/*-
 * 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/mman.h>

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

#include <iomanip>

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

/* 
 * For testing I/O like fsx does, but deterministically and without a real
 * underlying file system
 */

using namespace testing;

const char FULLPATH[] = "mountpoint/some_file.txt";
const char RELPATH[] = "some_file.txt";
const uint64_t ino = 42;

static void compare(const void *tbuf, const void *controlbuf, off_t baseofs,
        ssize_t size)
{
        int i;

        for (i = 0; i < size; i++) {
                if (((const char*)tbuf)[i] != ((const char*)controlbuf)[i]) {
                        off_t ofs = baseofs + i;
                        FAIL() << "miscompare at offset "
                               << std::hex
                               << std::showbase
                               << ofs
                               << ".  expected = "
                               << std::setw(2)
                               << (unsigned)((const uint8_t*)controlbuf)[i]
                               << " got = "
                               << (unsigned)((const uint8_t*)tbuf)[i];
                }
        }
}

typedef tuple<bool, uint32_t, cache_mode, uint32_t> IoParam;

class Io: public FuseTest, public WithParamInterface<IoParam> {
public:
int m_backing_fd, m_control_fd, m_test_fd;
off_t m_filesize;
bool m_direct_io;

Io(): m_backing_fd(-1), m_control_fd(-1), m_test_fd(-1), m_filesize(0),
        m_direct_io(false) {};

void SetUp()
{
        m_backing_fd = open("backing_file", O_RDWR | O_CREAT | O_TRUNC, 0644);
        if (m_backing_fd < 0)
                FAIL() << strerror(errno);
        m_control_fd = open("control", O_RDWR | O_CREAT | O_TRUNC, 0644);
        if (m_control_fd < 0)
                FAIL() << strerror(errno);
        srandom(22'9'1982);     // Seed with my birthday

        if (get<0>(GetParam()))
                m_init_flags |= FUSE_ASYNC_READ;
        m_maxwrite = get<1>(GetParam());
        switch (get<2>(GetParam())) {
                case Uncached:
                        m_direct_io = true;
                        break;
                case WritebackAsync:
                        m_async = true;
                        /* FALLTHROUGH */
                case Writeback:
                        m_init_flags |= FUSE_WRITEBACK_CACHE;
                        /* FALLTHROUGH */
                case Writethrough:
                        break;
                default:
                        FAIL() << "Unknown cache mode";
        }
        m_kernel_minor_version = get<3>(GetParam());
        m_noatime = true;       // To prevent SETATTR for atime on close

        FuseTest::SetUp();
        if (IsSkipped())
                return;

        if (verbosity > 0) {
                printf("Test Parameters: init_flags=%#x maxwrite=%#x "
                    "%sasync cache=%s kernel_minor_version=%d\n",
                    m_init_flags, m_maxwrite, m_async? "" : "no",
                    cache_mode_to_s(get<2>(GetParam())),
                    m_kernel_minor_version);
        }

        expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
        expect_open(ino, m_direct_io ? FOPEN_DIRECT_IO : 0, 1);
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_WRITE &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillRepeatedly(Invoke(ReturnImmediate([=](auto in, auto& out) {
                const char *buf = (const char*)in.body.bytes +
                        sizeof(struct fuse_write_in);
                ssize_t isize = in.body.write.size;
                off_t iofs = in.body.write.offset;

                assert((size_t)isize <= sizeof(in.body.bytes) -
                        sizeof(struct fuse_write_in));
                ASSERT_EQ(isize, pwrite(m_backing_fd, buf, isize, iofs))
                        << strerror(errno);
                SET_OUT_HEADER_LEN(out, write);
                out.body.write.size = isize;
        })));
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_READ &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillRepeatedly(Invoke(ReturnImmediate([=](auto in, auto& out) {
                ssize_t isize = in.body.write.size;
                off_t iofs = in.body.write.offset;
                void *buf = out.body.bytes;
                ssize_t osize;

                assert((size_t)isize <= sizeof(out.body.bytes));
                osize = pread(m_backing_fd, buf, isize, iofs);
                ASSERT_LE(0, osize) << strerror(errno);
                out.header.len = sizeof(struct fuse_out_header) + osize;
        })));
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_SETATTR &&
                                in.header.nodeid == ino &&
                                (in.body.setattr.valid & FATTR_SIZE));
                                
                }, Eq(true)),
                _)
        ).WillRepeatedly(Invoke(ReturnImmediate([=](auto in, auto& out) {
                ASSERT_EQ(0, ftruncate(m_backing_fd, in.body.setattr.size))
                        << strerror(errno);
                SET_OUT_HEADER_LEN(out, attr);
                out.body.attr.attr.ino = ino;
                out.body.attr.attr.mode = S_IFREG | 0755;
                out.body.attr.attr.size = in.body.setattr.size;
                out.body.attr.attr_valid = UINT64_MAX;
        })));
        /* Any test that close()s will send FUSE_FLUSH and FUSE_RELEASE */
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_FLUSH &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillRepeatedly(Invoke(ReturnErrno(0)));
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_RELEASE &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillRepeatedly(Invoke(ReturnErrno(0)));
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_COPY_FILE_RANGE &&
                                in.header.nodeid == ino &&
                                in.body.copy_file_range.nodeid_out == ino &&
                                in.body.copy_file_range.flags == 0);
                }, Eq(true)),
                _)
        ).WillRepeatedly(Invoke(ReturnImmediate([=](auto in, auto& out) {
                off_t off_in = in.body.copy_file_range.off_in;
                off_t off_out = in.body.copy_file_range.off_out;
                ASSERT_EQ((ssize_t)in.body.copy_file_range.len,
                    copy_file_range(m_backing_fd, &off_in, m_backing_fd,
                            &off_out, in.body.copy_file_range.len, 0));
                SET_OUT_HEADER_LEN(out, write);
                out.body.write.size = in.body.copy_file_range.len;
        })));
        /* Claim that we don't support FUSE_LSEEK */
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_LSEEK);
                }, Eq(true)),
                _)
        ).WillRepeatedly(Invoke(ReturnErrno(ENOSYS)));

        m_test_fd = open(FULLPATH, O_RDWR );
        EXPECT_LE(0, m_test_fd) << strerror(errno);
}

void TearDown()
{
        if (m_test_fd >= 0)
                close(m_test_fd);
        if (m_backing_fd >= 0)
                close(m_backing_fd);
        if (m_control_fd >= 0)
                close(m_control_fd);
        FuseTest::TearDown();
        leak(m_test_fd);
}

void do_closeopen()
{
        ASSERT_EQ(0, close(m_test_fd)) << strerror(errno);
        m_test_fd = open("backing_file", O_RDWR);
        ASSERT_LE(0, m_test_fd) << strerror(errno);

        ASSERT_EQ(0, close(m_control_fd)) << strerror(errno);
        m_control_fd = open("control", O_RDWR);
        ASSERT_LE(0, m_control_fd) << strerror(errno);
}

void do_copy_file_range(off_t off_in, off_t off_out, size_t size)
{
        ssize_t r;
        off_t test_off_in = off_in;
        off_t test_off_out = off_out;
        off_t test_size = size;
        off_t control_off_in = off_in;
        off_t control_off_out = off_out;
        off_t control_size = size;

        while (test_size > 0) {
                r = copy_file_range(m_test_fd, &test_off_in, m_test_fd,
                                &test_off_out, test_size, 0);
                ASSERT_GT(r, 0) << strerror(errno);
                test_size -= r;
        }
        while (control_size > 0) {
                r = copy_file_range(m_control_fd, &control_off_in, m_control_fd,
                                &control_off_out, control_size, 0);
                ASSERT_GT(r, 0) << strerror(errno);
                control_size -= r;
        }
        m_filesize = std::max(m_filesize, off_out + (off_t)size);
}

void do_ftruncate(off_t offs)
{
        ASSERT_EQ(0, ftruncate(m_test_fd, offs)) << strerror(errno);
        ASSERT_EQ(0, ftruncate(m_control_fd, offs)) << strerror(errno);
        m_filesize = offs;
}

void do_mapread(off_t offs, ssize_t size)
{
        char *control_buf;
        void *p;
        off_t pg_offset, page_mask;
        size_t map_size;

        page_mask = getpagesize() - 1;
        pg_offset = offs & page_mask;
        map_size = pg_offset + size;

        p = mmap(NULL, map_size, PROT_READ, MAP_FILE | MAP_SHARED, m_test_fd,
            offs - pg_offset);
        ASSERT_NE(p, MAP_FAILED) << strerror(errno);

        control_buf = new char[size];

        ASSERT_EQ(size, pread(m_control_fd, control_buf, size, offs))
                << strerror(errno);

        compare((void*)((char*)p + pg_offset), control_buf, offs, size);

        ASSERT_EQ(0, munmap(p, map_size)) << strerror(errno);
        delete[] control_buf;
}

void do_read(off_t offs, ssize_t size)
{
        char *test_buf, *control_buf;
        ssize_t r;

        test_buf = new char[size];
        control_buf = new char[size];

        errno = 0;
        r = pread(m_test_fd, test_buf, size, offs);
        ASSERT_NE(-1, r) << strerror(errno);
        ASSERT_EQ(size, r) << "unexpected short read";
        r = pread(m_control_fd, control_buf, size, offs);
        ASSERT_NE(-1, r) << strerror(errno);
        ASSERT_EQ(size, r) << "unexpected short read";

        compare(test_buf, control_buf, offs, size);

        delete[] control_buf;
        delete[] test_buf;
}

void do_mapwrite(off_t offs, ssize_t size)
{
        char *buf;
        void *p;
        off_t pg_offset, page_mask;
        size_t map_size;
        long i;

        page_mask = getpagesize() - 1;
        pg_offset = offs & page_mask;
        map_size = pg_offset + size;

        buf = new char[size];
        for (i=0; i < size; i++)
                buf[i] = random();

        if (offs + size > m_filesize) {
                /* 
                 * Must manually extend.  vm_mmap_vnode will not implicitly
                 * extend a vnode
                 */
                do_ftruncate(offs + size);
        }

        p = mmap(NULL, map_size, PROT_READ | PROT_WRITE,
            MAP_FILE | MAP_SHARED, m_test_fd, offs - pg_offset);
        ASSERT_NE(p, MAP_FAILED) << strerror(errno);

        bcopy(buf, (char*)p + pg_offset, size);
        ASSERT_EQ(size, pwrite(m_control_fd, buf, size, offs))
                << strerror(errno);

        delete[] buf;
        ASSERT_EQ(0, munmap(p, map_size)) << strerror(errno);
}

void do_write(off_t offs, ssize_t size)
{
        char *buf;
        long i;

        buf = new char[size];
        for (i=0; i < size; i++)
                buf[i] = random();

        ASSERT_EQ(size, pwrite(m_test_fd, buf, size, offs ))
                << strerror(errno);
        ASSERT_EQ(size, pwrite(m_control_fd, buf, size, offs))
                << strerror(errno);
        m_filesize = std::max(m_filesize, offs + size);

        delete[] buf;
}

};

class IoCacheable: public Io {
public:
virtual void SetUp() {
        Io::SetUp();
}
};

class IoCopyFileRange: public Io {
public:
virtual void SetUp() {
        Io::SetUp();
}
};

/*
 * Extend a file with dirty data in the last page of the last block.
 *
 * fsx -WR -P /tmp -S8 -N3 fsx.bin
 */
TEST_P(Io, extend_from_dirty_page)
{
        off_t wofs = 0x21a0;
        ssize_t wsize = 0xf0a8;
        off_t rofs = 0xb284;
        ssize_t rsize = 0x9b22;
        off_t truncsize = 0x28702;

        do_write(wofs, wsize);
        do_ftruncate(truncsize);
        do_read(rofs, rsize);
}

/*
 * mapwrite into a newly extended part of a file.
 *
 * fsx -c 100 -i 100 -l 524288 -o 131072 -N5 -P /tmp -S19 fsx.bin
 */
TEST_P(IoCacheable, extend_by_mapwrite)
{
        do_mapwrite(0x29a3a, 0x849e);   /* [0x29a3a, 0x31ed7] */
        do_mapwrite(0x3c7d8, 0x3994);   /* [0x3c7d8, 0x4016b] */
        do_read(0x30c16, 0xf556);       /* [0x30c16, 0x4016b] */
}

/*
 * When writing the last page of a file, it must be written synchronously.
 * Otherwise the cached page can become invalid by a subsequent extend
 * operation.
 *
 * fsx -WR -P /tmp -S642 -N3 fsx.bin
 */
TEST_P(Io, last_page)
{
        do_write(0x1134f, 0xcc77);      /* [0x1134f, 0x1dfc5] */
        do_write(0x2096a, 0xdfa7);      /* [0x2096a, 0x2e910] */
        do_read(0x1a3aa, 0xb5b7);       /* [0x1a3aa, 0x25960] */
}

/*
 * Read a hole using mmap
 *
 * fsx -c 100 -i 100 -l 524288 -o 131072 -N11 -P /tmp  -S14 fsx.bin
 */
TEST_P(IoCacheable, mapread_hole)
{
        do_write(0xf205, 0x123b7);      /* [0xf205, 0x215bb] */
        do_mapread(0x2f4c, 0xeeea);     /* [0x2f4c, 0x11e35] */
}

/* 
 * Read a hole from a block that contains some cached data.
 *
 * fsx -WR -P /tmp -S55  fsx.bin
 */
TEST_P(Io, read_hole_from_cached_block)
{
        off_t wofs = 0x160c5;
        ssize_t wsize = 0xa996;
        off_t rofs = 0x472e;
        ssize_t rsize = 0xd8d5;

        do_write(wofs, wsize);
        do_read(rofs, rsize);
}

/*
 * Truncating a file into a dirty buffer should not causing anything untoward
 * to happen when that buffer is eventually flushed.
 *
 * fsx -WR -P /tmp -S839 -d -N6 fsx.bin
 */
TEST_P(Io, truncate_into_dirty_buffer)
{
        off_t wofs0 = 0x3bad7;
        ssize_t wsize0 = 0x4529;
        off_t wofs1 = 0xc30d;
        ssize_t wsize1 = 0x5f77;
        off_t truncsize0 = 0x10916;
        off_t rofs = 0xdf17;
        ssize_t rsize = 0x29ff;
        off_t truncsize1 = 0x152b4;

        do_write(wofs0, wsize0);
        do_write(wofs1, wsize1);
        do_ftruncate(truncsize0);
        do_read(rofs, rsize);
        do_ftruncate(truncsize1);
        close(m_test_fd);
}

/*
 * Truncating a file into a dirty buffer should not causing anything untoward
 * to happen when that buffer is eventually flushed, even when the buffer's
 * dirty_off is > 0.
 *
 * Based on this command with a few steps removed:
 * fsx -WR -P /tmp -S677 -d -N8 fsx.bin
 */
TEST_P(Io, truncate_into_dirty_buffer2)
{
        off_t truncsize0 = 0x344f3;
        off_t wofs = 0x2790c;
        ssize_t wsize = 0xd86a;
        off_t truncsize1 = 0x2de38;
        off_t rofs2 = 0x1fd7a;
        ssize_t rsize2 = 0xc594;
        off_t truncsize2 = 0x31e71;

        /* Sets the file size to something larger than the next write */
        do_ftruncate(truncsize0);
        /* 
         * Creates a dirty buffer.  The part in lbn 2 doesn't flush
         * synchronously.
         */
        do_write(wofs, wsize);
        /* Truncates part of the dirty buffer created in step 2 */
        do_ftruncate(truncsize1);
        /* XXX ?I don't know why this is necessary? */
        do_read(rofs2, rsize2);
        /* Truncates the dirty buffer */
        do_ftruncate(truncsize2);
        close(m_test_fd);
}

/*
 * Regression test for a bug introduced in r348931
 *
 * Sequence of operations:
 * 1) The first write reads lbn so it can modify it
 * 2) The first write flushes lbn 3 immediately because it's the end of file
 * 3) The first write then flushes lbn 4 because it's the end of the file
 * 4) The second write modifies the cached versions of lbn 3 and 4
 * 5) The third write's getblkx invalidates lbn 4's B_CACHE because it's
 *    extending the buffer.  Then it flushes lbn 4 because B_DELWRI was set but
 *    B_CACHE was clear.
 * 6) fuse_write_biobackend erroneously called vfs_bio_clrbuf, putting the
 *    buffer into a weird write-only state.  All read operations would return
 *    0.  Writes were apparently still processed, because the buffer's contents
 *    were correct when examined in a core dump.
 * 7) The third write reads lbn 4 because cache is clear
 * 9) uiomove dutifully copies new data into the buffer
 * 10) The buffer's dirty is flushed to lbn 4
 * 11) The read returns all zeros because of step 6.
 *
 * Based on:
 * fsx -WR -l 524388 -o 131072 -P /tmp -S6456 -q  fsx.bin
 */
TEST_P(Io, resize_a_valid_buffer_while_extending)
{
        do_write(0x36ee6, 0x14530);     /* [0x36ee6, 0x4b415] */
        do_write(0x33256, 0x1507c);     /* [0x33256, 0x482d1] */
        do_write(0x4c03d, 0x175c);      /* [0x4c03d, 0x4d798] */
        do_read(0x3599c, 0xe277);       /* [0x3599c, 0x43c12] */
        close(m_test_fd);
}

/*
 * mmap of a suitable region could trigger a panic.  I'm not sure what
 * combination of size and offset counts as "suitable".  Regression test for
 * https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=276191
 */
TEST_P(IoCacheable, vnode_pager_generic_putpage_clean_block_at_eof)
{
        do_mapwrite(0x3b4e0, 0x1bbc3);
}

/*
 * A copy_file_range that follows an mmap write to the input area needs to
 * flush the mmap buffer first.
 */
TEST_P(IoCopyFileRange, copy_file_range_from_mapped_write)
{
        do_mapwrite(0, 0x1000);
        do_copy_file_range(0, 0x1000, 0x1000);
        do_read(0x1000, 0x1000);
}


INSTANTIATE_TEST_SUITE_P(Io, Io,
        Combine(Bool(),                                 /* async read */
                Values(0x1000, 0x10000, 0x20000),       /* m_maxwrite */
                Values(Uncached, Writethrough, Writeback, WritebackAsync),
                Values(28)                              /* kernel_minor_vers */
        )
);

INSTANTIATE_TEST_SUITE_P(Io, IoCacheable,
        Combine(Bool(),                                 /* async read */
                Values(0x1000, 0x10000, 0x20000),       /* m_maxwrite */
                Values(Writethrough, Writeback, WritebackAsync),
                Values(28)                              /* kernel_minor_vers */
        )
);

INSTANTIATE_TEST_SUITE_P(Io, IoCopyFileRange,
        Combine(Values(true),                           /* async read */
                Values(0x10000),                        /* m_maxwrite */
                Values(Writethrough, Writeback, WritebackAsync),
                Values(27, 28)                          /* kernel_minor_vers */
        )
);