syslogd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini syslogd implementation for busybox
   4  *
   5  * Copyright (C) 1999 by Lineo, inc.
   6  * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  *
  22  */
  23
  24 #include "internal.h"
  25 #include <ctype.h>
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <netdb.h>
  29 #include <paths.h>
  30 #include <signal.h>
  31 #include <stdarg.h>
  32 #include <stdio.h>
  33 #include <sys/klog.h>
  34 #include <sys/socket.h>
  35 #include <sys/stat.h>
  36 #include <sys/types.h>
  37 #include <sys/un.h>
  38 #include <time.h>
  39 #include <unistd.h>
  40
  41 #define ksyslog klogctl
  42 extern int ksyslog(int type, char *buf, int len);
  43
  44
  45 /* SYSLOG_NAMES defined to pull some extra junk from syslog.h */
  46 #define SYSLOG_NAMES
  47 #include <sys/syslog.h>
  48
  49 /* Path for the file where all log messages are written */
  50 #define __LOG_FILE "/var/log/messages"
  51
  52 /* Path to the unix socket */
  53 char lfile[PATH_MAX] = "";
  54
  55 static char *logFilePath = __LOG_FILE;
  56
  57 /* interval between marks in seconds */
  58 static int MarkInterval = 20 * 60;
  59
  60 /* localhost's name */
  61 static char LocalHostName[32];
  62
  63 static const char syslogd_usage[] =
  64         "syslogd [OPTION]...\n\n"
  65         "Linux system and kernel (provides klogd) logging utility.\n"
  66         "Note that this version of syslogd/klogd ignores /etc/syslog.conf.\n\n"
  67         "Options:\n"
  68         "\t-m\tChange the mark timestamp interval. default=20min. 0=off\n"
  69         "\t-n\tDo not fork into the background (for when run by init)\n"
  70 #ifdef BB_KLOGD
  71         "\t-K\tDo not start up the klogd process (by default syslogd spawns klogd).\n"
  72 #endif
  73         "\t-O\tSpecify an alternate log file.  default=/var/log/messages\n";
  74
  75 /* Note: There is also a function called "message()" in init.c */
  76 /* Print a message to the log file. */
  77 static void message(char *fmt, ...)
  78 {
  79         int fd;
  80         va_list arguments;
  81
  82         if (
  83                 (fd =
  84                  device_open(logFilePath,
  85                                          O_WRONLY | O_CREAT | O_NOCTTY | O_APPEND |
  86                                          O_NONBLOCK)) >= 0) {
  87                 va_start(arguments, fmt);
  88                 vdprintf(fd, fmt, arguments);
  89                 va_end(arguments);
  90                 close(fd);
  91         } else {
  92                 /* Always send console messages to /dev/console so people will see them. */
  93                 if (
  94                         (fd =
  95                          device_open(_PATH_CONSOLE,
  96                                                  O_WRONLY | O_NOCTTY | O_NONBLOCK)) >= 0) {
  97                         va_start(arguments, fmt);
  98                         vdprintf(fd, fmt, arguments);
  99                         va_end(arguments);
 100                         close(fd);
 101                 } else {
 102                         fprintf(stderr, "Bummer, can't print: ");
 103                         va_start(arguments, fmt);
 104                         vfprintf(stderr, fmt, arguments);
 105                         fflush(stderr);
 106                         va_end(arguments);
 107                 }
 108         }
 109 }
 110
 111 static void logMessage(int pri, char *msg)
 112 {
 113         time_t now;
 114         char *timestamp;
 115         static char res[20] = "";
 116         CODE *c_pri, *c_fac;
 117
 118         if (pri != 0) {
 119                 for (c_fac = facilitynames;
 120                          c_fac->c_name && !(c_fac->c_val == LOG_FAC(pri) << 3); c_fac++);
 121                 for (c_pri = prioritynames;
 122                          c_pri->c_name && !(c_pri->c_val == LOG_PRI(pri)); c_pri++);
 123                 if (*c_fac->c_name == '\0' || *c_pri->c_name == '\0')
 124                         snprintf(res, sizeof(res), "<%d>", pri);
 125                 else
 126                         snprintf(res, sizeof(res), "%s.%s", c_fac->c_name, c_pri->c_name);
 127         }
 128
 129         if (strlen(msg) < 16 || msg[3] != ' ' || msg[6] != ' ' ||
 130                 msg[9] != ':' || msg[12] != ':' || msg[15] != ' ') {
 131                 time(&now);
 132                 timestamp = ctime(&now) + 4;
 133                 timestamp[15] = '\0';
 134         } else {
 135                 timestamp = msg;
 136                 timestamp[15] = '\0';
 137                 msg += 16;
 138         }
 139
 140         /* todo: supress duplicates */
 141
 142         /* now spew out the message to wherever it is supposed to go */
 143         message("%s %s %s %s\n", timestamp, LocalHostName, res, msg);
 144 }
 145
 146 static void quit_signal(int sig)
 147 {
 148         logMessage(0, "System log daemon exiting.");
 149         unlink(lfile);
 150         exit(TRUE);
 151 }
 152
 153 static void domark(int sig)
 154 {
 155         if (MarkInterval > 0) {
 156                 logMessage(LOG_SYSLOG | LOG_INFO, "-- MARK --");
 157                 alarm(MarkInterval);
 158         }
 159 }
 160
 161 static void doSyslogd (void) __attribute__ ((noreturn));
 162 static void doSyslogd (void)
 163 {
 164         struct sockaddr_un sunx;
 165         size_t addrLength;
 166         int sock_fd;
 167         fd_set readfds;
 168         char lfile[PATH_MAX];
 169         int t = readlink(_PATH_LOG, lfile, sizeof(lfile) - 1); /* Resolve symlinks */
 170
 171         /* Set up sig handlers */
 172         signal (SIGINT,  quit_signal);
 173         signal (SIGTERM, quit_signal);
 174         signal (SIGQUIT, quit_signal);
 175         signal (SIGHUP,  SIG_IGN);
 176         signal (SIGALRM, domark);
 177         alarm (MarkInterval);
 178
 179         if (t == -1)
 180                 strncpy(lfile, _PATH_LOG, sizeof(lfile));
 181         else
 182                 lfile[t] = '\0';
 183
 184         unlink (lfile);
 185
 186         memset (&sunx, 0, sizeof(sunx));
 187
 188         sunx.sun_family = AF_UNIX;
 189         strncpy (sunx.sun_path, lfile, sizeof(sunx.sun_path));
 190         if ((sock_fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 191                 perror ("Couldn't obtain descriptor for socket " _PATH_LOG);
 192                 exit (FALSE);
 193         }
 194
 195         addrLength = sizeof (sunx.sun_family) + strlen (sunx.sun_path);
 196         if ((bind (sock_fd, (struct sockaddr *) &sunx, addrLength)) ||
 197                 (listen (sock_fd, 5))) {
 198                 perror ("Could not connect to socket " _PATH_LOG);
 199                 exit (FALSE);
 200         }
 201
 202         if (chmod (lfile, 0666) < 0) {
 203                 perror ("Could not set permission on " _PATH_LOG);
 204                 exit (FALSE);
 205         }
 206
 207         FD_ZERO (&readfds);
 208         FD_SET (sock_fd, &readfds);
 209
 210         logMessage (0, "syslogd started: BusyBox v" BB_VER " (" BB_BT ")");
 211
 212         for (;;) {
 213                 int n_ready;
 214                 int fd;
 215
 216                 if ((n_ready = select (FD_SETSIZE, &readfds, NULL, NULL, NULL)) < 0) {
 217                         if (errno == EINTR) continue; /* alarm may have happened. */
 218                         perror ("select");
 219                         exit (FALSE);
 220                 }
 221
 222                 /* Skip stdin, stdout, stderr */
 223                 for (fd = 3; fd <= FD_SETSIZE; fd++) {
 224                         if (FD_ISSET (fd, &readfds)) {
 225                                 if (fd == sock_fd) {
 226                                         int conn;
 227                                         if ((conn = accept(sock_fd, (struct sockaddr *) &sunx,
 228                                                                            &addrLength)) < 0) {
 229                                                 perror ("accept");
 230                                                 exit (FALSE); /* #### ??? */
 231                                         }
 232                                         FD_SET (conn, &readfds);
 233                                 }
 234                                 else {
 235 #define                   BUFSIZE 1024 + 1
 236                                         char buf[BUFSIZE];
 237                                         char *q, *p;
 238                                         int n_read;
 239
 240                                         n_read = read (fd, buf, BUFSIZE);
 241
 242                                         if (n_read < 0) {
 243                                                 perror ("read error");
 244                                                 goto close_fd;
 245                                         }
 246                                         else if (n_read > 0) {
 247                                                 char line[BUFSIZE];
 248                                                 unsigned char c;
 249                                                 int pri = (LOG_USER | LOG_NOTICE);
 250
 251                                                 memset (line, 0, sizeof(line));
 252                                                 p = buf;
 253                                                 q = line;
 254                                                 while (p && (c = *p) && q < &line[sizeof(line) - 1]) {
 255                                                         if (c == '<') {
 256                                                                 /* Parse the magic priority number */
 257                                                                 pri = 0;
 258                                                                 while (isdigit(*(++p))) {
 259                                                                         pri = 10 * pri + (*p - '0');
 260                                                                 }
 261                                                                 if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 262                                                                         pri = (LOG_USER | LOG_NOTICE);
 263                                                         } else if (c == '\n') {
 264                                                                 *q++ = ' ';
 265                                                         } else if (iscntrl(c) && (c < 0177)) {
 266                                                                 *q++ = '^';
 267                                                                 *q++ = c ^ 0100;
 268                                                         } else {
 269                                                                 *q++ = c;
 270                                                         }
 271                                                         p++;
 272                                                 }
 273                                                 *q = '\0';
 274
 275                                                 /* Now log it */
 276                                                 logMessage(pri, line);
 277
 278                                         close_fd:
 279                                                 close (fd);
 280                                                 FD_CLR (fd, &readfds);
 281                                         }
 282                                         else {          /* EOF */
 283                                                 goto close_fd;
 284                                         }
 285                                 }
 286                         }
 287                 }
 288         }
 289 }
 290
 291 #ifdef BB_KLOGD
 292
 293 static void klogd_signal(int sig)
 294 {
 295         ksyslog(7, NULL, 0);
 296         ksyslog(0, 0, 0);
 297         logMessage(0, "Kernel log daemon exiting.");
 298         exit(TRUE);
 299 }
 300
 301 static void doKlogd (void) __attribute__ ((noreturn));
 302 static void doKlogd (void)
 303 {
 304         int priority = LOG_INFO;
 305         char log_buffer[4096];
 306         char *logp;
 307
 308         /* Set up sig handlers */
 309         signal(SIGINT, klogd_signal);
 310         signal(SIGKILL, klogd_signal);
 311         signal(SIGTERM, klogd_signal);
 312         signal(SIGHUP, SIG_IGN);
 313         logMessage(0, "klogd started: "
 314                            "BusyBox v" BB_VER " (" BB_BT ")");
 315
 316         ksyslog(1, NULL, 0);
 317
 318         while (1) {
 319                 /* Use kernel syscalls */
 320                 memset(log_buffer, '\0', sizeof(log_buffer));
 321                 if (ksyslog(2, log_buffer, sizeof(log_buffer)) < 0) {
 322                         char message[80];
 323
 324                         if (errno == EINTR)
 325                                 continue;
 326                         snprintf(message, 79, "klogd: Error return from sys_sycall: " \
 327                                          "%d - %s.\n", errno, strerror(errno));
 328                         logMessage(LOG_SYSLOG | LOG_ERR, message);
 329                         exit(1);
 330                 }
 331                 logp = log_buffer;
 332                 if (*log_buffer == '<') {
 333                         switch (*(log_buffer + 1)) {
 334                         case '0':
 335                                 priority = LOG_EMERG;
 336                                 break;
 337                         case '1':
 338                                 priority = LOG_ALERT;
 339                                 break;
 340                         case '2':
 341                                 priority = LOG_CRIT;
 342                                 break;
 343                         case '3':
 344                                 priority = LOG_ERR;
 345                                 break;
 346                         case '4':
 347                                 priority = LOG_WARNING;
 348                                 break;
 349                         case '5':
 350                                 priority = LOG_NOTICE;
 351                                 break;
 352                         case '6':
 353                                 priority = LOG_INFO;
 354                                 break;
 355                         case '7':
 356                         default:
 357                                 priority = LOG_DEBUG;
 358                         }
 359                         logp += 3;
 360                 }
 361                 logMessage(LOG_KERN | priority, logp);
 362         }
 363
 364 }
 365
 366 #endif
 367
 368 static void daemon_init (char **argv, char *dz, void fn (void)) __attribute__ ((noreturn));
 369 static void daemon_init (char **argv, char *dz, void fn (void))
 370 {
 371         setsid();
 372         chdir ("/");
 373         strncpy(argv[0], dz, strlen(argv[0]));
 374         fn();
 375         exit(0);
 376 }
 377
 378 extern int syslogd_main(int argc, char **argv)
 379 {
 380         int pid, klogd_pid;
 381         int doFork = TRUE;
 382
 383 #ifdef BB_KLOGD
 384         int startKlogd = TRUE;
 385 #endif
 386         int stopDoingThat = FALSE;
 387         char *p;
 388         char **argv1 = argv;
 389
 390         while (--argc > 0 && **(++argv1) == '-') {
 391                 stopDoingThat = FALSE;
 392                 while (stopDoingThat == FALSE && *(++(*argv1))) {
 393                         switch (**argv1) {
 394                         case 'm':
 395                                 if (--argc == 0) {
 396                                         usage(syslogd_usage);
 397                                 }
 398                                 MarkInterval = atoi(*(++argv1)) * 60;
 399                                 break;
 400                         case 'n':
 401                                 doFork = FALSE;
 402                                 break;
 403 #ifdef BB_KLOGD
 404                         case 'K':
 405                                 startKlogd = FALSE;
 406                                 break;
 407 #endif
 408                         case 'O':
 409                                 if (--argc == 0) {
 410                                         usage(syslogd_usage);
 411                                 }
 412                                 logFilePath = *(++argv1);
 413                                 stopDoingThat = TRUE;
 414                                 break;
 415                         default:
 416                                 usage(syslogd_usage);
 417                         }
 418                 }
 419         }
 420
 421         /* Store away localhost's name before the fork */
 422         gethostname(LocalHostName, sizeof(LocalHostName));
 423         if ((p = strchr(LocalHostName, '.'))) {
 424                 *p++ = '\0';
 425         }
 426
 427         umask(0);
 428
 429 #ifdef BB_KLOGD
 430         /* Start up the klogd process */
 431         if (startKlogd == TRUE) {
 432                 klogd_pid = fork();
 433                 if (klogd_pid == 0) {
 434                         daemon_init (argv, "klogd", doKlogd);
 435                 }
 436         }
 437 #endif
 438
 439         if (doFork == TRUE) {
 440                 pid = fork();
 441                 if (pid < 0)
 442                         exit(pid);
 443                 else if (pid == 0) {
 444                         daemon_init (argv, "syslogd", doSyslogd);
 445                 }
 446         } else {
 447                 doSyslogd();
 448         }
 449
 450         exit(TRUE);
 451 }
 452
 453 /*
 454  * Local Variables
 455  * c-file-style: "linux"
 456  * c-basic-offset: 4
 457  * tab-width: 4
 458  * End:
 459  */