static ssize_t pdcs_auto_write()

in pdc_stable.c [742:803]

• 41 lines of code
• 9 McCabe index (conditional complexity)

static ssize_t pdcs_auto_write(struct kobject *kobj,
			       struct kobj_attribute *attr, const char *buf,
			       size_t count, int knob)
{
	struct pdcspath_entry *pathentry;
	unsigned char flags;
	char in[8], *temp;
	char c;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (!buf || !count)
		return -EINVAL;

	/* We'll use a local copy of buf */
	count = min_t(size_t, count, sizeof(in)-1);
	strncpy(in, buf, count);
	in[count] = '\0';

	/* Current flags are stored in primary boot path entry */
	pathentry = &pdcspath_entry_primary;
	
	/* Be nice to the existing flag record */
	read_lock(&pathentry->rw_lock);
	flags = pathentry->devpath.flags;
	read_unlock(&pathentry->rw_lock);
	
	DPRINTK("%s: flags before: 0x%X\n", __func__, flags);

	temp = skip_spaces(in);

	c = *temp++ - '0';
	if ((c != 0) && (c != 1))
		goto parse_error;
	if (c == 0)
		flags &= ~knob;
	else
		flags |= knob;
	
	DPRINTK("%s: flags after: 0x%X\n", __func__, flags);
		
	/* So far so good, let's get in deep */
	write_lock(&pathentry->rw_lock);
	
	/* Change the path entry flags first */
	pathentry->devpath.flags = flags;
		
	/* Now, dive in. Write back to the hardware */
	pdcspath_store(pathentry);
	write_unlock(&pathentry->rw_lock);
	
	printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" to \"%s\"\n",
		(knob & PF_AUTOBOOT) ? "autoboot" : "autosearch",
		(flags & knob) ? "On" : "Off");
	
	return count;

parse_error:
	printk(KERN_WARNING "%s: Parse error: expect \"n\" (n == 0 or 1)\n", __func__);
	return -EINVAL;
}