klogd: do not log partial lines

function                                             old     new   delta
overlapping_strcpy                                    15      18      +3
klogd_main                                           438     436      -2

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 18 insertions, 12 deletions

diff --git a/libbb/safe_strncpy.c b/libbb/safe_strncpy.c
index 8eb6a014f..5eb0db0bd 100644
--- a/libbb/safe_strncpy.c
+++ b/libbb/safe_strncpy.c
@@ -20,8 +20,13 @@ char* FAST_FUNC safe_strncpy(char *dst, const char *src, size_t size)
 /* Like strcpy but can copy overlapping strings. */
 void FAST_FUNC overlapping_strcpy(char *dst, const char *src)
 {
-        while ((*dst = *src) != '\0') {
-                dst++;
-                src++;
+        /* Cheap optimization for dst == src case -
+         * better to have it here than in many callers.
+         */
+        if (dst != src) {
+                while ((*dst = *src) != '\0') {
+                        dst++;
+                        src++;
+                }
         }
 }
diff --git a/sysklogd/klogd.c b/sysklogd/klogd.c
index 6766b649d..0d4c2578d 100644
--- a/sysklogd/klogd.c
+++ b/sysklogd/klogd.c
@@ -132,7 +132,7 @@ int klogd_main(int argc UNUSED_PARAM, char **argv)
         int i = 0;
         char *opt_c;
         int opt;
-        int used = 0;
+        int used;
 
         opt = getopt32(argv, "c:n", &opt_c);
         if (opt & OPT_LEVEL) {
@@ -159,6 +159,7 @@ int klogd_main(int argc UNUSED_PARAM, char **argv)
 
         syslog(LOG_NOTICE, "klogd started: %s", bb_banner);
 
+        used = 0;
         while (!bb_got_signal) {
                 int n;
                 int priority;
@@ -175,22 +176,22 @@ int klogd_main(int argc UNUSED_PARAM, char **argv)
                 }
                 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 */
+                                /* 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;
                                 }
-                                /* ...but if buffer is full, log it anyway */
+                                /* buffer is full, log it anyway */
                                 used = 0;
                                 newline = NULL;
                         } else {