lib/fuse.c

/*
    FUSE: Filesystem in Userspace
    Copyright (C) 2001-2005  Miklos Szeredi <miklos@szeredi.hu>

    This program can be distributed under the terms of the GNU LGPL.
    See the file COPYING.LIB
*/

#include "fuse_i.h"
#include "fuse_compat.h"
#include "fuse_kernel.h"
#include "fuse_kernel_compat5.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <assert.h>
#include <stdint.h>
#include <sys/param.h>
#include <sys/uio.h>

/* FUSE flags: */

/** Enable debuging output */
#define FUSE_DEBUG       (1 << 1)

/** If a file is removed but it's still open, don't hide the file but
    remove it immediately */
#define FUSE_HARD_REMOVE (1 << 2)

/** Use st_ino field in getattr instead of generating inode numbers  */
#define FUSE_USE_INO     (1 << 3)

/** Only allow root or the owner to access the filesystem */
#define FUSE_ALLOW_ROOT  (1 << 4)

#define FUSE_KERNEL_MINOR_VERSION_NEED 1
#define FUSE_VERSION_FILE_OLD "/proc/fs/fuse/version"
#define FUSE_VERSION_FILE_NEW "/sys/fs/fuse/version"
#define FUSE_DEV_OLD "/proc/fs/fuse/dev"

#define FUSE_MAX_PATH 4096
#define PARAM_T(inarg, type) (((char *)(inarg)) + sizeof(type))
#define PARAM(inarg) PARAM_T(inarg, *(inarg))
#define PARAM_COMPAT(f, inarg, type) \
    ((f)->major == 5 ? PARAM_T(inarg, struct type ## _compat5) : PARAM(inarg))

#define MEMBER_COMPAT(f, ptr, memb, type) \
    ((f)->major == 5 ? &((struct type ## _compat5 *) (ptr))->memb : &ptr->memb)

#define SIZEOF_COMPAT(f, type) \
    ((f)->major == 5 ? sizeof(struct type ## _compat5) : sizeof(struct type))

#define ENTRY_REVALIDATE_TIME 1 /* sec */
#define ATTR_REVALIDATE_TIME 1 /* sec */


struct node {
    struct node *name_next;
    struct node *id_next;
    nodeid_t nodeid;
    unsigned int generation;
    int refctr;
    nodeid_t parent;
    char *name;
    uint64_t version;
    uint64_t nlookup;
    int open_count;
    int is_hidden;
};

struct fuse_dirhandle {
    pthread_mutex_t lock;
    struct fuse *fuse;
    unsigned char *contents;
    int allocated;
    unsigned len;
    unsigned needlen;
    int filled;
    unsigned long fh;
    int error;
};

struct fuse_cmd {
    char *buf;
    size_t buflen;
};


static struct fuse_context *(*fuse_getcontext)(void) = NULL;

#ifndef USE_UCLIBC
#define mutex_init(mut) pthread_mutex_init(mut, NULL)
#else
static void mutex_init(pthread_mutex_t mut)
{
    pthread_mutexattr_t attr;
    pthread_mutexattr_init(&attr);
    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
    pthread_mutex_init(mut, &attr);
    pthread_mutexattr_destroy(&attr);
}
#endif

static const char *opname(enum fuse_opcode opcode)
{
    switch (opcode) {
    case FUSE_LOOKUP:		return "LOOKUP";
    case FUSE_FORGET:		return "FORGET";
    case FUSE_GETATTR:		return "GETATTR";
    case FUSE_SETATTR:		return "SETATTR";
    case FUSE_READLINK:		return "READLINK";
    case FUSE_SYMLINK:		return "SYMLINK";
    case FUSE_MKNOD:		return "MKNOD";
    case FUSE_MKDIR:		return "MKDIR";
    case FUSE_UNLINK:		return "UNLINK";
    case FUSE_RMDIR:		return "RMDIR";
    case FUSE_RENAME:		return "RENAME";
    case FUSE_LINK:		return "LINK";
    case FUSE_OPEN:		return "OPEN";
    case FUSE_READ:		return "READ";
    case FUSE_WRITE:		return "WRITE";
    case FUSE_STATFS:		return "STATFS";
    case FUSE_FLUSH:		return "FLUSH";
    case FUSE_RELEASE:		return "RELEASE";
    case FUSE_FSYNC:		return "FSYNC";
    case FUSE_SETXATTR:		return "SETXATTR";
    case FUSE_GETXATTR:		return "GETXATTR";
    case FUSE_LISTXATTR:	return "LISTXATTR";
    case FUSE_REMOVEXATTR:	return "REMOVEXATTR";
    case FUSE_INIT:		return "INIT";
    case FUSE_OPENDIR:		return "OPENDIR";
    case FUSE_READDIR:		return "READDIR";
    case FUSE_RELEASEDIR:	return "RELEASEDIR";
    case FUSE_FSYNCDIR:		return "FSYNCDIR";
    default: 			return "???";
    }
}

static inline void fuse_dec_avail(struct fuse *f)
{
    pthread_mutex_lock(&f->worker_lock);
    f->numavail --;
    pthread_mutex_unlock(&f->worker_lock);
}

static inline void fuse_inc_avail(struct fuse *f)
{
    pthread_mutex_lock(&f->worker_lock);
    f->numavail ++;
    pthread_mutex_unlock(&f->worker_lock);
}

static struct node *get_node_nocheck(struct fuse *f, nodeid_t nodeid)
{
    size_t hash = nodeid % f->id_table_size;
    struct node *node;

    for (node = f->id_table[hash]; node != NULL; node = node->id_next)
        if (node->nodeid == nodeid)
            return node;

    return NULL;
}

static struct node *get_node(struct fuse *f, nodeid_t nodeid)
{
    struct node *node = get_node_nocheck(f, nodeid);
    if (!node) {
        fprintf(stderr, "fuse internal error: node %lu not found\n",
                nodeid);
        abort();
    }
    return node;
}

static void free_node(struct node *node)
{
    free(node->name);
    free(node);
}

static void unhash_id(struct fuse *f, struct node *node)
{
    size_t hash = node->nodeid % f->id_table_size;
    struct node **nodep = &f->id_table[hash];

    for (; *nodep != NULL; nodep = &(*nodep)->id_next)
        if (*nodep == node) {
            *nodep = node->id_next;
            return;
        }
}

static void hash_id(struct fuse *f, struct node *node)
{
    size_t hash = node->nodeid % f->id_table_size;
    node->id_next = f->id_table[hash];
    f->id_table[hash] = node;
}

static unsigned int name_hash(struct fuse *f, nodeid_t parent, const char *name)
{
    unsigned int hash = *name;

    if (hash)
        for (name += 1; *name != '\0'; name++)
            hash = (hash << 5) - hash + *name;

    return (hash + parent) % f->name_table_size;
}

static void unref_node(struct fuse *f, struct node *node);

static void unhash_name(struct fuse *f, struct node *node)
{
    if (node->name) {
        size_t hash = name_hash(f, node->parent, node->name);
        struct node **nodep = &f->name_table[hash];

        for (; *nodep != NULL; nodep = &(*nodep)->name_next)
            if (*nodep == node) {
                *nodep = node->name_next;
                node->name_next = NULL;
                unref_node(f, get_node(f, node->parent));
                free(node->name);
                node->name = NULL;
                node->parent = 0;
                return;
            }
        fprintf(stderr, "fuse internal error: unable to unhash node: %lu\n",
                node->nodeid);
        abort();
    }
}

static int hash_name(struct fuse *f, struct node *node, nodeid_t parent,
                     const char *name)
{
    size_t hash = name_hash(f, parent, name);
    node->name = strdup(name);
    if (node->name == NULL)
        return -1;

    get_node(f, parent)->refctr ++;
    node->parent = parent;
    node->name_next = f->name_table[hash];
    f->name_table[hash] = node;
    return 0;
}

static void delete_node(struct fuse *f, struct node *node)
{
    if (f->flags & FUSE_DEBUG) {
        printf("delete: %lu\n", node->nodeid);
        fflush(stdout);
    }
    assert(!node->name);
    unhash_id(f, node);
    free_node(node);
}

static void unref_node(struct fuse *f, struct node *node)
{
    assert(node->refctr > 0);
    node->refctr --;
    if (!node->refctr)
        delete_node(f, node);
}

static nodeid_t next_id(struct fuse *f)
{
    do {
        f->ctr++;
        if (!f->ctr)
            f->generation ++;
    } while (f->ctr == 0 || get_node_nocheck(f, f->ctr) != NULL);
    return f->ctr;
}

static struct node *lookup_node(struct fuse *f, nodeid_t parent,
                                const char *name)
{
    size_t hash = name_hash(f, parent, name);
    struct node *node;

    for (node = f->name_table[hash]; node != NULL; node = node->name_next)
        if (node->parent == parent && strcmp(node->name, name) == 0)
            return node;

    return NULL;
}

static struct node *find_node(struct fuse *f, nodeid_t parent, char *name,
                              struct fuse_attr *attr, uint64_t version)
{
    struct node *node;
    int mode = attr->mode & S_IFMT;
    int rdev = 0;

    if (S_ISCHR(mode) || S_ISBLK(mode))
        rdev = attr->rdev;

    pthread_mutex_lock(&f->lock);
    node = lookup_node(f, parent, name);
    if (node != NULL) {
        if (!(f->flags & FUSE_USE_INO))
            attr->ino = node->nodeid;
    } else {
        node = (struct node *) calloc(1, sizeof(struct node));
        if (node == NULL)
            goto out_err;

        node->refctr = 1;
        node->nodeid = next_id(f);
        if (!(f->flags & FUSE_USE_INO))
            attr->ino = node->nodeid;
        node->open_count = 0;
        node->is_hidden = 0;
        node->generation = f->generation;
        if (hash_name(f, node, parent, name) == -1) {
            free(node);
            node = NULL;
            goto out_err;
        }
        hash_id(f, node);
    }
    node->version = version;
    node->nlookup ++;
 out_err:
    pthread_mutex_unlock(&f->lock);
    return node;
}

static char *add_name(char *buf, char *s, const char *name)
{
    size_t len = strlen(name);
    s -= len;
    if (s <= buf) {
        fprintf(stderr, "fuse: path too long: ...%s\n", s + len);
        return NULL;
    }
    strncpy(s, name, len);
    s--;
    *s = '/';

    return s;
}

static char *get_path_name(struct fuse *f, nodeid_t nodeid, const char *name)
{
    char buf[FUSE_MAX_PATH];
    char *s = buf + FUSE_MAX_PATH - 1;
    struct node *node;

    *s = '\0';

    if (name != NULL) {
        s = add_name(buf, s, name);
        if (s == NULL)
            return NULL;
    }

    pthread_mutex_lock(&f->lock);
    for (node = get_node(f, nodeid); node && node->nodeid != FUSE_ROOT_ID;
         node = get_node(f, node->parent)) {
        if (node->name == NULL) {
            s = NULL;
            break;
        }

        s = add_name(buf, s, node->name);
        if (s == NULL)
            break;
    }
    pthread_mutex_unlock(&f->lock);

    if (node == NULL || s == NULL)
        return NULL;
    else if (*s == '\0')
        return strdup("/");
    else
        return strdup(s);
}

static char *get_path(struct fuse *f, nodeid_t nodeid)
{
    return get_path_name(f, nodeid, NULL);
}

static void forget_node(struct fuse *f, nodeid_t nodeid, uint64_t nlookup)
{
    struct node *node;
    if (nodeid == FUSE_ROOT_ID)
        return;
    pthread_mutex_lock(&f->lock);
    node = get_node(f, nodeid);
    assert(node->nlookup >= nlookup);
    node->nlookup -= nlookup;
    if (!node->nlookup) {
        unhash_name(f, node);
        unref_node(f, node);
    }
    pthread_mutex_unlock(&f->lock);
}

static void forget_node_old(struct fuse *f, nodeid_t nodeid, uint64_t version)
{
    struct node *node;

    pthread_mutex_lock(&f->lock);
    node = get_node_nocheck(f, nodeid);
    if (node && node->version == version && nodeid != FUSE_ROOT_ID) {
        node->version = 0;
        unhash_name(f, node);
        unref_node(f, node);
    }
    pthread_mutex_unlock(&f->lock);
}

static void cancel_lookup(struct fuse *f, nodeid_t nodeid, uint64_t version)
{
    if (f->major <= 6)
        forget_node_old(f, nodeid, version);
    else
        forget_node(f, nodeid, 1);
}

static void remove_node(struct fuse *f, nodeid_t dir, const char *name)
{
    struct node *node;

    pthread_mutex_lock(&f->lock);
    node = lookup_node(f, dir, name);
    if (node != NULL)
        unhash_name(f, node);
    pthread_mutex_unlock(&f->lock);
}

static int rename_node(struct fuse *f, nodeid_t olddir, const char *oldname,
                        nodeid_t newdir, const char *newname, int hide)
{
    struct node *node;
    struct node *newnode;
    int err = 0;

    pthread_mutex_lock(&f->lock);
    node  = lookup_node(f, olddir, oldname);
    newnode  = lookup_node(f, newdir, newname);
    if (node == NULL)
        goto out;

    if (newnode != NULL) {
        if (hide) {
            fprintf(stderr, "fuse: hidden file got created during hiding\n");
            err = -EBUSY;
            goto out;
        }
        unhash_name(f, newnode);
    }

    unhash_name(f, node);
    if (hash_name(f, node, newdir, newname) == -1) {
        err = -ENOMEM;
        goto out;
    }

    if (hide)
        node->is_hidden = 1;

 out:
    pthread_mutex_unlock(&f->lock);
    return err;
}

static void convert_stat(struct stat *stbuf, struct fuse_attr *attr)
{
    attr->ino       = stbuf->st_ino;
    attr->mode      = stbuf->st_mode;
    attr->nlink     = stbuf->st_nlink;
    attr->uid       = stbuf->st_uid;
    attr->gid       = stbuf->st_gid;
    attr->rdev      = stbuf->st_rdev;
    attr->size      = stbuf->st_size;
    attr->blocks    = stbuf->st_blocks;
    attr->atime     = stbuf->st_atime;
    attr->mtime     = stbuf->st_mtime;
    attr->ctime     = stbuf->st_ctime;
#ifdef HAVE_STRUCT_STAT_ST_ATIM
    attr->atimensec = stbuf->st_atim.tv_nsec;
    attr->mtimensec = stbuf->st_mtim.tv_nsec;
    attr->ctimensec = stbuf->st_ctim.tv_nsec;
#endif
}

static  size_t iov_length(const struct iovec *iov, size_t count)
{
    size_t seg;
    size_t ret = 0;

    for (seg = 0; seg < count; seg++)
        ret += iov[seg].iov_len;
    return ret;
}

static int send_reply_raw(struct fuse *f, const struct iovec iov[],
                          size_t count)
{
    int res;
    unsigned outsize = iov_length(iov, count);
    struct fuse_out_header *out = (struct fuse_out_header *) iov[0].iov_base;
    out->len = outsize;

    if ((f->flags & FUSE_DEBUG)) {
        printf("   unique: %llu, error: %i (%s), outsize: %i\n",
               out->unique, out->error, strerror(-out->error), outsize);
        fflush(stdout);
    }

    /* This needs to be done before the reply, otherwise the scheduler
       could play tricks with us, and only let the counter be
       increased long after the operation is done */
    fuse_inc_avail(f);

    res = writev(f->fd, iov, count);
    if (res == -1) {
        /* ENOENT means the operation was interrupted */
        if (!f->exited && errno != ENOENT)
            perror("fuse: writing device");
        return -errno;
    }
    return 0;
}

static int send_reply(struct fuse *f, struct fuse_in_header *in, int error,
                      void *arg, size_t argsize)
{
    struct fuse_out_header out;
    struct iovec iov[2];
    size_t count;

    if (error <= -1000 || error > 0) {
        fprintf(stderr, "fuse: bad error value: %i\n",  error);
        error = -ERANGE;
    }

    out.unique = in->unique;
    out.error = error;
    count = 1;
    iov[0].iov_base = &out;
    iov[0].iov_len = sizeof(struct fuse_out_header);
    if (argsize && !error) {
        count++;
        iov[1].iov_base = arg;
        iov[1].iov_len = argsize;
    }
    return send_reply_raw(f, iov, count);
}

static int is_open(struct fuse *f, nodeid_t dir, const char *name)
{
    struct node *node;
    int isopen = 0;
    pthread_mutex_lock(&f->lock);
    node = lookup_node(f, dir, name);
    if (node && node->open_count > 0)
        isopen = 1;
    pthread_mutex_unlock(&f->lock);
    return isopen;
}

static char *hidden_name(struct fuse *f, nodeid_t dir, const char *oldname,
                        char *newname, size_t bufsize)
{
    struct stat buf;
    struct node *node;
    struct node *newnode;
    char *newpath;
    int res;
    int failctr = 10;

    if (!f->op.getattr)
        return NULL;

    do {
        pthread_mutex_lock(&f->lock);
        node = lookup_node(f, dir, oldname);
        if (node == NULL) {
            pthread_mutex_unlock(&f->lock);
            return NULL;
        }
        do {
            f->hidectr ++;
            snprintf(newname, bufsize, ".fuse_hidden%08x%08x",
                     (unsigned int) node->nodeid, f->hidectr);
            newnode = lookup_node(f, dir, newname);
        } while(newnode);
        pthread_mutex_unlock(&f->lock);

        newpath = get_path_name(f, dir, newname);
        if (!newpath)
            break;

        res = f->op.getattr(newpath, &buf);
        if (res != 0)
            break;
        free(newpath);
        newpath = NULL;
    } while(--failctr);

    return newpath;
}

static int hide_node(struct fuse *f, const char *oldpath, nodeid_t dir,
                     const char *oldname)
{
    char newname[64];
    char *newpath;
    int err = -EBUSY;

    if (f->op.rename && f->op.unlink) {
        newpath = hidden_name(f, dir, oldname, newname, sizeof(newname));
        if (newpath) {
            int res = f->op.rename(oldpath, newpath);
            if (res == 0)
                err = rename_node(f, dir, oldname, dir, newname, 1);
            free(newpath);
        }
    }
    return err;
}

static int lookup_path(struct fuse *f, nodeid_t nodeid, uint64_t version,
                       char *name, const char *path,
                       struct fuse_entry_out *arg)
{
    int res;
    struct stat buf;

    res = f->op.getattr(path, &buf);
    if (res == 0) {
        struct node *node;

        memset(arg, 0, sizeof(struct fuse_entry_out));
        convert_stat(&buf, &arg->attr);
        node = find_node(f, nodeid, name, &arg->attr, version);
        if (node == NULL)
            res = -ENOMEM;
        else {
            arg->nodeid = node->nodeid;
            arg->generation = node->generation;
            arg->entry_valid = ENTRY_REVALIDATE_TIME;
            arg->entry_valid_nsec = 0;
            arg->attr_valid = ATTR_REVALIDATE_TIME;
            arg->attr_valid_nsec = 0;
            if (f->flags & FUSE_DEBUG) {
                printf("   NODEID: %lu\n", (unsigned long) arg->nodeid);
                fflush(stdout);
            }
        }
    }
    return res;
}

static void do_lookup(struct fuse *f, struct fuse_in_header *in, char *name)
{
    int res;
    int res2;
    char *path;
    struct fuse_entry_out arg;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, in->nodeid, name);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("LOOKUP %s\n", path);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.getattr)
            res = lookup_path(f, in->nodeid, in->unique, name, path, &arg);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    res2 = send_reply(f, in, res, &arg, sizeof(arg));
    if (res == 0 && res2 == -ENOENT)
        cancel_lookup(f, arg.nodeid, in->unique);
}

static void do_forget(struct fuse *f, struct fuse_in_header *in,
                      struct fuse_forget_in *arg)
{
    if (f->flags & FUSE_DEBUG) {
        printf("FORGET %lu/%llu\n", (unsigned long) in->nodeid,
               arg->nlookup);
        fflush(stdout);
    }
    if (f->major <= 6)
        forget_node_old(f, in->nodeid, arg->nlookup);
    else
        forget_node(f, in->nodeid, arg->nlookup);
}

static void do_getattr(struct fuse *f, struct fuse_in_header *in)
{
    int res;
    char *path;
    struct stat buf;
    struct fuse_attr_out arg;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.getattr)
            res = f->op.getattr(path, &buf);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    if (res == 0) {
        memset(&arg, 0, sizeof(struct fuse_attr_out));
        arg.attr_valid = ATTR_REVALIDATE_TIME;
        arg.attr_valid_nsec = 0;
        convert_stat(&buf, &arg.attr);
        if (!(f->flags & FUSE_USE_INO))
            arg.attr.ino = in->nodeid;
    }

    send_reply(f, in, res, &arg, sizeof(arg));
}

static int do_chmod(struct fuse *f, const char *path, struct fuse_attr *attr)
{
    int res;

    res = -ENOSYS;
    if (f->op.chmod)
        res = f->op.chmod(path, attr->mode);

    return res;
}

static int do_chown(struct fuse *f, const char *path, struct fuse_attr *attr,
                    int valid)
{
    int res;
    uid_t uid = (valid & FATTR_UID) ? attr->uid : (uid_t) -1;
    gid_t gid = (valid & FATTR_GID) ? attr->gid : (gid_t) -1;

    res = -ENOSYS;
    if (f->op.chown)
        res = f->op.chown(path, uid, gid);

    return res;
}

static int do_truncate(struct fuse *f, const char *path,
                       struct fuse_attr *attr)
{
    int res;

    res = -ENOSYS;
    if (f->op.truncate)
        res = f->op.truncate(path, attr->size);

    return res;
}

static int do_utime(struct fuse *f, const char *path, struct fuse_attr *attr)
{
    int res;
    struct utimbuf buf;
    buf.actime = attr->atime;
    buf.modtime = attr->mtime;
    res = -ENOSYS;
    if (f->op.utime)
        res = f->op.utime(path, &buf);

    return res;
}

static void do_setattr(struct fuse *f, struct fuse_in_header *in,
                       struct fuse_setattr_in *arg)
{
    int res;
    char *path;
    int valid = arg->valid;
    struct fuse_attr *attr = MEMBER_COMPAT(f, arg, attr, fuse_setattr_in);
    struct fuse_attr_out outarg;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.getattr) {
            res = 0;
            if (!res && (valid & FATTR_MODE))
                res = do_chmod(f, path, attr);
            if (!res && (valid & (FATTR_UID | FATTR_GID)))
                res = do_chown(f, path, attr, valid);
            if (!res && (valid & FATTR_SIZE))
                res = do_truncate(f, path, attr);
            if (!res && (valid & (FATTR_ATIME | FATTR_MTIME)) ==
               (FATTR_ATIME | FATTR_MTIME))
                res = do_utime(f, path, attr);
            if (!res) {
                struct stat buf;
                res = f->op.getattr(path, &buf);
                if (!res) {
                    memset(&outarg, 0, sizeof(struct fuse_attr_out));
                    outarg.attr_valid = ATTR_REVALIDATE_TIME;
                    outarg.attr_valid_nsec = 0;
                    convert_stat(&buf, &outarg.attr);
                    if (!(f->flags & FUSE_USE_INO))
                        outarg.attr.ino = in->nodeid;
                }
            }
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, &outarg, sizeof(outarg));
}

static void do_readlink(struct fuse *f, struct fuse_in_header *in)
{
    int res;
    char link[PATH_MAX + 1];
    char *path;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.readlink)
            res = f->op.readlink(path, link, sizeof(link));
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    link[PATH_MAX] = '\0';
    send_reply(f, in, res, link, res == 0 ? strlen(link) : 0);
}

static void do_mknod(struct fuse *f, struct fuse_in_header *in,
                     struct fuse_mknod_in *inarg)
{
    int res;
    int res2;
    char *path;
    char *name = PARAM(inarg);
    struct fuse_entry_out outarg;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, in->nodeid, name);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("MKNOD %s\n", path);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.mknod && f->op.getattr) {
            res = f->op.mknod(path, inarg->mode, inarg->rdev);
            if (res == 0)
                res = lookup_path(f, in->nodeid, in->unique, name, path, &outarg);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    res2 = send_reply(f, in, res, &outarg, sizeof(outarg));
    if (res == 0 && res2 == -ENOENT)
        cancel_lookup(f, outarg.nodeid, in->unique);
}

static void do_mkdir(struct fuse *f, struct fuse_in_header *in,
                     struct fuse_mkdir_in *inarg)
{
    int res;
    int res2;
    char *path;
    char *name = PARAM_COMPAT(f, inarg, fuse_mkdir_in);
    struct fuse_entry_out outarg;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, in->nodeid, name);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("MKDIR %s\n", path);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.mkdir && f->op.getattr) {
            res = f->op.mkdir(path, inarg->mode);
            if (res == 0)
                res = lookup_path(f, in->nodeid, in->unique, name, path, &outarg);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    res2 = send_reply(f, in, res, &outarg, sizeof(outarg));
    if (res == 0 && res2 == -ENOENT)
        cancel_lookup(f, outarg.nodeid, in->unique);
}

static void do_unlink(struct fuse *f, struct fuse_in_header *in, char *name)
{
    int res;
    char *path;

    res = -ENOENT;
    pthread_rwlock_wrlock(&f->tree_lock);
    path = get_path_name(f, in->nodeid, name);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("UNLINK %s\n", path);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.unlink) {
            if (!(f->flags & FUSE_HARD_REMOVE) && is_open(f, in->nodeid, name))
                res = hide_node(f, path, in->nodeid, name);
            else {
                res = f->op.unlink(path);
                if (res == 0)
                    remove_node(f, in->nodeid, name);

            }
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static void do_rmdir(struct fuse *f, struct fuse_in_header *in, char *name)
{
    int res;
    char *path;

    res = -ENOENT;
    pthread_rwlock_wrlock(&f->tree_lock);
    path = get_path_name(f, in->nodeid, name);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("RMDIR %s\n", path);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.rmdir) {
            res = f->op.rmdir(path);
            if (res == 0)
                remove_node(f, in->nodeid, name);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static void do_symlink(struct fuse *f, struct fuse_in_header *in, char *name,
                       char *link)
{
    int res;
    int res2;
    char *path;
    struct fuse_entry_out outarg;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, in->nodeid, name);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("SYMLINK %s\n", path);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.symlink && f->op.getattr) {
            res = f->op.symlink(link, path);
            if (res == 0)
                res = lookup_path(f, in->nodeid, in->unique, name, path, &outarg);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    res2 = send_reply(f, in, res, &outarg, sizeof(outarg));
    if (res == 0 && res2 == -ENOENT)
        cancel_lookup(f, outarg.nodeid, in->unique);

}

static void do_rename(struct fuse *f, struct fuse_in_header *in,
                      struct fuse_rename_in *inarg)
{
    int res;
    nodeid_t olddir = in->nodeid;
    nodeid_t newdir = inarg->newdir;
    char *oldname = PARAM(inarg);
    char *newname = oldname + strlen(oldname) + 1;
    char *oldpath;
    char *newpath;

    res = -ENOENT;
    pthread_rwlock_wrlock(&f->tree_lock);
    oldpath = get_path_name(f, olddir, oldname);
    if (oldpath != NULL) {
        newpath = get_path_name(f, newdir, newname);
        if (newpath != NULL) {
            if (f->flags & FUSE_DEBUG) {
                printf("RENAME %s -> %s\n", oldpath, newpath);
                fflush(stdout);
            }
            res = -ENOSYS;
            if (f->op.rename) {
                res = 0;
                if (!(f->flags & FUSE_HARD_REMOVE) &&
                    is_open(f, newdir, newname))
                    res = hide_node(f, newpath, newdir, newname);
                if (res == 0) {
                    res = f->op.rename(oldpath, newpath);
                    if (res == 0)
                        res = rename_node(f, olddir, oldname, newdir, newname, 0);
                }
            }
            free(newpath);
        }
        free(oldpath);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static void do_link(struct fuse *f, struct fuse_in_header *in,
                    struct fuse_link_in *arg)
{
    int res;
    int res2;
    char *oldpath;
    char *newpath;
    char *name = PARAM(arg);
    struct fuse_entry_out outarg;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    oldpath = get_path(f, arg->oldnodeid);
    if (oldpath != NULL) {
        newpath =  get_path_name(f, in->nodeid, name);
        if (newpath != NULL) {
            if (f->flags & FUSE_DEBUG) {
                printf("LINK %s\n", newpath);
                fflush(stdout);
            }
            res = -ENOSYS;
            if (f->op.link && f->op.getattr) {
                res = f->op.link(oldpath, newpath);
                if (res == 0)
                    res = lookup_path(f, in->nodeid, in->unique, name,
                                      newpath, &outarg);
            }
            free(newpath);
        }
        free(oldpath);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    res2 = send_reply(f, in, res, &outarg, sizeof(outarg));
    if (res == 0 && res2 == -ENOENT)
        cancel_lookup(f, outarg.nodeid, in->unique);
}

static void do_open(struct fuse *f, struct fuse_in_header *in,
                    struct fuse_open_in *arg)
{
    int res;
    char *path;
    struct fuse_open_out outarg;
    struct fuse_file_info fi;

    memset(&outarg, 0, sizeof(outarg));
    memset(&fi, 0, sizeof(fi));
    fi.flags = arg->flags;
    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.open) {
            if (!f->compat)
                res = f->op.open(path, &fi);
            else
                res = ((struct fuse_operations_compat2 *) &f->op)->open(path, fi.flags);
        }
    }
    if (res == 0) {
        int res2;
        outarg.fh = fi.fh;
        if (f->flags & FUSE_DEBUG) {
            printf("OPEN[%lu] flags: 0x%x\n", fi.fh, arg->flags);
            fflush(stdout);
        }

        pthread_mutex_lock(&f->lock);
        res2 = send_reply(f, in, res, &outarg, SIZEOF_COMPAT(f, fuse_open_out));
        if(res2 == -ENOENT) {
            /* The open syscall was interrupted, so it must be cancelled */
            if(f->op.release) {
                if (!f->compat)
                    f->op.release(path, &fi);
                else
                    ((struct fuse_operations_compat2 *) &f->op)->release(path, fi.flags);
            }
        } else {
            struct node *node = get_node(f, in->nodeid);
            node->open_count ++;
        }
        pthread_mutex_unlock(&f->lock);
    } else
        send_reply(f, in, res, NULL, 0);

    if (path)
        free(path);
    pthread_rwlock_unlock(&f->tree_lock);
}

static void do_flush(struct fuse *f, struct fuse_in_header *in,
                     struct fuse_flush_in *arg)
{
    char *path;
    int res;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("FLUSH[%lu]\n", (unsigned long) arg->fh);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.flush)
            res = f->op.flush(path, &fi);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static void do_release(struct fuse *f, struct fuse_in_header *in,
                       struct fuse_release_in *arg)
{
    struct node *node;
    char *path;
    struct fuse_file_info fi;
    int unlink_hidden;

    memset(&fi, 0, sizeof(fi));
    fi.flags = arg->flags;
    fi.fh = arg->fh;

    pthread_mutex_lock(&f->lock);
    node = get_node(f, in->nodeid);
    assert(node->open_count > 0);
    --node->open_count;
    unlink_hidden = (node->is_hidden && !node->open_count);
    pthread_mutex_unlock(&f->lock);

    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (f->flags & FUSE_DEBUG) {
        printf("RELEASE[%lu] flags: 0x%x\n", fi.fh, fi.flags);
        fflush(stdout);
    }
    if (f->op.release) {
        if (!f->compat)
            f->op.release(path ? path : "-", &fi);
        else if (path)
            ((struct fuse_operations_compat2 *) &f->op)->release(path, fi.flags);
    }

    if(unlink_hidden && path)
        f->op.unlink(path);

    if (path)
        free(path);
    pthread_rwlock_unlock(&f->tree_lock);

    send_reply(f, in, 0, NULL, 0);
}

static void do_read(struct fuse *f, struct fuse_in_header *in,
                    struct fuse_read_in *arg)
{
    int res;
    char *path;
    size_t size;
    char *buf;
    struct fuse_file_info fi;

    buf = (char *) malloc(arg->size);
    if (buf == NULL) {
        send_reply(f, in, -ENOMEM, NULL, 0);
        return;
    }

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("READ[%lu] %u bytes from %llu\n",
                   (unsigned long) arg->fh, arg->size, arg->offset);
            fflush(stdout);
        }

        res = -ENOSYS;
        if (f->op.read)
            res = f->op.read(path, buf, arg->size, arg->offset, &fi);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    size = 0;
    if (res >= 0) {
        size = res;
        res = 0;
        if (f->flags & FUSE_DEBUG) {
            printf("   READ[%lu] %u bytes\n", (unsigned long) arg->fh,
                   size);
            fflush(stdout);
        }
    }

    send_reply(f, in, res, buf, size);
    free(buf);
}

static void do_write(struct fuse *f, struct fuse_in_header *in,
                     struct fuse_write_in *arg)
{
    int res;
    char *path;
    struct fuse_write_out outarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.writepage = arg->write_flags & 1;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("WRITE%s[%lu] %u bytes to %llu\n",
                   (arg->write_flags & 1) ? "PAGE" : "",
                   (unsigned long) arg->fh, arg->size, arg->offset);
            fflush(stdout);
        }

        res = -ENOSYS;
        if (f->op.write)
            res = f->op.write(path, PARAM(arg), arg->size, arg->offset, &fi);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    memset(&outarg, 0, sizeof(outarg));
    if (res >= 0) {
        outarg.size = res;
        res = 0;
    }

    send_reply(f, in, res, &outarg, SIZEOF_COMPAT(f, fuse_write_out));
}

static int default_statfs(struct statfs *buf)
{
    buf->f_namelen = 255;
    buf->f_bsize = 512;
    return 0;
}

static void convert_statfs_compat(struct fuse_statfs_compat1 *compatbuf,
                                  struct statfs *statfs)
{
    statfs->f_bsize   = compatbuf->block_size;
    statfs->f_blocks  = compatbuf->blocks;
    statfs->f_bfree   = compatbuf->blocks_free;
    statfs->f_bavail  = compatbuf->blocks_free;
    statfs->f_files   = compatbuf->files;
    statfs->f_ffree   = compatbuf->files_free;
    statfs->f_namelen = compatbuf->namelen;
}

static void convert_statfs(struct statfs *statfs, struct fuse_kstatfs *kstatfs)
{
    kstatfs->bsize	= statfs->f_bsize;
    kstatfs->blocks	= statfs->f_blocks;
    kstatfs->bfree	= statfs->f_bfree;
    kstatfs->bavail	= statfs->f_bavail;
    kstatfs->files	= statfs->f_files;
    kstatfs->ffree	= statfs->f_ffree;
    kstatfs->namelen	= statfs->f_namelen;
}

static void do_statfs(struct fuse *f, struct fuse_in_header *in)
{
    int res;
    struct fuse_statfs_out arg;
    struct statfs buf;

    memset(&buf, 0, sizeof(struct statfs));
    if (f->op.statfs) {
        if (!f->compat || f->compat > 11)
            res = f->op.statfs("/", &buf);
        else {
            struct fuse_statfs_compat1 compatbuf;
            memset(&compatbuf, 0, sizeof(struct fuse_statfs_compat1));
            res = ((struct fuse_operations_compat1 *) &f->op)->statfs(&compatbuf);
            if (res == 0)
                convert_statfs_compat(&compatbuf, &buf);
        }
    }
    else
        res = default_statfs(&buf);

    if (res == 0)
        convert_statfs(&buf, &arg.st);

    send_reply(f, in, res, &arg, sizeof(arg));
}

static void do_fsync(struct fuse *f, struct fuse_in_header *in,
                     struct fuse_fsync_in *inarg)
{
    int res;
    char *path;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = inarg->fh;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        if (f->flags & FUSE_DEBUG) {
            printf("FSYNC[%lu]\n", (unsigned long) inarg->fh);
            fflush(stdout);
        }
        res = -ENOSYS;
        if (f->op.fsync)
            res = f->op.fsync(path, inarg->fsync_flags & 1, &fi);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static void do_setxattr(struct fuse *f, struct fuse_in_header *in,
                        struct fuse_setxattr_in *arg)
{
    int res;
    char *path;
    char *name = PARAM(arg);
    unsigned char *value = name + strlen(name) + 1;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.setxattr)
            res = f->op.setxattr(path, name, value, arg->size, arg->flags);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static int common_getxattr(struct fuse *f, struct fuse_in_header *in,
                           const char *name, char *value, size_t size)
{
    int res;
    char *path;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.getxattr)
            res = f->op.getxattr(path, name, value, size);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    return res;
}

static void do_getxattr_read(struct fuse *f, struct fuse_in_header *in,
                             const char *name, size_t size)
{
    int res;
    char *value = (char *) malloc(size);
    if (value == NULL) {
        send_reply(f, in, -ENOMEM, NULL, 0);
        return;
    }
    res = common_getxattr(f, in, name, value, size);
    size = 0;
    if (res > 0) {
        size = res;
        res = 0;
    }
    send_reply(f, in, res, value, size);
    free(value);
}

static void do_getxattr_size(struct fuse *f, struct fuse_in_header *in,
                             const char *name)
{
    int res;
    struct fuse_getxattr_out arg;

    memset(&arg, 0, sizeof(arg));
    res = common_getxattr(f, in, name, NULL, 0);
    if (res >= 0) {
        arg.size = res;
        res = 0;
    }
    send_reply(f, in, res, &arg, SIZEOF_COMPAT(f, fuse_getxattr_out));
}

static void do_getxattr(struct fuse *f, struct fuse_in_header *in,
                        struct fuse_getxattr_in *arg)
{
    char *name = PARAM(arg);

    if (arg->size)
        do_getxattr_read(f, in, name, arg->size);
    else
        do_getxattr_size(f, in, name);
}

static int common_listxattr(struct fuse *f, struct fuse_in_header *in,
                            char *list, size_t size)
{
    int res;
    char *path;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.listxattr)
            res = f->op.listxattr(path, list, size);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    return res;
}

static void do_listxattr_read(struct fuse *f, struct fuse_in_header *in,
                              size_t size)
{
    int res;
    char *list = (char *) malloc(size);
    if (list == NULL) {
        send_reply(f, in, -ENOMEM, NULL, 0);
        return;
    }
    res = common_listxattr(f, in, list, size);
    size = 0;
    if (res > 0) {
        size = res;
        res = 0;
    }
    send_reply(f, in, res, list, size);
    free(list);
}

static void do_listxattr_size(struct fuse *f, struct fuse_in_header *in)
{
    int res;
    struct fuse_getxattr_out arg;

    memset(&arg, 0, sizeof(arg));
    res = common_listxattr(f, in, NULL, 0);
    if (res >= 0) {
        arg.size = res;
        res = 0;
    }
    send_reply(f, in, res, &arg, SIZEOF_COMPAT(f, fuse_getxattr_out));
}

static void do_listxattr(struct fuse *f, struct fuse_in_header *in,
                         struct fuse_getxattr_in *arg)
{
    if (arg->size)
        do_listxattr_read(f, in, arg->size);
    else
        do_listxattr_size(f, in);
}

static void do_removexattr(struct fuse *f, struct fuse_in_header *in,
                           char *name)
{
    int res;
    char *path;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.removexattr)
            res = f->op.removexattr(path, name);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static void do_init(struct fuse *f, struct fuse_in_header *in,
                    struct fuse_init_in_out *arg)
{
    struct fuse_init_in_out outarg;

    if (in->padding == 5) {
        arg->minor = arg->major;
        arg->major = in->padding;
    }

    if (f->flags & FUSE_DEBUG) {
        printf("INIT: %u.%u\n", arg->major, arg->minor);
        fflush(stdout);
    }
    f->got_init = 1;
    if (f->op.init)
        f->user_data = f->op.init();

    if (arg->major == 5) {
        f->major = 5;
        f->minor = 1;
    } else if (arg->major == 6) {
        f->major = 6;
        f->minor = 1;
    } else {
        f->major = FUSE_KERNEL_VERSION;
        f->minor = FUSE_KERNEL_MINOR_VERSION;
    }
    memset(&outarg, 0, sizeof(outarg));
    outarg.major = f->major;
    outarg.minor = f->minor;

    if (f->flags & FUSE_DEBUG) {
        printf("   INIT: %u.%u\n", outarg.major, outarg.minor);
        fflush(stdout);
    }

    send_reply(f, in, 0, &outarg, sizeof(outarg));
}

static struct fuse_dirhandle *get_dirhandle(unsigned long fh)
{
    return (struct fuse_dirhandle *) fh;
}

static void do_opendir(struct fuse *f, struct fuse_in_header *in,
                       struct fuse_open_in *arg)
{
    int res;
    struct fuse_open_out outarg;
    struct fuse_dirhandle *dh;

    dh = (struct fuse_dirhandle *) malloc(sizeof(struct fuse_dirhandle));
    if (dh == NULL) {
        send_reply(f, in, -ENOMEM, NULL, 0);
        return;
    }
    memset(dh, 0, sizeof(struct fuse_dirhandle));
    dh->fuse = f;
    dh->contents = NULL;
    dh->len = 0;
    dh->filled = 0;
    mutex_init(&dh->lock);

    memset(&outarg, 0, sizeof(outarg));
    outarg.fh = (unsigned long) dh;

    if (f->op.opendir) {
        struct fuse_file_info fi;
        char *path;

        memset(&fi, 0, sizeof(fi));
        fi.flags = arg->flags;

        res = -ENOENT;
        pthread_rwlock_rdlock(&f->tree_lock);
        path = get_path(f, in->nodeid);
        if (path != NULL) {
            res = f->op.opendir(path, &fi);
            dh->fh = fi.fh;
        }
        if (res == 0) {
            int res2;
            pthread_mutex_lock(&f->lock);
            res2 = send_reply(f, in, res, &outarg, SIZEOF_COMPAT(f, fuse_open_out));
            if(res2 == -ENOENT) {
                /* The opendir syscall was interrupted, so it must be
                   cancelled */
                if(f->op.releasedir)
                    f->op.releasedir(path, &fi);
                pthread_mutex_destroy(&dh->lock);
                free(dh);
            }
            pthread_mutex_unlock(&f->lock);
        } else {
            send_reply(f, in, res, NULL, 0);
            free(dh);
        }
        free(path);
        pthread_rwlock_unlock(&f->tree_lock);
    } else
        send_reply(f, in, 0, &outarg, SIZEOF_COMPAT(f, fuse_open_out));
}

static int fill_dir_common(struct fuse_dirhandle *dh, const char *name,
                           int type, ino_t ino, off_t off)
{
    unsigned namelen = strlen(name);
    unsigned entlen;
    unsigned entsize;
    unsigned padlen;
    unsigned newlen;
    unsigned char *newptr;

    if (!(dh->fuse->flags & FUSE_USE_INO))
        ino = (ino_t) -1;

    if (namelen > FUSE_NAME_MAX)
        namelen = FUSE_NAME_MAX;
    else if (!namelen) {
        dh->error = -EIO;
        return 1;
    }

    entlen = (dh->fuse->major == 5 ?
              FUSE_NAME_OFFSET_COMPAT5 : FUSE_NAME_OFFSET) + namelen;
    entsize = FUSE_DIRENT_ALIGN(entlen);
    padlen = entsize - entlen;
    newlen = dh->len + entsize;
    if (off && dh->fuse->major != 5) {
        dh->filled = 0;
        if (newlen > dh->needlen)
            return 1;
    }

    newptr = realloc(dh->contents, newlen);
    if (!newptr) {
        dh->error = -ENOMEM;
        return 1;
    }
    dh->contents = newptr;
    if (dh->fuse->major == 5) {
        struct fuse_dirent_compat5 *dirent;
        dirent = (struct fuse_dirent_compat5 *) (dh->contents + dh->len);
        dirent->ino = ino;
        dirent->namelen = namelen;
        dirent->type = type;
        strncpy(dirent->name, name, namelen);
    } else {
        struct fuse_dirent *dirent;
        dirent = (struct fuse_dirent *) (dh->contents + dh->len);
        dirent->ino = ino;
        dirent->off = off ? off : newlen;
        dirent->namelen = namelen;
        dirent->type = type;
        strncpy(dirent->name, name, namelen);
    }
    if (padlen)
        memset(dh->contents + dh->len + entlen, 0, padlen);
    dh->len = newlen;
    return 0;
}

static int fill_dir(void *buf, const char *name, const struct stat *stat,
                    off_t off)
{
    int type = stat ? (stat->st_mode & 0170000) >> 12 : 0;
    ino_t ino = stat ? stat->st_ino : (ino_t) -1;
    return fill_dir_common(buf, name, type, ino, off);
}

static int fill_dir_old(struct fuse_dirhandle *dh, const char *name, int type,
                        ino_t ino)
{
    fill_dir_common(dh, name, type, ino, 0);
    return dh->error;
}

static int readdir_fill(struct fuse *f, struct fuse_in_header *in,
                        struct fuse_read_in *arg, struct fuse_dirhandle *dh)
{
    int err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    char *path = get_path(f, in->nodeid);
    if (path != NULL) {
        struct fuse_file_info fi;

        memset(&fi, 0, sizeof(fi));
        fi.fh = dh->fh;

        dh->len = 0;
        dh->error = 0;
        dh->needlen = arg->size;
        dh->filled = 1;
        err = -ENOSYS;
        if (f->op.readdir) {
            off_t offset = f->major == 5 ? 0 : arg->offset;
            err = f->op.readdir(path, dh, fill_dir, offset, &fi);
        } else if (f->op.getdir)
            err = f->op.getdir(path, dh, fill_dir_old);
        if (!err)
            err = dh->error;
        if (err)
            dh->filled = 0;
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    return err;
}

static void do_readdir(struct fuse *f, struct fuse_in_header *in,
                       struct fuse_read_in *arg)
{
    int err = 0;
    struct fuse_dirhandle *dh = get_dirhandle(arg->fh);
    size_t size = 0;
    unsigned char *buf = NULL;

    pthread_mutex_lock(&dh->lock);
    if (!dh->filled) {
        err = readdir_fill(f, in, arg, dh);
        if (err)
            goto out;
    }
    if (dh->filled) {
        if (arg->offset < dh->len) {
            size = arg->size;
            if (arg->offset + size > dh->len)
                size = dh->len - arg->offset;
            buf = dh->contents + arg->offset;
        }
    } else {
        size = dh->len;
        buf = dh->contents;
    }

 out:
    send_reply(f, in, err, buf, size);
    pthread_mutex_unlock(&dh->lock);
}

static void do_releasedir(struct fuse *f, struct fuse_in_header *in,
                          struct fuse_release_in *arg)
{
    struct fuse_dirhandle *dh = get_dirhandle(arg->fh);
    if (f->op.releasedir) {
        char *path;
        struct fuse_file_info fi;

        memset(&fi, 0, sizeof(fi));
        fi.fh = dh->fh;

        pthread_rwlock_rdlock(&f->tree_lock);
        path = get_path(f, in->nodeid);
        f->op.releasedir(path ? path : "-", &fi);
        free(path);
        pthread_rwlock_unlock(&f->tree_lock);
    }
    pthread_mutex_lock(&dh->lock);
    pthread_mutex_unlock(&dh->lock);
    pthread_mutex_destroy(&dh->lock);
    free(dh->contents);
    free(dh);
    send_reply(f, in, 0, NULL, 0);
}

static void do_fsyncdir(struct fuse *f, struct fuse_in_header *in,
                        struct fuse_fsync_in *inarg)
{
    int res;
    char *path;
    struct fuse_dirhandle *dh = get_dirhandle(inarg->fh);
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = dh->fh;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, in->nodeid);
    if (path != NULL) {
        res = -ENOSYS;
        if (f->op.fsyncdir)
            res = f->op.fsyncdir(path, inarg->fsync_flags & 1, &fi);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    send_reply(f, in, res, NULL, 0);
}

static void free_cmd(struct fuse_cmd *cmd)
{
    free(cmd->buf);
    free(cmd);
}

void fuse_process_cmd(struct fuse *f, struct fuse_cmd *cmd)
{
    struct fuse_in_header *in = (struct fuse_in_header *) cmd->buf;
    void *inarg = cmd->buf + SIZEOF_COMPAT(f, fuse_in_header);
    struct fuse_context *ctx = fuse_get_context();

    fuse_dec_avail(f);

    if ((f->flags & FUSE_DEBUG)) {
        printf("unique: %llu, opcode: %s (%i), nodeid: %lu, insize: %i\n",
               in->unique, opname(in->opcode), in->opcode,
               (unsigned long) in->nodeid, cmd->buflen);
        fflush(stdout);
    }

    if (!f->got_init && in->opcode != FUSE_INIT) {
        /* Old kernel version probably */
        send_reply(f, in, -EPROTO, NULL, 0);
        goto out;
    }

    if ((f->flags & FUSE_ALLOW_ROOT) && in->uid != f->owner && in->uid != 0 &&
        in->opcode != FUSE_INIT && in->opcode != FUSE_READ &&
        in->opcode != FUSE_WRITE && in->opcode != FUSE_FSYNC &&
        in->opcode != FUSE_RELEASE && in->opcode != FUSE_READDIR &&
        in->opcode != FUSE_FSYNCDIR && in->opcode != FUSE_RELEASEDIR) {
        send_reply(f, in, -EACCES, NULL, 0);
        goto out;
    }

    ctx->fuse = f;
    ctx->uid = in->uid;
    ctx->gid = in->gid;
    ctx->pid = in->pid;
    ctx->private_data = f->user_data;

    switch (in->opcode) {
    case FUSE_LOOKUP:
        do_lookup(f, in, (char *) inarg);
        break;

    case FUSE_GETATTR:
        do_getattr(f, in);
        break;

    case FUSE_SETATTR:
        do_setattr(f, in, (struct fuse_setattr_in *) inarg);
        break;

    case FUSE_READLINK:
        do_readlink(f, in);
        break;

    case FUSE_MKNOD:
        do_mknod(f, in, (struct fuse_mknod_in *) inarg);
        break;

    case FUSE_MKDIR:
        do_mkdir(f, in, (struct fuse_mkdir_in *) inarg);
        break;

    case FUSE_UNLINK:
        do_unlink(f, in, (char *) inarg);
        break;

    case FUSE_RMDIR:
        do_rmdir(f, in, (char *) inarg);
        break;

    case FUSE_SYMLINK:
        do_symlink(f, in, (char *) inarg,
                   ((char *) inarg) + strlen((char *) inarg) + 1);
        break;

    case FUSE_RENAME:
        do_rename(f, in, (struct fuse_rename_in *) inarg);
        break;

    case FUSE_LINK:
        do_link(f, in, (struct fuse_link_in *) inarg);
        break;

    case FUSE_OPEN:
        do_open(f, in, (struct fuse_open_in *) inarg);
        break;

    case FUSE_FLUSH:
        do_flush(f, in, (struct fuse_flush_in *) inarg);
        break;

    case FUSE_RELEASE:
        do_release(f, in, (struct fuse_release_in *) inarg);
        break;

    case FUSE_READ:
        do_read(f, in, (struct fuse_read_in *) inarg);
        break;

    case FUSE_WRITE:
        do_write(f, in, (struct fuse_write_in *) inarg);
        break;

    case FUSE_STATFS:
        do_statfs(f, in);
        break;

    case FUSE_FSYNC:
        do_fsync(f, in, (struct fuse_fsync_in *) inarg);
        break;

    case FUSE_SETXATTR:
        do_setxattr(f, in, (struct fuse_setxattr_in *) inarg);
        break;

    case FUSE_GETXATTR:
        do_getxattr(f, in, (struct fuse_getxattr_in *) inarg);
        break;

    case FUSE_LISTXATTR:
        do_listxattr(f, in, (struct fuse_getxattr_in *) inarg);
        break;

    case FUSE_REMOVEXATTR:
        do_removexattr(f, in, (char *) inarg);
        break;

    case FUSE_INIT:
        do_init(f, in, (struct fuse_init_in_out *) inarg);
        break;

    case FUSE_OPENDIR:
        do_opendir(f, in, (struct fuse_open_in *) inarg);
        break;

    case FUSE_READDIR:
        do_readdir(f, in, (struct fuse_read_in *) inarg);
        break;

    case FUSE_RELEASEDIR:
        do_releasedir(f, in, (struct fuse_release_in *) inarg);
        break;

    case FUSE_FSYNCDIR:
        do_fsyncdir(f, in, (struct fuse_fsync_in *) inarg);
        break;

    default:
        send_reply(f, in, -ENOSYS, NULL, 0);
    }

 out:
    free_cmd(cmd);
}

int fuse_exited(struct fuse* f)
{
    return f->exited;
}

struct fuse_cmd *fuse_read_cmd(struct fuse *f)
{
    ssize_t res;
    struct fuse_cmd *cmd;
    struct fuse_in_header *in;
    void *inarg;

    cmd = (struct fuse_cmd *) malloc(sizeof(struct fuse_cmd));
    if (cmd == NULL) {
        fprintf(stderr, "fuse: failed to allocate cmd in read\n");
        return NULL;
    }
    cmd->buf = (char *) malloc(FUSE_MAX_IN);
    if (cmd->buf == NULL) {
        fprintf(stderr, "fuse: failed to allocate read buffer\n");
        free(cmd);
        return NULL;
    }
    in = (struct fuse_in_header *) cmd->buf;
    inarg = cmd->buf + SIZEOF_COMPAT(f, fuse_in_header);

    res = read(f->fd, cmd->buf, FUSE_MAX_IN);
    if (res == -1) {
        free_cmd(cmd);
        if (fuse_exited(f) || errno == EINTR || errno == ENOENT)
            return NULL;

        /* ENODEV means we got unmounted, so we silenty return failure */
        if (errno != ENODEV) {
            /* BAD... This will happen again */
            perror("fuse: reading device");
        }

        fuse_exit(f);
        return NULL;
    }
    if ((size_t) res < SIZEOF_COMPAT(f, fuse_in_header)) {
        free_cmd(cmd);
        /* Cannot happen */
        fprintf(stderr, "short read on fuse device\n");
        fuse_exit(f);
        return NULL;
    }
    cmd->buflen = res;

    /* Forget is special, it can be done without messing with threads. */
    if (in->opcode == FUSE_FORGET) {
        do_forget(f, in, (struct fuse_forget_in *) inarg);
        free_cmd(cmd);
        return NULL;
    }

    return cmd;
}

int fuse_loop(struct fuse *f)
{
    if (f == NULL)
        return -1;

    while (1) {
        struct fuse_cmd *cmd;

        if (fuse_exited(f))
            break;

        cmd = fuse_read_cmd(f);
        if (cmd == NULL)
            continue;

        fuse_process_cmd(f, cmd);
    }
    f->exited = 0;
    return 0;
}

int fuse_invalidate(struct fuse *f, const char *path)
{
    (void) f;
    (void) path;
    return -EINVAL;
}

void fuse_exit(struct fuse *f)
{
    f->exited = 1;
}

struct fuse_context *fuse_get_context()
{
    static struct fuse_context context;
    if (fuse_getcontext)
        return fuse_getcontext();
    else
        return &context;
}

void fuse_set_getcontext_func(struct fuse_context *(*func)(void))
{
    fuse_getcontext = func;
}

int fuse_is_lib_option(const char *opt)
{
    if (strcmp(opt, "debug") == 0 ||
        strcmp(opt, "hard_remove") == 0 ||
        strcmp(opt, "use_ino") == 0 ||
        strcmp(opt, "allow_root") == 0)
        return 1;
    else
        return 0;
}

static int parse_lib_opts(struct fuse *f, const char *opts)
{
    if (opts) {
        char *xopts = strdup(opts);
        char *s = xopts;
        char *opt;

        if (xopts == NULL) {
            fprintf(stderr, "fuse: memory allocation failed\n");
            return -1;
        }

        while((opt = strsep(&s, ","))) {
            if (strcmp(opt, "debug") == 0)
                f->flags |= FUSE_DEBUG;
            else if (strcmp(opt, "hard_remove") == 0)
                f->flags |= FUSE_HARD_REMOVE;
            else if (strcmp(opt, "use_ino") == 0)
                f->flags |= FUSE_USE_INO;
            else if (strcmp(opt, "allow_root") == 0)
                f->flags |= FUSE_ALLOW_ROOT;
            else
                fprintf(stderr, "fuse: warning: unknown option `%s'\n", opt);
        }
        free(xopts);
    }
    return 0;
}

struct fuse *fuse_new_common(int fd, const char *opts,
                             const struct fuse_operations *op,
                             size_t op_size, int compat)
{
    struct fuse *f;
    struct node *root;

    if (sizeof(struct fuse_operations) < op_size) {
        fprintf(stderr, "fuse: warning: library too old, some operations may not not work\n");
        op_size = sizeof(struct fuse_operations);
    }

    f = (struct fuse *) calloc(1, sizeof(struct fuse));
    if (f == NULL) {
        fprintf(stderr, "fuse: failed to allocate fuse object\n");
        goto out;
    }

    if (parse_lib_opts(f, opts) == -1)
        goto out_free;

    f->fd = fd;
    f->ctr = 0;
    f->generation = 0;
    /* FIXME: Dynamic hash table */
    f->name_table_size = 14057;
    f->name_table = (struct node **)
        calloc(1, sizeof(struct node *) * f->name_table_size);
    if (f->name_table == NULL) {
        fprintf(stderr, "fuse: memory allocation failed\n");
        goto out_free;
    }

    f->id_table_size = 14057;
    f->id_table = (struct node **)
        calloc(1, sizeof(struct node *) * f->id_table_size);
    if (f->id_table == NULL) {
        fprintf(stderr, "fuse: memory allocation failed\n");
        goto out_free_name_table;
    }

    mutex_init(&f->lock);
    mutex_init(&f->worker_lock);
    f->numworker = 0;
    f->numavail = 0;
    memcpy(&f->op, op, op_size);
    f->compat = compat;
    f->exited = 0;

    root = (struct node *) calloc(1, sizeof(struct node));
    if (root == NULL) {
        fprintf(stderr, "fuse: memory allocation failed\n");
        goto out_free_id_table;
    }

    root->name = strdup("/");
    if (root->name == NULL) {
        fprintf(stderr, "fuse: memory allocation failed\n");
        goto out_free_root;
    }

    root->parent = 0;
    root->nodeid = FUSE_ROOT_ID;
    root->generation = 0;
    root->refctr = 1;
    root->nlookup = 1;
    hash_id(f, root);

    f->owner = getuid();

    return f;

 out_free_root:
    free(root);
 out_free_id_table:
    free(f->id_table);
 out_free_name_table:
    free(f->name_table);
 out_free:
    free(f);
 out:
    return NULL;
}

struct fuse *fuse_new(int fd, const char *opts,
                      const struct fuse_operations *op, size_t op_size)
{
    return fuse_new_common(fd, opts, op, op_size, 0);
}

struct fuse *fuse_new_compat2(int fd, const char *opts,
                              const struct fuse_operations_compat2 *op)
{
    return fuse_new_common(fd, opts, (struct fuse_operations *) op,
                           sizeof(struct fuse_operations_compat2), 21);
}

struct fuse *fuse_new_compat1(int fd, int flags,
                              const struct fuse_operations_compat1 *op)
{
    char *opts = NULL;
    if (flags & FUSE_DEBUG_COMPAT1)
        opts = "debug";
    return fuse_new_common(fd, opts, (struct fuse_operations *) op,
                           sizeof(struct fuse_operations_compat1), 11);
}

void fuse_destroy(struct fuse *f)
{
    size_t i;
    for (i = 0; i < f->id_table_size; i++) {
        struct node *node;

        for (node = f->id_table[i]; node != NULL; node = node->id_next) {
            if (node->is_hidden) {
                char *path = get_path(f, node->nodeid);
                if (path) {
                    f->op.unlink(path);
                    free(path);
                }
            }
        }
    }
    for (i = 0; i < f->id_table_size; i++) {
        struct node *node;
        struct node *next;

        for (node = f->id_table[i]; node != NULL; node = next) {
            next = node->id_next;
            free_node(node);
        }
    }
    free(f->id_table);
    free(f->name_table);
    pthread_mutex_destroy(&f->lock);
    pthread_mutex_destroy(&f->worker_lock);
    if (f->op.destroy)
        f->op.destroy(f->user_data);
    free(f);
}

__asm__(".symver fuse_exited,__fuse_exited@");
__asm__(".symver fuse_process_cmd,__fuse_process_cmd@");
__asm__(".symver fuse_read_cmd,__fuse_read_cmd@");
__asm__(".symver fuse_set_getcontext_func,__fuse_set_getcontext_func@");
__asm__(".symver fuse_new_compat2,fuse_new@");