/*
 * VFS module to disallow writes for older files
 *
 * Copyright (C) 2013, Volker Lendecke
 *
 * 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"
#include "libcli/security/security.h"

static NTSTATUS vfs_worm_create_file(vfs_handle_struct *handle,
				     struct smb_request *req,
				     struct files_struct *dirfsp,
				     struct smb_filename *smb_fname,
				     uint32_t access_mask,
				     uint32_t share_access,
				     uint32_t create_disposition,
				     uint32_t create_options,
				     uint32_t file_attributes,
				     uint32_t oplock_request,
				     const struct smb2_lease *lease,
				     uint64_t allocation_size,
				     uint32_t private_flags,
				     struct security_descriptor *sd,
				     struct ea_list *ea_list,
				     files_struct **result,
				     int *pinfo,
				     const struct smb2_create_blobs *in_context_blobs,
				     struct smb2_create_blobs *out_context_blobs)
{
	bool readonly = false;
	const uint32_t write_access_flags =
		FILE_WRITE_DATA | FILE_APPEND_DATA |
		FILE_WRITE_ATTRIBUTES | DELETE_ACCESS |
		WRITE_DAC_ACCESS | WRITE_OWNER_ACCESS;
	NTSTATUS status;

	if (VALID_STAT(smb_fname->st)) {
		double age;
		age = timespec_elapsed(&smb_fname->st.st_ex_ctime);
		if (age > lp_parm_int(SNUM(handle->conn), "worm",
				      "grace_period", 3600)) {
			readonly = true;
		}
	}

	if (readonly && (access_mask & write_access_flags)) {
		return NT_STATUS_ACCESS_DENIED;
	}

	status = SMB_VFS_NEXT_CREATE_FILE(
		handle, req, dirfsp, smb_fname, access_mask,
		share_access, create_disposition, create_options,
		file_attributes, oplock_request, lease, allocation_size,
		private_flags, sd, ea_list, result, pinfo,
		in_context_blobs, out_context_blobs);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	/*
	 * Access via MAXIMUM_ALLOWED_ACCESS?
	 */
	if (readonly && ((*result)->access_mask & write_access_flags)) {
		close_file_free(req, result, NORMAL_CLOSE);
		return NT_STATUS_ACCESS_DENIED;
	}
	return NT_STATUS_OK;
}

static struct vfs_fn_pointers vfs_worm_fns = {
	.create_file_fn = vfs_worm_create_file,
};

static_decl_vfs;
NTSTATUS vfs_worm_init(TALLOC_CTX *ctx)
{
	NTSTATUS ret;

	ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "worm",
			       &vfs_worm_fns);
	if (!NT_STATUS_IS_OK(ret)) {
		return ret;
	}

	return ret;
}