Mercurial > hg > nginx
view src/core/ngx_module.c @ 8045:aa28c802409f
Resolver: make TCP write timer event cancelable.
Similar to 70e65bf8dfd7, the change is made to ensure that the ability to
cancel resolver tasks is fully controlled by the caller. As mentioned in the
referenced commit, it is safe to make this timer cancelable because resolve
tasks can have their own timeouts that are not cancelable.
The scenario where this may become a problem is a periodic background resolve
task (not tied to a specific request or a client connection), which receives a
response with short TTL, large enough to warrant fallback to a TCP query.
With each event loop wakeup, we either have a previously set write timer
instance or schedule a new one. The non-cancelable write timer can delay or
block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable
flag is set by the API user, and there are no other tasks or connections.
We use the resolver API in this way to maintain the list of upstream server
addresses specified with the 'resolve' parameter, and there could be third-party
modules implementing similar logic.
author | Aleksei Bavshin <a.bavshin@f5.com> |
---|---|
date | Wed, 01 Jun 2022 20:17:23 -0700 |
parents | 3600bbfb43e3 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Maxim Dounin * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #define NGX_MAX_DYNAMIC_MODULES 128 static ngx_uint_t ngx_module_index(ngx_cycle_t *cycle); static ngx_uint_t ngx_module_ctx_index(ngx_cycle_t *cycle, ngx_uint_t type, ngx_uint_t index); ngx_uint_t ngx_max_module; static ngx_uint_t ngx_modules_n; ngx_int_t ngx_preinit_modules(void) { ngx_uint_t i; for (i = 0; ngx_modules[i]; i++) { ngx_modules[i]->index = i; ngx_modules[i]->name = ngx_module_names[i]; } ngx_modules_n = i; ngx_max_module = ngx_modules_n + NGX_MAX_DYNAMIC_MODULES; return NGX_OK; } ngx_int_t ngx_cycle_modules(ngx_cycle_t *cycle) { /* * create a list of modules to be used for this cycle, * copy static modules to it */ cycle->modules = ngx_pcalloc(cycle->pool, (ngx_max_module + 1) * sizeof(ngx_module_t *)); if (cycle->modules == NULL) { return NGX_ERROR; } ngx_memcpy(cycle->modules, ngx_modules, ngx_modules_n * sizeof(ngx_module_t *)); cycle->modules_n = ngx_modules_n; return NGX_OK; } ngx_int_t ngx_init_modules(ngx_cycle_t *cycle) { ngx_uint_t i; for (i = 0; cycle->modules[i]; i++) { if (cycle->modules[i]->init_module) { if (cycle->modules[i]->init_module(cycle) != NGX_OK) { return NGX_ERROR; } } } return NGX_OK; } ngx_int_t ngx_count_modules(ngx_cycle_t *cycle, ngx_uint_t type) { ngx_uint_t i, next, max; ngx_module_t *module; next = 0; max = 0; /* count appropriate modules, set up their indices */ for (i = 0; cycle->modules[i]; i++) { module = cycle->modules[i]; if (module->type != type) { continue; } if (module->ctx_index != NGX_MODULE_UNSET_INDEX) { /* if ctx_index was assigned, preserve it */ if (module->ctx_index > max) { max = module->ctx_index; } if (module->ctx_index == next) { next++; } continue; } /* search for some free index */ module->ctx_index = ngx_module_ctx_index(cycle, type, next); if (module->ctx_index > max) { max = module->ctx_index; } next = module->ctx_index + 1; } /* * make sure the number returned is big enough for previous * cycle as well, else there will be problems if the number * will be stored in a global variable (as it's used to be) * and we'll have to roll back to the previous cycle */ if (cycle->old_cycle && cycle->old_cycle->modules) { for (i = 0; cycle->old_cycle->modules[i]; i++) { module = cycle->old_cycle->modules[i]; if (module->type != type) { continue; } if (module->ctx_index > max) { max = module->ctx_index; } } } /* prevent loading of additional modules */ cycle->modules_used = 1; return max + 1; } ngx_int_t ngx_add_module(ngx_conf_t *cf, ngx_str_t *file, ngx_module_t *module, char **order) { void *rv; ngx_uint_t i, m, before; ngx_core_module_t *core_module; if (cf->cycle->modules_n >= ngx_max_module) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "too many modules loaded"); return NGX_ERROR; } if (module->version != nginx_version) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "module \"%V\" version %ui instead of %ui", file, module->version, (ngx_uint_t) nginx_version); return NGX_ERROR; } if (ngx_strcmp(module->signature, NGX_MODULE_SIGNATURE) != 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "module \"%V\" is not binary compatible", file); return NGX_ERROR; } for (m = 0; cf->cycle->modules[m]; m++) { if (ngx_strcmp(cf->cycle->modules[m]->name, module->name) == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "module \"%s\" is already loaded", module->name); return NGX_ERROR; } } /* * if the module wasn't previously loaded, assign an index */ if (module->index == NGX_MODULE_UNSET_INDEX) { module->index = ngx_module_index(cf->cycle); if (module->index >= ngx_max_module) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "too many modules loaded"); return NGX_ERROR; } } /* * put the module into the cycle->modules array */ before = cf->cycle->modules_n; if (order) { for (i = 0; order[i]; i++) { if (ngx_strcmp(order[i], module->name) == 0) { i++; break; } } for ( /* void */ ; order[i]; i++) { #if 0 ngx_log_debug2(NGX_LOG_DEBUG_CORE, cf->log, 0, "module: %s before %s", module->name, order[i]); #endif for (m = 0; m < before; m++) { if (ngx_strcmp(cf->cycle->modules[m]->name, order[i]) == 0) { ngx_log_debug3(NGX_LOG_DEBUG_CORE, cf->log, 0, "module: %s before %s:%i", module->name, order[i], m); before = m; break; } } } } /* put the module before modules[before] */ if (before != cf->cycle->modules_n) { ngx_memmove(&cf->cycle->modules[before + 1], &cf->cycle->modules[before], (cf->cycle->modules_n - before) * sizeof(ngx_module_t *)); } cf->cycle->modules[before] = module; cf->cycle->modules_n++; if (module->type == NGX_CORE_MODULE) { /* * we are smart enough to initialize core modules; * other modules are expected to be loaded before * initialization - e.g., http modules must be loaded * before http{} block */ core_module = module->ctx; if (core_module->create_conf) { rv = core_module->create_conf(cf->cycle); if (rv == NULL) { return NGX_ERROR; } cf->cycle->conf_ctx[module->index] = rv; } } return NGX_OK; } static ngx_uint_t ngx_module_index(ngx_cycle_t *cycle) { ngx_uint_t i, index; ngx_module_t *module; index = 0; again: /* find an unused index */ for (i = 0; cycle->modules[i]; i++) { module = cycle->modules[i]; if (module->index == index) { index++; goto again; } } /* check previous cycle */ if (cycle->old_cycle && cycle->old_cycle->modules) { for (i = 0; cycle->old_cycle->modules[i]; i++) { module = cycle->old_cycle->modules[i]; if (module->index == index) { index++; goto again; } } } return index; } static ngx_uint_t ngx_module_ctx_index(ngx_cycle_t *cycle, ngx_uint_t type, ngx_uint_t index) { ngx_uint_t i; ngx_module_t *module; again: /* find an unused ctx_index */ for (i = 0; cycle->modules[i]; i++) { module = cycle->modules[i]; if (module->type != type) { continue; } if (module->ctx_index == index) { index++; goto again; } } /* check previous cycle */ if (cycle->old_cycle && cycle->old_cycle->modules) { for (i = 0; cycle->old_cycle->modules[i]; i++) { module = cycle->old_cycle->modules[i]; if (module->type != type) { continue; } if (module->ctx_index == index) { index++; goto again; } } } return index; }