/* Convenience function to catch expected signals during an operation. Copyright (C) 1996 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library 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. The GNU C Library 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. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <hurd/signal.h> #include <hurd/sigpreempt.h> #include <string.h> #include <assert.h> error_t hurd_catch_signal (sigset_t sigset, unsigned long int first, unsigned long int last, error_t (*operate) (struct hurd_signal_preemptor *), sighandler_t handler) { jmp_buf buf; void throw (int signo, long int sigcode, struct sigcontext *scp) { longjmp (buf, scp->sc_error ?: EGRATUITOUS); } struct hurd_signal_preemptor preemptor = { sigset, first, last, NULL, handler == SIG_ERR ? (sighandler_t) &throw : handler, }; struct hurd_sigstate *const ss = _hurd_self_sigstate (); error_t error; if (handler == SIG_ERR) /* Not our handler; don't bother saving state. */ error = 0; else /* This returns again with nonzero value when we preempt a signal. */ error = setjmp (buf); if (error == 0) { /* Install a signal preemptor for the thread. */ __spin_lock (&ss->lock); preemptor.next = ss->preemptors; ss->preemptors = &preemptor; __spin_unlock (&ss->lock); /* Try the operation that might crash. */ (*operate) (&preemptor); } /* Either FUNCTION completed happily and ERROR is still zero, or it hit an expected signal and `throw' made setjmp return the signal error code in ERROR. Now we can remove the preemptor and return. */ __spin_lock (&ss->lock); assert (ss->preemptors == &preemptor); ss->preemptors = preemptor.next; __spin_unlock (&ss->lock); return error; } error_t hurd_safe_memset (void *dest, int byte, size_t nbytes) { error_t operate (struct hurd_signal_preemptor *preemptor) { memset (dest, byte, nbytes); return 0; } return hurd_catch_signal (sigmask (SIGBUS) | sigmask (SIGSEGV), (vm_address_t) dest, (vm_address_t) dest + nbytes, &operate, SIG_ERR); } error_t hurd_safe_copyout (void *dest, const void *src, size_t nbytes) { error_t operate (struct hurd_signal_preemptor *preemptor) { memcpy (dest, src, nbytes); return 0; } return hurd_catch_signal (sigmask (SIGBUS) | sigmask (SIGSEGV), (vm_address_t) dest, (vm_address_t) dest + nbytes, &operate, SIG_ERR); } error_t hurd_safe_copyin (void *dest, const void *src, size_t nbytes) { error_t operate (struct hurd_signal_preemptor *preemptor) { memcpy (dest, src, nbytes); return 0; } return hurd_catch_signal (sigmask (SIGBUS) | sigmask (SIGSEGV), (vm_address_t) src, (vm_address_t) src + nbytes, &operate, SIG_ERR); } error_t hurd_safe_memmove (void *dest, const void *src, size_t nbytes) { jmp_buf buf; void throw (int signo, long int sigcode, struct sigcontext *scp) { longjmp (buf, scp->sc_error ?: EGRATUITOUS); } struct hurd_signal_preemptor src_preemptor = { sigmask (SIGBUS) | sigmask (SIGSEGV), (vm_address_t) src, (vm_address_t) src + nbytes, NULL, (sighandler_t) &throw, }; struct hurd_signal_preemptor dest_preemptor = { sigmask (SIGBUS) | sigmask (SIGSEGV), (vm_address_t) dest, (vm_address_t) dest + nbytes, NULL, (sighandler_t) &throw, &src_preemptor }; struct hurd_sigstate *const ss = _hurd_self_sigstate (); error_t error; /* This returns again with nonzero value when we preempt a signal. */ error = setjmp (buf); if (error == 0) { /* Install a signal preemptor for the thread. */ __spin_lock (&ss->lock); src_preemptor.next = ss->preemptors; ss->preemptors = &dest_preemptor; __spin_unlock (&ss->lock); /* Do the copy; it might fault. */ memmove (dest, src, nbytes); } /* Either memmove completed happily and ERROR is still zero, or it hit an expected signal and `throw' made setjmp return the signal error code in ERROR. Now we can remove the preemptor and return. */ __spin_lock (&ss->lock); assert (ss->preemptors == &dest_preemptor); ss->preemptors = src_preemptor.next; __spin_unlock (&ss->lock); return error; }