From 5fd673807d3cbe09b68c7e2631184d929905949b Mon Sep 17 00:00:00 2001 From: Jeremy Harris Date: Sun, 6 Jun 2021 11:29:56 +0100 Subject: [PATCH] Compute select fd_set outside daemon loop --- src/src/daemon.c | 116 +++++++++++++++++++++++++---------------------- 1 file changed, 61 insertions(+), 55 deletions(-) diff --git a/src/src/daemon.c b/src/src/daemon.c index 4ee1a1148..7decc7223 100644 --- a/src/src/daemon.c +++ b/src/src/daemon.c @@ -462,14 +462,14 @@ if (pid == 0) (void)fcntl(dup_accept_socket, F_SETFD, fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC); - #ifdef SA_NOCLDWAIT +#ifdef SA_NOCLDWAIT act.sa_handler = SIG_IGN; sigemptyset(&(act.sa_mask)); act.sa_flags = SA_NOCLDWAIT; sigaction(SIGCHLD, &act, NULL); - #else +#else signal(SIGCHLD, SIG_IGN); - #endif +#endif signal(SIGTERM, SIG_DFL); signal(SIGINT, SIG_DFL); @@ -1296,6 +1296,15 @@ return FALSE; } + + +static void +add_listener_socket(int fd, fd_set * fds, int * fd_max) +{ +FD_SET(fd, fds); +if (fd > *fd_max) *fd_max = fd; +} + /************************************************* * Exim Daemon Mainline * *************************************************/ @@ -1322,10 +1331,11 @@ There are no arguments to this function, and it never returns. */ void daemon_go(void) { -struct passwd *pw; -int *listen_sockets = NULL; -int listen_socket_count = 0; -ip_address_item *addresses = NULL; +struct passwd * pw; +int * listen_sockets = NULL; +int listen_socket_count = 0, listen_fd_max = 0; +fd_set select_listen; +ip_address_item * addresses = NULL; time_t last_connection_time = (time_t)0; int local_queue_run_max = atoi(CS expand_string(queue_run_max)); @@ -1336,6 +1346,7 @@ debugging lines get the pid added. */ DEBUG(D_any|D_v) debug_selector |= D_pid; +FD_ZERO(&select_listen); if (f.inetd_wait_mode) { listen_socket_count = 1; @@ -1372,6 +1383,9 @@ if (f.inetd_wait_mode) if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on))) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s", strerror(errno)); + + FD_SET(3, &select_listen); + listen_fd_max = 3; } @@ -1382,11 +1396,11 @@ if (f.inetd_wait_mode || f.daemon_listen) for those OS for which this is necessary the first time it is called (in order to perform an "open" on the kernel memory file). */ - #ifdef LOAD_AVG_NEEDS_ROOT +#ifdef LOAD_AVG_NEEDS_ROOT if (queue_only_load >= 0 || smtp_load_reserve >= 0 || (deliver_queue_load_max >= 0 && deliver_drop_privilege)) (void)os_getloadavg(); - #endif +#endif } @@ -1760,8 +1774,8 @@ if (f.daemon_listen && !f.inetd_wait_mode) for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++) { BOOL wildcard; - ip_address_item *ipa2; - int af; + ip_address_item * ipa2; + int fd, af; if (Ustrchr(ipa->address, ':') != NULL) { @@ -1774,7 +1788,7 @@ if (f.daemon_listen && !f.inetd_wait_mode) wildcard = ipa->address[0] == 0; } - if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0) + if ((listen_sockets[sk] = fd = ip_socket(SOCK_STREAM, af)) < 0) { if (check_special_case(0, addresses, ipa, FALSE)) { @@ -1792,7 +1806,7 @@ if (f.daemon_listen && !f.inetd_wait_mode) #ifdef IPV6_V6ONLY if (af == AF_INET6 && wildcard && - setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on), + setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, CS (&on), sizeof(on)) < 0) log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard " "socket failed (%s): carrying on without it", strerror(errno)); @@ -1802,7 +1816,7 @@ if (f.daemon_listen && !f.inetd_wait_mode) is being handled. Without this, a connection will prevent reuse of the smtp port for listening. */ - if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR, + if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, US (&on), sizeof(on)) < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket " "failed when starting daemon: %s", strerror(errno)); @@ -1810,7 +1824,7 @@ if (f.daemon_listen && !f.inetd_wait_mode) /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to disable this because it breaks some broken clients. */ - if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY, + if (tcp_nodelay) setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, US (&on), sizeof(on)); /* Now bind the socket to the required port; if Exim is being restarted @@ -1829,12 +1843,12 @@ if (f.daemon_listen && !f.inetd_wait_mode) for(;;) { uschar *msg, *addr; - if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break; + if (ip_bind(fd, af, ipa->address, ipa->port) >= 0) break; if (check_special_case(errno, addresses, ipa, TRUE)) { DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 " "listen() success; EADDRINUSE ignored\n"); - (void)close(listen_sockets[sk]); + (void)close(fd); goto SKIP_SOCKET; } msg = US strerror(errno); @@ -1862,30 +1876,31 @@ if (f.daemon_listen && !f.inetd_wait_mode) else debug_printf("listening on %s port %d\n", ipa->address, ipa->port); + /* Start listening on the bound socket, establishing the maximum backlog of + connections that is allowed. On success, add to the set of sockets for select + and continue to the next address. */ + #if defined(TCP_FASTOPEN) && !defined(__APPLE__) if ( f.tcp_fastopen_ok - && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN, + && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN, &smtp_connect_backlog, sizeof(smtp_connect_backlog))) { DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno)); f.tcp_fastopen_ok = FALSE; } #endif - - /* Start listening on the bound socket, establishing the maximum backlog of - connections that is allowed. On success, continue to the next address. */ - - if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0) + if (listen(fd, smtp_connect_backlog) >= 0) { #if defined(TCP_FASTOPEN) && defined(__APPLE__) if ( f.tcp_fastopen_ok - && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN, - &on, sizeof(on))) + && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN, &on, sizeof(on))) { DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno)); f.tcp_fastopen_ok = FALSE; } #endif + + add_listener_socket(fd, &select_listen, &listen_fd_max); continue; } @@ -1903,7 +1918,7 @@ if (f.daemon_listen && !f.inetd_wait_mode) DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 " "listen() success; EADDRINUSE ignored\n"); - (void)close(listen_sockets[sk]); + (void)close(fd); /* Come here if there has been a problem with the socket which we are going to ignore. We remove the address from the chain, and back up the @@ -1951,7 +1966,19 @@ if (f.running_in_test_harness || write_pid) DEBUG(D_any) debug_printf("%s pid file %s: %s\n", (operation == PID_WRITE) ? "write" : "check", pid_file_path, strerror(errno)); } +/* Add ancillary sockets to the set for select */ + +#ifndef DISABLE_TLS +if (tls_watch_fd >= 0) + add_listener_socket(tls_watch_fd, &select_listen, &listen_fd_max); +#endif +if (daemon_notifier_fd >= 0) + add_listener_socket(daemon_notifier_fd, &select_listen, &listen_fd_max); + +listen_fd_max++; + /* Set up the handler for SIGHUP, which causes a restart of the daemon. */ + sighup_seen = FALSE; signal(SIGHUP, sighup_handler); @@ -2398,28 +2425,8 @@ for (;;) if (f.daemon_listen) { int lcount; - int max_socket = 0; BOOL select_failed = FALSE; - fd_set select_listen; - - FD_ZERO(&select_listen); -#ifndef DISABLE_TLS - if (tls_watch_fd >= 0) - { - FD_SET(tls_watch_fd, &select_listen); - if (tls_watch_fd > max_socket) max_socket = tls_watch_fd; - } -#endif - if (daemon_notifier_fd >= 0) - { - FD_SET(daemon_notifier_fd, &select_listen); - if (daemon_notifier_fd > max_socket) max_socket = daemon_notifier_fd; - } - for (int sk = 0; sk < listen_socket_count; sk++) - { - FD_SET(listen_sockets[sk], &select_listen); - if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk]; - } + fd_set fds = select_listen; DEBUG(D_any) debug_printf("Listening...\n"); @@ -2436,7 +2443,7 @@ for (;;) errno = EINTR; } else - lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen, + lcount = select(listen_fd_max, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, NULL); if (lcount < 0) @@ -2474,28 +2481,27 @@ for (;;) if (!select_failed) { #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT)) - if (tls_watch_fd >= 0 && FD_ISSET(tls_watch_fd, &select_listen)) + if (tls_watch_fd >= 0 && FD_ISSET(tls_watch_fd, &fds)) { - FD_CLR(tls_watch_fd, &select_listen); + FD_CLR(tls_watch_fd, &fds); tls_watch_trigger_time = time(NULL); /* Set up delayed event */ tls_watch_discard_event(tls_watch_fd); break; /* to top of daemon loop */ } #endif - if ( daemon_notifier_fd >= 0 - && FD_ISSET(daemon_notifier_fd, &select_listen)) + if (daemon_notifier_fd >= 0 && FD_ISSET(daemon_notifier_fd, &fds)) { - FD_CLR(daemon_notifier_fd, &select_listen); + FD_CLR(daemon_notifier_fd, &fds); sigalrm_seen = daemon_notification(); break; /* to top of daemon loop */ } for (int sk = 0; sk < listen_socket_count; sk++) - if (FD_ISSET(listen_sockets[sk], &select_listen)) + if (FD_ISSET(listen_sockets[sk], &fds)) { len = sizeof(accepted); accept_socket = accept(listen_sockets[sk], (struct sockaddr *)&accepted, &len); - FD_CLR(listen_sockets[sk], &select_listen); + FD_CLR(listen_sockets[sk], &fds); break; } } -- 2.30.2