On Thu, 6 Dec 2001, Christopher Curtis wrote:
> The message isn't that large. I have both sender and recipient verify, as
> well as some system filters installed. Immediately after the process gets
> unstuck, ltrace continues with:
>
> mail:~# ltrace -p 7733
> strchr("_", '_') = "_"
> strncmp("message_body", "header_", 7) = 5
> strncmp("message_body", "h_", 2) = 5
> strcmp("message_body", "primary_hostname") = -3
> strcmp("message_body", "message_age") = 1
> strcmp("message_body", "n4") = -1
> strcmp("message_body", "message_precedence") = -14
> strcmp("message_body", "message_body_size") = -95
> strcmp("message_body", "message_body_end") = -95
> strcmp("message_body", "message_body") = 0
This shows that it is expanding the variable $message_body. That loop is
searching the list of variable names (by binary chop). So, this means
that the tight loop is happening when processing some expansion string
containing $message_body.
Do you have any such strings in your Exim configuration? Or in your Exim
filter? If so, what are they? What comes immediately before
$message_body?
Just a thought: are you using any regular expressions?
> Just from looking at this, exim appears to enter some sort of really tight
> loop with no system calls being made. Hopefully the trace will show which
> one.
Unfortunately, that information doesn't show where that code has been
called from.
> Also, I haven't looked at the source (obviously), but might I
> suggest replacing code that may look like this:
>
> for( index = 0; index < length; index++, ptr++ )
> strncpy( ptr, char, 1 );
I'd never write that! I wouldn't call a function to copy just one character.
So what is causing this trace?
> malloc(8192) = 0x080d9260
That's a malloc call.
> memcpy(0x080d9268, "", 0) = 0x080d9268
The code for that is
body[0] = 0;
Is your Exim compiled in some kind of debugging mode? I would have
expected a compiler to compile inline code for that statement.
> strncpy(0x080d9268, "This is a multi-part message in "..., 5000) =
> 0x080d9268
The code for that is (presumably)
lseek(deliver_datafile, start_offset, SEEK_SET);
len = read(deliver_datafile, body, len);
> strncpy(0x080da5f8, "a", 1) = 0x080da5f8
> strncpy(0x080da5f9, "\\", 1) = 0x080da5f9
> strncpy(0x080da5fa, "s", 1) = 0x080da5fa
> strncpy(0x080da5fb, "h", 1) = 0x080da5fb
> strncpy(0x080da5fc, "r", 1) = 0x080da5fc
> strncpy(0x080da5fd, "e", 1) = 0x080da5fd
No idea what all that is.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
