diff options
Diffstat (limited to 'REORG.TODO/hurd/catch-signal.c')
| -rw-r--r-- | REORG.TODO/hurd/catch-signal.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/REORG.TODO/hurd/catch-signal.c b/REORG.TODO/hurd/catch-signal.c new file mode 100644 index 0000000000..1d606ecaf0 --- /dev/null +++ b/REORG.TODO/hurd/catch-signal.c @@ -0,0 +1,167 @@ +/* Convenience function to catch expected signals during an operation. + Copyright (C) 1996-2017 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 Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#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) +{ + /* We need to restore the signal mask, because otherwise the + signal-handling code will have blocked the caught signal and for + instance calling hurd_catch_signal again would then dump core. */ + sigjmp_buf buf; + void throw (int signo, long int sigcode, struct sigcontext *scp) + { siglongjmp (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 = sigsetjmp (buf, 1); + + 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; +} |