Core: skip special buffers on writing (ticket #981). A special last buffer with cl->buf->pos set to NULL can be present in a chain when writing request body if chunked encoding was used. This resulted in a NULL pointer dereference if it happened to be the only buffer left after a do...while loop iteration in ngx_write_chain_to_file(). The problem originally appeared in nginx 1.3.9 with chunked encoding support. Additionally, rev. 3832b608dc8d (nginx 1.9.13) changed the minimum number of buffers to trigger this from IOV_MAX (typically 1024) to NGX_IOVS_PREALLOCATE (typically 64). Fix is to skip such buffers in ngx_chain_to_iovec(), much like it is done in other places.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


CFLAGS = -zq -bt=nt -ot -op -oi -oe -s -bm $(CPU_OPT)

zlib.lib:
	cd $(ZLIB)

	wcl386 -c $(CFLAGS) adler32.c crc32.c deflate.c trees.c zutil.c &
		compress.c inflate.c inffast.c inftrees.c
	wlib -n zlib.lib adler32.obj crc32.obj deflate.obj trees.obj &
		zutil.obj compress.obj inflate.obj inffast.obj inftrees.obj