Remove building with NOCRYPTO option

[minix3.git] / lib / librefuse / refuse.c

/*      $NetBSD: refuse.c,v 1.96 2012/12/30 10:04:22 tron Exp $ */

/*
 * Copyright © 2007 Alistair Crooks.  All rights reserved.
 * Copyright © 2007 Antti Kantee.  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 1.96 2012/12/30 10:04:22 tron Exp $");
#endif /* !lint */

#include <sys/types.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fuse.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifdef MULTITHREADED_REFUSE
#include <pthread.h>
#endif

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;
};

struct fuse_chan {
        const char              *dir;
        struct fuse_args        *args;
        struct puffs_usermount  *pu;
        int                     dead;
};

/* 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;
#if !defined(__minix)
        pthread_mutex_t         lock;
        pthread_rwlock_t        tree_lock;
#endif /* !defined(__minix) */
        void                    *user_data;
        struct fuse_config      conf;
        int                     intr_installed;
};

struct puffs_fuse_dirh {
        void *dbuf;
        struct dirent *d;

        size_t reslen;
        size_t bufsize;
};

struct refusenode {
        struct fuse_file_info   file_info;
        struct puffs_fuse_dirh  dirh;
        int opencount;
        int flags;
};
#define RN_ROOT         0x01
#define RN_OPEN         0x02    /* XXX: could just use opencount */

static int fuse_setattr(struct fuse *, struct puffs_node *,
                        const char *, const struct vattr *);

static struct puffs_node *
newrn(struct puffs_usermount *pu)
{
        struct puffs_node *pn;
        struct refusenode *rn;

        if ((rn = calloc(1, sizeof(*rn))) == NULL) {
                err(EXIT_FAILURE, "newrn");
        }
        pn = puffs_pn_new(pu, rn);

        return pn;
}

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

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

/* XXX - not threadsafe */
static ino_t fakeino = 3;

/***************** start of pthread context routines ************************/

/*
 * Notes on fuse_context:
 * we follow fuse's lead and use the pthread specific information to hold
 * a reference to the fuse_context structure for this thread.
 */
#ifdef MULTITHREADED_REFUSE
static pthread_mutex_t          context_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_key_t            context_key;
static unsigned long            context_refc;
#endif

/* return the fuse_context struct related to this thread */
struct fuse_context *
fuse_get_context(void)
{
#ifdef MULTITHREADED_REFUSE
        struct fuse_context     *ctxt;

        if ((ctxt = pthread_getspecific(context_key)) == NULL) {
                if ((ctxt = calloc(1, sizeof(struct fuse_context))) == NULL) {
                        abort();
                }
                pthread_setspecific(context_key, ctxt);
        }
        return ctxt;
#else
        static struct fuse_context      fcon;

        return &fcon;
#endif
}

/* used as a callback function */
#ifdef MULTITHREADED_REFUSE
static void
free_context(void *ctxt)
{   
        free(ctxt);
}
#endif

/*
 * Create the pthread key.  The reason for the complexity is to
 * enable use of multiple fuse instances within a single process.
 */
static int
create_context_key(void)
{   
#ifdef MULTITHREADED_REFUSE
        int rv;

        rv = pthread_mutex_lock(&context_mutex);
        assert(rv == 0);

        if (context_refc == 0) {
                if (pthread_key_create(&context_key, free_context) != 0) {
                        warnx("create_context_key: pthread_key_create failed");
                        pthread_mutex_unlock(&context_mutex);
                        return 0;
                }
        }
        context_refc += 1;
        pthread_mutex_unlock(&context_mutex);
        return 1;
#else
        return 1;
#endif
}

static void
delete_context_key(void)
{   
#ifdef MULTITHREADED_REFUSE
        pthread_mutex_lock(&context_mutex);
        /* If we are the last fuse instances using the key, delete it */
        if (--context_refc == 0) {
                free(pthread_getspecific(context_key));
                pthread_key_delete(context_key);
        }
        pthread_mutex_unlock(&context_mutex);
#endif
}

/* set the uid and gid of the calling process in the current fuse context */
static void
set_fuse_context_uid_gid(const struct puffs_cred *cred)
{
        struct fuse_context     *fusectx;
        uid_t                    uid;
        gid_t                    gid;

        fusectx = fuse_get_context();
        if (puffs_cred_getuid(cred, &uid) == 0) {
                fusectx->uid = uid;
        }
        if (puffs_cred_getgid(cred, &gid) == 0) {
                fusectx->gid = gid;
        }
}

/* set the pid of the calling process in the current fuse context */
static void
set_fuse_context_pid(struct puffs_usermount *pu)
{
        struct puffs_cc         *pcc = puffs_cc_getcc(pu);
        struct fuse_context     *fusectx;

        fusectx = fuse_get_context();
        puffs_cc_getcaller(pcc, &fusectx->pid, NULL);
}

/***************** end of pthread context routines ************************/

#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) {
                if ((dh->dbuf = calloc(1, DIR_CHUNKSIZE)) == NULL) {
                        abort();
                }
                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) {
                abort();
        }
        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;

                /*
                 * Some FUSE file systems like to always use 0 as the
                 * inode number.   Our readdir() doesn't like to show
                 * directory entries with inode number 0 ==> workaround.
                 */
                if (dino == 0) {
                        dino = fakeino++;
                }
        }

        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;
        }

        dino = (ino) ? ino : fakeino++;

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

/* place the refuse file system name into `name' */
static void
set_refuse_mount_name(char **argv, char *name, size_t size)
{
        char    *slash;

        if (argv == NULL || *argv == NULL) {
                (void) strlcpy(name, "refuse", size);
        } else {
                if ((slash = strrchr(*argv, '/')) == NULL) {
                        slash = *argv;
                } else {
                        slash += 1;
                }
                if (strncmp(*argv, "refuse:", 7) == 0) {
                        /* we've already done this */
                        (void) strlcpy(name, *argv, size);
                } else {
                        (void) snprintf(name, size, "refuse:%s", slash);
                }
        }
}


/* this function exposes struct fuse to userland */
static struct fuse *
fuse_setup_real(int argc, char **argv, const struct fuse_operations *ops,
        size_t size, char **mountpoint, int *multithreaded, int *fd,
        void *user_data)
{
        struct fuse_chan        *fc;
        struct fuse_args        *args;
        struct fuse             *fuse;
        char                     name[64];
        int                      i;

        /* set up the proper name */
        set_refuse_mount_name(argv, name, sizeof(name));

        /* grab the pthread context key */
        if (!create_context_key()) {
                return NULL;
        }

        /* stuff name into fuse_args */
        args = fuse_opt_deep_copy_args(argc, argv);
        if (args->argc > 0) {
                free(args->argv[0]);
        }
        if ((args->argv[0] = strdup(name)) == NULL) {
                fuse_opt_free_args(args);
                return NULL;
        }

        /* count back from the end over arguments starting with '-' */
        for (i = argc - 1 ; i > 0 && *argv[i] == '-' ; --i) {
        }

        fc = fuse_mount(*mountpoint = argv[i], args);
        fuse = fuse_new(fc, args, ops, size, user_data);

        fuse_opt_free_args(args);
        free(args);

        /* XXX - wait for puffs to become multi-threaded */
        if (multithreaded) {
                *multithreaded = 0;
        }

        /* XXX - this is unused */
        if (fd) {
                *fd = 0;
        }

        return fuse;
}

#ifdef fuse_setup
#undef fuse_setup
#endif

struct fuse *
fuse_setup(int argc, char **argv, const struct fuse_operations *ops,
        size_t size, char **mountpoint, int *multithreaded, int *fd)
{
    return fuse_setup_real(argc, argv, ops, size, mountpoint,
        multithreaded, fd, NULL);
}

struct fuse *
fuse_setup26(int argc, char **argv, const struct fuse_operations *ops,
        size_t size, char **mountpoint, int *multithreaded, void *user_data)
{
    return fuse_setup_real(argc, argv, ops, size, mountpoint,
        multithreaded, NULL, user_data);
}

#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 */
        memset(&st, 0, sizeof(st));
        ret = (*fuse->op.getattr)(path, &st);

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

        return -ret;
}

/* utility function to set various elements of the attribute */
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,
        struct puffs_newinfo *pni, struct puffs_node **pn_new)
{
        struct puffs_node       *pn;
        struct refusenode       *rn;
        struct vattr             newva;
        struct fuse             *fuse;

        fuse = puffs_getspecific(pu);

        /* 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));

        puffs_newinfo_setcookie(pni, pn);
        if (pn_new)
                *pn_new = pn;

        return 0;
}


/* operation wrappers start here */

/* lookup the path */
/* ARGSUSED1 */
static int
puffs_fuse_node_lookup(struct puffs_usermount *pu, void *opc,
        struct puffs_newinfo *pni, const struct puffs_cn *pcn)
{
        struct puffs_node       *pn_res;
        struct stat              st;
        struct fuse             *fuse;
        const char              *path = PCNPATH(pcn);
        int                      ret;

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn->pcn_cred);

        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);
        }

        puffs_newinfo_setcookie(pni, pn_res);
        puffs_newinfo_setvtype(pni, pn_res->pn_va.va_type);
        puffs_newinfo_setsize(pni, (voff_t)pn_res->pn_va.va_size);
        puffs_newinfo_setrdev(pni, pn_res->pn_va.va_rdev);

        return 0;
}

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

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcr);

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

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

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

        set_fuse_context_uid_gid(cred);

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

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

                *linklen = p - linkname;
        }

        return -ret;
}

/* make the special node */
/* ARGSUSED1 */
static int
puffs_fuse_node_mknod(struct puffs_usermount *pu, void *opc,
        struct puffs_newinfo *pni, const struct puffs_cn *pcn,
        const struct vattr *va)
{
        struct fuse             *fuse;
        mode_t                   mode;
        const char              *path = PCNPATH(pcn);
        int                     ret;

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

        set_fuse_context_uid_gid(pcn->pcn_cred);

        /* wrap up return code */
        mode = puffs_addvtype2mode(va->va_mode, va->va_type);
        ret = (*fuse->op.mknod)(path, mode, va->va_rdev);

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

        return -ret;
}

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

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn->pcn_cred);

        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, pni, NULL);
        }

        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_usermount *pu, void *opc,
        struct puffs_newinfo *pni, const struct puffs_cn *pcn,
        const struct vattr *va)
{
        struct fuse             *fuse;
        struct fuse_file_info   fi;
        struct puffs_node       *pn;
        mode_t                  mode = va->va_mode;
        const char              *path = PCNPATH(pcn);
        int                     ret, created;

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn->pcn_cred);

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

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

        } else {
                ret = -ENOSYS;
        }

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

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

                        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_usermount *pu, void *opc, void *targ,
        const struct puffs_cn *pcn)
{
        struct puffs_node       *pn_targ = targ;
        struct fuse             *fuse;
        const char              *path = PNPATH(pn_targ);
        int                     ret;

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn->pcn_cred);

        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_usermount *pu, void *opc, void *targ,
        const struct puffs_cn *pcn)
{
        struct puffs_node       *pn_targ = targ;
        struct fuse             *fuse;
        const char              *path = PNPATH(pn_targ);
        int                     ret;

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn->pcn_cred);

        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_usermount *pu, void *opc,
        struct puffs_newinfo *pni, const struct puffs_cn *pcn_src,
        const struct vattr *va, const char *link_target)
{
        struct fuse             *fuse;
        const char              *path = PCNPATH(pcn_src);
        int                     ret;

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn_src->pcn_cred);

        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, pni, NULL);
        }

        return -ret;
}

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

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn_targ->pcn_cred);

        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_usermount *pu, void *opc, void *targ,
        const struct puffs_cn *pcn)
{
        struct puffs_node       *pn = targ;
        struct fuse             *fuse;
        int                     ret;

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcn->pcn_cred);

        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_usermount *pu, void *opc,
        const struct vattr *va, const struct puffs_cred *pcr)
{
        struct puffs_node       *pn = opc;
        struct fuse             *fuse;
        const char              *path = PNPATH(pn);

        fuse = puffs_getspecific(pu);

        set_fuse_context_uid_gid(pcr);

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

/* ARGSUSED2 */
static int
puffs_fuse_node_open(struct puffs_usermount *pu, void *opc, int mode,
        const struct puffs_cred *cred)
{
        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 = puffs_getspecific(pu);

        set_fuse_context_uid_gid(cred);

        /* 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_usermount *pu, void *opc, int fflag,
        const struct puffs_cred *pcr)
{
        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 = puffs_getspecific(pu);
        fi = &rn->file_info;
        ret = 0;

        set_fuse_context_uid_gid(pcr);

        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_usermount *pu, void *opc, uint8_t *buf,
        off_t offset, size_t *resid, const struct puffs_cred *pcr,
        int ioflag)
{
        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 = puffs_getspecific(pu);
        if (fuse->op.read == NULL) {
                return ENOSYS;
        }

        set_fuse_context_uid_gid(pcr);

        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_usermount *pu, void *opc, uint8_t *buf,
        off_t offset, size_t *resid, const struct puffs_cred *pcr,
        int ioflag)
{
        struct puffs_node       *pn = opc;
        struct refusenode       *rn = pn->pn_data;
        struct fuse             *fuse;
        const char              *path = PNPATH(pn);
        int                     ret;

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

        set_fuse_context_uid_gid(pcr);

        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 ((uint64_t)(offset + ret) > pn->pn_va.va_size)
                        pn->pn_va.va_size = offset + ret;
                *resid -= ret;
                ret = (*resid == 0) ? 0 : ENOSPC;
        } else {
                ret = -ret;
        }

        return ret;
}


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

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

        set_fuse_context_uid_gid(pcr);

        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;
        }

        /* Both op.readdir and op.getdir read full directory */
        *eofflag = 1;

        /* now, stuff results into the kernel buffers */
        while (*readoff < (off_t)(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_usermount *pu, void *opc)
{
        struct puffs_node       *pn = opc;

        nukern(pn);
        return 0;
}

/* ARGSUSED1 */
static int
puffs_fuse_fs_unmount(struct puffs_usermount *pu, int flags)
{
        struct fuse             *fuse;

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

/* ARGSUSED0 */
static int
puffs_fuse_fs_sync(struct puffs_usermount *pu, int flags,
            const struct puffs_cred *cr)
{
        set_fuse_context_uid_gid(cr);
        return 0;
}

/* ARGSUSED2 */
static int
puffs_fuse_fs_statvfs(struct puffs_usermount *pu, struct statvfs *svfsb)
{
        struct fuse             *fuse;
        int                     ret;

        fuse = puffs_getspecific(pu);
        if (fuse->op.statfs == NULL) {
                if ((ret = statvfs(PNPATH(puffs_getroot(pu)), svfsb)) == -1) {
                        return errno;
                }
        } else {
                ret = fuse->op.statfs(PNPATH(puffs_getroot(pu)), 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     *fuse;
        char            *mountpoint;
        int              multithreaded;
        int              fd;

        fuse = fuse_setup_real(argc, argv, ops, size, &mountpoint,
            &multithreaded, &fd, userdata);

        return fuse_loop(fuse);
}

/*
 * 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;
        char                     name[64];

        if ((fc = calloc(1, sizeof(*fc))) == NULL) {
                err(EXIT_FAILURE, "fuse_mount");
        }
        fc->dead = 0;

        if ((fc->dir = strdup(dir)) == NULL) {
                err(EXIT_FAILURE, "fuse_mount");
        }

        /*
         * we need to deep copy the args struct - some fuse file
         * systems "clean up" the argument vector for "security
         * reasons"
         */
        fc->args = fuse_opt_deep_copy_args(args->argc, args->argv);

        if (args->argc > 0) {
                set_refuse_mount_name(args->argv, name, sizeof(name));
                if ((args->argv[0] = strdup(name)) == NULL)
                        err(1, "fuse_mount");
        }
        
        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 fuse_context     *fusectx;
        struct puffs_pathobj    *po_root;
        struct puffs_node       *pn_root;
        struct puffs_ops        *pops;
        struct refusenode       *rn_root;
        struct statvfs           svfsb;
        struct stat              st;
        struct fuse             *fuse;
        extern int               puffs_fakecc;
        char                     name[64];
        char                    *argv0;

        if ((fuse = calloc(1, sizeof(*fuse))) == NULL) {
                err(EXIT_FAILURE, "fuse_new");
        }

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

        fusectx = fuse_get_context();
        fusectx->fuse = fuse;
        fusectx->uid = 0;
        fusectx->gid = 0;
        fusectx->pid = 0;
        fusectx->private_data = userdata;

        fuse->fc = fc;

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

        /* 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);

        argv0 = (*args->argv[0] == 0x0) ? fc->args->argv[0] : args->argv[0];
        set_refuse_mount_name(&argv0, name, sizeof(name));

        puffs_fakecc = 1; /* XXX */
        pu = puffs_init(pops, _PATH_PUFFS, name, fuse,
                         PUFFS_FLAG_BUILDPATH
                           | PUFFS_FLAG_HASHPATH
                           | PUFFS_KFLAG_NOCACHE);
        if (pu == NULL) {
                err(EXIT_FAILURE, "puffs_init");
        }
        fc->pu = pu;

        pn_root = newrn(pu);
        puffs_setroot(pu, pn_root);
        rn_root = pn_root->pn_data;
        rn_root->flags |= RN_ROOT;

        po_root = puffs_getrootpathobj(pu);
        if ((po_root->po_path = strdup("/")) == NULL)
                err(1, "fuse_new");
        po_root->po_len = 1;
        puffs_path_buildhash(pu, po_root);

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

        puffs_set_prepost(pu, set_fuse_context_pid, NULL);

        puffs_zerostatvfs(&svfsb);
        if (puffs_mount(pu, fc->dir, MNT_NODEV | MNT_NOSUID, pn_root) == -1) {
                err(EXIT_FAILURE, "puffs_mount: directory \"%s\"", fc->dir);
        }

        return fuse;
}

int
fuse_loop(struct fuse *fuse)
{

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

void
fuse_destroy(struct fuse *fuse)
{

        /*
         * TODO: needs to assert the fs is quiescent, i.e. no other
         * threads exist
         */

        delete_context_key();
        /* XXXXXX: missing stuff */
        free(fuse);
}

void
fuse_exit(struct fuse *fuse)
{
        
        /* XXX: puffs_exit() is WRONG */
        if (fuse->fc->dead == 0)
                puffs_exit(fuse->fc->pu, 1);
        fuse->fc->dead = 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)
{

        /* XXX: puffs_exit() is WRONG */
        if (fc->dead == 0)
                puffs_exit(fc->pu, 1);
        fc->dead = 1;
}

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

        return;
}

/* The next function "exposes" struct fuse to userland.  Not much
* that we can do about this, as we're conforming to a defined
* interface.  */

void
fuse_teardown(struct fuse *fuse, char *mountpoint)
{
        fuse_unmount(mountpoint, fuse->fc);
        fuse_destroy(fuse);
}