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