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.
 */


#ifndef _NGX_DARWIN_H_INCLUDED_
#define _NGX_DARWIN_H_INCLUDED_


void ngx_debug_init(void);
ngx_chain_t *ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in,
    off_t limit);

extern int       ngx_darwin_kern_osreldate;
extern int       ngx_darwin_hw_ncpu;
extern u_long    ngx_darwin_net_inet_tcp_sendspace;

extern ngx_uint_t  ngx_debug_malloc;


#endif /* _NGX_DARWIN_H_INCLUDED_ */