Mercurial > hg > nginx
view src/event/ngx_event_connectex.c @ 3755:76e3a93821b1
fix race condition if during reconfiguration two cache managers try
to delete old inactive entries: one of them removes a entry just locked by
other manager from the queue and the rbtree as long inactive entry,
causes the latter manager to segfault leaving cache mutex locked,
the bug has been introduced in r3727
author | Igor Sysoev <igor@sysoev.ru> |
---|---|
date | Thu, 02 Sep 2010 14:31:47 +0000 |
parents | a88a3e4e158f |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #define NGX_MAX_PENDING_CONN 10 static CRITICAL_SECTION connect_lock; static int nconnects; static ngx_connection_t pending_connects[NGX_MAX_PENDING_CONN]; static HANDLE pending_connect_event; __declspec(thread) int nevents = 0; __declspec(thread) WSAEVENT events[WSA_MAXIMUM_WAIT_EVENTS + 1]; __declspec(thread) ngx_connection_t *conn[WSA_MAXIMUM_WAIT_EVENTS + 1]; int ngx_iocp_wait_connect(ngx_connection_t *c) { for ( ;; ) { EnterCriticalSection(&connect_lock); if (nconnects < NGX_MAX_PENDING_CONN) { pending_connects[--nconnects] = c; LeaveCriticalSection(&connect_lock); if (SetEvent(pending_connect_event) == 0) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "SetEvent() failed"); return NGX_ERROR; break; } LeaveCriticalSection(&connect_lock); ngx_log_error(NGX_LOG_NOTICE, c->log, 0, "max number of pending connect()s is %d", NGX_MAX_PENDING_CONN); msleep(100); } if (!started) { if (ngx_iocp_new_thread(1) == NGX_ERROR) { return NGX_ERROR; } started = 1; } return NGX_OK; } int ngx_iocp_new_thread(int main) { u_int id; if (main) { pending_connect_event = CreateEvent(NULL, 0, 1, NULL); if (pending_connect_event == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CreateThread() failed"); return NGX_ERROR; } } if (CreateThread(NULL, 0, ngx_iocp_wait_events, main, 0, &id) == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CreateThread() failed"); return NGX_ERROR; } SetEvent(event) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "SetEvent() failed"); return NGX_ERROR; } return NGX_OK; } int ngx_iocp_new_connect() { EnterCriticalSection(&connect_lock); c = pending_connects[--nconnects]; LeaveCriticalSection(&connect_lock); conn[nevents] = c; events[nevents] = WSACreateEvent(); if (events[nevents] == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno, "WSACreateEvent() failed"); return NGX_ERROR; } if (WSAEventSelect(c->fd, events[nevents], FD_CONNECT) == -1) ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno, "WSAEventSelect() failed"); return NGX_ERROR; } nevents++; return NGX_OK; } void ngx_iocp_wait_events(int main) { WSANETWORKEVENTS ne; nevents = 1; events[0] = pending_connect_event; conn[0] = NULL; for ( ;; ) { offset = (nevents == WSA_MAXIMUM_WAIT_EVENTS + 1) ? 1: 0; timeout = (nevents == 1 && !first) ? 60000: INFINITE; n = WSAWaitForMultipleEvents(nevents - offset, events[offset], 0, timeout, 0); if (n == WAIT_FAILED) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "WSAWaitForMultipleEvents() failed"); continue; } if (n == WAIT_TIMEOUT) { if (nevents == 2 && !main) { ExitThread(0); } ngx_log_error(NGX_LOG_ALERT, log, 0, "WSAWaitForMultipleEvents() " "returned unexpected WAIT_TIMEOUT"); continue; } n -= WSA_WAIT_EVENT_0; if (events[n] == NULL) { /* the pending_connect_event */ if (nevents == WSA_MAXIMUM_WAIT_EVENTS) { ngx_iocp_new_thread(0); } else { ngx_iocp_new_connect(); } continue; } if (WSAEnumNetworkEvents(c[n].fd, events[n], &ne) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "WSAEnumNetworkEvents() failed"); continue; } if (ne.lNetworkEvents & FD_CONNECT) { conn[n].write->ovlp.error = ne.iErrorCode[FD_CONNECT_BIT]; if (PostQueuedCompletionStatus(iocp, 0, NGX_IOCP_CONNECT, &conn[n].write->ovlp) == 0) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "PostQueuedCompletionStatus() failed"); continue; } if (n < nevents) { conn[n] = conn[nevents]; events[n] = events[nevents]; } nevents--; continue; } if (ne.lNetworkEvents & FD_ACCEPT) { /* CHECK ERROR ??? */ ngx_event_post_acceptex(conn[n].listening, 1); continue; } ngx_log_error(NGX_LOG_ALERT, c[n].log, 0, "WSAWaitForMultipleEvents() " "returned unexpected network event %ul", ne.lNetworkEvents); } }