sysklogd/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                    __attribute__ ((format (printf, 1, 2)));
  79 static void message(char *fmt, ...)
  80 {
  81         int fd;
  82         va_list arguments;
  83
  84         if (
  85                 (fd =
  86                  device_open(logFilePath,
  87                                          O_WRONLY | O_CREAT | O_NOCTTY | O_APPEND |
  88                                          O_NONBLOCK)) >= 0) {
  89                 va_start(arguments, fmt);
  90                 vdprintf(fd, fmt, arguments);
  91                 va_end(arguments);
  92                 close(fd);
  93         } else {
  94                 /* Always send console messages to /dev/console so people will see them. */
  95                 if (
  96                         (fd =
  97                          device_open(_PATH_CONSOLE,
  98                                                  O_WRONLY | O_NOCTTY | O_NONBLOCK)) >= 0) {
  99                         va_start(arguments, fmt);
 100                         vdprintf(fd, fmt, arguments);
 101                         va_end(arguments);
 102                         close(fd);
 103                 } else {
 104                         fprintf(stderr, "Bummer, can't print: ");
 105                         va_start(arguments, fmt);
 106                         vfprintf(stderr, fmt, arguments);
 107                         fflush(stderr);
 108                         va_end(arguments);
 109                 }
 110         }
 111 }
 112
 113 static void logMessage(int pri, char *msg)
 114 {
 115         time_t now;
 116         char *timestamp;
 117         static char res[20] = "";
 118         CODE *c_pri, *c_fac;
 119
 120         if (pri != 0) {
 121                 for (c_fac = facilitynames;
 122                          c_fac->c_name && !(c_fac->c_val == LOG_FAC(pri) << 3); c_fac++);
 123                 for (c_pri = prioritynames;
 124                          c_pri->c_name && !(c_pri->c_val == LOG_PRI(pri)); c_pri++);
 125                 if (*c_fac->c_name == '\0' || *c_pri->c_name == '\0')
 126                         snprintf(res, sizeof(res), "<%d>", pri);
 127                 else
 128                         snprintf(res, sizeof(res), "%s.%s", c_fac->c_name, c_pri->c_name);
 129         }
 130
 131         if (strlen(msg) < 16 || msg[3] != ' ' || msg[6] != ' ' ||
 132                 msg[9] != ':' || msg[12] != ':' || msg[15] != ' ') {
 133                 time(&now);
 134                 timestamp = ctime(&now) + 4;
 135                 timestamp[15] = '\0';
 136         } else {
 137                 timestamp = msg;
 138                 timestamp[15] = '\0';
 139                 msg += 16;
 140         }
 141
 142         /* todo: supress duplicates */
 143
 144         /* now spew out the message to wherever it is supposed to go */
 145         message("%s %s %s %s\n", timestamp, LocalHostName, res, msg);
 146 }
 147
 148 static void quit_signal(int sig)
 149 {
 150         logMessage(0, "System log daemon exiting.");
 151         unlink(lfile);
 152         exit(TRUE);
 153 }
 154
 155 static void domark(int sig)
 156 {
 157         if (MarkInterval > 0) {
 158                 logMessage(LOG_SYSLOG | LOG_INFO, "-- MARK --");
 159                 alarm(MarkInterval);
 160         }
 161 }
 162
 163 static void doSyslogd (void) __attribute__ ((noreturn));
 164 static void doSyslogd (void)
 165 {
 166         struct sockaddr_un sunx;
 167         size_t addrLength;
 168         int sock_fd;
 169         fd_set readfds;
 170         char lfile[PATH_MAX];
 171         int t = readlink(_PATH_LOG, lfile, sizeof(lfile) - 1); /* Resolve symlinks */
 172
 173         /* Set up sig handlers */
 174         signal (SIGINT,  quit_signal);
 175         signal (SIGTERM, quit_signal);
 176         signal (SIGQUIT, quit_signal);
 177         signal (SIGHUP,  SIG_IGN);
 178         signal (SIGALRM, domark);
 179         alarm (MarkInterval);
 180
 181         if (t == -1)
 182                 strncpy(lfile, _PATH_LOG, sizeof(lfile));
 183         else
 184                 lfile[t] = '\0';
 185
 186         unlink (lfile);
 187
 188         memset (&sunx, 0, sizeof(sunx));
 189
 190         sunx.sun_family = AF_UNIX;
 191         strncpy (sunx.sun_path, lfile, sizeof(sunx.sun_path));
 192         if ((sock_fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 193                 perror ("Couldn't obtain descriptor for socket " _PATH_LOG);
 194                 exit (FALSE);
 195         }
 196
 197         addrLength = sizeof (sunx.sun_family) + strlen (sunx.sun_path);
 198         if ((bind (sock_fd, (struct sockaddr *) &sunx, addrLength)) ||
 199                 (listen (sock_fd, 5))) {
 200                 perror ("Could not connect to socket " _PATH_LOG);
 201                 exit (FALSE);
 202         }
 203
 204         if (chmod (lfile, 0666) < 0) {
 205                 perror ("Could not set permission on " _PATH_LOG);
 206                 exit (FALSE);
 207         }
 208
 209         FD_ZERO (&readfds);
 210         FD_SET (sock_fd, &readfds);
 211
 212         logMessage (0, "syslogd started: BusyBox v" BB_VER " (" BB_BT ")");
 213
 214         for (;;) {
 215                 int n_ready;
 216                 int fd;
 217
 218                 if ((n_ready = select (FD_SETSIZE, &readfds, NULL, NULL, NULL)) < 0) {
 219                         if (errno == EINTR) continue; /* alarm may have happened. */
 220                         perror ("select");
 221                         exit (FALSE);
 222                 }
 223
 224                 /* Skip stdin, stdout, stderr */
 225                 for (fd = 3; fd <= FD_SETSIZE; fd++) {
 226                         if (FD_ISSET (fd, &readfds)) {
 227                                 if (fd == sock_fd) {
 228                                         int conn;
 229                                         if ((conn = accept(sock_fd, (struct sockaddr *) &sunx,
 230                                                                            &addrLength)) < 0) {
 231                                                 perror ("accept");
 232                                                 exit (FALSE); /* #### ??? */
 233                                         }
 234                                         FD_SET (conn, &readfds);
 235                                 }
 236                                 else {
 237 #define                   BUFSIZE 1024 + 1
 238                                         char buf[BUFSIZE];
 239                                         char *q, *p;
 240                                         int n_read;
 241
 242                                         n_read = read (fd, buf, BUFSIZE);
 243
 244                                         if (n_read < 0) {
 245                                                 perror ("read error");
 246                                                 goto close_fd;
 247                                         }
 248                                         else if (n_read > 0) {
 249                                                 char line[BUFSIZE];
 250                                                 unsigned char c;
 251                                                 int pri = (LOG_USER | LOG_NOTICE);
 252
 253                                                 memset (line, 0, sizeof(line));
 254                                                 p = buf;
 255                                                 q = line;
 256                                                 while (p && (c = *p) && q < &line[sizeof(line) - 1]) {
 257                                                         if (c == '<') {
 258                                                                 /* Parse the magic priority number */
 259                                                                 pri = 0;
 260                                                                 while (isdigit(*(++p))) {
 261                                                                         pri = 10 * pri + (*p - '0');
 262                                                                 }
 263                                                                 if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 264                                                                         pri = (LOG_USER | LOG_NOTICE);
 265                                                         } else if (c == '\n') {
 266                                                                 *q++ = ' ';
 267                                                         } else if (iscntrl(c) && (c < 0177)) {
 268                                                                 *q++ = '^';
 269                                                                 *q++ = c ^ 0100;
 270                                                         } else {
 271                                                                 *q++ = c;
 272                                                         }
 273                                                         p++;
 274                                                 }
 275                                                 *q = '\0';
 276
 277                                                 /* Now log it */
 278                                                 logMessage(pri, line);
 279
 280                                         close_fd:
 281                                                 close (fd);
 282                                                 FD_CLR (fd, &readfds);
 283                                         }
 284                                         else {          /* EOF */
 285                                                 goto close_fd;
 286                                         }
 287                                 }
 288                         }
 289                 }
 290         }
 291 }
 292
 293 #ifdef BB_KLOGD
 294
 295 static void klogd_signal(int sig)
 296 {
 297         ksyslog(7, NULL, 0);
 298         ksyslog(0, 0, 0);
 299         logMessage(0, "Kernel log daemon exiting.");
 300         exit(TRUE);
 301 }
 302
 303 static void doKlogd (void) __attribute__ ((noreturn));
 304 static void doKlogd (void)
 305 {
 306         int priority = LOG_INFO;
 307         char log_buffer[4096];
 308         char *logp;
 309
 310         /* Set up sig handlers */
 311         signal(SIGINT, klogd_signal);
 312         signal(SIGKILL, klogd_signal);
 313         signal(SIGTERM, klogd_signal);
 314         signal(SIGHUP, SIG_IGN);
 315         logMessage(0, "klogd started: "
 316                            "BusyBox v" BB_VER " (" BB_BT ")");
 317
 318         ksyslog(1, NULL, 0);
 319
 320         while (1) {
 321                 /* Use kernel syscalls */
 322                 memset(log_buffer, '\0', sizeof(log_buffer));
 323                 if (ksyslog(2, log_buffer, sizeof(log_buffer)) < 0) {
 324                         char message[80];
 325
 326                         if (errno == EINTR)
 327                                 continue;
 328                         snprintf(message, 79, "klogd: Error return from sys_sycall: " \
 329                                          "%d - %s.\n", errno, strerror(errno));
 330                         logMessage(LOG_SYSLOG | LOG_ERR, message);
 331                         exit(1);
 332                 }
 333                 logp = log_buffer;
 334                 if (*log_buffer == '<') {
 335                         switch (*(log_buffer + 1)) {
 336                         case '0':
 337                                 priority = LOG_EMERG;
 338                                 break;
 339                         case '1':
 340                                 priority = LOG_ALERT;
 341                                 break;
 342                         case '2':
 343                                 priority = LOG_CRIT;
 344                                 break;
 345                         case '3':
 346                                 priority = LOG_ERR;
 347                                 break;
 348                         case '4':
 349                                 priority = LOG_WARNING;
 350                                 break;
 351                         case '5':
 352                                 priority = LOG_NOTICE;
 353                                 break;
 354                         case '6':
 355                                 priority = LOG_INFO;
 356                                 break;
 357                         case '7':
 358                         default:
 359                                 priority = LOG_DEBUG;
 360                         }
 361                         logp += 3;
 362                 }
 363                 logMessage(LOG_KERN | priority, logp);
 364         }
 365
 366 }
 367
 368 #endif
 369
 370 static void daemon_init (char **argv, char *dz, void fn (void)) __attribute__ ((noreturn));
 371 static void daemon_init (char **argv, char *dz, void fn (void))
 372 {
 373         setsid();
 374         chdir ("/");
 375         strncpy(argv[0], dz, strlen(argv[0]));
 376         fn();
 377         exit(0);
 378 }
 379
 380 extern int syslogd_main(int argc, char **argv)
 381 {
 382         int pid, klogd_pid;
 383         int doFork = TRUE;
 384
 385 #ifdef BB_KLOGD
 386         int startKlogd = TRUE;
 387 #endif
 388         int stopDoingThat = FALSE;
 389         char *p;
 390         char **argv1 = argv;
 391
 392         while (--argc > 0 && **(++argv1) == '-') {
 393                 stopDoingThat = FALSE;
 394                 while (stopDoingThat == FALSE && *(++(*argv1))) {
 395                         switch (**argv1) {
 396                         case 'm':
 397                                 if (--argc == 0) {
 398                                         usage(syslogd_usage);
 399                                 }
 400                                 MarkInterval = atoi(*(++argv1)) * 60;
 401                                 break;
 402                         case 'n':
 403                                 doFork = FALSE;
 404                                 break;
 405 #ifdef BB_KLOGD
 406                         case 'K':
 407                                 startKlogd = FALSE;
 408                                 break;
 409 #endif
 410                         case 'O':
 411                                 if (--argc == 0) {
 412                                         usage(syslogd_usage);
 413                                 }
 414                                 logFilePath = *(++argv1);
 415                                 stopDoingThat = TRUE;
 416                                 break;
 417                         default:
 418                                 usage(syslogd_usage);
 419                         }
 420                 }
 421         }
 422
 423         /* Store away localhost's name before the fork */
 424         gethostname(LocalHostName, sizeof(LocalHostName));
 425         if ((p = strchr(LocalHostName, '.'))) {
 426                 *p++ = '\0';
 427         }
 428
 429         umask(0);
 430
 431 #ifdef BB_KLOGD
 432         /* Start up the klogd process */
 433         if (startKlogd == TRUE) {
 434                 klogd_pid = fork();
 435                 if (klogd_pid == 0) {
 436                         daemon_init (argv, "klogd", doKlogd);
 437                 }
 438         }
 439 #endif
 440
 441         if (doFork == TRUE) {
 442                 pid = fork();
 443                 if (pid < 0)
 444                         exit(pid);
 445                 else if (pid == 0) {
 446                         daemon_init (argv, "syslogd", doSyslogd);
 447                 }
 448         } else {
 449                 doSyslogd();
 450         }
 451
 452         exit(TRUE);
 453 }
 454
 455 /*
 456  * Local Variables
 457  * c-file-style: "linux"
 458  * c-basic-offset: 4
 459  * tab-width: 4
 460  * End:
 461  */