long arch_ptrace()

in kernel/ptrace.c [161:272]

• 93 lines of code
• 36 McCabe index (conditional complexity)

long arch_ptrace(struct task_struct *child, long request,
		 unsigned long addr, unsigned long data)
{
	unsigned long tmp;
	int i, ret = 0;
	int regno = addr >> 2; /* temporary hack. */
	unsigned long __user *datap = (unsigned long __user *) data;

	switch (request) {
	/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR:
		if (addr & 3)
			goto out_eio;

		if (regno >= 0 && regno < 19) {
			tmp = get_reg(child, regno);
		} else if (regno >= 21 && regno < 49) {
			tmp = child->thread.fp[regno - 21];
			/* Convert internal fpu reg representation
			 * into long double format
			 */
			if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
				tmp = ((tmp & 0xffff0000) << 15) |
				      ((tmp & 0x0000ffff) << 16);
#ifndef CONFIG_MMU
		} else if (regno == 49) {
			tmp = child->mm->start_code;
		} else if (regno == 50) {
			tmp = child->mm->start_data;
		} else if (regno == 51) {
			tmp = child->mm->end_code;
#endif
		} else
			goto out_eio;
		ret = put_user(tmp, datap);
		break;

	case PTRACE_POKEUSR:
	/* write the word at location addr in the USER area */
		if (addr & 3)
			goto out_eio;

		if (regno == PT_SR) {
			data &= SR_MASK;
			data |= get_reg(child, PT_SR) & ~SR_MASK;
		}
		if (regno >= 0 && regno < 19) {
			if (put_reg(child, regno, data))
				goto out_eio;
		} else if (regno >= 21 && regno < 48) {
			/* Convert long double format
			 * into internal fpu reg representation
			 */
			if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
				data <<= 15;
				data = (data & 0xffff0000) |
				       ((data & 0x0000ffff) >> 1);
			}
			child->thread.fp[regno - 21] = data;
		} else
			goto out_eio;
		break;

	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
		for (i = 0; i < 19; i++) {
			tmp = get_reg(child, i);
			ret = put_user(tmp, datap);
			if (ret)
				break;
			datap++;
		}
		break;

	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
		for (i = 0; i < 19; i++) {
			ret = get_user(tmp, datap);
			if (ret)
				break;
			if (i == PT_SR) {
				tmp &= SR_MASK;
				tmp |= get_reg(child, PT_SR) & ~SR_MASK;
			}
			put_reg(child, i, tmp);
			datap++;
		}
		break;

	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
		if (copy_to_user(datap, &child->thread.fp,
				 sizeof(struct user_m68kfp_struct)))
			ret = -EFAULT;
		break;

	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
		if (copy_from_user(&child->thread.fp, datap,
				   sizeof(struct user_m68kfp_struct)))
			ret = -EFAULT;
		break;

	case PTRACE_GET_THREAD_AREA:
		ret = put_user(task_thread_info(child)->tp_value, datap);
		break;

	default:
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
out_eio:
	return -EIO;
}