signal32.c

linux 内核源代码

		if (err)
			return -EFAULT;
	}

	set_fs(KERNEL_DS);
	ret = do_sigaltstack(uss ? (stack_t __user *)&kss : NULL,
			     uoss ? (stack_t __user *)&koss : NULL, usp);
	set_fs(old_fs);

	if (!ret && uoss) {
		if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
			return -EFAULT;
		sp = (int) (unsigned long) koss.ss_sp;
		err |= __put_user(sp, &uoss->ss_sp);
		err |= __put_user(koss.ss_size, &uoss->ss_size);
		err |= __put_user(koss.ss_flags, &uoss->ss_flags);
		if (err)
			return -EFAULT;
	}
	return ret;
}

int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
{
	int err;

	if (!access_ok (VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
		return -EFAULT;

	/* If you change siginfo_t structure, please be sure
	   this code is fixed accordingly.
	   It should never copy any pad contained in the structure
	   to avoid security leaks, but must copy the generic
	   3 ints plus the relevant union member.
	   This routine must convert siginfo from 64bit to 32bit as well
	   at the same time.  */
	err = __put_user(from->si_signo, &to->si_signo);
	err |= __put_user(from->si_errno, &to->si_errno);
	err |= __put_user((short)from->si_code, &to->si_code);
	if (from->si_code < 0)
		err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
	else {
		switch (from->si_code >> 16) {
		case __SI_TIMER >> 16:
			err |= __put_user(from->si_tid, &to->si_tid);
			err |= __put_user(from->si_overrun, &to->si_overrun);
			err |= __put_user(from->si_int, &to->si_int);
			break;
		case __SI_CHLD >> 16:
			err |= __put_user(from->si_utime, &to->si_utime);
			err |= __put_user(from->si_stime, &to->si_stime);
			err |= __put_user(from->si_status, &to->si_status);
		default:
			err |= __put_user(from->si_pid, &to->si_pid);
			err |= __put_user(from->si_uid, &to->si_uid);
			break;
		case __SI_FAULT >> 16:
			err |= __put_user((unsigned long)from->si_addr, &to->si_addr);
			break;
		case __SI_POLL >> 16:
			err |= __put_user(from->si_band, &to->si_band);
			err |= __put_user(from->si_fd, &to->si_fd);
			break;
		case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
		case __SI_MESGQ >> 16:
			err |= __put_user(from->si_pid, &to->si_pid);
			err |= __put_user(from->si_uid, &to->si_uid);
			err |= __put_user(from->si_int, &to->si_int);
			break;
		}
	}
	return err;
}

asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
{
	struct sigframe32 __user *frame;
	sigset_t blocked;
	int sig;

	frame = (struct sigframe32 __user *) regs.regs[29];
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_conv_sigset_from_user(&blocked, &frame->sf_mask))
		goto badframe;

	sigdelsetmask(&blocked, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = blocked;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	sig = restore_sigcontext32(&regs, &frame->sf_sc);
	if (sig < 0)
		goto badframe;
	else if (sig)
		force_sig(sig, current);

	/*
	 * Don't let your children do this ...
	 */
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tsyscall_exit"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}

asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
{
	struct rt_sigframe32 __user *frame;
	mm_segment_t old_fs;
	sigset_t set;
	stack_t st;
	s32 sp;
	int sig;

	frame = (struct rt_sigframe32 __user *) regs.regs[29];
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	sig = restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext);
	if (sig < 0)
		goto badframe;
	else if (sig)
		force_sig(sig, current);

	/* The ucontext contains a stack32_t, so we must convert!  */
	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
		goto badframe;
	st.ss_sp = (void __user *)(long) sp;
	if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
		goto badframe;
	if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
		goto badframe;

	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	old_fs = get_fs();
	set_fs(KERNEL_DS);
	do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
	set_fs(old_fs);

	/*
	 * Don't let your children do this ...
	 */
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tsyscall_exit"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}

static int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
	int signr, sigset_t *set)
{
	struct sigframe32 __user *frame;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
		goto give_sigsegv;

	err |= install_sigtramp(frame->sf_code, __NR_O32_sigreturn);

	err |= setup_sigcontext32(regs, &frame->sf_sc);
	err |= __copy_conv_sigset_to_user(&frame->sf_mask, set);

	if (err)
		goto give_sigsegv;

	/*
	 * Arguments to signal handler:
	 *
	 *   a0 = signal number
	 *   a1 = 0 (should be cause)
	 *   a2 = pointer to struct sigcontext
	 *
	 * $25 and c0_epc point to the signal handler, $29 points to the
	 * struct sigframe.
	 */
	regs->regs[ 4] = signr;
	regs->regs[ 5] = 0;
	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
	regs->regs[29] = (unsigned long) frame;
	regs->regs[31] = (unsigned long) frame->sf_code;
	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
	       current->comm, current->pid,
	       frame, regs->cp0_epc, regs->regs[31]);

	return 0;

give_sigsegv:
	force_sigsegv(signr, current);
	return -EFAULT;
}

static int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
	int signr, sigset_t *set, siginfo_t *info)
{
	struct rt_sigframe32 __user *frame;
	int err = 0;
	s32 sp;

	frame = get_sigframe(ka, regs, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
		goto give_sigsegv;

	err |= install_sigtramp(frame->rs_code, __NR_O32_rt_sigreturn);

	/* Convert (siginfo_t -> compat_siginfo_t) and copy to user. */
	err |= copy_siginfo_to_user32(&frame->rs_info, info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->rs_uc.uc_flags);
	err |= __put_user(0, &frame->rs_uc.uc_link);
	sp = (int) (long) current->sas_ss_sp;
	err |= __put_user(sp,
	                  &frame->rs_uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->regs[29]),
	                  &frame->rs_uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size,
	                  &frame->rs_uc.uc_stack.ss_size);
	err |= setup_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
	err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);

	if (err)
		goto give_sigsegv;

	/*
	 * Arguments to signal handler:
	 *
	 *   a0 = signal number
	 *   a1 = 0 (should be cause)
	 *   a2 = pointer to ucontext
	 *
	 * $25 and c0_epc point to the signal handler, $29 points to
	 * the struct rt_sigframe32.
	 */
	regs->regs[ 4] = signr;
	regs->regs[ 5] = (unsigned long) &frame->rs_info;
	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
	regs->regs[29] = (unsigned long) frame;
	regs->regs[31] = (unsigned long) frame->rs_code;
	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
	       current->comm, current->pid,
	       frame, regs->cp0_epc, regs->regs[31]);

	return 0;

give_sigsegv:
	force_sigsegv(signr, current);
	return -EFAULT;
}

/*
 * o32 compatibility on 64-bit kernels, without DSP ASE
 */
struct mips_abi mips_abi_32 = {
	.setup_frame	= setup_frame_32,
	.setup_rt_frame	= setup_rt_frame_32,
	.restart	= __NR_O32_restart_syscall
};

asmlinkage int sys32_rt_sigaction(int sig, const struct sigaction32 __user *act,
				  struct sigaction32 __user *oact,
				  unsigned int sigsetsize)
{
	struct k_sigaction new_sa, old_sa;
	int ret = -EINVAL;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		goto out;

	if (act) {
		s32 handler;
		int err = 0;

		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
			return -EFAULT;
		err |= __get_user(handler, &act->sa_handler);
		new_sa.sa.sa_handler = (void __user *)(s64)handler;
		err |= __get_user(new_sa.sa.sa_flags, &act->sa_flags);
		err |= get_sigset(&new_sa.sa.sa_mask, &act->sa_mask);
		if (err)
			return -EFAULT;
	}

	ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);

	if (!ret && oact) {
		int err = 0;

		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
			return -EFAULT;

		err |= __put_user((u32)(u64)old_sa.sa.sa_handler,
		                   &oact->sa_handler);
		err |= __put_user(old_sa.sa.sa_flags, &oact->sa_flags);
		err |= put_sigset(&old_sa.sa.sa_mask, &oact->sa_mask);
		if (err)
			return -EFAULT;
	}
out:
	return ret;
}

asmlinkage int sys32_rt_sigprocmask(int how, compat_sigset_t __user *set,
	compat_sigset_t __user *oset, unsigned int sigsetsize)
{
	sigset_t old_set, new_set;
	int ret;
	mm_segment_t old_fs = get_fs();

	if (set && get_sigset(&new_set, set))
		return -EFAULT;

	set_fs(KERNEL_DS);
	ret = sys_rt_sigprocmask(how, set ? (sigset_t __user *)&new_set : NULL,
				 oset ? (sigset_t __user *)&old_set : NULL,
				 sigsetsize);
	set_fs(old_fs);

	if (!ret && oset && put_sigset(&old_set, oset))
		return -EFAULT;

	return ret;
}

asmlinkage int sys32_rt_sigpending(compat_sigset_t __user *uset,
	unsigned int sigsetsize)
{
	int ret;
	sigset_t set;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	ret = sys_rt_sigpending((sigset_t __user *)&set, sigsetsize);
	set_fs(old_fs);

	if (!ret && put_sigset(&set, uset))
		return -EFAULT;

	return ret;
}

asmlinkage int sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo)
{
	siginfo_t info;
	int ret;
	mm_segment_t old_fs = get_fs();

	if (copy_from_user(&info, uinfo, 3*sizeof(int)) ||
	    copy_from_user(info._sifields._pad, uinfo->_sifields._pad, SI_PAD_SIZE))
		return -EFAULT;
	set_fs(KERNEL_DS);
	ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __user *)&info);
	set_fs(old_fs);
	return ret;
}

asmlinkage long
sys32_waitid(int which, compat_pid_t pid,
	     compat_siginfo_t __user *uinfo, int options,
	     struct compat_rusage __user *uru)
{
	siginfo_t info;
	struct rusage ru;
	long ret;
	mm_segment_t old_fs = get_fs();

	info.si_signo = 0;
	set_fs(KERNEL_DS);
	ret = sys_waitid(which, pid, (siginfo_t __user *) &info, options,
			 uru ? (struct rusage __user *) &ru : NULL);
	set_fs(old_fs);

	if (ret < 0 || info.si_signo == 0)
		return ret;

	if (uru && (ret = put_compat_rusage(&ru, uru)))
		return ret;

	BUG_ON(info.si_code & __SI_MASK);
	info.si_code |= __SI_CHLD;
	return copy_siginfo_to_user32(uinfo, &info);
}