// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2023 Red Hat
 */

#include "config.h"

#include "logger.h"
#include "memory-alloc.h"
#include "numeric.h"
#include "string-utils.h"
#include "thread-utils.h"

static const u8 INDEX_CONFIG_MAGIC[] = "ALBIC";
static const u8 INDEX_CONFIG_VERSION_6_02[] = "06.02";
static const u8 INDEX_CONFIG_VERSION_8_02[] = "08.02";

#define DEFAULT_VOLUME_READ_THREADS 2
#define MAX_VOLUME_READ_THREADS 16
#define INDEX_CONFIG_MAGIC_LENGTH (sizeof(INDEX_CONFIG_MAGIC) - 1)
#define INDEX_CONFIG_VERSION_LENGTH ((int)(sizeof(INDEX_CONFIG_VERSION_6_02) - 1))

static bool is_version(const u8 *version, u8 *buffer)
{
        return memcmp(version, buffer, INDEX_CONFIG_VERSION_LENGTH) == 0;
}

static bool are_matching_configurations(struct uds_configuration *saved_config,
                                        struct index_geometry *saved_geometry,
                                        struct uds_configuration *user)
{
        struct index_geometry *geometry = user->geometry;
        bool result = true;

        if (saved_geometry->record_pages_per_chapter != geometry->record_pages_per_chapter) {
                vdo_log_error("Record pages per chapter (%u) does not match (%u)",
                              saved_geometry->record_pages_per_chapter,
                              geometry->record_pages_per_chapter);
                result = false;
        }

        if (saved_geometry->chapters_per_volume != geometry->chapters_per_volume) {
                vdo_log_error("Chapter count (%u) does not match (%u)",
                              saved_geometry->chapters_per_volume,
                              geometry->chapters_per_volume);
                result = false;
        }

        if (saved_geometry->sparse_chapters_per_volume != geometry->sparse_chapters_per_volume) {
                vdo_log_error("Sparse chapter count (%u) does not match (%u)",
                              saved_geometry->sparse_chapters_per_volume,
                              geometry->sparse_chapters_per_volume);
                result = false;
        }

        if (saved_config->cache_chapters != user->cache_chapters) {
                vdo_log_error("Cache size (%u) does not match (%u)",
                              saved_config->cache_chapters, user->cache_chapters);
                result = false;
        }

        if (saved_config->volume_index_mean_delta != user->volume_index_mean_delta) {
                vdo_log_error("Volume index mean delta (%u) does not match (%u)",
                              saved_config->volume_index_mean_delta,
                              user->volume_index_mean_delta);
                result = false;
        }

        if (saved_geometry->bytes_per_page != geometry->bytes_per_page) {
                vdo_log_error("Bytes per page value (%zu) does not match (%zu)",
                              saved_geometry->bytes_per_page, geometry->bytes_per_page);
                result = false;
        }

        if (saved_config->sparse_sample_rate != user->sparse_sample_rate) {
                vdo_log_error("Sparse sample rate (%u) does not match (%u)",
                              saved_config->sparse_sample_rate,
                              user->sparse_sample_rate);
                result = false;
        }

        if (saved_config->nonce != user->nonce) {
                vdo_log_error("Nonce (%llu) does not match (%llu)",
                              (unsigned long long) saved_config->nonce,
                              (unsigned long long) user->nonce);
                result = false;
        }

        return result;
}

/* Read the configuration and validate it against the provided one. */
int uds_validate_config_contents(struct buffered_reader *reader,
                                 struct uds_configuration *user_config)
{
        int result;
        struct uds_configuration config;
        struct index_geometry geometry;
        u8 version_buffer[INDEX_CONFIG_VERSION_LENGTH];
        u32 bytes_per_page;
        u8 buffer[sizeof(struct uds_configuration_6_02)];
        size_t offset = 0;

        result = uds_verify_buffered_data(reader, INDEX_CONFIG_MAGIC,
                                          INDEX_CONFIG_MAGIC_LENGTH);
        if (result != UDS_SUCCESS)
                return result;

        result = uds_read_from_buffered_reader(reader, version_buffer,
                                               INDEX_CONFIG_VERSION_LENGTH);
        if (result != UDS_SUCCESS)
                return vdo_log_error_strerror(result, "cannot read index config version");

        if (!is_version(INDEX_CONFIG_VERSION_6_02, version_buffer) &&
            !is_version(INDEX_CONFIG_VERSION_8_02, version_buffer)) {
                return vdo_log_error_strerror(UDS_CORRUPT_DATA,
                                              "unsupported configuration version: '%.*s'",
                                              INDEX_CONFIG_VERSION_LENGTH,
                                              version_buffer);
        }

        result = uds_read_from_buffered_reader(reader, buffer, sizeof(buffer));
        if (result != UDS_SUCCESS)
                return vdo_log_error_strerror(result, "cannot read config data");

        decode_u32_le(buffer, &offset, &geometry.record_pages_per_chapter);
        decode_u32_le(buffer, &offset, &geometry.chapters_per_volume);
        decode_u32_le(buffer, &offset, &geometry.sparse_chapters_per_volume);
        decode_u32_le(buffer, &offset, &config.cache_chapters);
        offset += sizeof(u32);
        decode_u32_le(buffer, &offset, &config.volume_index_mean_delta);
        decode_u32_le(buffer, &offset, &bytes_per_page);
        geometry.bytes_per_page = bytes_per_page;
        decode_u32_le(buffer, &offset, &config.sparse_sample_rate);
        decode_u64_le(buffer, &offset, &config.nonce);

        result = VDO_ASSERT(offset == sizeof(struct uds_configuration_6_02),
                            "%zu bytes read but not decoded",
                            sizeof(struct uds_configuration_6_02) - offset);
        if (result != VDO_SUCCESS)
                return UDS_CORRUPT_DATA;

        if (is_version(INDEX_CONFIG_VERSION_6_02, version_buffer)) {
                user_config->geometry->remapped_virtual = 0;
                user_config->geometry->remapped_physical = 0;
        } else {
                u8 remapping[sizeof(u64) + sizeof(u64)];

                result = uds_read_from_buffered_reader(reader, remapping,
                                                       sizeof(remapping));
                if (result != UDS_SUCCESS)
                        return vdo_log_error_strerror(result, "cannot read converted config");

                offset = 0;
                decode_u64_le(remapping, &offset,
                              &user_config->geometry->remapped_virtual);
                decode_u64_le(remapping, &offset,
                              &user_config->geometry->remapped_physical);
        }

        if (!are_matching_configurations(&config, &geometry, user_config)) {
                vdo_log_warning("Supplied configuration does not match save");
                return UDS_NO_INDEX;
        }

        return UDS_SUCCESS;
}

/*
 * Write the configuration to stable storage. If the superblock version is < 4, write the 6.02
 * version; otherwise write the 8.02 version, indicating the configuration is for an index that has
 * been reduced by one chapter.
 */
int uds_write_config_contents(struct buffered_writer *writer,
                              struct uds_configuration *config, u32 version)
{
        int result;
        struct index_geometry *geometry = config->geometry;
        u8 buffer[sizeof(struct uds_configuration_8_02)];
        size_t offset = 0;

        result = uds_write_to_buffered_writer(writer, INDEX_CONFIG_MAGIC,
                                              INDEX_CONFIG_MAGIC_LENGTH);
        if (result != UDS_SUCCESS)
                return result;

        /*
         * If version is < 4, the index has not been reduced by a chapter so it must be written out
         * as version 6.02 so that it is still compatible with older versions of UDS.
         */
        if (version >= 4) {
                result = uds_write_to_buffered_writer(writer, INDEX_CONFIG_VERSION_8_02,
                                                      INDEX_CONFIG_VERSION_LENGTH);
                if (result != UDS_SUCCESS)
                        return result;
        } else {
                result = uds_write_to_buffered_writer(writer, INDEX_CONFIG_VERSION_6_02,
                                                      INDEX_CONFIG_VERSION_LENGTH);
                if (result != UDS_SUCCESS)
                        return result;
        }

        encode_u32_le(buffer, &offset, geometry->record_pages_per_chapter);
        encode_u32_le(buffer, &offset, geometry->chapters_per_volume);
        encode_u32_le(buffer, &offset, geometry->sparse_chapters_per_volume);
        encode_u32_le(buffer, &offset, config->cache_chapters);
        encode_u32_le(buffer, &offset, 0);
        encode_u32_le(buffer, &offset, config->volume_index_mean_delta);
        encode_u32_le(buffer, &offset, geometry->bytes_per_page);
        encode_u32_le(buffer, &offset, config->sparse_sample_rate);
        encode_u64_le(buffer, &offset, config->nonce);

        result = VDO_ASSERT(offset == sizeof(struct uds_configuration_6_02),
                            "%zu bytes encoded, of %zu expected", offset,
                            sizeof(struct uds_configuration_6_02));
        if (result != VDO_SUCCESS)
                return result;

        if (version >= 4) {
                encode_u64_le(buffer, &offset, geometry->remapped_virtual);
                encode_u64_le(buffer, &offset, geometry->remapped_physical);
        }

        return uds_write_to_buffered_writer(writer, buffer, offset);
}

/* Compute configuration parameters that depend on memory size. */
static int compute_memory_sizes(uds_memory_config_size_t mem_gb, bool sparse,
                                u32 *chapters_per_volume, u32 *record_pages_per_chapter,
                                u32 *sparse_chapters_per_volume)
{
        u32 reduced_chapters = 0;
        u32 base_chapters;

        if (mem_gb == UDS_MEMORY_CONFIG_256MB) {
                base_chapters = DEFAULT_CHAPTERS_PER_VOLUME;
                *record_pages_per_chapter = SMALL_RECORD_PAGES_PER_CHAPTER;
        } else if (mem_gb == UDS_MEMORY_CONFIG_512MB) {
                base_chapters = DEFAULT_CHAPTERS_PER_VOLUME;
                *record_pages_per_chapter = 2 * SMALL_RECORD_PAGES_PER_CHAPTER;
        } else if (mem_gb == UDS_MEMORY_CONFIG_768MB) {
                base_chapters = DEFAULT_CHAPTERS_PER_VOLUME;
                *record_pages_per_chapter = 3 * SMALL_RECORD_PAGES_PER_CHAPTER;
        } else if ((mem_gb >= 1) && (mem_gb <= UDS_MEMORY_CONFIG_MAX)) {
                base_chapters = mem_gb * DEFAULT_CHAPTERS_PER_VOLUME;
                *record_pages_per_chapter = DEFAULT_RECORD_PAGES_PER_CHAPTER;
        } else if (mem_gb == UDS_MEMORY_CONFIG_REDUCED_256MB) {
                reduced_chapters = 1;
                base_chapters = DEFAULT_CHAPTERS_PER_VOLUME;
                *record_pages_per_chapter = SMALL_RECORD_PAGES_PER_CHAPTER;
        } else if (mem_gb == UDS_MEMORY_CONFIG_REDUCED_512MB) {
                reduced_chapters = 1;
                base_chapters = DEFAULT_CHAPTERS_PER_VOLUME;
                *record_pages_per_chapter = 2 * SMALL_RECORD_PAGES_PER_CHAPTER;
        } else if (mem_gb == UDS_MEMORY_CONFIG_REDUCED_768MB) {
                reduced_chapters = 1;
                base_chapters = DEFAULT_CHAPTERS_PER_VOLUME;
                *record_pages_per_chapter = 3 * SMALL_RECORD_PAGES_PER_CHAPTER;
        } else if ((mem_gb >= 1 + UDS_MEMORY_CONFIG_REDUCED) &&
                   (mem_gb <= UDS_MEMORY_CONFIG_REDUCED_MAX)) {
                reduced_chapters = 1;
                base_chapters = ((mem_gb - UDS_MEMORY_CONFIG_REDUCED) *
                                 DEFAULT_CHAPTERS_PER_VOLUME);
                *record_pages_per_chapter = DEFAULT_RECORD_PAGES_PER_CHAPTER;
        } else {
                vdo_log_error("received invalid memory size");
                return -EINVAL;
        }

        if (sparse) {
                /* Make 95% of chapters sparse, allowing 10x more records. */
                *sparse_chapters_per_volume = (19 * base_chapters) / 2;
                base_chapters *= 10;
        } else {
                *sparse_chapters_per_volume = 0;
        }

        *chapters_per_volume = base_chapters - reduced_chapters;
        return UDS_SUCCESS;
}

static unsigned int __must_check normalize_zone_count(unsigned int requested)
{
        unsigned int zone_count = requested;

        if (zone_count == 0)
                zone_count = num_online_cpus() / 2;

        if (zone_count < 1)
                zone_count = 1;

        if (zone_count > MAX_ZONES)
                zone_count = MAX_ZONES;

        vdo_log_info("Using %u indexing zone%s for concurrency.",
                     zone_count, zone_count == 1 ? "" : "s");
        return zone_count;
}

static unsigned int __must_check normalize_read_threads(unsigned int requested)
{
        unsigned int read_threads = requested;

        if (read_threads < 1)
                read_threads = DEFAULT_VOLUME_READ_THREADS;

        if (read_threads > MAX_VOLUME_READ_THREADS)
                read_threads = MAX_VOLUME_READ_THREADS;

        return read_threads;
}

int uds_make_configuration(const struct uds_parameters *params,
                           struct uds_configuration **config_ptr)
{
        struct uds_configuration *config;
        u32 chapters_per_volume = 0;
        u32 record_pages_per_chapter = 0;
        u32 sparse_chapters_per_volume = 0;
        int result;

        result = compute_memory_sizes(params->memory_size, params->sparse,
                                      &chapters_per_volume, &record_pages_per_chapter,
                                      &sparse_chapters_per_volume);
        if (result != UDS_SUCCESS)
                return result;

        result = vdo_allocate(1, struct uds_configuration, __func__, &config);
        if (result != VDO_SUCCESS)
                return result;

        result = uds_make_index_geometry(DEFAULT_BYTES_PER_PAGE, record_pages_per_chapter,
                                         chapters_per_volume, sparse_chapters_per_volume,
                                         0, 0, &config->geometry);
        if (result != UDS_SUCCESS) {
                uds_free_configuration(config);
                return result;
        }

        config->zone_count = normalize_zone_count(params->zone_count);
        config->read_threads = normalize_read_threads(params->read_threads);

        config->cache_chapters = DEFAULT_CACHE_CHAPTERS;
        config->volume_index_mean_delta = DEFAULT_VOLUME_INDEX_MEAN_DELTA;
        config->sparse_sample_rate = (params->sparse ? DEFAULT_SPARSE_SAMPLE_RATE : 0);
        config->nonce = params->nonce;
        config->bdev = params->bdev;
        config->offset = params->offset;
        config->size = params->size;

        *config_ptr = config;
        return UDS_SUCCESS;
}

void uds_free_configuration(struct uds_configuration *config)
{
        if (config != NULL) {
                uds_free_index_geometry(config->geometry);
                vdo_free(config);
        }
}

void uds_log_configuration(struct uds_configuration *config)
{
        struct index_geometry *geometry = config->geometry;

        vdo_log_debug("Configuration:");
        vdo_log_debug("  Record pages per chapter:   %10u", geometry->record_pages_per_chapter);
        vdo_log_debug("  Chapters per volume:        %10u", geometry->chapters_per_volume);
        vdo_log_debug("  Sparse chapters per volume: %10u", geometry->sparse_chapters_per_volume);
        vdo_log_debug("  Cache size (chapters):      %10u", config->cache_chapters);
        vdo_log_debug("  Volume index mean delta:    %10u", config->volume_index_mean_delta);
        vdo_log_debug("  Bytes per page:             %10zu", geometry->bytes_per_page);
        vdo_log_debug("  Sparse sample rate:         %10u", config->sparse_sample_rate);
        vdo_log_debug("  Nonce:                      %llu", (unsigned long long) config->nonce);
}