diff options
Diffstat (limited to 'lib/libpthread/thread/thr_cancel.c')
| -rw-r--r-- | lib/libpthread/thread/thr_cancel.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/lib/libpthread/thread/thr_cancel.c b/lib/libpthread/thread/thr_cancel.c new file mode 100644 index 0000000..cf72d89 --- /dev/null +++ b/lib/libpthread/thread/thr_cancel.c @@ -0,0 +1,243 @@ +/* + * David Leonard <d@openbsd.org>, 1999. Public domain. + * $FreeBSD$ + */ +#include <sys/errno.h> +#include <pthread.h> +#include "pthread_private.h" + +static void finish_cancellation(void *arg); + +__weak_reference(_pthread_cancel, pthread_cancel); +__weak_reference(_pthread_setcancelstate, pthread_setcancelstate); +__weak_reference(_pthread_setcanceltype, pthread_setcanceltype); +__weak_reference(_pthread_testcancel, pthread_testcancel); + +int +_pthread_cancel(pthread_t pthread) +{ + int ret; + + if ((ret = _find_thread(pthread)) != 0) { + /* NOTHING */ + } else if (pthread->state == PS_DEAD || pthread->state == PS_DEADLOCK) { + ret = 0; + } else { + /* Protect the scheduling queues: */ + _thread_kern_sig_defer(); + + if (((pthread->cancelflags & PTHREAD_CANCEL_DISABLE) != 0) || + (((pthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) == 0) && + ((pthread->cancelflags & PTHREAD_AT_CANCEL_POINT) == 0))) + /* Just mark it for cancellation: */ + pthread->cancelflags |= PTHREAD_CANCELLING; + else { + /* + * Check if we need to kick it back into the + * run queue: + */ + switch (pthread->state) { + case PS_RUNNING: + /* No need to resume: */ + pthread->cancelflags |= PTHREAD_CANCELLING; + break; + + case PS_SPINBLOCK: + case PS_FDR_WAIT: + case PS_FDW_WAIT: + case PS_POLL_WAIT: + case PS_SELECT_WAIT: + /* Remove these threads from the work queue: */ + if ((pthread->flags & PTHREAD_FLAGS_IN_WORKQ) + != 0) + PTHREAD_WORKQ_REMOVE(pthread); + /* Fall through: */ + case PS_SIGTHREAD: + case PS_SLEEP_WAIT: + case PS_WAIT_WAIT: + case PS_SIGSUSPEND: + case PS_SIGWAIT: + /* Interrupt and resume: */ + pthread->interrupted = 1; + pthread->cancelflags |= PTHREAD_CANCELLING; + PTHREAD_NEW_STATE(pthread,PS_RUNNING); + break; + + case PS_JOIN: + /* + * Disconnect the thread from the joinee: + */ + if (pthread->join_status.thread != NULL) { + pthread->join_status.thread->joiner + = NULL; + pthread->join_status.thread = NULL; + } + pthread->cancelflags |= PTHREAD_CANCELLING; + PTHREAD_NEW_STATE(pthread, PS_RUNNING); + break; + + case PS_SUSPENDED: + if (pthread->suspended == SUSP_NO || + pthread->suspended == SUSP_YES || + pthread->suspended == SUSP_JOIN || + pthread->suspended == SUSP_NOWAIT) { + /* + * This thread isn't in any scheduling + * queues; just change it's state: + */ + pthread->cancelflags |= + PTHREAD_CANCELLING; + PTHREAD_SET_STATE(pthread, PS_RUNNING); + break; + } + /* FALLTHROUGH */ + case PS_MUTEX_WAIT: + case PS_COND_WAIT: + case PS_FDLR_WAIT: + case PS_FDLW_WAIT: + case PS_FILE_WAIT: + /* + * Threads in these states may be in queues. + * In order to preserve queue integrity, the + * cancelled thread must remove itself from the + * queue. Mark the thread as interrupted and + * needing cancellation, and set the state to + * running. When the thread resumes, it will + * remove itself from the queue and call the + * cancellation completion routine. + */ + pthread->interrupted = 1; + pthread->cancelflags |= PTHREAD_CANCEL_NEEDED; + PTHREAD_NEW_STATE(pthread,PS_RUNNING); + pthread->continuation = finish_cancellation; + break; + + case PS_DEAD: + case PS_DEADLOCK: + case PS_STATE_MAX: + /* Ignore - only here to silence -Wall: */ + break; + } + } + + /* Unprotect the scheduling queues: */ + _thread_kern_sig_undefer(); + + ret = 0; + } + return (ret); +} + +int +_pthread_setcancelstate(int state, int *oldstate) +{ + struct pthread *curthread = _get_curthread(); + int ostate; + int ret; + + ostate = curthread->cancelflags & PTHREAD_CANCEL_DISABLE; + + switch (state) { + case PTHREAD_CANCEL_ENABLE: + if (oldstate != NULL) + *oldstate = ostate; + curthread->cancelflags &= ~PTHREAD_CANCEL_DISABLE; + if ((curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0) + pthread_testcancel(); + ret = 0; + break; + case PTHREAD_CANCEL_DISABLE: + if (oldstate != NULL) + *oldstate = ostate; + curthread->cancelflags |= PTHREAD_CANCEL_DISABLE; + ret = 0; + break; + default: + ret = EINVAL; + } + + return (ret); +} + +int +_pthread_setcanceltype(int type, int *oldtype) +{ + struct pthread *curthread = _get_curthread(); + int otype; + int ret; + + otype = curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS; + switch (type) { + case PTHREAD_CANCEL_ASYNCHRONOUS: + if (oldtype != NULL) + *oldtype = otype; + curthread->cancelflags |= PTHREAD_CANCEL_ASYNCHRONOUS; + pthread_testcancel(); + ret = 0; + break; + case PTHREAD_CANCEL_DEFERRED: + if (oldtype != NULL) + *oldtype = otype; + curthread->cancelflags &= ~PTHREAD_CANCEL_ASYNCHRONOUS; + ret = 0; + break; + default: + ret = EINVAL; + } + + return (ret); +} + +void +_pthread_testcancel(void) +{ + struct pthread *curthread = _get_curthread(); + + if (((curthread->cancelflags & PTHREAD_CANCEL_DISABLE) == 0) && + ((curthread->cancelflags & PTHREAD_CANCELLING) != 0)) { + /* + * It is possible for this thread to be swapped out + * while performing cancellation; do not allow it + * to be cancelled again. + */ + curthread->cancelflags &= ~PTHREAD_CANCELLING; + _thread_exit_cleanup(); + pthread_exit(PTHREAD_CANCELED); + PANIC("cancel"); + } +} + +void +_thread_enter_cancellation_point(void) +{ + struct pthread *curthread = _get_curthread(); + + /* Look for a cancellation before we block: */ + pthread_testcancel(); + curthread->cancelflags |= PTHREAD_AT_CANCEL_POINT; +} + +void +_thread_leave_cancellation_point(void) +{ + struct pthread *curthread = _get_curthread(); + + curthread->cancelflags &= ~PTHREAD_AT_CANCEL_POINT; + /* Look for a cancellation after we unblock: */ + pthread_testcancel(); +} + +static void +finish_cancellation(void *arg) +{ + struct pthread *curthread = _get_curthread(); + + curthread->continuation = NULL; + curthread->interrupted = 0; + + if ((curthread->cancelflags & PTHREAD_CANCEL_NEEDED) != 0) { + curthread->cancelflags &= ~PTHREAD_CANCEL_NEEDED; + _thread_exit_cleanup(); + pthread_exit(PTHREAD_CANCELED); + } +} |
