Example #1
0
/*
 * Set various file attributes.
 * N.B. After this call fhp needs an fh_put
 */
__be32
nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
	     int check_guard, time_t guardtime)
{
	struct dentry	*dentry;
	struct inode	*inode;
	int		accmode = MAY_SATTR;
	int		ftype = 0;
	int		imode;
	__be32		err;
	int		host_err;
	int		size_change = 0;

	if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
		accmode |= MAY_WRITE|MAY_OWNER_OVERRIDE;
	if (iap->ia_valid & ATTR_SIZE)
		ftype = S_IFREG;

	/* Get inode */
	err = fh_verify(rqstp, fhp, ftype, accmode);
	if (err)
		goto out;

	dentry = fhp->fh_dentry;
	inode = dentry->d_inode;

	/* Ignore any mode updates on symlinks */
	if (S_ISLNK(inode->i_mode))
		iap->ia_valid &= ~ATTR_MODE;

	if (!iap->ia_valid)
		goto out;

	/* NFSv2 does not differentiate between "set-[ac]time-to-now"
	 * which only requires access, and "set-[ac]time-to-X" which
	 * requires ownership.
	 * So if it looks like it might be "set both to the same time which
	 * is close to now", and if inode_change_ok fails, then we
	 * convert to "set to now" instead of "set to explicit time"
	 *
	 * We only call inode_change_ok as the last test as technically
	 * it is not an interface that we should be using.  It is only
	 * valid if the filesystem does not define it's own i_op->setattr.
	 */
#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
#define	MAX_TOUCH_TIME_ERROR (30*60)
	if ((iap->ia_valid & BOTH_TIME_SET) == BOTH_TIME_SET
	    && iap->ia_mtime.tv_sec == iap->ia_atime.tv_sec
	    ) {
	    /* Looks probable.  Now just make sure time is in the right ballpark.
	     * Solaris, at least, doesn't seem to care what the time request is.
	     * We require it be within 30 minutes of now.
	     */
	    time_t delta = iap->ia_atime.tv_sec - get_seconds();
	    if (delta<0) delta = -delta;
	    if (delta < MAX_TOUCH_TIME_ERROR &&
		inode_change_ok(inode, iap) != 0) {
		/* turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME
		 * this will cause notify_change to set these times to "now"
		 */
		iap->ia_valid &= ~BOTH_TIME_SET;
	    }
	}
	    
	/* The size case is special. It changes the file as well as the attributes.  */
	if (iap->ia_valid & ATTR_SIZE) {
		if (iap->ia_size < inode->i_size) {
			err = nfsd_permission(fhp->fh_export, dentry, MAY_TRUNC|MAY_OWNER_OVERRIDE);
			if (err)
				goto out;
		}

		/*
		 * If we are changing the size of the file, then
		 * we need to break all leases.
		 */
		host_err = break_lease(inode, FMODE_WRITE | O_NONBLOCK);
		if (host_err == -EWOULDBLOCK)
			host_err = -ETIMEDOUT;
		if (host_err) /* ENOMEM or EWOULDBLOCK */
			goto out_nfserr;

		host_err = get_write_access(inode);
		if (host_err)
			goto out_nfserr;

		size_change = 1;
		host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
		if (host_err) {
			put_write_access(inode);
			goto out_nfserr;
		}
		DQUOT_INIT(inode);
	}

	imode = inode->i_mode;
	if (iap->ia_valid & ATTR_MODE) {
		iap->ia_mode &= S_IALLUGO;
		imode = iap->ia_mode |= (imode & ~S_IALLUGO);
	}

	/* Revoke setuid/setgid bit on chown/chgrp */
	if ((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid)
		iap->ia_valid |= ATTR_KILL_SUID;
	if ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid)
		iap->ia_valid |= ATTR_KILL_SGID;

	/* Change the attributes. */

	iap->ia_valid |= ATTR_CTIME;

	err = nfserr_notsync;
	if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
		fh_lock(fhp);
		host_err = notify_change(dentry, iap);
		err = nfserrno(host_err);
		fh_unlock(fhp);
	}
	if (size_change)
		put_write_access(inode);
	if (!err)
		if (EX_ISSYNC(fhp->fh_export))
			write_inode_now(inode, 1);
out:
	return err;

out_nfserr:
	err = nfserrno(host_err);
	goto out;
}
Example #2
0
static long do_sys_truncate(const char __user *pathname, loff_t length)
{
	struct path path;
	struct inode *inode;
	int error;

	error = -EINVAL;
	if (length < 0)	/* sorry, but loff_t says... */
		goto out;

	error = user_path(pathname, &path);
	if (error)
		goto out;
	inode = path.dentry->d_inode;

	/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
	error = -EISDIR;
	if (S_ISDIR(inode->i_mode))
		goto dput_and_out;

	error = -EINVAL;
	if (!S_ISREG(inode->i_mode))
		goto dput_and_out;

	error = mnt_want_write(path.mnt);
	if (error)
		goto dput_and_out;

	error = inode_permission(inode, MAY_WRITE);
	if (error)
		goto mnt_drop_write_and_out;

	error = -EPERM;
	if (IS_APPEND(inode))
		goto mnt_drop_write_and_out;

	error = get_write_access(inode);
	if (error)
		goto mnt_drop_write_and_out;

	/*
	 * Make sure that there are no leases.  get_write_access() protects
	 * against the truncate racing with a lease-granting setlease().
	 */
	error = break_lease(inode, O_WRONLY);
	if (error)
		goto put_write_and_out;

	error = locks_verify_truncate(inode, NULL, length);
	if (!error)
		error = security_path_truncate(&path, length, 0);
	if (!error)
		error = do_truncate(path.dentry, length, 0, NULL);

put_write_and_out:
	put_write_access(inode);
mnt_drop_write_and_out:
	mnt_drop_write(path.mnt);
dput_and_out:
	path_put(&path);
out:
	return error;
}
Example #3
0
File: open.c Project: 274914765/C
static long do_sys_truncate(const char __user * path, loff_t length)
{
    struct nameidata nd;
    struct inode * inode;
    int error;

    error = -EINVAL;
    if (length < 0)    /* sorry, but loff_t says... */
        goto out;

    error = user_path_walk(path, &nd);
    if (error)
        goto out;
    inode = nd.path.dentry->d_inode;

    /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
    error = -EISDIR;
    if (S_ISDIR(inode->i_mode))
        goto dput_and_out;

    error = -EINVAL;
    if (!S_ISREG(inode->i_mode))
        goto dput_and_out;

    error = mnt_want_write(nd.path.mnt);
    if (error)
        goto dput_and_out;

    error = vfs_permission(&nd, MAY_WRITE);
    if (error)
        goto mnt_drop_write_and_out;

    error = -EPERM;
    if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
        goto mnt_drop_write_and_out;

    error = get_write_access(inode);
    if (error)
        goto mnt_drop_write_and_out;

    /*
     * Make sure that there are no leases.  get_write_access() protects
     * against the truncate racing with a lease-granting setlease().
     */
    error = break_lease(inode, FMODE_WRITE);
    if (error)
        goto put_write_and_out;

    error = locks_verify_truncate(inode, NULL, length);
    if (!error) {
        DQUOT_INIT(inode);
        error = do_truncate(nd.path.dentry, length, 0, NULL);
    }

put_write_and_out:
    put_write_access(inode);
mnt_drop_write_and_out:
    mnt_drop_write(nd.path.mnt);
dput_and_out:
    path_put(&nd.path);
out:
    return error;
}