diff options
Diffstat (limited to 'linuxthreads/signals.c')
| -rw-r--r-- | linuxthreads/signals.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/linuxthreads/signals.c b/linuxthreads/signals.c new file mode 100644 index 0000000..905e11e --- /dev/null +++ b/linuxthreads/signals.c @@ -0,0 +1,148 @@ +/* Linuxthreads - a simple clone()-based implementation of Posix */ +/* threads for Linux. */ +/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ +/* */ +/* This program is free software; you can redistribute it and/or */ +/* modify it under the terms of the GNU Library General Public License */ +/* as published by the Free Software Foundation; either version 2 */ +/* of the License, or (at your option) any later version. */ +/* */ +/* This program is distributed in the hope that it will be useful, */ +/* but WITHOUT ANY WARRANTY; without even the implied warranty of */ +/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ +/* GNU Library General Public License for more details. */ + +/* Handling of signals */ + +#include <errno.h> +#include <signal.h> +#include "pthread.h" +#include "internals.h" +#include "spinlock.h" + +int pthread_sigmask(int how, const sigset_t * newmask, sigset_t * oldmask) +{ + sigset_t mask; + + if (newmask != NULL) { + mask = *newmask; + /* Don't allow PTHREAD_SIG_RESTART to be unmasked. + Don't allow PTHREAD_SIG_CANCEL to be masked. */ + switch(how) { + case SIG_SETMASK: + sigaddset(&mask, PTHREAD_SIG_RESTART); + sigdelset(&mask, PTHREAD_SIG_CANCEL); + break; + case SIG_BLOCK: + sigdelset(&mask, PTHREAD_SIG_CANCEL); + break; + case SIG_UNBLOCK: + sigdelset(&mask, PTHREAD_SIG_RESTART); + break; + } + newmask = &mask; + } + if (sigprocmask(how, newmask, oldmask) == -1) + return errno; + else + return 0; +} + +int pthread_kill(pthread_t thread, int signo) +{ + pthread_handle handle = thread_handle(thread); + int pid; + + acquire(&handle->h_spinlock); + if (invalid_handle(handle, thread)) { + release(&handle->h_spinlock); + return ESRCH; + } + pid = handle->h_descr->p_pid; + release(&handle->h_spinlock); + if (kill(pid, signo) == -1) + return errno; + else + return 0; +} + +/* The set of signals on which some thread is doing a sigwait */ +static sigset_t sigwaited; +static pthread_mutex_t sigwaited_mut = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t sigwaited_changed = PTHREAD_COND_INITIALIZER; + +int sigwait(const sigset_t * set, int * sig) +{ + volatile pthread_descr self = thread_self(); + sigset_t mask; + int s; + struct sigaction action, saved_signals[NSIG]; + sigjmp_buf jmpbuf; + + pthread_mutex_lock(&sigwaited_mut); + /* Make sure no other thread is waiting on our signals */ +test_again: + for (s = 1; s < NSIG; s++) { + if (sigismember(set, s) && sigismember(&sigwaited, s)) { + pthread_cond_wait(&sigwaited_changed, &sigwaited_mut); + goto test_again; + } + } + /* Get ready to block all signals except those in set + and the cancellation signal */ + sigfillset(&mask); + sigdelset(&mask, PTHREAD_SIG_CANCEL); + /* Signals in set are assumed blocked on entrance */ + /* Install our signal handler on all signals in set, + and unblock them in mask. + Also mark those signals as being sigwaited on */ + for (s = 1; s < NSIG; s++) { + if (sigismember(set, s) && s != PTHREAD_SIG_CANCEL) { + sigdelset(&mask, s); + action.sa_handler = __pthread_sighandler; + sigemptyset(&action.sa_mask); + action.sa_flags = 0; + sigaction(s, &action, &(saved_signals[s])); + sigaddset(&sigwaited, s); + } + } + pthread_mutex_unlock(&sigwaited_mut); + + /* Test for cancellation */ + if (sigsetjmp(jmpbuf, 1) == 0) { + self->p_cancel_jmp = &jmpbuf; + if (! (self->p_canceled && self->p_cancelstate == PTHREAD_CANCEL_ENABLE)) { + /* Reset the signal count */ + self->p_signal = 0; + /* Unblock the signals and wait for them */ + sigsuspend(&mask); + } + } + self->p_cancel_jmp = NULL; + /* The signals are now reblocked. Restore the sighandlers. */ + pthread_mutex_lock(&sigwaited_mut); + for (s = 1; s < NSIG; s++) { + if (sigismember(set, s) && s != PTHREAD_SIG_CANCEL) { + sigaction(s, &(saved_signals[s]), NULL); + sigdelset(&sigwaited, s); + } + } + pthread_cond_broadcast(&sigwaited_changed); + pthread_mutex_unlock(&sigwaited_mut); + /* Check for cancellation */ + pthread_testcancel(); + /* We should have self->p_signal != 0 and equal to the signal received */ + *sig = self->p_signal; + return 0; +} + +int raise (int sig) +{ + int retcode = pthread_kill(pthread_self(), sig); + if (retcode == 0) + return 0; + else { + errno = retcode; + return -1; + } +} |