1 files changed, 273 insertions, 0 deletions
diff --git a/source3/modules/vfs_glusterfs_fuse.c b/source3/modules/vfs_glusterfs_fuse.c
new file mode 100644
index 0000000..88c740c
--- /dev/null
+++ b/source3/modules/vfs_glusterfs_fuse.c
@@ -0,0 +1,273 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Copyright (c) 2019 Guenther Deschner <gd@samba.org>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "smbd/smbd.h"
+#include "system/filesys.h"
+
+#define GLUSTER_NAME_MAX 255
+
+static NTSTATUS vfs_gluster_fuse_get_real_filename_at(
+	struct vfs_handle_struct *handle,
+	struct files_struct *dirfsp,
+	const char *name,
+	TALLOC_CTX *mem_ctx,
+	char **_found_name)
+{
+	int ret, dirfd;
+	char key_buf[GLUSTER_NAME_MAX + 64];
+	char val_buf[GLUSTER_NAME_MAX + 1];
+	char *found_name = NULL;
+
+	if (strlen(name) >= GLUSTER_NAME_MAX) {
+		return NT_STATUS_OBJECT_NAME_INVALID;
+	}
+
+	snprintf(key_buf, GLUSTER_NAME_MAX + 64,
+		 "glusterfs.get_real_filename:%s", name);
+
+	dirfd = openat(fsp_get_pathref_fd(dirfsp), ".", O_RDONLY);
+	if (dirfd == -1) {
+		NTSTATUS status = map_nt_error_from_unix(errno);
+		DBG_DEBUG("Could not open '.' in %s: %s\n",
+			  fsp_str_dbg(dirfsp),
+			  strerror(errno));
+		return status;
+	}
+
+	ret = fgetxattr(dirfd, key_buf, val_buf, GLUSTER_NAME_MAX + 1);
+	close(dirfd);
+	if (ret == -1) {
+		if (errno == ENOATTR) {
+			errno = ENOENT;
+		}
+		return map_nt_error_from_unix(errno);
+	}
+
+	found_name = talloc_strdup(mem_ctx, val_buf);
+	if (found_name == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	*_found_name = found_name;
+	return NT_STATUS_OK;
+}
+
+struct device_mapping_entry {
+	SMB_DEV_T device;       /* the local device, for reference */
+	uint64_t mapped_device; /* the mapped device */
+};
+
+struct vfs_glusterfs_fuse_handle_data {
+	unsigned num_mapped_devices;
+	struct device_mapping_entry *mapped_devices;
+};
+
+/* a 64 bit hash, based on the one in tdb, copied from vfs_fileied */
+static uint64_t vfs_glusterfs_fuse_uint64_hash(const uint8_t *s, size_t len)
+{
+	uint64_t value; /* Used to compute the hash value.  */
+	uint32_t i;     /* Used to cycle through random values. */
+
+	/* Set the initial value from the key size. */
+	for (value = 0x238F13AFLL * len, i=0; i < len; i++)
+		value = (value + (((uint64_t)s[i]) << (i*5 % 24)));
+
+	return (1103515243LL * value + 12345LL);
+}
+
+static void vfs_glusterfs_fuse_load_devices(
+		struct vfs_glusterfs_fuse_handle_data *data)
+{
+	FILE *f;
+	struct mntent *m;
+
+	data->num_mapped_devices = 0;
+	TALLOC_FREE(data->mapped_devices);
+
+	f = setmntent("/etc/mtab", "r");
+	if (!f) {
+		return;
+	}
+
+	while ((m = getmntent(f))) {
+		struct stat st;
+		char *p;
+		uint64_t mapped_device;
+
+		if (stat(m->mnt_dir, &st) != 0) {
+			/* TODO: log? */
+			continue;
+		}
+
+		/* strip the host part off of the fsname */
+		p = strrchr(m->mnt_fsname, ':');
+		if (p == NULL) {
+			p = m->mnt_fsname;
+		} else {
+			/* TODO: consider the case of '' ? */
+			p++;
+		}
+
+		mapped_device = vfs_glusterfs_fuse_uint64_hash(
+						(const uint8_t *)p,
+						strlen(p));
+
+		data->mapped_devices = talloc_realloc(data,
+						data->mapped_devices,
+						struct device_mapping_entry,
+						data->num_mapped_devices + 1);
+		if (data->mapped_devices == NULL) {
+			goto nomem;
+		}
+
+		data->mapped_devices[data->num_mapped_devices].device =
+								st.st_dev;
+		data->mapped_devices[data->num_mapped_devices].mapped_device =
+								mapped_device;
+
+		data->num_mapped_devices++;
+	}
+
+	endmntent(f);
+	return;
+
+nomem:
+	data->num_mapped_devices = 0;
+	TALLOC_FREE(data->mapped_devices);
+
+	endmntent(f);
+	return;
+}
+
+static int vfs_glusterfs_fuse_map_device_cached(
+				struct vfs_glusterfs_fuse_handle_data *data,
+				SMB_DEV_T device,
+				uint64_t *mapped_device)
+{
+	unsigned i;
+
+	for (i = 0; i < data->num_mapped_devices; i++) {
+		if (data->mapped_devices[i].device == device) {
+			*mapped_device = data->mapped_devices[i].mapped_device;
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
+static int vfs_glusterfs_fuse_map_device(
+				struct vfs_glusterfs_fuse_handle_data *data,
+				SMB_DEV_T device,
+				uint64_t *mapped_device)
+{
+	int ret;
+
+	ret = vfs_glusterfs_fuse_map_device_cached(data, device, mapped_device);
+	if (ret == 0) {
+		return 0;
+	}
+
+	vfs_glusterfs_fuse_load_devices(data);
+
+	ret = vfs_glusterfs_fuse_map_device_cached(data, device, mapped_device);
+
+	return ret;
+}
+
+static struct file_id vfs_glusterfs_fuse_file_id_create(
+			struct vfs_handle_struct *handle,
+			const SMB_STRUCT_STAT *sbuf)
+{
+	struct vfs_glusterfs_fuse_handle_data *data;
+	struct file_id id;
+	uint64_t mapped_device;
+	int ret;
+
+	ZERO_STRUCT(id);
+
+	id = SMB_VFS_NEXT_FILE_ID_CREATE(handle, sbuf);
+
+	SMB_VFS_HANDLE_GET_DATA(handle, data,
+				struct vfs_glusterfs_fuse_handle_data,
+				return id);
+
+	ret = vfs_glusterfs_fuse_map_device(data, sbuf->st_ex_dev,
+					    &mapped_device);
+	if (ret == 0) {
+		id.devid = mapped_device;
+	} else {
+		DBG_WARNING("Failed to map device [%jx], falling back to "
+			    "standard file_id [%jx]\n",
+			    (uintmax_t)sbuf->st_ex_dev,
+			    (uintmax_t)id.devid);
+	}
+
+	DBG_DEBUG("Returning dev [%jx] inode [%jx]\n",
+		  (uintmax_t)id.devid, (uintmax_t)id.inode);
+
+	return id;
+}
+
+static int vfs_glusterfs_fuse_connect(struct vfs_handle_struct *handle,
+				      const char *service, const char *user)
+{
+	struct vfs_glusterfs_fuse_handle_data *data;
+	int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
+
+	if (ret < 0) {
+		return ret;
+	}
+
+	data = talloc_zero(handle->conn, struct vfs_glusterfs_fuse_handle_data);
+	if (data == NULL) {
+		DBG_ERR("talloc_zero() failed.\n");
+		SMB_VFS_NEXT_DISCONNECT(handle);
+		return -1;
+	}
+
+	/*
+	 * Fill the cache in the tree connect, so that the first file/dir access
+	 * has chances of being fast...
+	 */
+	vfs_glusterfs_fuse_load_devices(data);
+
+	SMB_VFS_HANDLE_SET_DATA(handle, data, NULL,
+				struct vfs_glusterfs_fuse_handle_data,
+				return -1);
+
+	DBG_DEBUG("vfs_glusterfs_fuse_connect(): connected to service[%s]\n",
+		  service);
+
+	return 0;
+}
+
+struct vfs_fn_pointers glusterfs_fuse_fns = {
+
+	.connect_fn = vfs_glusterfs_fuse_connect,
+	.get_real_filename_at_fn = vfs_gluster_fuse_get_real_filename_at,
+	.file_id_create_fn = vfs_glusterfs_fuse_file_id_create,
+};
+
+static_decl_vfs;
+NTSTATUS vfs_glusterfs_fuse_init(TALLOC_CTX *ctx)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
+				"glusterfs_fuse", &glusterfs_fuse_fns);
+}