ia32_signal.c

linux 内核源代码

	struct pt_regs tregs;

	frame = (struct rt_sigframe __user *)(regs->rsp - 4);

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

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	
	if (ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
		goto badframe;

	tregs = *regs;
	if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
		goto badframe;

	return eax;

badframe:
	signal_fault(regs,frame,"32bit rt sigreturn");
	return 0;
}	

/*
 * Set up a signal frame.
 */

static int
ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc, struct _fpstate_ia32 __user *fpstate,
		 struct pt_regs *regs, unsigned int mask)
{
	int tmp, err = 0;

	tmp = 0;
	__asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp));
	err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
	__asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp));
	err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
	__asm__("movl %%ds,%0" : "=r"(tmp): "0"(tmp));
	err |= __put_user(tmp, (unsigned int __user *)&sc->ds);
	__asm__("movl %%es,%0" : "=r"(tmp): "0"(tmp));
	err |= __put_user(tmp, (unsigned int __user *)&sc->es);

	err |= __put_user((u32)regs->rdi, &sc->edi);
	err |= __put_user((u32)regs->rsi, &sc->esi);
	err |= __put_user((u32)regs->rbp, &sc->ebp);
	err |= __put_user((u32)regs->rsp, &sc->esp);
	err |= __put_user((u32)regs->rbx, &sc->ebx);
	err |= __put_user((u32)regs->rdx, &sc->edx);
	err |= __put_user((u32)regs->rcx, &sc->ecx);
	err |= __put_user((u32)regs->rax, &sc->eax);
	err |= __put_user((u32)regs->cs, &sc->cs);
	err |= __put_user((u32)regs->ss, &sc->ss);
	err |= __put_user(current->thread.trap_no, &sc->trapno);
	err |= __put_user(current->thread.error_code, &sc->err);
	err |= __put_user((u32)regs->rip, &sc->eip);
	err |= __put_user((u32)regs->eflags, &sc->eflags);
	err |= __put_user((u32)regs->rsp, &sc->esp_at_signal);

	tmp = save_i387_ia32(current, fpstate, regs, 0);
	if (tmp < 0)
		err = -EFAULT;
	else { 
		clear_used_math();
		stts();
		err |= __put_user(ptr_to_compat(tmp ? fpstate : NULL),
					&sc->fpstate);
	}

	/* non-iBCS2 extensions.. */
	err |= __put_user(mask, &sc->oldmask);
	err |= __put_user(current->thread.cr2, &sc->cr2);

	return err;
}

/*
 * Determine which stack to use..
 */
static void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
{
	unsigned long rsp;

	/* Default to using normal stack */
	rsp = regs->rsp;

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (sas_ss_flags(rsp) == 0)
			rsp = current->sas_ss_sp + current->sas_ss_size;
	}

	/* This is the legacy signal stack switching. */
	else if ((regs->ss & 0xffff) != __USER_DS &&
		!(ka->sa.sa_flags & SA_RESTORER) &&
		 ka->sa.sa_restorer) {
		rsp = (unsigned long) ka->sa.sa_restorer;
	}

	rsp -= frame_size;
	/* Align the stack pointer according to the i386 ABI,
	 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
	rsp = ((rsp + 4) & -16ul) - 4;
	return (void __user *) rsp;
}

int ia32_setup_frame(int sig, struct k_sigaction *ka,
		     compat_sigset_t *set, struct pt_regs * regs)
{
	struct sigframe __user *frame;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	err |= __put_user(sig, &frame->sig);
	if (err)
		goto give_sigsegv;

	err |= ia32_setup_sigcontext(&frame->sc, &frame->fpstate, regs,
					set->sig[0]);
	if (err)
		goto give_sigsegv;

	if (_COMPAT_NSIG_WORDS > 1) {
		err |= __copy_to_user(frame->extramask, &set->sig[1],
				      sizeof(frame->extramask));
	}
	if (err)
		goto give_sigsegv;

	/* Return stub is in 32bit vsyscall page */
	{ 
		void __user *restorer;
		if (current->binfmt->hasvdso)
			restorer = VSYSCALL32_SIGRETURN;
		else
			restorer = (void *)&frame->retcode;
		if (ka->sa.sa_flags & SA_RESTORER)
			restorer = ka->sa.sa_restorer;       
		err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
	}
	/* These are actually not used anymore, but left because some 
	   gdb versions depend on them as a marker. */
	{ 
		/* copy_to_user optimizes that into a single 8 byte store */
		static const struct { 
			u16 poplmovl;
			u32 val;
			u16 int80;    
			u16 pad; 
		} __attribute__((packed)) code = { 
			0xb858,		 /* popl %eax ; movl $...,%eax */
			__NR_ia32_sigreturn,   
			0x80cd,		/* int $0x80 */
			0,
		}; 
		err |= __copy_to_user(frame->retcode, &code, 8); 
	}
	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->rsp = (unsigned long) frame;
	regs->rip = (unsigned long) ka->sa.sa_handler;

	/* Make -mregparm=3 work */
	regs->rax = sig;
	regs->rdx = 0;
	regs->rcx = 0;

	asm volatile("movl %0,%%ds" :: "r" (__USER32_DS)); 
	asm volatile("movl %0,%%es" :: "r" (__USER32_DS)); 

	regs->cs = __USER32_CS; 
	regs->ss = __USER32_DS; 

	set_fs(USER_DS);
	regs->eflags &= ~TF_MASK;
	if (test_thread_flag(TIF_SINGLESTEP))
		ptrace_notify(SIGTRAP);

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%u\n",
		current->comm, current->pid, frame, regs->rip, frame->pretcode);
#endif

	return 0;

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

int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			compat_sigset_t *set, struct pt_regs * regs)
{
	struct rt_sigframe __user *frame;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	{
		struct exec_domain *ed = current_thread_info()->exec_domain;
		err |= __put_user((ed
		    	   && ed->signal_invmap
		    	   && sig < 32
		    	   ? ed->signal_invmap[sig]
			   : sig),
			  &frame->sig);
	}
	err |= __put_user(ptr_to_compat(&frame->info), &frame->pinfo);
	err |= __put_user(ptr_to_compat(&frame->uc), &frame->puc);
	err |= copy_siginfo_to_user32(&frame->info, info);
	if (err)
		goto give_sigsegv;

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->rsp),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
			        regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto give_sigsegv;

	
	{ 
		void __user *restorer = VSYSCALL32_RTSIGRETURN; 
		if (ka->sa.sa_flags & SA_RESTORER)
			restorer = ka->sa.sa_restorer;       
		err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
	}

	/* This is movl $,%eax ; int $0x80 */
	/* Not actually used anymore, but left because some gdb versions
	   need it. */ 
	{ 
		/* __copy_to_user optimizes that into a single 8 byte store */
		static const struct { 
			u8 movl; 
			u32 val; 
			u16 int80; 
			u16 pad;
			u8  pad2;				
		} __attribute__((packed)) code = { 
			0xb8,
			__NR_ia32_rt_sigreturn,
			0x80cd,
			0,
		}; 
		err |= __copy_to_user(frame->retcode, &code, 8); 
	} 
	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->rsp = (unsigned long) frame;
	regs->rip = (unsigned long) ka->sa.sa_handler;

	/* Make -mregparm=3 work */
	regs->rax = sig;
	regs->rdx = (unsigned long) &frame->info;
	regs->rcx = (unsigned long) &frame->uc;

	/* Make -mregparm=3 work */
	regs->rax = sig;
	regs->rdx = (unsigned long) &frame->info;
	regs->rcx = (unsigned long) &frame->uc;

	asm volatile("movl %0,%%ds" :: "r" (__USER32_DS)); 
	asm volatile("movl %0,%%es" :: "r" (__USER32_DS)); 
	
	regs->cs = __USER32_CS; 
	regs->ss = __USER32_DS; 

	set_fs(USER_DS);
	regs->eflags &= ~TF_MASK;
	if (test_thread_flag(TIF_SINGLESTEP))
		ptrace_notify(SIGTRAP);

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%u\n",
		current->comm, current->pid, frame, regs->rip, frame->pretcode);
#endif

	return 0;

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