/* SPDX-License-Identifier: LGPL-2.1-or-later */

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

#include "sd-id128.h"
#include "sd-journal.h"

#include "alloc-util.h"
#include "chattr-util.h"
#include "iovec-util.h"
#include "journal-file-util.h"
#include "journal-vacuum.h"
#include "log.h"
#include "logs-show.h"
#include "parse-util.h"
#include "random-util.h"
#include "rm-rf.h"
#include "tests.h"

/* This program tests skipping around in a multi-file journal. */

static bool arg_keep = false;
static dual_timestamp previous_ts = {};

_noreturn_ static void log_assert_errno(const char *text, int error, const char *file, unsigned line, const char *func) {
        log_internal(LOG_CRIT, error, file, line, func,
                     "'%s' failed at %s:%u (%s): %m", text, file, line, func);
        abort();
}

#define assert_ret(expr)                                                \
        do {                                                            \
                int _r_ = (expr);                                       \
                if (_unlikely_(_r_ < 0))                                \
                        log_assert_errno(#expr, -_r_, PROJECT_FILE, __LINE__, __func__); \
        } while (false)

static JournalFile *test_open_internal(const char *name, JournalFileFlags flags) {
        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
        JournalFile *f;

        m = mmap_cache_new();
        assert_se(m != NULL);

        assert_ret(journal_file_open(-1, name, O_RDWR|O_CREAT, flags, 0644, UINT64_MAX, NULL, m, NULL, &f));
        return f;
}

static JournalFile *test_open(const char *name) {
        return test_open_internal(name, JOURNAL_COMPRESS);
}

static JournalFile *test_open_strict(const char *name) {
        return test_open_internal(name, JOURNAL_COMPRESS | JOURNAL_STRICT_ORDER);
}

static void test_close(JournalFile *f) {
        (void) journal_file_offline_close(f);
}

static void test_done(const char *t) {
        log_info("Done...");

        if (arg_keep)
                log_info("Not removing %s", t);
        else {
                journal_directory_vacuum(".", 3000000, 0, 0, NULL, true);

                assert_se(rm_rf(t, REMOVE_ROOT|REMOVE_PHYSICAL) >= 0);
        }

        log_info("------------------------------------------------------------");
}

static void append_number(JournalFile *f, int n, const sd_id128_t *boot_id, uint64_t *seqnum, uint64_t *ret_offset) {
        _cleanup_free_ char *p = NULL, *q = NULL;
        dual_timestamp ts;
        struct iovec iovec[2];
        size_t n_iov = 0;

        dual_timestamp_now(&ts);

        if (ts.monotonic <= previous_ts.monotonic)
                ts.monotonic = previous_ts.monotonic + 1;

        if (ts.realtime <= previous_ts.realtime)
                ts.realtime = previous_ts.realtime + 1;

        previous_ts = ts;

        assert_se(asprintf(&p, "NUMBER=%d", n) >= 0);
        iovec[n_iov++] = IOVEC_MAKE_STRING(p);

        if (boot_id) {
                assert_se(q = strjoin("_BOOT_ID=", SD_ID128_TO_STRING(*boot_id)));
                iovec[n_iov++] = IOVEC_MAKE_STRING(q);
        }

        assert_ret(journal_file_append_entry(f, &ts, boot_id, iovec, n_iov, seqnum, NULL, NULL, ret_offset));
}

static void append_unreferenced_data(JournalFile *f, const sd_id128_t *boot_id) {
        _cleanup_free_ char *q = NULL;
        dual_timestamp ts;
        struct iovec iovec;

        assert(boot_id);

        ts.monotonic = usec_sub_unsigned(previous_ts.monotonic, 10);
        ts.realtime = usec_sub_unsigned(previous_ts.realtime, 10);

        assert_se(q = strjoin("_BOOT_ID=", SD_ID128_TO_STRING(*boot_id)));
        iovec = IOVEC_MAKE_STRING(q);

        assert_se(journal_file_append_entry(f, &ts, boot_id, &iovec, 1, NULL, NULL, NULL, NULL) == -EREMCHG);
}

static void test_check_number(sd_journal *j, int n) {
        sd_id128_t boot_id;
        const void *d;
        _cleanup_free_ char *k = NULL;
        size_t l;
        int x;

        assert_se(sd_journal_get_monotonic_usec(j, NULL, &boot_id) >= 0);
        assert_ret(sd_journal_get_data(j, "NUMBER", &d, &l));
        assert_se(k = strndup(d, l));
        printf("%s %s (expected=%i)\n", SD_ID128_TO_STRING(boot_id), k, n);

        assert_se(safe_atoi(k + STRLEN("NUMBER="), &x) >= 0);
        assert_se(n == x);
}

static void test_check_numbers_down(sd_journal *j, int count) {
        int i;

        for (i = 1; i <= count; i++) {
                int r;
                test_check_number(j, i);
                assert_ret(r = sd_journal_next(j));
                if (i == count)
                        assert_se(r == 0);
                else
                        assert_se(r == 1);
        }

}

static void test_check_numbers_up(sd_journal *j, int count) {
        for (int i = count; i >= 1; i--) {
                int r;
                test_check_number(j, i);
                assert_ret(r = sd_journal_previous(j));
                if (i == 1)
                        assert_se(r == 0);
                else
                        assert_se(r == 1);
        }

}

static void setup_sequential(void) {
        JournalFile *f1, *f2, *f3;
        sd_id128_t id;

        f1 = test_open("one.journal");
        f2 = test_open("two.journal");
        f3 = test_open("three.journal");
        assert_se(sd_id128_randomize(&id) >= 0);
        log_info("boot_id: %s", SD_ID128_TO_STRING(id));
        append_number(f1, 1, &id, NULL, NULL);
        append_number(f1, 2, &id, NULL, NULL);
        append_number(f1, 3, &id, NULL, NULL);
        append_number(f2, 4, &id, NULL, NULL);
        assert_se(sd_id128_randomize(&id) >= 0);
        log_info("boot_id: %s", SD_ID128_TO_STRING(id));
        append_number(f2, 5, &id, NULL, NULL);
        append_number(f2, 6, &id, NULL, NULL);
        append_number(f3, 7, &id, NULL, NULL);
        append_number(f3, 8, &id, NULL, NULL);
        assert_se(sd_id128_randomize(&id) >= 0);
        log_info("boot_id: %s", SD_ID128_TO_STRING(id));
        append_number(f3, 9, &id, NULL, NULL);
        test_close(f1);
        test_close(f2);
        test_close(f3);
}

static void setup_interleaved(void) {
        JournalFile *f1, *f2, *f3;
        sd_id128_t id;

        f1 = test_open("one.journal");
        f2 = test_open("two.journal");
        f3 = test_open("three.journal");
        assert_se(sd_id128_randomize(&id) >= 0);
        log_info("boot_id: %s", SD_ID128_TO_STRING(id));
        append_number(f1, 1, &id, NULL, NULL);
        append_number(f2, 2, &id, NULL, NULL);
        append_number(f3, 3, &id, NULL, NULL);
        append_number(f1, 4, &id, NULL, NULL);
        append_number(f2, 5, &id, NULL, NULL);
        append_number(f3, 6, &id, NULL, NULL);
        append_number(f1, 7, &id, NULL, NULL);
        append_number(f2, 8, &id, NULL, NULL);
        append_number(f3, 9, &id, NULL, NULL);
        test_close(f1);
        test_close(f2);
        test_close(f3);
}

static void setup_unreferenced_data(void) {
        JournalFile *f1, *f2, *f3;
        sd_id128_t id;

        /* For issue #29275. */

        f1 = test_open_strict("one.journal");
        f2 = test_open_strict("two.journal");
        f3 = test_open_strict("three.journal");
        assert_se(sd_id128_randomize(&id) >= 0);
        log_info("boot_id: %s", SD_ID128_TO_STRING(id));
        append_number(f1, 1, &id, NULL, NULL);
        append_number(f1, 2, &id, NULL, NULL);
        append_number(f1, 3, &id, NULL, NULL);
        assert_se(sd_id128_randomize(&id) >= 0);
        log_info("boot_id: %s", SD_ID128_TO_STRING(id));
        append_unreferenced_data(f1, &id);
        append_number(f2, 4, &id, NULL, NULL);
        append_number(f2, 5, &id, NULL, NULL);
        append_number(f2, 6, &id, NULL, NULL);
        assert_se(sd_id128_randomize(&id) >= 0);
        log_info("boot_id: %s", SD_ID128_TO_STRING(id));
        append_unreferenced_data(f2, &id);
        append_number(f3, 7, &id, NULL, NULL);
        append_number(f3, 8, &id, NULL, NULL);
        append_number(f3, 9, &id, NULL, NULL);
        test_close(f1);
        test_close(f2);
        test_close(f3);
}

static void mkdtemp_chdir_chattr(char *path) {
        assert_se(mkdtemp(path));
        assert_se(chdir(path) >= 0);

        /* Speed up things a bit on btrfs, ensuring that CoW is turned off for all files created in our
         * directory during the test run */
        (void) chattr_path(path, FS_NOCOW_FL, FS_NOCOW_FL, NULL);
}

static void test_skip_one(void (*setup)(void)) {
        char t[] = "/var/tmp/journal-skip-XXXXXX";
        sd_journal *j;
        int r;

        mkdtemp_chdir_chattr(t);

        setup();

        /* Seek to head, iterate down. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_next(j) == 1);     /* pointing to the first entry */
        test_check_numbers_down(j, 9);
        sd_journal_close(j);

        /* Seek to head, iterate down. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_next(j) == 1);     /* pointing to the first entry */
        assert_se(sd_journal_previous(j) == 0); /* no-op */
        test_check_numbers_down(j, 9);
        sd_journal_close(j);

        /* Seek to head twice, iterate down. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_next(j) == 1);     /* pointing to the first entry */
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_next(j) == 1);     /* pointing to the first entry */
        test_check_numbers_down(j, 9);
        sd_journal_close(j);

        /* Seek to head, move to previous, then iterate down. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_previous(j) == 0); /* no-op */
        assert_se(sd_journal_next(j) == 1);     /* pointing to the first entry */
        test_check_numbers_down(j, 9);
        sd_journal_close(j);

        /* Seek to head, walk several steps, then iterate down. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_previous(j) == 0); /* no-op */
        assert_se(sd_journal_previous(j) == 0); /* no-op */
        assert_se(sd_journal_previous(j) == 0); /* no-op */
        assert_se(sd_journal_next(j) == 1);     /* pointing to the first entry */
        assert_se(sd_journal_previous(j) == 0); /* no-op */
        assert_se(sd_journal_previous(j) == 0); /* no-op */
        test_check_numbers_down(j, 9);
        sd_journal_close(j);

        /* Seek to tail, iterate up. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_tail(j));
        assert_se(sd_journal_previous(j) == 1); /* pointing to the last entry */
        test_check_numbers_up(j, 9);
        sd_journal_close(j);

        /* Seek to tail twice, iterate up. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_tail(j));
        assert_se(sd_journal_previous(j) == 1); /* pointing to the last entry */
        assert_ret(sd_journal_seek_tail(j));
        assert_se(sd_journal_previous(j) == 1); /* pointing to the last entry */
        test_check_numbers_up(j, 9);
        sd_journal_close(j);

        /* Seek to tail, move to next, then iterate up. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_tail(j));
        assert_se(sd_journal_next(j) == 0);     /* no-op */
        assert_se(sd_journal_previous(j) == 1); /* pointing to the last entry */
        test_check_numbers_up(j, 9);
        sd_journal_close(j);

        /* Seek to tail, walk several steps, then iterate up. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_tail(j));
        assert_se(sd_journal_next(j) == 0);     /* no-op */
        assert_se(sd_journal_next(j) == 0);     /* no-op */
        assert_se(sd_journal_next(j) == 0);     /* no-op */
        assert_se(sd_journal_previous(j) == 1); /* pointing to the last entry. */
        assert_se(sd_journal_next(j) == 0);     /* no-op */
        assert_se(sd_journal_next(j) == 0);     /* no-op */
        test_check_numbers_up(j, 9);
        sd_journal_close(j);

        /* Seek to tail, skip to head, iterate down. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_tail(j));
        assert_se(sd_journal_previous_skip(j, 9) == 9); /* pointing to the first entry. */
        test_check_numbers_down(j, 9);
        sd_journal_close(j);

        /* Seek to tail, skip to head in a more complex way, then iterate down. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_tail(j));
        assert_se(sd_journal_next(j) == 0);
        assert_se(sd_journal_previous_skip(j, 4) == 4);
        assert_se(sd_journal_previous_skip(j, 5) == 5);
        assert_se(sd_journal_previous(j) == 0);
        assert_se(sd_journal_previous_skip(j, 5) == 0);
        assert_se(sd_journal_next(j) == 1);
        assert_se(sd_journal_previous_skip(j, 5) == 1);
        assert_se(sd_journal_next(j) == 1);
        assert_se(sd_journal_next(j) == 1);
        assert_se(sd_journal_previous(j) == 1);
        assert_se(sd_journal_next(j) == 1);
        assert_se(sd_journal_next(j) == 1);
        assert_se(sd_journal_previous_skip(j, 5) == 3);
        test_check_numbers_down(j, 9);
        sd_journal_close(j);

        /* Seek to head, skip to tail, iterate up. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_next_skip(j, 9) == 9);
        test_check_numbers_up(j, 9);
        sd_journal_close(j);

        /* Seek to head, skip to tail in a more complex way, then iterate up. */
        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_ret(sd_journal_seek_head(j));
        assert_se(sd_journal_previous(j) == 0);
        assert_se(sd_journal_next_skip(j, 4) == 4);
        assert_se(sd_journal_next_skip(j, 5) == 5);
        assert_se(sd_journal_next(j) == 0);
        assert_se(sd_journal_next_skip(j, 5) == 0);
        assert_se(sd_journal_previous(j) == 1);
        assert_se(sd_journal_next_skip(j, 5) == 1);
        assert_se(sd_journal_previous(j) == 1);
        assert_se(sd_journal_previous(j) == 1);
        assert_se(sd_journal_next(j) == 1);
        assert_se(sd_journal_previous(j) == 1);
        assert_se(sd_journal_previous(j) == 1);
        assert_se(r = sd_journal_next_skip(j, 5) == 3);
        test_check_numbers_up(j, 9);
        sd_journal_close(j);

        test_done(t);
}

TEST(skip) {
        test_skip_one(setup_sequential);
        test_skip_one(setup_interleaved);
}

static void test_boot_id_one(void (*setup)(void), size_t n_boots_expected) {
        char t[] = "/var/tmp/journal-boot-id-XXXXXX";
        sd_journal *j;
        _cleanup_free_ BootId *boots = NULL;
        size_t n_boots;

        mkdtemp_chdir_chattr(t);

        setup();

        assert_ret(sd_journal_open_directory(&j, t, 0));
        assert_se(journal_get_boots(j, &boots, &n_boots) >= 0);
        assert_se(boots);
        assert_se(n_boots == n_boots_expected);
        sd_journal_close(j);

        FOREACH_ARRAY(b, boots, n_boots) {
                assert_ret(sd_journal_open_directory(&j, t, 0));
                assert_se(journal_find_boot_by_id(j, b->id) == 1);
                sd_journal_close(j);
        }

        for (int i = - (int) n_boots + 1; i <= (int) n_boots; i++) {
                sd_id128_t id;

                assert_ret(sd_journal_open_directory(&j, t, 0));
                assert_se(journal_find_boot_by_offset(j, i, &id) == 1);
                if (i <= 0)
                        assert_se(sd_id128_equal(id, boots[n_boots + i - 1].id));
                else
                        assert_se(sd_id128_equal(id, boots[i - 1].id));
                sd_journal_close(j);
        }

        test_done(t);
}

TEST(boot_id) {
        test_boot_id_one(setup_sequential, 3);
        test_boot_id_one(setup_unreferenced_data, 3);
}

static void test_sequence_numbers_one(void) {
        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
        char t[] = "/var/tmp/journal-seq-XXXXXX";
        JournalFile *one, *two;
        uint64_t seqnum = 0;
        sd_id128_t seqnum_id;

        m = mmap_cache_new();
        assert_se(m != NULL);

        mkdtemp_chdir_chattr(t);

        assert_se(journal_file_open(-1, "one.journal", O_RDWR|O_CREAT, JOURNAL_COMPRESS, 0644,
                                    UINT64_MAX, NULL, m, NULL, &one) == 0);

        append_number(one, 1, NULL, &seqnum, NULL);
        printf("seqnum=%"PRIu64"\n", seqnum);
        assert_se(seqnum == 1);
        append_number(one, 2, NULL, &seqnum, NULL);
        printf("seqnum=%"PRIu64"\n", seqnum);
        assert_se(seqnum == 2);

        assert_se(one->header->state == STATE_ONLINE);
        assert_se(!sd_id128_equal(one->header->file_id, one->header->machine_id));
        assert_se(!sd_id128_equal(one->header->file_id, one->header->tail_entry_boot_id));
        assert_se(sd_id128_equal(one->header->file_id, one->header->seqnum_id));

        memcpy(&seqnum_id, &one->header->seqnum_id, sizeof(sd_id128_t));

        assert_se(journal_file_open(-1, "two.journal", O_RDWR|O_CREAT, JOURNAL_COMPRESS, 0644,
                                    UINT64_MAX, NULL, m, one, &two) == 0);

        assert_se(two->header->state == STATE_ONLINE);
        assert_se(!sd_id128_equal(two->header->file_id, one->header->file_id));
        assert_se(sd_id128_equal(two->header->machine_id, one->header->machine_id));
        assert_se(sd_id128_is_null(two->header->tail_entry_boot_id)); /* Not written yet. */
        assert_se(sd_id128_equal(two->header->seqnum_id, one->header->seqnum_id));

        append_number(two, 3, NULL, &seqnum, NULL);
        printf("seqnum=%"PRIu64"\n", seqnum);
        assert_se(seqnum == 3);
        append_number(two, 4, NULL, &seqnum, NULL);
        printf("seqnum=%"PRIu64"\n", seqnum);
        assert_se(seqnum == 4);

        /* Verify tail_entry_boot_id. */
        assert_se(sd_id128_equal(two->header->tail_entry_boot_id, one->header->tail_entry_boot_id));

        test_close(two);

        append_number(one, 5, NULL, &seqnum, NULL);
        printf("seqnum=%"PRIu64"\n", seqnum);
        assert_se(seqnum == 5);

        append_number(one, 6, NULL, &seqnum, NULL);
        printf("seqnum=%"PRIu64"\n", seqnum);
        assert_se(seqnum == 6);

        test_close(one);

        /* If the machine-id is not initialized, the header file verification
         * (which happens when re-opening a journal file) will fail. */
        if (sd_id128_get_machine(NULL) >= 0) {
                /* restart server */
                seqnum = 0;

                assert_se(journal_file_open(-1, "two.journal", O_RDWR, JOURNAL_COMPRESS, 0,
                                            UINT64_MAX, NULL, m, NULL, &two) == 0);

                assert_se(sd_id128_equal(two->header->seqnum_id, seqnum_id));

                append_number(two, 7, NULL, &seqnum, NULL);
                printf("seqnum=%"PRIu64"\n", seqnum);
                assert_se(seqnum == 5);

                /* So..., here we have the same seqnum in two files with the
                 * same seqnum_id. */

                test_close(two);
        }

        test_done(t);
}

TEST(sequence_numbers) {
        assert_se(setenv("SYSTEMD_JOURNAL_COMPACT", "0", 1) >= 0);
        test_sequence_numbers_one();

        assert_se(setenv("SYSTEMD_JOURNAL_COMPACT", "1", 1) >= 0);
        test_sequence_numbers_one();
}

static int expected_result(uint64_t needle, const uint64_t *candidates, const uint64_t *offset, size_t n, direction_t direction, uint64_t *ret) {
        switch (direction) {
        case DIRECTION_DOWN:
                for (size_t i = 0; i < n; i++) {
                        if (candidates[i] == 0) {
                                *ret = 0;
                                return 0;
                        }
                        if (needle <= candidates[i]) {
                                *ret = offset[i];
                                return 1;
                        }
                }
                *ret = 0;
                return 0;

        case DIRECTION_UP:
                for (size_t i = 0; i < n; i++)
                        if (needle < candidates[i] || candidates[i] == 0) {
                                if (i == 0) {
                                        *ret = 0;
                                        return 0;
                                }
                                *ret = offset[i - 1];
                                return 1;
                        }
                *ret = offset[n - 1];
                return 1;

        default:
                assert_not_reached();
        }
}

static void verify(JournalFile *f, const uint64_t *seqnum, const uint64_t *offset, size_t n) {
        uint64_t p, q;
        int r, e;

        /* by seqnum (sequential) */
        for (uint64_t i = 0; i < n + 2; i++) {
                p = 0;
                r = journal_file_move_to_entry_by_seqnum(f, i, DIRECTION_DOWN, NULL, &p);
                e = expected_result(i, seqnum, offset, n, DIRECTION_DOWN, &q);
                assert_se(r == e);
                assert_se(p == q);

                p = 0;
                r = journal_file_move_to_entry_by_seqnum(f, i, DIRECTION_UP, NULL, &p);
                e = expected_result(i, seqnum, offset, n, DIRECTION_UP, &q);
                assert_se(r == e);
                assert_se(p == q);
        }

        /* by seqnum (random) */
        for (size_t trial = 0; trial < 3 * n; trial++) {
                uint64_t i = random_u64_range(n + 2);

                p = 0;
                r = journal_file_move_to_entry_by_seqnum(f, i, DIRECTION_DOWN, NULL, &p);
                e = expected_result(i, seqnum, offset, n, DIRECTION_DOWN, &q);
                assert_se(r == e);
                assert_se(p == q);
        }
        for (size_t trial = 0; trial < 3 * n; trial++) {
                uint64_t i = random_u64_range(n + 2);

                p = 0;
                r = journal_file_move_to_entry_by_seqnum(f, i, DIRECTION_UP, NULL, &p);
                e = expected_result(i, seqnum, offset, n, DIRECTION_UP, &q);
                assert_se(r == e);
                assert_se(p == q);
        }

        /* by offset (sequential) */
        for (size_t i = 0; i < n; i++) {
                p = 0;
                r = journal_file_move_to_entry_by_offset(f, offset[i] - 1, DIRECTION_DOWN, NULL, &p);
                e = expected_result(offset[i] - 1, offset, offset, n, DIRECTION_DOWN, &q);
                assert_se(r == e);
                assert_se(p == q);

                p = 0;
                r = journal_file_move_to_entry_by_offset(f, offset[i], DIRECTION_DOWN, NULL, &p);
                e = expected_result(offset[i], offset, offset, n, DIRECTION_DOWN, &q);
                assert_se(r == e);
                assert_se(p == q);

                p = 0;
                r = journal_file_move_to_entry_by_offset(f, offset[i] + 1, DIRECTION_DOWN, NULL, &p);
                e = expected_result(offset[i] + 1, offset, offset, n, DIRECTION_DOWN, &q);
                assert_se(r == e);
                assert_se(p == q);

                p = 0;
                r = journal_file_move_to_entry_by_offset(f, offset[i] - 1, DIRECTION_UP, NULL, &p);
                e = expected_result(offset[i] - 1, offset, offset, n, DIRECTION_UP, &q);
                assert_se(r == e);
                assert_se(p == q);

                p = 0;
                r = journal_file_move_to_entry_by_offset(f, offset[i], DIRECTION_UP, NULL, &p);
                e = expected_result(offset[i], offset, offset, n, DIRECTION_UP, &q);
                assert_se(r == e);
                assert_se(p == q);

                p = 0;
                r = journal_file_move_to_entry_by_offset(f, offset[i] + 1, DIRECTION_UP, NULL, &p);
                e = expected_result(offset[i] + 1, offset, offset, n, DIRECTION_UP, &q);
                assert_se(r == e);
                assert_se(p == q);
        }

        /* by offset (random) */
        for (size_t trial = 0; trial < 3 * n; trial++) {
                uint64_t i = offset[0] - 1 + random_u64_range(offset[n-1] - offset[0] + 2);

                p = 0;
                r = journal_file_move_to_entry_by_offset(f, i, DIRECTION_DOWN, NULL, &p);
                e = expected_result(i, offset, offset, n, DIRECTION_DOWN, &q);
                assert_se(r == e);
                assert_se(p == q);
        }
        for (size_t trial = 0; trial < 3 * n; trial++) {
                uint64_t i = offset[0] - 1 + random_u64_range(offset[n-1] - offset[0] + 2);

                p = 0;
                r = journal_file_move_to_entry_by_offset(f, i, DIRECTION_UP, NULL, &p);
                e = expected_result(i, offset, offset, n, DIRECTION_UP, &q);
                assert_se(r == e);
                assert_se(p == q);
        }
}

static void test_generic_array_bisect_one(size_t n, size_t num_corrupted) {
        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
        char t[] = "/var/tmp/journal-seq-XXXXXX";
        _cleanup_free_ uint64_t *seqnum = NULL, *offset = NULL;
        JournalFile *f;

        log_info("/* %s(%zu, %zu) */", __func__, n, num_corrupted);

        assert_se(m = mmap_cache_new());

        mkdtemp_chdir_chattr(t);

        assert_se(journal_file_open(-1, "test.journal", O_RDWR|O_CREAT, JOURNAL_COMPRESS, 0644,
                                    UINT64_MAX, NULL, m, NULL, &f) == 0);

        assert_se(seqnum = new0(uint64_t, n));
        assert_se(offset = new0(uint64_t, n));

        for (size_t i = 0; i < n; i++) {
                append_number(f, i, NULL, seqnum + i, offset + i);
                if (i == 0) {
                        assert_se(seqnum[i] > 0);
                        assert_se(offset[i] > 0);
                } else {
                        assert_se(seqnum[i] > seqnum[i-1]);
                        assert_se(offset[i] > offset[i-1]);
                }
        }

        verify(f, seqnum, offset, n);

        /* Reset chain cache. */
        assert_se(journal_file_move_to_entry_by_offset(f, offset[0], DIRECTION_DOWN, NULL, NULL) > 0);

        /* make journal corrupted by clearing seqnum. */
        for (size_t i = n - num_corrupted; i < n; i++) {
                Object *o;

                assert_se(journal_file_move_to_object(f, OBJECT_ENTRY, offset[i], &o) >= 0);
                assert_se(o);
                o->entry.seqnum = 0;
                seqnum[i] = 0;
        }

        verify(f, seqnum, offset, n);

        test_close(f);
        test_done(t);
}

TEST(generic_array_bisect) {
        for (size_t n = 1; n < 10; n++)
                for (size_t m = 1; m <= n; m++)
                        test_generic_array_bisect_one(n, m);

        test_generic_array_bisect_one(100, 40);
}

static int intro(void) {
        /* journal_file_open() requires a valid machine id */
        if (access("/etc/machine-id", F_OK) != 0)
                return log_tests_skipped("/etc/machine-id not found");

        arg_keep = saved_argc > 1;

        return EXIT_SUCCESS;
}

DEFINE_TEST_MAIN_WITH_INTRO(LOG_DEBUG, intro);