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