top: add -m ("memory") option

[oweals/busybox.git] / sysklogd / klogd.c

diff --git a/sysklogd/klogd.c b/sysklogd/klogd.c
index 6a675b8b3fdb5faa5c18e7896de2a26344420652..c54e80a3525ca9ad2d91259aa2a79ad71feb6897 100644 (file)
--- a/sysklogd/klogd.c
+++ b/sysklogd/klogd.c
@@ -21,12 +21,14 @@
 #include <syslog.h>
 #include <sys/klog.h>
 
-static void klogd_signal(int sig ATTRIBUTE_UNUSED)
+static void klogd_signal(int sig)
 {
-       klogctl(7, NULL, 0);
-       klogctl(0, NULL, 0);
+       /* 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");
-       exit(EXIT_SUCCESS);
+       kill_myself_with_sig(sig);
 }
 
 #define log_buffer bb_common_bufsiz1
@@ -37,83 +39,95 @@ enum {
 };
 
 int klogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int klogd_main(int argc, char **argv)
+int klogd_main(int argc UNUSED_PARAM, char **argv)
 {
-       int i = i; /* silence gcc */
-       char *start;
+       int i = 0;
+       char *opt_c;
+       int opt;
+       int used = 0;
 
-       /* do normal option parsing */
-       getopt32(argv, "c:n", &start);
-
-       if (option_mask32 & OPT_LEVEL) {
+       opt = getopt32(argv, "c:n", &opt_c);
+       if (opt & OPT_LEVEL) {
                /* Valid levels are between 1 and 8 */
-               i = xatoul_range(start, 1, 8);
+               i = xatou_range(opt_c, 1, 8);
        }
-
-       if (!(option_mask32 & OPT_FOREGROUND)) {
+       if (!(opt & OPT_FOREGROUND)) {
                bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
        }
 
        openlog("kernel", 0, LOG_KERN);
 
-       /* Set up sig handlers */
-       bb_signals(0
-               + (1 << SIGINT)
-               + (1 << SIGTERM)
-               , klogd_signal);
+       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);
 
-       /* Set level of kernel console messaging. */
-       if (option_mask32 & OPT_LEVEL)
+       /* "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);
 
-       /* 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) {
                int n;
                int priority;
+               char *start;
 
-               n = klogctl(2, log_buffer, KLOGD_LOGBUF_SIZE - 1);
+               /* "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;
-                       syslog(LOG_ERR, "klogd: error from klogctl(2): %d - %m",
+                       syslog(LOG_ERR, "klogd: error %d in klogctl(2): %m",
                                        errno);
                        break;
                }
-               log_buffer[n] = '\n';
-               i = 0;
-               while (i < n) {
+               start[n] = '\0';
+
+               /* klogctl buffer parsing modelled after code in dmesg.c */
+               /* 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;
+                               }
+                               /* ...but if 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;
                }
        }