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Diffstat (limited to 'signal/sig-internal.h')
| -rw-r--r-- | signal/sig-internal.h | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/signal/sig-internal.h b/signal/sig-internal.h new file mode 100644 index 00000000..6c86c796 --- /dev/null +++ b/signal/sig-internal.h @@ -0,0 +1,177 @@ +/* sig-internal.h - Internal signal handling interface. + 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/>. */ + +#ifndef SIG_INTERNAL_H +#define SIG_INTERNAL_H + +#include <signal.h> + +#include <sig-sysdep.h> + +#define sigmask(sig) (1ULL << (sig - 1)) +#define STOPSIGS (sigmask (SIGTTIN) | sigmask (SIGTTOU) | \ + sigmask (SIGSTOP) | sigmask (SIGTSTP)) + +/* General lock. Protects PROCESS_PENDING, PROCESS_PENDING_INFO, + SIGWAITERS. */ +extern pthread_mutex_t sig_lock; + +/* "Signals generated for the process shall be delivered to exactly + one of those threads within the process which is in a call to a + sigwait() function selecting that signal or has not blocked + delivery of the signal. If there are no threads in a call to a + sigwait() function selecting that signal, and if all threads within + the process block delivery of the signal, the signal shall remaing + pending on the process" (2.4.1). + + This variable is protected by SIG_LOCK. */ +extern sigset_t process_pending; +extern siginfo_t process_pending_info[NSIG]; + +struct sigwaiter; + +/* The per-thread signal state. */ +struct signal_state +{ + /* Protects the following fields. STACK.SA_FLAGS may be accessed + using atomic operations. */ + pthread_mutex_t lock; + + /* Pending signals. */ + sigset_t pending; + + /* Blocked signals (i.e., the signal mask). */ + sigset_t blocked; + + stack_t stack; + struct sigaction actions[NSIG]; + siginfo_t info[NSIG]; + + /* If the thread is blocked in a call to sigwait. */ + struct sigwaiter *sigwaiter; +}; + +#define PTHREAD_SIGNAL_MEMBERS struct signal_state ss; + +/* Arranges for thread TID to call signal_dispatch. Must not be + called if TID is the caller and an alternate stack is not required. + In this case, the caller should call signal_dispatch directly. */ +extern void signal_dispatch_lowlevel (struct signal_state *ss, + pthread_t tid, siginfo_t si); + +/* 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. */ +extern void signal_dispatch (struct signal_state *ss, siginfo_t *si); + +#ifndef SIGNAL_DISPATCH_ENTRY +#define SIGNAL_DISPATCH_ENTRY +#endif + +#ifndef SIGNAL_DISPATCH_EXIT +#define SIGNAL_DISPATCH_EXIT +#endif + +/* When a thread calls sigwait and a requested signal is not pending, + it allocates the following structure, fills it in, adds it to + sigwaiters and sleeps. */ +struct sigwaiter +{ + struct sigwaiter *next; + struct sigwaiter *prev; + + /* Thread's signal state. */ + struct signal_state *ss; + + /* Signals this thread is waiting for. */ + sigset_t signals; + + /* The selected signal is returned here. The waiter also + futex_waits on this info.si_signo. */ + siginfo_t info; +}; + +/* This variable is protected by SIG_LOCK. */ +extern struct sigwaiter *sigwaiters; + +/* Block the caller waiting for a signal in set SET. SIG_LOCK and + SS->LOCK must be held and will be unlocked by this function before + blocking. */ +extern siginfo_t sigwaiter_block (struct signal_state *ss, + const sigset_t *restrict set); + +/* Unblock the waiter WAITER. SIG_LOCK and WAITER->SS->LOCK must be + held. Both will be dropped on return. */ +extern void sigwaiter_unblock (struct sigwaiter *waiter); + +enum sig_action { sig_core, sig_terminate, sig_ignore, sig_cont, sig_stop }; + +static inline enum sig_action +default_action (int signo) +{ + switch (signo) + { + case SIGABRT: + case SIGBUS: + case SIGFPE: + case SIGILL: + case SIGQUIT: + case SIGSEGV: + case SIGSTKFLT: + case SIGSYS: + case SIGTRAP: + case SIGXCPU: + case SIGXFSZ: + return sig_core; + + case SIGALRM: + case SIGHUP: + case SIGINT: + case SIGIO: /* Perhaps ignore? */ + case SIGKILL: + case SIGPIPE: + case SIGPROF: + case SIGTERM: + case SIGUSR1: + case SIGUSR2: + case SIGVTALRM: + return sig_terminate; + + case SIGCHLD: + case SIGPWR: + case SIGURG: + case SIGWINCH: + return sig_ignore; + + case SIGCONT: + return sig_cont; + + case SIGSTOP: + case SIGTSTP: + case SIGTTIN: + case SIGTTOU: + return sig_stop; + } + + panic ("Unknown signal number: %d", signo); +} + +#endif |