Re: ap_log_rerror limit size
On Wed, Mar 13, 2013 at 6:16 AM, Eric Covener cove...@gmail.com 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? Er if using a piped logger that is.
Re: ap_log_rerror limit size
Yes I am sure I can't find other entries related to that request. How to find whether I used PIPE_BUF and how to increase that BUF size ? On Mar 13, 2013, at 11:16 AM, Eric Covener cove...@gmail.com 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?
Re: ap_log_rerror limit size
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?
Re: ap_log_rerror limit size
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?
