sysklogd/klogd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini klogd implementation for busybox
   4  *
   5  * Copyright (C) 2001 by Gennady Feldman <gfeldman@gena01.com>.
   6  * Changes: Made this a standalone busybox module which uses standalone
   7  *                                      syslog() client interface.
   8  *
   9  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  10  *
  11  * Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
  12  *
  13  * "circular buffer" Copyright (C) 2000 by Gennady Feldman <gfeldman@gena01.com>
  14  *
  15  * Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
  16  *
  17  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  18  */
  19
  20 #include "busybox.h"
  21 #include <sys/syslog.h>
  22 #include <sys/klog.h>
  23
  24 static void klogd_signal(int sig ATTRIBUTE_UNUSED)
  25 {
  26         klogctl(7, NULL, 0);
  27         klogctl(0, 0, 0);
  28         syslog(LOG_NOTICE, "Kernel log daemon exiting");
  29         exit(EXIT_SUCCESS);
  30 }
  31
  32 #define OPT_LEVEL        1
  33 #define OPT_FOREGROUND   2
  34
  35 #define KLOGD_LOGBUF_SIZE 4096
  36
  37 int klogd_main(int argc, char **argv);
  38 int klogd_main(int argc, char **argv)
  39 {
  40         RESERVE_CONFIG_BUFFER(log_buffer, KLOGD_LOGBUF_SIZE);
  41         int i = i; /* silence gcc */
  42         char *start;
  43
  44         /* do normal option parsing */
  45         getopt32(argc, argv, "c:n", &start);
  46
  47         if (option_mask32 & OPT_LEVEL) {
  48                 /* Valid levels are between 1 and 8 */
  49                 i = xatoul_range(start, 1, 8);
  50         }
  51
  52         if (!(option_mask32 & OPT_FOREGROUND)) {
  53 #ifdef BB_NOMMU
  54                 vfork_daemon_rexec(0, 1, argc, argv, "-n");
  55 #else
  56                 xdaemon(0, 1);
  57 #endif
  58         }
  59
  60         openlog("kernel", 0, LOG_KERN);
  61
  62         /* Set up sig handlers */
  63         signal(SIGINT, klogd_signal);
  64         signal(SIGKILL, klogd_signal);
  65         signal(SIGTERM, klogd_signal);
  66         signal(SIGHUP, SIG_IGN);
  67
  68         /* "Open the log. Currently a NOP." */
  69         klogctl(1, NULL, 0);
  70
  71         /* Set level of kernel console messaging.. */
  72         if (option_mask32 & OPT_LEVEL)
  73                 klogctl(8, NULL, i);
  74
  75         syslog(LOG_NOTICE, "klogd started: %s", BB_BANNER);
  76
  77         while (1) {
  78                 int n;
  79                 int priority;
  80                 char lastc;
  81
  82                 /* Use kernel syscalls */
  83                 memset(log_buffer, '\0', KLOGD_LOGBUF_SIZE);
  84                 /* It will be null-terminted */
  85                 n = klogctl(2, log_buffer, KLOGD_LOGBUF_SIZE - 1);
  86                 if (n < 0) {
  87                         if (errno == EINTR)
  88                                 continue;
  89                         syslog(LOG_ERR, "klogd: error from klogctl(2): %d - %m",
  90                                    errno);
  91                         break;
  92                 }
  93
  94                 /* klogctl buffer parsing modelled after code in dmesg.c */
  95                 start = &log_buffer[0];
  96                 lastc = '\0';
  97                 priority = LOG_INFO;
  98                 for (i = 0; i < n; i++) {
  99                         if (lastc == '\0' && log_buffer[i] == '<') {
 100                                 i++;
 101                                 // kernel never ganerates multi-digit prios
 102                                 //priority = 0;
 103                                 //while (log_buffer[i] >= '0' && log_buffer[i] <= '9') {
 104                                 //      priority = priority * 10 + (log_buffer[i] - '0');
 105                                 //      i++;
 106                                 //}
 107                                 if (isdigit(log_buffer[i])) {
 108                                         priority = (log_buffer[i] - '0');
 109                                         i++;
 110                                 }
 111                                 if (log_buffer[i] == '>')
 112                                         i++;
 113                                 start = &log_buffer[i];
 114                         }
 115                         if (log_buffer[i] == '\n') {
 116                                 log_buffer[i] = '\0';   /* zero terminate this message */
 117                                 syslog(priority, "%s", start);
 118                                 start = &log_buffer[i + 1];
 119                                 priority = LOG_INFO;
 120                         }
 121                         lastc = log_buffer[i];
 122                 }
 123         }
 124         if (ENABLE_FEATURE_CLEAN_UP)
 125                 RELEASE_CONFIG_BUFFER(log_buffer);
 126
 127         return EXIT_FAILURE;
 128 }