signal32.c

来自「优龙2410linux2.6.8内核源代码」· C语言 代码 · 共 998 行 · 第 1/2 页

	siginfo_t info;

	if (copy_from_user(&s32, uthese, sizeof(compat_sigset_t)))
		return -EFAULT;
	sigset_from_compat(&s, &s32);
	if (uts && get_compat_timespec(&t, uts))
		return -EFAULT;
	set_fs(KERNEL_DS);
	/* The __user pointer casts are valid because of the set_fs() */
	ret = sys_rt_sigtimedwait((sigset_t __user *) &s,
			uinfo ? (siginfo_t __user *) &info : NULL,
			uts ? (struct timespec __user *) &t : NULL,
			sigsetsize);
	set_fs(old_fs);
	if (ret >= 0 && uinfo) {
		if (copy_siginfo_to_user32(uinfo, &info))
			return -EFAULT;
	}
	return ret;
}

/*
 * Note: it is necessary to treat pid and sig as unsigned ints, with the
 * corresponding cast to a signed int to insure that the proper conversion
 * (sign extension) between the register representation of a signed int
 * (msr in 32-bit mode) and the register representation of a signed int
 * (msr in 64-bit mode) is performed.
 */
long sys32_rt_sigqueueinfo(u32 pid, u32 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_SIZE32))
		return -EFAULT;
	set_fs (KERNEL_DS);
	/* The __user pointer cast is valid becasuse of the set_fs() */
	ret = sys_rt_sigqueueinfo((int)pid, (int)sig, (siginfo_t __user *) &info);
	set_fs (old_fs);
	return ret;
}

int sys32_rt_sigsuspend(compat_sigset_t __user * unewset, size_t sigsetsize, int p3,
		int p4, int p6, int p7, struct pt_regs *regs)
{
	sigset_t saveset, newset;
	compat_sigset_t s32;

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

	if (copy_from_user(&s32, unewset, sizeof(s32)))
		return -EFAULT;

	/*
	 * Swap the 2 words of the 64-bit sigset_t (they are stored
	 * in the "wrong" endian in 32-bit user storage).
	 */
	sigset_from_compat(&newset, &s32);

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

	regs->result = -EINTR;
	regs->gpr[3] = EINTR;
	regs->ccr |= 0x10000000;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal32(&saveset, regs))
			/*
			 * If a signal handler needs to be called,
			 * do_signal32() has set R3 to the signal number (the
			 * first argument of the signal handler), so don't
			 * overwrite that with EINTR !
			 * In the other cases, do_signal32() doesn't touch 
			 * R3, so it's still set to -EINTR (see above).
			 */
			return regs->gpr[3];
	}
}

/*
 *  Start Alternate signal stack support
 *
 *  System Calls
 *       sigaltatck               sys32_sigaltstack
 */

int sys32_sigaltstack(u32 __new, u32 __old, int r5,
		      int r6, int r7, int r8, struct pt_regs *regs)
{
	stack_32_t __user * newstack = (stack_32_t __user *)(long) __new;
	stack_32_t __user * oldstack = (stack_32_t __user *)(long) __old;
	stack_t uss, uoss;
	int ret;
	mm_segment_t old_fs;
	unsigned long sp;
	compat_uptr_t ss_sp;

	/*
	 * set sp to the user stack on entry to the system call
	 * the system call router sets R9 to the saved registers
	 */
	sp = regs->gpr[1];

	/* Put new stack info in local 64 bit stack struct */
	if (newstack) {
		if (get_user(ss_sp, &newstack->ss_sp) ||
		    __get_user(uss.ss_flags, &newstack->ss_flags) ||
		    __get_user(uss.ss_size, &newstack->ss_size))
			return -EFAULT;
		uss.ss_sp = compat_ptr(ss_sp);
	}

	old_fs = get_fs();
	set_fs(KERNEL_DS);
	/* The __user pointer casts are valid because of the set_fs() */
	ret = do_sigaltstack(
		newstack ? (stack_t __user *) &uss : NULL,
		oldstack ? (stack_t __user *) &uoss : NULL,
		sp);
	set_fs(old_fs);
	/* Copy the stack information to the user output buffer */
	if (!ret && oldstack  &&
		(put_user((long)uoss.ss_sp, &oldstack->ss_sp) ||
		 __put_user(uoss.ss_flags, &oldstack->ss_flags) ||
		 __put_user(uoss.ss_size, &oldstack->ss_size)))
		return -EFAULT;
	return ret;
}


/*
 * Set up a signal frame for a "real-time" signal handler
 * (one which gets siginfo).
 */
static void handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
			       siginfo_t *info, sigset_t *oldset,
			       struct pt_regs * regs, unsigned long newsp)
{
	struct rt_sigframe32 __user *rt_sf;
	struct mcontext32 __user *frame;
	unsigned long origsp = newsp;
	compat_sigset_t c_oldset;

	/* Set up Signal Frame */
	/* Put a Real Time Context onto stack */
	newsp -= sizeof(*rt_sf);
	rt_sf = (struct rt_sigframe32 __user *)newsp;

	/* create a stack frame for the caller of the handler */
	newsp -= __SIGNAL_FRAMESIZE32 + 16;

	if (verify_area(VERIFY_WRITE, (void __user *)newsp, origsp - newsp))
		goto badframe;

	compat_from_sigset(&c_oldset, oldset);

	/* Put the siginfo & fill in most of the ucontext */
	if (copy_siginfo_to_user32(&rt_sf->info, info)
	    || __put_user(0, &rt_sf->uc.uc_flags)
	    || __put_user(0, &rt_sf->uc.uc_link)
	    || __put_user(current->sas_ss_sp, &rt_sf->uc.uc_stack.ss_sp)
	    || __put_user(sas_ss_flags(regs->gpr[1]),
			  &rt_sf->uc.uc_stack.ss_flags)
	    || __put_user(current->sas_ss_size, &rt_sf->uc.uc_stack.ss_size)
	    || __put_user((u32)(u64)&rt_sf->uc.uc_mcontext, &rt_sf->uc.uc_regs)
	    || __copy_to_user(&rt_sf->uc.uc_sigmask, &c_oldset, sizeof(c_oldset)))
		goto badframe;

	/* Save user registers on the stack */
	frame = &rt_sf->uc.uc_mcontext;
	if (save_user_regs(regs, frame, __NR_rt_sigreturn))
		goto badframe;

	if (put_user(regs->gpr[1], (unsigned long __user *)newsp))
		goto badframe;
	regs->gpr[1] = (unsigned long) newsp;
	regs->gpr[3] = sig;
	regs->gpr[4] = (unsigned long) &rt_sf->info;
	regs->gpr[5] = (unsigned long) &rt_sf->uc;
	regs->gpr[6] = (unsigned long) rt_sf;
	regs->nip = (unsigned long) ka->sa.sa_handler;
	regs->link = (unsigned long) frame->tramp;
	regs->trap = 0;
	regs->result = 0;

	return;

badframe:
#if DEBUG_SIG
	printk("badframe in handle_rt_signal, regs=%p frame=%p newsp=%lx\n",
	       regs, frame, newsp);
#endif
	if (sig == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
}

static long do_setcontext32(struct ucontext32 __user *ucp, struct pt_regs *regs, int sig)
{
	compat_sigset_t c_set;
	sigset_t set;
	u32 mcp;

	if (__copy_from_user(&c_set, &ucp->uc_sigmask, sizeof(c_set))
	    || __get_user(mcp, &ucp->uc_regs))
		return -EFAULT;
	sigset_from_compat(&set, &c_set);
	restore_sigmask(&set);
	if (restore_user_regs(regs, (struct mcontext32 __user *)(u64)mcp, sig))
		return -EFAULT;

	return 0;
}

/*
 * Handle {get,set,swap}_context operations for 32 bits processes
 */

long sys32_swapcontext(struct ucontext32 __user *old_ctx,
		       struct ucontext32 __user *new_ctx,
		       int ctx_size, int r6, int r7, int r8, struct pt_regs *regs)
{
	unsigned char tmp;
	compat_sigset_t c_set;

	/* Context size is for future use. Right now, we only make sure
	 * we are passed something we understand
	 */
	if (ctx_size < sizeof(struct ucontext32))
		return -EINVAL;

	if (old_ctx != NULL) {
		compat_from_sigset(&c_set, &current->blocked);
		if (verify_area(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
		    || save_user_regs(regs, &old_ctx->uc_mcontext, 0)
		    || __copy_to_user(&old_ctx->uc_sigmask, &c_set, sizeof(c_set))
		    || __put_user((u32)(u64)&old_ctx->uc_mcontext, &old_ctx->uc_regs))
			return -EFAULT;
	}
	if (new_ctx == NULL)
		return 0;
	if (verify_area(VERIFY_READ, new_ctx, sizeof(*new_ctx))
	    || __get_user(tmp, (u8 __user *) new_ctx)
	    || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
		return -EFAULT;

	/*
	 * If we get a fault copying the context into the kernel's
	 * image of the user's registers, we can't just return -EFAULT
	 * because the user's registers will be corrupted.  For instance
	 * the NIP value may have been updated but not some of the
	 * other registers.  Given that we have done the verify_area
	 * and successfully read the first and last bytes of the region
	 * above, this should only happen in an out-of-memory situation
	 * or if another thread unmaps the region containing the context.
	 * We kill the task with a SIGSEGV in this situation.
	 */
	if (do_setcontext32(new_ctx, regs, 0))
		do_exit(SIGSEGV);

	return 0;
}

long sys32_rt_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
		     struct pt_regs *regs)
{
	struct rt_sigframe32 __user *rt_sf;
	int ret;


	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	rt_sf = (struct rt_sigframe32 __user *)
		(regs->gpr[1] + __SIGNAL_FRAMESIZE32 + 16);
	if (verify_area(VERIFY_READ, rt_sf, sizeof(*rt_sf)))
		goto bad;
	if (do_setcontext32(&rt_sf->uc, regs, 1))
		goto bad;

	/*
	 * It's not clear whether or why it is desirable to save the
	 * sigaltstack setting on signal delivery and restore it on
	 * signal return.  But other architectures do this and we have
	 * always done it up until now so it is probably better not to
	 * change it.  -- paulus
	 * We use the sys32_ version that does the 32/64 bits conversion
	 * and takes userland pointer directly. What about error checking ?
	 * nobody does any...
	 */
       	sys32_sigaltstack((u32)(u64)&rt_sf->uc.uc_stack, 0, 0, 0, 0, 0, regs);

	ret = regs->result;

	return ret;

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


/*
 * OK, we're invoking a handler
 */
static void handle_signal32(unsigned long sig, struct k_sigaction *ka,
			    siginfo_t *info, sigset_t *oldset,
			    struct pt_regs * regs, unsigned long newsp)
{
	struct sigcontext32 __user *sc;
	struct sigregs32 __user *frame;
	unsigned long origsp = newsp;

	/* Set up Signal Frame */
	newsp -= sizeof(struct sigregs32);
	frame = (struct sigregs32 __user *) newsp;

	/* Put a sigcontext on the stack */
	newsp -= sizeof(*sc);
	sc = (struct sigcontext32 __user *) newsp;

	/* create a stack frame for the caller of the handler */
	newsp -= __SIGNAL_FRAMESIZE32;

	if (verify_area(VERIFY_WRITE, (void __user *) newsp, origsp - newsp))
		goto badframe;

#if _NSIG != 64
#error "Please adjust handle_signal32()"
#endif
	if (__put_user((u32)(u64)ka->sa.sa_handler, &sc->handler)
	    || __put_user(oldset->sig[0], &sc->oldmask)
	    || __put_user((oldset->sig[0] >> 32), &sc->_unused[3])
	    || __put_user((u32)(u64)frame, &sc->regs)
	    || __put_user(sig, &sc->signal))
		goto badframe;

	if (save_user_regs(regs, &frame->mctx, __NR_sigreturn))
		goto badframe;

	if (put_user(regs->gpr[1], (unsigned long __user *)newsp))
		goto badframe;
	regs->gpr[1] = (unsigned long) newsp;
	regs->gpr[3] = sig;
	regs->gpr[4] = (unsigned long) sc;
	regs->nip = (unsigned long) ka->sa.sa_handler;
	regs->link = (unsigned long) frame->mctx.tramp;
	regs->trap = 0;
	regs->result = 0;

	return;

badframe:
#if DEBUG_SIG
	printk("badframe in handle_signal, regs=%p frame=%x newsp=%x\n",
	       regs, frame, *newspp);
#endif
	if (sig == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
}

/*
 * Do a signal return; undo the signal stack.
 */
long sys32_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
		       struct pt_regs *regs)
{
	struct sigcontext32 __user *sc;
	struct sigcontext32 sigctx;
	struct mcontext32 __user *sr;
	sigset_t set;
	int ret;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	sc = (struct sigcontext32 __user *)(regs->gpr[1] + __SIGNAL_FRAMESIZE32);
	if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
		goto badframe;

	/*
	 * Note that PPC32 puts the upper 32 bits of the sigmask in the
	 * unused part of the signal stackframe
	 */
	set.sig[0] = sigctx.oldmask + ((long)(sigctx._unused[3]) << 32);
	restore_sigmask(&set);

	sr = (struct mcontext32 __user *)(u64)sigctx.regs;
	if (verify_area(VERIFY_READ, sr, sizeof(*sr))
	    || restore_user_regs(regs, sr, 1))
		goto badframe;

	ret = regs->result;
	return ret;

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



/*
 *  Start of do_signal32 routine
 *
 *   This routine gets control when a pending signal needs to be processed
 *     in the 32 bit target thread -
 *
 *   It handles both rt and non-rt signals
 */

/*
 * 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.
 */

int do_signal32(sigset_t *oldset, struct pt_regs *regs)
{
	siginfo_t info;
	struct k_sigaction *ka;
	unsigned int frame, newsp;
	int signr, ret;

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

	newsp = frame = 0;

	signr = get_signal_to_deliver(&info, regs, NULL);

	ka = (signr == 0)? NULL: &current->sighand->action[signr-1];

	if (TRAP(regs) == 0x0C00		/* System Call! */
	    && regs->ccr & 0x10000000		/* error signalled */
	    && ((ret = regs->gpr[3]) == ERESTARTSYS
		|| ret == ERESTARTNOHAND || ret == ERESTARTNOINTR
		|| ret == ERESTART_RESTARTBLOCK)) {

		if (signr > 0
		    && (ret == ERESTARTNOHAND || ret == ERESTART_RESTARTBLOCK
			|| (ret == ERESTARTSYS
			    && !(ka->sa.sa_flags & SA_RESTART)))) {
			/* make the system call return an EINTR error */
			regs->result = -EINTR;
			regs->gpr[3] = EINTR;
			/* note that the cr0.SO bit is already set */
		} else {
			regs->nip -= 4;	/* Back up & retry system call */
			regs->result = 0;
			regs->trap = 0;
			if (ret == ERESTART_RESTARTBLOCK)
				regs->gpr[0] = __NR_restart_syscall;
			else
				regs->gpr[3] = regs->orig_gpr3;
		}
	}

	if (signr == 0)
		return 0;		/* no signals delivered */

	if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size
	    && (!on_sig_stack(regs->gpr[1])))
		newsp = (current->sas_ss_sp + current->sas_ss_size);
	else
		newsp = regs->gpr[1];
	newsp &= ~0xfUL;

	/* Whee!  Actually deliver the signal.  */
	if (ka->sa.sa_flags & SA_SIGINFO)
		handle_rt_signal32(signr, ka, &info, oldset, regs, newsp);
	else
		handle_signal32(signr, ka, &info, oldset, regs, newsp);

	if (ka->sa.sa_flags & SA_ONESHOT)
		ka->sa.sa_handler = SIG_DFL;

	if (!(ka->sa.sa_flags & SA_NODEFER)) {
		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);
	}

	return 1;
}