fuse.c

UNIX/LINUX下面的用户文件系统

static void forget_node(struct fuse *f, fuse_ino_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 remove_node(struct fuse *f, fuse_ino_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, fuse_ino_t olddir, const char *oldname,
                        fuse_ino_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 set_stat(struct fuse *f, fuse_ino_t nodeid, struct stat *stbuf)
{
    if (!f->conf.use_ino)
        stbuf->st_ino = nodeid;
    if (f->conf.set_mode)
        stbuf->st_mode = (stbuf->st_mode & S_IFMT) | (0777 & ~f->conf.umask);
    if (f->conf.set_uid)
        stbuf->st_uid = f->conf.uid;
    if (f->conf.set_gid)
        stbuf->st_gid = f->conf.gid;
}

static struct fuse *req_fuse(fuse_req_t req)
{
    return (struct fuse *) fuse_req_userdata(req);
}

static void fuse_intr_sighandler(int sig)
{
    (void) sig;
    /* Nothing to do */
}

struct fuse_intr_data {
    pthread_t id;
    pthread_cond_t cond;
    int finished;
};

static void fuse_interrupt(fuse_req_t req, void *d_)
{
    struct fuse_intr_data *d = d_;
    struct fuse *f = req_fuse(req);

    if (d->id == pthread_self())
        return;

    pthread_mutex_lock(&f->lock);
    while (!d->finished) {
        struct timeval now;
        struct timespec timeout;

        pthread_kill(d->id, f->conf.intr_signal);
        gettimeofday(&now, NULL);
        timeout.tv_sec = now.tv_sec + 1;
        timeout.tv_nsec = now.tv_usec * 1000;
        pthread_cond_timedwait(&d->cond, &f->lock, &timeout);
    }
    pthread_mutex_unlock(&f->lock);
}

static void fuse_do_finish_interrupt(struct fuse *f, fuse_req_t req,
                                     struct fuse_intr_data *d)
{
    pthread_mutex_lock(&f->lock);
    d->finished = 1;
    pthread_cond_broadcast(&d->cond);
    pthread_mutex_unlock(&f->lock);
    fuse_req_interrupt_func(req, NULL, NULL);
    pthread_cond_destroy(&d->cond);
}

static void fuse_do_prepare_interrupt(fuse_req_t req, struct fuse_intr_data *d)
{
    d->id = pthread_self();
    pthread_cond_init(&d->cond, NULL);
    d->finished = 0;
    fuse_req_interrupt_func(req, fuse_interrupt, d);
}

static inline void fuse_finish_interrupt(struct fuse *f, fuse_req_t req,
                                         struct fuse_intr_data *d)
{
    if (f->conf.intr)
        fuse_do_finish_interrupt(f, req, d);
}

static inline void fuse_prepare_interrupt(struct fuse *f, fuse_req_t req,
                                          struct fuse_intr_data *d)
{
    if (f->conf.intr)
        fuse_do_prepare_interrupt(req, d);
}

#ifndef __FreeBSD__

static int fuse_compat_open(struct fuse_fs *fs, const char *path,
                            struct fuse_file_info *fi)
{
    int err;
    if (!fs->compat || fs->compat >= 25)
        err = fs->op.open(path, fi);
    else if (fs->compat == 22) {
        struct fuse_file_info_compat tmp;
        memcpy(&tmp, fi, sizeof(tmp));
        err = ((struct fuse_operations_compat22 *) &fs->op)->open(path, &tmp);
        memcpy(fi, &tmp, sizeof(tmp));
        fi->fh = tmp.fh;
    } else
        err = ((struct fuse_operations_compat2 *) &fs->op)
            ->open(path, fi->flags);
    return err;
}

static int fuse_compat_release(struct fuse_fs *fs, const char *path,
                               struct fuse_file_info *fi)
{
    if (!fs->compat || fs->compat >= 22)
        return fs->op.release(path, fi);
    else
        return ((struct fuse_operations_compat2 *) &fs->op)
            ->release(path, fi->flags);
}

static int fuse_compat_opendir(struct fuse_fs *fs, const char *path,
                               struct fuse_file_info *fi)
{
    if (!fs->compat || fs->compat >= 25)
        return fs->op.opendir(path, fi);
    else {
        int err;
        struct fuse_file_info_compat tmp;
        memcpy(&tmp, fi, sizeof(tmp));
        err = ((struct fuse_operations_compat22 *) &fs->op)
            ->opendir(path, &tmp);
        memcpy(fi, &tmp, sizeof(tmp));
        fi->fh = tmp.fh;
        return err;
    }
}

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

static void convert_statfs_old(struct statfs *oldbuf, struct statvfs *stbuf)
{
    stbuf->f_bsize   = oldbuf->f_bsize;
    stbuf->f_blocks  = oldbuf->f_blocks;
    stbuf->f_bfree   = oldbuf->f_bfree;
    stbuf->f_bavail  = oldbuf->f_bavail;
    stbuf->f_files   = oldbuf->f_files;
    stbuf->f_ffree   = oldbuf->f_ffree;
    stbuf->f_namemax = oldbuf->f_namelen;
}

static int fuse_compat_statfs(struct fuse_fs *fs, const char *path,
                              struct statvfs *buf)
{
    int err;

    if (!fs->compat || fs->compat >= 25) {
        err = fs->op.statfs(fs->compat == 25 ? "/" : path, buf);
    } else if (fs->compat > 11) {
        struct statfs oldbuf;
        err = ((struct fuse_operations_compat22 *) &fs->op)
            ->statfs("/", &oldbuf);
        if (!err)
            convert_statfs_old(&oldbuf, buf);
    } else {
        struct fuse_statfs_compat1 compatbuf;
        memset(&compatbuf, 0, sizeof(struct fuse_statfs_compat1));
        err = ((struct fuse_operations_compat1 *) &fs->op)->statfs(&compatbuf);
        if (!err)
            convert_statfs_compat(&compatbuf, buf);
    }
    return err;
}

#else /* __FreeBSD__ */

static inline int fuse_compat_open(struct fuse_fs *fs, char *path,
                                   struct fuse_file_info *fi)
{
    return fs->op.open(path, fi);
}

static inline int fuse_compat_release(struct fuse_fs *fs, const char *path,
                                      struct fuse_file_info *fi)
{
    return fs->op.release(path, fi);
}

static inline int fuse_compat_opendir(struct fuse_fs *fs, const char *path,
                                      struct fuse_file_info *fi)
{
    return fs->op.opendir(path, fi);
}

static inline int fuse_compat_statfs(struct fuse_fs *fs, const char *path,
                                     struct statvfs *buf)
{
    return fs->op.statfs(fs->compat == 25 ? "/" : path, buf);
}

#endif /* __FreeBSD__ */

int fuse_fs_getattr(struct fuse_fs *fs, const char *path, struct stat *buf)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.getattr)
        return fs->op.getattr(path, buf);
    else
        return -ENOSYS;
}

int fuse_fs_fgetattr(struct fuse_fs *fs, const char *path, struct stat *buf,
                     struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.fgetattr)
        return fs->op.fgetattr(path, buf, fi);
    else if (fs->op.getattr)
        return fs->op.getattr(path, buf);
    else
        return -ENOSYS;
}

int fuse_fs_rename(struct fuse_fs *fs, const char *oldpath,
                   const char *newpath)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.rename)
        return fs->op.rename(oldpath, newpath);
    else
        return -ENOSYS;
}

int fuse_fs_unlink(struct fuse_fs *fs, const char *path)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.unlink)
        return fs->op.unlink(path);
    else
        return -ENOSYS;
}

int fuse_fs_rmdir(struct fuse_fs *fs, const char *path)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.rmdir)
        return fs->op.rmdir(path);
    else
        return -ENOSYS;
}

int fuse_fs_symlink(struct fuse_fs *fs, const char *linkname, const char *path)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.symlink)
        return fs->op.symlink(linkname, path);
    else
        return -ENOSYS;
}

int fuse_fs_link(struct fuse_fs *fs, const char *oldpath, const char *newpath)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.link)
        return fs->op.link(oldpath, newpath);
    else
        return -ENOSYS;
}

int fuse_fs_release(struct fuse_fs *fs,  const char *path,
                    struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.release)
        return fuse_compat_release(fs, path, fi);
    else
        return 0;
}

int fuse_fs_opendir(struct fuse_fs *fs, const char *path,
                    struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.opendir)
        return fuse_compat_opendir(fs, path, fi);
    else
        return 0;
}

int fuse_fs_open(struct fuse_fs *fs, const char *path,
                 struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.open)
        return fuse_compat_open(fs, path, fi);
    else
        return 0;
}

int fuse_fs_read(struct fuse_fs *fs, const char *path, char *buf, size_t size,
                 off_t off, struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.read)
        return fs->op.read(path, buf, size, off, fi);
    else
        return -ENOSYS;
}

int fuse_fs_write(struct fuse_fs *fs, const char *path, const char *buf,
                  size_t size, off_t off, struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.write)
        return fs->op.write(path, buf, size, off, fi);
    else
        return -ENOSYS;
}

int fuse_fs_fsync(struct fuse_fs *fs, const char *path, int datasync,
                  struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.fsync)
        return fs->op.fsync(path, datasync, fi);
    else
        return -ENOSYS;
}

int fuse_fs_fsyncdir(struct fuse_fs *fs, const char *path, int datasync,
                     struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.fsyncdir)
        return fs->op.fsyncdir(path, datasync, fi);
    else
        return -ENOSYS;
}

int fuse_fs_flush(struct fuse_fs *fs, const char *path,
                  struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.flush)
        return fs->op.flush(path, fi);
    else
        return -ENOSYS;
}

int fuse_fs_statfs(struct fuse_fs *fs, const char *path, struct statvfs *buf)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.statfs)
        return fuse_compat_statfs(fs, path, buf);
    else {
        buf->f_namemax = 255;
        buf->f_bsize = 512;
        return 0;
    }
}

int fuse_fs_releasedir(struct fuse_fs *fs, const char *path,
                       struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.releasedir)
        return fs->op.releasedir(path, fi);
    else
        return 0;
}

static int fill_dir_old(struct fuse_dirhandle *dh, const char *name, int type,
                        ino_t ino)
{
    int res;
    struct stat stbuf;

    memset(&stbuf, 0, sizeof(stbuf));
    stbuf.st_mode = type << 12;
    stbuf.st_ino = ino;

    res = dh->filler(dh->buf, name, &stbuf, 0);
    return res ? -ENOMEM : 0;
}

int fuse_fs_readdir(struct fuse_fs *fs, const char *path, void *buf,
                    fuse_fill_dir_t filler, off_t off,
                    struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.readdir)
        return fs->op.readdir(path, buf, filler, off, fi);
    else if (fs->op.getdir) {
        struct fuse_dirhandle dh;
        dh.filler = filler;
        dh.buf = buf;
        return fs->op.getdir(path, &dh, fill_dir_old);
    } else
        return -ENOSYS;
}

int fuse_fs_create(struct fuse_fs *fs, const char *path, mode_t mode,
                   struct fuse_file_info *fi)
{
    fuse_get_context()->private_data = fs->user_data;
    if (fs->op.create)
        return fs->op.create(path, mode, fi);
    else