Mercurial > hg > nginx
view src/event/modules/ngx_select_module.c @ 7446:9234e8d61aa0
Win32: detection of connect() errors in select().
On Windows, connect() errors are only reported via exceptfds descriptor set
from select(). Previously exceptfds was set to NULL, and connect() errors
were not detected at all, so connects to closed ports were waiting till
a timeout occurred.
Since ongoing connect() means that there will be a write event active,
except descriptor set is copied from the write one. While it is possible
to construct except descriptor set as a concatenation of both read and write
descriptor sets, this looks unneeded.
With this change, connect() errors are properly detected now when using
select(). Note well that it is not possible to detect connect() errors with
WSAPoll() (see https://daniel.haxx.se/blog/2012/10/10/wsapoll-is-broken/).
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 24 Jan 2019 22:00:44 +0300 |
parents | a72886067bbb |
children | efd71d49bde0 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> static ngx_int_t ngx_select_init(ngx_cycle_t *cycle, ngx_msec_t timer); static void ngx_select_done(ngx_cycle_t *cycle); static ngx_int_t ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_select_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags); static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle); static char *ngx_select_init_conf(ngx_cycle_t *cycle, void *conf); static fd_set master_read_fd_set; static fd_set master_write_fd_set; static fd_set work_read_fd_set; static fd_set work_write_fd_set; static ngx_int_t max_fd; static ngx_uint_t nevents; static ngx_event_t **event_index; static ngx_str_t select_name = ngx_string("select"); static ngx_event_module_t ngx_select_module_ctx = { &select_name, NULL, /* create configuration */ ngx_select_init_conf, /* init configuration */ { ngx_select_add_event, /* add an event */ ngx_select_del_event, /* delete an event */ ngx_select_add_event, /* enable an event */ ngx_select_del_event, /* disable an event */ NULL, /* add an connection */ NULL, /* delete an connection */ NULL, /* trigger a notify */ ngx_select_process_events, /* process the events */ ngx_select_init, /* init the events */ ngx_select_done /* done the events */ } }; ngx_module_t ngx_select_module = { NGX_MODULE_V1, &ngx_select_module_ctx, /* module context */ NULL, /* module directives */ NGX_EVENT_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_select_init(ngx_cycle_t *cycle, ngx_msec_t timer) { ngx_event_t **index; if (event_index == NULL) { FD_ZERO(&master_read_fd_set); FD_ZERO(&master_write_fd_set); nevents = 0; } if (ngx_process >= NGX_PROCESS_WORKER || cycle->old_cycle == NULL || cycle->old_cycle->connection_n < cycle->connection_n) { index = ngx_alloc(sizeof(ngx_event_t *) * 2 * cycle->connection_n, cycle->log); if (index == NULL) { return NGX_ERROR; } if (event_index) { ngx_memcpy(index, event_index, sizeof(ngx_event_t *) * nevents); ngx_free(event_index); } event_index = index; } ngx_io = ngx_os_io; ngx_event_actions = ngx_select_module_ctx.actions; ngx_event_flags = NGX_USE_LEVEL_EVENT; max_fd = -1; return NGX_OK; } static void ngx_select_done(ngx_cycle_t *cycle) { ngx_free(event_index); event_index = NULL; } static ngx_int_t ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_connection_t *c; c = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "select add event fd:%d ev:%i", c->fd, event); if (ev->index != NGX_INVALID_INDEX) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "select event fd:%d ev:%i is already set", c->fd, event); return NGX_OK; } if ((event == NGX_READ_EVENT && ev->write) || (event == NGX_WRITE_EVENT && !ev->write)) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "invalid select %s event fd:%d ev:%i", ev->write ? "write" : "read", c->fd, event); return NGX_ERROR; } if (event == NGX_READ_EVENT) { FD_SET(c->fd, &master_read_fd_set); } else if (event == NGX_WRITE_EVENT) { FD_SET(c->fd, &master_write_fd_set); } if (max_fd != -1 && max_fd < c->fd) { max_fd = c->fd; } ev->active = 1; event_index[nevents] = ev; ev->index = nevents; nevents++; return NGX_OK; } static ngx_int_t ngx_select_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_event_t *e; ngx_connection_t *c; c = ev->data; ev->active = 0; if (ev->index == NGX_INVALID_INDEX) { return NGX_OK; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "select del event fd:%d ev:%i", c->fd, event); if (event == NGX_READ_EVENT) { FD_CLR(c->fd, &master_read_fd_set); } else if (event == NGX_WRITE_EVENT) { FD_CLR(c->fd, &master_write_fd_set); } if (max_fd == c->fd) { max_fd = -1; } if (ev->index < --nevents) { e = event_index[nevents]; event_index[ev->index] = e; e->index = ev->index; } ev->index = NGX_INVALID_INDEX; return NGX_OK; } static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags) { int ready, nready; ngx_err_t err; ngx_uint_t i, found; ngx_event_t *ev; ngx_queue_t *queue; struct timeval tv, *tp; ngx_connection_t *c; if (max_fd == -1) { for (i = 0; i < nevents; i++) { c = event_index[i]->data; if (max_fd < c->fd) { max_fd = c->fd; } } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "change max_fd: %i", max_fd); } #if (NGX_DEBUG) if (cycle->log->log_level & NGX_LOG_DEBUG_ALL) { for (i = 0; i < nevents; i++) { ev = event_index[i]; c = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select event: fd:%d wr:%d", c->fd, ev->write); } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "max_fd: %i", max_fd); } #endif if (timer == NGX_TIMER_INFINITE) { tp = NULL; } else { tv.tv_sec = (long) (timer / 1000); tv.tv_usec = (long) ((timer % 1000) * 1000); tp = &tv; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select timer: %M", timer); work_read_fd_set = master_read_fd_set; work_write_fd_set = master_write_fd_set; ready = select(max_fd + 1, &work_read_fd_set, &work_write_fd_set, NULL, tp); err = (ready == -1) ? ngx_errno : 0; if (flags & NGX_UPDATE_TIME || ngx_event_timer_alarm) { ngx_time_update(); } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select ready %d", ready); if (err) { ngx_uint_t level; if (err == NGX_EINTR) { if (ngx_event_timer_alarm) { ngx_event_timer_alarm = 0; return NGX_OK; } level = NGX_LOG_INFO; } else { level = NGX_LOG_ALERT; } ngx_log_error(level, cycle->log, err, "select() failed"); if (err == NGX_EBADF) { ngx_select_repair_fd_sets(cycle); } return NGX_ERROR; } if (ready == 0) { if (timer != NGX_TIMER_INFINITE) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "select() returned no events without timeout"); return NGX_ERROR; } nready = 0; for (i = 0; i < nevents; i++) { ev = event_index[i]; c = ev->data; found = 0; if (ev->write) { if (FD_ISSET(c->fd, &work_write_fd_set)) { found = 1; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select write %d", c->fd); } } else { if (FD_ISSET(c->fd, &work_read_fd_set)) { found = 1; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select read %d", c->fd); } } if (found) { ev->ready = 1; queue = ev->accept ? &ngx_posted_accept_events : &ngx_posted_events; ngx_post_event(ev, queue); nready++; } } if (ready != nready) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "select ready != events: %d:%d", ready, nready); ngx_select_repair_fd_sets(cycle); } return NGX_OK; } static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle) { int n; socklen_t len; ngx_err_t err; ngx_socket_t s; for (s = 0; s <= max_fd; s++) { if (FD_ISSET(s, &master_read_fd_set) == 0) { continue; } len = sizeof(int); if (getsockopt(s, SOL_SOCKET, SO_TYPE, &n, &len) == -1) { err = ngx_socket_errno; ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "invalid descriptor #%d in read fd_set", s); FD_CLR(s, &master_read_fd_set); } } for (s = 0; s <= max_fd; s++) { if (FD_ISSET(s, &master_write_fd_set) == 0) { continue; } len = sizeof(int); if (getsockopt(s, SOL_SOCKET, SO_TYPE, &n, &len) == -1) { err = ngx_socket_errno; ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "invalid descriptor #%d in write fd_set", s); FD_CLR(s, &master_write_fd_set); } } max_fd = -1; } static char * ngx_select_init_conf(ngx_cycle_t *cycle, void *conf) { ngx_event_conf_t *ecf; ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module); if (ecf->use != ngx_select_module.ctx_index) { return NGX_CONF_OK; } /* disable warning: the default FD_SETSIZE is 1024U in FreeBSD 5.x */ if (cycle->connection_n > FD_SETSIZE) { ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "the maximum number of files " "supported by select() is %ud", FD_SETSIZE); return NGX_CONF_ERROR; } return NGX_CONF_OK; }