diff options
Diffstat (limited to 'lib/libpthread/thread/thr_sig.c')
| -rw-r--r-- | lib/libpthread/thread/thr_sig.c | 782 |
1 files changed, 782 insertions, 0 deletions
diff --git a/lib/libpthread/thread/thr_sig.c b/lib/libpthread/thread/thr_sig.c new file mode 100644 index 0000000..fa63b5f --- /dev/null +++ b/lib/libpthread/thread/thr_sig.c @@ -0,0 +1,782 @@ +/* + * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by John Birrell. + * 4. Neither the name of the author nor the names of any co-contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + */ +#include <sys/param.h> +#include <sys/types.h> +#include <sys/signalvar.h> +#include <signal.h> +#include <fcntl.h> +#include <unistd.h> +#include <setjmp.h> +#include <errno.h> +#include <pthread.h> +#include "thr_private.h" + +/* Prototypes: */ +static void thread_sig_handle_special(int sig); + +static void thread_sig_add(struct pthread *pthread, int sig, int has_args); +static void thread_sig_check_state(struct pthread *pthread, int sig); +static struct pthread *thread_sig_find(int sig); +static void thread_sigframe_add(struct pthread *thread, int sig, + int has_args); +static void thread_sigframe_save(struct pthread *thread, + struct pthread_state_data *psd); +static void thread_sigframe_restore(struct pthread *thread, + struct pthread_state_data *psd); + +/* #define DEBUG_SIGNAL */ +#ifdef DEBUG_SIGNAL +#define DBG_MSG stdout_debug +#else +#define DBG_MSG(x...) +#endif + +/* + * Dispatch a signal to a thread, if appropriate. + */ +void +_thread_sig_dispatch(int sig) +{ + struct pthread *pthread; + + DBG_MSG(">>> _thread_sig_dispatch(%d)\n", sig); + + thread_sig_handle_special(sig); + if (sigismember(&_thread_sigmask, sig)) + /* Don't deliver the signal if it's masked. */ + return; + /* Mask the signal until it's handled. */ + sigaddset(&_thread_sigmask, sig); + /* This signal will be handled; clear the pending flag. */ + sigdelset(&_thread_sigpending, sig); + + /* + * Deliver the signal to a thread. + */ + if ((pthread = thread_sig_find(sig)) == NULL) { + DBG_MSG("No thread to handle signal %d\n", sig); + return; + } + DBG_MSG("Got signal %d, selecting thread %p\n", sig, pthread); + thread_sig_add(pthread, sig, /*has_args*/ 1); +} + +/* + * Find a thread that can handle the signal. + */ +static struct pthread * +thread_sig_find(int sig) +{ + struct pthread *curthread = _get_curthread(); + struct pthread *pthread, *pthread_next; + struct pthread *suspended_thread, *signaled_thread; + + DBG_MSG("Looking for thread to handle signal %d\n", sig); + /* Check if the signal requires a dump of thread information: */ + if (sig == SIGINFO) { + /* Dump thread information to file: */ + _thread_dump_info(); + + /* Unblock this signal to allow further dumps: */ + sigdelset(&_thread_sigmask, sig); + } + + /* + * Enter a loop to look for threads that have the signal + * unmasked. POSIX specifies that a thread in a sigwait + * will get the signal over any other threads. Second + * preference will be threads in in a sigsuspend. Third + * preference will be the current thread. If none of the + * above, then the signal is delivered to the first thread + * that is found. Note that if a custom handler is not + * installed, the signal only affects threads in sigwait. + */ + suspended_thread = NULL; + if ((curthread != &_thread_kern_thread) && + !sigismember(&curthread->mailbox.tm_context.uc_sigmask, sig)) + signaled_thread = curthread; + else + signaled_thread = NULL; + + for (pthread = TAILQ_FIRST(&_waitingq); + pthread != NULL; pthread = pthread_next) { + /* + * Grab the next thread before possibly destroying + * the link entry. + */ + pthread_next = TAILQ_NEXT(pthread, pqe); + + if ((pthread->state == PS_SIGWAIT) && + sigismember(pthread->data.sigwait, sig)) { + /* Change the state of the thread to run: */ + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + + /* + * A signal handler is not invoked for threads + * in sigwait. Clear the blocked and pending + * flags. + */ + sigdelset(&_thread_sigmask, sig); + sigdelset(&_thread_sigpending, sig); + + /* Return the signal number: */ + pthread->signo = sig; + + /* + * POSIX doesn't doesn't specify which thread + * will get the signal if there are multiple + * waiters, so we give it to the first thread + * we find. + * + * Do not attempt to deliver this signal + * to other threads and do not add the signal + * to the process pending set. + */ + return (NULL); + } + if (!sigismember( + &pthread->mailbox.tm_context.uc_sigmask, sig) && + ((pthread->flags & PTHREAD_FLAGS_SUSPENDED) == 0)) { + if (pthread->state == PS_SIGSUSPEND) { + if (suspended_thread == NULL) + suspended_thread = pthread; + } else if (signaled_thread == NULL) + signaled_thread = pthread; + } + } + + /* + * If we didn't find a thread in the waiting queue, + * check the all threads queue: + */ + if (suspended_thread == NULL && + signaled_thread == NULL) { + /* + * Enter a loop to look for other threads + * capable of receiving the signal: + */ + TAILQ_FOREACH(pthread, &_thread_list, tle) { + if (!sigismember( + &pthread->mailbox.tm_context.uc_sigmask, sig)) { + signaled_thread = pthread; + break; + } + } + } + + if (suspended_thread == NULL && + signaled_thread == NULL) + /* + * Add it to the set of signals pending + * on the process: + */ + sigaddset(&_thread_sigpending, sig); + else { + /* + * We only deliver the signal to one thread; + * give preference to the suspended thread: + */ + if (suspended_thread != NULL) + pthread = suspended_thread; + else + pthread = signaled_thread; + return (pthread); + } + + /* Returns nothing. */ + return (NULL); +} + +#if __XXX_NOT_YET__ +void +_thread_sig_check_pending(struct pthread *pthread) +{ + sigset_t sigset; + int i; + + /* + * Check if there are pending signals for the running + * thread or process that aren't blocked: + */ + sigset = pthread->sigpend; + SIGSETOR(sigset, _thread_sigpending); + SIGSETNAND(sigset, pthread->sigmask); + SIGSETNAND(sigset, _thread_sigmask); + if (SIGNOTEMPTY(sigset)) { + for (i = 1; i < NSIG; i++) { + if (sigismember(&sigset, i) != 0) { + if (sigismember(&pthread->sigpend, i) != 0) + thread_sig_add(pthread, i, + /*has_args*/ 0); + else { + thread_sig_add(pthread, i, + /*has_args*/ 1); + sigdelset(&_thread_sigpending, i); + } + } + } + } +} +#endif + +#if __XXX_NOT_YET__ +/* + * This can only be called from the kernel scheduler. It assumes that + * all thread contexts are saved and that a signal frame can safely be + * added to any user thread. + */ +void +_thread_sig_handle_pending(void) +{ + struct pthread *pthread; + int sig; + + /* + * Check the array of pending signals: + */ + for (sig = 1; sig <= NSIG; sig++) { + if (sigismember(&_thread_sigpending, sig)) { + /* This signal is no longer pending. */ + sigdelset(&_thread_sigpending, sig); + /* Some signals need special handling. */ + thread_sig_handle_special(sig); + /* Deliver the signal. */ + if (sigismember(&_thread_sigmask, sig)) { + sigaddset(&_thread_sigmask, sig); + if ((pthread = thread_sig_find(sig)) != NULL) { + /* + * Setup the target thread to receive + * the signal: + */ + thread_sig_add(pthread, sig, + /*has_args*/ 1); + } + } + } + } +} +#endif + +/* + * Do special processing to the thread states before we deliver + * a signal to the application. + */ +static void +thread_sig_handle_special(int sig) +{ + struct pthread *pthread, *pthread_next; + int i; + + switch (sig) { + case SIGCHLD: + /* + * Enter a loop to wake up all threads waiting + * for a process to complete: + */ + for (pthread = TAILQ_FIRST(&_waitingq); + pthread != NULL; pthread = pthread_next) { + /* + * Grab the next thread before possibly + * destroying the link entry: + */ + pthread_next = TAILQ_NEXT(pthread, pqe); + + /* + * If this thread is waiting for a child + * process to complete, wake it up: + */ + if (pthread->state == PS_WAIT_WAIT) { + /* Make the thread runnable: */ + PTHREAD_NEW_STATE(pthread,PS_RUNNING); + + /* Return the signal number: */ + pthread->signo = sig; + } + } + break; + + /* + * POSIX says that pending SIGCONT signals are + * discarded when one of these signals occurs. + */ + case SIGTSTP: + case SIGTTIN: + case SIGTTOU: + /* + * Enter a loop to discard pending SIGCONT + * signals: + */ + TAILQ_FOREACH(pthread, &_thread_list, tle) { + sigdelset(&pthread->sigpend, SIGCONT); + } + break; + + default: + break; + } +} + +/* + * Perform thread specific actions in response to a signal. + * This function is only called if there is a handler installed + * for the signal, and if the target thread has the signal + * unmasked. + */ +static void +thread_sig_add(struct pthread *pthread, int sig, int has_args) +{ + int suppress_handler = 0; + + /* Make sure this signal isn't still in the pending set: */ + sigdelset(&pthread->sigpend, sig); + + /* + * Process according to thread state: + */ + switch (pthread->state) { + /* + * States which do not change when a signal is trapped: + */ + case PS_DEAD: + case PS_DEADLOCK: + case PS_STATE_MAX: + /* + * You can't call a signal handler for threads in these + * states. + */ + suppress_handler = 1; + break; + + /* + * States which do not need any cleanup handling when signals + * occur: + */ + case PS_RUNNING: + /* + * Remove the thread from the queue before changing its + * priority: + */ + if ((pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) != 0) + PTHREAD_PRIOQ_REMOVE(pthread); + break; + + case PS_SUSPENDED: + break; + + case PS_SPINBLOCK: + /* Remove the thread from the workq and waitq: */ + PTHREAD_WORKQ_REMOVE(pthread); + PTHREAD_WAITQ_REMOVE(pthread); + /* Make the thread runnable: */ + PTHREAD_SET_STATE(pthread, PS_RUNNING); + break; + + case PS_SIGWAIT: + /* The signal handler is not called for threads in SIGWAIT. */ + suppress_handler = 1; + /* Wake up the thread if the signal is blocked. */ + if (sigismember(pthread->data.sigwait, sig)) { + /* Change the state of the thread to run: */ + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + + /* Return the signal number: */ + pthread->signo = sig; + } else + /* Increment the pending signal count. */ + sigaddset(&pthread->sigpend, sig); + break; + + /* + * The wait state is a special case due to the handling of + * SIGCHLD signals. + */ + case PS_WAIT_WAIT: + if (sig == SIGCHLD) { + /* Change the state of the thread to run: */ + PTHREAD_WAITQ_REMOVE(pthread); + PTHREAD_SET_STATE(pthread, PS_RUNNING); + + /* Return the signal number: */ + pthread->signo = sig; + } + else { + /* + * Mark the thread as interrupted only if the + * restart flag is not set on the signal action: + */ + PTHREAD_WAITQ_REMOVE(pthread); + PTHREAD_SET_STATE(pthread, PS_RUNNING); + } + break; + + /* + * States which cannot be interrupted but still require the + * signal handler to run: + */ + case PS_COND_WAIT: + case PS_MUTEX_WAIT: + /* + * Remove the thread from the wait queue. It will + * be added back to the wait queue once all signal + * handlers have been invoked. + */ + PTHREAD_WAITQ_REMOVE(pthread); + break; + + case PS_JOIN: + /* + * Remove the thread from the wait queue. It will + * be added back to the wait queue once all signal + * handlers have been invoked. + */ + PTHREAD_WAITQ_REMOVE(pthread); + /* Make the thread runnable: */ + PTHREAD_SET_STATE(pthread, PS_RUNNING); + break; + + case PS_SLEEP_WAIT: + /* + * Unmasked signals always cause sleep to terminate early, + * regardless of SA_RESTART: + */ + pthread->interrupted = 1; + /* Remove threads in poll and select from the workq: */ + if ((pthread->flags & PTHREAD_FLAGS_IN_WORKQ) != 0) + PTHREAD_WORKQ_REMOVE(pthread); + PTHREAD_WAITQ_REMOVE(pthread); + PTHREAD_SET_STATE(pthread, PS_RUNNING); + break; + + case PS_SIGSUSPEND: + PTHREAD_WAITQ_REMOVE(pthread); + PTHREAD_SET_STATE(pthread, PS_RUNNING); + break; + } + + DBG_MSG(">>> suppress_handler = %d\n", suppress_handler); + + if (suppress_handler == 0) { + /* Setup a signal frame and save the current threads state: */ + thread_sigframe_add(pthread, sig, has_args); + + /* + * Signals are deferred until just before the threads + * signal handler is invoked: + */ + pthread->sig_defer_count = 1; + + /* Make sure the thread is runnable: */ + if (pthread->state != PS_RUNNING) + PTHREAD_SET_STATE(pthread, PS_RUNNING); + /* + * The thread should be removed from all scheduling + * queues at this point. Raise the priority and place + * the thread in the run queue. It is also possible + * for a signal to be sent to a suspended thread, + * mostly via pthread_kill(). If a thread is suspended, + * don't insert it into the priority queue; just set + * its state to suspended and it will run the signal + * handler when it is resumed. + */ + pthread->active_priority |= PTHREAD_SIGNAL_PRIORITY; + if ((pthread->flags & PTHREAD_FLAGS_SUSPENDED) != 0) + PTHREAD_SET_STATE(pthread, PS_SUSPENDED); + else + PTHREAD_PRIOQ_INSERT_TAIL(pthread); + } +} + +#if __XXX_NOT_YET__ +static void +thread_sig_check_state(struct pthread *pthread, int sig) +{ + /* + * Process according to thread state: + */ + switch (pthread->state) { + /* + * States which do not change when a signal is trapped: + */ + case PS_DEAD: + case PS_DEADLOCK: + case PS_STATE_MAX: + case PS_RUNNING: + case PS_SUSPENDED: + case PS_SPINBLOCK: + case PS_COND_WAIT: + case PS_JOIN: + case PS_MUTEX_WAIT: + break; + + case PS_SIGWAIT: + /* Wake up the thread if the signal is blocked. */ + if (sigismember(pthread->data.sigwait, sig)) { + /* Change the state of the thread to run: */ + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + + /* Return the signal number: */ + pthread->signo = sig; + } else + /* Increment the pending signal count. */ + sigaddset(&pthread->sigpend, sig); + break; + + /* + * The wait state is a special case due to the handling of + * SIGCHLD signals. + */ + case PS_WAIT_WAIT: + if (sig == SIGCHLD) { + /* + * Remove the thread from the wait queue and + * make it runnable: + */ + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + + /* Return the signal number: */ + pthread->signo = sig; + } + break; + + case PS_FDLR_WAIT: + case PS_FDLW_WAIT: + case PS_SIGSUSPEND: + case PS_SLEEP_WAIT: + /* + * Remove the thread from the wait queue and make it + * runnable: + */ + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + + /* Flag the operation as interrupted: */ + pthread->interrupted = 1; + break; + + /* + * These states are additionally in the work queue: + */ + case PS_FDR_WAIT: + case PS_FDW_WAIT: + case PS_FILE_WAIT: + case PS_POLL_WAIT: + case PS_SELECT_WAIT: + /* + * Remove the thread from the wait and work queues, and + * make it runnable: + */ + PTHREAD_WORKQ_REMOVE(pthread); + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + + /* Flag the operation as interrupted: */ + pthread->interrupted = 1; + break; + } +} +#endif + +#if __XXX_NOT_YET__ +/* + * Send a signal to a specific thread (ala pthread_kill): + */ +void +_thread_sig_send(struct pthread *pthread, int sig) +{ + struct pthread *curthread = _get_curthread(); + + /* Check for signals whose actions are SIG_DFL: */ + if (_thread_sigact[sig - 1].sa_handler == SIG_DFL) { + /* + * Check to see if a temporary signal handler is + * installed for sigwaiters: + */ + if (_thread_dfl_count[sig] == 0) + /* + * Deliver the signal to the process if a handler + * is not installed: + */ + kill(getpid(), sig); + /* + * Assuming we're still running after the above kill(), + * make any necessary state changes to the thread: + */ + thread_sig_check_state(pthread, sig); + } + /* + * Check that the signal is not being ignored: + */ + else if (_thread_sigact[sig - 1].sa_handler != SIG_IGN) { + if (pthread->state == PS_SIGWAIT && + sigismember(pthread->data.sigwait, sig)) { + /* Change the state of the thread to run: */ + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + + /* Return the signal number: */ + pthread->signo = sig; + } else if (sigismember(&pthread->sigmask, sig)) + /* Add the signal to the pending set: */ + sigaddset(&pthread->sigpend, sig); + else if (pthread == curthread) + /* Call the signal handler for the current thread: */ + thread_sig_invoke_handler(sig, NULL, NULL); + else { + /* Protect the scheduling queues: */ + _thread_kern_sig_defer(); + /* + * Perform any state changes due to signal + * arrival: + */ + thread_sig_add(pthread, sig, /* has args */ 0); + /* Unprotect the scheduling queues: */ + _thread_kern_sig_undefer(); + } + } +} +#endif + +/* + * User thread signal handler wrapper. + * + * thread - current running thread + */ +void +_thread_sig_wrapper(int sig, siginfo_t *info, ucontext_t *context) +{ + struct pthread_state_data psd; + struct pthread *thread = _get_curthread(); + __siginfohandler_t *handler; + + /* Save the thread's previous state. */ + thread_sigframe_save(thread, &psd); + + /* Check the threads previous state: */ + if (psd.psd_state != PS_RUNNING) { + /* + * Do a little cleanup handling for those threads in + * queues before calling the signal handler. Signals + * for these threads are temporarily blocked until + * after cleanup handling. + */ + switch (psd.psd_state) { + case PS_COND_WAIT: + _cond_wait_backout(thread); + psd.psd_state = PS_RUNNING; + break; + + case PS_MUTEX_WAIT: + _mutex_lock_backout(thread); + psd.psd_state = PS_RUNNING; + break; + + default: + break; + } + } + + /* Unblock the signal in case we don't return from the handler. */ + /* + * XXX - This is totally bogus. We need to lock the signal mask + * somehow. + */ + sigdelset(&_thread_sigmask, sig); + + /* + * Lower the priority before calling the handler in case + * it never returns (longjmps back): + */ + thread->active_priority &= ~PTHREAD_SIGNAL_PRIORITY; + + /* + * Reenable interruptions without checking for the need to + * context switch. + */ + thread->sig_defer_count = 0; + + if (_thread_sigact[sig -1].sa_handler != NULL) { + handler = (__siginfohandler_t *) + _thread_sigact[sig - 1].sa_handler; + handler(sig, info, context); + } + + /* Restore the signal frame. */ + thread_sigframe_restore(thread, &psd); + + /* The signal mask was restored; check for any pending signals. */ + /* XXX - thread->check_pending = 1; */ +} + +static void +thread_sigframe_add(struct pthread *thread, int sig, int has_args) +{ + struct pthread_signal_frame *psf = NULL; + unsigned long stackp; + + /* Add a signal frame to the stack, pointing to our signal wrapper. */ + signalcontext(&thread->mailbox.tm_context, sig, + (__sighandler_t *)_thread_sig_wrapper); + + /* Setup the new signal mask. */ + SIGSETOR(thread->mailbox.tm_context.uc_sigmask, + _thread_sigact[sig - 1].sa_mask); + sigaddset(&thread->mailbox.tm_context.uc_sigmask, sig); +} + +static void +thread_sigframe_restore(struct pthread *thread, struct pthread_state_data *psd) +{ + thread->wakeup_time = psd->psd_wakeup_time; + thread->data = psd->psd_wait_data; + thread->state = psd->psd_state; + thread->flags = psd->psd_flags; + thread->interrupted = psd->psd_interrupted; + thread->sig_defer_count = psd->psd_sig_defer_count; +} + +static void +thread_sigframe_save(struct pthread *thread, struct pthread_state_data *psd) +{ + psd->psd_wakeup_time = thread->wakeup_time; + psd->psd_wait_data = thread->data; + psd->psd_state = thread->state; + psd->psd_flags = thread->flags & + (PTHREAD_FLAGS_PRIVATE | PTHREAD_FLAGS_TRACE); + psd->psd_interrupted = thread->interrupted; + psd->psd_sig_defer_count = thread->sig_defer_count; +} + +void +_thread_sig_handler(int sig, siginfo_t *info, ucontext_t *context) +{ + + /* Nothing. */ +} |
