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 =	-q -O2 -tWM -w-8004 $(CPU_OPT)
PCREFLAGS =	-DHAVE_CONFIG_H -DPCRE_STATIC -DPOSIX_MALLOC_THRESHOLD=10 \
		-DSUPPORT_PCRE8 -DHAVE_MEMMOVE


pcre.lib:
	cd $(PCRE)

	bcc32 -c $(CFLAGS) -I. $(PCREFLAGS) pcre_*.c

	copy /y nul pcre.lst
	for %n in (*.obj) do @echo +%n ^^& >> pcre.lst
	echo + >> pcre.lst

	tlib pcre.lib @pcre.lst

pcre.h:
	cd $(PCRE)

	copy /y pcre.h.generic pcre.h
	copy /y config.h.generic config.h
	copy /y pcre_chartables.c.dist pcre_chartables.c