well, I do not buy the idea of security reasons, but I agree with your last
sentence that they do not see the need to make this a configurable option,
the error log does not need it.
regarding my purpose: mod_dumpio dumps data into the error log file in
chunks, I want to merge them if the message is large and do something with
it before logging. With this limitation, I will need to write it to
somewhere else using my custom file handler.
Vu
On Wed, Mar 13, 2013 at 5:46 PM, <r...@seid-online.de> wrote:
> On Wed, Mar 13, 2013 at 04:40:50PM +0100, Hoang-Vu Dang wrote:
> > I traced this into the Apache source code (ver 2.4.4). It looks like the
> > error message string is really limited by the size of 8KB.
> >
> > This line is in server/log.c:1097
> >
> > "
> > static void log_error_core(const char *file, int line, int module_index,
> > int level,
> > apr_status_t status, const server_rec *s,
> > const conn_rec *c,
> > const request_rec *r, apr_pool_t *pool,
> > const char *fmt, va_list args)
> > {
> > char errstr[MAX_STRING_LEN];
> > "
> >
> > "
> > And MAX_STRING_LEN is defined in include/httpd.h:298
> >
> > /** The default string length */
> > #define MAX_STRING_LEN HUGE_STRING_LEN
> >
> > /** The length of a Huge string */
> > #define HUGE_STRING_LEN 8192
> > "
> >
> > I tried to increase this value, recompile, and apparently I got a longer
> > message.
> > Please correct me if I am wrong... If this is true then can anyone tell
> me
> > why this "HUGE_STRING_LEN" value is a hard-coded value but not a
> > configurable option ?
>
> I can't speak for the apache core team, but such a limit usually is done
> for security reasons. Tracking buffer overflows in dynamically allocated
> memory can be rather tricky. Btw, what's your goal here? I get the
> feeling that you try to (ab)use the error log as a place to dump large
> blobs of information (traces?). Remember, this is an error log, not a
> place to dump Tolstoy's War and Peace ....
>
> HTH Ralf Mattes
>
>
> > Cheers, Vu
> that you try to (ab)use the error log as a place to dump large blobs of
> information (traces?). Remember, this is an error log, not a
> place to dump Tolstoy's War and Peace ....
>
> HTH Ralf Mattes
> >
> >
> > On 03/13/2013 11:16 AM, Eric Covener wrote:
> >> On Wed, Mar 13, 2013 at 6:01 AM, Hoang Vu Dang <dang....@gmail.com>
> wrote:
> >>> Hi guys,
> >>>
> >>> Is there any limit of the size of a message log entry? How to control
> >>> this ?
> >>>
> >>> I did this:
> >>>
> >>> ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, f->r,
> >>> "%s", buffer);
> >>>
> >>> And the buffer was truncated on the error log. I check the strlen of
> the
> >>> buffer and it was about 320K, and I got only around: ~ 8KB
> >> If it's more than PIPE_BUF, it won't be atomic and can be interleaved
> >> with other entries. Are you sure it's truncated and not just spread
> >> out?
>
