PowerPoint Presentation - Hacking Apache HTTP Server at Yahoo!

Not for the faint of heart

BUFF *outbuf = fb->cmp_outbuf;

fb->z.next_in = fb->outbase + fb->cmp_start_here;

fb->z.avail_in = fb->outcnt - fb->cmp_start_here;

fb->z.next_out = outbuf->outbase + outbuf->outcnt;

uInt len = fb->z.avail_out =

outbuf->bufsiz - outbuf->outcnt;

int err = deflate(&(fb->z), Z_SYNC_FLUSH);

fb->crc = crc32(fb->crc, fb->outbase+fb->cmp_start_here,

fb->outcnt - fb->cmp_start_here -

fb->z.avail_in);

len = len - fb->z.avail_out;

outbuf->outcnt += len;

fb->cmp_start_here = 0;


	Implementing the equivalent of mod_deflate without Apache2’s Filtered I/O framework meant touching a bunch of code in the core of httpd. This extract is just part of the patch. It gets worse. We had to modify the following:
	•buff.c
		•ap_bwrite(), bflush_core(), ap_bclose()
		•Introuduced new constants B_GZIP, B_GZIP_CHUNK
	•http_protocol.c
		•ap_send_http_header(), ap_finalize_request_protocol()