HelenOS sources

root/uspace/app/mkfat/mkfat.c

DEFINITIONS

1. main
2. syntax_print
3. fat_label_encode
4. fat_params_compute
5. fat_blocks_write
6. fat_bootsec_create

/*
 * Copyright (c) 2024 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

/** @addtogroup mkfat
 * @{
 */

/**
 * @file        mkfat.c
 * @brief       Tool for creating new FAT file systems.
 *
 * Currently we can create 12/16/32-bit FAT.
 */

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <block.h>
#include <mem.h>
#include <loc.h>
#include <byteorder.h>
#include <inttypes.h>
#include <errno.h>
#include <rndgen.h>
#include <str.h>
#include "fat.h"
#include "fat_dentry.h"

#define NAME    "mkfat"

#define LABEL_NONAME "NO NAME"

/** Divide and round up. */
#define div_round_up(a, b) (((a) + (b) - 1) / (b))

/** Default file-system parameters */
enum {
        default_sector_size             = 512,
        default_sectors_per_cluster     = 4,
        default_fat_count               = 2,
        default_reserved_clusters       = 2,
        default_media_descriptor        = 0xF8 /**< fixed disk */,
        fat32_root_cluster              = 2
};

/** Configurable file-system parameters */
typedef struct fat_cfg {
        int fat_type; /* FAT12 = 12, FAT16 = 16, FAT32 = 32 */
        size_t sector_size;
        uint32_t total_sectors;
        uint16_t root_ent_max;
        uint32_t addt_res_sectors;
        uint8_t sectors_per_cluster;

        uint16_t reserved_sectors;
        uint32_t rootdir_sectors;
        uint32_t fat_sectors;
        uint32_t total_clusters;
        uint8_t fat_count;
        const char *label;
} fat_cfg_t;

static void syntax_print(void);

static errno_t fat_params_compute(struct fat_cfg *cfg);
static errno_t fat_blocks_write(struct fat_cfg const *cfg, service_id_t service_id);
static errno_t fat_bootsec_create(struct fat_cfg const *cfg, struct fat_bs *bs);

int main(int argc, char **argv)
{
        struct fat_cfg cfg;

        errno_t rc;
        char *dev_path;
        service_id_t service_id;
        char *endptr;
        aoff64_t dev_nblocks;

        cfg.sector_size = default_sector_size;
        cfg.sectors_per_cluster = default_sectors_per_cluster;
        cfg.fat_count = default_fat_count;
        cfg.total_sectors = 0;
        cfg.addt_res_sectors = 0;
        cfg.root_ent_max = 128;
        cfg.fat_type = FATAUTO;
        cfg.label = NULL;

        if (argc < 2) {
                printf(NAME ": Error, argument missing.\n");
                syntax_print();
                return 1;
        }

        --argc;
        ++argv;

        while (*argv[0] == '-') {
                if (str_cmp(*argv, "--size") == 0) {
                        --argc;
                        ++argv;
                        if (*argv == NULL) {
                                printf(NAME ": Error, argument missing.\n");
                                syntax_print();
                                return 1;
                        }

                        cfg.total_sectors = strtol(*argv, &endptr, 10);
                        if (*endptr != '\0') {
                                printf(NAME ": Error, invalid argument.\n");
                                syntax_print();
                                return 1;
                        }

                        --argc;
                        ++argv;
                }

                if (str_cmp(*argv, "--type") == 0) {
                        --argc;
                        ++argv;
                        if (*argv == NULL) {
                                printf(NAME ": Error, argument missing.\n");
                                syntax_print();
                                return 1;
                        }

                        cfg.fat_type = strtol(*argv, &endptr, 10);
                        if (*endptr != '\0') {
                                printf(NAME ": Error, invalid argument.\n");
                                syntax_print();
                                return 1;
                        }

                        --argc;
                        ++argv;
                }

                if (str_cmp(*argv, "--label") == 0) {
                        --argc;
                        ++argv;
                        if (*argv == NULL) {
                                printf(NAME ": Error, argument missing.\n");
                                syntax_print();
                                return 1;
                        }

                        cfg.label = *argv;

                        --argc;
                        ++argv;
                }

                if (str_cmp(*argv, "-") == 0) {
                        --argc;
                        ++argv;
                        break;
                }
        }

        if (argc != 1) {
                printf(NAME ": Error, unexpected argument.\n");
                syntax_print();
                return 1;
        }

        dev_path = *argv;
        printf("Device: %s\n", dev_path);

        rc = loc_service_get_id(dev_path, &service_id, 0);
        if (rc != EOK) {
                printf(NAME ": Error resolving device `%s'.\n", dev_path);
                return 2;
        }

        rc = block_init(service_id);
        if (rc != EOK)  {
                printf(NAME ": Error initializing libblock.\n");
                return 2;
        }

        rc = block_get_bsize(service_id, &cfg.sector_size);
        if (rc != EOK) {
                printf(NAME ": Error determining device block size.\n");
                return 2;
        }

        rc = block_get_nblocks(service_id, &dev_nblocks);
        if (rc != EOK) {
                printf(NAME ": Warning, failed to obtain block device size.\n");
        } else {
                printf(NAME ": Block device has %" PRIuOFF64 " blocks.\n",
                    dev_nblocks);
                if (!cfg.total_sectors || dev_nblocks < cfg.total_sectors)
                        cfg.total_sectors = dev_nblocks;
        }

        if (cfg.total_sectors == 0) {
                printf(NAME ": Error. You must specify filesystem size.\n");
                return 1;
        }

        if (cfg.fat_type != FATAUTO && cfg.fat_type != FAT12 && cfg.fat_type != FAT16 &&
            cfg.fat_type != FAT32) {
                printf(NAME ": Error. Unknown FAT type.\n");
                return 2;
        }

        printf(NAME ": Creating FAT filesystem on device %s.\n", dev_path);

        rc = fat_params_compute(&cfg);
        if (rc != EOK) {
                printf(NAME ": Invalid file-system parameters.\n");
                return 2;
        }

        printf(NAME ": Filesystem type FAT%d.\n", cfg.fat_type);

        rc = fat_blocks_write(&cfg, service_id);
        if (rc != EOK) {
                printf(NAME ": Error writing device.\n");
                return 2;
        }

        block_fini(service_id);
        printf("Success.\n");

        return 0;
}

static void syntax_print(void)
{
        printf("syntax: mkfat [<options>...] <device_name>\n");
        printf("options:\n"
            "\t--size <sectors> Filesystem size, overrides device size\n"
            "\t--type 12|16|32  FAT type (auto-detected by default)\n"
            "\t--label <label>  Volume label\n");
}

static errno_t fat_label_encode(void *dest, const char *src)
{
        int i;
        const char *sp;
        uint8_t *dp;

        i = 0;
        sp = src;
        dp = (uint8_t *)dest;

        while (*sp != '\0' && i < FAT_VOLLABEL_LEN) {
                if (!ascii_check(*sp))
                        return EINVAL;
                if (dp != NULL)
                        dp[i] = toupper(*sp);
                ++i;
                ++sp;
        }

        while (i < FAT_VOLLABEL_LEN) {
                if (dp != NULL)
                        dp[i] = FAT_PAD;
                ++i;
        }

        return EOK;
}

/** Derive sizes of different filesystem structures.
 *
 * This function concentrates all the different computations of FAT
 * file system params.
 */
static errno_t fat_params_compute(struct fat_cfg *cfg)
{
        uint32_t fat_bytes;
        uint32_t non_data_sectors_lb_16;
        uint32_t non_data_sectors_lb;
        uint32_t rd_sectors;
        uint32_t tot_clust_16;

        /*
         * Make a conservative guess on the FAT size needed for the file
         * system. The optimum could be potentially smaller since we
         * do not subtract size of the FAT itself when computing the
         * size of the data region. Also the root dir area might not
         * need FAT entries if we decide to make a FAT32.
         */

        cfg->reserved_sectors = 1 + cfg->addt_res_sectors;

        /* Only correct for FAT12/16 (FAT32 has root dir stored in clusters) */
        rd_sectors = div_round_up(cfg->root_ent_max * DIRENT_SIZE,
            cfg->sector_size);
        non_data_sectors_lb_16 = cfg->reserved_sectors + rd_sectors;

        /* Only correct for FAT12/16 */
        tot_clust_16 = div_round_up(cfg->total_sectors - non_data_sectors_lb_16,
            cfg->sectors_per_cluster);

        /* Now detect FAT type */
        if (tot_clust_16 <= FAT12_CLST_MAX) {
                if (cfg->fat_type == FATAUTO)
                        cfg->fat_type = FAT12;
                else if (cfg->fat_type != FAT12)
                        return EINVAL;
        } else if (tot_clust_16 <= FAT16_CLST_MAX) {
                if (cfg->fat_type == FATAUTO)
                        cfg->fat_type = FAT16;
                else if (cfg->fat_type != FAT16)
                        return EINVAL;
        } else {
                if (cfg->fat_type == FATAUTO)
                        cfg->fat_type = FAT32;
                else if (cfg->fat_type != FAT32)
                        return EINVAL;
        }

        /* Actual root directory size, non-data sectors */
        if (cfg->fat_type != FAT32) {
                cfg->rootdir_sectors = div_round_up(cfg->root_ent_max * DIRENT_SIZE,
                    cfg->sector_size);
                non_data_sectors_lb = cfg->reserved_sectors + cfg->rootdir_sectors;

        } else {
                /* We create a single-cluster root dir */
                cfg->rootdir_sectors = cfg->sectors_per_cluster;
                non_data_sectors_lb = cfg->reserved_sectors;
        }

        /* Actual total number of clusters */
        cfg->total_clusters = div_round_up(cfg->total_sectors - non_data_sectors_lb,
            cfg->sectors_per_cluster);

        fat_bytes = div_round_up((cfg->total_clusters + 2) *
            FAT_CLUSTER_DOUBLE_SIZE(cfg->fat_type), 2);
        cfg->fat_sectors = div_round_up(fat_bytes, cfg->sector_size);

        if (cfg->label != NULL && fat_label_encode(NULL, cfg->label) != EOK)
                return EINVAL;

        return EOK;
}

/** Create file system with the given parameters. */
static errno_t fat_blocks_write(struct fat_cfg const *cfg, service_id_t service_id)
{
        aoff64_t addr;
        uint8_t *buffer;
        int i;
        uint32_t j;
        errno_t rc;
        struct fat_bs bs;
        fat_dentry_t *de;

        rc = fat_bootsec_create(cfg, &bs);
        if (rc != EOK)
                return rc;

        rc = block_write_direct(service_id, BS_BLOCK, 1, &bs);
        if (rc != EOK)
                return EIO;

        addr = BS_BLOCK + 1;

        buffer = calloc(cfg->sector_size, 1);
        if (buffer == NULL)
                return ENOMEM;
        memset(buffer, 0, cfg->sector_size);

        /* Reserved sectors */
        for (i = 0; i < cfg->reserved_sectors - 1; ++i) {
                rc = block_write_direct(service_id, addr, 1, buffer);
                if (rc != EOK)
                        return EIO;

                ++addr;
        }

        /* File allocation tables */
        for (i = 0; i < cfg->fat_count; ++i) {
                printf("Writing allocation table %d.\n", i + 1);

                for (j = 0; j < cfg->fat_sectors; ++j) {
                        memset(buffer, 0, cfg->sector_size);
                        if (j == 0) {
                                buffer[0] = default_media_descriptor;
                                buffer[1] = 0xFF;
                                buffer[2] = 0xFF;
                                if (cfg->fat_type == FAT16) {
                                        buffer[3] = 0xFF;
                                } else if (cfg->fat_type == FAT32) {
                                        buffer[3] = 0x0F;
                                        buffer[4] = 0xFF;
                                        buffer[5] = 0xFF;
                                        buffer[6] = 0xFF;
                                        buffer[7] = 0x0F;
                                        buffer[8] = 0xF8;
                                        buffer[9] = 0xFF;
                                        buffer[10] = 0xFF;
                                        buffer[11] = 0x0F;
                                }
                        }

                        rc = block_write_direct(service_id, addr, 1, buffer);
                        if (rc != EOK)
                                return EIO;

                        ++addr;
                }
        }

        if (cfg->fat_type == FAT32) {
                /* Root dir is stored in cluster fat32_root_cluster */
                addr += fat32_root_cluster * cfg->sectors_per_cluster;
        }

        /* Root directory */
        printf("Writing root directory.\n");
        memset(buffer, 0, cfg->sector_size);
        de = (fat_dentry_t *)buffer;
        size_t idx;
        for (idx = 0; idx < cfg->rootdir_sectors; ++idx) {

                if (idx == 0 && cfg->label != NULL) {
                        /* Set up volume label entry */
                        (void) fat_label_encode(&de->name, cfg->label);
                        de->attr = FAT_ATTR_VOLLABEL;
                        de->mtime = 0x1234; // XXX Proper time
                        de->mdate = 0x1234; // XXX Proper date
                } else if (idx == 1) {
                        /* Clear volume label entry */
                        memset(buffer, 0, cfg->sector_size);
                }

                rc = block_write_direct(service_id, addr, 1, buffer);
                if (rc != EOK)
                        return EIO;

                ++addr;
        }

        free(buffer);

        return EOK;
}

/** Construct boot sector with the given parameters. */
static errno_t fat_bootsec_create(struct fat_cfg const *cfg, struct fat_bs *bs)
{
        const char *bs_label;
        rndgen_t *rndgen;
        uint32_t vsn;
        errno_t rc;

        /* Generate a volume serial number */
        rc = rndgen_create(&rndgen);
        if (rc != EOK)
                return rc;

        rc = rndgen_uint32(rndgen, &vsn);
        if (rc != EOK) {
                rndgen_destroy(rndgen);
                return rc;
        }

        rndgen_destroy(rndgen);

        /*
         * The boot sector must always contain a valid label. If there
         * is no label, there should be 'NO NAME'
         */
        if (cfg->label != NULL)
                bs_label = cfg->label;
        else
                bs_label = LABEL_NONAME;
        memset(bs, 0, sizeof(*bs));

        bs->ji[0] = 0xEB;
        bs->ji[1] = 0x3C;
        bs->ji[2] = 0x90;

        memcpy(bs->oem_name, "HELENOS ", 8);

        /* BIOS Parameter Block */
        bs->bps = host2uint16_t_le(cfg->sector_size);
        bs->spc = cfg->sectors_per_cluster;
        bs->rscnt = host2uint16_t_le(cfg->reserved_sectors);
        bs->fatcnt = cfg->fat_count;
        bs->root_ent_max = host2uint16_t_le(cfg->root_ent_max);

        if (cfg->total_sectors < 0x10000) {
                bs->totsec16 = host2uint16_t_le(cfg->total_sectors);
                bs->totsec32 = 0;
        } else {
                bs->totsec16 = 0;
                bs->totsec32 = host2uint32_t_le(cfg->total_sectors);
        }

        bs->mdesc = default_media_descriptor;
        bs->sec_per_track = host2uint16_t_le(63);
        bs->signature = host2uint16_t_be(0x55AA);
        bs->headcnt = host2uint16_t_le(6);
        bs->hidden_sec = host2uint32_t_le(0);

        if (cfg->fat_type == FAT32) {
                bs->sec_per_fat = 0;
                bs->fat32.sectors_per_fat = host2uint32_t_le(cfg->fat_sectors);

                bs->fat32.pdn = 0x80;
                bs->fat32.ebs = 0x29;
                bs->fat32.id = host2uint32_t_be(vsn);
                bs->fat32.root_cluster = fat32_root_cluster;

                (void) fat_label_encode(&bs->fat32.label, bs_label);
                memcpy(bs->fat32.type, "FAT32   ", 8);
        } else {
                bs->sec_per_fat = host2uint16_t_le(cfg->fat_sectors);
                bs->pdn = 0x80;
                bs->ebs = 0x29;
                bs->id = host2uint32_t_be(vsn);

                (void) fat_label_encode(&bs->label, bs_label);
                if (cfg->fat_type == FAT12)
                        memcpy(bs->type, "FAT12   ", 8);
                else
                        memcpy(bs->type, "FAT16   ", 8);
        }

        return EOK;
}

/**
 * @}
 */