view src/http/modules/ngx_http_scgi_module.c @ 4247:b79dbadb3d5e stable-1.0

Merging r4147, r4148, r4149, r4150, r4207: Fixes of combination of error_page and return directives: *) Fix for incorrect 201 replies from dav module. Replies with 201 code contain body, and we should clearly indicate it's empty if it's empty. Before 0.8.32 chunked was explicitly disabled for 201 replies and as a result empty body was indicated by connection close (not perfect, but worked). Since 0.8.32 chunked is enabled, and this causes incorrect responses from dav module when HTTP/1.1 is used: with "Transfer-Encoding: chunked" but no chunks at all. Fix is to actually return empty body in special response handler instead of abusing r->header_only flag. See here for initial report: http://mailman.nginx.org/pipermail/nginx-ru/2010-October/037535.html *) Fix for double content when return is used in error_page handler. Test case: location / { error_page 405 /nope; return 405; } location /nope { return 200; } This is expected to return 405 with empty body, but in 0.8.42+ will return builtin 405 error page as well (though not counted in Content-Length, thus breaking protocol). Fix is to use status provided by rewrite script execution in case it's less than NGX_HTTP_BAD_REQUEST even if r->error_status set. This check is in line with one in ngx_http_script_return_code(). Note that this patch also changes behaviour for "return 302 ..." and "rewrite ... redirect" used as error handler. E.g. location / { error_page 405 /redirect; return 405; } location /redirect { rewrite ^ http://example.com/; } will actually return redirect to "http://example.com/" instead of builtin 405 error page with meaningless Location header. This looks like correct change and it's in line with what happens on e.g. directory redirects in error handlers. *) Fix for "return 202" not discarding body. Big POST (not fully preread) to a location / { return 202; } resulted in incorrect behaviour due to "return" code path not calling ngx_http_discard_request_body(). The same applies to all "return" used with 2xx/3xx codes except 201 and 204, and to all "return ... text" uses. Fix is to add ngx_http_discard_request_body() call to ngx_http_send_response() function where it looks appropriate. Discard body call from emtpy gif module removed as it's now redundant. Reported by Pyry Hakulinen, see http://mailman.nginx.org/pipermail/nginx/2011-August/028503.html *) Incorrect special case for "return 204" removed. The special case in question leads to replies without body in configuration like location / { error_page 404 /zero; return 404; } location /zero { return 204; } while replies with empty body are expected per protocol specs. Correct one will look like if (status == NGX_HTTP_NO_CONTENT) { rc = ngx_http_send_header(r); if (rc == NGX_ERROR || r->header_only) { return rc; } return ngx_http_send_special(r, NGX_HTTP_LAST); } though it looks like it's better to drop this special case at all. *) Clear old Location header (if any) while adding a new one. This prevents incorrect behaviour when another redirect is issued within error_page 302 handler.
author Igor Sysoev <igor@sysoev.ru>
date Tue, 01 Nov 2011 13:45:33 +0000
parents 36d2cd2e361d
children 9d59a8eda373
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Manlio Perillo (manlio.perillo@gmail.com)
 */


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


typedef struct {
    ngx_http_upstream_conf_t   upstream;

    ngx_array_t               *flushes;
    ngx_array_t               *params_len;
    ngx_array_t               *params;
    ngx_array_t               *params_source;

    ngx_hash_t                 headers_hash;
    ngx_uint_t                 header_params;

    ngx_array_t               *scgi_lengths;
    ngx_array_t               *scgi_values;

#if (NGX_HTTP_CACHE)
    ngx_http_complex_value_t   cache_key;
#endif
} ngx_http_scgi_loc_conf_t;


static ngx_int_t ngx_http_scgi_eval(ngx_http_request_t *r,
    ngx_http_scgi_loc_conf_t *scf);
static ngx_int_t ngx_http_scgi_create_request(ngx_http_request_t *r);
static ngx_int_t ngx_http_scgi_reinit_request(ngx_http_request_t *r);
static ngx_int_t ngx_http_scgi_process_status_line(ngx_http_request_t *r);
static ngx_int_t ngx_http_scgi_process_header(ngx_http_request_t *r);
static ngx_int_t ngx_http_scgi_process_header(ngx_http_request_t *r);
static void ngx_http_scgi_abort_request(ngx_http_request_t *r);
static void ngx_http_scgi_finalize_request(ngx_http_request_t *r, ngx_int_t rc);

static void *ngx_http_scgi_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_scgi_merge_loc_conf(ngx_conf_t *cf, void *parent,
    void *child);

static char *ngx_http_scgi_pass(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static char *ngx_http_scgi_store(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);

#if (NGX_HTTP_CACHE)
static ngx_int_t ngx_http_scgi_create_key(ngx_http_request_t *r);
static char *ngx_http_scgi_cache(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_scgi_cache_key(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
#endif


static ngx_conf_bitmask_t ngx_http_scgi_next_upstream_masks[] = {
    { ngx_string("error"), NGX_HTTP_UPSTREAM_FT_ERROR },
    { ngx_string("timeout"), NGX_HTTP_UPSTREAM_FT_TIMEOUT },
    { ngx_string("invalid_header"), NGX_HTTP_UPSTREAM_FT_INVALID_HEADER },
    { ngx_string("http_500"), NGX_HTTP_UPSTREAM_FT_HTTP_500 },
    { ngx_string("http_503"), NGX_HTTP_UPSTREAM_FT_HTTP_503 },
    { ngx_string("http_404"), NGX_HTTP_UPSTREAM_FT_HTTP_404 },
    { ngx_string("updating"), NGX_HTTP_UPSTREAM_FT_UPDATING },
    { ngx_string("off"), NGX_HTTP_UPSTREAM_FT_OFF },
    { ngx_null_string, 0 }
};


ngx_module_t  ngx_http_scgi_module;


static ngx_command_t ngx_http_scgi_commands[] = {

    { ngx_string("scgi_pass"),
      NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF|NGX_CONF_TAKE1,
      ngx_http_scgi_pass,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("scgi_store"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_scgi_store,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("scgi_store_access"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE123,
      ngx_conf_set_access_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.store_access),
      NULL },

    { ngx_string("scgi_ignore_client_abort"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.ignore_client_abort),
      NULL },

    { ngx_string("scgi_bind"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_upstream_bind_set_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.local),
      NULL },

    { ngx_string("scgi_connect_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.connect_timeout),
      NULL },

    { ngx_string("scgi_send_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.send_timeout),
      NULL },

    { ngx_string("scgi_buffer_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.buffer_size),
      NULL },

    { ngx_string("scgi_pass_request_headers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.pass_request_headers),
      NULL },

    { ngx_string("scgi_pass_request_body"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.pass_request_body),
      NULL },

    { ngx_string("scgi_intercept_errors"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.intercept_errors),
      NULL },

    { ngx_string("scgi_read_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.read_timeout),
      NULL },

    { ngx_string("scgi_buffers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
      ngx_conf_set_bufs_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.bufs),
      NULL },

    { ngx_string("scgi_busy_buffers_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.busy_buffers_size_conf),
      NULL },

#if (NGX_HTTP_CACHE)

    { ngx_string("scgi_cache"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_scgi_cache,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("scgi_cache_key"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_scgi_cache_key,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("scgi_cache_path"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_2MORE,
      ngx_http_file_cache_set_slot,
      0,
      0,
      &ngx_http_scgi_module },

    { ngx_string("scgi_cache_bypass"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_set_predicate_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_bypass),
      NULL },

    { ngx_string("scgi_no_cache"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_set_predicate_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.no_cache),
      NULL },

    { ngx_string("scgi_cache_valid"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_file_cache_valid_set_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_valid),
      NULL },

    { ngx_string("scgi_cache_min_uses"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_min_uses),
      NULL },

    { ngx_string("scgi_cache_use_stale"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_use_stale),
      &ngx_http_scgi_next_upstream_masks },

    { ngx_string("scgi_cache_methods"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_methods),
      &ngx_http_upstream_cache_method_mask },

#endif

    { ngx_string("scgi_temp_path"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1234,
      ngx_conf_set_path_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.temp_path),
      NULL },

    { ngx_string("scgi_max_temp_file_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.max_temp_file_size_conf),
      NULL },

    { ngx_string("scgi_temp_file_write_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.temp_file_write_size_conf),
      NULL },

    { ngx_string("scgi_next_upstream"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.next_upstream),
      &ngx_http_scgi_next_upstream_masks },

    { ngx_string("scgi_param"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
      ngx_conf_set_keyval_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, params_source),
      NULL },

    { ngx_string("scgi_pass_header"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_array_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.pass_headers),
      NULL },

    { ngx_string("scgi_hide_header"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_array_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.hide_headers),
      NULL },

    { ngx_string("scgi_ignore_headers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_scgi_loc_conf_t, upstream.ignore_headers),
      &ngx_http_upstream_ignore_headers_masks },

      ngx_null_command
};


static ngx_http_module_t ngx_http_scgi_module_ctx = {
    NULL,                                  /* preconfiguration */
    NULL,                                  /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    ngx_http_scgi_create_loc_conf,         /* create location configuration */
    ngx_http_scgi_merge_loc_conf           /* merge location configuration */
};


ngx_module_t ngx_http_scgi_module = {
    NGX_MODULE_V1,
    &ngx_http_scgi_module_ctx,             /* module context */
    ngx_http_scgi_commands,                /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_str_t ngx_http_scgi_hide_headers[] = {
    ngx_string("Status"),
    ngx_string("X-Accel-Expires"),
    ngx_string("X-Accel-Redirect"),
    ngx_string("X-Accel-Limit-Rate"),
    ngx_string("X-Accel-Buffering"),
    ngx_string("X-Accel-Charset"),
    ngx_null_string
};


#if (NGX_HTTP_CACHE)

static ngx_keyval_t  ngx_http_scgi_cache_headers[] = {
    { ngx_string("HTTP_IF_MODIFIED_SINCE"), ngx_string("") },
    { ngx_string("HTTP_IF_UNMODIFIED_SINCE"), ngx_string("") },
    { ngx_string("HTTP_IF_NONE_MATCH"), ngx_string("") },
    { ngx_string("HTTP_IF_MATCH"), ngx_string("") },
    { ngx_string("HTTP_RANGE"), ngx_string("") },
    { ngx_string("HTTP_IF_RANGE"), ngx_string("") },
    { ngx_null_string, ngx_null_string }
};

#endif


static ngx_path_init_t ngx_http_scgi_temp_path = {
    ngx_string(NGX_HTTP_SCGI_TEMP_PATH), { 1, 2, 0 }
};


static ngx_int_t
ngx_http_scgi_handler(ngx_http_request_t *r)
{
    ngx_int_t                  rc;
    ngx_http_status_t         *status;
    ngx_http_upstream_t       *u;
    ngx_http_scgi_loc_conf_t  *scf;

    if (r->subrequest_in_memory) {
        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
                      "ngx_http_scgi_module does not support "
                      "subrequests in memory");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    if (ngx_http_upstream_create(r) != NGX_OK) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    status = ngx_pcalloc(r->pool, sizeof(ngx_http_status_t));
    if (status == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    ngx_http_set_ctx(r, status, ngx_http_scgi_module);

    scf = ngx_http_get_module_loc_conf(r, ngx_http_scgi_module);

    if (scf->scgi_lengths) {
        if (ngx_http_scgi_eval(r, scf) != NGX_OK) {
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }
    }

    u = r->upstream;

    ngx_str_set(&u->schema, "scgi://");
    u->output.tag = (ngx_buf_tag_t) &ngx_http_scgi_module;

    u->conf = &scf->upstream;

#if (NGX_HTTP_CACHE)
    u->create_key = ngx_http_scgi_create_key;
#endif
    u->create_request = ngx_http_scgi_create_request;
    u->reinit_request = ngx_http_scgi_reinit_request;
    u->process_header = ngx_http_scgi_process_status_line;
    u->abort_request = ngx_http_scgi_abort_request;
    u->finalize_request = ngx_http_scgi_finalize_request;

    u->buffering = 1;

    u->pipe = ngx_pcalloc(r->pool, sizeof(ngx_event_pipe_t));
    if (u->pipe == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    u->pipe->input_filter = ngx_event_pipe_copy_input_filter;
    u->pipe->input_ctx = r;

    rc = ngx_http_read_client_request_body(r, ngx_http_upstream_init);

    if (rc >= NGX_HTTP_SPECIAL_RESPONSE) {
        return rc;
    }

    return NGX_DONE;
}


static ngx_int_t
ngx_http_scgi_eval(ngx_http_request_t *r, ngx_http_scgi_loc_conf_t * scf)
{
    ngx_url_t             url;
    ngx_http_upstream_t  *u;

    ngx_memzero(&url, sizeof(ngx_url_t));

    if (ngx_http_script_run(r, &url.url, scf->scgi_lengths->elts, 0,
                            scf->scgi_values->elts)
        == NULL)
    {
        return NGX_ERROR;
    }

    url.no_resolve = 1;

    if (ngx_parse_url(r->pool, &url) != NGX_OK) {
        if (url.err) {
            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                          "%s in upstream \"%V\"", url.err, &url.url);
        }

        return NGX_ERROR;
    }

    u = r->upstream;

    u->resolved = ngx_pcalloc(r->pool, sizeof(ngx_http_upstream_resolved_t));
    if (u->resolved == NULL) {
        return NGX_ERROR;
    }

    if (url.addrs && url.addrs[0].sockaddr) {
        u->resolved->sockaddr = url.addrs[0].sockaddr;
        u->resolved->socklen = url.addrs[0].socklen;
        u->resolved->naddrs = 1;
        u->resolved->host = url.addrs[0].name;

    } else {
        u->resolved->host = url.host;
        u->resolved->port = url.port;
        u->resolved->no_port = url.no_port;
    }

    return NGX_OK;
}


#if (NGX_HTTP_CACHE)

static ngx_int_t
ngx_http_scgi_create_key(ngx_http_request_t *r)
{
    ngx_str_t                 *key;
    ngx_http_scgi_loc_conf_t  *scf;

    key = ngx_array_push(&r->cache->keys);
    if (key == NULL) {
        return NGX_ERROR;
    }

    scf = ngx_http_get_module_loc_conf(r, ngx_http_scgi_module);

    if (ngx_http_complex_value(r, &scf->cache_key, key) != NGX_OK) {
        return NGX_ERROR;
    }

    return NGX_OK;
}

#endif


static ngx_int_t
ngx_http_scgi_create_request(ngx_http_request_t *r)
{
    u_char                        ch, *key, *val, *lowcase_key;
    size_t                        len, allocated;
    ngx_buf_t                    *b;
    ngx_str_t                    *content_length;
    ngx_uint_t                    i, n, hash, header_params;
    ngx_chain_t                  *cl, *body;
    ngx_list_part_t              *part;
    ngx_table_elt_t              *header, **ignored;
    ngx_http_script_code_pt       code;
    ngx_http_script_engine_t      e, le;
    ngx_http_scgi_loc_conf_t     *scf;
    ngx_http_script_len_code_pt   lcode;
    static ngx_str_t              zero = ngx_string("0");

    content_length = r->headers_in.content_length ?
                         &r->headers_in.content_length->value : &zero;

    len = sizeof("CONTENT_LENGTH") + content_length->len + 1;

    header_params = 0;
    ignored = NULL;

    scf = ngx_http_get_module_loc_conf(r, ngx_http_scgi_module);

    if (scf->params_len) {
        ngx_memzero(&le, sizeof(ngx_http_script_engine_t));

        ngx_http_script_flush_no_cacheable_variables(r, scf->flushes);
        le.flushed = 1;

        le.ip = scf->params_len->elts;
        le.request = r;

        while (*(uintptr_t *) le.ip) {

            lcode = *(ngx_http_script_len_code_pt *) le.ip;
            len += lcode(&le);

            while (*(uintptr_t *) le.ip) {
                lcode = *(ngx_http_script_len_code_pt *) le.ip;
                len += lcode(&le) + 1;
            }
            le.ip += sizeof(uintptr_t);
        }
    }

    if (scf->upstream.pass_request_headers) {

        allocated = 0;
        lowcase_key = NULL;

        if (scf->header_params) {
            n = 0;
            part = &r->headers_in.headers.part;

            while (part) {
                n += part->nelts;
                part = part->next;
            }

            ignored = ngx_palloc(r->pool, n * sizeof(void *));
            if (ignored == NULL) {
                return NGX_ERROR;
            }
        }

        part = &r->headers_in.headers.part;
        header = part->elts;

        for (i = 0; /* void */; i++) {

            if (i >= part->nelts) {
                if (part->next == NULL) {
                    break;
                }

                part = part->next;
                header = part->elts;
                i = 0;
            }

            if (scf->header_params) {
                if (allocated < header[i].key.len) {
                    allocated = header[i].key.len + 16;
                    lowcase_key = ngx_pnalloc(r->pool, allocated);
                    if (lowcase_key == NULL) {
                        return NGX_ERROR;
                    }
                }

                hash = 0;

                for (n = 0; n < header[i].key.len; n++) {
                    ch = header[i].key.data[n];

                    if (ch >= 'A' && ch <= 'Z') {
                        ch |= 0x20;

                    } else if (ch == '-') {
                        ch = '_';
                    }

                    hash = ngx_hash(hash, ch);
                    lowcase_key[n] = ch;
                }

                if (ngx_hash_find(&scf->headers_hash, hash, lowcase_key, n)) {
                    ignored[header_params++] = &header[i];
                    continue;
                }
            }

            len += sizeof("HTTP_") - 1 + header[i].key.len + 1
                + header[i].value.len + 1;
        }
    }

    /* netstring: "length:" + packet + "," */

    b = ngx_create_temp_buf(r->pool, NGX_SIZE_T_LEN + 1 + len + 1);
    if (b == NULL) {
        return NGX_ERROR;
    }

    cl = ngx_alloc_chain_link(r->pool);
    if (cl == NULL) {
        return NGX_ERROR;
    }

    cl->buf = b;

    b->last = ngx_snprintf(b->last,
                           NGX_SIZE_T_LEN + 1 + sizeof("CONTENT_LENGTH")
                           + NGX_OFF_T_LEN + 1,
                           "%ui:CONTENT_LENGTH%Z%V%Z",
                           len, content_length);

    if (scf->params_len) {
        ngx_memzero(&e, sizeof(ngx_http_script_engine_t));

        e.ip = scf->params->elts;
        e.pos = b->last;
        e.request = r;
        e.flushed = 1;

        while (*(uintptr_t *) e.ip) {

#if (NGX_DEBUG)
            key = e.pos;
#endif
            code = *(ngx_http_script_code_pt *) e.ip;
            code((ngx_http_script_engine_t *) & e);

#if (NGX_DEBUG)
            val = e.pos;
#endif
            while (*(uintptr_t *) e.ip) {
                code = *(ngx_http_script_code_pt *) e.ip;
                code((ngx_http_script_engine_t *) &e);
            }
            *e.pos++ = '\0';
            e.ip += sizeof(uintptr_t);

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "scgi param: \"%s: %s\"", key, val);
        }

        b->last = e.pos;
    }

    if (scf->upstream.pass_request_headers) {

        part = &r->headers_in.headers.part;
        header = part->elts;

        for (i = 0; /* void */; i++) {

            if (i >= part->nelts) {
                if (part->next == NULL) {
                    break;
                }

                part = part->next;
                header = part->elts;
                i = 0;
            }

            for (n = 0; n < header_params; n++) {
                if (&header[i] == ignored[n]) {
                    goto next;
                }
            }

            key = b->last;
            b->last = ngx_cpymem(key, "HTTP_", sizeof("HTTP_") - 1);

            for (n = 0; n < header[i].key.len; n++) {
                ch = header[i].key.data[n];

                if (ch >= 'a' && ch <= 'z') {
                    ch &= ~0x20;

                } else if (ch == '-') {
                    ch = '_';
                }

                *b->last++ = ch;
            }

            *b->last++ = (u_char) 0;

            val = b->last;
            b->last = ngx_copy(val, header[i].value.data, header[i].value.len);
            *b->last++ = (u_char) 0;

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "scgi param: \"%s: %s\"", key, val);

        next:

            continue;
         }
    }

    *b->last++ = (u_char) ',';

    if (scf->upstream.pass_request_body) {
        body = r->upstream->request_bufs;
        r->upstream->request_bufs = cl;

        while (body) {
            b = ngx_alloc_buf(r->pool);
            if (b == NULL) {
                return NGX_ERROR;
            }

            ngx_memcpy(b, body->buf, sizeof(ngx_buf_t));

            cl->next = ngx_alloc_chain_link(r->pool);
            if (cl->next == NULL) {
                return NGX_ERROR;
            }

            cl = cl->next;
            cl->buf = b;

            body = body->next;
        }

    } else {
        r->upstream->request_bufs = cl;
    }

    cl->next = NULL;

    return NGX_OK;
}


static ngx_int_t
ngx_http_scgi_reinit_request(ngx_http_request_t *r)
{
    ngx_http_status_t  *status;

    status = ngx_http_get_module_ctx(r, ngx_http_scgi_module);

    if (status == NULL) {
        return NGX_OK;
    }

    status->code = 0;
    status->count = 0;
    status->start = NULL;
    status->end = NULL;

    r->upstream->process_header = ngx_http_scgi_process_status_line;

    return NGX_OK;
}


static ngx_int_t
ngx_http_scgi_process_status_line(ngx_http_request_t *r)
{
    size_t                len;
    ngx_int_t             rc;
    ngx_http_status_t    *status;
    ngx_http_upstream_t  *u;

    status = ngx_http_get_module_ctx(r, ngx_http_scgi_module);

    if (status == NULL) {
        return NGX_ERROR;
    }

    u = r->upstream;

    rc = ngx_http_parse_status_line(r, &u->buffer, status);

    if (rc == NGX_AGAIN) {
        return rc;
    }

    if (rc == NGX_ERROR) {

        r->http_version = NGX_HTTP_VERSION_9;

        u->process_header = ngx_http_scgi_process_header;

        return ngx_http_scgi_process_header(r);
    }

    if (u->state) {
        u->state->status = status->code;
    }

    u->headers_in.status_n = status->code;

    len = status->end - status->start;
    u->headers_in.status_line.len = len;

    u->headers_in.status_line.data = ngx_pnalloc(r->pool, len);
    if (u->headers_in.status_line.data == NULL) {
        return NGX_ERROR;
    }

    ngx_memcpy(u->headers_in.status_line.data, status->start, len);

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http scgi status %ui \"%V\"",
                   u->headers_in.status_n, &u->headers_in.status_line);

    u->process_header = ngx_http_scgi_process_header;

    return ngx_http_scgi_process_header(r);
}


static ngx_int_t
ngx_http_scgi_process_header(ngx_http_request_t *r)
{
    ngx_str_t                      *status_line;
    ngx_int_t                       rc, status;
    ngx_table_elt_t                *h;
    ngx_http_upstream_t            *u;
    ngx_http_upstream_header_t     *hh;
    ngx_http_upstream_main_conf_t  *umcf;

    umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);

    for ( ;; ) {

        rc = ngx_http_parse_header_line(r, &r->upstream->buffer, 1);

        if (rc == NGX_OK) {

            /* a header line has been parsed successfully */

            h = ngx_list_push(&r->upstream->headers_in.headers);
            if (h == NULL) {
                return NGX_ERROR;
            }

            h->hash = r->header_hash;

            h->key.len = r->header_name_end - r->header_name_start;
            h->value.len = r->header_end - r->header_start;

            h->key.data = ngx_pnalloc(r->pool,
                                      h->key.len + 1 + h->value.len + 1
                                      + h->key.len);
            if (h->key.data == NULL) {
                return NGX_ERROR;
            }

            h->value.data = h->key.data + h->key.len + 1;
            h->lowcase_key = h->key.data + h->key.len + 1 + h->value.len + 1;

            ngx_cpystrn(h->key.data, r->header_name_start, h->key.len + 1);
            ngx_cpystrn(h->value.data, r->header_start, h->value.len + 1);

            if (h->key.len == r->lowcase_index) {
                ngx_memcpy(h->lowcase_key, r->lowcase_header, h->key.len);

            } else {
                ngx_strlow(h->lowcase_key, h->key.data, h->key.len);
            }

            hh = ngx_hash_find(&umcf->headers_in_hash, h->hash,
                               h->lowcase_key, h->key.len);

            if (hh && hh->handler(r, h, hh->offset) != NGX_OK) {
                return NGX_ERROR;
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http scgi header: \"%V: %V\"", &h->key, &h->value);

            continue;
        }

        if (rc == NGX_HTTP_PARSE_HEADER_DONE) {

            /* a whole header has been parsed successfully */

            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http scgi header done");

            if (r->http_version > NGX_HTTP_VERSION_9) {
                return NGX_OK;
            }

            u = r->upstream;

            if (u->headers_in.status) {
                status_line = &u->headers_in.status->value;

                status = ngx_atoi(status_line->data, 3);
                if (status == NGX_ERROR) {
                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                                  "upstream sent invalid status \"%V\"",
                                  status_line);
                    return NGX_HTTP_UPSTREAM_INVALID_HEADER;
                }

                r->http_version = NGX_HTTP_VERSION_10;
                u->headers_in.status_n = status;
                u->headers_in.status_line = *status_line;

            } else if (u->headers_in.location) {
                r->http_version = NGX_HTTP_VERSION_10;
                u->headers_in.status_n = 302;
                ngx_str_set(&u->headers_in.status_line,
                            "302 Moved Temporarily");

            } else {
                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                              "upstream sent neither valid HTTP/1.0 header "
                              "nor \"Status\" header line");
                u->headers_in.status_n = 200;
                ngx_str_set(&u->headers_in.status_line, "200 OK");
            }

            if (u->state) {
                u->state->status = u->headers_in.status_n;
            }

            return NGX_OK;
        }

        if (rc == NGX_AGAIN) {
            return NGX_AGAIN;
        }

        /* there was error while a header line parsing */

        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "upstream sent invalid header");

        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
    }
}


static void
ngx_http_scgi_abort_request(ngx_http_request_t *r)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "abort http scgi request");

    return;
}


static void
ngx_http_scgi_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "finalize http scgi request");

    return;
}


static void *
ngx_http_scgi_create_loc_conf(ngx_conf_t *cf)
{
    ngx_http_scgi_loc_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_scgi_loc_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    conf->upstream.store = NGX_CONF_UNSET;
    conf->upstream.store_access = NGX_CONF_UNSET_UINT;
    conf->upstream.buffering = NGX_CONF_UNSET;
    conf->upstream.ignore_client_abort = NGX_CONF_UNSET;

    conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
    conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
    conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;

    conf->upstream.send_lowat = NGX_CONF_UNSET_SIZE;
    conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;

    conf->upstream.busy_buffers_size_conf = NGX_CONF_UNSET_SIZE;
    conf->upstream.max_temp_file_size_conf = NGX_CONF_UNSET_SIZE;
    conf->upstream.temp_file_write_size_conf = NGX_CONF_UNSET_SIZE;

    conf->upstream.pass_request_headers = NGX_CONF_UNSET;
    conf->upstream.pass_request_body = NGX_CONF_UNSET;

#if (NGX_HTTP_CACHE)
    conf->upstream.cache = NGX_CONF_UNSET_PTR;
    conf->upstream.cache_min_uses = NGX_CONF_UNSET_UINT;
    conf->upstream.cache_bypass = NGX_CONF_UNSET_PTR;
    conf->upstream.no_cache = NGX_CONF_UNSET_PTR;
    conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
#endif

    conf->upstream.hide_headers = NGX_CONF_UNSET_PTR;
    conf->upstream.pass_headers = NGX_CONF_UNSET_PTR;

    conf->upstream.intercept_errors = NGX_CONF_UNSET;

    /* "scgi_cyclic_temp_file" is disabled */
    conf->upstream.cyclic_temp_file = 0;

    ngx_str_set(&conf->upstream.module, "scgi");

    return conf;
}


static char *
ngx_http_scgi_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_scgi_loc_conf_t *prev = parent;
    ngx_http_scgi_loc_conf_t *conf = child;

    u_char                       *p;
    size_t                        size;
    uintptr_t                    *code;
    ngx_uint_t                    i;
    ngx_array_t                   headers_names;
    ngx_keyval_t                 *src;
    ngx_hash_key_t               *hk;
    ngx_hash_init_t               hash;
    ngx_http_core_loc_conf_t     *clcf;
    ngx_http_script_compile_t     sc;
    ngx_http_script_copy_code_t  *copy;

    if (conf->upstream.store != 0) {
        ngx_conf_merge_value(conf->upstream.store, prev->upstream.store, 0);

        if (conf->upstream.store_lengths == NULL) {
            conf->upstream.store_lengths = prev->upstream.store_lengths;
            conf->upstream.store_values = prev->upstream.store_values;
        }
    }

    ngx_conf_merge_uint_value(conf->upstream.store_access,
                              prev->upstream.store_access, 0600);

    ngx_conf_merge_value(conf->upstream.buffering,
                              prev->upstream.buffering, 1);

    ngx_conf_merge_value(conf->upstream.ignore_client_abort,
                              prev->upstream.ignore_client_abort, 0);

    ngx_conf_merge_msec_value(conf->upstream.connect_timeout,
                              prev->upstream.connect_timeout, 60000);

    ngx_conf_merge_msec_value(conf->upstream.send_timeout,
                              prev->upstream.send_timeout, 60000);

    ngx_conf_merge_msec_value(conf->upstream.read_timeout,
                              prev->upstream.read_timeout, 60000);

    ngx_conf_merge_size_value(conf->upstream.send_lowat,
                              prev->upstream.send_lowat, 0);

    ngx_conf_merge_size_value(conf->upstream.buffer_size,
                              prev->upstream.buffer_size,
                              (size_t) ngx_pagesize);


    ngx_conf_merge_bufs_value(conf->upstream.bufs, prev->upstream.bufs,
                              8, ngx_pagesize);

    if (conf->upstream.bufs.num < 2) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "there must be at least 2 \"scgi_buffers\"");
        return NGX_CONF_ERROR;
    }


    size = conf->upstream.buffer_size;
    if (size < conf->upstream.bufs.size) {
        size = conf->upstream.bufs.size;
    }


    ngx_conf_merge_size_value(conf->upstream.busy_buffers_size_conf,
                              prev->upstream.busy_buffers_size_conf,
                              NGX_CONF_UNSET_SIZE);

    if (conf->upstream.busy_buffers_size_conf == NGX_CONF_UNSET_SIZE) {
        conf->upstream.busy_buffers_size = 2 * size;
    } else {
        conf->upstream.busy_buffers_size =
            conf->upstream.busy_buffers_size_conf;
    }

    if (conf->upstream.busy_buffers_size < size) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
            "\"scgi_busy_buffers_size\" must be equal or bigger "
            "than maximum of the value of \"scgi_buffer_size\" and "
            "one of the \"scgi_buffers\"");

        return NGX_CONF_ERROR;
    }

    if (conf->upstream.busy_buffers_size
        > (conf->upstream.bufs.num - 1) * conf->upstream.bufs.size)
    {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
            "\"scgi_busy_buffers_size\" must be less than "
            "the size of all \"scgi_buffers\" minus one buffer");

        return NGX_CONF_ERROR;
    }


    ngx_conf_merge_size_value(conf->upstream.temp_file_write_size_conf,
                              prev->upstream.temp_file_write_size_conf,
                              NGX_CONF_UNSET_SIZE);

    if (conf->upstream.temp_file_write_size_conf == NGX_CONF_UNSET_SIZE) {
        conf->upstream.temp_file_write_size = 2 * size;
    } else {
        conf->upstream.temp_file_write_size =
            conf->upstream.temp_file_write_size_conf;
    }

    if (conf->upstream.temp_file_write_size < size) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
            "\"scgi_temp_file_write_size\" must be equal or bigger than "
            "maximum of the value of \"scgi_buffer_size\" and "
            "one of the \"scgi_buffers\"");

        return NGX_CONF_ERROR;
    }


    ngx_conf_merge_size_value(conf->upstream.max_temp_file_size_conf,
                              prev->upstream.max_temp_file_size_conf,
                              NGX_CONF_UNSET_SIZE);

    if (conf->upstream.max_temp_file_size_conf == NGX_CONF_UNSET_SIZE) {
        conf->upstream.max_temp_file_size = 1024 * 1024 * 1024;
    } else {
        conf->upstream.max_temp_file_size =
            conf->upstream.max_temp_file_size_conf;
    }

    if (conf->upstream.max_temp_file_size != 0
        && conf->upstream.max_temp_file_size < size) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
            "\"scgi_max_temp_file_size\" must be equal to zero to disable "
            "the temporary files usage or must be equal or bigger than "
            "maximum of the value of \"scgi_buffer_size\" and "
            "one of the \"scgi_buffers\"");

        return NGX_CONF_ERROR;
    }


    ngx_conf_merge_bitmask_value(conf->upstream.ignore_headers,
                                 prev->upstream.ignore_headers,
                                 NGX_CONF_BITMASK_SET);


    ngx_conf_merge_bitmask_value(conf->upstream.next_upstream,
                                 prev->upstream.next_upstream,
                                 (NGX_CONF_BITMASK_SET
                                  |NGX_HTTP_UPSTREAM_FT_ERROR
                                  |NGX_HTTP_UPSTREAM_FT_TIMEOUT));

    if (conf->upstream.next_upstream & NGX_HTTP_UPSTREAM_FT_OFF) {
        conf->upstream.next_upstream = NGX_CONF_BITMASK_SET
                                       |NGX_HTTP_UPSTREAM_FT_OFF;
    }

    if (ngx_conf_merge_path_value(cf, &conf->upstream.temp_path,
                                  prev->upstream.temp_path,
                                  &ngx_http_scgi_temp_path)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

#if (NGX_HTTP_CACHE)

    ngx_conf_merge_ptr_value(conf->upstream.cache,
                              prev->upstream.cache, NULL);

    if (conf->upstream.cache && conf->upstream.cache->data == NULL) {
        ngx_shm_zone_t  *shm_zone;

        shm_zone = conf->upstream.cache;

        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "\"scgi_cache\" zone \"%V\" is unknown",
                           &shm_zone->shm.name);

        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_uint_value(conf->upstream.cache_min_uses,
                              prev->upstream.cache_min_uses, 1);

    ngx_conf_merge_bitmask_value(conf->upstream.cache_use_stale,
                              prev->upstream.cache_use_stale,
                              (NGX_CONF_BITMASK_SET
                               |NGX_HTTP_UPSTREAM_FT_OFF));

    if (conf->upstream.cache_use_stale & NGX_HTTP_UPSTREAM_FT_OFF) {
        conf->upstream.cache_use_stale = NGX_CONF_BITMASK_SET
                                         |NGX_HTTP_UPSTREAM_FT_OFF;
    }

    if (conf->upstream.cache_methods == 0) {
        conf->upstream.cache_methods = prev->upstream.cache_methods;
    }

    conf->upstream.cache_methods |= NGX_HTTP_GET|NGX_HTTP_HEAD;

    ngx_conf_merge_ptr_value(conf->upstream.cache_bypass,
                             prev->upstream.cache_bypass, NULL);

    ngx_conf_merge_ptr_value(conf->upstream.no_cache,
                             prev->upstream.no_cache, NULL);

    ngx_conf_merge_ptr_value(conf->upstream.cache_valid,
                             prev->upstream.cache_valid, NULL);

    if (conf->cache_key.value.data == NULL) {
        conf->cache_key = prev->cache_key;
    }

#endif

    ngx_conf_merge_value(conf->upstream.pass_request_headers,
                         prev->upstream.pass_request_headers, 1);
    ngx_conf_merge_value(conf->upstream.pass_request_body,
                         prev->upstream.pass_request_body, 1);

    ngx_conf_merge_value(conf->upstream.intercept_errors,
                         prev->upstream.intercept_errors, 0);

    hash.max_size = 512;
    hash.bucket_size = ngx_align(64, ngx_cacheline_size);
    hash.name = "scgi_hide_headers_hash";

    if (ngx_http_upstream_hide_headers_hash(cf, &conf->upstream,
            &prev->upstream, ngx_http_scgi_hide_headers, &hash)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    if (conf->upstream.upstream == NULL) {
        conf->upstream.upstream = prev->upstream.upstream;
    }

    if (conf->scgi_lengths == NULL) {
        conf->scgi_lengths = prev->scgi_lengths;
        conf->scgi_values = prev->scgi_values;
    }

    if (conf->upstream.upstream || conf->scgi_lengths) {
        clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
        if (clcf->handler == NULL && clcf->lmt_excpt) {
            clcf->handler = ngx_http_scgi_handler;
        }
    }

    if (conf->params_source == NULL) {
        conf->flushes = prev->flushes;
        conf->params_len = prev->params_len;
        conf->params = prev->params;
        conf->params_source = prev->params_source;
        conf->headers_hash = prev->headers_hash;

#if (NGX_HTTP_CACHE)

        if (conf->params_source == NULL) {

            if ((conf->upstream.cache == NULL)
                == (prev->upstream.cache == NULL))
            {
                return NGX_CONF_OK;
            }

            /* 6 is a number of ngx_http_scgi_cache_headers entries */
            conf->params_source = ngx_array_create(cf->pool, 6,
                                                   sizeof(ngx_keyval_t));
            if (conf->params_source == NULL) {
                return NGX_CONF_ERROR;
            }
        }
#else

        if (conf->params_source == NULL) {
            return NGX_CONF_OK;
        }

#endif
    }

    conf->params_len = ngx_array_create(cf->pool, 64, 1);
    if (conf->params_len == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->params = ngx_array_create(cf->pool, 512, 1);
    if (conf->params == NULL) {
        return NGX_CONF_ERROR;
    }

    if (ngx_array_init(&headers_names, cf->temp_pool, 4, sizeof(ngx_hash_key_t))
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    src = conf->params_source->elts;

#if (NGX_HTTP_CACHE)

    if (conf->upstream.cache) {
        ngx_keyval_t  *h, *s;

        for (h = ngx_http_scgi_cache_headers; h->key.len; h++) {

            for (i = 0; i < conf->params_source->nelts; i++) {
                if (ngx_strcasecmp(h->key.data, src[i].key.data) == 0) {
                    goto next;
                }
            }

            s = ngx_array_push(conf->params_source);
            if (s == NULL) {
                return NGX_CONF_ERROR;
            }

            *s = *h;

            src = conf->params_source->elts;

        next:

            h++;
        }
    }

#endif

    for (i = 0; i < conf->params_source->nelts; i++) {

        if (src[i].key.len > sizeof("HTTP_") - 1
            && ngx_strncmp(src[i].key.data, "HTTP_", sizeof("HTTP_") - 1) == 0)
        {
            hk = ngx_array_push(&headers_names);
            if (hk == NULL) {
                return NGX_CONF_ERROR;
            }

            hk->key.len = src[i].key.len - 5;
            hk->key.data = src[i].key.data + 5;
            hk->key_hash = ngx_hash_key_lc(hk->key.data, hk->key.len);
            hk->value = (void *) 1;

            if (src[i].value.len == 0) {
                continue;
            }
        }

        copy = ngx_array_push_n(conf->params_len,
                                sizeof(ngx_http_script_copy_code_t));
        if (copy == NULL) {
            return NGX_CONF_ERROR;
        }

        copy->code = (ngx_http_script_code_pt) ngx_http_script_copy_len_code;
        copy->len = src[i].key.len + 1;


        size = (sizeof(ngx_http_script_copy_code_t)
                + src[i].key.len + 1 + sizeof(uintptr_t) - 1)
               & ~(sizeof(uintptr_t) - 1);

        copy = ngx_array_push_n(conf->params, size);
        if (copy == NULL) {
            return NGX_CONF_ERROR;
        }

        copy->code = ngx_http_script_copy_code;
        copy->len = src[i].key.len + 1;

        p = (u_char *) copy + sizeof(ngx_http_script_copy_code_t);
        (void) ngx_cpystrn(p, src[i].key.data, src[i].key.len + 1);


        ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

        sc.cf = cf;
        sc.source = &src[i].value;
        sc.flushes = &conf->flushes;
        sc.lengths = &conf->params_len;
        sc.values = &conf->params;

        if (ngx_http_script_compile(&sc) != NGX_OK) {
            return NGX_CONF_ERROR;
        }

        code = ngx_array_push_n(conf->params_len, sizeof(uintptr_t));
        if (code == NULL) {
            return NGX_CONF_ERROR;
        }

        *code = (uintptr_t) NULL;


        code = ngx_array_push_n(conf->params, sizeof(uintptr_t));
        if (code == NULL) {
            return NGX_CONF_ERROR;
        }

        *code = (uintptr_t) NULL;
    }

    code = ngx_array_push_n(conf->params_len, sizeof(uintptr_t));
    if (code == NULL) {
        return NGX_CONF_ERROR;
    }

    *code = (uintptr_t) NULL;

    code = ngx_array_push_n(conf->params, sizeof(uintptr_t));
    if (code == NULL) {
        return NGX_CONF_ERROR;
    }

    *code = (uintptr_t) NULL;

    conf->header_params = headers_names.nelts;

    hash.hash = &conf->headers_hash;
    hash.key = ngx_hash_key_lc;
    hash.max_size = 512;
    hash.bucket_size = 64;
    hash.name = "scgi_params_hash";
    hash.pool = cf->pool;
    hash.temp_pool = NULL;

    if (ngx_hash_init(&hash, headers_names.elts, headers_names.nelts) != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_scgi_pass(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_scgi_loc_conf_t *scf = conf;

    ngx_url_t                   u;
    ngx_str_t                  *value, *url;
    ngx_uint_t                  n;
    ngx_http_core_loc_conf_t   *clcf;
    ngx_http_script_compile_t   sc;

    if (scf->upstream.upstream || scf->scgi_lengths) {
        return "is duplicate";
    }

    clcf = ngx_http_conf_get_module_loc_conf (cf, ngx_http_core_module);
    clcf->handler = ngx_http_scgi_handler;

    value = cf->args->elts;

    url = &value[1];

    n = ngx_http_script_variables_count(url);

    if (n) {

        ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

        sc.cf = cf;
        sc.source = url;
        sc.lengths = &scf->scgi_lengths;
        sc.values = &scf->scgi_values;
        sc.variables = n;
        sc.complete_lengths = 1;
        sc.complete_values = 1;

        if (ngx_http_script_compile(&sc) != NGX_OK) {
            return NGX_CONF_ERROR;
        }

        return NGX_CONF_OK;
    }

    ngx_memzero(&u, sizeof(ngx_url_t));

    u.url = value[1];
    u.no_resolve = 1;

    scf->upstream.upstream = ngx_http_upstream_add(cf, &u, 0);
    if (scf->upstream.upstream == NULL) {
        return NGX_CONF_ERROR;
    }

    if (clcf->name.data[clcf->name.len - 1] == '/') {
        clcf->auto_redirect = 1;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_scgi_store(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_scgi_loc_conf_t *scf = conf;

    ngx_str_t                  *value;
    ngx_http_script_compile_t   sc;

    if (scf->upstream.store != NGX_CONF_UNSET || scf->upstream.store_lengths) {
        return "is duplicate";
    }

    value = cf->args->elts;

    if (ngx_strcmp(value[1].data, "off") == 0) {
        scf->upstream.store = 0;
        return NGX_CONF_OK;
    }

#if (NGX_HTTP_CACHE)

    if (scf->upstream.cache != NGX_CONF_UNSET_PTR
        && scf->upstream.cache != NULL)
    {
        return "is incompatible with \"scgi_cache\"";
    }

#endif

    if (ngx_strcmp(value[1].data, "on") == 0) {
        scf->upstream.store = 1;
        return NGX_CONF_OK;
    }

    /* include the terminating '\0' into script */
    value[1].len++;

    ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

    sc.cf = cf;
    sc.source = &value[1];
    sc.lengths = &scf->upstream.store_lengths;
    sc.values = &scf->upstream.store_values;
    sc.variables = ngx_http_script_variables_count(&value[1]);;
    sc.complete_lengths = 1;
    sc.complete_values = 1;

    if (ngx_http_script_compile(&sc) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


#if (NGX_HTTP_CACHE)

static char *
ngx_http_scgi_cache(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_scgi_loc_conf_t *scf = conf;

    ngx_str_t  *value;

    value = cf->args->elts;

    if (scf->upstream.cache != NGX_CONF_UNSET_PTR) {
        return "is duplicate";
    }

    if (ngx_strcmp(value[1].data, "off") == 0) {
        scf->upstream.cache = NULL;
        return NGX_CONF_OK;
    }

    if (scf->upstream.store > 0 || scf->upstream.store_lengths) {
        return "is incompatible with \"scgi_store\"";
    }

    scf->upstream.cache = ngx_shared_memory_add(cf, &value[1], 0,
                                                &ngx_http_scgi_module);
    if (scf->upstream.cache == NULL) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_scgi_cache_key(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_scgi_loc_conf_t *scf = conf;

    ngx_str_t                         *value;
    ngx_http_compile_complex_value_t   ccv;

    value = cf->args->elts;

    if (scf->cache_key.value.len) {
        return "is duplicate";
    }

    ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));

    ccv.cf = cf;
    ccv.value = &value[1];
    ccv.complex_value = &scf->cache_key;

    if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}

#endif