/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 The FreeBSD Foundation
 *
 * This software was developed by BFF Storage Systems, LLC under sponsorship
 * from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

extern "C" {
#include <sys/types.h>
#include <sys/mount.h>

#include <fcntl.h>
#include <semaphore.h>
#include <unistd.h>
}

#include "mockfs.hh"
#include "utils.hh"

using namespace testing;

class Forget: public FuseTest {
public:
void SetUp() {
        if (geteuid() != 0)
                GTEST_SKIP() << "Only root may use " << reclaim_mib;

        FuseTest::SetUp();
}

};

/*
 * When a fusefs vnode is reclaimed, it should send a FUSE_FORGET operation.
 */
TEST_F(Forget, ok)
{
        const char FULLPATH[] = "mountpoint/some_file.txt";
        const char RELPATH[] = "some_file.txt";
        uint64_t ino = 42;
        mode_t mode = S_IFREG | 0755;
        sem_t sem;

        ASSERT_EQ(0, sem_init(&sem, 0, 0)) << strerror(errno);

        EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
        .Times(3)
        .WillRepeatedly(Invoke(
                ReturnImmediate([=](auto in __unused, auto& out) {
                SET_OUT_HEADER_LEN(out, entry);
                out.body.entry.attr.mode = mode;
                out.body.entry.nodeid = ino;
                out.body.entry.attr.nlink = 1;
                out.body.entry.attr_valid = UINT64_MAX;
        })));
        expect_forget(ino, 3, &sem);

        /*
         * access(2) the file to force a lookup.  Access it twice to double its
         * lookup count.
         */
        ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
        ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);

        reclaim_vnode(FULLPATH);

        sem_wait(&sem);
        sem_destroy(&sem);
}

/*
 * When a directory is reclaimed, the names of its entries vanish from the
 * namecache
 */
TEST_F(Forget, invalidate_names)
{
        const char FULLFPATH[] = "mountpoint/some_dir/some_file.txt";
        const char FULLDPATH[] = "mountpoint/some_dir";
        const char DNAME[] = "some_dir";
        const char FNAME[] = "some_file.txt";
        uint64_t dir_ino = 42;
        uint64_t file_ino = 43;

        EXPECT_LOOKUP(FUSE_ROOT_ID, DNAME)
        .Times(2)
        .WillRepeatedly(Invoke(
                ReturnImmediate([=](auto in __unused, auto& out) {
                SET_OUT_HEADER_LEN(out, entry);
                out.body.entry.attr.mode = S_IFDIR | 0755;
                out.body.entry.nodeid = dir_ino;
                out.body.entry.attr.nlink = 2;
                out.body.entry.attr_valid = UINT64_MAX;
                out.body.entry.entry_valid = UINT64_MAX;
        })));

        /* 
         * Even though we don't reclaim FNAME and its entry is cacheable, we
         * should get two lookups because the reclaim of DNAME will invalidate
         * the cached FNAME entry.
         */
        EXPECT_LOOKUP(dir_ino, FNAME)
        .Times(2)
        .WillRepeatedly(Invoke(
                ReturnImmediate([=](auto in __unused, auto& out) {
                SET_OUT_HEADER_LEN(out, entry);
                out.body.entry.attr.mode = S_IFREG | 0644;
                out.body.entry.nodeid = file_ino;
                out.body.entry.attr.nlink = 1;
                out.body.entry.attr_valid = UINT64_MAX;
                out.body.entry.entry_valid = UINT64_MAX;
        })));
        expect_forget(dir_ino, 1);

        /* Access the file to cache its name */
        ASSERT_EQ(0, access(FULLFPATH, F_OK)) << strerror(errno);
        
        /* Reclaim the directory, invalidating its children from namecache */
        reclaim_vnode(FULLDPATH);

        /* Access the file again, causing another lookup */
        ASSERT_EQ(0, access(FULLFPATH, F_OK)) << strerror(errno);
}

/*
 * Reclaiming the root inode should not send a FUSE_FORGET request, nor should
 * it interfere with further lookup operations.
 */
TEST_F(Forget, root)
{
        const char FULLPATH[] = "mountpoint/some_file.txt";
        const char RELPATH[] = "some_file.txt";
        uint64_t ino = 42;
        mode_t mode = S_IFREG | 0755;

        EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
        .WillRepeatedly(Invoke(
                ReturnImmediate([=](auto in __unused, auto& out) {
                SET_OUT_HEADER_LEN(out, entry);
                out.body.entry.attr.mode = mode;
                out.body.entry.nodeid = ino;
                out.body.entry.attr.nlink = 1;
                out.body.entry.attr_valid = UINT64_MAX;
                out.body.entry.entry_valid = UINT64_MAX;
        })));

        /* access(2) the file to force a lookup. */
        ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);

        reclaim_vnode("mountpoint");
        nap();

        /* Access it again, to make sure it's still possible. */
        ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}