On Fri, Oct 24, 2008 at 01:04:41PM -0700, Adam Mitchell wrote:
> I am using the "-C" option to invoke the C preprocessor and include
> Apache's httpd.h in a dtrace script. This lets me dereference
> Apache's request_rec struct and pull some great per-request details.
>
> But it won't work "out of the box." Dtrace (or the D compiler in
> libdtrace) fails to parse the cpp output. I have to run cpp manually
> on httpd.h, saving the output to a monolithic dot-h file and then
> iteratively remove lines from that file when Dtrace complains about
> them until I have a "working" file. After that, it's just awesome.
>
> I guess my question is, is there any Dtrace debug flag that will give
> me more information on the parse error? Where are the "-x" (compiler
> and tracing) options defined? If I understood the parse error (found
> ABC but expecting XYZ), maybe I could contribute something back.
The D compiler defaults to the pre-ansi-C precompiler /usr/ccs/lib/cpp,
since that is the only one guaranteed to be on the system. Since it is
pre-ANSI C, constructs like "#" and "##" will confuse it.
You can specify a different preprocessor using the -xcpppath=/path/to/cpp
Cheers,
- jonathan
>
> Here's all I see now:
>
> $ sudo dtrace -32 -C -I /export/home/amitchel/include -s
> watchApacheRequestsTestingCPP.d -p 16770
> dtrace: failed to compile script watchApacheRequestsTestingCPP.d:
> "/export/home/amitchel/include/apr_thread_mutex.h", line 100: syntax error
> near "#"
>
>
> Line 100 is:
> APR_POOL_DECLARE_ACCESSOR(thread_mutex);
>
>
> My script is:
>
> $ cat watchApacheRequestsTestingCPP.d
> #!/usr/sbin/dtrace
>
> #include <httpd.h>
>
> pid$target:a.out:ap_process_request:entry
> {
>
> self->ts = timestamp;
> self->r = (request_rec*) copyin(arg0, sizeof(request_rec));
> self->uri = copyinstr((uintptr_t) self->r->uri);
>
> }
>
>
> pid$target:a.out:ap_process_request:return
> /self->ts/
> {
> @request_uris[self->uri] = quantize((timestamp - self->ts) / 1000000);
> self->ts = 0;
> self->uri = "err";
> }
>
> tick-5s
> {
> printa(@request_uris);
> }
> --
> This message posted from opensolaris.org
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