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