/*-
 * 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 <dirent.h>
#include <fcntl.h>
}

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

using namespace testing;
using namespace std;

class Readdir: public FuseTest {
public:
void expect_lookup(const char *relpath, uint64_t ino)
{
        FuseTest::expect_lookup(relpath, ino, S_IFDIR | 0755, 0, 1);
}
};

class Readdir_7_8: public Readdir {
public:
virtual void SetUp() {
        m_kernel_minor_version = 8;
        Readdir::SetUp();
}

void expect_lookup(const char *relpath, uint64_t ino)
{
        FuseTest::expect_lookup_7_8(relpath, ino, S_IFDIR | 0755, 0, 1);
}
};

const char dot[] = ".";
const char dotdot[] = "..";

/* FUSE_READDIR returns nothing but "." and ".." */
TEST_F(Readdir, dots)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        DIR *dir;
        struct dirent *de;
        vector<struct dirent> ents(2);
        vector<struct dirent> empty_ents(0);

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);
        ents[0].d_fileno = 2;
        ents[0].d_off = 2000;
        ents[0].d_namlen = sizeof(dotdot);
        ents[0].d_type = DT_DIR;
        strncpy(ents[0].d_name, dotdot, ents[0].d_namlen);
        ents[1].d_fileno = 3;
        ents[1].d_off = 3000;
        ents[1].d_namlen = sizeof(dot);
        ents[1].d_type = DT_DIR;
        strncpy(ents[1].d_name, dot, ents[1].d_namlen);
        expect_readdir(ino, 0, ents);
        expect_readdir(ino, 3000, empty_ents);

        errno = 0;
        dir = opendir(FULLPATH);
        ASSERT_NE(nullptr, dir) << strerror(errno);

        errno = 0;
        de = readdir(dir);
        ASSERT_NE(nullptr, de) << strerror(errno);
        EXPECT_EQ(2ul, de->d_fileno);
        EXPECT_EQ(DT_DIR, de->d_type);
        EXPECT_EQ(sizeof(dotdot), de->d_namlen);
        EXPECT_EQ(0, strcmp(dotdot, de->d_name));

        errno = 0;
        de = readdir(dir);
        ASSERT_NE(nullptr, de) << strerror(errno);
        EXPECT_EQ(3ul, de->d_fileno);
        EXPECT_EQ(DT_DIR, de->d_type);
        EXPECT_EQ(sizeof(dot), de->d_namlen);
        EXPECT_EQ(0, strcmp(dot, de->d_name));

        ASSERT_EQ(nullptr, readdir(dir));
        ASSERT_EQ(0, errno);

        leakdir(dir);
}

TEST_F(Readdir, eio)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        DIR *dir;
        struct dirent *de;

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);
        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_READDIR &&
                                in.header.nodeid == ino &&
                                in.body.readdir.offset == 0);
                }, Eq(true)),
                _)
        ).WillOnce(Invoke(ReturnErrno(EIO)));

        errno = 0;
        dir = opendir(FULLPATH);
        ASSERT_NE(nullptr, dir) << strerror(errno);

        errno = 0;
        de = readdir(dir);
        ASSERT_EQ(nullptr, de);
        ASSERT_EQ(EIO, errno);

        leakdir(dir);
}

/*
 * getdirentries(2) can use a larger buffer size than readdir(3).  It also has
 * some additional non-standardized fields in the returned dirent.
 */
TEST_F(Readdir, getdirentries_empty)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        int fd;
        char buf[8192];
        ssize_t r;

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);

        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_READDIR &&
                                in.header.nodeid == ino &&
                                in.body.readdir.size == 8192);
                }, Eq(true)),
                _)
        ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
                out.header.error = 0;
                out.header.len = sizeof(out.header);
        })));

        fd = open(FULLPATH, O_DIRECTORY);
        ASSERT_LE(0, fd) << strerror(errno);
        r = getdirentries(fd, buf, sizeof(buf), 0);
        ASSERT_EQ(0, r) << strerror(errno);

        leak(fd);
}

/*
 * The dirent.d_off field can be used with lseek to position the directory so
 * that getdirentries will return the subsequent dirent.
 */
TEST_F(Readdir, getdirentries_seek)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        vector<struct dirent> ents0(2);
        vector<struct dirent> ents1(1);
        uint64_t ino = 42;
        int fd;
        const size_t bufsize = 8192;
        char buf[bufsize];
        struct dirent *de0, *de1;
        ssize_t r;

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);

        ents0[0].d_fileno = 2;
        ents0[0].d_off = 2000;
        ents0[0].d_namlen = sizeof(dotdot);
        ents0[0].d_type = DT_DIR;
        strncpy(ents0[0].d_name, dotdot, ents0[0].d_namlen);
        expect_readdir(ino, 0, ents0);
        ents0[1].d_fileno = 3;
        ents0[1].d_off = 3000;
        ents0[1].d_namlen = sizeof(dot);
        ents0[1].d_type = DT_DIR;
        ents1[0].d_fileno = 3;
        ents1[0].d_off = 3000;
        ents1[0].d_namlen = sizeof(dot);
        ents1[0].d_type = DT_DIR;
        strncpy(ents1[0].d_name, dot, ents1[0].d_namlen);
        expect_readdir(ino, 0, ents0);
        expect_readdir(ino, 2000, ents1);

        fd = open(FULLPATH, O_DIRECTORY);
        ASSERT_LE(0, fd) << strerror(errno);
        r = getdirentries(fd, buf, sizeof(buf), 0);
        ASSERT_LT(0, r) << strerror(errno);
        de0 = (struct dirent*)&buf[0];
        ASSERT_EQ(2000, de0->d_off);
        ASSERT_LT(de0->d_reclen + offsetof(struct dirent, d_fileno), bufsize);
        de1 = (struct dirent*)(&(buf[de0->d_reclen]));
        ASSERT_EQ(3ul, de1->d_fileno);

        r = lseek(fd, de0->d_off, SEEK_SET);
        ASSERT_LE(0, r);
        r = getdirentries(fd, buf, sizeof(buf), 0);
        ASSERT_LT(0, r) << strerror(errno);
        de0 = (struct dirent*)&buf[0];
        ASSERT_EQ(3000, de0->d_off);
}

/* 
 * Nothing bad should happen if getdirentries is called on two file descriptors
 * which were concurrently open, but one has already been closed.
 * This is a regression test for a specific bug dating from r238402.
 */
TEST_F(Readdir, getdirentries_concurrent)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        int fd0, fd1;
        char buf[8192];
        ssize_t r;

        FuseTest::expect_lookup(RELPATH, ino, S_IFDIR | 0755, 0, 2);
        expect_opendir(ino);

        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_READDIR &&
                                in.header.nodeid == ino &&
                                in.body.readdir.size == 8192);
                }, Eq(true)),
                _)
        ).Times(2)
        .WillRepeatedly(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
                out.header.error = 0;
                out.header.len = sizeof(out.header);
        })));

        fd0 = open(FULLPATH, O_DIRECTORY);
        ASSERT_LE(0, fd0) << strerror(errno);

        fd1 = open(FULLPATH, O_DIRECTORY);
        ASSERT_LE(0, fd1) << strerror(errno);

        r = getdirentries(fd0, buf, sizeof(buf), 0);
        ASSERT_EQ(0, r) << strerror(errno);

        EXPECT_EQ(0, close(fd0)) << strerror(errno);

        r = getdirentries(fd1, buf, sizeof(buf), 0);
        ASSERT_EQ(0, r) << strerror(errno);

        leak(fd0);
        leak(fd1);
}

/*
 * FUSE_READDIR returns nothing, not even "." and "..".  This is legal, though
 * the filesystem obviously won't be fully functional.
 */
TEST_F(Readdir, nodots)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        DIR *dir;

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);

        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_READDIR &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
                out.header.error = 0;
                out.header.len = sizeof(out.header);
        })));

        errno = 0;
        dir = opendir(FULLPATH);
        ASSERT_NE(nullptr, dir) << strerror(errno);
        errno = 0;
        ASSERT_EQ(nullptr, readdir(dir));
        ASSERT_EQ(0, errno);

        leakdir(dir);
}

/*
 * FUSE_READDIR returns a path with an embedded NUL. Obviously illegal, but
 * nothing bad should happen.
 */
TEST_F(Readdir, nul)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        DIR *dir;
        struct dirent *de;
        vector<struct dirent> ents(1);
        vector<struct dirent> empty_ents(0);
        const char nul[] = "foo\0bar";

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);
        ents[0].d_fileno = 4;
        ents[0].d_off = 4000;
        ents[0].d_namlen = sizeof(nul);
        ents[0].d_type = DT_REG;
        strncpy(ents[0].d_name, nul, ents[0].d_namlen);
        expect_readdir(ino, 0, ents);
        expect_readdir(ino, 4000, empty_ents);

        errno = 0;
        dir = opendir(FULLPATH);
        ASSERT_NE(nullptr, dir) << strerror(errno);

        errno = 0;
        de = readdir(dir);
        ASSERT_NE(nullptr, de) << strerror(errno);
        EXPECT_EQ(4ul, de->d_fileno);
        EXPECT_EQ(DT_REG, de->d_type);
        EXPECT_EQ(sizeof(nul), de->d_namlen);
        EXPECT_EQ(0, strcmp(nul, de->d_name));

        ASSERT_EQ(nullptr, readdir(dir));
        ASSERT_EQ(0, errno);

        leakdir(dir);
}


/* telldir(3) and seekdir(3) should work with fuse */
TEST_F(Readdir, seekdir)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        DIR *dir;
        struct dirent *de;
        /*
         * use enough entries to be > 4096 bytes, so getdirentries must be
         * called
         * multiple times.
         */
        vector<struct dirent> ents0(122), ents1(102), ents2(30);
        long bookmark;
        int i = 0;

        for (auto& it: ents0) {
                snprintf(it.d_name, MAXNAMLEN, "file.%d", i);
                it.d_fileno = 2 + i;
                it.d_off = (2 + i) * 1000;
                it.d_namlen = strlen(it.d_name);
                it.d_type = DT_REG;
                i++;
        }
        for (auto& it: ents1) {
                snprintf(it.d_name, MAXNAMLEN, "file.%d", i);
                it.d_fileno = 2 + i;
                it.d_off = (2 + i) * 1000;
                it.d_namlen = strlen(it.d_name);
                it.d_type = DT_REG;
                i++;
        }
        for (auto& it: ents2) {
                snprintf(it.d_name, MAXNAMLEN, "file.%d", i);
                it.d_fileno = 2 + i;
                it.d_off = (2 + i) * 1000;
                it.d_namlen = strlen(it.d_name);
                it.d_type = DT_REG;
                i++;
        }

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);

        expect_readdir(ino, 0, ents0);
        expect_readdir(ino, 123000, ents1);
        expect_readdir(ino, 225000, ents2);

        errno = 0;
        dir = opendir(FULLPATH);
        ASSERT_NE(nullptr, dir) << strerror(errno);

        for (i=0; i < 128; i++) {
                errno = 0;
                de = readdir(dir);
                ASSERT_NE(nullptr, de) << strerror(errno);
                EXPECT_EQ(2 + (ino_t)i, de->d_fileno);
        }
        bookmark = telldir(dir);

        for (; i < 232; i++) {
                errno = 0;
                de = readdir(dir);
                ASSERT_NE(nullptr, de) << strerror(errno);
                EXPECT_EQ(2 + (ino_t)i, de->d_fileno);
        }

        seekdir(dir, bookmark);
        de = readdir(dir);
        ASSERT_NE(nullptr, de) << strerror(errno);
        EXPECT_EQ(130ul, de->d_fileno);

        leakdir(dir);
}

/*
 * FUSE_READDIR returns a path with an embedded /. Obviously illegal, but
 * nothing bad should happen.
 */
TEST_F(Readdir, slash)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        DIR *dir;
        struct dirent *de;
        vector<struct dirent> ents(1);
        vector<struct dirent> empty_ents(0);
        const char foobar[] = "foo/bar";

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);
        ents[0].d_fileno = 4;
        ents[0].d_off = 4000;
        ents[0].d_namlen = sizeof(foobar);
        ents[0].d_type = DT_REG;
        strncpy(ents[0].d_name, foobar, ents[0].d_namlen);
        expect_readdir(ino, 0, ents);
        expect_readdir(ino, 4000, empty_ents);

        errno = 0;
        dir = opendir(FULLPATH);
        ASSERT_NE(nullptr, dir) << strerror(errno);

        errno = 0;
        de = readdir(dir);
        ASSERT_NE(nullptr, de) << strerror(errno);
        EXPECT_EQ(4ul, de->d_fileno);
        EXPECT_EQ(DT_REG, de->d_type);
        EXPECT_EQ(sizeof(foobar), de->d_namlen);
        EXPECT_EQ(0, strcmp(foobar, de->d_name));

        ASSERT_EQ(nullptr, readdir(dir));
        ASSERT_EQ(0, errno);

        leakdir(dir);
}

TEST_F(Readdir_7_8, nodots)
{
        const char FULLPATH[] = "mountpoint/some_dir";
        const char RELPATH[] = "some_dir";
        uint64_t ino = 42;
        DIR *dir;

        expect_lookup(RELPATH, ino);
        expect_opendir(ino);

        EXPECT_CALL(*m_mock, process(
                ResultOf([=](auto in) {
                        return (in.header.opcode == FUSE_READDIR &&
                                in.header.nodeid == ino);
                }, Eq(true)),
                _)
        ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
                out.header.error = 0;
                out.header.len = sizeof(out.header);
        })));

        errno = 0;
        dir = opendir(FULLPATH);
        ASSERT_NE(nullptr, dir) << strerror(errno);
        errno = 0;
        ASSERT_EQ(nullptr, readdir(dir));
        ASSERT_EQ(0, errno);

        leakdir(dir);
}