Mercurial > hg > nginx
view src/core/ngx_thread_pool.c @ 9300:5be23505292b
SSI: fixed incorrect or duplicate stub output.
Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set
if there are data in the first buffer sent in the subrequest. As a
result, following the change mentioned this flag cannot be used to
prevent duplicate ngx_http_ssi_stub_output() calls, since it is not
set if there was already some output, but the first buffer was empty.
Still, when there are multiple subrequests, even an empty subrequest
response might be delayed by the postpone filter, leading to a second
call of ngx_http_ssi_stub_output() during finalization from
ngx_http_writer() the subreqest buffers are released by the postpone
filter. Since r->request_output is not set after the first call, this
resulted in duplicate stub output.
Additionally, checking only the first buffer might be wrong in some
unusual cases. For example, the first buffer might be empty if
$r->flush() is called before printing any data in the embedded Perl
module.
Depending on the postpone_output value and corresponding sizes, this
issue can result in either duplicate or unexpected stub output, or
"zero size buf in writer" alerts.
Following 8124:f5515e727656 (1.23.4), it became slightly easier to
reproduce the issue, as empty static files and empty cache items now
result in a response with an empty buffer. Before the change, an empty
proxied response can be used to reproduce the issue.
Fix is check all buffers and set r->request_output if any non-empty
buffers are sent. This ensures that all unusual cases of non-empty
responses are covered, and also that r->request_output will be set
after the first stub output, preventing duplicate output.
Reported by Jan Gassen.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 04 Jul 2024 17:41:28 +0300 |
parents | 33d075b9097d |
children |
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/* * Copyright (C) Nginx, Inc. * Copyright (C) Valentin V. Bartenev * Copyright (C) Ruslan Ermilov */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_thread_pool.h> typedef struct { ngx_array_t pools; } ngx_thread_pool_conf_t; typedef struct { ngx_thread_task_t *first; ngx_thread_task_t **last; } ngx_thread_pool_queue_t; #define ngx_thread_pool_queue_init(q) \ (q)->first = NULL; \ (q)->last = &(q)->first struct ngx_thread_pool_s { ngx_thread_mutex_t mtx; ngx_thread_pool_queue_t queue; ngx_int_t waiting; ngx_thread_cond_t cond; ngx_log_t *log; ngx_str_t name; ngx_uint_t threads; ngx_int_t max_queue; u_char *file; ngx_uint_t line; }; static ngx_int_t ngx_thread_pool_init(ngx_thread_pool_t *tp, ngx_log_t *log, ngx_pool_t *pool); static void ngx_thread_pool_destroy(ngx_thread_pool_t *tp); static void ngx_thread_pool_exit_handler(void *data, ngx_log_t *log); static void *ngx_thread_pool_cycle(void *data); static void ngx_thread_pool_handler(ngx_event_t *ev); static char *ngx_thread_pool(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static void *ngx_thread_pool_create_conf(ngx_cycle_t *cycle); static char *ngx_thread_pool_init_conf(ngx_cycle_t *cycle, void *conf); static ngx_int_t ngx_thread_pool_init_worker(ngx_cycle_t *cycle); static void ngx_thread_pool_exit_worker(ngx_cycle_t *cycle); static ngx_command_t ngx_thread_pool_commands[] = { { ngx_string("thread_pool"), NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE23, ngx_thread_pool, 0, 0, NULL }, ngx_null_command }; static ngx_core_module_t ngx_thread_pool_module_ctx = { ngx_string("thread_pool"), ngx_thread_pool_create_conf, ngx_thread_pool_init_conf }; ngx_module_t ngx_thread_pool_module = { NGX_MODULE_V1, &ngx_thread_pool_module_ctx, /* module context */ ngx_thread_pool_commands, /* module directives */ NGX_CORE_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ ngx_thread_pool_init_worker, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ ngx_thread_pool_exit_worker, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_str_t ngx_thread_pool_default = ngx_string("default"); static ngx_uint_t ngx_thread_pool_task_id; static ngx_atomic_t ngx_thread_pool_done_lock; static ngx_thread_pool_queue_t ngx_thread_pool_done; static ngx_int_t ngx_thread_pool_init(ngx_thread_pool_t *tp, ngx_log_t *log, ngx_pool_t *pool) { int err; pthread_t tid; ngx_uint_t n; pthread_attr_t attr; if (ngx_notify == NULL) { ngx_log_error(NGX_LOG_ALERT, log, 0, "the configured event method cannot be used with thread pools"); return NGX_ERROR; } ngx_thread_pool_queue_init(&tp->queue); if (ngx_thread_mutex_create(&tp->mtx, log) != NGX_OK) { return NGX_ERROR; } if (ngx_thread_cond_create(&tp->cond, log) != NGX_OK) { (void) ngx_thread_mutex_destroy(&tp->mtx, log); return NGX_ERROR; } tp->log = log; err = pthread_attr_init(&attr); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_attr_init() failed"); return NGX_ERROR; } err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_attr_setdetachstate() failed"); return NGX_ERROR; } #if 0 err = pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_attr_setstacksize() failed"); return NGX_ERROR; } #endif for (n = 0; n < tp->threads; n++) { err = pthread_create(&tid, &attr, ngx_thread_pool_cycle, tp); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_create() failed"); return NGX_ERROR; } } (void) pthread_attr_destroy(&attr); return NGX_OK; } static void ngx_thread_pool_destroy(ngx_thread_pool_t *tp) { ngx_uint_t n; ngx_thread_task_t task; volatile ngx_uint_t lock; ngx_memzero(&task, sizeof(ngx_thread_task_t)); task.handler = ngx_thread_pool_exit_handler; task.ctx = (void *) &lock; for (n = 0; n < tp->threads; n++) { lock = 1; if (ngx_thread_task_post(tp, &task) != NGX_OK) { return; } while (lock) { ngx_sched_yield(); } task.event.active = 0; } (void) ngx_thread_cond_destroy(&tp->cond, tp->log); (void) ngx_thread_mutex_destroy(&tp->mtx, tp->log); } static void ngx_thread_pool_exit_handler(void *data, ngx_log_t *log) { ngx_uint_t *lock = data; *lock = 0; pthread_exit(0); } ngx_thread_task_t * ngx_thread_task_alloc(ngx_pool_t *pool, size_t size) { ngx_thread_task_t *task; task = ngx_pcalloc(pool, sizeof(ngx_thread_task_t) + size); if (task == NULL) { return NULL; } task->ctx = task + 1; return task; } ngx_int_t ngx_thread_task_post(ngx_thread_pool_t *tp, ngx_thread_task_t *task) { if (task->event.active) { ngx_log_error(NGX_LOG_ALERT, tp->log, 0, "task #%ui already active", task->id); return NGX_ERROR; } if (ngx_thread_mutex_lock(&tp->mtx, tp->log) != NGX_OK) { return NGX_ERROR; } if (tp->waiting >= tp->max_queue) { (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); ngx_log_error(NGX_LOG_ERR, tp->log, 0, "thread pool \"%V\" queue overflow: %i tasks waiting", &tp->name, tp->waiting); return NGX_ERROR; } task->event.active = 1; task->id = ngx_thread_pool_task_id++; task->next = NULL; if (ngx_thread_cond_signal(&tp->cond, tp->log) != NGX_OK) { (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); return NGX_ERROR; } *tp->queue.last = task; tp->queue.last = &task->next; tp->waiting++; (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0, "task #%ui added to thread pool \"%V\"", task->id, &tp->name); return NGX_OK; } static void * ngx_thread_pool_cycle(void *data) { ngx_thread_pool_t *tp = data; int err; sigset_t set; ngx_thread_task_t *task; #if 0 ngx_time_update(); #endif ngx_log_debug1(NGX_LOG_DEBUG_CORE, tp->log, 0, "thread in pool \"%V\" started", &tp->name); sigfillset(&set); sigdelset(&set, SIGILL); sigdelset(&set, SIGFPE); sigdelset(&set, SIGSEGV); sigdelset(&set, SIGBUS); err = pthread_sigmask(SIG_BLOCK, &set, NULL); if (err) { ngx_log_error(NGX_LOG_ALERT, tp->log, err, "pthread_sigmask() failed"); return NULL; } for ( ;; ) { if (ngx_thread_mutex_lock(&tp->mtx, tp->log) != NGX_OK) { return NULL; } /* the number may become negative */ tp->waiting--; while (tp->queue.first == NULL) { if (ngx_thread_cond_wait(&tp->cond, &tp->mtx, tp->log) != NGX_OK) { (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); return NULL; } } task = tp->queue.first; tp->queue.first = task->next; if (tp->queue.first == NULL) { tp->queue.last = &tp->queue.first; } if (ngx_thread_mutex_unlock(&tp->mtx, tp->log) != NGX_OK) { return NULL; } #if 0 ngx_time_update(); #endif ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0, "run task #%ui in thread pool \"%V\"", task->id, &tp->name); task->handler(task->ctx, tp->log); ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0, "complete task #%ui in thread pool \"%V\"", task->id, &tp->name); task->next = NULL; ngx_spinlock(&ngx_thread_pool_done_lock, 1, 2048); *ngx_thread_pool_done.last = task; ngx_thread_pool_done.last = &task->next; ngx_memory_barrier(); ngx_unlock(&ngx_thread_pool_done_lock); (void) ngx_notify(ngx_thread_pool_handler); } } static void ngx_thread_pool_handler(ngx_event_t *ev) { ngx_event_t *event; ngx_thread_task_t *task; ngx_log_debug0(NGX_LOG_DEBUG_CORE, ev->log, 0, "thread pool handler"); ngx_spinlock(&ngx_thread_pool_done_lock, 1, 2048); task = ngx_thread_pool_done.first; ngx_thread_pool_done.first = NULL; ngx_thread_pool_done.last = &ngx_thread_pool_done.first; ngx_memory_barrier(); ngx_unlock(&ngx_thread_pool_done_lock); while (task) { ngx_log_debug1(NGX_LOG_DEBUG_CORE, ev->log, 0, "run completion handler for task #%ui", task->id); event = &task->event; task = task->next; event->complete = 1; event->active = 0; event->handler(event); } } static void * ngx_thread_pool_create_conf(ngx_cycle_t *cycle) { ngx_thread_pool_conf_t *tcf; tcf = ngx_pcalloc(cycle->pool, sizeof(ngx_thread_pool_conf_t)); if (tcf == NULL) { return NULL; } if (ngx_array_init(&tcf->pools, cycle->pool, 4, sizeof(ngx_thread_pool_t *)) != NGX_OK) { return NULL; } return tcf; } static char * ngx_thread_pool_init_conf(ngx_cycle_t *cycle, void *conf) { ngx_thread_pool_conf_t *tcf = conf; ngx_uint_t i; ngx_thread_pool_t **tpp; tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { if (tpp[i]->threads) { continue; } if (tpp[i]->name.len == ngx_thread_pool_default.len && ngx_strncmp(tpp[i]->name.data, ngx_thread_pool_default.data, ngx_thread_pool_default.len) == 0) { tpp[i]->threads = 32; tpp[i]->max_queue = 65536; continue; } ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "unknown thread pool \"%V\" in %s:%ui", &tpp[i]->name, tpp[i]->file, tpp[i]->line); return NGX_CONF_ERROR; } return NGX_CONF_OK; } static char * ngx_thread_pool(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_str_t *value; ngx_uint_t i; ngx_thread_pool_t *tp; value = cf->args->elts; tp = ngx_thread_pool_add(cf, &value[1]); if (tp == NULL) { return NGX_CONF_ERROR; } if (tp->threads) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate thread pool \"%V\"", &tp->name); return NGX_CONF_ERROR; } tp->max_queue = 65536; for (i = 2; i < cf->args->nelts; i++) { if (ngx_strncmp(value[i].data, "threads=", 8) == 0) { tp->threads = ngx_atoi(value[i].data + 8, value[i].len - 8); if (tp->threads == (ngx_uint_t) NGX_ERROR || tp->threads == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid threads value \"%V\"", &value[i]); return NGX_CONF_ERROR; } continue; } if (ngx_strncmp(value[i].data, "max_queue=", 10) == 0) { tp->max_queue = ngx_atoi(value[i].data + 10, value[i].len - 10); if (tp->max_queue == NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid max_queue value \"%V\"", &value[i]); return NGX_CONF_ERROR; } continue; } } if (tp->threads == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "\"%V\" must have \"threads\" parameter", &cmd->name); return NGX_CONF_ERROR; } return NGX_CONF_OK; } ngx_thread_pool_t * ngx_thread_pool_add(ngx_conf_t *cf, ngx_str_t *name) { ngx_thread_pool_t *tp, **tpp; ngx_thread_pool_conf_t *tcf; if (name == NULL) { name = &ngx_thread_pool_default; } tp = ngx_thread_pool_get(cf->cycle, name); if (tp) { return tp; } tp = ngx_pcalloc(cf->pool, sizeof(ngx_thread_pool_t)); if (tp == NULL) { return NULL; } tp->name = *name; tp->file = cf->conf_file->file.name.data; tp->line = cf->conf_file->line; tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cf->cycle->conf_ctx, ngx_thread_pool_module); tpp = ngx_array_push(&tcf->pools); if (tpp == NULL) { return NULL; } *tpp = tp; return tp; } ngx_thread_pool_t * ngx_thread_pool_get(ngx_cycle_t *cycle, ngx_str_t *name) { ngx_uint_t i; ngx_thread_pool_t **tpp; ngx_thread_pool_conf_t *tcf; tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_thread_pool_module); tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { if (tpp[i]->name.len == name->len && ngx_strncmp(tpp[i]->name.data, name->data, name->len) == 0) { return tpp[i]; } } return NULL; } static ngx_int_t ngx_thread_pool_init_worker(ngx_cycle_t *cycle) { ngx_uint_t i; ngx_thread_pool_t **tpp; ngx_thread_pool_conf_t *tcf; if (ngx_process != NGX_PROCESS_WORKER && ngx_process != NGX_PROCESS_SINGLE) { return NGX_OK; } tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_thread_pool_module); if (tcf == NULL) { return NGX_OK; } ngx_thread_pool_queue_init(&ngx_thread_pool_done); tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { if (ngx_thread_pool_init(tpp[i], cycle->log, cycle->pool) != NGX_OK) { return NGX_ERROR; } } return NGX_OK; } static void ngx_thread_pool_exit_worker(ngx_cycle_t *cycle) { ngx_uint_t i; ngx_thread_pool_t **tpp; ngx_thread_pool_conf_t *tcf; if (ngx_process != NGX_PROCESS_WORKER && ngx_process != NGX_PROCESS_SINGLE) { return; } tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_thread_pool_module); if (tcf == NULL) { return; } tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { ngx_thread_pool_destroy(tpp[i]); } }