signal.c

优龙2410linux2.6.8内核源代码

		err |= __copy_to_user(&uc->sigmask, &setv,
				      2 * sizeof(unsigned int));

	/* Store registers */
	err |= __put_user(regs->pc, &((*gr)[SVR4_PC]));
	err |= __put_user(regs->npc, &((*gr)[SVR4_NPC]));
	err |= __put_user(regs->psr, &((*gr)[SVR4_PSR]));
	err |= __put_user(regs->y, &((*gr)[SVR4_Y]));
	
	/* Copy g[1..7] and o[0..7] registers */
	err |= __copy_to_user(&(*gr)[SVR4_G1], &regs->u_regs[UREG_G1],
			      sizeof(long) * 7);
	err |= __copy_to_user(&(*gr)[SVR4_O0], &regs->u_regs[UREG_I0],
			      sizeof(long) * 8);

	/* Setup sigaltstack */
	err |= __put_user(current->sas_ss_sp, &uc->stack.sp);
	err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &uc->stack.flags);
	err |= __put_user(current->sas_ss_size, &uc->stack.size);

	/* Save the currently window file: */

	/* 1. Link sfp->uc->gwins to our windows */
	err |= __put_user(gw, &mc->gwin);
	    
	/* 2. Number of windows to restore at setcontext(): */
	err |= __put_user(tp->w_saved, &gw->count);

	/* 3. Save each valid window
	 *    Currently, it makes a copy of the windows from the kernel copy.
	 *    David's code for SunOS, makes the copy but keeps the pointer to
	 *    the kernel.  My version makes the pointer point to a userland 
	 *    copy of those.  Mhm, I wonder if I shouldn't just ignore those
	 *    on setcontext and use those that are on the kernel, the signal
	 *    handler should not be modyfing those, mhm.
	 *
	 *    These windows are just used in case synchronize_user_stack failed
	 *    to flush the user windows.
	 */
	for (window = 0; window < tp->w_saved; window++) {
		err |= __put_user((int *) &(gw->win[window]), &gw->winptr[window]);
		err |= __copy_to_user(&gw->win[window],
				      &tp->reg_window[window],
				      sizeof(svr4_rwindow_t));
		err |= __put_user(0, gw->winptr[window]);
	}

	/* 4. We just pay attention to the gw->count field on setcontext */
	tp->w_saved = 0; /* So process is allowed to execute. */

	/* Setup the signal information.  Solaris expects a bunch of
	 * information to be passed to the signal handler, we don't provide
	 * that much currently, should use siginfo.
	 */
	err |= __put_user(signr, &si->siginfo.signo);
	err |= __put_user(SVR4_SINOINFO, &si->siginfo.code);
	if (err)
		goto sigsegv;

	regs->u_regs[UREG_FP] = (unsigned long) sfp;
	regs->pc = (unsigned long) sa->sa_handler;
	regs->npc = (regs->pc + 4);

	/* Arguments passed to signal handler */
	if (regs->u_regs[14]){
		struct reg_window __user *rw = (struct reg_window __user *)
			regs->u_regs[14];

		err |= __put_user(signr, &rw->ins[0]);
		err |= __put_user(si, &rw->ins[1]);
		err |= __put_user(uc, &rw->ins[2]);
		err |= __put_user(sfp, &rw->ins[6]);	/* frame pointer */
		if (err)
			goto sigsegv;

		regs->u_regs[UREG_I0] = signr;
		regs->u_regs[UREG_I1] = (unsigned long) si;
		regs->u_regs[UREG_I2] = (unsigned long) uc;
	}
	return;

sigill_and_return:
	do_exit(SIGILL);
sigsegv:
	do_exit(SIGSEGV);
}

asmlinkage int svr4_getcontext(svr4_ucontext_t __user *uc, struct pt_regs *regs)
{
	svr4_gregset_t  __user *gr;
	svr4_mcontext_t __user *mc;
	svr4_sigset_t	setv;
	int err = 0;

	synchronize_user_stack();

	if (current_thread_info()->w_saved)
		goto sigsegv_and_return;

	err = clear_user(uc, sizeof(*uc));
	if (err)
		return -EFAULT;

	/* Setup convenience variables */
	mc = &uc->mcontext;
	gr = &mc->greg;

	setv.sigbits[0] = current->blocked.sig[0];
	setv.sigbits[1] = current->blocked.sig[1];
	if (_NSIG_WORDS >= 4) {
		setv.sigbits[2] = current->blocked.sig[2];
		setv.sigbits[3] = current->blocked.sig[3];
		err |= __copy_to_user(&uc->sigmask, &setv, sizeof(svr4_sigset_t));
	} else
		err |= __copy_to_user(&uc->sigmask, &setv,
				      2 * sizeof(unsigned int));

	/* Store registers */
	err |= __put_user(regs->pc, &uc->mcontext.greg[SVR4_PC]);
	err |= __put_user(regs->npc, &uc->mcontext.greg[SVR4_NPC]);
	err |= __put_user(regs->psr, &uc->mcontext.greg[SVR4_PSR]);
	err |= __put_user(regs->y, &uc->mcontext.greg[SVR4_Y]);
	
	/* Copy g[1..7] and o[0..7] registers */
	err |= __copy_to_user(&(*gr)[SVR4_G1], &regs->u_regs[UREG_G1],
			      sizeof(uint) * 7);
	err |= __copy_to_user(&(*gr)[SVR4_O0], &regs->u_regs[UREG_I0],
			      sizeof(uint) * 8);

	/* Setup sigaltstack */
	err |= __put_user(current->sas_ss_sp, &uc->stack.sp);
	err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &uc->stack.flags);
	err |= __put_user(current->sas_ss_size, &uc->stack.size);

	/* The register file is not saved
	 * we have already stuffed all of it with sync_user_stack
	 */
	return (err ? -EFAULT : 0);

sigsegv_and_return:
	do_exit(SIGSEGV);
}

/* Set the context for a svr4 application, this is Solaris way to sigreturn */
asmlinkage int svr4_setcontext(svr4_ucontext_t __user *c, struct pt_regs *regs)
{
	svr4_gregset_t  __user *gr;
	unsigned long pc, npc, psr;
	mm_segment_t old_fs;
	sigset_t set;
	svr4_sigset_t setv;
	int err;
	stack_t st;
	
	/* Fixme: restore windows, or is this already taken care of in
	 * svr4_setup_frame when sync_user_windows is done?
	 */
	flush_user_windows();

	if (current_thread_info()->w_saved)
		goto sigsegv_and_return;

	if (((unsigned long) c) & 3)
		goto sigsegv_and_return;

	if (!__access_ok((unsigned long)c, sizeof(*c)))
		goto sigsegv_and_return;

	/* Check for valid PC and nPC */
	gr = &c->mcontext.greg;
	err = __get_user(pc, &((*gr)[SVR4_PC]));
	err |= __get_user(npc, &((*gr)[SVR4_NPC]));

	if ((pc | npc) & 3)
		goto sigsegv_and_return;

	/* Retrieve information from passed ucontext */
	/* note that nPC is ored a 1, this is used to inform entry.S */
	/* that we don't want it to mess with our PC and nPC */

	/* This is pretty much atomic, no amount locking would prevent
	 * the races which exist anyways.
	 */
	err |= __copy_from_user(&setv, &c->sigmask, sizeof(svr4_sigset_t));
	
	err |= __get_user(st.ss_sp, &c->stack.sp);
	err |= __get_user(st.ss_flags, &c->stack.flags);
	err |= __get_user(st.ss_size, &c->stack.size);
	
	if (err)
		goto sigsegv_and_return;
		
	/* 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((const stack_t __user *) &st, NULL,
		       regs->u_regs[UREG_I6]);
	set_fs(old_fs);
	
	set.sig[0] = setv.sigbits[0];
	set.sig[1] = setv.sigbits[1];
	if (_NSIG_WORDS >= 4) {
		set.sig[2] = setv.sigbits[2];
		set.sig[3] = setv.sigbits[3];
	}
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	regs->pc = pc;
	regs->npc = npc | 1;
	err |= __get_user(regs->y, &((*gr)[SVR4_Y]));
	err |= __get_user(psr, &((*gr)[SVR4_PSR]));
	regs->psr &= ~(PSR_ICC);
	regs->psr |= (psr & PSR_ICC);

	/* Restore g[1..7] and o[0..7] registers */
	err |= __copy_from_user(&regs->u_regs[UREG_G1], &(*gr)[SVR4_G1],
			      sizeof(long) * 7);
	err |= __copy_from_user(&regs->u_regs[UREG_I0], &(*gr)[SVR4_O0],
			      sizeof(long) * 8);
	return (err ? -EFAULT : 0);

sigsegv_and_return:
	do_exit(SIGSEGV);
}

static inline void
handle_signal(unsigned long signr, struct k_sigaction *ka,
	      siginfo_t *info, sigset_t *oldset, struct pt_regs *regs,
	      int svr4_signal)
{
	if (svr4_signal)
		setup_svr4_frame(&ka->sa, regs->pc, regs->npc, regs, signr, oldset);
	else {
		if (ka->sa.sa_flags & SA_SIGINFO)
			new_setup_rt_frame(ka, regs, signr, oldset, info);
		else if (current->thread.new_signal)
			new_setup_frame(ka, regs, signr, oldset);
		else
			setup_frame(&ka->sa, regs, signr, oldset, info);
	}
	if (ka->sa.sa_flags & SA_ONESHOT)
		ka->sa.sa_handler = SIG_DFL;
	if (!(ka->sa.sa_flags & SA_NOMASK)) {
		spin_lock_irq(&current->sighand->siglock);
		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
		sigaddset(&current->blocked, signr);
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
	}
}

static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
				   struct sigaction *sa)
{
	switch(regs->u_regs[UREG_I0]) {
	case ERESTART_RESTARTBLOCK:
	case ERESTARTNOHAND:
	no_system_call_restart:
		regs->u_regs[UREG_I0] = EINTR;
		regs->psr |= PSR_C;
		break;
	case ERESTARTSYS:
		if (!(sa->sa_flags & SA_RESTART))
			goto no_system_call_restart;
		/* fallthrough */
	case ERESTARTNOINTR:
		regs->u_regs[UREG_I0] = orig_i0;
		regs->pc -= 4;
		regs->npc -= 4;
	}
}

/* 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.
 */
asmlinkage int do_signal(sigset_t *oldset, struct pt_regs * regs,
			 unsigned long orig_i0, int restart_syscall)
{
	siginfo_t info;
	struct sparc_deliver_cookie cookie;
	int signr;

	/*
	 * XXX Disable svr4 signal handling until solaris emulation works.
	 * It is buggy - Anton
	 */
#define SVR4_SIGNAL_BROKEN 1
#ifdef SVR4_SIGNAL_BROKEN
	int svr4_signal = 0;
#else
	int svr4_signal = current->personality == PER_SVR4;
#endif

	cookie.restart_syscall = restart_syscall;
	cookie.orig_i0 = orig_i0;

	if (!oldset)
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, regs, &cookie);
	if (signr > 0) {
		struct k_sigaction *ka;
		
		ka = &current->sighand->action[signr-1];

		if (cookie.restart_syscall)
			syscall_restart(cookie.orig_i0, regs, &ka->sa);
		handle_signal(signr, ka, &info, oldset, regs, svr4_signal);
		return 1;
	}
	if (cookie.restart_syscall &&
	    (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
	     regs->u_regs[UREG_I0] == ERESTARTSYS ||
	     regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
		/* replay the system call when we are done */
		regs->u_regs[UREG_I0] = cookie.orig_i0;
		regs->pc -= 4;
		regs->npc -= 4;
	}
	if (cookie.restart_syscall &&
	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
		regs->u_regs[UREG_G1] = __NR_restart_syscall;
		regs->pc -= 4;
		regs->npc -= 4;
	}
	return 0;
}

asmlinkage int
do_sys_sigstack(struct sigstack __user *ssptr, struct sigstack __user *ossptr,
		unsigned long sp)
{
	int ret = -EFAULT;

	/* First see if old state is wanted. */
	if (ossptr) {
		if (put_user(current->sas_ss_sp + current->sas_ss_size,
			     &ossptr->the_stack) ||
		    __put_user(on_sig_stack(sp), &ossptr->cur_status))
			goto out;
	}

	/* Now see if we want to update the new state. */
	if (ssptr) {
		char *ss_sp;

		if (get_user(ss_sp, &ssptr->the_stack))
			goto out;
		/* If the current stack was set with sigaltstack, don't
		   swap stacks while we are on it.  */
		ret = -EPERM;
		if (current->sas_ss_sp && on_sig_stack(sp))
			goto out;

		/* Since we don't know the extent of the stack, and we don't
		   track onstack-ness, but rather calculate it, we must
		   presume a size.  Ho hum this interface is lossy.  */
		current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
		current->sas_ss_size = SIGSTKSZ;
	}
	ret = 0;
out:
	return ret;
}

void ptrace_signal_deliver(struct pt_regs *regs, void *cookie)
{
	struct sparc_deliver_cookie *cp = cookie;

	if (cp->restart_syscall &&
	    (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
	     regs->u_regs[UREG_I0] == ERESTARTSYS ||
	     regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
		/* replay the system call when we are done */
		regs->u_regs[UREG_I0] = cp->orig_i0;
		regs->pc -= 4;
		regs->npc -= 4;
		cp->restart_syscall = 0;
	}

	if (cp->restart_syscall &&
	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
		regs->u_regs[UREG_G1] = __NR_restart_syscall;
		regs->pc -= 4;
		regs->npc -= 4;
		cp->restart_syscall = 0;
	}
}