/*
* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#include "linux/config.h"
#include "linux/stddef.h"
#include "linux/sys.h"
#include "linux/sched.h"
#include "linux/wait.h"
#include "linux/kernel.h"
#include "linux/smp_lock.h"
#include "linux/module.h"
#include "linux/slab.h"
#include "linux/tty.h"
#include "linux/binfmts.h"
#include "linux/ptrace.h"
#include "asm/signal.h"
#include "asm/uaccess.h"
#include "asm/unistd.h"
#include "user_util.h"
#include "asm/ucontext.h"
#include "kern_util.h"
#include "signal_kern.h"
#include "kern.h"
#include "frame_kern.h"
#include "sigcontext.h"
#include "mode.h"
EXPORT_SYMBOL(block_signals);
EXPORT_SYMBOL(unblock_signals);
#define _S(nr) (1<<((nr)-1))
#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
/*
* OK, we're invoking a handler
*/
static int handle_signal(struct pt_regs *regs, unsigned long signr,
struct k_sigaction *ka, siginfo_t *info,
sigset_t *oldset)
{
unsigned long sp;
int err;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
/* Did we come from a system call? */
if(PT_REGS_SYSCALL_NR(regs) >= 0){
/* If so, check system call restarting.. */
switch(PT_REGS_SYSCALL_RET(regs)){
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
PT_REGS_SYSCALL_RET(regs) = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
PT_REGS_SYSCALL_RET(regs) = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
PT_REGS_RESTART_SYSCALL(regs);
PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
break;
}
}
sp = PT_REGS_SP(regs);
if((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
sp = current->sas_ss_sp + current->sas_ss_size;
#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
if(!(ka->sa.sa_flags & SA_SIGINFO))
err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
else
#endif
err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
if(err){
spin_lock_irq(¤t->sighand->siglock);
current->blocked = *oldset;
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
force_sigsegv(signr, current);
} else {
spin_lock_irq(¤t->sighand->siglock);
sigorsets(¤t->blocked, ¤t->blocked,
&ka->sa.sa_mask);
if(!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(¤t->blocked, signr);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
}
return err;
}
static int kern_do_signal(struct pt_regs *regs, sigset_t *oldset)
{
struct k_sigaction ka_copy;
siginfo_t info;
int sig, handled_sig = 0;
while((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0){
handled_sig = 1;
/* Whee! Actually deliver the signal. */
if(!handle_signal(regs, sig, &ka_copy, &info, oldset))
break;
}
/* Did we come from a system call? */
if(!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)){
/* Restart the system call - no handlers present */
if(PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOHAND ||
PT_REGS_SYSCALL_RET(regs) == -ERESTARTSYS ||
PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOINTR){
PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
PT_REGS_RESTART_SYSCALL(regs);
}
else if(PT_REGS_SYSCALL_RET(regs) == -ERESTART_RESTARTBLOCK){
PT_REGS_SYSCALL_RET(regs) = __NR_restart_syscall;
PT_REGS_RESTART_SYSCALL(regs);
}
}
/* This closes a way to execute a system call on the host. If
* you set a breakpoint on a system call instruction and singlestep
* from it, the tracing thread used to PTRACE_SINGLESTEP the process
* rather than PTRACE_SYSCALL it, allowing the system call to execute
* on the host. The tracing thread will check this flag and
* PTRACE_SYSCALL if necessary.
*/
if(current->ptrace & PT_DTRACE)
current->thread.singlestep_syscall =
is_syscall(PT_REGS_IP(¤t->thread.regs));
return(handled_sig);
}
int do_signal(void)
{
return(kern_do_signal(¤t->thread.regs, ¤t->blocked));
}
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
{
sigset_t saveset;
mask &= _BLOCKABLE;
spin_lock_irq(¤t->sighand->siglock);
saveset = current->blocked;
siginitset(¤t->blocked, mask);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
PT_REGS_SYSCALL_RET(¤t->thread.regs) = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if(kern_do_signal(¤t->thread.regs, &saveset))
return(-EINTR);
}
}
long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
{
sigset_t saveset, newset;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&newset, unewset, sizeof(newset)))
return -EFAULT;
sigdelsetmask(&newset, ~_BLOCKABLE);
spin_lock_irq(¤t->sighand->siglock);
saveset = current->blocked;
current->blocked = newset;
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
PT_REGS_SYSCALL_RET(¤t->thread.regs) = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (kern_do_signal(¤t->thread.regs, &saveset))
return(-EINTR);
}
}
long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
return(do_sigaltstack(uss, uoss, PT_REGS_SP(¤t->thread.regs)));
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
