/* * 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); } static int kern_do_signal(struct pt_regs *regs) { struct ksignal ksig; int handled_sig = 0; while (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(); return handled_sig; } int do_signal(void) { return kern_do_signal(¤t->thread.regs); }