klogd: code de-obfuscation with small code size reduction

2 files changed, 21 insertions, 25 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 077b65840..024d960bf 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -271,6 +271,7 @@ extern void xdaemon(int nochdir, int noclose);
 /* More clever/thorough xdaemon */
 extern void bb_sanitize_stdio_maybe_daemonize(int daemonize);
 extern void bb_sanitize_stdio(void);
+/* NB: be careful: dont open syslog/network sockets before bb_daemonize */
 extern void bb_daemonize(void);
 extern void xchdir(const char *path);
 extern void xsetenv(const char *key, const char *value);
diff --git a/sysklogd/klogd.c b/sysklogd/klogd.c
index 47c2c7252..cca6f5671 100644
--- a/sysklogd/klogd.c
+++ b/sysklogd/klogd.c
@@ -32,12 +32,12 @@ static void klogd_signal(int sig ATTRIBUTE_UNUSED)
 #define OPT_LEVEL        1
 #define OPT_FOREGROUND   2
 
-#define KLOGD_LOGBUF_SIZE 4096
+#define KLOGD_LOGBUF_SIZE BUFSIZ
+#define log_buffer bb_common_bufsiz1
 
 int klogd_main(int argc, char **argv);
 int klogd_main(int argc, char **argv)
 {
-        RESERVE_CONFIG_BUFFER(log_buffer, KLOGD_LOGBUF_SIZE);
         int i = i; /* silence gcc */
         char *start;
 
@@ -53,7 +53,7 @@ int klogd_main(int argc, char **argv)
 #ifdef BB_NOMMU
                 vfork_daemon_rexec(0, 1, argc, argv, "-n");
 #else
-                xdaemon(0, 1);
+                bb_daemonize();
 #endif
         }
 
@@ -68,35 +68,34 @@ int klogd_main(int argc, char **argv)
         /* "Open the log. Currently a NOP." */
         klogctl(1, NULL, 0);
 
-        /* Set level of kernel console messaging.. */
+        /* 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) {
                 int n;
                 int priority;
-                char lastc;
 
-                /* Use kernel syscalls */
-                memset(log_buffer, '\0', KLOGD_LOGBUF_SIZE);
-                /* It will be null-terminted */
                 n = klogctl(2, log_buffer, KLOGD_LOGBUF_SIZE - 1);
                 if (n < 0) {
                         if (errno == EINTR)
                                 continue;
                         syslog(LOG_ERR, "klogd: error from klogctl(2): %d - %m",
-                                   errno);
+                                        errno);
                         break;
                 }
-
-                /* klogctl buffer parsing modelled after code in dmesg.c */
-                start = &log_buffer[0];
-                lastc = '\0';
-                priority = LOG_INFO;
-                for (i = 0; i < n; i++) {
-                        if (lastc == '\0' && log_buffer[i] == '<') {
+                log_buffer[n] = '\n';
+                i = 0;
+                while (i < n) {
+                        priority = LOG_INFO;
+                        start = &log_buffer[i];
+                        if (log_buffer[i] == '<') {
                                 i++;
                                 // kernel never ganerates multi-digit prios
                                 //priority = 0;
@@ -112,17 +111,13 @@ int klogd_main(int argc, char **argv)
                                         i++;
                                 start = &log_buffer[i];
                         }
-                        if (log_buffer[i] == '\n') {
-                                log_buffer[i] = '\0';   /* zero terminate this message */
-                                syslog(priority, "%s", start);
-                                start = &log_buffer[i + 1];
-                                priority = LOG_INFO;
-                        }
-                        lastc = log_buffer[i];
+                        while (log_buffer[i] != '\n')
+                                i++;
+                        log_buffer[i] = '\0';
+                        syslog(priority, "%s", start);
+                        i++;
                 }
         }
-        if (ENABLE_FEATURE_CLEAN_UP)
-                RELEASE_CONFIG_BUFFER(log_buffer);
 
         return EXIT_FAILURE;
 }