xref: /src/lib/librefuse/refuse.c

/*	$NetBSD: refuse.c,v 1.41 2007/03/13 20:50:47 agc Exp $	*/

/*
 * Copyright  2007 Alistair Crooks.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if !defined(lint)
__RCSID("$NetBSD: refuse.c,v 1.41 2007/03/13 20:50:47 agc Exp $");
#endif /* !lint */

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fuse.h>
#include <unistd.h>

#include "defs.h"

/*
This module implements refuse, a re-implementation of the FUSE model,
using puffs and libpuffs.  It is intended to be source code compatible
with FUSE.  Specifically, it implements FUSE versions 2.5 and 2.6,
although some effort was put in to make it backwards compatible (by
Antti, not me).

The error codes returned from refuse require some explanation.  Linux
error codes in the kernel are negative, whereas traditional NetBSD
error codes are positive.  For this reason, negative error codes are
returned from refuse, so that they are reported correctly to the
invoking application.
*/

typedef uint64_t	 fuse_ino_t;

struct fuse_config {
	uid_t		uid;
	gid_t		gid;
	mode_t		umask;
	double		entry_timeout;
	double		negative_timeout;
	double		attr_timeout;
	double		ac_attr_timeout;
	int		ac_attr_timeout_set;
	int		debug;
	int		hard_remove;
	int		use_ino;
	int		readdir_ino;
	int		set_mode;
	int		set_uid;
	int		set_gid;
	int		direct_io;
	int		kernel_cache;
	int		auto_cache;
	int		intr;
	int		intr_signal;
};

/* the fuse channel describes the physical attributes of the FUSE instance */
struct fuse_chan {
	const char		*dir;		/* directory */
	struct fuse_args	*args;		/* arguments to FUSE/puffs */
	struct puffs_usermount	*pu;		/* puffs information */
};

/* this is the private fuse structure */
struct fuse {
	struct fuse_chan	*fc;		/* fuse channel pointer */
	struct fuse_operations	op;		/* switch table of operations */
	int			compat;		/* compat level -
						 * not used in puffs_fuse */
	struct node		**name_table;
	size_t			name_table_size;
	struct node		**id_table;
	size_t			id_table_size;
	fuse_ino_t		ctr;
	unsigned int		generation;
	unsigned int		hidectr;
	pthread_mutex_t		lock;
	pthread_rwlock_t	tree_lock;
	void			*user_data;
	struct fuse_config	conf;
	int			intr_installed;
};

/* this struct describes a directory handle */
struct puffs_fuse_dirh {
	void		*dbuf;			/* directory buffer */
	struct dirent	*d;			/* pointer to its dirent */
	size_t		reslen;			/* result length */
	size_t		bufsize;		/* buffer size */
};

/* this struct describes a node in refuse land */
typedef struct refusenode {
	struct fuse_file_info	file_info;	/* file information */
	struct puffs_fuse_dirh	dirh;		/* directory handle */
	int			opencount;	/* # of times opened */
	int			flags;		/* associated flags */
} refusenode_t;
#define RN_ROOT		0x01
#define RN_OPEN		0x02	/* XXX: could just use opencount */

/* debugging functions */

/* change the debug level by increment */
int
__fuse_debug(int incr)
{
	static int	__fuse_debug_level;

	return __fuse_debug_level += incr;
}

/* print argv vector */
void
__fuse_pargs(const char *s, int argc, char **argv)
{
	int	i;

	for (i = 0 ; i < argc ; i++) {
		printf("%s: argv[%d] = `%s'\n", s, i, argv[i]);
	}
}


/* create a new struct puffs_node and return it */
static struct puffs_node *
newrn(struct puffs_usermount *pu)
{
	struct puffs_node *pn;
	struct refusenode *rn;

	NEW(struct refusenode, rn, "newrn", exit(EXIT_FAILURE));
	pn = puffs_pn_new(pu, rn);

	return pn;
}

/* destroy a struct puffs_node */
static void
nukern(struct puffs_node *pn)
{
	struct refusenode *rn = pn->pn_data;

	free(rn->dirh.dbuf);
	free(rn);
	puffs_pn_put(pn);
}

static ino_t fakeino = 3;

/*
 * XXX: do this differently if/when we grow thread support
 *
 * XXX2: does not consistently supply uid, gid or pid currently
 */
static struct fuse_context fcon;

#define DIR_CHUNKSIZE 4096
static int
fill_dirbuf(struct puffs_fuse_dirh *dh, const char *name, ino_t dino,
	uint8_t dtype)
{

	/* initial? */
	if (dh->bufsize == 0) {
		dh->dbuf = malloc(DIR_CHUNKSIZE);
		if (dh->dbuf == NULL) {
			err(EXIT_FAILURE, "fill_dirbuf");
		}
		dh->d = dh->dbuf;
		dh->reslen = dh->bufsize = DIR_CHUNKSIZE;
	}

	if (puffs_nextdent(&dh->d, name, dino, dtype, &dh->reslen)) {
		return 0;
	}

	/* try to increase buffer space */
	dh->dbuf = realloc(dh->dbuf, dh->bufsize + DIR_CHUNKSIZE);
	if (dh->dbuf == NULL) {
		err(EXIT_FAILURE, "fill_dirbuf realloc");
	}
	dh->d = (void *)((uint8_t *)dh->dbuf + (dh->bufsize - dh->reslen));
	dh->reslen += DIR_CHUNKSIZE;
	dh->bufsize += DIR_CHUNKSIZE;

	return !puffs_nextdent(&dh->d, name, dino, dtype, &dh->reslen);
}

/* ARGSUSED3 */
/* XXX: I have no idea how "off" is supposed to be used */
static int
puffs_fuse_fill_dir(void *buf, const char *name,
	const struct stat *stbuf, off_t off)
{
	struct puffs_fuse_dirh *deh = buf;
	ino_t dino;
	uint8_t dtype;

	if (stbuf == NULL) {
		dtype = DT_UNKNOWN;
		dino = fakeino++;
	} else {
		dtype = puffs_vtype2dt(puffs_mode2vt(stbuf->st_mode));
		dino = stbuf->st_ino;
	}

	return fill_dirbuf(deh, name, dino, dtype);
}

static int
puffs_fuse_dirfil(fuse_dirh_t h, const char *name, int type, ino_t ino)
{
	ino_t	dino;
	int	dtype;

	if ((dtype = type) == 0) {
		dtype = DT_UNKNOWN;
	}
	if ((dino = ino) == 0) {
		dino = fakeino++;
	}

	return fill_dirbuf(h, name, dino, dtype);
}

#define FUSE_ERR_UNLINK(fuse, file) if (fuse->op.unlink) fuse->op.unlink(file)
#define FUSE_ERR_RMDIR(fuse, dir) if (fuse->op.rmdir) fuse->op.rmdir(dir)

/* ARGSUSED1 */
static int
fuse_getattr(struct fuse *fuse, struct puffs_node *pn, const char *path,
	struct vattr *va)
{
	struct stat		 st;
	int			ret;

	if (fuse->op.getattr == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = (*fuse->op.getattr)(path, &st);

	if (ret == 0) {
		puffs_stat2vattr(va, &st);
	}

	return -ret;
}

static int
fuse_setattr(struct fuse *fuse, struct puffs_node *pn, const char *path,
	const struct vattr *va)
{
	struct refusenode	*rn = pn->pn_data;
	mode_t			mode;
	uid_t			uid;
	gid_t			gid;
	int			error, ret;

	error = 0;

	mode = va->va_mode;
	uid = va->va_uid;
	gid = va->va_gid;

	if (mode != (mode_t)PUFFS_VNOVAL) {
		ret = 0;

		if (fuse->op.chmod == NULL) {
			error = -ENOSYS;
		} else {
			ret = fuse->op.chmod(path, mode);
			if (ret)
				error = ret;
		}
	}
	if (uid != (uid_t)PUFFS_VNOVAL || gid != (gid_t)PUFFS_VNOVAL) {
		ret = 0;

		if (fuse->op.chown == NULL) {
			error = -ENOSYS;
		} else {
			ret = fuse->op.chown(path, uid, gid);
			if (ret)
				error = ret;
		}
	}
	if (va->va_atime.tv_sec != (time_t)PUFFS_VNOVAL
	    || va->va_mtime.tv_sec != (long)PUFFS_VNOVAL) {
		ret = 0;

		if (fuse->op.utimens) {
			struct timespec tv[2];

			tv[0].tv_sec = va->va_atime.tv_sec;
			tv[0].tv_nsec = va->va_atime.tv_nsec;
			tv[1].tv_sec = va->va_mtime.tv_sec;
			tv[1].tv_nsec = va->va_mtime.tv_nsec;

			ret = fuse->op.utimens(path, tv);
		} else if (fuse->op.utime) {
			struct utimbuf timbuf;

			timbuf.actime = va->va_atime.tv_sec;
			timbuf.modtime = va->va_mtime.tv_sec;

			ret = fuse->op.utime(path, &timbuf);
		} else {
			error = -ENOSYS;
		}

		if (ret)
			error = ret;
	}
	if (va->va_size != (u_quad_t)PUFFS_VNOVAL) {
		ret = 0;

		if (fuse->op.truncate) {
			ret = fuse->op.truncate(path, (off_t)va->va_size);
		} else if (fuse->op.ftruncate) {
			ret = fuse->op.ftruncate(path, (off_t)va->va_size,
			    &rn->file_info);
		} else {
			error = -ENOSYS;
		}

		if (ret)
			error = ret;
	}
	/* XXX: no reflection with reality */
	puffs_setvattr(&pn->pn_va, va);

	return -error;

}

static int
fuse_newnode(struct puffs_usermount *pu, const char *path,
	const struct vattr *va, struct fuse_file_info *fi, void **newnode)
{
	struct vattr		newva;
	struct fuse		*fuse;
	struct puffs_node	*pn;
	struct refusenode	*rn;

	fuse = (struct fuse *)pu->pu_privdata;

	/* fix up nodes */
	pn = newrn(pu);
	if (pn == NULL) {
		if (va->va_type == VDIR) {
			FUSE_ERR_RMDIR(fuse, path);
		} else {
			FUSE_ERR_UNLINK(fuse, path);
		}
		return ENOMEM;
	}
	fuse_setattr(fuse, pn, path, va);
	if (fuse_getattr(fuse, pn, path, &newva) == 0)
		puffs_setvattr(&pn->pn_va, &newva);

	rn = pn->pn_data;
	if (fi)
		memcpy(&rn->file_info, fi, sizeof(struct fuse_file_info));

	*newnode = pn;

	return 0;
}


/* operation wrappers start here */

/* lookup the path */
/* ARGSUSED1 */
static int
puffs_fuse_node_lookup(struct puffs_cc *pcc, void *opc, void **newnode,
	enum vtype *newtype, voff_t *newsize, dev_t *newrdev,
	const struct puffs_cn *pcn)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn_res;
	struct stat		st;
	struct fuse		*fuse;
	const char		*path = PCNPATH(pcn);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	ret = fuse->op.getattr(path, &st);

	if (ret != 0) {
		return -ret;
	}

	/* XXX: fiXXXme unconst */
	pn_res = puffs_pn_nodewalk(pu, puffs_path_walkcmp,
	    __UNCONST(&pcn->pcn_po_full));
	if (pn_res == NULL) {
		pn_res = newrn(pu);
		if (pn_res == NULL)
			return errno;
		puffs_stat2vattr(&pn_res->pn_va, &st);
	}

	*newnode = pn_res;
	*newtype = pn_res->pn_va.va_type;
	*newsize = pn_res->pn_va.va_size;
	*newrdev = pn_res->pn_va.va_rdev;

	return 0;
}

/* get attributes for the path name */
/* ARGSUSED3 */
static int
puffs_fuse_node_getattr(struct puffs_cc *pcc, void *opc, struct vattr *va,
	const struct puffs_cred *pcr, pid_t pid)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = opc;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn);

	fuse = (struct fuse *)pu->pu_privdata;
	return fuse_getattr(fuse, pn, path, va);
}

/* read the contents of the symbolic link */
/* ARGSUSED2 */
static int
puffs_fuse_node_readlink(struct puffs_cc *pcc, void *opc,
	const struct puffs_cred *cred, char *linkname, size_t *linklen)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = opc;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn), *p;
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.readlink == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = (*fuse->op.readlink)(path, linkname, *linklen);

	if (ret == 0) {
		p = memchr(linkname, 0x0, *linklen);
		if (!p)
			return EINVAL;

		*linklen = p - linkname;
	}

	return -ret;
}

/* make the special node */
/* ARGSUSED1 */
static int
puffs_fuse_node_mknod(struct puffs_cc *pcc, void *opc, void **newnode,
	const struct puffs_cn *pcn, const struct vattr *va)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct fuse		*fuse;
	mode_t			 mode = va->va_mode;
	const char		*path = PCNPATH(pcn);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.mknod == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = (*fuse->op.mknod)(path, mode, va->va_rdev);

	if (ret == 0) {
		ret = fuse_newnode(pu, path, va, NULL, newnode);
	}

	return -ret;
}

/* make a directory */
/* ARGSUSED1 */
static int
puffs_fuse_node_mkdir(struct puffs_cc *pcc, void *opc, void **newnode,
	const struct puffs_cn *pcn, const struct vattr *va)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct fuse		*fuse;
	mode_t			 mode = va->va_mode;
	const char		*path = PCNPATH(pcn);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.mkdir == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = (*fuse->op.mkdir)(path, mode);

	if (ret == 0) {
		ret = fuse_newnode(pu, path, va, NULL, newnode);
	}

	return -ret;
}

/*
 * create a regular file
 *
 * since linux/fuse sports using mknod for creating regular files
 * instead of having a separate call for it in some versions, if
 * we don't have create, just jump to op->mknod.
 */
/*ARGSUSED1*/
static int
puffs_fuse_node_create(struct puffs_cc *pcc, void *opc, void **newnode,
	const struct puffs_cn *pcn, const struct vattr *va)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct fuse		*fuse;
	struct fuse_file_info	fi;
	mode_t			mode = va->va_mode;
	const char		*path = PCNPATH(pcn);
	int			ret, created;

	fuse = (struct fuse *)pu->pu_privdata;

	created = 0;
	if (fuse->op.create) {
		ret = fuse->op.create(path, mode, &fi);
		if (ret == 0)
			created = 1;

	} else if (fuse->op.mknod) {
		fcon.uid = va->va_uid; /*XXX*/
		fcon.gid = va->va_gid; /*XXX*/

		ret = fuse->op.mknod(path, mode | S_IFREG, 0);

	} else {
		ret = -ENOSYS;
	}

	if (ret == 0) {
		ret = fuse_newnode(pu, path, va, &fi, newnode);

		/* sweet..  create also open the file */
		if (created) {
			struct puffs_node *pn;
			struct refusenode *rn;

			pn = *newnode;
			rn = pn->pn_data;
			rn->flags |= RN_OPEN;
			rn->opencount++;
		}
	}

	return -ret;
}

/* remove the directory entry */
/* ARGSUSED1 */
static int
puffs_fuse_node_remove(struct puffs_cc *pcc, void *opc, void *targ,
	const struct puffs_cn *pcn)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn_targ = targ;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn_targ);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.unlink == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = (*fuse->op.unlink)(path);

	return -ret;
}

/* remove the directory */
/* ARGSUSED1 */
static int
puffs_fuse_node_rmdir(struct puffs_cc *pcc, void *opc, void *targ,
	const struct puffs_cn *pcn)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn_targ = targ;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn_targ);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.rmdir == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = (*fuse->op.rmdir)(path);

	return -ret;
}

/* create a symbolic link */
/* ARGSUSED1 */
static int
puffs_fuse_node_symlink(struct puffs_cc *pcc, void *opc, void **newnode,
	const struct puffs_cn *pcn_src, const struct vattr *va,
	const char *link_target)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct fuse		*fuse;
	const char		*path = PCNPATH(pcn_src);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.symlink == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = fuse->op.symlink(link_target, path);

	if (ret == 0) {
		ret = fuse_newnode(pu, path, va, NULL, newnode);
	}

	return -ret;
}

/* rename a directory entry */
/* ARGSUSED1 */
static int
puffs_fuse_node_rename(struct puffs_cc *pcc, void *opc, void *src,
	const struct puffs_cn *pcn_src, void *targ_dir, void *targ,
	const struct puffs_cn *pcn_targ)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct fuse		*fuse;
	const char		*path_src = PCNPATH(pcn_src);
	const char		*path_dest = PCNPATH(pcn_targ);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.rename == NULL) {
		return ENOSYS;
	}

	ret = fuse->op.rename(path_src, path_dest);

	if (ret == 0) {
	}

	return -ret;
}

/* create a link in the file system */
/* ARGSUSED1 */
static int
puffs_fuse_node_link(struct puffs_cc *pcc, void *opc, void *targ,
	const struct puffs_cn *pcn)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = targ;
	struct fuse		*fuse;
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.link == NULL) {
		return ENOSYS;
	}

	/* wrap up return code */
	ret = (*fuse->op.link)(PNPATH(pn), PCNPATH(pcn));

	return -ret;
}

/*
 * fuse's regular interface provides chmod(), chown(), utimes()
 * and truncate() + some variations, so try to fit the square block
 * in the circle hole and the circle block .... something like that
 */
/* ARGSUSED3 */
static int
puffs_fuse_node_setattr(struct puffs_cc *pcc, void *opc,
	const struct vattr *va, const struct puffs_cred *pcr, pid_t pid)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = opc;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn);

	fuse = (struct fuse *)pu->pu_privdata;

	return fuse_setattr(fuse, pn, path, va);
}

/* ARGSUSED2 */
static int
puffs_fuse_node_open(struct puffs_cc *pcc, void *opc, int mode,
	const struct puffs_cred *cred, pid_t pid)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = opc;
	struct refusenode	*rn = pn->pn_data;
	struct fuse_file_info	*fi = &rn->file_info;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn);

	fuse = (struct fuse *)pu->pu_privdata;

	/* if open, don't open again, lest risk nuking file private info */
	if (rn->flags & RN_OPEN) {
		rn->opencount++;
		return 0;
	}

	/* OFLAGS(), need to convert FREAD/FWRITE to O_RD/WR */
	fi->flags = (mode & ~(O_CREAT | O_EXCL | O_TRUNC)) - 1;

	if (pn->pn_va.va_type == VDIR) {
		if (fuse->op.opendir)
			fuse->op.opendir(path, fi);
	} else {
		if (fuse->op.open)
			fuse->op.open(path, fi);
	}

	rn->flags |= RN_OPEN;
	rn->opencount++;

	return 0;
}

/* ARGSUSED2 */
static int
puffs_fuse_node_close(struct puffs_cc *pcc, void *opc, int fflag,
	const struct puffs_cred *pcr, pid_t pid)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = opc;
	struct refusenode	*rn = pn->pn_data;
	struct fuse		*fuse;
	struct fuse_file_info	*fi;
	const char		*path = PNPATH(pn);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	fi = &rn->file_info;
	ret = 0;

	if (rn->flags & RN_OPEN) {
		if (pn->pn_va.va_type == VDIR) {
			if (fuse->op.releasedir)
				ret = fuse->op.releasedir(path, fi);
		} else {
			if (fuse->op.release)
				ret = fuse->op.release(path, fi);
		}
	}
	rn->flags &= ~RN_OPEN;
	rn->opencount--;

	return ret;
}

/* read some more from the file */
/* ARGSUSED5 */
static int
puffs_fuse_node_read(struct puffs_cc *pcc, void *opc, uint8_t *buf,
	off_t offset, size_t *resid, const struct puffs_cred *pcr,
	int ioflag)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = opc;
	struct refusenode	*rn = pn->pn_data;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn);
	size_t			maxread;
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.read == NULL) {
		return ENOSYS;
	}

	maxread = *resid;
	if (maxread > pn->pn_va.va_size - offset) {
		/*LINTED*/
		maxread = pn->pn_va.va_size - offset;
	}
	if (maxread == 0)
		return 0;

	ret = (*fuse->op.read)(path, (char *)buf, maxread, offset,
	    &rn->file_info);

	if (ret > 0) {
		*resid -= ret;
		ret = 0;
	}

	return -ret;
}

/* write to the file */
/* ARGSUSED0 */
static int
puffs_fuse_node_write(struct puffs_cc *pcc, void *opc, uint8_t *buf,
	off_t offset, size_t *resid, const struct puffs_cred *pcr,
	int ioflag)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_node	*pn = opc;
	struct refusenode	*rn = pn->pn_data;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.write == NULL) {
		return ENOSYS;
	}

	if (ioflag & PUFFS_IO_APPEND)
		offset = pn->pn_va.va_size;

	ret = (*fuse->op.write)(path, (char *)buf, *resid, offset,
	    &rn->file_info);

	if (ret > 0) {
		if (offset + ret > pn->pn_va.va_size)
			pn->pn_va.va_size = offset + ret;
		*resid -= ret;
		ret = 0;
	}

	return -ret;
}


/* ARGSUSED3 */
static int
puffs_fuse_node_readdir(struct puffs_cc *pcc, void *opc,
	struct dirent *dent, const struct puffs_cred *pcr, off_t *readoff,
	size_t *reslen)
{
	struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct puffs_fuse_dirh	*dirh;
	struct puffs_node	*pn = opc;
	struct refusenode	*rn = pn->pn_data;
	struct dirent		*fromdent;
	struct fuse		*fuse;
	const char		*path = PNPATH(pn);
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.readdir == NULL && fuse->op.getdir == NULL) {
		return ENOSYS;
	}

	if (pn->pn_va.va_type != VDIR)
		return ENOTDIR;

	dirh = &rn->dirh;

	/*
	 * if we are starting from the beginning, slurp entire directory
	 * into our buffers
	 */
	if (*readoff == 0) {
		/* free old buffers */
		free(dirh->dbuf);
		memset(dirh, 0, sizeof(struct puffs_fuse_dirh));

		if (fuse->op.readdir)
			ret = fuse->op.readdir(path, dirh, puffs_fuse_fill_dir,
			    0, &rn->file_info);
		else
			ret = fuse->op.getdir(path, dirh, puffs_fuse_dirfil);
		if (ret)
			return -ret;
	}

	/* now, stuff results into the kernel buffers */
	while (*readoff < dirh->bufsize - dirh->reslen) {
		/*LINTED*/
		fromdent = (struct dirent *)((uint8_t *)dirh->dbuf + *readoff);

		if (*reslen < _DIRENT_SIZE(fromdent))
			break;

		memcpy(dent, fromdent, _DIRENT_SIZE(fromdent));
		*readoff += _DIRENT_SIZE(fromdent);
		*reslen -= _DIRENT_SIZE(fromdent);

		dent = _DIRENT_NEXT(dent);
	}

	return 0;
}

/* ARGSUSED */
static int
puffs_fuse_node_reclaim(struct puffs_cc *pcc, void *opc, pid_t pid)
{
	struct puffs_node	*pn = opc;

	nukern(pn);

	return 0;
}

/* ARGSUSED1 */
static int
puffs_fuse_fs_unmount(struct puffs_cc *pcc, int flags, pid_t pid)
{
        struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct fuse		*fuse;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.destroy == NULL) {
		return 0;
	}
	(*fuse->op.destroy)(fuse);
        return 0;
}

/* ARGSUSED0 */
static int
puffs_fuse_fs_sync(struct puffs_cc *pcc, int flags,
            const struct puffs_cred *cr, pid_t pid)
{
        return 0;
}

/* ARGSUSED2 */
static int
puffs_fuse_fs_statvfs(struct puffs_cc *pcc, struct statvfs *svfsb, pid_t pid)
{
        struct puffs_usermount	*pu = puffs_cc_getusermount(pcc);
	struct fuse		*fuse;
	int			ret;

	fuse = (struct fuse *)pu->pu_privdata;
	if (fuse->op.statfs == NULL) {
#ifdef REFUSE_INHERIT_FS_CHARACTERISTICS
		if ((ret = statvfs(PNPATH(pu->pu_pn_root), svfsb)) == -1) {
			return errno;
		}
#else
		(void) memset(svfsb, 0x0, sizeof(*svfsb));
		ret = 0;
#endif
	} else {
		ret = (*fuse->op.statfs)(PNPATH(pu->pu_pn_root), svfsb);
	}

        return ret;
}


/* End of puffs_fuse operations */


/* ARGSUSED3 */
int
fuse_main_real(int argc, char **argv, const struct fuse_operations *ops,
	size_t size, void *userdata)
{
	struct fuse_chan	*fc;
	struct fuse_args	 args;
	struct fuse		*fuse;
	int			 ret;

	(void) memset(&args, 0x0, sizeof(args));
	args.argc = argc;
	args.argv = argv;

	if (__fuse_debug(0)) {
		__fuse_pargs("fuse_main_real", argc, argv);
	}
	fc = fuse_mount(argv[argc - 1], &args);
	/* XXX: stuff name into fuse_args */
	fuse = fuse_new(fc, fc->args, ops, size, userdata);

	ret = fuse_loop(fuse);

	return ret;
}

/*
 * XXX: just defer the operation until fuse_new() when we have more
 * info on our hands.  The real beef is why's this separate in fuse in
 * the first place?
 */
/* ARGSUSED1 */
struct fuse_chan *
fuse_mount(const char *dir, struct fuse_args *args)
{
	struct fuse_chan	*fc;
	int			i;

	NEW(struct fuse_chan, fc, "fuse_mount", return NULL);

	fc->dir = strdup(dir);

	if (args && args->argc > 0) {
		NEW(struct fuse_args, fc->args, "fuse_mount2", return NULL);

		/* yes, we do need to deep copy */
		fc->args->allocated = ((args->argc / 32) + 1) * 32;
		NEWARRAY(char *, fc->args->argv, fc->args->allocated, "fuse_mount3", return NULL);

		for (i = 0 ; i < args->argc ; i++) {
			fc->args->argv[i] = strdup(args->argv[i]);
		}
	}

	return fc;
}

/* ARGSUSED1 */
struct fuse *
fuse_new(struct fuse_chan *fc, struct fuse_args *args,
	const struct fuse_operations *ops, size_t size, void *userdata)
{
	struct puffs_usermount	*pu;
	struct puffs_pathobj	*po_root;
	struct refusenode	*rn_root;
	struct puffs_ops	*pops;
	struct statvfs		svfsb;
	struct stat		st;
	struct fuse		*fuse;
	char			 name[64];
	char			*slash;

	NEW(struct fuse, fuse, "fuse_new", exit(EXIT_FAILURE));

	/* copy fuse ops to their own stucture */
	(void) memcpy(&fuse->op, ops, sizeof(fuse->op));

	fcon.fuse = fuse;
	fcon.private_data = userdata;

	fuse->fc = fc;

	/* initialise the puffs operations structure */
        PUFFSOP_INIT(pops);

        PUFFSOP_SET(pops, puffs_fuse, fs, sync);
        PUFFSOP_SET(pops, puffs_fuse, fs, statvfs);
        PUFFSOP_SET(pops, puffs_fuse, fs, unmount);

	/*
	 * XXX: all of these don't possibly need to be
	 * unconditionally set
	 */
        PUFFSOP_SET(pops, puffs_fuse, node, lookup);
        PUFFSOP_SET(pops, puffs_fuse, node, getattr);
        PUFFSOP_SET(pops, puffs_fuse, node, setattr);
        PUFFSOP_SET(pops, puffs_fuse, node, readdir);
        PUFFSOP_SET(pops, puffs_fuse, node, readlink);
        PUFFSOP_SET(pops, puffs_fuse, node, mknod);
        PUFFSOP_SET(pops, puffs_fuse, node, create);
        PUFFSOP_SET(pops, puffs_fuse, node, remove);
        PUFFSOP_SET(pops, puffs_fuse, node, mkdir);
        PUFFSOP_SET(pops, puffs_fuse, node, rmdir);
        PUFFSOP_SET(pops, puffs_fuse, node, symlink);
        PUFFSOP_SET(pops, puffs_fuse, node, rename);
        PUFFSOP_SET(pops, puffs_fuse, node, link);
        PUFFSOP_SET(pops, puffs_fuse, node, open);
        PUFFSOP_SET(pops, puffs_fuse, node, close);
        PUFFSOP_SET(pops, puffs_fuse, node, read);
        PUFFSOP_SET(pops, puffs_fuse, node, write);
        PUFFSOP_SET(pops, puffs_fuse, node, reclaim);

	/* work out what we'll call ourselves in df output */
	if (args == NULL) {
		args = fc->args;
	}
	if (args == NULL || args->argv == NULL || args->argv[0] == NULL) {
		(void) strlcpy(name, "refuse", sizeof(name));
	} else {
		if ((slash = strrchr(*args->argv, '/')) == NULL) {
			slash = *args->argv;
		} else {
			slash += 1;
		}
		(void) snprintf(name, sizeof(name), "refuse:%s", slash);
	}

	pu = puffs_mount(pops, fc->dir, MNT_NODEV | MNT_NOSUID,
			 name, NULL,
			 PUFFS_FLAG_BUILDPATH
			   | PUFFS_FLAG_OPDUMP
			   | PUFFS_KFLAG_NOCACHE,
			 0);
	if (pu == NULL) {
		err(EXIT_FAILURE, "puffs_mount");
	}
	fc->pu = pu;
	/* whilst this (assigning the pu_privdata in the puffs
	 * usermount struct to be the fuse struct) might seem like
	 * we are chasing our tail here, the logic is as follows:
		+ the operation wrapper gets called with the puffs
		  calling conventions
		+ we need to fix up args first
		+ then call the fuse user-supplied operation
		+ then we fix up any values on return that we need to
		+ and fix up any nodes, etc
	 * so we need to be able to get at the fuse ops from within the
	 * puffs_usermount struct
	 */
	pu->pu_privdata = fuse;

	pu->pu_pn_root = newrn(pu);
	rn_root = pu->pu_pn_root->pn_data;
	rn_root->flags |= RN_ROOT;

	po_root = puffs_getrootpathobj(pu);
	po_root->po_path = strdup("/");
	po_root->po_len = 1;

	/* sane defaults */
	puffs_vattr_null(&pu->pu_pn_root->pn_va);
	pu->pu_pn_root->pn_va.va_type = VDIR;
	pu->pu_pn_root->pn_va.va_mode = 0755;
	if (fuse->op.getattr)
		if (fuse->op.getattr(po_root->po_path, &st) == 0)
			puffs_stat2vattr(&pu->pu_pn_root->pn_va, &st);
	assert(pu->pu_pn_root->pn_va.va_type == VDIR);

	if (fuse->op.init)
		fcon.private_data = fuse->op.init(NULL); /* XXX */

	puffs_zerostatvfs(&svfsb);
	if (puffs_start(pu, pu->pu_pn_root, &svfsb) == -1) {
		err(EXIT_FAILURE, "puffs_start");
	}

	return fuse;
}

int
fuse_loop(struct fuse *fuse)
{

	return puffs_mainloop(fuse->fc->pu, PUFFSLOOP_NODAEMON);
}

void
fuse_destroy(struct fuse *fuse)
{


	/* XXXXXX: missing stuff */
	FREE(fuse);
}

/* XXX: threads */
struct fuse_context *
fuse_get_context()
{

	return &fcon;
}

void
fuse_exit(struct fuse *fuse)
{

	puffs_exit(fuse->fc->pu, 1);
}

/*
 * XXX: obviously not the most perfect of functions, but needs some
 * puffs tweaking for a better tomorrow
 */
/*ARGSUSED*/
void
fuse_unmount(const char *mp, struct fuse_chan *fc)
{

	puffs_exit(fc->pu, 1);
}

/*ARGSUSED*/
void
fuse_unmount_compat22(const char *mp)
{

	return;
}