Mercurial > hg > nginx
view src/http/modules/ngx_http_degradation_module.c @ 7507:ea05113adbdb
Range filter: fixed loss of incoming chain links.
Filters are not allowed to change incoming chain links, and should allocate
their own links if any modifications are needed. Nevertheless
ngx_http_range_singlepart_body() modified incoming chain links in some
cases, notably at the end of the requested range.
No problems caused by this are currently known, mostly because of
limited number of possible modifications and the position of the range
body filter in the filter chain. Though this behaviour is clearly incorrect
and tests demonstrate that it can at least cause some proxy buffers being
lost when using proxy_force_ranges, leading to less effective handling
of responses.
Fix is to always allocate new chain links in ngx_http_range_singlepart_body().
Links are explicitly freed to ensure constant memory usage with long-lived
requests.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 13 May 2019 22:44:02 +0300 |
parents | 67653855682e |
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> typedef struct { size_t sbrk_size; } ngx_http_degradation_main_conf_t; typedef struct { ngx_uint_t degrade; } ngx_http_degradation_loc_conf_t; static ngx_conf_enum_t ngx_http_degrade[] = { { ngx_string("204"), 204 }, { ngx_string("444"), 444 }, { ngx_null_string, 0 } }; static void *ngx_http_degradation_create_main_conf(ngx_conf_t *cf); static void *ngx_http_degradation_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static char *ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_int_t ngx_http_degradation_init(ngx_conf_t *cf); static ngx_command_t ngx_http_degradation_commands[] = { { ngx_string("degradation"), NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1, ngx_http_degradation, NGX_HTTP_MAIN_CONF_OFFSET, 0, NULL }, { ngx_string("degrade"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_enum_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_degradation_loc_conf_t, degrade), &ngx_http_degrade }, ngx_null_command }; static ngx_http_module_t ngx_http_degradation_module_ctx = { NULL, /* preconfiguration */ ngx_http_degradation_init, /* postconfiguration */ ngx_http_degradation_create_main_conf, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_degradation_create_loc_conf, /* create location configuration */ ngx_http_degradation_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_degradation_module = { NGX_MODULE_V1, &ngx_http_degradation_module_ctx, /* module context */ ngx_http_degradation_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_int_t ngx_http_degradation_handler(ngx_http_request_t *r) { ngx_http_degradation_loc_conf_t *dlcf; dlcf = ngx_http_get_module_loc_conf(r, ngx_http_degradation_module); if (dlcf->degrade && ngx_http_degraded(r)) { return dlcf->degrade; } return NGX_DECLINED; } ngx_uint_t ngx_http_degraded(ngx_http_request_t *r) { time_t now; ngx_uint_t log; static size_t sbrk_size; static time_t sbrk_time; ngx_http_degradation_main_conf_t *dmcf; dmcf = ngx_http_get_module_main_conf(r, ngx_http_degradation_module); if (dmcf->sbrk_size) { log = 0; now = ngx_time(); /* lock mutex */ if (now != sbrk_time) { /* * ELF/i386 is loaded at 0x08000000, 128M * ELF/amd64 is loaded at 0x00400000, 4M * * use a function address to subtract the loading address */ sbrk_size = (size_t) sbrk(0) - ((uintptr_t) ngx_palloc & ~0x3FFFFF); sbrk_time = now; log = 1; } /* unlock mutex */ if (sbrk_size >= dmcf->sbrk_size) { if (log) { ngx_log_error(NGX_LOG_NOTICE, r->connection->log, 0, "degradation sbrk:%uzM", sbrk_size / (1024 * 1024)); } return 1; } } return 0; } static void * ngx_http_degradation_create_main_conf(ngx_conf_t *cf) { ngx_http_degradation_main_conf_t *dmcf; dmcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_degradation_main_conf_t)); if (dmcf == NULL) { return NULL; } return dmcf; } static void * ngx_http_degradation_create_loc_conf(ngx_conf_t *cf) { ngx_http_degradation_loc_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_degradation_loc_conf_t)); if (conf == NULL) { return NULL; } conf->degrade = NGX_CONF_UNSET_UINT; return conf; } static char * ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_degradation_loc_conf_t *prev = parent; ngx_http_degradation_loc_conf_t *conf = child; ngx_conf_merge_uint_value(conf->degrade, prev->degrade, 0); return NGX_CONF_OK; } static char * ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_degradation_main_conf_t *dmcf = conf; ngx_str_t *value, s; value = cf->args->elts; if (ngx_strncmp(value[1].data, "sbrk=", 5) == 0) { s.len = value[1].len - 5; s.data = value[1].data + 5; dmcf->sbrk_size = ngx_parse_size(&s); if (dmcf->sbrk_size == (size_t) NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid sbrk size \"%V\"", &value[1]); return NGX_CONF_ERROR; } return NGX_CONF_OK; } ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[1]); return NGX_CONF_ERROR; } static ngx_int_t ngx_http_degradation_init(ngx_conf_t *cf) { ngx_http_handler_pt *h; ngx_http_core_main_conf_t *cmcf; cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_degradation_handler; return NGX_OK; }