       can also be recorded. This is terribly useful,
  26 //config:       especially for finding what happened when something goes
  27 //config:       wrong. And something almost always will go wrong if
  28 //config:       you wait long enough....
  29 //config:
  30 //config:config FEATURE_ROTATE_LOGFILE
  31 //config:       bool "Rotate message files"
  32 //config:       default y
  33 //config:       depends on SYSLOGD
  34 //config:       help
  35 //config:       This enables syslogd to rotate the message files
  36 //config:       on his own. No need to use an external rotate script.
  37 //config:
  38 //config:config FEATURE_REMOTE_LOG
  39 //config:       bool "Remote Log support"
  40 //config:       default y
  41 //config:       depends on SYSLOGD
  42 //config:       help
  43 //config:       When you enable this feature, the syslogd utility can
  44 //config:       be used to send system log messages to another system
  45 //config:       connected via a network. This allows the remote
  46 //config:       machine to log all the system messages, which can be
  47 //config:       terribly useful for reducing the number of serial
  48 //config:       cables you use. It can also be a very good security
  49 //config:       measure to prevent system logs from being tampered with
  50 //config:       by an intruder.
  51 //config:
  52 //config:config FEATURE_SYSLOGD_DUP
  53 //config:       bool "Support -D (drop dups) option"
  54 //config:       default y
  55 //config:       depends on SYSLOGD
  56 //config:       help
  57 //config:       Option -D instructs syslogd to drop consecutive messages
  58 //config:       which are totally the same.
  59 //config:
  60 //config:config FEATURE_SYSLOGD_CFG
  61 //config:       bool "Support syslog.conf"
  62 //config:       default y
  63 //config:       depends on SYSLOGD
  64 //config:       help
  65 //config:       Supports restricted syslogd config. See docs/syslog.conf.txt
  66 //config:
  67 //config:config FEATURE_SYSLOGD_PRECISE_TIMESTAMPS
  68 //config:       bool "Include milliseconds in timestamps"
  69 //config:       default n
  70 //config:       depends on SYSLOGD
  71 //config:       help
  72 //config:       Includes milliseconds (HH:MM:SS.mmm) in timestamp when
  73 //config:       timestamps are added.
  74 //config:
  75 //config:config FEATURE_SYSLOGD_READ_BUFFER_SIZE
  76 //config:       int "Read buffer size in bytes"
  77 //config:       default 256
  78 //config:       range 256 20000
  79 //config:       depends on SYSLOGD
  80 //config:       help
  81 //config:       This option sets the size of the syslog read buffer.
  82 //config:       Actual memory usage increases around five times the
  83 //config:       change done here.
  84 //config:
  85 //config:config FEATURE_IPC_SYSLOG
  86 //config:       bool "Circular Buffer support"
  87 //config:       default y
  88 //config:       depends on SYSLOGD
  89 //config:       help
  90 //config:       When you enable this feature, the syslogd utility will
  91 //config:       use a circular buffer to record system log messages.
  92 //config:       When the buffer is filled it will continue to overwrite
  93 //config:       the oldest messages. This can be very useful for
  94 //config:       systems with little or no permanent storage, since
  95 //config:       otherwise system logs can eventually fill up your
  96 //config:       entire filesystem, which may cause your system to
  97 //config:       break badly.
  98 //config:
  99 //config:config FEATURE_IPC_SYSLOG_BUFFER_SIZE
 100 //config:       int "Circular buffer size in Kbytes (minimum 4KB)"
 101 //config:       default 16
 102 //config:       range 4 2147483647
 103 //config:       depends on FEATURE_IPC_SYSLOG
 104 //config:       help
 105 //config:       This option sets the size of the circular buffer
 106 //config:       used to record system log messages.
 107 //config:
 108 //config:config FEATURE_KMSG_SYSLOG
 109 //config:       bool "Linux kernel printk buffer support"
 110 //config:       default y
 111 //config:       depends on SYSLOGD
 112 //config:       help
 113 //config:       When you enable this feature, the syslogd utility will
 114 //config:       write system log message to the Linux kernel's printk buffer.
 115 //config:       This can be used as a smaller alternative to the syslogd IPC
 116 //config:       support, as klogd and logread aren't needed.
 117 //config:
 118 //config:       NOTICE: Syslog facilities in log entries needs kernel 3.5+.
 119
 120 //applet:IF_SYSLOGD(APPLET(syslogd, BB_DIR_SBIN, BB_SUID_DROP))
 121
 122 //kbuild:lib-$(CONFIG_SYSLOGD) += syslogd_and_logger.o
 123
 124 //usage:#define syslogd_trivial_usage
 125 //usage:       "[OPTIONS]"
 126 //usage:#define syslogd_full_usage "\n\n"
 127 //usage:       "System logging utility\n"
 128 //usage:        IF_NOT_FEATURE_SYSLOGD_CFG(
 129 //usage:       "(this version of syslogd ignores /etc/syslog.conf)\n"
 130 //usage:        )
 131 //usage:     "\n        -n              Run in foreground"
 132 //usage:        IF_FEATURE_REMOTE_LOG(
 133 //usage:     "\n        -R HOST[:PORT]  Log to HOST:PORT (default PORT:514)"
 134 //usage:     "\n        -L              Log locally and via network (default is network only if -R)"
 135 //usage:        )
 136 //usage:        IF_FEATURE_IPC_SYSLOG(
 137 /* NB: -Csize shouldn't have space (because size is optional) */
 138 //usage:     "\n        -C[size_kb]     Log to shared mem buffer (use logread to read it)"
 139 //usage:        )
 140 //usage:        IF_FEATURE_KMSG_SYSLOG(
 141 //usage:     "\n        -K              Log to kernel printk buffer (use dmesg to read it)"
 142 //usage:        )
 143 //usage:     "\n        -O FILE         Log to FILE (default: /var/log/messages, stdout if -)"
 144 //usage:        IF_FEATURE_ROTATE_LOGFILE(
 145 //usage:     "\n        -s SIZE         Max size (KB) before rotation (default 200KB, 0=off)"
 146 //usage:     "\n        -b N            N rotated logs to keep (default 1, max 99, 0=purge)"
 147 //usage:        )
 148 //usage:     "\n        -l N            Log only messages more urgent than prio N (1-8)"
 149 //usage:     "\n        -S              Smaller output"
 150 //usage:     "\n        -t              Strip client-generated timestamps"
 151 //usage:        IF_FEATURE_SYSLOGD_DUP(
 152 //usage:     "\n        -D              Drop duplicates"
 153 //usage:        )
 154 //usage:        IF_FEATURE_SYSLOGD_CFG(
 155 //usage:     "\n        -f FILE         Use FILE as config (default:/etc/syslog.conf)"
 156 //usage:        )
 157 /* //usage:  "\n        -m MIN          Minutes between MARK lines (default 20, 0=off)" */
 158 //usage:
 159 //usage:#define syslogd_example_usage
 160 //usage:       "$ syslogd -R masterlog:514\n"
 161 //usage:       "$ syslogd -R 192.168.1.1:601\n"
 162
 163 /*
 164  * Done in syslogd_and_logger.c:
 165 #include "libbb.h"
 166 #define SYSLOG_NAMES
 167 #define SYSLOG_NAMES_CONST
 168 #include <syslog.h>
 169 */
 170 #ifndef _PATH_LOG
 171 #define _PATH_LOG       "/dev/log"
 172 #endif
 173
 174 #include <sys/un.h>
 175 #include <sys/uio.h>
 176
 177 #if ENABLE_FEATURE_REMOTE_LOG
 178 #include <netinet/in.h>
 179 #endif
 180
 181 #if ENABLE_FEATURE_IPC_SYSLOG
 182 #include <sys/ipc.h>
 183 #include <sys/sem.h>
 184 #include <sys/shm.h>
 185 #endif
 186
 187
 188 #define DEBUG 0
 189
 190 /* MARK code is not very useful, is bloat, and broken:
 191  * can deadlock if alarmed to make MARK while writing to IPC buffer
 192  * (semaphores are down but do_mark routine tries to down them again) */
 193 #undef SYSLOGD_MARK
 194
 195 /* Write locking does not seem to be useful either */
 196 #undef SYSLOGD_WRLOCK
 197
 198 enum {
 199         MAX_READ = CONFIG_FEATURE_SYSLOGD_READ_BUFFER_SIZE,
 200         DNS_WAIT_SEC = 2 * 60,
 201 };
 202
 203 /* Semaphore operation structures */
 204 struct shbuf_ds {
 205         int32_t size;   /* size of data - 1 */
 206         int32_t tail;   /* end of message list */
 207         char data[1];   /* data/messages */
 208 };
 209
 210 #if ENABLE_FEATURE_REMOTE_LOG
 211 typedef struct {
 212         int remoteFD;
 213         unsigned last_dns_resolve;
 214         len_and_sockaddr *remoteAddr;
 215         const char *remoteHostname;
 216 } remoteHost_t;
 217 #endif
 218
 219 typedef struct logFile_t {
 220         const char *path;
 221         int fd;
 222         time_t last_log_time;
 223 #if ENABLE_FEATURE_ROTATE_LOGFILE
 224         unsigned size;
 225         uint8_t isRegular;
 226 #endif
 227 } logFile_t;
 228
 229 #if ENABLE_FEATURE_SYSLOGD_CFG
 230 typedef struct logRule_t {
 231         uint8_t enabled_facility_priomap[LOG_NFACILITIES];
 232         struct logFile_t *file;
 233         struct logRule_t *next;
 234 } logRule_t;
 235 #endif
 236
 237 /* Allows us to have smaller initializer. Ugly. */
 238 #define GLOBALS \
 239         logFile_t logFile;                      \
 240         /* interval between marks in seconds */ \
 241         /*int markInterval;*/                   \
 242         /* level of messages to be logged */    \
 243         int logLevel;                           \
 244 IF_FEATURE_ROTATE_LOGFILE( \
 245         /* max size of file before rotation */  \
 246         unsigned logFileSize;                   \
 247         /* number of rotated message files */   \
 248         unsigned logFileRotate;                 \
 249 ) \
 250 IF_FEATURE_IPC_SYSLOG( \
 251         int shmid; /* ipc shared memory id */   \
 252         int s_semid; /* ipc semaphore id */     \
 253         int shm_size;                           \
 254         struct sembuf SMwup[1];                 \
 255         struct sembuf SMwdn[3];                 \
 256 ) \
 257 IF_FEATURE_SYSLOGD_CFG( \
 258         logRule_t *log_rules; \
 259 ) \
 260 IF_FEATURE_KMSG_SYSLOG( \
 261         int kmsgfd; \
 262         int primask; \
 263 )
 264
 265 struct init_globals {
 266         GLOBALS
 267 };
 268
 269 struct globals {
 270         GLOBALS
 271
 272 #if ENABLE_FEATURE_REMOTE_LOG
 273         llist_t *remoteHosts;
 274 #endif
 275 #if ENABLE_FEATURE_IPC_SYSLOG
 276         struct shbuf_ds *shbuf;
 277 #endif
 278         /* localhost's name. We print only first 64 chars */
 279         char *hostname;
 280
 281         /* We recv into recvbuf... */
 282         char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
 283         /* ...then copy to parsebuf, escaping control chars */
 284         /* (can grow x2 max) */
 285         char parsebuf[MAX_READ*2];
 286         /* ...then sprintf into printbuf, adding timestamp (15 or 19 chars),
 287          * host (64), fac.prio (20) to the message */
 288         /* (growth by: 15 + 64 + 20 + delims = ~110) */
 289         char printbuf[MAX_READ*2 + 128];
 290 };
 291
 292 static const struct init_globals init_data = {
 293         .logFile = {
 294                 .path = "/var/log/messages",
 295                 .fd = -1,
 296         },
 297 #ifdef SYSLOGD_MARK
 298         .markInterval = 20 * 60,
 299 #endif
 300         .logLevel = 8,
 301 #if ENABLE_FEATURE_ROTATE_LOGFILE
 302         .logFileSize = 200 * 1024,
 303         .logFileRotate = 1,
 304 #endif
 305 #if ENABLE_FEATURE_IPC_SYSLOG
 306         .shmid = -1,
 307         .s_semid = -1,
 308         .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), /* default shm size */
 309         .SMwup = { {1, -1, IPC_NOWAIT} },
 310         .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
 311 #endif
 312 };
 313
 314 #define G (*ptr_to_globals)
 315 #define INIT_G() do { \
 316         SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
 317 } while (0)
 318
 319
 320 /* Options */
 321 enum {
 322         OPTBIT_mark = 0, // -m
 323         OPTBIT_nofork, // -n
 324         OPTBIT_outfile, // -O
 325         OPTBIT_loglevel, // -l
 326         OPTBIT_small, // -S
 327         OPTBIT_timestamp, // -t
 328         IF_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,)  // -s
 329         IF_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,)  // -b
 330         IF_FEATURE_REMOTE_LOG(    OPTBIT_remotelog  ,)  // -R
 331         IF_FEATURE_REMOTE_LOG(    OPTBIT_locallog   ,)  // -L
 332         IF_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,)  // -C
 333         IF_FEATURE_SYSLOGD_DUP(   OPTBIT_dup        ,)  // -D
 334         IF_FEATURE_SYSLOGD_CFG(   OPTBIT_cfg        ,)  // -f
 335         IF_FEATURE_KMSG_SYSLOG(   OPTBIT_kmsg       ,)  // -K
 336
 337         OPT_mark        = 1 << OPTBIT_mark    ,
 338         OPT_nofork      = 1 << OPTBIT_nofork  ,
 339         OPT_outfile     = 1 << OPTBIT_outfile ,
 340         OPT_loglevel    = 1 << OPTBIT_loglevel,
 341         OPT_small       = 1 << OPTBIT_small   ,
 342         OPT_timestamp   = 1 << OPTBIT_timestamp,
 343         OPT_filesize    = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
 344         OPT_rotatecnt   = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
 345         OPT_remotelog   = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remotelog  )) + 0,
 346         OPT_locallog    = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_locallog   )) + 0,
 347         OPT_circularlog = IF_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
 348         OPT_dup         = IF_FEATURE_SYSLOGD_DUP(   (1 << OPTBIT_dup        )) + 0,
 349         OPT_cfg         = IF_FEATURE_SYSLOGD_CFG(   (1 << OPTBIT_cfg        )) + 0,
 350         OPT_kmsg        = IF_FEATURE_KMSG_SYSLOG(   (1 << OPTBIT_kmsg       )) + 0,
 351 };
 352 #define OPTION_STR "m:nO:l:St" \
 353         IF_FEATURE_ROTATE_LOGFILE("s:" ) \
 354         IF_FEATURE_ROTATE_LOGFILE("b:" ) \
 355         IF_FEATURE_REMOTE_LOG(    "R:*") \
 356         IF_FEATURE_REMOTE_LOG(    "L"  ) \
 357         IF_FEATURE_IPC_SYSLOG(    "C::") \
 358         IF_FEATURE_SYSLOGD_DUP(   "D"  ) \
 359         IF_FEATURE_SYSLOGD_CFG(   "f:" ) \
 360         IF_FEATURE_KMSG_SYSLOG(   "K"  )
 361 #define OPTION_DECL *opt_m, *opt_l \
 362         IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \
 363         IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \
 364         IF_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL) \
 365         IF_FEATURE_SYSLOGD_CFG(   ,*opt_f = NULL)
 366 #define OPTION_PARAM &opt_m, &(G.logFile.path), &opt_l \
 367         IF_FEATURE_ROTATE_LOGFILE(,&opt_s) \
 368         IF_FEATURE_ROTATE_LOGFILE(,&opt_b) \
 369         IF_FEATURE_REMOTE_LOG(    ,&remoteAddrList) \
 370         IF_FEATURE_IPC_SYSLOG(    ,&opt_C) \
 371         IF_FEATURE_SYSLOGD_CFG(   ,&opt_f)
 372
 373
 374 #if ENABLE_FEATURE_SYSLOGD_CFG
 375 static const CODE* find_by_name(char *name, const CODE* c_set)
 376 {
 377         for (; c_set->c_name; c_set++) {
 378                 if (strcmp(name, c_set->c_name) == 0)
 379                         return c_set;
 380         }
 381         return NULL;
 382 }
 383 #endif
 384 static const CODE* find_by_val(int val, const CODE* c_set)
 385 {
 386         for (; c_set->c_name; c_set++) {
 387                 if (c_set->c_val == val)
 388                         return c_set;
 389         }
 390         return NULL;
 391 }
 392
 393 #if ENABLE_FEATURE_SYSLOGD_CFG
 394 static void parse_syslogdcfg(const char *file)
 395 {
 396         char *t;
 397         logRule_t **pp_rule;
 398         /* tok[0] set of selectors */
 399         /* tok[1] file name */
 400         /* tok[2] has to be NULL */
 401         char *tok[3];
 402         parser_t *parser;
 403
 404         parser = config_open2(file ? file : "/etc/syslog.conf",
 405                                 file ? xfopen_for_read : fopen_for_read);
 406         if (!parser)
 407                 /* didn't find default /etc/syslog.conf */
 408                 /* proceed as if we built busybox without config support */
 409                 return;
 410
 411         /* use ptr to ptr to avoid checking whether head was initialized */
 412         pp_rule = &G.log_rules;
 413         /* iterate through lines of config, skipping comments */
 414         while (config_read(parser, tok, 3, 2, "# \t", PARSE_NORMAL | PARSE_MIN_DIE)) {
 415                 char *cur_selector;
 416                 logRule_t *cur_rule;
 417
 418                 /* unexpected trailing token? */
 419                 if (tok[2])
 420                         goto cfgerr;
 421
 422                 cur_rule = *pp_rule = xzalloc(sizeof(*cur_rule));
 423
 424                 cur_selector = tok[0];
 425                 /* iterate through selectors: "kern.info;kern.!err;..." */
 426                 do {
 427                         const CODE *code;
 428                         char *next_selector;
 429                         uint8_t negated_prio; /* "kern.!err" */
 430                         uint8_t single_prio;  /* "kern.=err" */
 431                         uint32_t facmap; /* bitmap of enabled facilities */
 432                         uint8_t primap;  /* bitmap of enabled priorities */
 433                         unsigned i;
 434
 435                         next_selector = strchr(cur_selector, ';');
 436                         if (next_selector)
 437                                 *next_selector++ = '\0';
 438
 439                         t = strchr(cur_selector, '.');
 440                         if (!t)
 441                                 goto cfgerr;
 442                         *t++ = '\0'; /* separate facility from priority */
 443
 444                         negated_prio = 0;
 445                         single_prio = 0;
 446                         if (*t == '!') {
 447                                 negated_prio = 1;
 448                                 ++t;
 449                         }
 450                         if (*t == '=') {
 451                                 single_prio = 1;
 452                                 ++t;
 453                         }
 454
 455                         /* parse priority */
 456                         if (*t == '*')
 457                                 primap = 0xff; /* all 8 log levels enabled */
 458                         else {
 459                                 uint8_t priority;
 460                                 code = find_by_name(t, bb_prioritynames);
 461                                 if (!code)
 462                                         goto cfgerr;
 463                                 primap = 0;
 464                                 priority = code->c_val;
 465                                 if (priority == INTERNAL_NOPRI) {
 466                                         /* ensure we take "enabled_facility_priomap[fac] &= 0" branch below */
 467                                         negated_prio = 1;
 468                                 } else {
 469                                         priority = 1 << priority;
 470                                         do {
 471                                                 primap |= priority;
 472                                                 if (single_prio)
 473                                                         break;
 474                                                 priority >>= 1;
 475                                         } while (priority);
 476                                         if (negated_prio)
 477                                                 primap = ~primap;
 478                                 }
 479                         }
 480
 481                         /* parse facility */
 482                         if (*cur_selector == '*')
 483                                 facmap = (1<<LOG_NFACILITIES) - 1;
 484                         else {
 485                                 char *next_facility;
 486                                 facmap = 0;
 487                                 t = cur_selector;
 488                                 /* iterate through facilities: "kern,daemon.<priospec>" */
 489                                 do {
 490                                         next_facility = strchr(t, ',');
 491                                         if (next_facility)
 492                                                 *next_facility++ = '\0';
 493                                         code = find_by_name(t, bb_facilitynames);
 494                                         if (!code)
 495                                                 goto cfgerr;
 496                                         /* "mark" is not a real facility, skip it */
 497                                         if (code->c_val != INTERNAL_MARK)
 498                                                 facmap |= 1<<(LOG_FAC(code->c_val));
 499                                         t = next_facility;
 500                                 } while (t);
 501                         }
 502
 503                         /* merge result with previous selectors */
 504                         for (i = 0; i < LOG_NFACILITIES; ++i) {
 505                                 if (!(facmap & (1<<i)))
 506                                         continue;
 507                                 if (negated_prio)
 508                                         cur_rule->enabled_facility_priomap[i] &= primap;
 509                                 else
 510                                         cur_rule->enabled_facility_priomap[i] |= primap;
 511                         }
 512
 513                         cur_selector = next_selector;
 514                 } while (cur_selector);
 515
 516                 /* check whether current file name was mentioned in previous rules or
 517                  * as global logfile (G.logFile).
 518                  */
 519                 if (strcmp(G.logFile.path, tok[1]) == 0) {
 520                         cur_rule->file = &G.logFile;
 521                         goto found;
 522                 }
 523                 /* temporarily use cur_rule as iterator, but *pp_rule still points
 524                  * to currently processing rule entry.
 525                  * NOTE: *pp_rule points to the current (and last in the list) rule.
 526                  */
 527                 for (cur_rule = G.log_rules; cur_rule != *pp_rule; cur_rule = cur_rule->next) {
 528                         if (strcmp(cur_rule->file->path, tok[1]) == 0) {
 529                                 /* found - reuse the same file structure */
 530                                 (*pp_rule)->file = cur_rule->file;
 531                                 cur_rule = *pp_rule;
 532                                 goto found;
 533                         }
 534                 }
 535                 cur_rule->file = xzalloc(sizeof(*cur_rule->file));
 536                 cur_rule->file->fd = -1;
 537                 cur_rule->file->path = xstrdup(tok[1]);
 538  found:
 539                 pp_rule = &cur_rule->next;
 540         }
 541         config_close(parser);
 542         return;
 543
 544  cfgerr:
 545         bb_error_msg_and_die("error in '%s' at line %d",
 546                         file ? file : "/etc/syslog.conf",
 547                         parser->lineno);
 548 }
 549 #endif
 550
 551 /* circular buffer variables/structures */
 552 #if ENABLE_FEATURE_IPC_SYSLOG
 553
 554 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
 555 #error Sorry, you must set the syslogd buffer size to at least 4KB.
 556 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 557 #endif
 558
 559 /* our shared key (syslogd.c and logread.c must be in sync) */
 560 enum { KEY_ID = 0x414e4547 }; /* "GENA" */
 561
 562 static void ipcsyslog_cleanup(void)
 563 {
 564         if (G.shmid != -1) {
 565                 shmdt(G.shbuf);
 566         }
 567         if (G.shmid != -1) {
 568                 shmctl(G.shmid, IPC_RMID, NULL);
 569         }
 570         if (G.s_semid != -1) {
 571                 semctl(G.s_semid, 0, IPC_RMID, 0);
 572         }
 573 }
 574
 575 static void ipcsyslog_init(void)
 576 {
 577         if (DEBUG)
 578                 printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
 579
 580         G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
 581         if (G.shmid == -1) {
 582                 bb_simple_perror_msg_and_die("shmget");
 583         }
 584
 585         G.shbuf = shmat(G.shmid, NULL, 0);
 586         if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
 587                 bb_simple_perror_msg_and_die("shmat");
 588         }
 589
 590         memset(G.shbuf, 0, G.shm_size);
 591         G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
 592         /*G.shbuf->tail = 0;*/
 593
 594         /* we'll trust the OS to set initial semval to 0 (let's hope) */
 595         G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
 596         if (G.s_semid == -1) {
 597                 if (errno == EEXIST) {
 598                         G.s_semid = semget(KEY_ID, 2, 0);
 599                         if (G.s_semid != -1)
 600                                 return;
 601                 }
 602                 bb_simple_perror_msg_and_die("semget");
 603         }
 604 }
 605
 606 /* Write message to shared mem buffer */
 607 static void log_to_shmem(const char *msg)
 608 {
 609         int old_tail, new_tail;
 610         int len;
 611
 612         if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 613                 bb_simple_perror_msg_and_die("SMwdn");
 614         }
 615
 616         /* Circular Buffer Algorithm:
 617          * --------------------------
 618          * tail == position where to store next syslog message.
 619          * tail's max value is (shbuf->size - 1)
 620          * Last byte of buffer is never used and remains NUL.
 621          */
 622         len = strlen(msg) + 1; /* length with NUL included */
 623  again:
 624         old_tail = G.shbuf->tail;
 625         new_tail = old_tail + len;
 626         if (new_tail < G.shbuf->size) {
 627                 /* store message, set new tail */
 628                 memcpy(G.shbuf->data + old_tail, msg, len);
 629                 G.shbuf->tail = new_tail;
 630         } else {
 631                 /* k == available buffer space ahead of old tail */
 632                 int k = G.shbuf->size - old_tail;
 633                 /* copy what fits to the end of buffer, and repeat */
 634                 memcpy(G.shbuf->data + old_tail, msg, k);
 635                 msg += k;
 636                 len -= k;
 637                 G.shbuf->tail = 0;
 638                 goto again;
 639         }
 640         if (semop(G.s_semid, G.SMwup, 1) == -1) {
 641                 bb_simple_perror_msg_and_die("SMwup");
 642         }
 643         if (DEBUG)
 644                 printf("tail:%d\n", G.shbuf->tail);
 645 }
 646 #else
 647 static void ipcsyslog_cleanup(void) {}
 648 static void ipcsyslog_init(void) {}
 649 void log_to_shmem(const char *msg);
 650 #endif /* FEATURE_IPC_SYSLOG */
 651
 652 #if ENABLE_FEATURE_KMSG_SYSLOG
 653 static void kmsg_init(void)
 654 {
 655         G.kmsgfd = xopen("/dev/kmsg", O_WRONLY);
 656
 657         /*
 658          * kernel < 3.5 expects single char printk KERN_* priority prefix,
 659          * from 3.5 onwards the full syslog facility/priority format is supported
 660          */
 661         if (get_linux_version_code() < KERNEL_VERSION(3,5,0))
 662                 G.primask = LOG_PRIMASK;
 663         else
 664                 G.primask = -1;
 665 }
 666
 667 static void kmsg_cleanup(void)
 668 {
 669         if (ENABLE_FEATURE_CLEAN_UP)
 670                 close(G.kmsgfd);
 671 }
 672
 673 /* Write message to /dev/kmsg */
 674 static void log_to_kmsg(int pri, const char *msg)
 675 {
 676         /*
 677          * kernel < 3.5 expects single char printk KERN_* priority prefix,
 678          * from 3.5 onwards the full syslog facility/priority format is supported
 679          */
 680         pri &= G.primask;
 681
 682         full_write(G.kmsgfd, G.printbuf, sprintf(G.printbuf, "<%d>%s\n", pri, msg));
 683 }
 684 #else
 685 static void kmsg_init(void) {}
 686 static void kmsg_cleanup(void) {}
 687 static void log_to_kmsg(int pri UNUSED_PARAM, const char *msg UNUSED_PARAM) {}
 688 #endif /* FEATURE_KMSG_SYSLOG */
 689
 690 /* Print a message to the log file. */
 691 static void log_locally(time_t now, char *msg, logFile_t *log_file)
 692 {
 693 #ifdef SYSLOGD_WRLOCK
 694         struct flock fl;
 695 #endif
 696         int len = strlen(msg);
 697
 698         /* fd can't be 0 (we connect fd 0 to /dev/log socket) */
 699         /* fd is 1 if "-O -" is in use */
 700         if (log_file->fd > 1) {
 701                 /* Reopen log files every second. This allows admin
 702                  * to delete the files and not worry about restarting us.
 703                  * This costs almost nothing since it happens
 704                  * _at most_ once a second for each file, and happens
 705                  * only when each file is actually written.
 706                  */
 707                 if (!now)
 708                         now = time(NULL);
 709                 if (log_file->last_log_time != now) {
 710                         log_file->last_log_time = now;
 711                         close(log_file->fd);
 712                         goto reopen;
 713                 }
 714         }
 715         else if (log_file->fd == 1) {
 716                 /* We are logging to stdout: do nothing */
 717         }
 718         else {
 719                 if (LONE_DASH(log_file->path)) {
 720                         log_file->fd = 1;
 721                         /* log_file->isRegular = 0; - already is */
 722                 } else {
 723  reopen:
 724                         log_file->fd = open(log_file->path, O_WRONLY | O_CREAT
 725                                         | O_NOCTTY | O_APPEND | O_NONBLOCK,
 726                                         0666);
 727                         if (log_file->fd < 0) {
 728                                 /* cannot open logfile? - print to /dev/console then */
 729                                 int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
 730                                 if (fd < 0)
 731                                         fd = 2; /* then stderr, dammit */
 732                                 full_write(fd, msg, len);
 733                                 if (fd != 2)
 734                                         close(fd);
 735                                 return;
 736                         }
 737 #if ENABLE_FEATURE_ROTATE_LOGFILE
 738                         {
 739                                 struct stat statf;
 740                                 log_file->isRegular = (fstat(log_file->fd, &statf) == 0 && S_ISREG(statf.st_mode));
 741                                 /* bug (mostly harmless): can wrap around if file > 4gb */
 742                                 log_file->size = statf.st_size;
 743                         }
 744 #endif
 745                 }
 746         }
 747
 748 #ifdef SYSLOGD_WRLOCK
 749         fl.l_whence = SEEK_SET;
 750         fl.l_start = 0;
 751         fl.l_len = 1;
 752         fl.l_type = F_WRLCK;
 753         fcntl(log_file->fd, F_SETLKW, &fl);
 754 #endif
 755
 756 #if ENABLE_FEATURE_ROTATE_LOGFILE
 757         if (G.logFileSize && log_file->isRegular && log_file->size > G.logFileSize) {
 758                 if (G.logFileRotate) { /* always 0..99 */
 759                         int i = strlen(log_file->path) + 3 + 1;
 760                         char oldFile[i];
 761                         char newFile[i];
 762                         i = G.logFileRotate - 1;
 763                         /* rename: f.8 -> f.9; f.7 -> f.8; ... */
 764                         while (1) {
 765                                 sprintf(newFile, "%s.%d", log_file->path, i);
 766                                 if (i == 0) break;
 767                                 sprintf(oldFile, "%s.%d", log_file->path, --i);
 768                                 /* ignore errors - file might be missing */
 769                                 rename(oldFile, newFile);
 770                         }
 771                         /* newFile == "f.0" now */
 772                         rename(log_file->path, newFile);
 773                 }
 774
 775                 /* We may or may not have just renamed the file away;
 776                  * if we didn't rename because we aren't keeping any backlog,
 777                  * then it's time to clobber the file. If we did rename it...,
 778                  * incredibly, if F and F.0 are hardlinks, POSIX _demands_
 779                  * that rename returns 0 but does not remove F!!!
 780                  * (hardlinked F/F.0 pair was observed after
 781                  * power failure during rename()).
 782                  * So ensure old file is gone in any case:
 783                  */
 784                 unlink(log_file->path);
 785 #ifdef SYSLOGD_WRLOCK
 786                 fl.l_type = F_UNLCK;
 787                 fcntl(log_file->fd, F_SETLKW, &fl);
 788 #endif
 789                 close(log_file->fd);
 790                 goto reopen;
 791         }
 792 /* TODO: what to do on write errors ("disk full")? */
 793         len = full_write(log_file->fd, msg, len);
 794         if (len > 0)
 795                 log_file->size += len;
 796 #else
 797         full_write(log_file->fd, msg, len);
 798 #endif
 799
 800 #ifdef SYSLOGD_WRLOCK
 801         fl.l_type = F_UNLCK;
 802         fcntl(log_file->fd, F_SETLKW, &fl);
 803 #endif
 804 }
 805
 806 static void parse_fac_prio_20(int pri, char *res20)
 807 {
 808         const CODE *c_pri, *c_fac;
 809
 810         c_fac = find_by_val(LOG_FAC(pri) << 3, bb_facilitynames);
 811         if (c_fac) {
 812                 c_pri = find_by_val(LOG_PRI(pri), bb_prioritynames);
 813                 if (c_pri) {
 814                         snprintf(res20, 20, "%s.%s", c_fac->c_name, c_pri->c_name);
 815                         return;
 816                 }
 817         }
 818         snprintf(res20, 20, "<%d>", pri);
 819 }
 820
 821 /* len parameter is used only for "is there a timestamp?" check.
 822  * NB: some callers cheat and supply len==0 when they know
 823  * that there is no timestamp, short-circuiting the test. */
 824 static void timestamp_and_log(int pri, char *msg, int len)
 825 {
 826         char *timestamp = NULL;
 827         time_t now;
 828
 829         /* Jan 18 00:11:22 msg... */
 830         /* 01234567890123456 */
 831         if (len >= 16 && msg[3] == ' ' && msg[6] == ' '
 832          && msg[9] == ':' && msg[12] == ':' && msg[15] == ' '
 833         ) {
 834                 if (!(option_mask32 & OPT_timestamp)) {
 835                         /* use message timestamp */
 836                         timestamp = msg;
 837                         now = 0;
 838                 }
 839                 msg += 16;
 840         }
 841
 842 #if ENABLE_FEATURE_SYSLOGD_PRECISE_TIMESTAMPS
 843         if (!timestamp) {
 844                 struct timeval tv;
 845                 xgettimeofday(&tv);
 846                 now = tv.tv_sec;
 847                 timestamp = ctime(&now) + 4; /* skip day of week */
 848                 /* overwrite year by milliseconds, zero terminate */
 849                 sprintf(timestamp + 15, ".%03u", (unsigned)tv.tv_usec / 1000u);
 850         } else {
 851                 timestamp[15] = '\0';
 852         }
 853 #else
 854         if (!timestamp) {
 855                 time(&now);
 856                 timestamp = ctime(&now) + 4; /* skip day of week */
 857         }
 858         timestamp[15] = '\0';
 859 #endif
 860
 861         if (option_mask32 & OPT_kmsg) {
 862                 log_to_kmsg(pri, msg);
 863                 return;
 864         }
 865
 866         if (option_mask32 & OPT_small)
 867                 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
 868         else {
 869                 char res[20];
 870                 parse_fac_prio_20(pri, res);
 871                 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
 872         }
 873
 874         /* Log message locally (to file or shared mem) */
 875 #if ENABLE_FEATURE_SYSLOGD_CFG
 876         {
 877                 bool match = 0;
 878                 logRule_t *rule;
 879                 uint8_t facility = LOG_FAC(pri);
 880                 uint8_t prio_bit = 1 << LOG_PRI(pri);
 881
 882                 for (rule = G.log_rules; rule; rule = rule->next) {
 883                         if (rule->enabled_facility_priomap[facility] & prio_bit) {
 884                                 log_locally(now, G.printbuf, rule->file);
 885                                 match = 1;
 886                         }
 887                 }
 888                 if (match)
 889                         return;
 890         }
 891 #endif
 892         if (LOG_PRI(pri) < G.logLevel) {
 893 #if ENABLE_FEATURE_IPC_SYSLOG
 894                 if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 895                         log_to_shmem(G.printbuf);
 896                         return;
 897                 }
 898 #endif
 899                 log_locally(now, G.printbuf, &G.logFile);
 900         }
 901 }
 902
 903 static void timestamp_and_log_internal(const char *msg)
 904 {
 905         /* -L, or no -R */
 906         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
 907                 return;
 908         timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
 909 }
 910
 911 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
 912  * embedded NULs. Split messages on each of these NULs, parse prio,
 913  * escape control chars and log each locally. */
 914 static void split_escape_and_log(char *tmpbuf, int len)
 915 {
 916         char *p = tmpbuf;
 917
 918         tmpbuf += len;
 919         while (p < tmpbuf) {
 920                 char c;
 921                 char *q = G.parsebuf;
 922                 int pri = (LOG_USER | LOG_NOTICE);
 923
 924                 if (*p == '<') {
 925                         /* Parse the magic priority number */
 926                         pri = bb_strtou(p + 1, &p, 10);
 927                         if (*p == '>')
 928                                 p++;
 929                         if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 930                                 pri = (LOG_USER | LOG_NOTICE);
 931                 }
 932
 933                 while ((c = *p++)) {
 934                         if (c == '\n')
 935                                 c = ' ';
 936                         if (!(c & ~0x1f) && c != '\t') {
 937                                 *q++ = '^';
 938                                 c += '@'; /* ^@, ^A, ^B... */
 939                         }
 940                         *q++ = c;
 941                 }
 942                 *q = '\0';
 943
 944                 /* Now log it */
 945                 timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
 946         }
 947 }
 948
 949 #ifdef SYSLOGD_MARK
 950 static void do_mark(int sig)
 951 {
 952         if (G.markInterval) {
 953                 timestamp_and_log_internal("-- MARK --");
 954                 alarm(G.markInterval);
 955         }
 956 }
 957 #endif
 958
 959 static int create_socket(void)
 960 {
 961         struct sockaddr_un sunx;
 962         int sock_fd;
 963         char *dev_log_name;
 964
 965         memset(&sunx, 0, sizeof(sunx));
 966         sunx.sun_family = AF_UNIX;
 967
 968         /* Unlink old /dev/log or object it points to. */
 969         /* (if it exists, bind will fail) */
 970         strcpy(sunx.sun_path, _PATH_LOG);
 971         dev_log_name = xmalloc_follow_symlinks(_PATH_LOG);
 972         if (dev_log_name) {
 973                 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
 974                 free(dev_log_name);
 975         }
 976         unlink(sunx.sun_path);
 977
 978         sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
 979         xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
 980         chmod(_PATH_LOG, 0666);
 981
 982         return sock_fd;
 983 }
 984
 985 #if ENABLE_FEATURE_REMOTE_LOG
 986 static int try_to_resolve_remote(remoteHost_t *rh)
 987 {
 988         if (!rh->remoteAddr) {
 989                 unsigned now = monotonic_sec();
 990
 991                 /* Don't resolve name too often - DNS timeouts can be big */
 992                 if ((now - rh->last_dns_resolve) < DNS_WAIT_SEC)
 993                         return -1;
 994                 rh->last_dns_resolve = now;
 995                 rh->remoteAddr = host2sockaddr(rh->remoteHostname, 514);
 996                 if (!rh->remoteAddr)
 997                         return -1;
 998         }
 999         return xsocket(rh->remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
1000 }
1001 #endif
1002
1003 /* By doing init in a separate function we decrease stack usage
1004  * in main loop.
1005  */
1006 static int NOINLINE syslogd_init(char **argv)
1007 {
1008         int opts;
1009         int fd;
1010         char OPTION_DECL;
1011 #if ENABLE_FEATURE_REMOTE_LOG
1012         llist_t *remoteAddrList = NULL;
1013 #endif
1014
1015         /* No non-option params */
1016         opts = getopt32(argv, "^"OPTION_STR"\0""=0", OPTION_PARAM);
1017 #if ENABLE_FEATURE_REMOTE_LOG
1018         while (remoteAddrList) {
1019                 remoteHost_t *rh = xzalloc(sizeof(*rh));
1020                 rh->remoteHostname = llist_pop(&remoteAddrList);
1021                 rh->remoteFD = -1;
1022                 rh->last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
1023                 llist_add_to(&G.remoteHosts, rh);
1024         }
1025 #endif
1026
1027 #ifdef SYSLOGD_MARK
1028         if (opts & OPT_mark) // -m
1029                 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
1030 #endif
1031         //if (opts & OPT_nofork) // -n
1032         //if (opts & OPT_outfile) // -O
1033         if (opts & OPT_loglevel) // -l
1034                 G.logLevel = xatou_range(opt_l, 1, 8);
1035         //if (opts & OPT_small) // -S
1036 #if ENABLE_FEATURE_ROTATE_LOGFILE
1037         if (opts & OPT_filesize) // -s
1038                 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
1039         if (opts & OPT_rotatecnt) // -b
1040                 G.logFileRotate = xatou_range(opt_b, 0, 99);
1041 #endif
1042 #if ENABLE_FEATURE_IPC_SYSLOG
1043         if (opt_C) // -Cn
1044                 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
1045 #endif
1046         /* If they have not specified remote logging, then log locally */
1047         if (ENABLE_FEATURE_REMOTE_LOG && !(opts & OPT_remotelog)) // -R
1048                 option_mask32 |= OPT_locallog;
1049 #if ENABLE_FEATURE_SYSLOGD_CFG
1050         parse_syslogdcfg(opt_f);
1051 #endif
1052
1053         /* Store away localhost's name before the fork */
1054         G.hostname = safe_gethostname();
1055         *strchrnul(G.hostname, '.') = '\0';
1056
1057         fd = create_socket();
1058
1059         if (opts & OPT_circularlog)
1060                 ipcsyslog_init();
1061
1062         if (opts & OPT_kmsg)
1063                 kmsg_init();
1064
1065         if (!(opts & OPT_nofork)) {
1066                 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
1067         }
1068
1069         xmove_fd(fd, STDIN_FILENO);
1070
1071         /* Set up signal handlers (so that they interrupt read()) */
1072         signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo);
1073         signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
1074         //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo);
1075         signal(SIGHUP, SIG_IGN);
1076 #ifdef SYSLOGD_MARK
1077         signal(SIGALRM, do_mark);
1078         alarm(G.markInterval);
1079 #endif
1080         return opts;
1081 }
1082
1083 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1084 int syslogd_main(int argc UNUSED_PARAM, char **argv)
1085 {
1086         int opts;
1087 #if ENABLE_FEATURE_REMOTE_LOG
1088         llist_t *item;
1089 #endif
1090 #if ENABLE_FEATURE_SYSLOGD_DUP
1091         int last_sz = -1;
1092         char *last_buf;
1093         char *recvbuf;
1094 #else
1095 #define recvbuf (G.recvbuf)
1096 #endif
1097
1098         INIT_G();
1099         opts = syslogd_init(argv);
1100
1101         timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
1102         write_pidfile_std_path_and_ext("syslogd");
1103
1104 #if ENABLE_FEATURE_SYSLOGD_DUP
1105         recvbuf = G.recvbuf;
1106 #endif
1107         while (!bb_got_signal) {
1108                 ssize_t sz;
1109
1110 #if ENABLE_FEATURE_SYSLOGD_DUP
1111                 last_buf = recvbuf;
1112                 if (recvbuf == G.recvbuf)
1113                         recvbuf = G.recvbuf + MAX_READ;
1114                 else
1115                         recvbuf = G.recvbuf;
1116 #endif
1117  read_again:
1118                 sz = read(STDIN_FILENO, recvbuf, MAX_READ - 1);
1119                 if (sz < 0) {
1120                         if (!bb_got_signal)
1121                                 bb_perror_msg("read from %s", _PATH_LOG);
1122                         break;
1123                 }
1124
1125                 /* Drop trailing '\n' and NULs (typically there is one NUL) */
1126                 while (1) {
1127                         if (sz == 0)
1128                                 goto read_again;
1129                         /* man 3 syslog says: "A trailing newline is added when needed".
1130                          * However, neither glibc nor uclibc do this:
1131                          * syslog(prio, "test")   sends "test\0" to /dev/log,
1132                          * syslog(prio, "test\n") sends "test\n\0".
1133                          * IOW: newline is passed verbatim!
1134                          * I take it to mean that it's syslogd's job
1135                          * to make those look identical in the log files. */
1136                         if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
1137                                 break;
1138                         sz--;
1139                 }
1140 #if ENABLE_FEATURE_SYSLOGD_DUP
1141                 if ((opts & OPT_dup) && (sz == last_sz))
1142                         if (memcmp(last_buf, recvbuf, sz) == 0)
1143                                 continue;
1144                 last_sz = sz;
1145 #endif
1146 #if ENABLE_FEATURE_REMOTE_LOG
1147                 /* Stock syslogd sends it '\n'-terminated
1148                  * over network, mimic that */
1149                 recvbuf[sz] = '\n';
1150
1151                 /* We are not modifying log messages in any way before send */
1152                 /* Remote site cannot trust _us_ anyway and need to do validation again */
1153                 for (item = G.remoteHosts; item != NULL; item = item->link) {
1154                         remoteHost_t *rh = (remoteHost_t *)item->data;
1155
1156                         if (rh->remoteFD == -1) {
1157                                 rh->remoteFD = try_to_resolve_remote(rh);
1158                                 if (rh->remoteFD == -1)
1159                                         continue;
1160                         }
1161
1162                         /* Send message to remote logger.
1163                          * On some errors, close and set remoteFD to -1
1164                          * so that DNS resolution is retried.
1165                          */
1166                         if (sendto(rh->remoteFD, recvbuf, sz+1,
1167                                         MSG_DONTWAIT | MSG_NOSIGNAL,
1168                                         &(rh->remoteAddr->u.sa), rh->remoteAddr->len) == -1
1169                         ) {
1170                                 switch (errno) {
1171                                 case ECONNRESET:
1172                                 case ENOTCONN: /* paranoia */
1173                                 case EPIPE:
1174                                         close(rh->remoteFD);
1175                                         rh->remoteFD = -1;
1176                                         free(rh->remoteAddr);
1177                                         rh->remoteAddr = NULL;
1178                                 }
1179                         }
1180                 }
1181 #endif
1182                 if (!ENABLE_FEATURE_REMOTE_LOG || (opts & OPT_locallog)) {
1183                         recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
1184                         split_escape_and_log(recvbuf, sz);
1185                 }
1186         } /* while (!bb_got_signal) */
1187
1188         timestamp_and_log_internal("syslogd exiting");
1189         remove_pidfile_std_path_and_ext("syslogd");
1190         ipcsyslog_cleanup();
1191         if (opts & OPT_kmsg)
1192                 kmsg_cleanup();
1193         kill_myself_with_sig(bb_got_signal);
1194 #undef recvbuf
1195 }
1196
1197 /* Clean up. Needed because we are included from syslogd_and_logger.c */
1198 #undef DEBUG
1199 #undef SYSLOGD_MARK
1200 #undef SYSLOGD_WRLOCK
1201 #undef G
1202 #undef GLOBALS
1203 #undef INIT_G
1204 #undef OPTION_STR
1205 #undef OPTION_DECL
1206 #undef OPTION_PARAM