syslogd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini syslogd implementation for busybox
   4  *
   5  * Copyright (C) 1999,2000 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 #include <limits.h>
  41
  42 #define ksyslog klogctl
  43 extern int ksyslog(int type, char *buf, int len);
  44
  45
  46 /* SYSLOG_NAMES defined to pull some extra junk from syslog.h */
  47 #define SYSLOG_NAMES
  48 #include <sys/syslog.h>
  49
  50 /* Path for the file where all log messages are written */
  51 #define __LOG_FILE "/var/log/messages"
  52
  53 /* Path to the unix socket */
  54 char lfile[PATH_MAX] = "";
  55
  56 static char *logFilePath = __LOG_FILE;
  57
  58 /* interval between marks in seconds */
  59 static int MarkInterval = 20 * 60;
  60
  61 /* localhost's name */
  62 static char LocalHostName[32];
  63
  64 static const char syslogd_usage[] =
  65         "syslogd [OPTION]...\n\n"
  66         "Linux system and kernel (provides klogd) logging utility.\n"
  67         "Note that this version of syslogd/klogd ignores /etc/syslog.conf.\n\n"
  68         "Options:\n"
  69         "\t-m\tChange the mark timestamp interval. default=20min. 0=off\n"
  70         "\t-n\tDo not fork into the background (for when run by init)\n"
  71 #ifdef BB_KLOGD
  72         "\t-K\tDo not start up the klogd process (by default syslogd spawns klogd).\n"
  73 #endif
  74         "\t-O\tSpecify an alternate log file.  default=/var/log/messages\n";
  75
  76 /* Note: There is also a function called "message()" in init.c */
  77 /* Print a message to the log file. */
  78 static void message(char *fmt, ...)
  79                    __attribute__ ((format (printf, 1, 2)));
  80 static void message(char *fmt, ...)
  81 {
  82         int fd;
  83         va_list arguments;
  84
  85         if (
  86                 (fd =
  87                  device_open(logFilePath,
  88                                          O_WRONLY | O_CREAT | O_NOCTTY | O_APPEND |
  89                                          O_NONBLOCK)) >= 0) {
  90                 va_start(arguments, fmt);
  91                 vdprintf(fd, fmt, arguments);
  92                 va_end(arguments);
  93                 close(fd);
  94         } else {
  95                 /* Always send console messages to /dev/console so people will see them. */
  96                 if (
  97                         (fd =
  98                          device_open(_PATH_CONSOLE,
  99                                                  O_WRONLY | O_NOCTTY | O_NONBLOCK)) >= 0) {
 100                         va_start(arguments, fmt);
 101                         vdprintf(fd, fmt, arguments);
 102                         va_end(arguments);
 103                         close(fd);
 104                 } else {
 105                         fprintf(stderr, "Bummer, can't print: ");
 106                         va_start(arguments, fmt);
 107                         vfprintf(stderr, fmt, arguments);
 108                         fflush(stderr);
 109                         va_end(arguments);
 110                 }
 111         }
 112 }
 113
 114 static void logMessage(int pri, char *msg)
 115 {
 116         time_t now;
 117         char *timestamp;
 118         static char res[20] = "";
 119         CODE *c_pri, *c_fac;
 120
 121         if (pri != 0) {
 122                 for (c_fac = facilitynames;
 123                          c_fac->c_name && !(c_fac->c_val == LOG_FAC(pri) << 3); c_fac++);
 124                 for (c_pri = prioritynames;
 125                          c_pri->c_name && !(c_pri->c_val == LOG_PRI(pri)); c_pri++);
 126                 if (*c_fac->c_name == '\0' || *c_pri->c_name == '\0')
 127                         snprintf(res, sizeof(res), "<%d>", pri);
 128                 else
 129                         snprintf(res, sizeof(res), "%s.%s", c_fac->c_name, c_pri->c_name);
 130         }
 131
 132         if (strlen(msg) < 16 || msg[3] != ' ' || msg[6] != ' ' ||
 133                 msg[9] != ':' || msg[12] != ':' || msg[15] != ' ') {
 134                 time(&now);
 135                 timestamp = ctime(&now) + 4;
 136                 timestamp[15] = '\0';
 137         } else {
 138                 timestamp = msg;
 139                 timestamp[15] = '\0';
 140                 msg += 16;
 141         }
 142
 143         /* todo: supress duplicates */
 144
 145         /* now spew out the message to wherever it is supposed to go */
 146         message("%s %s %s %s\n", timestamp, LocalHostName, res, msg);
 147 }
 148
 149 static void quit_signal(int sig)
 150 {
 151         logMessage(0, "System log daemon exiting.");
 152         unlink(lfile);
 153         exit(TRUE);
 154 }
 155
 156 static void domark(int sig)
 157 {
 158         if (MarkInterval > 0) {
 159                 logMessage(LOG_SYSLOG | LOG_INFO, "-- MARK --");
 160                 alarm(MarkInterval);
 161         }
 162 }
 163
 164 static void doSyslogd (void) __attribute__ ((noreturn));
 165 static void doSyslogd (void)
 166 {
 167         struct sockaddr_un sunx;
 168         size_t addrLength;
 169         int sock_fd;
 170         fd_set readfds;
 171         char lfile[PATH_MAX];
 172         int t = readlink(_PATH_LOG, lfile, sizeof(lfile) - 1); /* Resolve symlinks */
 173
 174         /* Set up sig handlers */
 175         signal (SIGINT,  quit_signal);
 176         signal (SIGTERM, quit_signal);
 177         signal (SIGQUIT, quit_signal);
 178         signal (SIGHUP,  SIG_IGN);
 179         signal (SIGALRM, domark);
 180         alarm (MarkInterval);
 181
 182         if (t == -1)
 183                 strncpy(lfile, _PATH_LOG, sizeof(lfile));
 184         else
 185                 lfile[t] = '\0';
 186
 187         unlink (lfile);
 188
 189         memset (&sunx, 0, sizeof(sunx));
 190
 191         sunx.sun_family = AF_UNIX;
 192         strncpy (sunx.sun_path, lfile, sizeof(sunx.sun_path));
 193         if ((sock_fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 194                 perror ("Couldn't obtain descriptor for socket " _PATH_LOG);
 195                 exit (FALSE);
 196         }
 197
 198         addrLength = sizeof (sunx.sun_family) + strlen (sunx.sun_path);
 199         if ((bind (sock_fd, (struct sockaddr *) &sunx, addrLength)) ||
 200                 (listen (sock_fd, 5))) {
 201                 perror ("Could not connect to socket " _PATH_LOG);
 202                 exit (FALSE);
 203         }
 204
 205         if (chmod (lfile, 0666) < 0) {
 206                 perror ("Could not set permission on " _PATH_LOG);
 207                 exit (FALSE);
 208         }
 209
 210         FD_ZERO (&readfds);
 211         FD_SET (sock_fd, &readfds);
 212
 213         logMessage (0, "syslogd started: BusyBox v" BB_VER " (" BB_BT ")");
 214
 215         for (;;) {
 216                 int n_ready;
 217                 int fd;
 218
 219                 if ((n_ready = select (FD_SETSIZE, &readfds, NULL, NULL, NULL)) < 0) {
 220                         if (errno == EINTR) continue; /* alarm may have happened. */
 221                         perror ("select");
 222                         exit (FALSE);
 223                 }
 224
 225                 /* Skip stdin, stdout, stderr */
 226                 for (fd = 3; fd <= FD_SETSIZE; fd++) {
 227                         if (FD_ISSET (fd, &readfds)) {
 228                                 if (fd == sock_fd) {
 229                                         int conn;
 230                                         if ((conn = accept(sock_fd, (struct sockaddr *) &sunx,
 231                                                                            &addrLength)) < 0) {
 232                                                 perror ("accept");
 233                                                 exit (FALSE); /* #### ??? */
 234                                         }
 235                                         FD_SET (conn, &readfds);
 236                                 }
 237                                 else {
 238 #define                   BUFSIZE 1024 + 1
 239                                         char buf[BUFSIZE];
 240                                         char *q, *p;
 241                                         int n_read;
 242
 243                                         n_read = read (fd, buf, BUFSIZE);
 244
 245                                         if (n_read < 0) {
 246                                                 perror ("read error");
 247                                                 goto close_fd;
 248                                         }
 249                                         else if (n_read > 0) {
 250                                                 char line[BUFSIZE];
 251                                                 unsigned char c;
 252                                                 int pri = (LOG_USER | LOG_NOTICE);
 253
 254                                                 memset (line, 0, sizeof(line));
 255                                                 p = buf;
 256                                                 q = line;
 257                                                 while (p && (c = *p) && q < &line[sizeof(line) - 1]) {
 258                                                         if (c == '<') {
 259                                                                 /* Parse the magic priority number */
 260                                                                 pri = 0;
 261                                                                 while (isdigit(*(++p))) {
 262                                                                         pri = 10 * pri + (*p - '0');
 263                                                                 }
 264                                                                 if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
 265                                                                         pri = (LOG_USER | LOG_NOTICE);
 266                                                         } else if (c == '\n') {
 267                                                                 *q++ = ' ';
 268                                                         } else if (iscntrl(c) && (c < 0177)) {
 269                                                                 *q++ = '^';
 270                                                                 *q++ = c ^ 0100;
 271                                                         } else {
 272                                                                 *q++ = c;
 273                                                         }
 274                                                         p++;
 275                                                 }
 276                                                 *q = '\0';
 277
 278                                                 /* Now log it */
 279                                                 logMessage(pri, line);
 280
 281                                         close_fd:
 282                                                 close (fd);
 283                                                 FD_CLR (fd, &readfds);
 284                                         }
 285                                         else {          /* EOF */
 286                                                 goto close_fd;
 287                                         }
 288                                 }
 289                         }
 290                 }
 291         }
 292 }
 293
 294 #ifdef BB_KLOGD
 295
 296 static void klogd_signal(int sig)
 297 {
 298         ksyslog(7, NULL, 0);
 299         ksyslog(0, 0, 0);
 300         logMessage(0, "Kernel log daemon exiting.");
 301         exit(TRUE);
 302 }
 303
 304 static void doKlogd (void) __attribute__ ((noreturn));
 305 static void doKlogd (void)
 306 {
 307         int priority = LOG_INFO;
 308         char log_buffer[4096];
 309         char *logp;
 310
 311         /* Set up sig handlers */
 312         signal(SIGINT, klogd_signal);
 313         signal(SIGKILL, klogd_signal);
 314         signal(SIGTERM, klogd_signal);
 315         signal(SIGHUP, SIG_IGN);
 316         logMessage(0, "klogd started: "
 317                            "BusyBox v" BB_VER " (" BB_BT ")");
 318
 319         ksyslog(1, NULL, 0);
 320
 321         while (1) {
 322                 /* Use kernel syscalls */
 323                 memset(log_buffer, '\0', sizeof(log_buffer));
 324                 if (ksyslog(2, log_buffer, sizeof(log_buffer)) < 0) {
 325                         char message[80];
 326
 327                         if (errno == EINTR)
 328                                 continue;
 329                         snprintf(message, 79, "klogd: Error return from sys_sycall: " \
 330                                          "%d - %s.\n", errno, strerror(errno));
 331                         logMessage(LOG_SYSLOG | LOG_ERR, message);
 332                         exit(1);
 333                 }
 334                 logp = log_buffer;
 335                 if (*log_buffer == '<') {
 336                         switch (*(log_buffer + 1)) {
 337                         case '0':
 338                                 priority = LOG_EMERG;
 339                                 break;
 340                         case '1':
 341                                 priority = LOG_ALERT;
 342                                 break;
 343                         case '2':
 344                                 priority = LOG_CRIT;
 345                                 break;
 346                         case '3':
 347                                 priority = LOG_ERR;
 348                                 break;
 349                         case '4':
 350                                 priority = LOG_WARNING;
 351                                 break;
 352                         case '5':
 353                                 priority = LOG_NOTICE;
 354                                 break;
 355                         case '6':
 356                                 priority = LOG_INFO;
 357                                 break;
 358                         case '7':
 359                         default:
 360                                 priority = LOG_DEBUG;
 361                         }
 362                         logp += 3;
 363                 }
 364                 logMessage(LOG_KERN | priority, logp);
 365         }
 366
 367 }
 368
 369 #endif
 370
 371 static void daemon_init (char **argv, char *dz, void fn (void)) __attribute__ ((noreturn));
 372 static void daemon_init (char **argv, char *dz, void fn (void))
 373 {
 374         setsid();
 375         chdir ("/");
 376         strncpy(argv[0], dz, strlen(argv[0]));
 377         fn();
 378         exit(0);
 379 }
 380
 381 extern int syslogd_main(int argc, char **argv)
 382 {
 383         int pid, klogd_pid;
 384         int doFork = TRUE;
 385
 386 #ifdef BB_KLOGD
 387         int startKlogd = TRUE;
 388 #endif
 389         int stopDoingThat = FALSE;
 390         char *p;
 391         char **argv1 = argv;
 392
 393         while (--argc > 0 && **(++argv1) == '-') {
 394                 stopDoingThat = FALSE;
 395                 while (stopDoingThat == FALSE && *(++(*argv1))) {
 396                         switch (**argv1) {
 397                         case 'm':
 398                                 if (--argc == 0) {
 399                                         usage(syslogd_usage);
 400                                 }
 401                                 MarkInterval = atoi(*(++argv1)) * 60;
 402                                 break;
 403                         case 'n':
 404                                 doFork = FALSE;
 405                                 break;
 406 #ifdef BB_KLOGD
 407                         case 'K':
 408                                 startKlogd = FALSE;
 409                                 break;
 410 #endif
 411                         case 'O':
 412                                 if (--argc == 0) {
 413                                         usage(syslogd_usage);
 414                                 }
 415                                 logFilePath = *(++argv1);
 416                                 stopDoingThat = TRUE;
 417                                 break;
 418                         default:
 419                                 usage(syslogd_usage);
 420                         }
 421                 }
 422         }
 423
 424         /* Store away localhost's name before the fork */
 425         gethostname(LocalHostName, sizeof(LocalHostName));
 426         if ((p = strchr(LocalHostName, '.'))) {
 427                 *p++ = '\0';
 428         }
 429
 430         umask(0);
 431
 432 #ifdef BB_KLOGD
 433         /* Start up the klogd process */
 434         if (startKlogd == TRUE) {
 435                 klogd_pid = fork();
 436                 if (klogd_pid == 0) {
 437                         daemon_init (argv, "klogd", doKlogd);
 438                 }
 439         }
 440 #endif
 441
 442         if (doFork == TRUE) {
 443                 pid = fork();
 444                 if (pid < 0)
 445                         exit(pid);
 446                 else if (pid == 0) {
 447                         daemon_init (argv, "syslogd", doSyslogd);
 448                 }
 449         } else {
 450                 doSyslogd();
 451         }
 452
 453         exit(TRUE);
 454 }
 455
 456 /*
 457  * Local Variables
 458  * c-file-style: "linux"
 459  * c-basic-offset: 4
 460  * tab-width: 4
 461  * End:
 462  */