diff options
Diffstat (limited to 'signal/signal-dispatch.c')
| -rw-r--r-- | signal/signal-dispatch.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/signal/signal-dispatch.c b/signal/signal-dispatch.c new file mode 100644 index 00000000..40440b70 --- /dev/null +++ b/signal/signal-dispatch.c @@ -0,0 +1,117 @@ +/* signal-dispatch.c - Signal dispatcher. + Copyright (C) 2008 Free Software Foundation, Inc. + Written by Neal H. Walfield <neal@gnu.org>. + + This file is part of the GNU Hurd. + + The GNU Hurd is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License + as published by the Free Software Foundation; either version 3 of + the License, or (at your option) any later version. + + The GNU Hurd 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this program. If not, see + <http://www.gnu.org/licenses/>. */ + +#include "sig-internal.h" + +/* This is the signal handler entry point. A thread is forced into + this state when it receives a signal. We need to save the thread's + state and then invoke the high-level signal dispatcher. SS->LOCK + is locked by the caller. */ +void +signal_dispatch (struct signal_state *ss, siginfo_t *si) +{ + SIGNAL_DISPATCH_ENTRY; + + int signo = si->si_signo; + + assert (signo > 0 && signo < NSIG); + assert (pthread_mutex_trylock (&ss->lock) == EBUSY); + + do + { + if ((sigmask (signo) & STOPSIGS)) + /* Stop signals clear a pending SIGCONT even if they + are handled or ignored (but not if preempted). */ + { + sigdelset (&ss->pending, SIGCONT); + sigdelset (&process_pending, SIGCONT); + } + else if ((signo == SIGCONT)) + /* Even if handled or ignored (but not preempted), SIGCONT + clears stop signals and resumes the process. */ + { + ss->pending &= ~STOPSIGS; + process_pending &= ~STOPSIGS; + } + + void (*handler)(int, siginfo_t *, void *) + = ss->actions[signo - 1].sa_sigaction; + + /* Reset to SIG_DFL if requested. SIGILL and SIGTRAP cannot + be automatically reset when delivered; the system silently + enforces this restriction (sigaction). */ + if (ss->actions[signo - 1].sa_flags & SA_RESETHAND + && signo != SIGILL && signo != SIGTRAP) + ss->actions[signo - 1].sa_handler = SIG_DFL; + + sigset_t orig_blocked = ss->blocked; + /* Block requested signals while running the handler. */ + ss->blocked |= ss->actions[signo - 1].sa_mask; + + /* Block SIGNO unless we're asked not to. */ + if (! (ss->actions[signo - 1].sa_flags & (SA_RESETHAND | SA_NODEFER))) + sigaddset (&ss->blocked, signo); + + sigdelset (&ss->pending, signo); + pthread_mutex_unlock (&ss->lock); + + pthread_mutex_lock (&sig_lock); + sigdelset (&process_pending, signo); + pthread_mutex_unlock (&sig_lock); + + if (handler == (void *) SIG_DFL) + { + enum sig_action action = default_action (signo); + + if (action == sig_terminate || action == sig_core) + _exit (128 + signo); + + if (action == sig_stop) + /* XXX: Implement me. */ + panic ("Stopping process unimplemented."); + + if (action == sig_cont) + /* XXX: Implement me. */; + panic ("Continuing process unimplemented."); + } + else if (handler == (void *) SIG_IGN) + ; + else + handler (signo, si, NULL); + + pthread_mutex_lock (&ss->lock); + + /* "When a thread's signal mask is changed in a signal-catching + function that is installed by sigaction(), the restoration of + the signal mask on return from the signal-catching function + overrides that change (see sigaction())" (sigprocmask). */ + ss->blocked = orig_blocked; + + sigset_t pending = ~ss->blocked & ss->pending; + if (! pending) + pending = ~ss->blocked & process_pending; + signo = l4_lsb64 (pending); + } + while (signo); + + pthread_mutex_unlock (&ss->lock); + + SIGNAL_DISPATCH_EXIT; +} |