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/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <asm/siginfo.h>
#include <asm/signal.h>
#include <asm/unistd.h>
#include <frame_kern.h>
#include <kern_util.h>
EXPORT_SYMBOL(block_signals);
EXPORT_SYMBOL(unblock_signals);
/*
* OK, we're invoking a handler
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int singlestep = 0;
unsigned long sp;
int err;
if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
singlestep = 1;
/* 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 (!(ksig->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 ((ksig->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 (!(ksig->ka.sa.sa_flags & SA_SIGINFO))
err = setup_signal_stack_sc(sp, ksig, regs, oldset);
else
#endif
err = setup_signal_stack_si(sp, ksig, regs, oldset);
signal_setup_done(err, ksig, singlestep);
}
void do_signal(struct pt_regs *regs)
{
struct ksignal ksig;
int handled_sig = 0;
if (get_signal(&ksig)) {
handled_sig = 1;
/* Whee! Actually deliver the signal. */
handle_signal(&ksig, regs);
}
/* Did we come from a system call? */
if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
/* Restart the system call - no handlers present */
switch (PT_REGS_SYSCALL_RET(regs)) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
PT_REGS_RESTART_SYSCALL(regs);
break;
case -ERESTART_RESTARTBLOCK:
PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
PT_REGS_RESTART_SYSCALL(regs);
break;
}
}
/*
* 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));
/*
* if there's no signal to deliver, we just put the saved sigmask
* back
*/
if (!handled_sig)
restore_saved_sigmask();
}
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