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view src/http/modules/ngx_http_empty_gif_module.c @ 6133:af7eba90645d
Win32: shared memory base addresses and remapping.
Two mechanisms are implemented to make it possible to store pointers
in shared memory on Windows, in particular on Windows Vista and later
versions with ASLR:
- The ngx_shm_remap() function added to allow remapping of a shared memory
zone to the address originally used for it in the master process. While
important, it doesn't solve the problem by itself as in many cases it's
not possible to use the address because of conflicts with other
allocations.
- We now create mappings at the same address in all processes by starting
mappings at predefined addresses normally unused by newborn processes.
These two mechanisms combined allow to use shared memory on Windows
almost without problems, including reloads.
Based on the patch by Sergey Brester:
http://mailman.nginx.org/pipermail/nginx-devel/2015-April/006836.html
| author | Maxim Dounin <mdounin@mdounin.ru> |
|---|---|
| date | Mon, 27 Apr 2015 18:25:42 +0300 |
| parents | d620f497c50f |
| children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static char *ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_empty_gif_commands[] = { { ngx_string("empty_gif"), NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS, ngx_http_empty_gif, 0, 0, NULL }, ngx_null_command }; /* the minimal single pixel transparent GIF, 43 bytes */ static u_char ngx_empty_gif[] = { 'G', 'I', 'F', '8', '9', 'a', /* header */ /* logical screen descriptor */ 0x01, 0x00, /* logical screen width */ 0x01, 0x00, /* logical screen height */ 0x80, /* global 1-bit color table */ 0x01, /* background color #1 */ 0x00, /* no aspect ratio */ /* global color table */ 0x00, 0x00, 0x00, /* #0: black */ 0xff, 0xff, 0xff, /* #1: white */ /* graphic control extension */ 0x21, /* extension introducer */ 0xf9, /* graphic control label */ 0x04, /* block size */ 0x01, /* transparent color is given, */ /* no disposal specified, */ /* user input is not expected */ 0x00, 0x00, /* delay time */ 0x01, /* transparent color #1 */ 0x00, /* block terminator */ /* image descriptor */ 0x2c, /* image separator */ 0x00, 0x00, /* image left position */ 0x00, 0x00, /* image top position */ 0x01, 0x00, /* image width */ 0x01, 0x00, /* image height */ 0x00, /* no local color table, no interlaced */ /* table based image data */ 0x02, /* LZW minimum code size, */ /* must be at least 2-bit */ 0x02, /* block size */ 0x4c, 0x01, /* compressed bytes 01_001_100, 0000000_1 */ /* 100: clear code */ /* 001: 1 */ /* 101: end of information code */ 0x00, /* block terminator */ 0x3B /* trailer */ }; static ngx_http_module_t ngx_http_empty_gif_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_empty_gif_module = { NGX_MODULE_V1, &ngx_http_empty_gif_module_ctx, /* module context */ ngx_http_empty_gif_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_gif_type = ngx_string("image/gif"); static ngx_int_t ngx_http_empty_gif_handler(ngx_http_request_t *r) { ngx_http_complex_value_t cv; if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { return NGX_HTTP_NOT_ALLOWED; } ngx_memzero(&cv, sizeof(ngx_http_complex_value_t)); cv.value.len = sizeof(ngx_empty_gif); cv.value.data = ngx_empty_gif; r->headers_out.last_modified_time = 23349600; return ngx_http_send_response(r, NGX_HTTP_OK, &ngx_http_gif_type, &cv); } static char * ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_core_loc_conf_t *clcf; clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module); clcf->handler = ngx_http_empty_gif_handler; return NGX_CONF_OK; }