ptrace.c

linux-2.6.15.6

		if (addr == (addr_t) &dummy32->regs.psw.mask) {
			/* Fake a 31 bit psw mask. */
			tmp = (__u32)(__KSTK_PTREGS(child)->psw.mask >> 32);
			tmp = PSW32_MASK_MERGE(PSW32_USER_BITS, tmp);
		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
			/* Fake a 31 bit psw address. */
			tmp = (__u32) __KSTK_PTREGS(child)->psw.addr |
				PSW32_ADDR_AMODE31;
		} else {
			/* gpr 0-15 */
			tmp = *(__u32 *)((addr_t) &__KSTK_PTREGS(child)->psw +
					 addr*2 + 4);
		}
	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.acrs;
		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);

	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		tmp = *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4);

	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are stored in the thread structure 
		 */
	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
		tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);

	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
		/*
		 * per_info is found in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.per_info;
		/* This is magic. See per_struct and per_struct32. */
		if ((offset >= (addr_t) &dummy_per32->control_regs &&
		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
		    (offset >= (addr_t) &dummy_per32->starting_addr &&
		     offset <= (addr_t) &dummy_per32->ending_addr) ||
		    offset == (addr_t) &dummy_per32->lowcore.words.address)
			offset = offset*2 + 4;
		else
			offset = offset*2;
		tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);

	} else
		tmp = 0;

	return put_user(tmp, (__u32 __user *) data);
}

/*
 * Same as poke_user but for a 31 bit program.
 */
static int
poke_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
{
	struct user32 *dummy32 = NULL;
	per_struct32 *dummy_per32 = NULL;
	addr_t offset;
	__u32 tmp;

	if (!test_thread_flag(TIF_31BIT) ||
	    (addr & 3) || addr > sizeof(struct user32) - 3)
		return -EIO;

	tmp = (__u32) data;

	if (addr < (addr_t) &dummy32->regs.acrs) {
		/*
		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
		 */
		if (addr == (addr_t) &dummy32->regs.psw.mask) {
			/* Build a 64 bit psw mask from 31 bit mask. */
			if (tmp != PSW32_MASK_MERGE(PSW32_USER_BITS, tmp))
				/* Invalid psw mask. */
				return -EINVAL;
			__KSTK_PTREGS(child)->psw.mask =
				PSW_MASK_MERGE(PSW_USER32_BITS, (__u64) tmp << 32);
		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
			/* Build a 64 bit psw address from 31 bit address. */
			__KSTK_PTREGS(child)->psw.addr = 
				(__u64) tmp & PSW32_ADDR_INSN;
		} else {
			/* gpr 0-15 */
			*(__u32*)((addr_t) &__KSTK_PTREGS(child)->psw
				  + addr*2 + 4) = tmp;
		}
	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.acrs;
		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;

	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		*(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4) = tmp;

	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are stored in the thread structure 
		 */
		if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
		    (tmp & ~FPC_VALID_MASK) != 0)
			/* Invalid floating point control. */
			return -EINVAL;
	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
		*(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;

	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
		/*
		 * per_info is found in the thread structure.
		 */
		offset = addr - (addr_t) &dummy32->regs.per_info;
		/*
		 * This is magic. See per_struct and per_struct32.
		 * By incident the offsets in per_struct are exactly
		 * twice the offsets in per_struct32 for all fields.
		 * The 8 byte fields need special handling though,
		 * because the second half (bytes 4-7) is needed and
		 * not the first half.
		 */
		if ((offset >= (addr_t) &dummy_per32->control_regs &&
		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
		    (offset >= (addr_t) &dummy_per32->starting_addr &&
		     offset <= (addr_t) &dummy_per32->ending_addr) ||
		    offset == (addr_t) &dummy_per32->lowcore.words.address)
			offset = offset*2 + 4;
		else
			offset = offset*2;
		*(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;

	}

	FixPerRegisters(child);
	return 0;
}

static int
do_ptrace_emu31(struct task_struct *child, long request, long addr, long data)
{
	unsigned int tmp;  /* 4 bytes !! */
	ptrace_area_emu31 parea; 
	int copied, ret;

	switch (request) {
	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
		/* read word at location addr. */
		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
		if (copied != sizeof(tmp))
			return -EIO;
		return put_user(tmp, (unsigned int __user *) data);

	case PTRACE_PEEKUSR:
		/* read the word at location addr in the USER area. */
		return peek_user_emu31(child, addr, data);

	case PTRACE_POKETEXT:
	case PTRACE_POKEDATA:
		/* write the word at location addr. */
		tmp = data;
		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1);
		if (copied != sizeof(tmp))
			return -EIO;
		return 0;

	case PTRACE_POKEUSR:
		/* write the word at location addr in the USER area */
		return poke_user_emu31(child, addr, data);

	case PTRACE_PEEKUSR_AREA:
	case PTRACE_POKEUSR_AREA:
		if (copy_from_user(&parea, (void __user *) addr,
							sizeof(parea)))
			return -EFAULT;
		addr = parea.kernel_addr;
		data = parea.process_addr;
		copied = 0;
		while (copied < parea.len) {
			if (request == PTRACE_PEEKUSR_AREA)
				ret = peek_user_emu31(child, addr, data);
			else {
				__u32 tmp;
				if (get_user (tmp, (__u32 __user *) data))
					return -EFAULT;
				ret = poke_user_emu31(child, addr, tmp);
			}
			if (ret)
				return ret;
			addr += sizeof(unsigned int);
			data += sizeof(unsigned int);
			copied += sizeof(unsigned int);
		}
		return 0;
	case PTRACE_GETEVENTMSG:
		return put_user((__u32) child->ptrace_message,
				(unsigned int __user *) data);
	case PTRACE_GETSIGINFO:
		if (child->last_siginfo == NULL)
			return -EINVAL;
		return copy_siginfo_to_user32((compat_siginfo_t __user *) data,
					      child->last_siginfo);
	case PTRACE_SETSIGINFO:
		if (child->last_siginfo == NULL)
			return -EINVAL;
		return copy_siginfo_from_user32(child->last_siginfo,
						(compat_siginfo_t __user *) data);
	}
	return ptrace_request(child, request, addr, data);
}
#endif

#define PT32_IEEE_IP 0x13c

static int
do_ptrace(struct task_struct *child, long request, long addr, long data)
{
	int ret;

	if (request == PTRACE_ATTACH)
		return ptrace_attach(child);

	/*
	 * Special cases to get/store the ieee instructions pointer.
	 */
	if (child == current) {
		if (request == PTRACE_PEEKUSR && addr == PT_IEEE_IP)
			return peek_user(child, addr, data);
		if (request == PTRACE_POKEUSR && addr == PT_IEEE_IP)
			return poke_user(child, addr, data);
#ifdef CONFIG_S390_SUPPORT
		if (request == PTRACE_PEEKUSR &&
		    addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
			return peek_user_emu31(child, addr, data);
		if (request == PTRACE_POKEUSR &&
		    addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
			return poke_user_emu31(child, addr, data);
#endif
	}

	ret = ptrace_check_attach(child, request == PTRACE_KILL);
	if (ret < 0)
		return ret;

	switch (request) {
	case PTRACE_SYSCALL:
		/* continue and stop at next (return from) syscall */
	case PTRACE_CONT:
		/* restart after signal. */
		if (!valid_signal(data))
			return -EIO;
		if (request == PTRACE_SYSCALL)
			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		else
			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->exit_code = data;
		/* make sure the single step bit is not set. */
		clear_single_step(child);
		wake_up_process(child);
		return 0;

	case PTRACE_KILL:
		/*
		 * make the child exit.  Best I can do is send it a sigkill. 
		 * perhaps it should be put in the status that it wants to 
		 * exit.
		 */
		if (child->exit_state == EXIT_ZOMBIE) /* already dead */
			return 0;
		child->exit_code = SIGKILL;
		/* make sure the single step bit is not set. */
		clear_single_step(child);
		wake_up_process(child);
		return 0;

	case PTRACE_SINGLESTEP:
		/* set the trap flag. */
		if (!valid_signal(data))
			return -EIO;
		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->exit_code = data;
		if (data)
			set_tsk_thread_flag(child, TIF_SINGLE_STEP);
		else
			set_single_step(child);
		/* give it a chance to run. */
		wake_up_process(child);
		return 0;

	case PTRACE_DETACH:
		/* detach a process that was attached. */
		return ptrace_detach(child, data);


	/* Do requests that differ for 31/64 bit */
	default:
#ifdef CONFIG_S390_SUPPORT
		if (test_thread_flag(TIF_31BIT))
			return do_ptrace_emu31(child, request, addr, data);
#endif
		return do_ptrace_normal(child, request, addr, data);
	}
	/* Not reached.  */
	return -EIO;
}

asmlinkage long
sys_ptrace(long request, long pid, long addr, long data)
{
	struct task_struct *child;
	int ret;

	lock_kernel();

	if (request == PTRACE_TRACEME) {
		/* are we already being traced? */
		ret = -EPERM;
		if (current->ptrace & PT_PTRACED)
			goto out;
		ret = security_ptrace(current->parent, current);
		if (ret)
			goto out;
		/* set the ptrace bit in the process flags. */
		current->ptrace |= PT_PTRACED;
		goto out;
	}

	ret = -EPERM;
	if (pid == 1)		/* you may not mess with init */
		goto out;

	ret = -ESRCH;
	read_lock(&tasklist_lock);
	child = find_task_by_pid(pid);
	if (child)
		get_task_struct(child);
	read_unlock(&tasklist_lock);
	if (!child)
		goto out;

	ret = do_ptrace(child, request, addr, data);

	put_task_struct(child);
out:
	unlock_kernel();
	return ret;
}

asmlinkage void
syscall_trace(struct pt_regs *regs, int entryexit)
{
	if (unlikely(current->audit_context) && entryexit)
		audit_syscall_exit(current, AUDITSC_RESULT(regs->gprs[2]), regs->gprs[2]);

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		goto out;
	if (!(current->ptrace & PT_PTRACED))
		goto out;
	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
				 ? 0x80 : 0));

	/*
	 * If the debuffer has set an invalid system call number,
	 * we prepare to skip the system call restart handling.
	 */
	if (!entryexit && regs->gprs[2] >= NR_syscalls)
		regs->trap = -1;

	/*
	 * this isn't the same as continuing with a signal, but it will do
	 * for normal use.  strace only continues with a signal if the
	 * stopping signal is not SIGTRAP.  -brl
	 */
	if (current->exit_code) {
		send_sig(current->exit_code, current, 1);
		current->exit_code = 0;
	}
 out:
	if (unlikely(current->audit_context) && !entryexit)
		audit_syscall_entry(current, 
				    test_thread_flag(TIF_31BIT)?AUDIT_ARCH_S390:AUDIT_ARCH_S390X,
				    regs->gprs[2], regs->orig_gpr2, regs->gprs[3],
				    regs->gprs[4], regs->gprs[5]);
}