klogctl: fix a problem where we don't terminate read data with '\0'
and then misinterpret it. Code shrink while at it.
function old new delta
klogd_main 404 362 -42
diff --git a/sysklogd/klogd.c b/sysklogd/klogd.c
index 723ca80..a0e0bf7 100644
--- a/sysklogd/klogd.c
+++ b/sysklogd/klogd.c
@@ -42,14 +42,14 @@
int klogd_main(int argc UNUSED_PARAM, char **argv)
{
int i = 0;
- char *start;
+ char *opt_c;
int opt;
int used = 0;
- opt = getopt32(argv, "c:n", &start);
+ opt = getopt32(argv, "c:n", &opt_c);
if (opt & OPT_LEVEL) {
/* Valid levels are between 1 and 8 */
- i = xatou_range(start, 1, 8);
+ i = xatou_range(opt_c, 1, 8);
}
if (!(opt & OPT_FOREGROUND)) {
bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
@@ -57,10 +57,7 @@
openlog("kernel", 0, LOG_KERN);
- 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" */
@@ -73,15 +70,14 @@
syslog(LOG_NOTICE, "klogd started: %s", bb_banner);
- /* 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;
+ char *start;
/* "2 -- Read from the log." */
- n = klogctl(2, log_buffer + used, KLOGD_LOGBUF_SIZE-1 - used);
+ start = log_buffer + used;
+ n = klogctl(2, start, KLOGD_LOGBUF_SIZE-1 - used);
if (n < 0) {
if (errno == EINTR)
continue;
@@ -89,25 +85,25 @@
errno);
break;
}
+ start[n] = '\0';
/* 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');
+ char *newline = strchrnul(start, '\n');
- if (!newline) {
+ if (*newline == '\0') {
/* This line is incomplete... */
if (start != log_buffer) {
/* move it to the front of the buffer */
- strcpy(log_buffer, start);
+ overlapping_strcpy(log_buffer, start);
+ used = newline - start;
/* don't log it yet */
- used = strlen(log_buffer);
break;
}
- /* ...but buffer is full, so log it anyway */
+ /* ...but if buffer is full, log it anyway */
used = 0;
+ newline = NULL;
} else {
*newline++ = '\0';
}
@@ -121,12 +117,13 @@
priority = (*start - '0');
start++;
}
- if (*start == '>') {
+ if (*start == '>')
start++;
- }
}
+ /* Log (only non-empty lines) */
if (*start)
syslog(priority, "%s", start);
+
if (!newline)
break;
start = newline;