#include "sys.h"
#include "buf.h"
#include "proc.h"
#include "inode.h"

extern struct inode *rootdir;

       /*
	* Turn a pathname into a locked inode.
	* Leaves u.offset and u.segflg ready
	* for a directory write.
	*/
	struct inode *
iname(name)
	char *name;
	{
	fast struct inode *ip, *parent;
	fast int inum;

	u.iparent = NULL;
	for (ip = u.cdir; getbyte(name) == '/'; name++)
		ip = rootdir;
	ilock(ip);
	for(;;)
		{
		if (getbyte(name) == 0)
			return (ip);
		if ((ip->mode & ITYPE) != IDIR)
			{
			u.error = ENOTDIR;
			break;
			}
		u.iparent = parent = ip;
		if (!access(ip, IEXEC))
			break;
		if ((inum = dlook(ip, &name)) == 0)
			break;
		parent->count++;
		irelse(parent);
		ip = iget(inum, parent->dev);
		parent->count--;
		if (ip == NULL)
			return NULL;
		}

	irelse(ip);	/* no sleeps between now and create */
	return NULL;
	}

       /*
	* Search the directory for the next name in the pathname.
	* Advance *np past the name and any /'s, and leave a 0
	* terminated copy of the name in u.dir.name. If found:
	* leave u.offset ready to overwrite the entry, leave
	* a copy of the entry in u.dirent, and return the inumber.
	* If not found: leave u.offset at a free slot or at the end,
	* and return 0.
	*/
dlook(ip, np)
	struct inode *ip;
	char **np;
	{
	fast UINT nblks, tail, log;
	static UINT phys, end, dummy;
	static char c, *p, *nambuf;
	static struct buf *b;
	static struct dir *d;
	struct dir *place;
	UINT slot;

	nambuf = u.dir.name;
	copyin(*np, nambuf, 14);
	for (p = nambuf, end = &nambuf[14]; p < end; p++)
		if (*p == 0 || *p == '/')
			{
			*p = 0;
			break;
			}
	p = *np + (p - nambuf);
	until ((c = getbyte(p)) == 0 || c == '/')
		p++;
	while (getbyte(p) == '/')
		p++;
	*np = p;

	nblks = (ip->size >> 9);	/* whole blocks */
	tail = ip->size & 511;
	if (tail)
		nblks++;
	slot = 0;
	place = 0;
	for (log = 0; log < nblks; log++)
		{
		if ((phys = imap(ip, log, &dummy)) == 0)
			continue;
		if ((b = bread(phys, ip->dev)) == 0)
			continue;
		end = b->data + ((tail && log == nblks-1)? tail : 512);
		for (d = b->data; d < end; d++, place++)
			{
			if (d->inum == 0)
				{
				if (slot == 0)
					slot = place;
				}
			else if (direqu(d->name, u.dir.name))
				{
				u.offset = place;
				brelse(b);
				return (d->inum);
				}
			}
		brelse(b);
		}
	/*
	 * Name not found.
	 */
	u.offset = (slot)? slot : place;
	if (!u.error)
		{
		if (getbyte(*np) == '\0')
			u.error = ENOENT;
		else
			u.error = ENOTDIR; /* for imkfile */
		}
	return (0);
	}

	/*
	 * Check equality of two directory entries
	 */
direqu(a, b)
	char *a, *b;
	{
	static char *x, *y;
	static int i;

	x = a;
	y = b;
	for (i = 0; i < 14; i++)
		{
		if (*x != *y)
			return NO;
		if (*x == 0)
			return YES;
		x++;
		y++;
		}
	return YES;
	}