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klogctl: fix a problem where we don't terminate read data with '\0'

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and then misinterpret it. Code shrink while at it.

function                                             old     new   delta
klogd_main                                           404     362     -42
This commit is contained in:
Denis Vlasenko 2008-11-19 07:59:49 +00:00
parent a09a42cd83
commit 2e7dc5d37b
1 changed files with 17 additions and 20 deletions
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37
sysklogd/klogd.c
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@ -42,14 +42,14 @@ int klogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int klogd_main(int argc UNUSED_PARAM, char **argv) int klogd_main(int argc UNUSED_PARAM, char **argv)
{ {
int i = 0; int i = 0;
char *start; char *opt_c;
int opt; int opt;
int used = 0; int used = 0;
opt = getopt32(argv, "c:n", &start); opt = getopt32(argv, "c:n", &opt_c);
if (opt & OPT_LEVEL) { if (opt & OPT_LEVEL) {
/* Valid levels are between 1 and 8 */ /* Valid levels are between 1 and 8 */
i = xatou_range(start, 1, 8); i = xatou_range(opt_c, 1, 8);
} }
if (!(opt & OPT_FOREGROUND)) { if (!(opt & OPT_FOREGROUND)) {
bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv); bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
@ -57,10 +57,7 @@ int klogd_main(int argc UNUSED_PARAM, char **argv)
openlog("kernel", 0, LOG_KERN); openlog("kernel", 0, LOG_KERN);
bb_signals(0 bb_signals(BB_FATAL_SIGS, klogd_signal);
+ (1 << SIGINT)
+ (1 << SIGTERM)
, klogd_signal);
signal(SIGHUP, SIG_IGN); signal(SIGHUP, SIG_IGN);
/* "Open the log. Currently a NOP" */ /* "Open the log. Currently a NOP" */
@ -73,15 +70,14 @@ int klogd_main(int argc UNUSED_PARAM, char **argv)
syslog(LOG_NOTICE, "klogd started: %s", bb_banner); 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) { while (1) {
int n; int n;
int priority; int priority;
char *start;
/* "2 -- Read from the log." */ /* "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 (n < 0) {
if (errno == EINTR) if (errno == EINTR)
continue; continue;
@ -89,25 +85,25 @@ int klogd_main(int argc UNUSED_PARAM, char **argv)
errno); errno);
break; break;
} }
start[n] = '\0';
/* klogctl buffer parsing modelled after code in dmesg.c */ /* klogctl buffer parsing modelled after code in dmesg.c */
start = &log_buffer[0];
/* Process each newline-terminated line in the buffer */ /* Process each newline-terminated line in the buffer */
while (1) { while (1) {
char *newline = strchr(start, '\n'); char *newline = strchrnul(start, '\n');
if (!newline) { if (*newline == '\0') {
/* This line is incomplete... */ /* This line is incomplete... */
if (start != log_buffer) { if (start != log_buffer) {
/* move it to the front of the 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 */ /* don't log it yet */
used = strlen(log_buffer);
break; break;
} }
/* ...but buffer is full, so log it anyway */ /* ...but if buffer is full, log it anyway */
used = 0; used = 0;
newline = NULL;
} else { } else {
*newline++ = '\0'; *newline++ = '\0';
} }
@ -121,12 +117,13 @@ int klogd_main(int argc UNUSED_PARAM, char **argv)
priority = (*start - '0'); priority = (*start - '0');
start++; start++;
} }
if (*start == '>') { if (*start == '>')
start++; start++;
} }
} /* Log (only non-empty lines) */
if (*start) if (*start)
syslog(priority, "%s", start); syslog(priority, "%s", start);
if (!newline) if (!newline)
break; break;
start = newline; start = newline;