truncated syslog messages

[Denis Vlasenko]

On Wednesday 21 February 2007 15:24, Stephane Billiart wrote:
> The problem:
> 
> server# logger "message to syslog"
> server# killall syslogd
> server# tail /var/log/messages 
> Feb 21 08:50:19 server syslog.info syslogd started: BusyBox v1.5.0.svn
> Feb 21 08:50:23 server kern.warn kernel: TSC 
> Feb 21 08:50:31 server user.notice root: messa
> Feb 21 08:51:25 server syslog.info syslogd exiting
> server# ls -l /dev/log /var/syslog
> lrwxrwxrwx    1 root     root           11 Jan  4  1980 /dev/log -> /var/syslog=
> srw-rw-rw-    1 root     root            0 Feb 21 08:50 /var/syslog=
> 
> All messages syslog receives are truncated, not the ones it writes itself...
> 
> My embedded system runs linux 2.6.19.2 with uClibc 0.9.27.
> I have mdev activated in busybox, /dev is a ramfs partition and /var is tmpfs.
> I tried with and without CONFIG_FEATURE_IPC_SYSLOG and get the same results

busybox and uclibc .config? syslogd parameters?

> I see the problem with the SVN and 1.4.1 versions but not with 1.2.2.1
> With glibc 2.3.6, everything is fine also.

glibc 2.4 and uclibc x86_64 svn (patched to fix stdio bug) works ok with

syslogd -m 0 -n -S -s 999 -b 9 -O $PWD/syslog

here

> There's been a lot of changes in syslogd recently.
> I started looking at the code but so far did not find anything to explain
> those short reads from /dev/log.

Adding few printf's is probably the fastest method to narrow it down.
Example:


static void log_locally(char *msg)
{
        static time_t last;
        struct flock fl;
        int len = strlen(msg);

+fprintf(stderr, "log_locally: '%s'\n", msg);

#if ENABLE_FEATURE_IPC_SYSLOG
...

static void timestamp_and_log(int pri, char *msg, int len)
{
        char *timestamp;

+fprintf(stderr, "timestamp_and_log: %d '%s'\n", len, msg);

        if (len < 16 || msg[3] != ' ' || msg[6] != ' '
         || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
        ) {
...

static void split_escape_and_log(char *tmpbuf, int len)
{
        char *p = tmpbuf;

+fprintf(stderr, "split_escape_and_log: %d '%s'\n", len, tmpbuf);

        tmpbuf += len;
        while (p < tmpbuf) {


Then killall syslogd, run new one with -n from the console,
and watch debug output.
--
vda