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

       /*
	* Creat system call.
	*/
creat(name, mode)
	char *name;
	int mode;
	{
	fast struct inode *ip;
	fast int fd;

	if ((ip = iname(name)) == NULL)
		{
		/*
		 * File does not exist. Mask the mode to
		 * ordinary type. Note that iname sets
		 * several globals for use by imkfile.
		 */
		if ((ip = imkfile(mode & 07777)) == NULL)
			return ERROR;
		}
	else
		{
		/*
		 * file exists
		 */
		if ((ip->mode & ITYPE) == IDIR)
			{
			u.error = EISDIR;
			irelse(ip);
			return ERROR;
			}
		if (!access(ip, IWRITE))
			{
			irelse(ip);
			return ERROR;
			}
		itrunc(ip); /* itrunc ignores special files */
		}
	fd = iopen(ip, IWRITE);
	irelse(ip);
	return (fd);
	}

       /*
	* Mknod system call
	*/
mknod(name, mode, dev)
	char *name;
	int  mode, dev;
	{
	fast struct inode *ip;

	if (!super())
		return;
	if ((ip = iname(name)) != NULL)
		{
		u.error = EEXIST;
		irelse(ip);
		return;
		}
	if ((ip = imkfile(mode, dev)) == NULL)
		return;
	irelse(ip);
	}

       /*
	* Make a new file on device u.iparent->dev and make an entry
	* in u.iparent. If it is an io file, set inode.addr[0] to dev.
	* A previous call to iname is required to set things up.
	*/
	struct inode *
imkfile(mode, dev)
	int mode, dev;
	{
	fast struct inode *ip;

	if (u.error != ENOENT)	 /* from iname() */
		return NULL;
	u.error = 0;
	if (!access(u.iparent, IWRITE))
		return NULL;
	ilock(u.iparent);
	ip = ialloc(u.iparent->dev);
	irelse(u.iparent);
	if (ip == NULL)
		return NULL;
	ilink(ip->inum);
	ip->nlinks = 1;
	ip->mode |= mode;
	ip->uid = u.uid;
	ip->gid = u.gid;
	if (mode & IIO)
		ip->addr[0] = dev;
	return (ip);
	}