Changeset 2725 in MondoRescue for branches/2.2.9/mindi-busybox/sysklogd/klogd.c

Timestamp:

Feb 25, 2011, 9:26:54 PM (13 years ago)

Author:

Bruno Cornec

Message:

• Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3

File:

• branches/2.2.9/mindi-busybox/sysklogd/klogd.c (modified) (2 diffs)

branches/2.2.9/mindi-busybox/sysklogd/klogd.c

@@ -5 +5 @@
  * 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) 1999-2004 by Erik Andersen <andersen@codepoet.org>
@@ -15 +15 @@
  * 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.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
 #include "libbb.h"
-#include <sys/syslog.h>
-#include <sys/klog.h>
-
-static void klogd_signal(int sig ATTRIBUTE_UNUSED)
-{
-    klogctl(7, NULL, 0);
-    klogctl(0, 0, 0);
-    syslog(LOG_NOTICE, "Kernel log daemon exiting");
-    exit(EXIT_SUCCESS);
-}
-
-#define OPT_LEVEL        1
-#define OPT_FOREGROUND   2
-
-#define KLOGD_LOGBUF_SIZE BUFSIZ
+#include <syslog.h>
+
+
+/* The Linux-specific klogctl(3) interface does not rely on the filesystem and
+ * allows us to change the console loglevel. Alternatively, we read the
+ * messages from _PATH_KLOG. */
+
+#if ENABLE_FEATURE_KLOGD_KLOGCTL
+
+# include <sys/klog.h>
+
+static void klogd_open(void)
+{
+    /* "Open the log. Currently a NOP" */
+    klogctl(1, NULL, 0);
+}
+
+static void klogd_setloglevel(int lvl)
+{
+    /* "printk() prints a message on the console only if it has a loglevel
+     * less than console_loglevel". Here we set console_loglevel = lvl. */
+    klogctl(8, NULL, lvl);
+}
+
+static int klogd_read(char *bufp, int len)
+{
+    return klogctl(2, bufp, len);
+}
+# define READ_ERROR "klogctl(2) error"
+
+static void klogd_close(void)
+{
+    /* 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" */
+}
+
+#else
+
+# include <paths.h>
+# ifndef _PATH_KLOG
+#  ifdef __GNU__
+#   define _PATH_KLOG "/dev/klog"
+#  else
+#   error "your system's _PATH_KLOG is unknown"
+#  endif
+# endif
+# define PATH_PRINTK "/proc/sys/kernel/printk"
+
+enum { klogfd = 3 };
+
+static void klogd_open(void)
+{
+    int fd = xopen(_PATH_KLOG, O_RDONLY);
+    xmove_fd(fd, klogfd);
+}
+
+static void klogd_setloglevel(int lvl)
+{
+    FILE *fp = fopen_or_warn(PATH_PRINTK, "w");
+    if (fp) {
+        /* This changes only first value:
+         * "messages with a higher priority than this
+         * [that is, with numerically lower value]
+         * will be printed to the console".
+         * The other three values in this pseudo-file aren't changed.
+         */
+        fprintf(fp, "%u\n", lvl);
+        fclose(fp);
+    }
+}
+
+static int klogd_read(char *bufp, int len)
+{
+    return read(klogfd, bufp, len);
+}
+# define READ_ERROR "read error"
+
+static void klogd_close(void)
+{
+    klogd_setloglevel(7);
+    if (ENABLE_FEATURE_CLEAN_UP)
+        close(klogfd);
+}
+
+#endif
+
 #define log_buffer bb_common_bufsiz1
-
-int klogd_main(int argc, char **argv);
-int klogd_main(int argc, char **argv)
-{
-    int i = i; /* silence gcc */
-    char *start;
-
-    /* do normal option parsing */
-    getopt32(argv, "c:n", &start);
-
-    if (option_mask32 & OPT_LEVEL) {
+enum {
+    KLOGD_LOGBUF_SIZE = sizeof(log_buffer),
+    OPT_LEVEL      = (1 << 0),
+    OPT_FOREGROUND = (1 << 1),
+};
+
+/* TODO: glibc openlog(LOG_KERN) reverts to LOG_USER instead,
+ * because that's how they interpret word "default"
+ * in the openlog() manpage:
+ *      LOG_USER (default)
+ *              generic user-level messages
+ * and the fact that LOG_KERN is a constant 0.
+ * glibc interprets it as "0 in openlog() call means 'use default'".
+ * I think it means "if openlog wasn't called before syslog() is called,
+ * use default".
+ * Convincing glibc maintainers otherwise is, as usual, nearly impossible.
+ * Should we open-code syslog() here to use correct facility?
+ */
+
+int klogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int klogd_main(int argc UNUSED_PARAM, char **argv)
+{
+    int i = 0;
+    char *opt_c;
+    int opt;
+    int used;
+
+    opt = getopt32(argv, "c:n", &opt_c);
+    if (opt & OPT_LEVEL) {
         /* Valid levels are between 1 and 8 */
-        i = xatoul_range(start, 1, 8);
-    }
-
-    if (!(option_mask32 & OPT_FOREGROUND)) {
+        i = xatou_range(opt_c, 1, 8);
+    }
+    if (!(opt & OPT_FOREGROUND)) {
         bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
     }
 
+    logmode = LOGMODE_SYSLOG;
+
+    /* 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);
 
-    /* Set up sig handlers */
-    signal(SIGINT, klogd_signal);
-    signal(SIGKILL, klogd_signal);
-    signal(SIGTERM, klogd_signal);
+    if (i)
+        klogd_setloglevel(i);
+
+    bb_signals(BB_FATAL_SIGS, record_signo);
     signal(SIGHUP, SIG_IGN);
 
-    /* "Open the log. Currently a NOP." */
-    klogctl(1, NULL, 0);
-
-    /* Set level of kernel console messaging. */
-    if (option_mask32 & OPT_LEVEL)
-        klogctl(8, NULL, i);
-
     syslog(LOG_NOTICE, "klogd started: %s", bb_banner);
 
-    /* Note: this code does not detect incomplete messages
-     * (messages not ending with '\n' or just when kernel
-     * generates too many messages for us to keep up)
-     * and will split them in two separate lines */
-    while (1) {
+    used = 0;
+    while (!bb_got_signal) {
         int n;
         int priority;
-
-        n = klogctl(2, log_buffer, KLOGD_LOGBUF_SIZE - 1);
+        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;
-            syslog(LOG_ERR, "klogd: error from klogctl(2): %d - %m",
-                    errno);
+            bb_perror_msg(READ_ERROR);
             break;
         }
-        log_buffer[n] = '\n';
-        i = 0;
-        while (i < n) {
+        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;
-            start = &log_buffer[i];
-            if (log_buffer[i] == '<') {
-                i++;
-                // kernel never ganerates multi-digit prios
-                //priority = 0;
-                //while (log_buffer[i] >= '0' && log_buffer[i] <= '9') {
-                //  priority = priority * 10 + (log_buffer[i] - '0');
-                //  i++;
-                //}
-                if (isdigit(log_buffer[i])) {
-                    priority = (log_buffer[i] - '0');
-                    i++;
+            if (*start == '<') {
+                start++;
+                if (*start) {
+                    /* kernel never generates multi-digit prios */
+                    priority = (*start - '0');
+                    start++;
                 }
-                if (log_buffer[i] == '>')
-                    i++;
-                start = &log_buffer[i];
+                if (*start == '>')
+                    start++;
             }
-            while (log_buffer[i] != '\n')
-                i++;
-            log_buffer[i] = '\0';
-            syslog(priority, "%s", start);
-            i++;
+            /* Log (only non-empty lines) */
+            if (*start)
+                syslog(priority, "%s", start);
+
+            if (!newline)
+                break;
+            start = newline;
         }
     }
 
+    klogd_close();
+    syslog(LOG_NOTICE, "klogd: exiting");
+    if (bb_got_signal)
+        kill_myself_with_sig(bb_got_signal);
     return EXIT_FAILURE;
 }