+ /* klogd_open() before openlog(), since it might use fixed fd 3,
+ * and openlog() also may use the same fd 3 if we swap them:
+ */
+ klogd_open();
+ openlog("kernel", 0, LOG_KERN);
+ /*
+ * glibc problem: for some reason, glibc changes LOG_KERN to LOG_USER
+ * above. The logic behind this is that standard
+ * http://pubs.opengroup.org/onlinepubs/9699919799/functions/syslog.html
+ * says the following about openlog and syslog:
+ * "LOG_USER
+ * Messages generated by arbitrary processes.
+ * This is the default facility identifier if none is specified."
+ *
+ * I believe glibc misinterpreted this text as "if openlog's
+ * third parameter is 0 (=LOG_KERN), treat it as LOG_USER".
+ * Whereas it was meant to say "if *syslog* is called with facility
+ * 0 in its 1st parameter without prior call to openlog, then perform
+ * implicit openlog(LOG_USER)".
+ *
+ * As a result of this, eh, feature, standard klogd was forced
+ * to open-code its own openlog and syslog implementation (!).
+ *
+ * Note that prohibiting openlog(LOG_KERN) on libc level does not
+ * add any security: any process can open a socket to "/dev/log"
+ * and write a string "<0>Voila, a LOG_KERN + LOG_EMERG message"
+ *
+ * Google code search tells me there is no widespread use of
+ * openlog("foo", 0, 0), thus fixing glibc won't break userspace.
+ *
+ * The bug against glibc was filed:
+ * bugzilla.redhat.com/show_bug.cgi?id=547000
+ */
+
+ if (i)
+ klogd_setloglevel(i);
+
+ signal(SIGHUP, SIG_IGN);
+ /* We want klogd_read to not be restarted, thus _norestart: */
+ bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);
+
+ syslog(LOG_NOTICE, "klogd started: %s", bb_banner);
+
+ write_pidfile(CONFIG_PID_FILE_PATH "/klogd.pid");
+
+ used = 0;
+ while (!bb_got_signal) {
+ int n;
+ int priority;
+ char *start;
+
+ /* "2 -- Read from the log." */
+ start = log_buffer + used;
+ n = klogd_read(start, KLOGD_LOGBUF_SIZE-1 - used);
+ if (n < 0) {
+ if (errno == EINTR)
+ continue;
+ bb_perror_msg(READ_ERROR);
+ break;
+ }
+ start[n] = '\0';
+
+ /* Process each newline-terminated line in the buffer */
+ start = log_buffer;
+ while (1) {
+ char *newline = strchrnul(start, '\n');
+
+ if (*newline == '\0') {
+ /* This line is incomplete */
+
+ /* move it to the front of the buffer */
+ overlapping_strcpy(log_buffer, start);
+ used = newline - start;
+ if (used < KLOGD_LOGBUF_SIZE-1) {
+ /* buffer isn't full */
+ break;
+ }
+ /* buffer is full, log it anyway */
+ used = 0;
+ newline = NULL;
+ } else {
+ *newline++ = '\0';
+ }
+
+ /* Extract the priority */
+ priority = LOG_INFO;
+ if (*start == '<') {
+ start++;
+ if (*start)
+ priority = strtoul(start, &start, 10);
+ if (*start == '>')
+ start++;
+ }
+ /* Log (only non-empty lines) */
+ if (*start)
+ syslog(priority, "%s", start);
+
+ if (!newline)
+ break;
+ start = newline;
+ }
+ }
+
+ klogd_close();
+ syslog(LOG_NOTICE, "klogd: exiting");
+ remove_pidfile(CONFIG_PID_FILE_PATH "/klogd.pid");
+ if (bb_got_signal)
+ kill_myself_with_sig(bb_got_signal);
+ return EXIT_FAILURE;
+}