fuse.c

FUSE文件系统开发工具,将内核层面的文件系统开发过程平移到应用层面上来。

	struct fuse_dh *dh = get_dirhandle(llfi, &fi);
	char *path;

	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	fuse_prepare_interrupt(f, req, &d);
	fuse_fs_releasedir(f->fs, path ? path : "-", &fi);
	fuse_finish_interrupt(f, req, &d);
	if (path)
		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);
	reply_err(req, 0);
}

static void fuse_lib_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync,
			      struct fuse_file_info *llfi)
{
	struct fuse *f = req_fuse_prepare(req);
	struct fuse_file_info fi;
	char *path;
	int err;

	get_dirhandle(llfi, &fi);

	err = -ENOENT;
	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path != NULL) {
		struct fuse_intr_data d;
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_fsyncdir(f->fs, path, datasync, &fi);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);
	reply_err(req, err);
}

static void fuse_lib_statfs(fuse_req_t req, fuse_ino_t ino)
{
	struct fuse *f = req_fuse_prepare(req);
	struct statvfs buf;
	char *path;
	int err;

	memset(&buf, 0, sizeof(buf));
	pthread_rwlock_rdlock(&f->tree_lock);
	if (!ino) {
		err = -ENOMEM;
		path = strdup("/");
	} else {
		err = -ENOENT;
		path = get_path(f, ino);
	}
	if (path) {
		struct fuse_intr_data d;
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_statfs(f->fs, path, &buf);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);

	if (!err)
		fuse_reply_statfs(req, &buf);
	else
		reply_err(req, err);
}

static void fuse_lib_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
			      const char *value, size_t size, int flags)
{
	struct fuse *f = req_fuse_prepare(req);
	char *path;
	int err;

	err = -ENOENT;
	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path != NULL) {
		struct fuse_intr_data d;
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_setxattr(f->fs, path, name, value, size, flags);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);
	reply_err(req, err);
}

static int common_getxattr(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
			   const char *name, char *value, size_t size)
{
	int err;
	char *path;

	err = -ENOENT;
	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path != NULL) {
		struct fuse_intr_data d;
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_getxattr(f->fs, path, name, value, size);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);
	return err;
}

static void fuse_lib_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
			      size_t size)
{
	struct fuse *f = req_fuse_prepare(req);
	int res;

	if (size) {
		char *value = (char *) malloc(size);
		if (value == NULL) {
			reply_err(req, -ENOMEM);
			return;
		}
		res = common_getxattr(f, req, ino, name, value, size);
		if (res > 0)
			fuse_reply_buf(req, value, res);
		else
			reply_err(req, res);
		free(value);
	} else {
		res = common_getxattr(f, req, ino, name, NULL, 0);
		if (res >= 0)
			fuse_reply_xattr(req, res);
		else
			reply_err(req, res);
	}
}

static int common_listxattr(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
			    char *list, size_t size)
{
	char *path;
	int err;

	err = -ENOENT;
	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path != NULL) {
		struct fuse_intr_data d;
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_listxattr(f->fs, path, list, size);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);
	return err;
}

static void fuse_lib_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
{
	struct fuse *f = req_fuse_prepare(req);
	int res;

	if (size) {
		char *list = (char *) malloc(size);
		if (list == NULL) {
			reply_err(req, -ENOMEM);
			return;
		}
		res = common_listxattr(f, req, ino, list, size);
		if (res > 0)
			fuse_reply_buf(req, list, res);
		else
			reply_err(req, res);
		free(list);
	} else {
		res = common_listxattr(f, req, ino, NULL, 0);
		if (res >= 0)
			fuse_reply_xattr(req, res);
		else
			reply_err(req, res);
	}
}

static void fuse_lib_removexattr(fuse_req_t req, fuse_ino_t ino,
				 const char *name)
{
	struct fuse *f = req_fuse_prepare(req);
	char *path;
	int err;

	err = -ENOENT;
	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path != NULL) {
		struct fuse_intr_data d;
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_removexattr(f->fs, path, name);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);
	reply_err(req, err);
}

static struct lock *locks_conflict(struct node *node, const struct lock *lock)
{
	struct lock *l;

	for (l = node->locks; l; l = l->next)
		if (l->owner != lock->owner &&
		    lock->start <= l->end && l->start <= lock->end &&
		    (l->type == F_WRLCK || lock->type == F_WRLCK))
			break;

	return l;
}

static void delete_lock(struct lock **lockp)
{
	struct lock *l = *lockp;
	*lockp = l->next;
	free(l);
}

static void insert_lock(struct lock **pos, struct lock *lock)
{
	lock->next = *pos;
	*pos = lock;
}

static int locks_insert(struct node *node, struct lock *lock)
{
	struct lock **lp;
	struct lock *newl1 = NULL;
	struct lock *newl2 = NULL;

	if (lock->type != F_UNLCK || lock->start != 0 ||
	    lock->end != OFFSET_MAX) {
		newl1 = malloc(sizeof(struct lock));
		newl2 = malloc(sizeof(struct lock));

		if (!newl1 || !newl2) {
			free(newl1);
			free(newl2);
			return -ENOLCK;
		}
	}

	for (lp = &node->locks; *lp;) {
		struct lock *l = *lp;
		if (l->owner != lock->owner)
			goto skip;

		if (lock->type == l->type) {
			if (l->end < lock->start - 1)
				goto skip;
			if (lock->end < l->start - 1)
				break;
			if (l->start <= lock->start && lock->end <= l->end)
				goto out;
			if (l->start < lock->start)
				lock->start = l->start;
			if (lock->end < l->end)
				lock->end = l->end;
			goto delete;
		} else {
			if (l->end < lock->start)
				goto skip;
			if (lock->end < l->start)
				break;
			if (lock->start <= l->start && l->end <= lock->end)
				goto delete;
			if (l->end <= lock->end) {
				l->end = lock->start - 1;
				goto skip;
			}
			if (lock->start <= l->start) {
				l->start = lock->end + 1;
				break;
			}
			*newl2 = *l;
			newl2->start = lock->end + 1;
			l->end = lock->start - 1;
			insert_lock(&l->next, newl2);
			newl2 = NULL;
		}
	skip:
		lp = &l->next;
		continue;

	delete:
		delete_lock(lp);
	}
	if (lock->type != F_UNLCK) {
		*newl1 = *lock;
		insert_lock(lp, newl1);
		newl1 = NULL;
	}
out:
	free(newl1);
	free(newl2);
	return 0;
}

static void flock_to_lock(struct flock *flock, struct lock *lock)
{
	memset(lock, 0, sizeof(struct lock));
	lock->type = flock->l_type;
	lock->start = flock->l_start;
	lock->end =
		flock->l_len ? flock->l_start + flock->l_len - 1 : OFFSET_MAX;
	lock->pid = flock->l_pid;
}

static void lock_to_flock(struct lock *lock, struct flock *flock)
{
	flock->l_type = lock->type;
	flock->l_start = lock->start;
	flock->l_len =
		(lock->end == OFFSET_MAX) ? 0 : lock->end - lock->start + 1;
	flock->l_pid = lock->pid;
}

static int fuse_flush_common(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
			     const char *path, struct fuse_file_info *fi)
{
	struct fuse_intr_data d;
	struct flock lock;
	struct lock l;
	int err;
	int errlock;

	fuse_prepare_interrupt(f, req, &d);
	memset(&lock, 0, sizeof(lock));
	lock.l_type = F_UNLCK;
	lock.l_whence = SEEK_SET;
	err = fuse_fs_flush(f->fs, path, fi);
	errlock = fuse_fs_lock(f->fs, path, fi, F_SETLK, &lock);
	fuse_finish_interrupt(f, req, &d);

	if (errlock != -ENOSYS) {
		flock_to_lock(&lock, &l);
		l.owner = fi->lock_owner;
		pthread_mutex_lock(&f->lock);
		locks_insert(get_node(f, ino), &l);
		pthread_mutex_unlock(&f->lock);

		/* if op.lock() is defined FLUSH is needed regardless
		   of op.flush() */
		if (err == -ENOSYS)
			err = 0;
	}
	return err;
}

static void fuse_lib_release(fuse_req_t req, fuse_ino_t ino,
			     struct fuse_file_info *fi)
{
	struct fuse *f = req_fuse_prepare(req);
	struct fuse_intr_data d;
	char *path;
	int err = 0;

	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (f->conf.debug)
		fprintf(stderr, "RELEASE%s[%llu] flags: 0x%x\n",
			fi->flush ? "+FLUSH" : "",
			(unsigned long long) fi->fh, fi->flags);

	if (fi->flush) {
		err = fuse_flush_common(f, req, ino, path, fi);
		if (err == -ENOSYS)
			err = 0;
	}

	fuse_prepare_interrupt(f, req, &d);
	fuse_do_release(f, ino, path, fi);
	fuse_finish_interrupt(f, req, &d);
	free(path);
	pthread_rwlock_unlock(&f->tree_lock);

	reply_err(req, err);
}

static void fuse_lib_flush(fuse_req_t req, fuse_ino_t ino,
			   struct fuse_file_info *fi)
{
	struct fuse *f = req_fuse_prepare(req);
	char *path;
	int err;

	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path && f->conf.debug)
		fprintf(stderr, "FLUSH[%llu]\n", (unsigned long long) fi->fh);
	err = fuse_flush_common(f, req, ino, path, fi);
	free(path);
	pthread_rwlock_unlock(&f->tree_lock);
	reply_err(req, err);
}

static int fuse_lock_common(fuse_req_t req, fuse_ino_t ino,
			    struct fuse_file_info *fi, struct flock *lock,
			    int cmd)
{
	struct fuse *f = req_fuse_prepare(req);
	char *path;
	int err;

	err = -ENOENT;
	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path != NULL) {
		struct fuse_intr_data d;
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_lock(f->fs, path, fi, cmd, lock);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);
	return err;
}

static void fuse_lib_getlk(fuse_req_t req, fuse_ino_t ino,
			   struct fuse_file_info *fi, struct flock *lock)
{
	int err;
	struct lock l;
	struct lock *conflict;
	struct fuse *f = req_fuse(req);

	flock_to_lock(lock, &l);
	l.owner = fi->lock_owner;
	pthread_mutex_lock(&f->lock);
	conflict = locks_conflict(get_node(f, ino), &l);
	if (conflict)
		lock_to_flock(conflict, lock);
	pthread_mutex_unlock(&f->lock);
	if (!conflict)
		err = fuse_lock_common(req, ino, fi, lock, F_GETLK);
	else
		err = 0;

	if (!err)
		fuse_reply_lock(req, lock);
	else
		reply_err(req, err);
}

static void fuse_lib_setlk(fuse_req_t req, fuse_ino_t ino,
			   struct fuse_file_info *fi, struct flock *lock,
			   int sleep)
{
	int err = fuse_lock_common(req, ino, fi, lock,
				   sleep ? F_SETLKW : F_SETLK);
	if (!err) {
		struct fuse *f = req_fuse(req);
		struct lock l;
		flock_to_lock(lock, &l);
		l.owner = fi->lock_owner;
		pthread_mutex_lock(&f->lock);
		locks_insert(get_node(f, ino), &l);
		pthread_mutex_unlock(&f->lock);
	}
	reply_err(req, err);
}

static void fuse_lib_bmap(fuse_req_t req, fuse_ino_t ino, size_t blocksize,
			  uint64_t idx)
{
	struct fuse *f = req_fuse_prepare(req);
	struct fuse_intr_data d;
	char *path;
	int err;

	err = -ENOENT;
	pthread_rwlock_rdlock(&f->tree_lock);
	path = get_path(f, ino);
	if (path != NULL) {
		fuse_prepare_interrupt(f, req, &d);
		err = fuse_fs_bmap(f->fs, path, blocksize, &idx);
		fuse_finish_interrupt(f, req, &d);
		free(path);
	}
	pthread_rwlock_unlock(&f->tree_lock);
	if (!err)
		fuse_reply_bmap(req, idx);
	else
		reply_err(req, err);
}

static struct fuse_lowlevel_ops fuse_path_ops = {
	.init = fuse_lib_init,
	.destroy = fuse_lib_destroy,
	.lookup = fuse_lib_lookup,
	.forget = fuse_lib_forget,
	.getattr = fuse_lib_getattr,
	.setattr = fuse_lib_setattr,
	.access = fuse_lib_access,
	.readlink = fuse_lib_readlink,
	.mknod = fuse_lib_mknod,
	.mkdir = fuse_lib_mkdir,
	.unlink = fuse_lib_unlink,
	.rmdir = fuse_lib_rmdir,
	.symlink = fuse_lib_symlink,
	.rename = fuse_lib_rename,
	.link = fuse_lib_link,
	.create = fuse_lib_create,
	.open = fuse_lib_open,
	.read = fuse_lib_read,
	.write = fuse_lib_write,
	.flush = fuse_lib_flush,
	.release = fuse_lib_release,
	.fsync = fuse_lib_fsync,
	.opendir = fuse_lib_opendir,
	.readdir = fuse_lib_readdir,
	.releasedir = fuse_lib_releasedir,
	.fsyncdir = fuse_lib_fsyncdir,
	.statfs = fuse_lib_statfs,
	.setxattr = fuse_lib_setxattr,
	.getxattr = fuse_lib_getxattr,
	.listxattr = fuse_lib_listxattr,
	.removexattr = fuse_lib_removexattr,
	.getlk = fuse_lib_getlk,
	.setlk = fuse_lib_setlk,
	.bmap = fuse_lib_bmap,
};

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

void fuse_process_cmd(struct fuse *f, struct fuse_cmd *cmd)
{
	fuse_session_process(f->se, cmd->buf, cmd->buflen, cmd->ch);
	free_cmd(cmd);
}

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

struct fuse_session *fuse_get_session(struct fuse *f)
{
	return f->se;
}

static struct fuse_cmd *fuse_alloc_cmd(size_t bufsize)
{
	struct fuse_cmd *cmd = (struct fuse_cmd *) malloc(sizeof(*cmd));
	if (cmd == NULL) {
		fprintf(stderr, "fuse: failed to