On Thursday 02 October 2008 03:16:42 am Steve Bennett wrote:
> klogd.c says:
>
> > - /* 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 */
>
> This is particularly noticeable at startup where there are many
> initial messages and lots of them are split.
>
> The attached patch fixes this at the cost of a few bytes.
>
> function old new delta
> klogd_main 362 406 +44
> ------------------------------------------------------------------------------
> (add/remove: 0/0 grow/shrink: 1/0 up/down: 44/0) Total:
> 44 bytes
>
> Please consider applying.
n = klogctl(2, log_buffer + used, KLOGD_LOGBUF_SIZE - used - 1);
if (n < 0) { ...
break;
}
/* klogctl buffer parsing modelled after code in dmesg.c */
start = &log_buffer[0];
/* Process each newline-terminated line in the buffer */
while (1) {
char *newline = memchr(start, '\n', n);
Bug. n is wrong, you have to adjust it (for example, by n += used).
if (*start) {
syslog(priority, "%s", start);
You output the string starting from start...
}
if (newline) {
start = newline;
}
else {
if (start != log_buffer) {
/* This line is incomplete, so move it
to the front of the buffer */
memmove(log_buffer, start, n);
used = n;
}
break;
...but you do not discard it, you move it to the beginning
of the buffer. This will print incomplete line again
on next iteration.
Please test this one.
--
vda
diff -d -urpN busybox.8/sysklogd/klogd.c busybox.9/sysklogd/klogd.c
--- busybox.8/sysklogd/klogd.c 2008-09-28 17:02:08.000000000 +0200
+++ busybox.9/sysklogd/klogd.c 2008-10-04 17:11:44.000000000 +0200
@@ -44,6 +44,8 @@ int klogd_main(int argc UNUSED_PARAM, ch
int i = 0;
char *start;
int opt;
+ int priority;
+ int used = 0;
opt = getopt32(argv, "c:n", &start);
if (opt & OPT_LEVEL) {
@@ -72,16 +74,14 @@ int klogd_main(int argc UNUSED_PARAM, ch
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 */
+ /* Initially null terminate the buffer in case of a very long line */
+ log_buffer[KLOGD_LOGBUF_SIZE - 1] = '\0';
+
while (1) {
int n;
- int priority;
/* "2 -- Read from the log." */
- n = klogctl(2, log_buffer, KLOGD_LOGBUF_SIZE - 1);
+ n = klogctl(2, log_buffer + used, KLOGD_LOGBUF_SIZE-1 - used);
if (n < 0) {
if (errno == EINTR)
continue;
@@ -89,32 +89,47 @@ int klogd_main(int argc UNUSED_PARAM, ch
errno);
break;
}
- log_buffer[n] = '\n';
- i = 0;
- while (i < n) {
+
+ /* klogctl buffer parsing modelled after code in dmesg.c */
+ start = &log_buffer[0];
+
+ /* Process each newline-terminated line in the buffer */
+ while (1) {
+ char *newline = strchr(start, '\n');
+
+ if (!newline) {
+ /* This line is incomplete... */
+ if (start != log_buffer) {
+ /* move it to the front of the buffer */
+ strcpy(log_buffer, start);
+ /* don't log it yet */
+ used = strlen(log_buffer);
+ break;
+ }
+ /* ...but buffer is full, so log it anyway */
+ used = 0;
+ } 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 (*start == '>') {
+ start++;
}
- if (log_buffer[i] == '>')
- i++;
- start = &log_buffer[i];
}
- while (log_buffer[i] != '\n')
- i++;
- log_buffer[i] = '\0';
- syslog(priority, "%s", start);
- i++;
+ if (*start)
+ syslog(priority, "%s", start);
+ if (!newline)
+ break;
+ start = newline;
}
}
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