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/*
* linux/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <asm/segment.h>
#define _S(nr) (1<<((nr)-1))
#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
asmlinkage int sys_sigprocmask(int how, sigset_t *set, sigset_t *oset)
{
sigset_t new_set, old_set = current->blocked;
int error;
if (set) {
error = verify_area(VERIFY_READ, set, sizeof(sigset_t));
if (error)
return error;
new_set = get_fs_long((unsigned long *) set) & _BLOCKABLE;
switch (how) {
case SIG_BLOCK:
current->blocked |= new_set;
break;
case SIG_UNBLOCK:
current->blocked &= ~new_set;
break;
case SIG_SETMASK:
current->blocked = new_set;
break;
default:
return -EINVAL;
}
}
if (oset) {
error = verify_area(VERIFY_WRITE, oset, sizeof(sigset_t));
if (error)
return error;
put_fs_long(old_set, (unsigned long *) oset);
}
return 0;
}
asmlinkage int sys_sgetmask(void)
{
return current->blocked;
}
asmlinkage int sys_ssetmask(int newmask)
{
int old=current->blocked;
current->blocked = newmask & _BLOCKABLE;
return old;
}
asmlinkage int sys_sigpending(sigset_t *set)
{
int error;
/* fill in "set" with signals pending but blocked. */
error = verify_area(VERIFY_WRITE, set, 4);
if (!error)
put_fs_long(current->blocked & current->signal, (unsigned long *)set);
return error;
}
/*
* POSIX 3.3.1.3:
* "Setting a signal action to SIG_IGN for a signal that is pending
* shall cause the pending signal to be discarded, whether or not
* it is blocked" (but SIGCHLD is unspecified: linux leaves it alone).
*
* "Setting a signal action to SIG_DFL for a signal that is pending
* and whose default action is to ignore the signal (for example,
* SIGCHLD), shall cause the pending signal to be discarded, whether
* or not it is blocked"
*
* Note the silly behaviour of SIGCHLD: SIG_IGN means that the signal
* isn't actually ignored, but does automatic child reaping, while
* SIG_DFL is explicitly said by POSIX to force the signal to be ignored..
*/
static void check_pending(int signum)
{
struct sigaction *p;
p = signum - 1 + current->sigaction;
if (p->sa_handler == SIG_IGN) {
if (signum == SIGCHLD)
return;
current->signal &= ~_S(signum);
return;
}
if (p->sa_handler == SIG_DFL) {
if (signum != SIGCONT && signum != SIGCHLD && signum != SIGWINCH)
return;
current->signal &= ~_S(signum);
return;
}
}
asmlinkage unsigned long sys_signal(int signum, void (*handler)(int))
{
int err;
struct sigaction tmp;
if (signum<1 || signum>32)
return -EINVAL;
if (signum==SIGKILL || signum==SIGSTOP)
return -EINVAL;
if (handler != SIG_DFL && handler != SIG_IGN) {
err = verify_area(VERIFY_READ, handler, 1);
if (err)
return err;
}
tmp.sa_handler = handler;
tmp.sa_mask = 0;
tmp.sa_flags = SA_ONESHOT | SA_NOMASK;
tmp.sa_restorer = NULL;
handler = current->sigaction[signum-1].sa_handler;
current->sigaction[signum-1] = tmp;
check_pending(signum);
return (unsigned long) handler;
}
asmlinkage int sys_sigaction(int signum, const struct sigaction * action,
struct sigaction * oldaction)
{
struct sigaction new_sa, *p;
if (signum<1 || signum>32)
return -EINVAL;
if (signum==SIGKILL || signum==SIGSTOP)
return -EINVAL;
p = signum - 1 + current->sigaction;
if (action) {
int err = verify_area(VERIFY_READ, action, sizeof(*action));
if (err)
return err;
memcpy_fromfs(&new_sa, action, sizeof(struct sigaction));
if (new_sa.sa_flags & SA_NOMASK)
new_sa.sa_mask = 0;
else {
new_sa.sa_mask |= _S(signum);
new_sa.sa_mask &= _BLOCKABLE;
}
if (new_sa.sa_handler != SIG_DFL && new_sa.sa_handler != SIG_IGN) {
err = verify_area(VERIFY_READ, new_sa.sa_handler, 1);
if (err)
return err;
}
}
if (oldaction) {
int err = verify_area(VERIFY_WRITE, oldaction, sizeof(*oldaction));
if (err)
return err;
memcpy_tofs(oldaction, p, sizeof(struct sigaction));
}
if (action) {
*p = new_sa;
check_pending(signum);
}
return 0;
}
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