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 #if ENABLE_FEATURE_ROTATE_LOGFILE
 114         unsigned size;
 115         uint8_t isRegular;
 116 #endif
 117 } logFile_t;
 118
 119 #if ENABLE_FEATURE_SYSLOGD_CFG
 120 typedef struct logRule_t {
 121         uint8_t enabled_facility_priomap[LOG_NFACILITIES];
 122         struct logFile_t *file;
 123         struct logRule_t *next;
 124 } logRule_t;
 125 #endif
 126
 127 /* Allows us to have smaller initializer. Ugly. */
 128 #define GLOBALS \
 129         logFile_t logFile;                      \
 130         /* interval between marks in seconds */ \
 131         /*int markInterval;*/                   \
 132         /* level of messages to be logged */    \
 133         int logLevel;                           \
 134 IF_FEATURE_ROTATE_LOGFILE( \
 135         /* max size of file before rotation */  \
 136         unsigned logFileSize;                   \
 137         /* number of rotated message files */   \
 138         unsigned logFileRotate;                 \
 139 ) \
 140 IF_FEATURE_IPC_SYSLOG( \
 141         int shmid; /* ipc shared memory id */   \
 142         int s_semid; /* ipc semaphore id */     \
 143         int shm_size;                           \
 144         struct sembuf SMwup[1];                 \
 145         struct sembuf SMwdn[3];                 \
 146 ) \
 147 IF_FEATURE_SYSLOGD_CFG( \
 148         logRule_t *log_rules; \
 149 ) \
 150 IF_FEATURE_KMSG_SYSLOG( \
 151         int kmsgfd; \
 152         int primask; \
 153 )
 154
 155 struct init_globals {
 156         GLOBALS
 157 };
 158
 159 struct globals {
 160         GLOBALS
 161
 162 #if ENABLE_FEATURE_REMOTE_LOG
 163         llist_t *remoteHosts;
 164 #endif
 165 #if ENABLE_FEATURE_IPC_SYSLOG
 166         struct shbuf_ds *shbuf;
 167 #endif
 168         time_t last_log_time;
 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 };
 242 #define OPTION_STR "m:nO:l:S" \
 243         IF_FEATURE_ROTATE_LOGFILE("s:" ) \
 244         IF_FEATURE_ROTATE_LOGFILE("b:" ) \
 245         IF_FEATURE_REMOTE_LOG(    "R:" ) \
 246         IF_FEATURE_REMOTE_LOG(    "L"  ) \
 247         IF_FEATURE_IPC_SYSLOG(    "C::") \
 248         IF_FEATURE_SYSLOGD_DUP(   "D"  ) \
 249         IF_FEATURE_SYSLOGD_CFG(   "f:" ) \
 250         IF_FEATURE_KMSG_SYSLOG(   "K"  )
 251 #define OPTION_DECL *opt_m, *opt_l \
 252         IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \
 253         IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \
 254         IF_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL) \
 255         IF_FEATURE_SYSLOGD_CFG(   ,*opt_f = NULL)
 256 #define OPTION_PARAM &opt_m, &(G.logFile.path), &opt_l \
 257         IF_FEATURE_ROTATE_LOGFILE(,&opt_s) \
 258         IF_FEATURE_ROTATE_LOGFILE(,&opt_b) \
 259         IF_FEATURE_REMOTE_LOG(    ,&remoteAddrList) \
 260         IF_FEATURE_IPC_SYSLOG(    ,&opt_C) \
 261         IF_FEATURE_SYSLOGD_CFG(   ,&opt_f)
 262
 263
 264 #if ENABLE_FEATURE_SYSLOGD_CFG
 265 static const CODE* find_by_name(char *name, const CODE* c_set)
 266 {
 267         for (; c_set->c_name; c_set++) {
 268                 if (strcmp(name, c_set->c_name) == 0)
 269                         return c_set;
 270         }
 271         return NULL;
 272 }
 273 #endif
 274 static const CODE* find_by_val(int val, const CODE* c_set)
 275 {
 276         for (; c_set->c_name; c_set++) {
 277                 if (c_set->c_val == val)
 278                         return c_set;
 279         }
 280         return NULL;
 281 }
 282
 283 #if ENABLE_FEATURE_SYSLOGD_CFG
 284 static void parse_syslogdcfg(const char *file)
 285 {
 286         char *t;
 287         logRule_t **pp_rule;
 288         /* tok[0] set of selectors */
 289         /* tok[1] file name */
 290         /* tok[2] has to be NULL */
 291         char *tok[3];
 292         parser_t *parser;
 293
 294         parser = config_open2(file ? file : "/etc/syslog.conf",
 295                                 file ? xfopen_for_read : fopen_for_read);
 296         if (!parser)
 297                 /* didn't find default /etc/syslog.conf */
 298                 /* proceed as if we built busybox without config support */
 299                 return;
 300
 301         /* use ptr to ptr to avoid checking whether head was initialized */
 302         pp_rule = &G.log_rules;
 303         /* iterate through lines of config, skipping comments */
 304         while (config_read(parser, tok, 3, 2, "# \t", PARSE_NORMAL | PARSE_MIN_DIE)) {
 305                 char *cur_selector;
 306                 logRule_t *cur_rule;
 307
 308                 /* unexpected trailing token? */
 309                 if (tok[2])
 310                         goto cfgerr;
 311
 312                 cur_rule = *pp_rule = xzalloc(sizeof(*cur_rule));
 313
 314                 cur_selector = tok[0];
 315                 /* iterate through selectors: "kern.info;kern.!err;..." */
 316                 do {
 317                         const CODE *code;
 318                         char *next_selector;
 319                         uint8_t negated_prio; /* "kern.!err" */
 320                         uint8_t single_prio;  /* "kern.=err" */
 321                         uint32_t facmap; /* bitmap of enabled facilities */
 322                         uint8_t primap;  /* bitmap of enabled priorities */
 323                         unsigned i;
 324
 325                         next_selector = strchr(cur_selector, ';');
 326                         if (next_selector)
 327                                 *next_selector++ = '\0';
 328
 329                         t = strchr(cur_selector, '.');
 330                         if (!t)
 331                                 goto cfgerr;
 332                         *t++ = '\0'; /* separate facility from priority */
 333
 334                         negated_prio = 0;
 335                         single_prio = 0;
 336                         if (*t == '!') {
 337                                 negated_prio = 1;
 338                                 ++t;
 339                         }
 340                         if (*t == '=') {
 341                                 single_prio = 1;
 342                                 ++t;
 343                         }
 344
 345                         /* parse priority */
 346                         if (*t == '*')
 347                                 primap = 0xff; /* all 8 log levels enabled */
 348                         else {
 349                                 uint8_t priority;
 350                                 code = find_by_name(t, prioritynames);
 351                                 if (!code)
 352                                         goto cfgerr;
 353                                 primap = 0;
 354                                 priority = code->c_val;
 355                                 if (priority == INTERNAL_NOPRI) {
 356                                         /* ensure we take "enabled_facility_priomap[fac] &= 0" branch below */
 357                                         negated_prio = 1;
 358                                 } else {
 359                                         priority = 1 << priority;
 360                                         do {
 361                                                 primap |= priority;
 362                                                 if (single_prio)
 363                                                         break;
 364                                                 priority >>= 1;
 365                                         } while (priority);
 366                                         if (negated_prio)
 367                                                 primap = ~primap;
 368                                 }
 369                         }
 370
 371                         /* parse facility */
 372                         if (*cur_selector == '*')
 373                                 facmap = (1<<LOG_NFACILITIES) - 1;
 374                         else {
 375                                 char *next_facility;
 376                                 facmap = 0;
 377                                 t = cur_selector;
 378                                 /* iterate through facilities: "kern,daemon.<priospec>" */
 379                                 do {
 380                                         next_facility = strchr(t, ',');
 381                                         if (next_facility)
 382                                                 *next_facility++ = '\0';
 383                                         code = find_by_name(t, facilitynames);
 384                                         if (!code)
 385                                                 goto cfgerr;
 386                                         /* "mark" is not a real facility, skip it */
 387                                         if (code->c_val != INTERNAL_MARK)
 388                                                 facmap |= 1<<(LOG_FAC(code->c_val));
 389                                         t = next_facility;
 390                                 } while (t);
 391                         }
 392
 393                         /* merge result with previous selectors */
 394                         for (i = 0; i < LOG_NFACILITIES; ++i) {
 395                                 if (!(facmap & (1<<i)))
 396                                         continue;
 397                                 if (negated_prio)
 398                                         cur_rule->enabled_facility_priomap[i] &= primap;
 399                                 else
 400                                         cur_rule->enabled_facility_priomap[i] |= primap;
 401                         }
 402
 403                         cur_selector = next_selector;
 404                 } while (cur_selector);
 405
 406                 /* check whether current file name was mentioned in previous rules or
 407                  * as global logfile (G.logFile).
 408                  */
 409                 if (strcmp(G.logFile.path, tok[1]) == 0) {
 410                         cur_rule->file = &G.logFile;
 411                         goto found;
 412                 }
 413                 /* temporarily use cur_rule as iterator, but *pp_rule still points
 414                  * to currently processing rule entry.
 415                  * NOTE: *pp_rule points to the current (and last in the list) rule.
 416                  */
 417                 for (cur_rule = G.log_rules; cur_rule != *pp_rule; cur_rule = cur_rule->next) {
 418                         if (strcmp(cur_rule->file->path, tok[1]) == 0) {
 419                                 /* found - reuse the same file structure */
 420                                 (*pp_rule)->file = cur_rule->file;
 421                                 cur_rule = *pp_rule;
 422                                 goto found;
 423                         }
 424                 }
 425                 cur_rule->file = xzalloc(sizeof(*cur_rule->file));
 426                 cur_rule->file->fd = -1;
 427                 cur_rule->file->path = xstrdup(tok[1]);
 428  found:
 429                 pp_rule = &cur_rule->next;
 430         }
 431         config_close(parser);
 432         return;
 433
 434  cfgerr:
 435         bb_error_msg_and_die("error in '%s' at line %d",
 436                         file ? file : "/etc/syslog.conf",
 437                         parser->lineno);
 438 }
 439 #endif
 440
 441 /* circular buffer variables/structures */
 442 #if ENABLE_FEATURE_IPC_SYSLOG
 443
 444 #if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
 445 #error Sorry, you must set the syslogd buffer size to at least 4KB.
 446 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 447 #endif
 448
 449 /* our shared key (syslogd.c and logread.c must be in sync) */
 450 enum { KEY_ID = 0x414e4547 }; /* "GENA" */
 451
 452 static void ipcsyslog_cleanup(void)
 453 {
 454         if (G.shmid != -1) {
 455                 shmdt(G.shbuf);
 456         }
 457         if (G.shmid != -1) {
 458                 shmctl(G.shmid, IPC_RMID, NULL);
 459         }
 460         if (G.s_semid != -1) {
 461                 semctl(G.s_semid, 0, IPC_RMID, 0);
 462         }
 463 }
 464
 465 static void ipcsyslog_init(void)
 466 {
 467         if (DEBUG)
 468                 printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
 469
 470         G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
 471         if (G.shmid == -1) {
 472                 bb_perror_msg_and_die("shmget");
 473         }
 474
 475         G.shbuf = shmat(G.shmid, NULL, 0);
 476         if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
 477                 bb_perror_msg_and_die("shmat");
 478         }
 479
 480         memset(G.shbuf, 0, G.shm_size);
 481         G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
 482         /*G.shbuf->tail = 0;*/
 483
 484         /* we'll trust the OS to set initial semval to 0 (let's hope) */
 485         G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
 486         if (G.s_semid == -1) {
 487                 if (errno == EEXIST) {
 488                         G.s_semid = semget(KEY_ID, 2, 0);
 489                         if (G.s_semid != -1)
 490                                 return;
 491                 }
 492                 bb_perror_msg_and_die("semget");
 493         }
 494 }
 495
 496 /* Write message to shared mem buffer */
 497 static void log_to_shmem(const char *msg)
 498 {
 499         int old_tail, new_tail;
 500         int len;
 501
 502         if (semop(G.s_semid, G.SMwdn, 3) == -1) {
 503                 bb_perror_msg_and_die("SMwdn");
 504         }
 505
 506         /* Circular Buffer Algorithm:
 507          * --------------------------
 508          * tail == position where to store next syslog message.
 509          * tail's max value is (shbuf->size - 1)
 510          * Last byte of buffer is never used and remains NUL.
 511          */
 512         len = strlen(msg) + 1; /* length with NUL included */
 513  again:
 514         old_tail = G.shbuf->tail;
 515         new_tail = old_tail + len;
 516         if (new_tail < G.shbuf->size) {
 517                 /* store message, set new tail */
 518                 memcpy(G.shbuf->data + old_tail, msg, len);
 519                 G.shbuf->tail = new_tail;
 520         } else {
 521                 /* k == available buffer space ahead of old tail */
 522                 int k = G.shbuf->size - old_tail;
 523                 /* copy what fits to the end of buffer, and repeat */
 524                 memcpy(G.shbuf->data + old_tail, msg, k);
 525                 msg += k;
 526                 len -= k;
 527                 G.shbuf->tail = 0;
 528                 goto again;
 529         }
 530         if (semop(G.s_semid, G.SMwup, 1) == -1) {
 531                 bb_perror_msg_and_die("SMwup");
 532         }
 533         if (DEBUG)
 534                 printf("tail:%d\n", G.shbuf->tail);
 535 }
 536 #else
 537 static void ipcsyslog_cleanup(void) {}
 538 static void ipcsyslog_init(void) {}
 539 void log_to_shmem(const char *msg);
 540 #endif /* FEATURE_IPC_SYSLOG */
 541
 542 #if ENABLE_FEATURE_KMSG_SYSLOG
 543 static void kmsg_init(void)
 544 {
 545         G.kmsgfd = xopen("/dev/kmsg", O_WRONLY);
 546
 547         /*
 548          * kernel < 3.5 expects single char printk KERN_* priority prefix,
 549          * from 3.5 onwards the full syslog facility/priority format is supported
 550          */
 551         if (get_linux_version_code() < KERNEL_VERSION(3,5,0))
 552                 G.primask = LOG_PRIMASK;
 553         else
 554                 G.primask = -1;
 555 }
 556
 557 static void kmsg_cleanup(void)
 558 {
 559         if (ENABLE_FEATURE_CLEAN_UP)
 560                 close(G.kmsgfd);
 561 }
 562
 563 /* Write message to /dev/kmsg */
 564 static void log_to_kmsg(int pri, const char *msg)
 565 {
 566         /*
 567          * kernel < 3.5 expects single char printk KERN_* priority prefix,
 568          * from 3.5 onwards the full syslog facility/priority format is supported
 569          */
 570         pri &= G.primask;
 571
 572         write(G.kmsgfd, G.printbuf, sprintf(G.printbuf, "<%d>%s\n", pri, msg));
 573 }
 574 #else
 575 static void kmsg_init(void) {}
 576 static void kmsg_cleanup(void) {}
 577 static void log_to_kmsg(int pri UNUSED_PARAM, const char *msg UNUSED_PARAM) {}
 578 #endif /* FEATURE_KMSG_SYSLOG */
 579
 580 /* Print a message to the log file. */
 581 static void log_locally(time_t now, char *msg, logFile_t *log_file)
 582 {
 583 #ifdef SYSLOGD_WRLOCK
 584         struct flock fl;
 585 #endif
 586         int len = strlen(msg);
 587
 588         /* fd can't be 0 (we connect fd 0 to /dev/log socket) */
 589         /* fd is 1 if "-O -" is in use */
 590         if (log_file->fd > 1) {
 591                 /* Reopen log file every second. This allows admin
 592                  * to delete the file and not worry about restarting us.
 593                  * This costs almost nothing since it happens
 594                  * _at most_ once a second.
 595                  */
 596                 if (!now)
 597                         now = time(NULL);
 598                 if (G.last_log_time != now) {
 599                         G.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         log_file->size +=
 682 #endif
 683                         full_write(log_file->fd, msg, len);
 684 #ifdef SYSLOGD_WRLOCK
 685         fl.l_type = F_UNLCK;
 686         fcntl(log_file->fd, F_SETLKW, &fl);
 687 #endif
 688 }
 689
 690 static void parse_fac_prio_20(int pri, char *res20)
 691 {
 692         const CODE *c_pri, *c_fac;
 693
 694         c_fac = find_by_val(LOG_FAC(pri) << 3, facilitynames);
 695         if (c_fac) {
 696                 c_pri = find_by_val(LOG_PRI(pri), prioritynames);
 697                 if (c_pri) {
 698                         snprintf(res20, 20, "%s.%s", c_fac->c_name, c_pri->c_name);
 699                         return;
 700                 }
 701         }
 702         snprintf(res20, 20, "<%d>", pri);
 703 }
 704
 705 /* len parameter is used only for "is there a timestamp?" check.
 706  * NB: some callers cheat and supply len==0 when they know
 707  * that there is no timestamp, short-circuiting the test. */
 708 static void timestamp_and_log(int pri, char *msg, int len)
 709 {
 710         char *timestamp;
 711         time_t now;
 712
 713         /* Jan 18 00:11:22 msg... */
 714         /* 01234567890123456 */
 715         if (len < 16 || msg[3] != ' ' || msg[6] != ' '
 716          || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
 717         ) {
 718                 time(&now);
 719                 timestamp = ctime(&now) + 4; /* skip day of week */
 720         } else {
 721                 now = 0;
 722                 timestamp = msg;
 723                 msg += 16;
 724         }
 725         timestamp[15] = '\0';
 726
 727         if (option_mask32 & OPT_kmsg) {
 728                 log_to_kmsg(pri, msg);
 729                 return;
 730         }
 731
 732         if (option_mask32 & OPT_small)
 733                 sprintf(G.printbuf, "%s %s\n", timestamp, msg);
 734         else {
 735                 char res[20];
 736                 parse_fac_prio_20(pri, res);
 737                 sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
 738         }
 739
 740         /* Log message locally (to file or shared mem) */
 741 #if ENABLE_FEATURE_SYSLOGD_CFG
 742         {
 743                 bool match = 0;
 744                 logRule_t *rule;
 745                 uint8_t facility = LOG_FAC(pri);
 746                 uint8_t prio_bit = 1 << LOG_PRI(pri);
 747
 748                 for (rule = G.log_rules; rule; rule = rule->next) {
 749                         if (rule->enabled_facility_priomap[facility] & prio_bit) {
 750                                 log_locally(now, G.printbuf, rule->file);
 751                                 match = 1;
 752                         }
 753                 }
 754                 if (match)
 755                         return;
 756         }
 757 #endif
 758         if (LOG_PRI(pri) < G.logLevel) {
 759 #if ENABLE_FEATURE_IPC_SYSLOG
 760                 if ((option_mask32 & OPT_circularlog) && G.shbuf) {
 761                         log_to_shmem(G.printbuf);
 762                         return;
 763                 }
 764 #endif
 765                 log_locally(now, G.printbuf, &G.logFile);
 766         }
 767 }
 768
 769 static void timestamp_and_log_internal(const char *msg)
 770 {
 771         /* -L, or no -R */
 772         if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
 773                 return;
 774         timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
 775 }
 776
 777 /* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
 778  * embedded NULs. Split messages on each of these NULs, parse prio,
 779  * escape control chars and log each locally. */
 780 static void split_escape_and_log(char *tmpbuf, int len)
 781 {
 782         char *p = tmpbuf;
 783
 784         tmpbuf += len;
 785         while (p < tmpbuf) {
 786                 char c;
 787                 char *q = G.parsebuf;
 788                 int pri = (LOG_USER | LOG_NOTICE);
 789
 790                 if (*p == '<') {
 791                         /* Parse the magic priority number */
 792                         pri = bb_strtou(p + 1, &p, 10);
 793                         if (*p == '>')
 794                                 p++;
 795                         if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 796                                 pri = (LOG_USER | LOG_NOTICE);
 797                 }
 798
 799                 while ((c = *p++)) {
 800                         if (c == '\n')
 801                                 c = ' ';
 802                         if (!(c & ~0x1f) && c != '\t') {
 803                                 *q++ = '^';
 804                                 c += '@'; /* ^@, ^A, ^B... */
 805                         }
 806                         *q++ = c;
 807                 }
 808                 *q = '\0';
 809
 810                 /* Now log it */
 811                 timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
 812         }
 813 }
 814
 815 #ifdef SYSLOGD_MARK
 816 static void do_mark(int sig)
 817 {
 818         if (G.markInterval) {
 819                 timestamp_and_log_internal("-- MARK --");
 820                 alarm(G.markInterval);
 821         }
 822 }
 823 #endif
 824
 825 /* Don't inline: prevent struct sockaddr_un to take up space on stack
 826  * permanently */
 827 static NOINLINE int create_socket(void)
 828 {
 829         struct sockaddr_un sunx;
 830         int sock_fd;
 831         char *dev_log_name;
 832
 833 #if ENABLE_FEATURE_SYSTEMD
 834         if (sd_listen_fds() == 1)
 835                 return SD_LISTEN_FDS_START;
 836 #endif
 837
 838         memset(&sunx, 0, sizeof(sunx));
 839         sunx.sun_family = AF_UNIX;
 840
 841         /* Unlink old /dev/log or object it points to. */
 842         /* (if it exists, bind will fail) */
 843         strcpy(sunx.sun_path, _PATH_LOG);
 844         dev_log_name = xmalloc_follow_symlinks(_PATH_LOG);
 845         if (dev_log_name) {
 846                 safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
 847                 free(dev_log_name);
 848         }
 849         unlink(sunx.sun_path);
 850
 851         sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
 852         xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
 853         chmod(_PATH_LOG, 0666);
 854
 855         return sock_fd;
 856 }
 857
 858 #if ENABLE_FEATURE_REMOTE_LOG
 859 static int try_to_resolve_remote(remoteHost_t *rh)
 860 {
 861         if (!rh->remoteAddr) {
 862                 unsigned now = monotonic_sec();
 863
 864                 /* Don't resolve name too often - DNS timeouts can be big */
 865                 if ((now - rh->last_dns_resolve) < DNS_WAIT_SEC)
 866                         return -1;
 867                 rh->last_dns_resolve = now;
 868                 rh->remoteAddr = host2sockaddr(rh->remoteHostname, 514);
 869                 if (!rh->remoteAddr)
 870                         return -1;
 871         }
 872         return xsocket(rh->remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
 873 }
 874 #endif
 875
 876 static void do_syslogd(void) NORETURN;
 877 static void do_syslogd(void)
 878 {
 879 #if ENABLE_FEATURE_REMOTE_LOG
 880         llist_t *item;
 881 #endif
 882 #if ENABLE_FEATURE_SYSLOGD_DUP
 883         int last_sz = -1;
 884         char *last_buf;
 885         char *recvbuf = G.recvbuf;
 886 #else
 887 #define recvbuf (G.recvbuf)
 888 #endif
 889
 890         /* Set up signal handlers (so that they interrupt read()) */
 891         signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo);
 892         signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
 893         //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo);
 894         signal(SIGHUP, SIG_IGN);
 895 #ifdef SYSLOGD_MARK
 896         signal(SIGALRM, do_mark);
 897         alarm(G.markInterval);
 898 #endif
 899         xmove_fd(create_socket(), STDIN_FILENO);
 900
 901         if (option_mask32 & OPT_circularlog)
 902                 ipcsyslog_init();
 903
 904         if (option_mask32 & OPT_kmsg)
 905                 kmsg_init();
 906
 907         timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
 908
 909         while (!bb_got_signal) {
 910                 ssize_t sz;
 911
 912 #if ENABLE_FEATURE_SYSLOGD_DUP
 913                 last_buf = recvbuf;
 914                 if (recvbuf == G.recvbuf)
 915                         recvbuf = G.recvbuf + MAX_READ;
 916                 else
 917                         recvbuf = G.recvbuf;
 918 #endif
 919  read_again:
 920                 sz = read(STDIN_FILENO, recvbuf, MAX_READ - 1);
 921                 if (sz < 0) {
 922                         if (!bb_got_signal)
 923                                 bb_perror_msg("read from %s", _PATH_LOG);
 924                         break;
 925                 }
 926
 927                 /* Drop trailing '\n' and NULs (typically there is one NUL) */
 928                 while (1) {
 929                         if (sz == 0)
 930                                 goto read_again;
 931                         /* man 3 syslog says: "A trailing newline is added when needed".
 932                          * However, neither glibc nor uclibc do this:
 933                          * syslog(prio, "test")   sends "test\0" to /dev/log,
 934                          * syslog(prio, "test\n") sends "test\n\0".
 935                          * IOW: newline is passed verbatim!
 936                          * I take it to mean that it's syslogd's job
 937                          * to make those look identical in the log files. */
 938                         if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
 939                                 break;
 940                         sz--;
 941                 }
 942 #if ENABLE_FEATURE_SYSLOGD_DUP
 943                 if ((option_mask32 & OPT_dup) && (sz == last_sz))
 944                         if (memcmp(last_buf, recvbuf, sz) == 0)
 945                                 continue;
 946                 last_sz = sz;
 947 #endif
 948 #if ENABLE_FEATURE_REMOTE_LOG
 949                 /* Stock syslogd sends it '\n'-terminated
 950                  * over network, mimic that */
 951                 recvbuf[sz] = '\n';
 952
 953                 /* We are not modifying log messages in any way before send */
 954                 /* Remote site cannot trust _us_ anyway and need to do validation again */
 955                 for (item = G.remoteHosts; item != NULL; item = item->link) {
 956                         remoteHost_t *rh = (remoteHost_t *)item->data;
 957
 958                         if (rh->remoteFD == -1) {
 959                                 rh->remoteFD = try_to_resolve_remote(rh);
 960                                 if (rh->remoteFD == -1)
 961                                         continue;
 962                         }
 963
 964                         /* Send message to remote logger.
 965                          * On some errors, close and set remoteFD to -1
 966                          * so that DNS resolution is retried.
 967                          */
 968                         if (sendto(rh->remoteFD, recvbuf, sz+1,
 969                                         MSG_DONTWAIT | MSG_NOSIGNAL,
 970                                         &(rh->remoteAddr->u.sa), rh->remoteAddr->len) == -1
 971                         ) {
 972                                 switch (errno) {
 973                                 case ECONNRESET:
 974                                 case ENOTCONN: /* paranoia */
 975                                 case EPIPE:
 976                                         close(rh->remoteFD);
 977                                         rh->remoteFD = -1;
 978                                         free(rh->remoteAddr);
 979                                         rh->remoteAddr = NULL;
 980                                 }
 981                         }
 982                 }
 983 #endif
 984                 if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
 985                         recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
 986                         split_escape_and_log(recvbuf, sz);
 987                 }
 988         } /* while (!bb_got_signal) */
 989
 990         timestamp_and_log_internal("syslogd exiting");
 991         remove_pidfile(CONFIG_PID_FILE_PATH "/syslogd.pid");
 992         ipcsyslog_cleanup();
 993         if (option_mask32 & OPT_kmsg)
 994                 kmsg_cleanup();
 995         kill_myself_with_sig(bb_got_signal);
 996 #undef recvbuf
 997 }
 998
 999 int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1000 int syslogd_main(int argc UNUSED_PARAM, char **argv)
1001 {
1002         int opts;
1003         char OPTION_DECL;
1004 #if ENABLE_FEATURE_REMOTE_LOG
1005         llist_t *remoteAddrList = NULL;
1006 #endif
1007
1008         INIT_G();
1009
1010         /* No non-option params, -R can occur multiple times */
1011         opt_complementary = "=0" IF_FEATURE_REMOTE_LOG(":R::");
1012         opts = getopt32(argv, OPTION_STR, OPTION_PARAM);
1013 #if ENABLE_FEATURE_REMOTE_LOG
1014         while (remoteAddrList) {
1015                 remoteHost_t *rh = xzalloc(sizeof(*rh));
1016                 rh->remoteHostname = llist_pop(&remoteAddrList);
1017                 rh->remoteFD = -1;
1018                 rh->last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
1019                 llist_add_to(&G.remoteHosts, rh);
1020         }
1021 #endif
1022
1023 #ifdef SYSLOGD_MARK
1024         if (opts & OPT_mark) // -m
1025                 G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
1026 #endif
1027         //if (opts & OPT_nofork) // -n
1028         //if (opts & OPT_outfile) // -O
1029         if (opts & OPT_loglevel) // -l
1030                 G.logLevel = xatou_range(opt_l, 1, 8);
1031         //if (opts & OPT_small) // -S
1032 #if ENABLE_FEATURE_ROTATE_LOGFILE
1033         if (opts & OPT_filesize) // -s
1034                 G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
1035         if (opts & OPT_rotatecnt) // -b
1036                 G.logFileRotate = xatou_range(opt_b, 0, 99);
1037 #endif
1038 #if ENABLE_FEATURE_IPC_SYSLOG
1039         if (opt_C) // -Cn
1040                 G.shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
1041 #endif
1042         /* If they have not specified remote logging, then log locally */
1043         if (ENABLE_FEATURE_REMOTE_LOG && !(opts & OPT_remotelog)) // -R
1044                 option_mask32 |= OPT_locallog;
1045 #if ENABLE_FEATURE_SYSLOGD_CFG
1046         parse_syslogdcfg(opt_f);
1047 #endif
1048
1049         /* Store away localhost's name before the fork */
1050         G.hostname = safe_gethostname();
1051         *strchrnul(G.hostname, '.') = '\0';
1052
1053         if (!(opts & OPT_nofork)) {
1054                 bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
1055         }
1056
1057         //umask(0); - why??
1058         write_pidfile(CONFIG_PID_FILE_PATH "/syslogd.pid");
1059
1060         do_syslogd();
1061         /* return EXIT_SUCCESS; */
1062 }
1063
1064 /* Clean up. Needed because we are included from syslogd_and_logger.c */
1065 #undef DEBUG
1066 #undef SYSLOGD_MARK
1067 #undef SYSLOGD_WRLOCK
1068 #undef G
1069 #undef GLOBALS
1070 #undef INIT_G
1071 #undef OPTION_STR
1072 #undef OPTION_DECL
1073 #undef OPTION_PARAM