top: add -m ("memory") option
[oweals/busybox.git] / sysklogd / klogd.c
index d5e330bdf75855098f0db48ff53c3e7ab57ca885..c54e80a3525ca9ad2d91259aa2a79ad71feb6897 100644 (file)
 /*
  * Mini klogd implementation for busybox
  *
- * Copyright (C) 2001 by Gennady Feldman <gfeldman@cachier.com>.
+ * Copyright (C) 2001 by Gennady Feldman <gfeldman@gena01.com>.
  * Changes: Made this a standalone busybox module which uses standalone
- *                                     syslog() client interface.
+ *                                     syslog() client interface.
  *
- * Copyright (C) 1999,2000,2001 by Lineo, inc.
- * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
  * Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
  *
- * "circular buffer" Copyright (C) 2000 by Gennady Feldman <gfeldman@mail.com>
+ * "circular buffer" Copyright (C) 2000 by Gennady Feldman <gfeldman@gena01.com>
  *
- * Maintainer: Gennady Feldman <gena01@cachier.com> as of Mar 12, 2001
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
  *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <signal.h> /* for our signal() handlers */
-#include <string.h> /* strncpy() */
-#include <errno.h>  /* errno and friends */
-#include <unistd.h>
-#include <ctype.h>
-#include <sys/syslog.h>
-
-#if ! defined __GLIBC__ && ! defined __UCLIBC__
-#include <sys/syscall.h>
-#include <linux/unistd.h>
-
-#ifndef __alpha__
-# define __NR_klogctl __NR_syslog
-static inline _syscall3(int, klogctl, int, type, char *, b, int, len);
-#else                                                  /* __alpha__ */
-#define klogctl syslog
-#endif
-
-#else
-# include <sys/klog.h>
-#endif
-#include "busybox.h"
+#include "libbb.h"
+#include <syslog.h>
+#include <sys/klog.h>
 
 static void klogd_signal(int sig)
 {
-       klogctl(7, NULL, 0);
-       klogctl(0, 0, 0);
-       //logMessage(0, "Kernel log daemon exiting.");
-       syslog_msg(LOG_DAEMON, 0, "Kernel log daemon exiting.");
-       exit(TRUE);
+       /* FYI: cmd 7 is equivalent to setting console_loglevel to 7
+        * via klogctl(8, NULL, 7). */
+       klogctl(7, NULL, 0); /* "7 -- Enable printk's to console" */
+       klogctl(0, NULL, 0); /* "0 -- Close the log. Currently a NOP" */
+       syslog(LOG_NOTICE, "klogd: exiting");
+       kill_myself_with_sig(sig);
 }
 
-static void doKlogd (void) __attribute__ ((noreturn));
-static void doKlogd (void)
+#define log_buffer bb_common_bufsiz1
+enum {
+       KLOGD_LOGBUF_SIZE = sizeof(log_buffer),
+       OPT_LEVEL      = (1 << 0),
+       OPT_FOREGROUND = (1 << 1),
+};
+
+int klogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int klogd_main(int argc UNUSED_PARAM, char **argv)
 {
-       int priority = LOG_INFO;
-       char log_buffer[4096];
-       int i, n, lastc;
-       char *start;
-
-       /* Set up sig handlers */
-       signal(SIGINT, klogd_signal);
-       signal(SIGKILL, klogd_signal);
-       signal(SIGTERM, klogd_signal);
+       int i = 0;
+       char *opt_c;
+       int opt;
+       int used = 0;
+
+       opt = getopt32(argv, "c:n", &opt_c);
+       if (opt & OPT_LEVEL) {
+               /* Valid levels are between 1 and 8 */
+               i = xatou_range(opt_c, 1, 8);
+       }
+       if (!(opt & OPT_FOREGROUND)) {
+               bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
+       }
+
+       openlog("kernel", 0, LOG_KERN);
+
+       bb_signals(BB_FATAL_SIGS, klogd_signal);
        signal(SIGHUP, SIG_IGN);
 
-       /* "Open the log. Currently a NOP." */
+       /* "Open the log. Currently a NOP" */
        klogctl(1, NULL, 0);
 
-       syslog_msg(LOG_DAEMON, 0, "klogd started: BusyBox v" BB_VER " (" BB_BT ")");
+       /* "printk() prints a message on the console only if it has a loglevel
+        * less than console_loglevel". Here we set console_loglevel = i. */
+       if (i)
+               klogctl(8, NULL, i);
+
+       syslog(LOG_NOTICE, "klogd started: %s", bb_banner);
 
        while (1) {
-               /* Use kernel syscalls */
-               memset(log_buffer, '\0', sizeof(log_buffer));
-               n = klogctl(2, log_buffer, sizeof(log_buffer));
-               if (n < 0) {
-                       char message[80];
+               int n;
+               int priority;
+               char *start;
 
+               /* "2 -- Read from the log." */
+               start = log_buffer + used;
+               n = klogctl(2, start, KLOGD_LOGBUF_SIZE-1 - used);
+               if (n < 0) {
                        if (errno == EINTR)
                                continue;
-                       snprintf(message, 79, "klogd: Error return from sys_sycall: %d - %s.\n", 
-                                                                                               errno, strerror(errno));
-                       syslog_msg(LOG_DAEMON, LOG_SYSLOG | LOG_ERR, message);
-                       exit(1);
+                       syslog(LOG_ERR, "klogd: error %d in klogctl(2): %m",
+                                       errno);
+                       break;
                }
+               start[n] = '\0';
 
                /* klogctl buffer parsing modelled after code in dmesg.c */
-               start=&log_buffer[0];
-               lastc='\0';
-               for (i=0; i<n; i++) {
-                       if (lastc == '\0' && log_buffer[i] == '<') {
-                               priority = 0;
-                               i++;
-                               while (isdigit(log_buffer[i])) {
-                                       priority = priority*10+(log_buffer[i]-'0');
-                                       i++;
+               /* 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... */
+                               if (start != log_buffer) {
+                                       /* move it to the front of the buffer */
+                                       overlapping_strcpy(log_buffer, start);
+                                       used = newline - start;
+                                       /* don't log it yet */
+                                       break;
                                }
-                               if (log_buffer[i] == '>') i++;
-                               start = &log_buffer[i];
-                       }
-                       if (log_buffer[i] == '\n') {
-                               log_buffer[i] = '\0';  /* zero terminate this message */
-                               syslog_msg(LOG_DAEMON, LOG_KERN | priority, start);
-                               start = &log_buffer[i+1];
-                               priority = LOG_INFO;
+                               /* ...but if buffer is full, log it anyway */
+                               used = 0;
+                               newline = NULL;
+                       } else {
+                               *newline++ = '\0';
                        }
-                       lastc = log_buffer[i];
-               }
-       }
-}
 
-static void daemon_init (char **argv, char *dz, void fn (void))
-{
-       setsid(); /* start a new session? */
-       strncpy(argv[0], dz, strlen(argv[0]));
-       fn();
-       exit(0);
-}
+                       /* Extract the priority */
+                       priority = LOG_INFO;
+                       if (*start == '<') {
+                               start++;
+                               if (*start) {
+                                       /* kernel never generates multi-digit prios */
+                                       priority = (*start - '0');
+                                       start++;
+                               }
+                               if (*start == '>')
+                                       start++;
+                       }
+                       /* Log (only non-empty lines) */
+                       if (*start)
+                               syslog(priority, "%s", start);
 
-extern int klogd_main(int argc, char **argv)
-{
-       /* no options, no getopt */
-       int opt, pid;
-       int doFork = TRUE;
-
-       /* do normal option parsing */
-       while ((opt = getopt(argc, argv, "n")) > 0) {
-               switch (opt) {
-                       case 'n':
-                               doFork = FALSE;
+                       if (!newline)
                                break;
-                       default:
-                               show_usage();
+                       start = newline;
                }
        }
 
-       if (doFork == TRUE) {
-               pid = fork();
-               if (pid < 0)
-                       exit(pid);
-               else if (pid == 0) {
-                       daemon_init (argv, "klogd", doKlogd);
-               }
-       } else {
-               doKlogd();
-       }
-       
-       return EXIT_SUCCESS;
+       return EXIT_FAILURE;
 }
-
-/*
-Local Variables
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/