/*-
 * 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/wait.h>

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

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

using namespace testing;

class Open: public FuseTest {

public:

/* Test an OK open of a file with the given flags */
void test_ok(int os_flags, int fuse_flags) {
        const char FULLPATH[] = "mountpoint/some_file.txt";
        const char RELPATH[] = "some_file.txt";
        uint64_t ino = 42;
        int fd;

        FuseTest::expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_OPEN &&
                                in.body.open.flags == (uint32_t)fuse_flags &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillOnce(Invoke(ReturnImmediate([](auto in __unused, auto& out) {
                out.header.len = sizeof(out.header);
                SET_OUT_HEADER_LEN(out, open);
        })));

        fd = open(FULLPATH, os_flags);
        ASSERT_LE(0, fd) << strerror(errno);
        leak(fd);
}
};

/* 
 * fusefs(4) does not support I/O on device nodes (neither does UFS).  But it
 * shouldn't crash
 */
TEST_F(Open, chr)
{
        const char FULLPATH[] = "mountpoint/zero";
        const char RELPATH[] = "zero";
        uint64_t ino = 42;

        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 = S_IFCHR | 0644;
                out.body.entry.nodeid = ino;
                out.body.entry.attr.nlink = 1;
                out.body.entry.attr_valid = UINT64_MAX;
                out.body.entry.attr.rdev = 44;  /* /dev/zero's rdev */
        })));

        ASSERT_EQ(-1, open(FULLPATH, O_RDONLY));
        EXPECT_EQ(EOPNOTSUPP, errno);
}

/* 
 * The fuse daemon fails the request with enoent.  This usually indicates a
 * race condition: some other FUSE client removed the file in between when the
 * kernel checked for it with lookup and tried to open it
 */
TEST_F(Open, enoent)
{
        const char FULLPATH[] = "mountpoint/some_file.txt";
        const char RELPATH[] = "some_file.txt";
        uint64_t ino = 42;
        sem_t sem;

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

        expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_OPEN &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillOnce(Invoke(ReturnErrno(ENOENT)));
        // Since FUSE_OPEN returns ENOENT, the kernel will reclaim the vnode
        // and send a FUSE_FORGET
        expect_forget(ino, 1, &sem);

        ASSERT_EQ(-1, open(FULLPATH, O_RDONLY));
        EXPECT_EQ(ENOENT, errno);

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

/* 
 * The daemon is responsible for checking file permissions (unless the
 * default_permissions mount option was used)
 */
TEST_F(Open, eperm)
{
        const char FULLPATH[] = "mountpoint/some_file.txt";
        const char RELPATH[] = "some_file.txt";
        uint64_t ino = 42;

        expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_OPEN &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillOnce(Invoke(ReturnErrno(EPERM)));
        ASSERT_EQ(-1, open(FULLPATH, O_RDONLY));
        EXPECT_EQ(EPERM, errno);
}

/* 
 * fusefs must issue multiple FUSE_OPEN operations if clients with different
 * credentials open the same file, even if they use the same mode.  This is
 * necessary so that the daemon can validate each set of credentials.
 */
TEST_F(Open, multiple_creds)
{
        const static char FULLPATH[] = "mountpoint/some_file.txt";
        const static char RELPATH[] = "some_file.txt";
        int fd1, status;
        const static uint64_t ino = 42;
        const static uint64_t fh0 = 100, fh1 = 200;

        /* Fork a child to open the file with different credentials */
        fork(false, &status, [&] {

                expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 2);
                EXPECT_CALL(*m_mock, process(
                        ResultOf([=](auto in) {
                                return (in.header.opcode == FUSE_OPEN &&
                                        in.header.pid == (uint32_t)getpid() &&
                                        in.header.nodeid == ino);
                        }, Eq(true)),
                        _)
                ).WillOnce(Invoke(
                        ReturnImmediate([](auto in __unused, auto& out) {
                        out.body.open.fh = fh0;
                        out.header.len = sizeof(out.header);
                        SET_OUT_HEADER_LEN(out, open);
                })));

                EXPECT_CALL(*m_mock, process(
                        ResultOf([=](auto in) {
                                return (in.header.opcode == FUSE_OPEN &&
                                        in.header.pid != (uint32_t)getpid() &&
                                        in.header.nodeid == ino);
                        }, Eq(true)),
                        _)
                ).WillOnce(Invoke(
                        ReturnImmediate([](auto in __unused, auto& out) {
                        out.body.open.fh = fh1;
                        out.header.len = sizeof(out.header);
                        SET_OUT_HEADER_LEN(out, open);
                })));
                expect_flush(ino, 2, ReturnErrno(0));
                expect_release(ino, fh0);
                expect_release(ino, fh1);

                fd1 = open(FULLPATH, O_RDONLY);
                ASSERT_LE(0, fd1) << strerror(errno);
        }, [] {
                int fd0;

                fd0 = open(FULLPATH, O_RDONLY);
                if (fd0 < 0) {
                        perror("open");
                        return(1);
                }
                leak(fd0);
                return 0;
        }
        );
        ASSERT_EQ(0, WEXITSTATUS(status));

        close(fd1);
}

/* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236340 */
TEST_F(Open, DISABLED_o_append)
{
        test_ok(O_WRONLY | O_APPEND, O_WRONLY | O_APPEND);
}

/* The kernel is supposed to filter out this flag */
TEST_F(Open, o_creat)
{
        test_ok(O_WRONLY | O_CREAT, O_WRONLY);
}

/* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236340 */
TEST_F(Open, DISABLED_o_direct)
{
        test_ok(O_WRONLY | O_DIRECT, O_WRONLY | O_DIRECT);
}

/* The kernel is supposed to filter out this flag */
TEST_F(Open, o_excl)
{
        test_ok(O_WRONLY | O_EXCL, O_WRONLY);
}

TEST_F(Open, o_exec)
{
        test_ok(O_EXEC, O_EXEC);
}

/* The kernel is supposed to filter out this flag */
TEST_F(Open, o_noctty)
{
        test_ok(O_WRONLY | O_NOCTTY, O_WRONLY);
}

TEST_F(Open, o_rdonly)
{
        test_ok(O_RDONLY, O_RDONLY);
}

/* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236340 */
TEST_F(Open, DISABLED_o_trunc)
{
        test_ok(O_WRONLY | O_TRUNC, O_WRONLY | O_TRUNC);
}

TEST_F(Open, o_wronly)
{
        test_ok(O_WRONLY, O_WRONLY);
}

TEST_F(Open, o_rdwr)
{
        test_ok(O_RDWR, O_RDWR);
}

/*
 * If a fuse server returns ENOSYS to a
 * FUSE_OPEN, then it and subsequent FUSE_OPEN and FUSE_RELEASE operations will
 * also succeed automatically without being sent to the server.
 */
TEST_F(Open, enosys)
{
        const char FULLPATH[] = "mountpoint/some_file.txt";
        const char RELPATH[] = "some_file.txt";
        uint64_t ino = 42;
        int fd;

        FuseTest::expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 2);
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_OPEN &&
                                in.body.open.flags == (uint32_t)O_RDONLY &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).Times(1)
        .WillOnce(Invoke(ReturnErrno(ENOSYS)));
        expect_flush(ino, 1, ReturnErrno(ENOSYS));

        fd = open(FULLPATH, O_RDONLY);
        ASSERT_LE(0, fd) << strerror(errno);
        close(fd);

        fd = open(FULLPATH, O_RDONLY);
        ASSERT_LE(0, fd) << strerror(errno);

        leak(fd);
}