signal.c

优龙2410linux2.6.8内核源代码

/*
 *  linux/arch/h8300/kernel/signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

/*
 * uClinux H8/300 support by Yoshinori Sato <[e-mail]>
 *                and David McCullough <[e-mail]>
 *
 * Based on
 * Linux/m68k by Hamish Macdonald
 */

/*
 * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
 * Atari :-) Current limitation: Only one sigstack can be active at one time.
 * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
 * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
 * signal handlers!
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/binfmts.h>

#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/ucontext.h>

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs);

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
asmlinkage int do_sigsuspend(struct pt_regs *regs)
{
	old_sigset_t mask = regs->er3;
	sigset_t saveset;

	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	regs->er0 = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, regs))
			return -EINTR;
	}
}

asmlinkage int
do_rt_sigsuspend(struct pt_regs *regs)
{
	sigset_t *unewset = (sigset_t *)regs->er1;
	size_t sigsetsize = (size_t)regs->er2;
	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(&current->sighand->siglock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	regs->er0 = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, regs))
			return -EINTR;
	}
}

asmlinkage int 
sys_sigaction(int sig, const struct old_sigaction *act,
	      struct old_sigaction *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	if (act) {
		old_sigset_t mask;
		if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
			return -EFAULT;
		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
		__get_user(mask, &act->sa_mask);
		siginitset(&new_ka.sa.sa_mask, mask);
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
			return -EFAULT;
		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	}

	return ret;
}

asmlinkage int
sys_sigaltstack(const stack_t *uss, stack_t *uoss)
{
	return do_sigaltstack(uss, uoss, rdusp());
}


/*
 * Do a signal return; undo the signal stack.
 *
 * Keep the return code on the stack quadword aligned!
 * That makes the cache flush below easier.
 */

struct sigframe
{
	long dummy_er0;
	long dummy_vector;
#if defined(CONFIG_CPU_H8S)
	short dummy_exr;
#endif
	long dummy_pc;
	char *pretcode;
	unsigned char retcode[8];
	unsigned long extramask[_NSIG_WORDS-1];
	struct sigcontext sc;
} __attribute__((aligned(2),packed));

struct rt_sigframe
{
	long dummy_er0;
	long dummy_vector;
#if defined(CONFIG_CPU_H8S)
	short dummy_exr;
#endif
	long dummy_pc;
	char *pretcode;
	unsigned char retcode[8];
	struct siginfo info;
	struct ucontext uc;
} __attribute__((aligned(2),packed));

static inline int
restore_sigcontext(struct pt_regs *regs, struct sigcontext *usc, void *fp,
		   int *pd0)
{
	struct sigcontext context;
	int err = 0;

	/* get previous context */
	if (copy_from_user(&context, usc, sizeof(context)))
		goto badframe;
	
	/* restore passed registers */
	regs->er1 = context.sc_er1;
	regs->er2 = context.sc_er2;
	regs->er3 = context.sc_er3;
	regs->er5 = context.sc_er5;
	regs->ccr = (regs->ccr & 0x10)|(context.sc_ccr & 0xef);
	regs->pc = context.sc_pc;
	regs->orig_er0 = -1;		/* disable syscall checks */
	wrusp(context.sc_usp);

	*pd0 = context.sc_er0;
	return err;

badframe:
	return 1;
}

static inline int
rt_restore_ucontext(struct pt_regs *regs, struct ucontext *uc, int *pd0)
{
	int temp;
	greg_t *gregs = uc->uc_mcontext.gregs;
	unsigned long usp;
	int err;

	err = __get_user(temp, &uc->uc_mcontext.version);
	if (temp != MCONTEXT_VERSION)
		goto badframe;
	/* restore passed registers */
	err |= __get_user(regs->er0, &gregs[0]);
	err |= __get_user(regs->er1, &gregs[1]);
	err |= __get_user(regs->er2, &gregs[2]);
	err |= __get_user(regs->er3, &gregs[3]);
	err |= __get_user(regs->er4, &gregs[4]);
	err |= __get_user(regs->er5, &gregs[5]);
	err |= __get_user(regs->er6, &gregs[6]);
	err |= __get_user(usp, &gregs[7]);
	wrusp(usp);
	err |= __get_user(regs->pc, &gregs[8]);
	err |= __get_user(temp, &gregs[9]);
	regs->ccr = (regs->ccr & 0x10) | (temp & 0xef);
	regs->orig_er0 = -1;		/* disable syscall checks */

	if (do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT)
		goto badframe;

	*pd0 = regs->er0;
	return err;

badframe:
	return 1;
}

asmlinkage int do_sigreturn(unsigned long __unused,...)
{
	struct pt_regs *regs = (struct pt_regs *) (&__unused - 1);
	unsigned long usp = rdusp();
	struct sigframe *frame = (struct sigframe *)(usp - 4);
	sigset_t set;
	int er0;

	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
	    (_NSIG_WORDS > 1 &&
	     __copy_from_user(&set.sig[1], &frame->extramask,
			      sizeof(frame->extramask))))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	
	if (restore_sigcontext(regs, &frame->sc, frame + 1, &er0))
		goto badframe;
	return er0;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

asmlinkage int do_rt_sigreturn(unsigned long __unused,...)
{
	struct pt_regs *regs = (struct pt_regs *) &__unused;
	unsigned long usp = rdusp();
	struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
	sigset_t set;
	int er0;

	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_unlock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_lock_irq(&current->sighand->siglock);
	
	if (rt_restore_ucontext(regs, &frame->uc, &er0))
		goto badframe;
	return er0;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

static void setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
			     unsigned long mask)
{
	sc->sc_mask = mask;
	sc->sc_usp = rdusp();
	sc->sc_er0 = regs->er0;
	sc->sc_er1 = regs->er1;
	sc->sc_er2 = regs->er2;
	sc->sc_er3 = regs->er3;
	sc->sc_er5 = regs->er5;
	sc->sc_ccr = regs->ccr;
	sc->sc_pc = regs->pc;
}

static inline int rt_setup_ucontext(struct ucontext *uc, struct pt_regs *regs)
{
	greg_t *gregs = uc->uc_mcontext.gregs;
	int err = 0;

	err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);