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
  16 //usage:#define syslogd_trivial_usage
  17 //usage:       "[OPTIONS]"
  18 //usage:#define syslogd_full_usage "\n\n"
  19 //usage:       "System logging utility.\n"
  20 //usage:       "This version of syslogd ignores /etc/syslog.conf\n"
  21 //usage:     "\nOptions:"
  22 //usage:     "\n        -n              Run in foreground"
  23 //usage:     "\n        -O FILE         Log to given file (default:/var/log/messages)"
  24 //usage:     "\n        -l N            Set local log level"
  25 //usage:     "\n        -S              Smaller logging output"
  26 //usage:        IF_FEATURE_ROTATE_LOGFILE(
  27 //usage:     "\n        -s SIZE         Max size (KB) before rotate (default:200KB, 0=off)"
  28 //usage:     "\n        -b N            N rotated logs to keep (default:1, max=99, 0=purge)")
  29 //usage:        IF_FEATURE_REMOTE_LOG(
  30 //usage:     "\n        -R HOST[:PORT]  Log to IP or hostname on PORT (default PORT=514/UDP)"
  31 //usage:     "\n        -L              Log locally and via network (default is network only if -R)")
  32 //usage:        IF_FEATURE_SYSLOGD_DUP(
  33 //usage:     "\n        -D              Drop duplicates")
  34 //usage:        IF_FEATURE_IPC_SYSLOG(
  35 //usage:     "\n        -C[size(KiB)]   Log to shared mem buffer (read it using logread)")
  36 //usage:        IF_FEATURE_SYSLOGD_CFG(
  37 //usage:     "\n        -f FILE         Use FILE as config (default is /etc/syslog.conf)")
  38 /* NB: -Csize shouldn't have space (because size is optional) */
  39 /* //usage:  "\n        -m MIN          Minutes between MARK lines (default:20, 0=off)" */
  40 //usage:
  41 //usage:#define syslogd_example_usage
  42 //usage:       "$ syslogd -R masterlog:514\n"
  43 //usage:       "$ syslogd -R 192.168.1.1:601\n"
  44
  45 /*
  46  * Done in syslogd_and_logger.c:
  47 #include "libbb.h"
  48 #define SYSLOG_NAMES
  49 #define SYSLOG_NAMES_CONST
  50 #include <syslog.h>
  51 */
  52
  53 #include <sys/un.h>
  54 #include <sys/uio.h>
  55
  56 #if ENABLE_FEATURE_REMOTE_LOG
  57 #include <netinet/in.h>
  58 #endif
  59
  60 #if ENABLE_FEATURE_IPC_SYSLOG
  61 #include <sys/ipc.h>
  62 #include <sys/sem.h>
  63 #include <sys/shm.h>
  64 #endif
  65
  66
  67 #define DEBUG 0
  68
  69 /* MARK code is not very useful, is bloat, and broken:
  70  * can deadlock if alarmed to make MARK while writing to IPC buffer
  71  * (semaphores are down but do_mark routine tries to down them again) */
  72 #undef SYSLOGD_MARK
  73
  74 /* Write locking does not seem to be useful either */
  75 #undef SYSLOGD_WRLOCK
  76
  77 enum {
  78         MAX_READ = CONFIG_FEATURE_SYSLOGD_READ_BUFFER_SIZE,
  79         DNS_WAIT_SEC = 2 * 60,
  80 };
  81
  82 /* Semaphore operation structures */
  83 struct shbuf_ds {
  84         int32_t size;   /* size of data - 1 */
  85         int32_t tail;   /* end of message list */
  86         char data[1];   /* data/messages */
  87 };
  88
  89 #if ENABLE_FEATURE_REMOTE_LOG
  90 typedef struct {
  91         int remoteFD;
  92         unsigned last_dns_resolve;
  93         len_and_sockaddr *remoteAddr;
  94         const char *remoteHostname;
  95 } remoteHost_t;
  96 #endif
  97
  98 typedef struct logFile_t {
  99         const char *path;
 100         int fd;
 101 #if ENABLE_FEATURE_ROTATE_LOGFILE
 102         unsigned size;
 103         uint8_t isRegular;
 104 #endif
 105 } logFile_t;
 106
 107 #if ENABLE_FEATURE_SYSLOGD_CFG
 108 typedef struct logRule_t {
 109         uint8_t enabled_facility_priomap[LOG_NFACILITIES];
 110         struct logFile_t *file;
 111         struct logRule_t *next;
 112 } logRule_t;
 113 #endif
 114
 115 /* Allows us to have smaller initializer. Ugly. */
 116 #define GLOBALS \
 117         logFile_t logFile;                      \
 118         /* interval between marks in seconds */ \
 119         /*int markInterval;*/                   \
 120         /* level of messages to be logged */    \
 121         int logLevel;                           \
 122 IF_FEATURE_ROTATE_LOGFILE( \
 123         /* max size of file before rotation */  \
 124         unsigned logFileSize;                   \
 125         /* number of rotated message files */   \
 126         unsigned logFileRotate;                 \
 127 ) \
 128 IF_FEATURE_IPC_SYSLOG( \
 129         int shmid; /* ipc shared memory id */   \
 130         int s_semid; /* ipc semaphore id */     \
 131         int shm_size;                           \
 132         struct sembuf SMwup[1];                 \
 133         struct sembuf SMwdn[3];                 \
 134 ) \
 135 IF_FEATURE_SYSLOGD_CFG( \
 136         logRule_t *log_rules; \
 137 )
 138
 139 struct init_globals {
 140         GLOBALS
 141 };
 142
 143 struct globals {
 144         GLOBALS
 145
 146 #if ENABLE_FEATURE_REMOTE_LOG
 147         llist_t *remoteHosts;
 148 #endif
 149 #if ENABLE_FEATURE_IPC_SYSLOG
 150         struct shbuf_ds *shbuf;
 151 #endif
 152         time_t last_log_time;
 153         /* localhost's name. We print only first 64 chars */
 154         char *hostname;
 155
 156         /* We recv into recvbuf... */
 157         char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
 158         /* ...then copy to parsebuf, escaping control chars */
 159         /* (can grow x2 max) */
 160         char parsebuf[MAX_READ*2];
 161         /* ...then sprintf into printbuf, adding timestamp (15 chars),
 162          * host (64), fac.prio (20) to the message */
 163         /* (growth by: 15 + 64 + 20 + delims = ~110) */
 164         char printbuf[MAX_READ*2 + 128];
 165 };
 166
 167 static const struct init_globals init_data = {
 168         .logFile = {
 169                 .path = "/var/log/messages",
 170                 .fd = -1,
 171         },
 172 #ifdef SYSLOGD_MARK
 173         .markInterval = 20 * 60,
 174 #endif
 175         .logLevel = 8,
 176 #if ENABLE_FEATURE_ROTATE_LOGFILE
 177         .logFileSize = 200 * 1024,
 178         .logFileRotate = 1,
 179 #endif
 180 #if ENABLE_FEATURE_IPC_SYSLOG
 181         .shmid = -1,
 182         .s_semid = -1,
 183         .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), /* default shm size */
 184         .SMwup = { {1, -1, IPC_NOWAIT} },
 185         .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
 186 #endif
 187 };
 188
 189 #define G (*ptr_to_globals)
 190 #define INIT_G() do { \
 191         SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
 192 } while (0)
 193
 194
 195 /* Options */
 196 enum {
 197         OPTBIT_mark = 0, // -m
 198         OPTBIT_nofork, // -n
 199         OPTBIT_outfile, // -O
 200         OPTBIT_loglevel, // -l
 201         OPTBIT_small, // -S
 202         IF_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,)  // -s
 203         IF_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,)  // -b
 204         IF_FEATURE_REMOTE_LOG(    OPTBIT_remotelog  ,)  // -R
 205         IF_FEATURE_REMOTE_LOG(    OPTBIT_locallog   ,)  // -L
 206         IF_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,)  // -C
 207         IF_FEATURE_SYSLOGD_DUP(   OPTBIT_dup        ,)  // -D
 208         IF_FEATURE_SYSLOGD_CFG(   OPTBIT_cfg        ,)  // -f
 209
 210         OPT_mark        = 1 << OPTBIT_mark    ,
 211         OPT_nofork      = 1 << OPTBIT_nofork  ,
 212         OPT_outfile     = 1 << OPTBIT_outfile ,
 213         OPT_loglevel    = 1 << OPTBIT_loglevel,
 214         OPT_small       = 1 << OPTBIT_small   ,
 215         OPT_filesize    = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
 216         OPT_rotatecnt   = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
 217         OPT_remotelog   = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remotelog  )) + 0,
 218         OPT_locallog    = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_locallog   )) + 0,
 219         OPT_circularlog = IF_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
 220         OPT_dup         = IF_FEATURE_SYSLOGD_DUP(   (1 << OPTBIT_dup        )) + 0,
 221         OPT_cfg         = IF_FEATURE_SYSLOGD_CFG(   (1 << OPTBIT_cfg        )) + 0,
 222 };
 223 #define OPTION_STR "m:nO:l:S" \
 224         IF_FEATURE_ROTATE_LOGFILE("s:" ) \
 225         IF_FEATURE_ROTATE_LOGFILE("b:" ) \
 226         IF_FEATURE_REMOTE_LOG(    "R:" ) \
 227         IF_FEATURE_REMOTE_LOG(    "L"  ) \
 228         IF_FEATURE_IPC_SYSLOG(    "C::") \
 229         IF_FEATURE_SYSLOGD_DUP(   "D"  ) \
 230         IF_FEATURE_SYSLOGD_CFG(   "f:"  )
 231 #define OPTION_DECL *opt_m, *opt_l \
 232         IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \
 233         IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \
 234         IF_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL) \
 235         IF_FEATURE_SYSLOGD_CFG(   ,*opt_f = NULL)
 236 #define OPTION_PARAM &opt_m, &(G.logFile.path), &opt_l \
 237         IF_FEATURE_ROTATE_LOGFILE(,&opt_s) \
 238         IF_FEATURE_ROTATE_LOGFILE(,&opt_b) \
 239         IF_FEATURE_REMOTE_LOG(    ,&remoteAddrList) \
 240         IF_FEATURE_IPC_SYSLOG(    ,&opt_C) \
 241         IF_FEATURE_SYSLOGD_CFG(   ,&opt_f)
 242
 243
 244 #if ENABLE_FEATURE_SYSLOGD_CFG
 245 static const CODE* find_by_name(char *name, const CODE* c_set)
 246 {
 247         for (; c_set->c_name; c_set++) {
 248                 if (strcmp(name, c_set->c_name) == 0)
 249                         return c_set;
 250         }
 251         return NULL;
 252 }
 253 #endif
 254 static const CODE* find_by_val(int val, const CODE* c_set)
 255 {
 256         for (; c_set->c_name; c_set++) {
 257                 if (c_set->c_val == val)
 258                         return c_set;
 259         }
 260         return NULL;
 261 }
 262
 263 #if ENABLE_FEATURE_SYSLOGD_CFG
 264 static void parse_syslogdcfg(const char *file)
 265 {
 266         char *t;
 267         logRule_t **pp_rule;
 268         /* tok[0] set of selectors */
 269         /* tok[1] file name */
 270         /* tok[2] has to be NULL */
 271         char *tok[3];
 272         parser_t *parser;
 273
 274         parser = config_open2(file ? file : "/etc/syslog.conf",
 275                                 file ? xfopen_for_read : fopen_or_warn_stdin);
 276         if (!parser)
 277                 /* didn't find default /etc/syslog.conf */
 278                 /* proceed as if we built busybox without config support */
 279                 return;
 280
 281         /* use ptr to ptr to avoid checking whether head was initialized */
 282         pp_rule = &G.log_rules;
 283         /* iterate through lines of config, skipping comments */
 284         while (config_read(parser, tok, 3, 2, "# \t", PARSE_NORMAL | PARSE_MIN_DIE)) {
 285                 char *cur_selector;
 286                 logRule_t *cur_rule;
 287
 288                 /* unexpected trailing token? */
 289                 if (tok[2])
 290                         goto cfgerr;
 291
 292                 cur_rule = *pp_rule = xzalloc(sizeof(*cur_rule));
 293
 294                 cur_selector = tok[0];
 295                 /* iterate through selectors: "kern.info;kern.!err;..." */
 296                 do {
 297                         const CODE *code;
 298                         char *next_selector;
 299                         uint8_t negated_prio; /* "kern.!err" */
 300                         uint8_t single_prio;  /* "kern.=err" */
 301                         uint32_t facmap; /* bitmap of enabled facilities */
 302                         uint8_t primap;  /* bitmap of enabled priorities */
 303                         unsigned i;
 304
 305                         next_selector = strchr(cur_selector, ';');
 306                         if (next_selector)
 307                                 *next_selector++ = '\0';
 308
 309                         t = strchr(cur_selector, '.');
 310                         if (!t)
 311                                 goto cfgerr;
 312                         *t++ = '\0'; /* separate facility from priority */
 313
 314                         negated_prio = 0;
 315                         single_prio = 0;
 316                         if (*t == '!') {
 317                                 negated_prio = 1;
 318                                 ++t;
 319                         }
 320                         if (*t == '=') {
 321                                 single_prio = 1;
 322                                 ++t;
 323                         }
 324
 325                         /* parse priority */
 326                         if (*t == '*')
 327                                 primap = 0xff; /* all 8 log levels enabled */
 328                         else {
 329                                 uint8_t priority;
 330                                 code = find_by_name(t, prioritynames);
 331                                 if (!code)
 332                                         goto cfgerr;
 333                                 primap = 0;
 334                                 priority = code->c_val;
 335                                 if (priority == INTERNAL_NOPRI) {
 336                                         /* ensure we take "enabled_facility_priomap[fac] &= 0" branch below */
 337                                         negated_prio = 1;
 338                                 } else {
 339                                         priority = 1 << priority;
 340                                         do {
 341                                                 primap |= priority;
 342                                                 if (single_prio)
 343                                                         break;
 344                                                 priority >>= 1;
 345                                         } while (priority);
 346                                         if (negated_prio)
 347                                                 primap = ~primap;
 348                                 }
 349                         }
 350
 351                         /* parse facility */
 352                         if (*cur_selector == '*')
 353                                 facmap = (1<<LOG_NFACILITIES) - 1;
 354                         else {
 355                                 char *next_facility;
 356                                 facmap = 0;
 357                                 t = cur_selector;
 358                                 /* iterate through facilities: "kern,daemon.<priospec>" */
 359                                 do {
 360                                         next_facility = strchr(t, ',');
 361                                         if (next_facility)
 362                                                 *next_facility++ = '\0';
 363                                         code = find_by_name(t, facilitynames);
 364                                         if (!code)
 365                                                 goto cfgerr;
 366                                         /* "mark" is not a real facility, skip it */
 367                                         if (code->c_val != INTERNAL_MARK)
 368                                                 facmap |= 1<<(LOG_FAC(code->c_val));
 369                                         t = next_facility;
 370                                 } while (t);
 371                         }
 372
 373                         /* merge result with previous selectors */
 374                         for (i = 0; i < LOG_NFACILITIES; ++i) {
 375                                 if (!(facmap & (1<<i)))
 376                                         continue;
 377                                 if (negated_prio)
 378                                         cur_rule->enabled_facility_priomap[i] &= primap;
 379                                 else
 380                                         cur_rule->enabled_facility_priomap[i] |= primap;
 381                         }
 382
 383                         cur_selector = next_selector;
 384                 } while (cur_selector);
 385
 386                 /* check whether current file name was mentioned in previous rules or
 387                  * as global logfile (G.logFile).
 388                  */
 389                 if (strcmp(G.logFile.path, tok[1]) == 0) {
 390                         cur_rule->file = &G.logFile;
 391                         goto found;
 392                 }
 393                 /* temporarily use cur_rule as iterator, but *pp_rule still points
 394                  * to currently processing rule entry.
 395                  * NOTE: *pp_rule points to the current (and last in the list) rule.
 396                  */
 397                 for (cur_rule = G.log_rules; cur_rule != *pp_rule; cur_rule = cur_rule->next) {
 398                         if (strcmp(cur_rule->file->path, tok[1]) == 0) {
 399                                 /* found - reuse the same file structure */
 400                                 (*pp_rule)->file = cur_rule->file;
 401                                 cur_rule = *pp_rule;
 402                                 goto found;
 403                         }
 404                 }
 405                 cur_rule->file = xzalloc(sizeof(*cur_rule->file));
 406                 cur_rule->file->fd = -1;
 407                 cur_rule->file->path = xstrdup(tok[1]);
 408  found:
 409                 pp_rule = &cur_rule->next;
 410         }
 411         config_close(parser);
 412         return;
 413
 414  cfgerr:
 415         bb_error_msg_and_die("error in '%s' at line %d", file, parser->lineno);
 416 }
 417 #endif
 418
 419 /* circular buffer variables/structures */
 420 #if ENABLE_FEATURE_IPC_SYSLOG
 421
 422 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
 423 #error Sorry, you must set the syslogd buffer size to at least 4KB.
 424 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 425 #endif
 426
 427 /* our shared key (syslogd.c and logread.c must be in sync) */
 428 enum { KEY_ID = 0x414e4547 }; /* "GENA" */
 429
 430 static void ipcsyslog_cleanup(void)
 431 {
 432         if (G.shmid != -1) {
 433                 shmdt(G.shbuf);
 434         }
 435         if (G.shmid != -1) {
 436                 shmctl(G.shmid, IPC_RMID, NULL);
 437         }
 438         if (G.s_semid != -1) {
 439                 semctl(G.s_semid, 0, IPC_RMID, 0);
 440         }
 441 }
 442
 443 static void ipcsyslog_init(void)
 444 {
 445         if (DEBUG)
 446                 printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
 447
 448         G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
 449         if (G.shmid == -1) {
 450                 bb_perror_msg_and_die("shmget");
 451         }
 452
 453         G.shbuf = shmat(G.shmid, NULL, 0);
 454         if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
 455                 bb_perror_msg_and_die("shmat");
 456         }
 457
 458         memset(G.shbuf, 0, G.shm_size);
 459         G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
 460         /*G.shbuf->tail = 0;*/
 461
 462         /* we'll trust the OS to set initial semval to 0 (let's hope) */
 463         G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
 464         if (G.s_semid == -1) {
 465                 if (errno == EEXIST) {
 466                         G.s_semid = semget(KEY_ID, 2, 0);
 467                         if (G.s_semid != -1)
 468                                 return;
 469                 }
 470                 bb_perror_msg_and_die("semget");
 471         }
 472 }
 473
 474 /* Write message to shared mem buffer */
 475 static void log_to_shmem(const char *msg)
 476 {
 477         int old_tail, new_tail;
 478         int len;
 479
 480         if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 481                 bb_perror_msg_and_die("SMwdn");
 482         }
 483
 484         /* Circular Buffer Algorithm:
 485          * --------------------------
 486          * tail == position where to store next syslog message.
 487          * tail's max value is (shbuf->size - 1)
 488          * Last byte of buffer is never used and remains NUL.
 489          */
 490         len = strlen(msg) + 1; /* length with NUL included */
 491  again:
 492         old_tail = G.shbuf->tail;
 493         new_tail = old_tail + len;
 494         if (new_tail < G.shbuf->size) {
 495                 /* store message, set new tail */
 496                 memcpy(G.shbuf->data + old_tail, msg, len);
 497                 G.shbuf->tail = new_tail;
 498         } else {
 499                 /* k == available buffer space ahead of old tail */
 500                 int k = G.shbuf->size - old_tail;
 501                 /* copy what fits to the end of buffer, and repeat */
 502                 memcpy(G.shbuf->data + old_tail, msg, k);
 503                 msg += k;
 504                 len -= k;
 505                 G.shbuf->tail = 0;
 506                 goto again;
 507         }
 508         if (semop(G.s_semid, G.SMwup, 1) == -1) {
 509                 bb_perror_msg_and_die("SMwup");
 510         }
 511         if (DEBUG)
 512                 printf("tail:%d\n", G.shbuf->tail);
 513 }
 514 #else
 515 void ipcsyslog_cleanup(void);
 516 void ipcsyslog_init(void);
 517 void log_to_shmem(const char *msg);
 518 #endif /* FEATURE_IPC_SYSLOG */
 519
 520 /* Print a message to the log file. */
 521 static void log_locally(time_t now, char *msg, logFile_t *log_file)
 522 {
 523 #ifdef SYSLOGD_WRLOCK
 524         struct flock fl;
 525 #endif
 526         int len = strlen(msg);
 527
 528         if (log_file->fd >= 0) {
 529                 /* Reopen log file every second. This allows admin
 530                  * to delete the file and not worry about restarting us.
 531                  * This costs almost nothing since it happens
 532                  * _at most_ once a second.
 533                  */
 534                 if (!now)
 535                         now = time(NULL);
 536                 if (G.last_log_time != now) {
 537                         G.last_log_time = now;
 538                         close(log_file->fd);
 539                         goto reopen;
 540                 }
 541         } else {
 542  reopen:
 543                 log_file->fd = open(log_file->path, O_WRONLY | O_CREAT
 544                                         | O_NOCTTY | O_APPEND | O_NONBLOCK,
 545                                         0666);
 546                 if (log_file->fd < 0) {
 547                         /* cannot open logfile? - print to /dev/console then */
 548                         int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
 549                         if (fd < 0)
 550                                 fd = 2; /* then stderr, dammit */
 551                         full_write(fd, msg, len);
 552                         if (fd != 2)
 553                                 close(fd);
 554                         return;
 555                 }
 556 #if ENABLE_FEATURE_ROTATE_LOGFILE
 557                 {
 558                         struct stat statf;
 559                         log_file->isRegular = (fstat(log_file->fd, &statf) == 0 && S_ISREG(statf.st_mode));
 560                         /* bug (mostly harmless): can wrap around if file > 4gb */
 561                         log_file->size = statf.st_size;
 562                 }
 563 #endif
 564         }
 565
 566 #ifdef SYSLOGD_WRLOCK
 567         fl.l_whence = SEEK_SET;
 568         fl.l_start = 0;
 569         fl.l_len = 1;
 570         fl.l_type = F_WRLCK;
 571         fcntl(log_file->fd, F_SETLKW, &fl);
 572 #endif
 573
 574 #if ENABLE_FEATURE_ROTATE_LOGFILE
 575         if (G.logFileSize && log_file->isRegular && log_file->size > G.logFileSize) {
 576                 if (G.logFileRotate) { /* always 0..99 */
 577                         int i = strlen(log_file->path) + 3 + 1;
 578                         char oldFile[i];
 579                         char newFile[i];
 580                         i = G.logFileRotate - 1;
 581                         /* rename: f.8 -> f.9; f.7 -> f.8; ... */
 582                         while (1) {
 583                                 sprintf(newFile, "%s.%d", log_file->path, i);
 584                                 if (i == 0) break;
 585                                 sprintf(oldFile, "%s.%d", log_file->path, --i);
 586                                 /* ignore errors - file might be missing */
 587                                 rename(oldFile, newFile);
 588                         }
 589                         /* newFile == "f.0" now */
 590                         rename(log_file->path, newFile);
 591 #ifdef SYSLOGD_WRLOCK
 592                         fl.l_type = F_UNLCK;
 593                         fcntl(log_file->fd, F_SETLKW, &fl);
 594 #endif
 595                         close(log_file->fd);
 596                         goto reopen;
 597                 }
 598                 ftruncate(log_file->fd, 0);
 599         }
 600         log_file->size +=
 601 #endif
 602                         full_write(log_file->fd, msg, len);
 603 #ifdef SYSLOGD_WRLOCK
 604         fl.l_type = F_UNLCK;
 605         fcntl(log_file->fd, F_SETLKW, &fl);
 606 #endif
 607 }
 608
 609 static void parse_fac_prio_20(int pri, char *res20)
 610 {
 611         const CODE *c_pri, *c_fac;
 612
 613         c_fac = find_by_val(LOG_FAC(pri) << 3, facilitynames);
 614         if (c_fac) {
 615                 c_pri = find_by_val(LOG_PRI(pri), prioritynames);
 616                 if (c_pri) {
 617                         snprintf(res20, 20, "%s.%s", c_fac->c_name, c_pri->c_name);
 618                         return;
 619                 }
 620         }
 621         snprintf(res20, 20, "<%d>", pri);
 622 }
 623
 624 /* len parameter is used only for "is there a timestamp?" check.
 625  * NB: some callers cheat and supply len==0 when they know
 626  * that there is no timestamp, short-circuiting the test. */
 627 static void timestamp_and_log(int pri, char *msg, int len)
 628 {
 629         char *timestamp;
 630         time_t now;
 631
 632         /* Jan 18 00:11:22 msg... */
 633         /* 01234567890123456 */
 634         if (len < 16 || msg[3] != ' ' || msg[6] != ' '
 635          || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
 636         ) {
 637                 time(&now);
 638                 timestamp = ctime(&now) + 4; /* skip day of week */
 639         } else {
 640                 now = 0;
 641                 timestamp = msg;
 642                 msg += 16;
 643         }
 644         timestamp[15] = '\0';
 645
 646         if (option_mask32 & OPT_small)
 647                 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
 648         else {
 649                 char res[20];
 650                 parse_fac_prio_20(pri, res);
 651                 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
 652         }
 653
 654         /* Log message locally (to file or shared mem) */
 655 #if ENABLE_FEATURE_SYSLOGD_CFG
 656         {
 657                 bool match = 0;
 658                 logRule_t *rule;
 659                 uint8_t facility = LOG_FAC(pri);
 660                 uint8_t prio_bit = 1 << LOG_PRI(pri);
 661
 662                 for (rule = G.log_rules; rule; rule = rule->next) {
 663                         if (rule->enabled_facility_priomap[facility] & prio_bit) {
 664                                 log_locally(now, G.printbuf, rule->file);
 665                                 match = 1;
 666                         }
 667                 }
 668                 if (match)
 669                         return;
 670         }
 671 #endif
 672         if (LOG_PRI(pri) < G.logLevel) {
 673 #if ENABLE_FEATURE_IPC_SYSLOG
 674                 if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 675                         log_to_shmem(msg);
 676                         return;
 677                 }
 678 #endif
 679                 log_locally(now, G.printbuf, &G.logFile);
 680         }
 681 }
 682
 683 static void timestamp_and_log_internal(const char *msg)
 684 {
 685         /* -L, or no -R */
 686         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
 687                 return;
 688         timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
 689 }
 690
 691 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
 692  * embedded NULs. Split messages on each of these NULs, parse prio,
 693  * escape control chars and log each locally. */
 694 static void split_escape_and_log(char *tmpbuf, int len)
 695 {
 696         char *p = tmpbuf;
 697
 698         tmpbuf += len;
 699         while (p < tmpbuf) {
 700                 char c;
 701                 char *q = G.parsebuf;
 702                 int pri = (LOG_USER | LOG_NOTICE);
 703
 704                 if (*p == '<') {
 705                         /* Parse the magic priority number */
 706                         pri = bb_strtou(p + 1, &p, 10);
 707                         if (*p == '>')
 708                                 p++;
 709                         if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 710                                 pri = (LOG_USER | LOG_NOTICE);
 711                 }
 712
 713                 while ((c = *p++)) {
 714                         if (c == '\n')
 715                                 c = ' ';
 716                         if (!(c & ~0x1f) && c != '\t') {
 717                                 *q++ = '^';
 718                                 c += '@'; /* ^@, ^A, ^B... */
 719                         }
 720                         *q++ = c;
 721                 }
 722                 *q = '\0';
 723
 724                 /* Now log it */
 725                 timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
 726         }
 727 }
 728
 729 #ifdef SYSLOGD_MARK
 730 static void do_mark(int sig)
 731 {
 732         if (G.markInterval) {
 733                 timestamp_and_log_internal("-- MARK --");
 734                 alarm(G.markInterval);
 735         }
 736 }
 737 #endif
 738
 739 /* Don't inline: prevent struct sockaddr_un to take up space on stack
 740  * permanently */
 741 static NOINLINE int create_socket(void)
 742 {
 743         struct sockaddr_un sunx;
 744         int sock_fd;
 745         char *dev_log_name;
 746
 747 #if ENABLE_FEATURE_SYSTEMD
 748         if (sd_listen_fds() == 1)
 749                 return SD_LISTEN_FDS_START;
 750 #endif
 751
 752         memset(&sunx, 0, sizeof(sunx));
 753         sunx.sun_family = AF_UNIX;
 754
 755         /* Unlink old /dev/log or object it points to. */
 756         /* (if it exists, bind will fail) */
 757         strcpy(sunx.sun_path, "/dev/log");
 758         dev_log_name = xmalloc_follow_symlinks("/dev/log");
 759         if (dev_log_name) {
 760                 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
 761                 free(dev_log_name);
 762         }
 763         unlink(sunx.sun_path);
 764
 765         sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
 766         xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
 767         chmod("/dev/log", 0666);
 768
 769         return sock_fd;
 770 }
 771
 772 #if ENABLE_FEATURE_REMOTE_LOG
 773 static int try_to_resolve_remote(remoteHost_t *rh)
 774 {
 775         if (!rh->remoteAddr) {
 776                 unsigned now = monotonic_sec();
 777
 778                 /* Don't resolve name too often - DNS timeouts can be big */
 779                 if ((now - rh->last_dns_resolve) < DNS_WAIT_SEC)
 780                         return -1;
 781                 rh->last_dns_resolve = now;
 782                 rh->remoteAddr = host2sockaddr(rh->remoteHostname, 514);
 783                 if (!rh->remoteAddr)
 784                         return -1;
 785         }
 786         return xsocket(rh->remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
 787 }
 788 #endif
 789
 790 static void do_syslogd(void) NORETURN;
 791 static void do_syslogd(void)
 792 {
 793         int sock_fd;
 794 #if ENABLE_FEATURE_REMOTE_LOG
 795         llist_t *item;
 796 #endif
 797 #if ENABLE_FEATURE_SYSLOGD_DUP
 798         int last_sz = -1;
 799         char *last_buf;
 800         char *recvbuf = G.recvbuf;
 801 #else
 802 #define recvbuf (G.recvbuf)
 803 #endif
 804
 805         /* Set up signal handlers (so that they interrupt read()) */
 806         signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo);
 807         signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
 808         //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo);
 809         signal(SIGHUP, SIG_IGN);
 810 #ifdef SYSLOGD_MARK
 811         signal(SIGALRM, do_mark);
 812         alarm(G.markInterval);
 813 #endif
 814         sock_fd = create_socket();
 815
 816         if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
 817                 ipcsyslog_init();
 818         }
 819
 820         timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
 821
 822         while (!bb_got_signal) {
 823                 ssize_t sz;
 824
 825 #if ENABLE_FEATURE_SYSLOGD_DUP
 826                 last_buf = recvbuf;
 827                 if (recvbuf == G.recvbuf)
 828                         recvbuf = G.recvbuf + MAX_READ;
 829                 else
 830                         recvbuf = G.recvbuf;
 831 #endif
 832  read_again:
 833                 sz = read(sock_fd, recvbuf, MAX_READ - 1);
 834                 if (sz < 0) {
 835                         if (!bb_got_signal)
 836                                 bb_perror_msg("read from /dev/log");
 837                         break;
 838                 }
 839
 840                 /* Drop trailing '\n' and NULs (typically there is one NUL) */
 841                 while (1) {
 842                         if (sz == 0)
 843                                 goto read_again;
 844                         /* man 3 syslog says: "A trailing newline is added when needed".
 845                          * However, neither glibc nor uclibc do this:
 846                          * syslog(prio, "test")   sends "test\0" to /dev/log,
 847                          * syslog(prio, "test\n") sends "test\n\0".
 848                          * IOW: newline is passed verbatim!
 849                          * I take it to mean that it's syslogd's job
 850                          * to make those look identical in the log files. */
 851                         if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
 852                                 break;
 853                         sz--;
 854                 }
 855 #if ENABLE_FEATURE_SYSLOGD_DUP
 856                 if ((option_mask32 & OPT_dup) && (sz == last_sz))
 857                         if (memcmp(last_buf, recvbuf, sz) == 0)
 858                                 continue;
 859                 last_sz = sz;
 860 #endif
 861 #if ENABLE_FEATURE_REMOTE_LOG
 862                 /* Stock syslogd sends it '\n'-terminated
 863                  * over network, mimic that */
 864                 recvbuf[sz] = '\n';
 865
 866                 /* We are not modifying log messages in any way before send */
 867                 /* Remote site cannot trust _us_ anyway and need to do validation again */
 868                 for (item = G.remoteHosts; item != NULL; item = item->link) {
 869                         remoteHost_t *rh = (remoteHost_t *)item->data;
 870
 871                         if (rh->remoteFD == -1) {
 872                                 rh->remoteFD = try_to_resolve_remote(rh);
 873                                 if (rh->remoteFD == -1)
 874                                         continue;
 875                         }
 876
 877                         /* Send message to remote logger.
 878                          * On some errors, close and set remoteFD to -1
 879                          * so that DNS resolution is retried.
 880                          */
 881                         if (sendto(rh->remoteFD, recvbuf, sz+1,
 882                                         MSG_DONTWAIT | MSG_NOSIGNAL,
 883                                         &(rh->remoteAddr->u.sa), rh->remoteAddr->len) == -1
 884                         ) {
 885                                 switch (errno) {
 886                                 case ECONNRESET:
 887                                 case ENOTCONN: /* paranoia */
 888                                 case EPIPE:
 889                                         close(rh->remoteFD);
 890                                         rh->remoteFD = -1;
 891                                         free(rh->remoteAddr);
 892                                         rh->remoteAddr = NULL;
 893                                 }
 894                         }
 895                 }
 896 #endif
 897                 if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
 898                         recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
 899                         split_escape_and_log(recvbuf, sz);
 900                 }
 901         } /* while (!bb_got_signal) */
 902
 903         timestamp_and_log_internal("syslogd exiting");
 904         puts("syslogd exiting");
 905         if (ENABLE_FEATURE_IPC_SYSLOG)
 906                 ipcsyslog_cleanup();
 907         kill_myself_with_sig(bb_got_signal);
 908 #undef recvbuf
 909 }
 910
 911 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 912 int syslogd_main(int argc UNUSED_PARAM, char **argv)
 913 {
 914         int opts;
 915         char OPTION_DECL;
 916 #if ENABLE_FEATURE_REMOTE_LOG
 917         llist_t *remoteAddrList = NULL;
 918 #endif
 919
 920         INIT_G();
 921
 922         /* No non-option params, -R can occur multiple times */
 923         opt_complementary = "=0" IF_FEATURE_REMOTE_LOG(":R::");
 924         opts = getopt32(argv, OPTION_STR, OPTION_PARAM);
 925 #if ENABLE_FEATURE_REMOTE_LOG
 926         while (remoteAddrList) {
 927                 remoteHost_t *rh = xzalloc(sizeof(*rh));
 928                 rh->remoteHostname = llist_pop(&remoteAddrList);
 929                 rh->remoteFD = -1;
 930                 rh->last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
 931                 llist_add_to(&G.remoteHosts, rh);
 932         }
 933 #endif
 934
 935 #ifdef SYSLOGD_MARK
 936         if (opts & OPT_mark) // -m
 937                 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
 938 #endif
 939         //if (opts & OPT_nofork) // -n
 940         //if (opts & OPT_outfile) // -O
 941         if (opts & OPT_loglevel) // -l
 942                 G.logLevel = xatou_range(opt_l, 1, 8);
 943         //if (opts & OPT_small) // -S
 944 #if ENABLE_FEATURE_ROTATE_LOGFILE
 945         if (opts & OPT_filesize) // -s
 946                 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
 947         if (opts & OPT_rotatecnt) // -b
 948                 G.logFileRotate = xatou_range(opt_b, 0, 99);
 949 #endif
 950 #if ENABLE_FEATURE_IPC_SYSLOG
 951         if (opt_C) // -Cn
 952                 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
 953 #endif
 954         /* If they have not specified remote logging, then log locally */
 955         if (ENABLE_FEATURE_REMOTE_LOG && !(opts & OPT_remotelog)) // -R
 956                 option_mask32 |= OPT_locallog;
 957 #if ENABLE_FEATURE_SYSLOGD_CFG
 958         parse_syslogdcfg(opt_f);
 959 #endif
 960
 961         /* Store away localhost's name before the fork */
 962         G.hostname = safe_gethostname();
 963         *strchrnul(G.hostname, '.') = '\0';
 964
 965         if (!(opts & OPT_nofork)) {
 966                 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
 967         }
 968         //umask(0); - why??
 969         write_pidfile("/var/run/syslogd.pid");
 970         do_syslogd();
 971         /* return EXIT_SUCCESS; */
 972 }
 973
 974 /* Clean up. Needed because we are included from syslogd_and_logger.c */
 975 #undef DEBUG
 976 #undef SYSLOGD_MARK
 977 #undef SYSLOGD_WRLOCK
 978 #undef G
 979 #undef GLOBALS
 980 #undef INIT_G
 981 #undef OPTION_STR
 982 #undef OPTION_DECL
 983 #undef OPTION_PARAM