69be8f1896
It has been reported that the way Linux handles NODEFER for signals is not consistent with the way other Unix boxes handle it. I've written a program to test the behavior of how this flag affects signals and had several reports from people who ran this on various Unix boxes, confirming that Linux seems to be unique on the way this is handled. The way NODEFER affects signals on other Unix boxes is as follows: 1) If NODEFER is set, other signals in sa_mask are still blocked. 2) If NODEFER is set and the signal is in sa_mask, then the signal is still blocked. (Note: this is the behavior of all tested but Linux _and_ NetBSD 2.0 *). The way NODEFER affects signals on Linux: 1) If NODEFER is set, other signals are _not_ blocked regardless of sa_mask (Even NetBSD doesn't do this). 2) If NODEFER is set and the signal is in sa_mask, then the signal being handled is not blocked. The patch converts signal handling in all current Linux architectures to the way most Unix boxes work. Unix boxes that were tested: DU4, AIX 5.2, Irix 6.5, NetBSD 2.0, SFU 3.5 on WinXP, AIX 5.3, Mac OSX, and of course Linux 2.6.13-rcX. * NetBSD was the only other Unix to behave like Linux on point #2. The main concern was brought up by point #1 which even NetBSD isn't like Linux. So with this patch, we leave NetBSD as the lonely one that behaves differently here with #2. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
539 lines
15 KiB
C
539 lines
15 KiB
C
/*
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* linux/arch/arm26/kernel/signal.c
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*
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* Copyright (C) 1995-2002 Russell King
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* Copyright (C) 2003 Ian Molton (ARM26)
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*
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* FIXME!!! This is probably very broken (13/05/2003)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/config.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/wait.h>
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#include <linux/ptrace.h>
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#include <linux/personality.h>
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#include <linux/tty.h>
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#include <linux/binfmts.h>
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#include <linux/elf.h>
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#include <asm/pgalloc.h>
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#include <asm/ucontext.h>
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#include <asm/uaccess.h>
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#include <asm/unistd.h>
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#include "ptrace.h"
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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
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/*
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* For ARM syscalls, we encode the syscall number into the instruction.
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*/
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#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn))
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#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn))
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static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
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/*
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* atomically swap in the new signal mask, and wait for a signal.
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*/
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asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs)
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{
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sigset_t saveset;
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mask &= _BLOCKABLE;
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spin_lock_irq(¤t->sighand->siglock);
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saveset = current->blocked;
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siginitset(¤t->blocked, mask);
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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regs->ARM_r0 = -EINTR;
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while (1) {
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current->state = TASK_INTERRUPTIBLE;
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schedule();
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if (do_signal(&saveset, regs, 0))
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return regs->ARM_r0;
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}
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}
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asmlinkage int
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sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, struct pt_regs *regs)
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{
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sigset_t saveset, newset;
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/* XXX: Don't preclude handling different sized sigset_t's. */
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if (sigsetsize != sizeof(sigset_t))
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return -EINVAL;
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if (copy_from_user(&newset, unewset, sizeof(newset)))
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return -EFAULT;
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sigdelsetmask(&newset, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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saveset = current->blocked;
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current->blocked = newset;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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regs->ARM_r0 = -EINTR;
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while (1) {
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current->state = TASK_INTERRUPTIBLE;
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schedule();
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if (do_signal(&saveset, regs, 0))
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return regs->ARM_r0;
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}
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}
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asmlinkage int
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sys_sigaction(int sig, const struct old_sigaction *act,
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struct old_sigaction *oact)
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{
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struct k_sigaction new_ka, old_ka;
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int ret;
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if (act) {
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old_sigset_t mask;
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if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
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__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
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__get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
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return -EFAULT;
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__get_user(new_ka.sa.sa_flags, &act->sa_flags);
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__get_user(mask, &act->sa_mask);
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siginitset(&new_ka.sa.sa_mask, mask);
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}
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ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
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if (!ret && oact) {
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if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
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__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
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__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
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return -EFAULT;
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__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
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__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
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}
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return ret;
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}
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/*
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* Do a signal return; undo the signal stack.
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*/
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struct sigframe
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{
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struct sigcontext sc;
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unsigned long extramask[_NSIG_WORDS-1];
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unsigned long retcode;
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};
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struct rt_sigframe
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{
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struct siginfo *pinfo;
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void *puc;
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struct siginfo info;
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struct ucontext uc;
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unsigned long retcode;
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};
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static int
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restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
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{
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int err = 0;
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__get_user_error(regs->ARM_r0, &sc->arm_r0, err);
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__get_user_error(regs->ARM_r1, &sc->arm_r1, err);
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__get_user_error(regs->ARM_r2, &sc->arm_r2, err);
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__get_user_error(regs->ARM_r3, &sc->arm_r3, err);
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__get_user_error(regs->ARM_r4, &sc->arm_r4, err);
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__get_user_error(regs->ARM_r5, &sc->arm_r5, err);
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__get_user_error(regs->ARM_r6, &sc->arm_r6, err);
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__get_user_error(regs->ARM_r7, &sc->arm_r7, err);
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__get_user_error(regs->ARM_r8, &sc->arm_r8, err);
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__get_user_error(regs->ARM_r9, &sc->arm_r9, err);
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__get_user_error(regs->ARM_r10, &sc->arm_r10, err);
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__get_user_error(regs->ARM_fp, &sc->arm_fp, err);
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__get_user_error(regs->ARM_ip, &sc->arm_ip, err);
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__get_user_error(regs->ARM_sp, &sc->arm_sp, err);
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__get_user_error(regs->ARM_lr, &sc->arm_lr, err);
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__get_user_error(regs->ARM_pc, &sc->arm_pc, err);
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err |= !valid_user_regs(regs);
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return err;
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}
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asmlinkage int sys_sigreturn(struct pt_regs *regs)
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{
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struct sigframe *frame;
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sigset_t set;
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/*
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* Since we stacked the signal on a 64-bit boundary,
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* then 'sp' should be word aligned here. If it's
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* not, then the user is trying to mess with us.
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*/
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if (regs->ARM_sp & 7)
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goto badframe;
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frame = (struct sigframe *)regs->ARM_sp;
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if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
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goto badframe;
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if (__get_user(set.sig[0], &frame->sc.oldmask)
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|| (_NSIG_WORDS > 1
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&& __copy_from_user(&set.sig[1], &frame->extramask,
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sizeof(frame->extramask))))
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goto badframe;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigcontext(regs, &frame->sc))
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goto badframe;
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/* Send SIGTRAP if we're single-stepping */
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if (current->ptrace & PT_SINGLESTEP) {
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ptrace_cancel_bpt(current);
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send_sig(SIGTRAP, current, 1);
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}
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return regs->ARM_r0;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
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{
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struct rt_sigframe *frame;
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sigset_t set;
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/*
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* Since we stacked the signal on a 64-bit boundary,
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* then 'sp' should be word aligned here. If it's
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* not, then the user is trying to mess with us.
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*/
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if (regs->ARM_sp & 7)
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goto badframe;
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frame = (struct rt_sigframe *)regs->ARM_sp;
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if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
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goto badframe;
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
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goto badframe;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
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goto badframe;
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/* Send SIGTRAP if we're single-stepping */
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if (current->ptrace & PT_SINGLESTEP) {
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ptrace_cancel_bpt(current);
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send_sig(SIGTRAP, current, 1);
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}
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return regs->ARM_r0;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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static int
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setup_sigcontext(struct sigcontext *sc, /*struct _fpstate *fpstate,*/
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struct pt_regs *regs, unsigned long mask)
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{
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int err = 0;
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__put_user_error(regs->ARM_r0, &sc->arm_r0, err);
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__put_user_error(regs->ARM_r1, &sc->arm_r1, err);
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__put_user_error(regs->ARM_r2, &sc->arm_r2, err);
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__put_user_error(regs->ARM_r3, &sc->arm_r3, err);
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__put_user_error(regs->ARM_r4, &sc->arm_r4, err);
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__put_user_error(regs->ARM_r5, &sc->arm_r5, err);
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__put_user_error(regs->ARM_r6, &sc->arm_r6, err);
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__put_user_error(regs->ARM_r7, &sc->arm_r7, err);
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__put_user_error(regs->ARM_r8, &sc->arm_r8, err);
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__put_user_error(regs->ARM_r9, &sc->arm_r9, err);
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__put_user_error(regs->ARM_r10, &sc->arm_r10, err);
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__put_user_error(regs->ARM_fp, &sc->arm_fp, err);
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__put_user_error(regs->ARM_ip, &sc->arm_ip, err);
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__put_user_error(regs->ARM_sp, &sc->arm_sp, err);
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__put_user_error(regs->ARM_lr, &sc->arm_lr, err);
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__put_user_error(regs->ARM_pc, &sc->arm_pc, err);
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__put_user_error(current->thread.trap_no, &sc->trap_no, err);
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__put_user_error(current->thread.error_code, &sc->error_code, err);
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__put_user_error(current->thread.address, &sc->fault_address, err);
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__put_user_error(mask, &sc->oldmask, err);
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return err;
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}
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static inline void *
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get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
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{
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unsigned long sp = regs->ARM_sp;
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/*
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* This is the X/Open sanctioned signal stack switching.
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*/
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if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
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sp = current->sas_ss_sp + current->sas_ss_size;
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/*
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* ATPCS B01 mandates 8-byte alignment
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*/
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return (void *)((sp - framesize) & ~7);
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}
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static int
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setup_return(struct pt_regs *regs, struct k_sigaction *ka,
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unsigned long *rc, void *frame, int usig)
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{
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unsigned long handler = (unsigned long)ka->sa.sa_handler;
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unsigned long retcode;
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if (ka->sa.sa_flags & SA_RESTORER) {
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retcode = (unsigned long)ka->sa.sa_restorer;
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} else {
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if (__put_user((ka->sa.sa_flags & SA_SIGINFO)?SWI_SYS_RT_SIGRETURN:SWI_SYS_SIGRETURN, rc))
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return 1;
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retcode = ((unsigned long)rc);
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}
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regs->ARM_r0 = usig;
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regs->ARM_sp = (unsigned long)frame;
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regs->ARM_lr = retcode;
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regs->ARM_pc = handler & ~3;
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return 0;
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}
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static int
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setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
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{
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struct sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
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int err = 0;
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if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
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return 1;
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err |= setup_sigcontext(&frame->sc, /*&frame->fpstate,*/ regs, set->sig[0]);
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if (_NSIG_WORDS > 1) {
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err |= __copy_to_user(frame->extramask, &set->sig[1],
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sizeof(frame->extramask));
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}
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if (err == 0)
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err = setup_return(regs, ka, &frame->retcode, frame, usig);
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return err;
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}
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static int
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setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *set, struct pt_regs *regs)
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{
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struct rt_sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
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int err = 0;
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if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
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return 1;
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__put_user_error(&frame->info, &frame->pinfo, err);
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__put_user_error(&frame->uc, &frame->puc, err);
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err |= copy_siginfo_to_user(&frame->info, info);
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/* Clear all the bits of the ucontext we don't use. */
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err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
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err |= setup_sigcontext(&frame->uc.uc_mcontext, /*&frame->fpstate,*/
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regs, set->sig[0]);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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if (err == 0)
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err = setup_return(regs, ka, &frame->retcode, frame, usig);
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if (err == 0) {
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/*
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* For realtime signals we must also set the second and third
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* arguments for the signal handler.
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* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
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*/
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regs->ARM_r1 = (unsigned long)frame->pinfo;
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regs->ARM_r2 = (unsigned long)frame->puc;
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}
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return err;
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}
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static inline void restart_syscall(struct pt_regs *regs)
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{
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regs->ARM_r0 = regs->ARM_ORIG_r0;
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regs->ARM_pc -= 4;
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}
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/*
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* OK, we're invoking a handler
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*/
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static void
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handle_signal(unsigned long sig, siginfo_t *info, sigset_t *oldset,
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struct pt_regs * regs, int syscall)
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{
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struct thread_info *thread = current_thread_info();
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struct task_struct *tsk = current;
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struct k_sigaction *ka = &tsk->sighand->action[sig-1];
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int usig = sig;
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int ret;
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/*
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* If we were from a system call, check for system call restarting...
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*/
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if (syscall) {
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switch (regs->ARM_r0) {
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case -ERESTART_RESTARTBLOCK:
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current_thread_info()->restart_block.fn =
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do_no_restart_syscall;
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case -ERESTARTNOHAND:
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regs->ARM_r0 = -EINTR;
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break;
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case -ERESTARTSYS:
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if (!(ka->sa.sa_flags & SA_RESTART)) {
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regs->ARM_r0 = -EINTR;
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break;
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}
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/* fallthrough */
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case -ERESTARTNOINTR:
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restart_syscall(regs);
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}
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}
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/*
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* translate the signal
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*/
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if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
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usig = thread->exec_domain->signal_invmap[usig];
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/*
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* Set up the stack frame
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*/
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if (ka->sa.sa_flags & SA_SIGINFO)
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ret = setup_rt_frame(usig, ka, info, oldset, regs);
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else
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ret = setup_frame(usig, ka, oldset, regs);
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/*
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* Check that the resulting registers are actually sane.
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*/
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ret |= !valid_user_regs(regs);
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if (ret == 0) {
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if (ka->sa.sa_flags & SA_ONESHOT)
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ka->sa.sa_handler = SIG_DFL;
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spin_lock_irq(&tsk->sighand->siglock);
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sigorsets(&tsk->blocked, &tsk->blocked,
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&ka->sa.sa_mask);
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if (!(ka->sa.sa_flags & SA_NODEFER))
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sigaddset(&tsk->blocked, sig);
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recalc_sigpending();
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spin_unlock_irq(&tsk->sighand->siglock);
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return;
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}
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force_sigsegv(sig, tsk);
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}
|
|
|
|
/*
|
|
* Note that 'init' is a special process: it doesn't get signals it doesn't
|
|
* want to handle. Thus you cannot kill init even with a SIGKILL even by
|
|
* mistake.
|
|
*
|
|
* Note that we go through the signals twice: once to check the signals that
|
|
* the kernel can handle, and then we build all the user-level signal handling
|
|
* stack-frames in one go after that.
|
|
*/
|
|
static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
|
|
{
|
|
siginfo_t info;
|
|
int signr;
|
|
|
|
/*
|
|
* We want the common case to go fast, which
|
|
* is why we may in certain cases get here from
|
|
* kernel mode. Just return without doing anything
|
|
* if so.
|
|
*/
|
|
if (!user_mode(regs))
|
|
return 0;
|
|
|
|
if (current->ptrace & PT_SINGLESTEP)
|
|
ptrace_cancel_bpt(current);
|
|
|
|
signr = get_signal_to_deliver(&info, regs, NULL);
|
|
if (signr > 0) {
|
|
handle_signal(signr, &info, oldset, regs, syscall);
|
|
if (current->ptrace & PT_SINGLESTEP)
|
|
ptrace_set_bpt(current);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* No signal to deliver to the process - restart the syscall.
|
|
*/
|
|
if (syscall) {
|
|
if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
|
|
u32 *usp;
|
|
|
|
regs->ARM_sp -= 12;
|
|
usp = (u32 *)regs->ARM_sp;
|
|
|
|
put_user(regs->ARM_pc, &usp[0]);
|
|
/* swi __NR_restart_syscall */
|
|
put_user(0xef000000 | __NR_restart_syscall, &usp[1]);
|
|
/* ldr pc, [sp], #12 */
|
|
// FIXME!!! is #12 correct there?
|
|
put_user(0xe49df00c, &usp[2]);
|
|
|
|
regs->ARM_pc = regs->ARM_sp + 4;
|
|
}
|
|
if (regs->ARM_r0 == -ERESTARTNOHAND ||
|
|
regs->ARM_r0 == -ERESTARTSYS ||
|
|
regs->ARM_r0 == -ERESTARTNOINTR) {
|
|
restart_syscall(regs);
|
|
}
|
|
}
|
|
if (current->ptrace & PT_SINGLESTEP)
|
|
ptrace_set_bpt(current);
|
|
return 0;
|
|
}
|
|
|
|
asmlinkage void
|
|
do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
|
|
{
|
|
if (thread_flags & _TIF_SIGPENDING)
|
|
do_signal(¤t->blocked, regs, syscall);
|
|
}
|