Merge of r4275, r4276, r4278, r4279: Fixes for proxy_set_header, fastcgi/scgi/uwsgi_param inheritance: *) Fixed proxy_set_header inheritance with proxy_cache (ticket #45). Headers cleared with cache enabled (If-Modified-Since etc.) might be cleared in unrelated servers/locations without proxy_cache enabled if proxy_cache was used in some server/location. Example config which triggered the problem: proxy_set_header X-Test "test"; server { location /1 { proxy_cache name; proxy_pass ... } } server { location /2 { proxy_pass ... } } Another one: server { proxy_cache name; location /1 { proxy_pass ... } location /2 { proxy_cache off; proxy_pass ... } } In both cases If-Modified-Since header wasn't sent to backend in location /2. Fix is to not modify conf->headers_source, but instead merge user-supplied headers from conf->headers_source and default headers (either cache or not) into separate headers_merged array. *) Fixed proxy_set_header inheritance with proxy_set_body. *) Separate functions to merge fastcgi/scgi/uwsgi params. No functional changes. *) Fixed fastcgi/scgi/uwsgi_param inheritance. The following problems were fixed: 1. Directive fastcgi_cache affected headers sent to backends in unrelated servers / locations (see ticket #45). 2. If-Unmodified-Since, If-Match and If-Range headers were sent to backends if fastcgi_cache was used. 3. Cache-related headers were sent to backends if there were no fastcgi_param directives and fastcgi_cache was used at server level.

/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_SHMTX_H_INCLUDED_
#define _NGX_SHMTX_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


typedef struct {
#if (NGX_HAVE_ATOMIC_OPS)
    ngx_atomic_t  *lock;
#if (NGX_HAVE_POSIX_SEM)
    ngx_uint_t     semaphore;
    sem_t          sem;
#endif
#else
    ngx_fd_t       fd;
    u_char        *name;
#endif
    ngx_uint_t     spin;
} ngx_shmtx_t;


ngx_int_t ngx_shmtx_create(ngx_shmtx_t *mtx, void *addr, u_char *name);
void ngx_shmtx_destory(ngx_shmtx_t *mtx);
ngx_uint_t ngx_shmtx_trylock(ngx_shmtx_t *mtx);
void ngx_shmtx_lock(ngx_shmtx_t *mtx);
void ngx_shmtx_unlock(ngx_shmtx_t *mtx);


#endif /* _NGX_SHMTX_H_INCLUDED_ */