diff options
Diffstat (limited to 'lib/isc/unix/app.c')
| -rw-r--r-- | lib/isc/unix/app.c | 684 |
1 files changed, 684 insertions, 0 deletions
diff --git a/lib/isc/unix/app.c b/lib/isc/unix/app.c new file mode 100644 index 0000000..660b438 --- /dev/null +++ b/lib/isc/unix/app.c @@ -0,0 +1,684 @@ +/* + * Copyright (C) 2004, 2005, 2007, 2008 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1999-2003 Internet Software Consortium. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +/* $Id: app.c,v 1.60 2008/10/15 03:41:17 marka Exp $ */ + +/*! \file */ + +#include <config.h> + +#include <sys/param.h> /* Openserver 5.0.6A and FD_SETSIZE */ +#include <sys/types.h> + +#include <stddef.h> +#include <stdlib.h> +#include <errno.h> +#include <unistd.h> +#include <signal.h> +#include <sys/time.h> +#ifdef HAVE_EPOLL +#include <sys/epoll.h> +#endif + +#include <isc/app.h> +#include <isc/boolean.h> +#include <isc/condition.h> +#include <isc/msgs.h> +#include <isc/mutex.h> +#include <isc/event.h> +#include <isc/platform.h> +#include <isc/strerror.h> +#include <isc/string.h> +#include <isc/task.h> +#include <isc/time.h> +#include <isc/util.h> + +#ifdef ISC_PLATFORM_USETHREADS +#include <pthread.h> +#else /* ISC_PLATFORM_USETHREADS */ +#include "../timer_p.h" +#include "../task_p.h" +#include "socket_p.h" +#endif /* ISC_PLATFORM_USETHREADS */ + +static isc_eventlist_t on_run; +static isc_mutex_t lock; +static isc_boolean_t shutdown_requested = ISC_FALSE; +static isc_boolean_t running = ISC_FALSE; +/*! + * We assume that 'want_shutdown' can be read and written atomically. + */ +static volatile isc_boolean_t want_shutdown = ISC_FALSE; +/* + * We assume that 'want_reload' can be read and written atomically. + */ +static volatile isc_boolean_t want_reload = ISC_FALSE; + +static isc_boolean_t blocked = ISC_FALSE; +#ifdef ISC_PLATFORM_USETHREADS +static pthread_t blockedthread; +#endif /* ISC_PLATFORM_USETHREADS */ + +#ifdef HAVE_LINUXTHREADS +/*! + * Linux has sigwait(), but it appears to prevent signal handlers from + * running, even if they're not in the set being waited for. This makes + * it impossible to get the default actions for SIGILL, SIGSEGV, etc. + * Instead of messing with it, we just use sigsuspend() instead. + */ +#undef HAVE_SIGWAIT +/*! + * We need to remember which thread is the main thread... + */ +static pthread_t main_thread; +#endif + +#ifndef HAVE_SIGWAIT +static void +exit_action(int arg) { + UNUSED(arg); + want_shutdown = ISC_TRUE; +} + +static void +reload_action(int arg) { + UNUSED(arg); + want_reload = ISC_TRUE; +} +#endif + +static isc_result_t +handle_signal(int sig, void (*handler)(int)) { + struct sigaction sa; + char strbuf[ISC_STRERRORSIZE]; + + memset(&sa, 0, sizeof(sa)); + sa.sa_handler = handler; + + if (sigfillset(&sa.sa_mask) != 0 || + sigaction(sig, &sa, NULL) < 0) { + isc__strerror(errno, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + isc_msgcat_get(isc_msgcat, ISC_MSGSET_APP, + ISC_MSG_SIGNALSETUP, + "handle_signal() %d setup: %s"), + sig, strbuf); + return (ISC_R_UNEXPECTED); + } + + return (ISC_R_SUCCESS); +} + +isc_result_t +isc_app_start(void) { + isc_result_t result; + int presult; + sigset_t sset; + char strbuf[ISC_STRERRORSIZE]; + + /* + * Start an ISC library application. + */ + +#ifdef NEED_PTHREAD_INIT + /* + * BSDI 3.1 seg faults in pthread_sigmask() if we don't do this. + */ + presult = pthread_init(); + if (presult != 0) { + isc__strerror(presult, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_start() pthread_init: %s", strbuf); + return (ISC_R_UNEXPECTED); + } +#endif + +#ifdef HAVE_LINUXTHREADS + main_thread = pthread_self(); +#endif + + result = isc_mutex_init(&lock); + if (result != ISC_R_SUCCESS) + return (result); + +#ifndef HAVE_SIGWAIT + /* + * Install do-nothing handlers for SIGINT and SIGTERM. + * + * We install them now because BSDI 3.1 won't block + * the default actions, regardless of what we do with + * pthread_sigmask(). + */ + result = handle_signal(SIGINT, exit_action); + if (result != ISC_R_SUCCESS) + return (result); + result = handle_signal(SIGTERM, exit_action); + if (result != ISC_R_SUCCESS) + return (result); +#endif + + /* + * Always ignore SIGPIPE. + */ + result = handle_signal(SIGPIPE, SIG_IGN); + if (result != ISC_R_SUCCESS) + return (result); + + /* + * On Solaris 2, delivery of a signal whose action is SIG_IGN + * will not cause sigwait() to return. We may have inherited + * unexpected actions for SIGHUP, SIGINT, and SIGTERM from our parent + * process (e.g, Solaris cron). Set an action of SIG_DFL to make + * sure sigwait() works as expected. Only do this for SIGTERM and + * SIGINT if we don't have sigwait(), since a different handler is + * installed above. + */ + result = handle_signal(SIGHUP, SIG_DFL); + if (result != ISC_R_SUCCESS) + return (result); + +#ifdef HAVE_SIGWAIT + result = handle_signal(SIGTERM, SIG_DFL); + if (result != ISC_R_SUCCESS) + return (result); + result = handle_signal(SIGINT, SIG_DFL); + if (result != ISC_R_SUCCESS) + return (result); +#endif + +#ifdef ISC_PLATFORM_USETHREADS + /* + * Block SIGHUP, SIGINT, SIGTERM. + * + * If isc_app_start() is called from the main thread before any other + * threads have been created, then the pthread_sigmask() call below + * will result in all threads having SIGHUP, SIGINT and SIGTERM + * blocked by default, ensuring that only the thread that calls + * sigwait() for them will get those signals. + */ + if (sigemptyset(&sset) != 0 || + sigaddset(&sset, SIGHUP) != 0 || + sigaddset(&sset, SIGINT) != 0 || + sigaddset(&sset, SIGTERM) != 0) { + isc__strerror(errno, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_start() sigsetops: %s", strbuf); + return (ISC_R_UNEXPECTED); + } + presult = pthread_sigmask(SIG_BLOCK, &sset, NULL); + if (presult != 0) { + isc__strerror(presult, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_start() pthread_sigmask: %s", + strbuf); + return (ISC_R_UNEXPECTED); + } +#else /* ISC_PLATFORM_USETHREADS */ + /* + * Unblock SIGHUP, SIGINT, SIGTERM. + * + * If we're not using threads, we need to make sure that SIGHUP, + * SIGINT and SIGTERM are not inherited as blocked from the parent + * process. + */ + if (sigemptyset(&sset) != 0 || + sigaddset(&sset, SIGHUP) != 0 || + sigaddset(&sset, SIGINT) != 0 || + sigaddset(&sset, SIGTERM) != 0) { + isc__strerror(errno, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_start() sigsetops: %s", strbuf); + return (ISC_R_UNEXPECTED); + } + presult = sigprocmask(SIG_UNBLOCK, &sset, NULL); + if (presult != 0) { + isc__strerror(presult, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_start() sigprocmask: %s", strbuf); + return (ISC_R_UNEXPECTED); + } +#endif /* ISC_PLATFORM_USETHREADS */ + + ISC_LIST_INIT(on_run); + + return (ISC_R_SUCCESS); +} + +isc_result_t +isc_app_onrun(isc_mem_t *mctx, isc_task_t *task, isc_taskaction_t action, + void *arg) +{ + isc_event_t *event; + isc_task_t *cloned_task = NULL; + isc_result_t result; + + LOCK(&lock); + + if (running) { + result = ISC_R_ALREADYRUNNING; + goto unlock; + } + + /* + * Note that we store the task to which we're going to send the event + * in the event's "sender" field. + */ + isc_task_attach(task, &cloned_task); + event = isc_event_allocate(mctx, cloned_task, ISC_APPEVENT_SHUTDOWN, + action, arg, sizeof(*event)); + if (event == NULL) { + result = ISC_R_NOMEMORY; + goto unlock; + } + + ISC_LIST_APPEND(on_run, event, ev_link); + + result = ISC_R_SUCCESS; + + unlock: + UNLOCK(&lock); + + return (result); +} + +#ifndef ISC_PLATFORM_USETHREADS +/*! + * Event loop for nonthreaded programs. + */ +static isc_result_t +evloop(void) { + isc_result_t result; + while (!want_shutdown) { + int n; + isc_time_t when, now; + struct timeval tv, *tvp; + isc_socketwait_t *swait; + isc_boolean_t readytasks; + isc_boolean_t call_timer_dispatch = ISC_FALSE; + + readytasks = isc__taskmgr_ready(); + if (readytasks) { + tv.tv_sec = 0; + tv.tv_usec = 0; + tvp = &tv; + call_timer_dispatch = ISC_TRUE; + } else { + result = isc__timermgr_nextevent(&when); + if (result != ISC_R_SUCCESS) + tvp = NULL; + else { + isc_uint64_t us; + + TIME_NOW(&now); + us = isc_time_microdiff(&when, &now); + if (us == 0) + call_timer_dispatch = ISC_TRUE; + tv.tv_sec = us / 1000000; + tv.tv_usec = us % 1000000; + tvp = &tv; + } + } + + swait = NULL; + n = isc__socketmgr_waitevents(tvp, &swait); + + if (n == 0 || call_timer_dispatch) { + /* + * We call isc__timermgr_dispatch() only when + * necessary, in order to reduce overhead. If the + * select() call indicates a timeout, we need the + * dispatch. Even if not, if we set the 0-timeout + * for the select() call, we need to check the timer + * events. In the 'readytasks' case, there may be no + * timeout event actually, but there is no other way + * to reduce the overhead. + * Note that we do not have to worry about the case + * where a new timer is inserted during the select() + * call, since this loop only runs in the non-thread + * mode. + */ + isc__timermgr_dispatch(); + } + if (n > 0) + (void)isc__socketmgr_dispatch(swait); + (void)isc__taskmgr_dispatch(); + + if (want_reload) { + want_reload = ISC_FALSE; + return (ISC_R_RELOAD); + } + } + return (ISC_R_SUCCESS); +} + +/* + * This is a gross hack to support waiting for condition + * variables in nonthreaded programs in a limited way; + * see lib/isc/nothreads/include/isc/condition.h. + * We implement isc_condition_wait() by entering the + * event loop recursively until the want_shutdown flag + * is set by isc_condition_signal(). + */ + +/*! + * \brief True if we are currently executing in the recursive + * event loop. + */ +static isc_boolean_t in_recursive_evloop = ISC_FALSE; + +/*! + * \brief True if we are exiting the event loop as the result of + * a call to isc_condition_signal() rather than a shutdown + * or reload. + */ +static isc_boolean_t signalled = ISC_FALSE; + +isc_result_t +isc__nothread_wait_hack(isc_condition_t *cp, isc_mutex_t *mp) { + isc_result_t result; + + UNUSED(cp); + UNUSED(mp); + + INSIST(!in_recursive_evloop); + in_recursive_evloop = ISC_TRUE; + + INSIST(*mp == 1); /* Mutex must be locked on entry. */ + --*mp; + + result = evloop(); + if (result == ISC_R_RELOAD) + want_reload = ISC_TRUE; + if (signalled) { + want_shutdown = ISC_FALSE; + signalled = ISC_FALSE; + } + + ++*mp; + in_recursive_evloop = ISC_FALSE; + return (ISC_R_SUCCESS); +} + +isc_result_t +isc__nothread_signal_hack(isc_condition_t *cp) { + + UNUSED(cp); + + INSIST(in_recursive_evloop); + + want_shutdown = ISC_TRUE; + signalled = ISC_TRUE; + return (ISC_R_SUCCESS); +} + +#endif /* ISC_PLATFORM_USETHREADS */ + +isc_result_t +isc_app_run(void) { + int result; + isc_event_t *event, *next_event; + isc_task_t *task; +#ifdef ISC_PLATFORM_USETHREADS + sigset_t sset; + char strbuf[ISC_STRERRORSIZE]; +#ifdef HAVE_SIGWAIT + int sig; +#endif +#endif /* ISC_PLATFORM_USETHREADS */ + +#ifdef HAVE_LINUXTHREADS + REQUIRE(main_thread == pthread_self()); +#endif + + LOCK(&lock); + + if (!running) { + running = ISC_TRUE; + + /* + * Post any on-run events (in FIFO order). + */ + for (event = ISC_LIST_HEAD(on_run); + event != NULL; + event = next_event) { + next_event = ISC_LIST_NEXT(event, ev_link); + ISC_LIST_UNLINK(on_run, event, ev_link); + task = event->ev_sender; + event->ev_sender = NULL; + isc_task_sendanddetach(&task, &event); + } + + } + + UNLOCK(&lock); + +#ifndef HAVE_SIGWAIT + /* + * Catch SIGHUP. + * + * We do this here to ensure that the signal handler is installed + * (i.e. that it wasn't a "one-shot" handler). + */ + result = handle_signal(SIGHUP, reload_action); + if (result != ISC_R_SUCCESS) + return (ISC_R_SUCCESS); +#endif + +#ifdef ISC_PLATFORM_USETHREADS + /* + * There is no danger if isc_app_shutdown() is called before we wait + * for signals. Signals are blocked, so any such signal will simply + * be made pending and we will get it when we call sigwait(). + */ + + while (!want_shutdown) { +#ifdef HAVE_SIGWAIT + /* + * Wait for SIGHUP, SIGINT, or SIGTERM. + */ + if (sigemptyset(&sset) != 0 || + sigaddset(&sset, SIGHUP) != 0 || + sigaddset(&sset, SIGINT) != 0 || + sigaddset(&sset, SIGTERM) != 0) { + isc__strerror(errno, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_run() sigsetops: %s", strbuf); + return (ISC_R_UNEXPECTED); + } + +#ifndef HAVE_UNIXWARE_SIGWAIT + result = sigwait(&sset, &sig); + if (result == 0) { + if (sig == SIGINT || + sig == SIGTERM) + want_shutdown = ISC_TRUE; + else if (sig == SIGHUP) + want_reload = ISC_TRUE; + } + +#else /* Using UnixWare sigwait semantics. */ + sig = sigwait(&sset); + if (sig >= 0) { + if (sig == SIGINT || + sig == SIGTERM) + want_shutdown = ISC_TRUE; + else if (sig == SIGHUP) + want_reload = ISC_TRUE; + } + +#endif /* HAVE_UNIXWARE_SIGWAIT */ +#else /* Don't have sigwait(). */ + /* + * Listen for all signals. + */ + if (sigemptyset(&sset) != 0) { + isc__strerror(errno, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_run() sigsetops: %s", strbuf); + return (ISC_R_UNEXPECTED); + } + result = sigsuspend(&sset); +#endif /* HAVE_SIGWAIT */ + + if (want_reload) { + want_reload = ISC_FALSE; + return (ISC_R_RELOAD); + } + + if (want_shutdown && blocked) + exit(1); + } + +#else /* ISC_PLATFORM_USETHREADS */ + + (void)isc__taskmgr_dispatch(); + + result = evloop(); + if (result != ISC_R_SUCCESS) + return (result); + +#endif /* ISC_PLATFORM_USETHREADS */ + + return (ISC_R_SUCCESS); +} + +isc_result_t +isc_app_shutdown(void) { + isc_boolean_t want_kill = ISC_TRUE; + char strbuf[ISC_STRERRORSIZE]; + + LOCK(&lock); + + REQUIRE(running); + + if (shutdown_requested) + want_kill = ISC_FALSE; + else + shutdown_requested = ISC_TRUE; + + UNLOCK(&lock); + + if (want_kill) { +#ifdef HAVE_LINUXTHREADS + int result; + + result = pthread_kill(main_thread, SIGTERM); + if (result != 0) { + isc__strerror(result, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_shutdown() pthread_kill: %s", + strbuf); + return (ISC_R_UNEXPECTED); + } +#else + if (kill(getpid(), SIGTERM) < 0) { + isc__strerror(errno, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_shutdown() kill: %s", strbuf); + return (ISC_R_UNEXPECTED); + } +#endif + } + + return (ISC_R_SUCCESS); +} + +isc_result_t +isc_app_reload(void) { + isc_boolean_t want_kill = ISC_TRUE; + char strbuf[ISC_STRERRORSIZE]; + + LOCK(&lock); + + REQUIRE(running); + + /* + * Don't send the reload signal if we're shutting down. + */ + if (shutdown_requested) + want_kill = ISC_FALSE; + + UNLOCK(&lock); + + if (want_kill) { +#ifdef HAVE_LINUXTHREADS + int result; + + result = pthread_kill(main_thread, SIGHUP); + if (result != 0) { + isc__strerror(result, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_reload() pthread_kill: %s", + strbuf); + return (ISC_R_UNEXPECTED); + } +#else + if (kill(getpid(), SIGHUP) < 0) { + isc__strerror(errno, strbuf, sizeof(strbuf)); + UNEXPECTED_ERROR(__FILE__, __LINE__, + "isc_app_reload() kill: %s", strbuf); + return (ISC_R_UNEXPECTED); + } +#endif + } + + return (ISC_R_SUCCESS); +} + +void +isc_app_finish(void) { + DESTROYLOCK(&lock); +} + +void +isc_app_block(void) { +#ifdef ISC_PLATFORM_USETHREADS + sigset_t sset; +#endif /* ISC_PLATFORM_USETHREADS */ + REQUIRE(running); + REQUIRE(!blocked); + + blocked = ISC_TRUE; +#ifdef ISC_PLATFORM_USETHREADS + blockedthread = pthread_self(); + RUNTIME_CHECK(sigemptyset(&sset) == 0 && + sigaddset(&sset, SIGINT) == 0 && + sigaddset(&sset, SIGTERM) == 0); + RUNTIME_CHECK(pthread_sigmask(SIG_UNBLOCK, &sset, NULL) == 0); +#endif /* ISC_PLATFORM_USETHREADS */ +} + +void +isc_app_unblock(void) { +#ifdef ISC_PLATFORM_USETHREADS + sigset_t sset; +#endif /* ISC_PLATFORM_USETHREADS */ + + REQUIRE(running); + REQUIRE(blocked); + + blocked = ISC_FALSE; + +#ifdef ISC_PLATFORM_USETHREADS + REQUIRE(blockedthread == pthread_self()); + + RUNTIME_CHECK(sigemptyset(&sset) == 0 && + sigaddset(&sset, SIGINT) == 0 && + sigaddset(&sset, SIGTERM) == 0); + RUNTIME_CHECK(pthread_sigmask(SIG_BLOCK, &sset, NULL) == 0); +#endif /* ISC_PLATFORM_USETHREADS */ +} |