Mercurial > hg > nginx
view src/stream/ngx_stream_limit_conn_module.c @ 9270:3d455e37abf8
Core: PID file writing synchronization.
Now, ngx_daemon() does not call exit() in the parent process immediately,
but instead waits for the child process to signal it actually started (and
wrote the PID file if configured to). This ensures that the PID file
already exists when the parent process exits.
To make sure that signal handlers won't cause unexpected logging in the
parent process if the child process dies (for example, due to errors when
writing the PID file), ngx_init_signals() is moved to the child process.
This resolves "PID file ... not readable (yet?) after start" and "Failed
to parse PID from file..." errors as observed with systemd.
Note that the errors observed are considered to be a bug in systemd, which
isn't able to work properly with traditional Unix daemons. Still, the
workaround is implemented to make sure there will be no OS vendor patches
trying to address this.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 13 May 2024 06:13:22 +0300 |
parents | b45f052483b8 |
children |
line wrap: on
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_stream.h> #define NGX_STREAM_LIMIT_CONN_PASSED 1 #define NGX_STREAM_LIMIT_CONN_REJECTED 2 #define NGX_STREAM_LIMIT_CONN_REJECTED_DRY_RUN 3 typedef struct { u_char color; u_char len; u_short conn; u_char data[1]; } ngx_stream_limit_conn_node_t; typedef struct { ngx_shm_zone_t *shm_zone; ngx_rbtree_node_t *node; } ngx_stream_limit_conn_cleanup_t; typedef struct { ngx_rbtree_t rbtree; ngx_rbtree_node_t sentinel; } ngx_stream_limit_conn_shctx_t; typedef struct { ngx_stream_limit_conn_shctx_t *sh; ngx_slab_pool_t *shpool; ngx_stream_complex_value_t key; } ngx_stream_limit_conn_ctx_t; typedef struct { ngx_shm_zone_t *shm_zone; ngx_uint_t conn; } ngx_stream_limit_conn_limit_t; typedef struct { ngx_array_t limits; ngx_uint_t log_level; ngx_flag_t dry_run; } ngx_stream_limit_conn_conf_t; static ngx_rbtree_node_t *ngx_stream_limit_conn_lookup(ngx_rbtree_t *rbtree, ngx_str_t *key, uint32_t hash); static void ngx_stream_limit_conn_cleanup(void *data); static ngx_inline void ngx_stream_limit_conn_cleanup_all(ngx_pool_t *pool); static ngx_int_t ngx_stream_limit_conn_status_variable(ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data); static void *ngx_stream_limit_conn_create_conf(ngx_conf_t *cf); static char *ngx_stream_limit_conn_merge_conf(ngx_conf_t *cf, void *parent, void *child); static char *ngx_stream_limit_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_stream_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_int_t ngx_stream_limit_conn_add_variables(ngx_conf_t *cf); static ngx_int_t ngx_stream_limit_conn_init(ngx_conf_t *cf); static ngx_conf_enum_t ngx_stream_limit_conn_log_levels[] = { { ngx_string("info"), NGX_LOG_INFO }, { ngx_string("notice"), NGX_LOG_NOTICE }, { ngx_string("warn"), NGX_LOG_WARN }, { ngx_string("error"), NGX_LOG_ERR }, { ngx_null_string, 0 } }; static ngx_command_t ngx_stream_limit_conn_commands[] = { { ngx_string("limit_conn_zone"), NGX_STREAM_MAIN_CONF|NGX_CONF_TAKE2, ngx_stream_limit_conn_zone, 0, 0, NULL }, { ngx_string("limit_conn"), NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE2, ngx_stream_limit_conn, NGX_STREAM_SRV_CONF_OFFSET, 0, NULL }, { ngx_string("limit_conn_log_level"), NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1, ngx_conf_set_enum_slot, NGX_STREAM_SRV_CONF_OFFSET, offsetof(ngx_stream_limit_conn_conf_t, log_level), &ngx_stream_limit_conn_log_levels }, { ngx_string("limit_conn_dry_run"), NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_STREAM_SRV_CONF_OFFSET, offsetof(ngx_stream_limit_conn_conf_t, dry_run), NULL }, ngx_null_command }; static ngx_stream_module_t ngx_stream_limit_conn_module_ctx = { ngx_stream_limit_conn_add_variables, /* preconfiguration */ ngx_stream_limit_conn_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ ngx_stream_limit_conn_create_conf, /* create server configuration */ ngx_stream_limit_conn_merge_conf /* merge server configuration */ }; ngx_module_t ngx_stream_limit_conn_module = { NGX_MODULE_V1, &ngx_stream_limit_conn_module_ctx, /* module context */ ngx_stream_limit_conn_commands, /* module directives */ NGX_STREAM_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_stream_variable_t ngx_stream_limit_conn_vars[] = { { ngx_string("limit_conn_status"), NULL, ngx_stream_limit_conn_status_variable, 0, NGX_STREAM_VAR_NOCACHEABLE, 0 }, ngx_stream_null_variable }; static ngx_str_t ngx_stream_limit_conn_status[] = { ngx_string("PASSED"), ngx_string("REJECTED"), ngx_string("REJECTED_DRY_RUN") }; static ngx_int_t ngx_stream_limit_conn_handler(ngx_stream_session_t *s) { size_t n; uint32_t hash; ngx_str_t key; ngx_uint_t i; ngx_rbtree_node_t *node; ngx_pool_cleanup_t *cln; ngx_stream_limit_conn_ctx_t *ctx; ngx_stream_limit_conn_node_t *lc; ngx_stream_limit_conn_conf_t *lccf; ngx_stream_limit_conn_limit_t *limits; ngx_stream_limit_conn_cleanup_t *lccln; lccf = ngx_stream_get_module_srv_conf(s, ngx_stream_limit_conn_module); limits = lccf->limits.elts; for (i = 0; i < lccf->limits.nelts; i++) { ctx = limits[i].shm_zone->data; if (ngx_stream_complex_value(s, &ctx->key, &key) != NGX_OK) { return NGX_ERROR; } if (key.len == 0) { continue; } if (key.len > 255) { ngx_log_error(NGX_LOG_ERR, s->connection->log, 0, "the value of the \"%V\" key " "is more than 255 bytes: \"%V\"", &ctx->key.value, &key); continue; } s->limit_conn_status = NGX_STREAM_LIMIT_CONN_PASSED; hash = ngx_crc32_short(key.data, key.len); ngx_shmtx_lock(&ctx->shpool->mutex); node = ngx_stream_limit_conn_lookup(&ctx->sh->rbtree, &key, hash); if (node == NULL) { n = offsetof(ngx_rbtree_node_t, color) + offsetof(ngx_stream_limit_conn_node_t, data) + key.len; node = ngx_slab_alloc_locked(ctx->shpool, n); if (node == NULL) { ngx_shmtx_unlock(&ctx->shpool->mutex); ngx_stream_limit_conn_cleanup_all(s->connection->pool); if (lccf->dry_run) { s->limit_conn_status = NGX_STREAM_LIMIT_CONN_REJECTED_DRY_RUN; return NGX_DECLINED; } s->limit_conn_status = NGX_STREAM_LIMIT_CONN_REJECTED; return NGX_STREAM_SERVICE_UNAVAILABLE; } lc = (ngx_stream_limit_conn_node_t *) &node->color; node->key = hash; lc->len = (u_char) key.len; lc->conn = 1; ngx_memcpy(lc->data, key.data, key.len); ngx_rbtree_insert(&ctx->sh->rbtree, node); } else { lc = (ngx_stream_limit_conn_node_t *) &node->color; if ((ngx_uint_t) lc->conn >= limits[i].conn) { ngx_shmtx_unlock(&ctx->shpool->mutex); ngx_log_error(lccf->log_level, s->connection->log, 0, "limiting connections%s by zone \"%V\"", lccf->dry_run ? ", dry run," : "", &limits[i].shm_zone->shm.name); ngx_stream_limit_conn_cleanup_all(s->connection->pool); if (lccf->dry_run) { s->limit_conn_status = NGX_STREAM_LIMIT_CONN_REJECTED_DRY_RUN; return NGX_DECLINED; } s->limit_conn_status = NGX_STREAM_LIMIT_CONN_REJECTED; return NGX_STREAM_SERVICE_UNAVAILABLE; } lc->conn++; } ngx_log_debug2(NGX_LOG_DEBUG_STREAM, s->connection->log, 0, "limit conn: %08Xi %d", node->key, lc->conn); ngx_shmtx_unlock(&ctx->shpool->mutex); cln = ngx_pool_cleanup_add(s->connection->pool, sizeof(ngx_stream_limit_conn_cleanup_t)); if (cln == NULL) { return NGX_ERROR; } cln->handler = ngx_stream_limit_conn_cleanup; lccln = cln->data; lccln->shm_zone = limits[i].shm_zone; lccln->node = node; } return NGX_DECLINED; } static void ngx_stream_limit_conn_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_rbtree_node_t **p; ngx_stream_limit_conn_node_t *lcn, *lcnt; for ( ;; ) { if (node->key < temp->key) { p = &temp->left; } else if (node->key > temp->key) { p = &temp->right; } else { /* node->key == temp->key */ lcn = (ngx_stream_limit_conn_node_t *) &node->color; lcnt = (ngx_stream_limit_conn_node_t *) &temp->color; p = (ngx_memn2cmp(lcn->data, lcnt->data, lcn->len, lcnt->len) < 0) ? &temp->left : &temp->right; } if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } static ngx_rbtree_node_t * ngx_stream_limit_conn_lookup(ngx_rbtree_t *rbtree, ngx_str_t *key, uint32_t hash) { ngx_int_t rc; ngx_rbtree_node_t *node, *sentinel; ngx_stream_limit_conn_node_t *lcn; node = rbtree->root; sentinel = rbtree->sentinel; while (node != sentinel) { if (hash < node->key) { node = node->left; continue; } if (hash > node->key) { node = node->right; continue; } /* hash == node->key */ lcn = (ngx_stream_limit_conn_node_t *) &node->color; rc = ngx_memn2cmp(key->data, lcn->data, key->len, (size_t) lcn->len); if (rc == 0) { return node; } node = (rc < 0) ? node->left : node->right; } return NULL; } static void ngx_stream_limit_conn_cleanup(void *data) { ngx_stream_limit_conn_cleanup_t *lccln = data; ngx_rbtree_node_t *node; ngx_stream_limit_conn_ctx_t *ctx; ngx_stream_limit_conn_node_t *lc; ctx = lccln->shm_zone->data; node = lccln->node; lc = (ngx_stream_limit_conn_node_t *) &node->color; ngx_shmtx_lock(&ctx->shpool->mutex); ngx_log_debug2(NGX_LOG_DEBUG_STREAM, lccln->shm_zone->shm.log, 0, "limit conn cleanup: %08Xi %d", node->key, lc->conn); lc->conn--; if (lc->conn == 0) { ngx_rbtree_delete(&ctx->sh->rbtree, node); ngx_slab_free_locked(ctx->shpool, node); } ngx_shmtx_unlock(&ctx->shpool->mutex); } static ngx_inline void ngx_stream_limit_conn_cleanup_all(ngx_pool_t *pool) { ngx_pool_cleanup_t *cln; cln = pool->cleanup; while (cln && cln->handler == ngx_stream_limit_conn_cleanup) { ngx_stream_limit_conn_cleanup(cln->data); cln = cln->next; } pool->cleanup = cln; } static ngx_int_t ngx_stream_limit_conn_init_zone(ngx_shm_zone_t *shm_zone, void *data) { ngx_stream_limit_conn_ctx_t *octx = data; size_t len; ngx_stream_limit_conn_ctx_t *ctx; ctx = shm_zone->data; if (octx) { if (ctx->key.value.len != octx->key.value.len || ngx_strncmp(ctx->key.value.data, octx->key.value.data, ctx->key.value.len) != 0) { ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0, "limit_conn_zone \"%V\" uses the \"%V\" key " "while previously it used the \"%V\" key", &shm_zone->shm.name, &ctx->key.value, &octx->key.value); return NGX_ERROR; } ctx->sh = octx->sh; ctx->shpool = octx->shpool; return NGX_OK; } ctx->shpool = (ngx_slab_pool_t *) shm_zone->shm.addr; if (shm_zone->shm.exists) { ctx->sh = ctx->shpool->data; return NGX_OK; } ctx->sh = ngx_slab_alloc(ctx->shpool, sizeof(ngx_stream_limit_conn_shctx_t)); if (ctx->sh == NULL) { return NGX_ERROR; } ctx->shpool->data = ctx->sh; ngx_rbtree_init(&ctx->sh->rbtree, &ctx->sh->sentinel, ngx_stream_limit_conn_rbtree_insert_value); len = sizeof(" in limit_conn_zone \"\"") + shm_zone->shm.name.len; ctx->shpool->log_ctx = ngx_slab_alloc(ctx->shpool, len); if (ctx->shpool->log_ctx == NULL) { return NGX_ERROR; } ngx_sprintf(ctx->shpool->log_ctx, " in limit_conn_zone \"%V\"%Z", &shm_zone->shm.name); return NGX_OK; } static ngx_int_t ngx_stream_limit_conn_status_variable(ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data) { if (s->limit_conn_status == 0) { v->not_found = 1; return NGX_OK; } v->valid = 1; v->no_cacheable = 0; v->not_found = 0; v->len = ngx_stream_limit_conn_status[s->limit_conn_status - 1].len; v->data = ngx_stream_limit_conn_status[s->limit_conn_status - 1].data; return NGX_OK; } static void * ngx_stream_limit_conn_create_conf(ngx_conf_t *cf) { ngx_stream_limit_conn_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_stream_limit_conn_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->limits.elts = NULL; */ conf->log_level = NGX_CONF_UNSET_UINT; conf->dry_run = NGX_CONF_UNSET; return conf; } static char * ngx_stream_limit_conn_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_stream_limit_conn_conf_t *prev = parent; ngx_stream_limit_conn_conf_t *conf = child; if (conf->limits.elts == NULL) { conf->limits = prev->limits; } ngx_conf_merge_uint_value(conf->log_level, prev->log_level, NGX_LOG_ERR); ngx_conf_merge_value(conf->dry_run, prev->dry_run, 0); return NGX_CONF_OK; } static char * ngx_stream_limit_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { u_char *p; ssize_t size; ngx_str_t *value, name, s; ngx_uint_t i; ngx_shm_zone_t *shm_zone; ngx_stream_limit_conn_ctx_t *ctx; ngx_stream_compile_complex_value_t ccv; value = cf->args->elts; ctx = ngx_pcalloc(cf->pool, sizeof(ngx_stream_limit_conn_ctx_t)); if (ctx == NULL) { return NGX_CONF_ERROR; } ngx_memzero(&ccv, sizeof(ngx_stream_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &ctx->key; if (ngx_stream_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } size = 0; name.len = 0; for (i = 2; i < cf->args->nelts; i++) { if (ngx_strncmp(value[i].data, "zone=", 5) == 0) { name.data = value[i].data + 5; p = (u_char *) ngx_strchr(name.data, ':'); if (p == NULL) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid zone size \"%V\"", &value[i]); return NGX_CONF_ERROR; } name.len = p - name.data; s.data = p + 1; s.len = value[i].data + value[i].len - s.data; size = ngx_parse_size(&s); if (size == NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid zone size \"%V\"", &value[i]); return NGX_CONF_ERROR; } if (size < (ssize_t) (8 * ngx_pagesize)) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "zone \"%V\" is too small", &value[i]); return NGX_CONF_ERROR; } continue; } ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[i]); return NGX_CONF_ERROR; } if (name.len == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "\"%V\" must have \"zone\" parameter", &cmd->name); return NGX_CONF_ERROR; } shm_zone = ngx_shared_memory_add(cf, &name, size, &ngx_stream_limit_conn_module); if (shm_zone == NULL) { return NGX_CONF_ERROR; } if (shm_zone->data) { ctx = shm_zone->data; ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V \"%V\" is already bound to key \"%V\"", &cmd->name, &name, &ctx->key.value); return NGX_CONF_ERROR; } shm_zone->init = ngx_stream_limit_conn_init_zone; shm_zone->data = ctx; return NGX_CONF_OK; } static char * ngx_stream_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_shm_zone_t *shm_zone; ngx_stream_limit_conn_conf_t *lccf = conf; ngx_stream_limit_conn_limit_t *limit, *limits; ngx_str_t *value; ngx_int_t n; ngx_uint_t i; value = cf->args->elts; shm_zone = ngx_shared_memory_add(cf, &value[1], 0, &ngx_stream_limit_conn_module); if (shm_zone == NULL) { return NGX_CONF_ERROR; } limits = lccf->limits.elts; if (limits == NULL) { if (ngx_array_init(&lccf->limits, cf->pool, 1, sizeof(ngx_stream_limit_conn_limit_t)) != NGX_OK) { return NGX_CONF_ERROR; } } for (i = 0; i < lccf->limits.nelts; i++) { if (shm_zone == limits[i].shm_zone) { return "is duplicate"; } } n = ngx_atoi(value[2].data, value[2].len); if (n <= 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid number of connections \"%V\"", &value[2]); return NGX_CONF_ERROR; } if (n > 65535) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "connection limit must be less 65536"); return NGX_CONF_ERROR; } limit = ngx_array_push(&lccf->limits); if (limit == NULL) { return NGX_CONF_ERROR; } limit->conn = n; limit->shm_zone = shm_zone; return NGX_CONF_OK; } static ngx_int_t ngx_stream_limit_conn_add_variables(ngx_conf_t *cf) { ngx_stream_variable_t *var, *v; for (v = ngx_stream_limit_conn_vars; v->name.len; v++) { var = ngx_stream_add_variable(cf, &v->name, v->flags); if (var == NULL) { return NGX_ERROR; } var->get_handler = v->get_handler; var->data = v->data; } return NGX_OK; } static ngx_int_t ngx_stream_limit_conn_init(ngx_conf_t *cf) { ngx_stream_handler_pt *h; ngx_stream_core_main_conf_t *cmcf; cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module); h = ngx_array_push(&cmcf->phases[NGX_STREAM_PREACCESS_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_stream_limit_conn_handler; return NGX_OK; }