diff options
Diffstat (limited to 'libpthread/linuxthreads/signals.c')
| -rw-r--r-- | libpthread/linuxthreads/signals.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/libpthread/linuxthreads/signals.c b/libpthread/linuxthreads/signals.c new file mode 100644 index 000000000..de156e15a --- /dev/null +++ b/libpthread/linuxthreads/signals.c @@ -0,0 +1,239 @@ +/* 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 <stdio.h> +#include "pthread.h" +#include "internals.h" +#include "spinlock.h" +#include <ucontext.h> +#include <sigcontextinfo.h> + +/* mods for uClibc: __libc_sigaction is not in any standard headers */ +extern int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact); + +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; + + __pthread_lock(&handle->h_lock, NULL); + if (invalid_handle(handle, thread)) { + __pthread_unlock(&handle->h_lock); + return ESRCH; + } + pid = handle->h_descr->p_pid; + __pthread_unlock(&handle->h_lock); + if (kill(pid, signo) == -1) + return errno; + else + return 0; +} + +/* User-provided signal handlers */ +typedef void (*arch_sighandler_t) __PMT ((int, SIGCONTEXT)); +static union +{ + arch_sighandler_t old; + void (*rt) (int, struct siginfo *, struct ucontext *); +} sighandler[NSIG]; + +/* The wrapper around user-provided signal handlers */ +static void pthread_sighandler(int signo, SIGCONTEXT ctx) +{ + pthread_descr self = thread_self(); + char * in_sighandler; + /* If we're in a sigwait operation, just record the signal received + and return without calling the user's handler */ + if (THREAD_GETMEM(self, p_sigwaiting)) { + THREAD_SETMEM(self, p_sigwaiting, 0); + THREAD_SETMEM(self, p_signal, signo); + return; + } + /* Record that we're in a signal handler and call the user's + handler function */ + in_sighandler = THREAD_GETMEM(self, p_in_sighandler); + if (in_sighandler == NULL) + THREAD_SETMEM(self, p_in_sighandler, CURRENT_STACK_FRAME); + sighandler[signo].old(signo, SIGCONTEXT_EXTRA_ARGS ctx); + if (in_sighandler == NULL) + THREAD_SETMEM(self, p_in_sighandler, NULL); +} + +/* The same, this time for real-time signals. */ +static void pthread_sighandler_rt(int signo, struct siginfo *si, + struct ucontext *uc) +{ + pthread_descr self = thread_self(); + char * in_sighandler; + /* If we're in a sigwait operation, just record the signal received + and return without calling the user's handler */ + if (THREAD_GETMEM(self, p_sigwaiting)) { + THREAD_SETMEM(self, p_sigwaiting, 0); + THREAD_SETMEM(self, p_signal, signo); + return; + } + /* Record that we're in a signal handler and call the user's + handler function */ + in_sighandler = THREAD_GETMEM(self, p_in_sighandler); + if (in_sighandler == NULL) + THREAD_SETMEM(self, p_in_sighandler, CURRENT_STACK_FRAME); + sighandler[signo].rt(signo, si, uc); + if (in_sighandler == NULL) + THREAD_SETMEM(self, p_in_sighandler, NULL); +} + +/* The wrapper around sigaction. Install our own signal handler + around the signal. */ +int sigaction(int sig, const struct sigaction * act, + struct sigaction * oact) +{ + struct sigaction newact; + struct sigaction *newactp; + +printf(__FUNCTION__": pthreads wrapper!\n"); + if (sig == __pthread_sig_restart || + sig == __pthread_sig_cancel || + (sig == __pthread_sig_debug && __pthread_sig_debug > 0)) + return EINVAL; + if (act) + { + newact = *act; + if (act->sa_handler != SIG_IGN && act->sa_handler != SIG_DFL + && sig > 0 && sig < NSIG) + { + if (act->sa_flags & SA_SIGINFO) + newact.sa_handler = (__sighandler_t) pthread_sighandler_rt; + else + newact.sa_handler = (__sighandler_t) pthread_sighandler; + } + newactp = &newact; + } + else + newactp = NULL; + if (__libc_sigaction(sig, newactp, oact) == -1) + return -1; +printf(__FUNCTION__": signahdler installed, __sigaction successful\n"); + if (sig > 0 && sig < NSIG) + { + if (oact != NULL) + oact->sa_handler = (__sighandler_t) sighandler[sig].old; + if (act) + /* For the assignment is does not matter whether it's a normal + or real-time signal. */ + sighandler[sig].old = (arch_sighandler_t) act->sa_handler; + } + return 0; +} + +/* A signal handler that does nothing */ +static void pthread_null_sighandler(int sig) { } + +/* sigwait -- synchronously wait for a signal */ +int sigwait(const sigset_t * set, int * sig) +{ + volatile pthread_descr self = thread_self(); + sigset_t mask; + int s; + sigjmp_buf jmpbuf; + struct sigaction sa; + + /* Get ready to block all signals except those in set + and the cancellation signal. + Also check that handlers are installed on all signals in set, + and if not, install our dummy handler. This is conformant to + POSIX: "The effect of sigwait() on the signal actions for the + signals in set is unspecified." */ + sigfillset(&mask); + sigdelset(&mask, __pthread_sig_cancel); + for (s = 1; s <= NSIG; s++) { + if (sigismember(set, s) && + s != __pthread_sig_restart && + s != __pthread_sig_cancel && + s != __pthread_sig_debug) { + sigdelset(&mask, s); + if (sighandler[s].old == NULL || + sighandler[s].old == (arch_sighandler_t) SIG_DFL || + sighandler[s].old == (arch_sighandler_t) SIG_IGN) { + sa.sa_handler = pthread_null_sighandler; + sigemptyset(&sa.sa_mask); + sa.sa_flags = 0; + sigaction(s, &sa, NULL); + } + } + } + /* Test for cancellation */ + if (sigsetjmp(jmpbuf, 1) == 0) { + THREAD_SETMEM(self, p_cancel_jmp, &jmpbuf); + if (! (THREAD_GETMEM(self, p_canceled) + && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE)) { + /* Reset the signal count */ + THREAD_SETMEM(self, p_signal, 0); + /* Say we're in sigwait */ + THREAD_SETMEM(self, p_sigwaiting, 1); + /* Unblock the signals and wait for them */ + sigsuspend(&mask); + } + } + THREAD_SETMEM(self, p_cancel_jmp, NULL); + /* The signals are now reblocked. Check for cancellation */ + pthread_testcancel(); + /* We should have self->p_signal != 0 and equal to the signal received */ + *sig = THREAD_GETMEM(self, p_signal); + return 0; +} + +/* Redefine raise() to send signal to calling thread only, + as per POSIX 1003.1c */ +int raise (int sig) +{ + int retcode = pthread_kill(pthread_self(), sig); + if (retcode == 0) + return 0; + else { + errno = retcode; + return -1; + } +} |