43fe67e2f9
* lib/linux/read.c (read): Add casts. * lib/linux/signal.c (signal): Likewise. * lib/stdio/vfscanf.c: Include stdlib.h. (vfscanf): Add cast. * lib/stdlib/mbstowcs.c (mbstowcs): Add cast.
73 lines
2.5 KiB
C
73 lines
2.5 KiB
C
/* -*-comment-start: "//";comment-end:""-*-
|
|
* GNU Mes --- Maxwell Equations of Software
|
|
* Copyright © 2018,2019,2022,2023 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
|
|
*
|
|
* This file is part of GNU Mes.
|
|
*
|
|
* GNU Mes is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 3 of the License, or (at
|
|
* your option) any later version.
|
|
*
|
|
* GNU Mes 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 General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with GNU Mes. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <linux/syscall.h>
|
|
#include <arch/syscall.h>
|
|
#include <unistd.h>
|
|
#include <signal.h>
|
|
|
|
#if __i386__
|
|
#else
|
|
void
|
|
_restorer_for_siginfo (void)
|
|
{
|
|
_sys_call (SYS_rt_sigreturn);
|
|
}
|
|
#endif
|
|
|
|
sighandler_t
|
|
signal (int signum, sighandler_t action)
|
|
{
|
|
#if __i386__
|
|
return (sighandler_t) _sys_call2 (SYS_signal, signum, (long) action);
|
|
#else
|
|
static struct sigaction setup_action = { 0 };
|
|
static struct sigaction old = { 0 };
|
|
unsigned short bitindex;
|
|
unsigned short itembitcount;
|
|
|
|
setup_action.sa_handler = action;
|
|
/* The sa_restorer is not used. Reason:
|
|
* The kernel uses its own restorer anyway by pretending we gave one on
|
|
our side (no, really).
|
|
glibc still has a custom restorer because they want to be able to
|
|
backtrace. gdb has a second part that detects a specific instruction
|
|
sequence and then fixes up the backtrace. Since we don't use that
|
|
specific instruction sequence and also the non-siginfo restorer
|
|
is complicated (pops foreign item off the stack--so needs inline
|
|
assembly) and we don't support great debuggability in other places,
|
|
I've decided to take the easy way out for now. */
|
|
/*setup_action.sa_restorer = _restorer_for_siginfo;*/
|
|
bitindex = signum - 1;
|
|
itembitcount = 8 * sizeof (setup_action.sa_mask.items[0]);
|
|
setup_action.sa_mask.items[bitindex / itembitcount] = 1UL << (bitindex % itembitcount);
|
|
old.sa_handler = SIG_DFL;
|
|
setup_action.sa_flags = SA_RESTART;
|
|
#if __x86_64__
|
|
/* Tell kernel that we use a restorer, on penalty of segfault. */
|
|
setup_action.sa_flags |= SA_RESTORER;
|
|
#endif
|
|
int r = _sys_call4 (SYS_rt_sigaction, signum, (long) &setup_action, (long) &old, sizeof (sigset_t));
|
|
if (r)
|
|
return 0;
|
|
return old.sa_handler;
|
|
#endif
|
|
}
|