[PATCH 10/12] partitions: dos: implement partition manipulation support
Ahmad Fatoum
a.fatoum at pengutronix.de
Wed Feb 28 09:37:45 PST 2024
Hello Sascha,
On 19.02.24 09:31, Sascha Hauer wrote:
> - pentry = xzalloc(sizeof(*pentry));
> + dpart = xzalloc(sizeof(*dpart));
> + dpart->boot_indicator = table[i].boot_indicator;
> + memcpy(dpart->chs_begin, table[i].chs_begin, sizeof(table[i].chs_begin));
> + dpart->type = table[i].type;
> + memcpy(dpart->chs_end, table[i].chs_end, sizeof(table[i].chs_end));
> +
> + pentry = &dpart->part;
>
> pentry->first_sec = first_sec;
> pentry->size = get_unaligned_le32(&table[i].partition_size);
> pentry->dos_partition_type = table[i].type;
> + pentry->num = i + 1;
I suspect this breaks my boot script for MBR systems.
Please revert to zero-based numbering.
Thanks,
Ahmad
>
> - if (signature)
> + if (signature) {
> sprintf(pentry->partuuid, "%08x-%02d", signature, i + 1);
> + dpd->signature = signature;
> + }
>
> if (is_extended_partition(pentry)) {
> + dpart->extended = true;
> pentry->size = 2;
>
> if (!extended_partition)
> @@ -226,11 +261,11 @@ static struct partition_desc *dos_partition(void *buf, struct block_device *blk)
> dev_warn(blk->dev, "Skipping additional extended partition\n");
> }
>
> - list_add_tail(&pentry->list, &pd->partitions);
> + list_add_tail(&pentry->list, &dpd->pd.partitions);
> }
>
> if (extended_partition)
> - dos_extended_partition(blk, pd, extended_partition, signature);
> + dos_extended_partition(blk, dpd, extended_partition, signature);
>
> dsp = xzalloc(sizeof(*dsp));
> dsp->blk = blk;
> @@ -249,23 +284,218 @@ static struct partition_desc *dos_partition(void *buf, struct block_device *blk)
> dos_set_disk_signature, dos_get_disk_signature,
> &dsp->signature, "%08x", dsp);
>
> - return pd;
> + return &dpd->pd;
> }
>
> static void dos_partition_free(struct partition_desc *pd)
> {
> struct partition *part, *tmp;
>
> - list_for_each_entry_safe(part, tmp, &pd->partitions, list)
> - free(part);
> + list_for_each_entry_safe(part, tmp, &pd->partitions, list) {
> + struct dos_partition *dpart = container_of(part, struct dos_partition, part);
> +
> + free(dpart);
> + }
>
> free(pd);
> }
>
> +static __maybe_unused struct partition_desc *dos_partition_create_table(struct block_device *blk)
> +{
> + struct dos_partition_desc *dpd = xzalloc(512);
> +
> + partition_desc_init(&dpd->pd, blk);
> +
> + dpd->signature = random32();
> +
> + return &dpd->pd;
> +}
> +
> +static int fs_type_to_type(const char *fstype)
> +{
> + unsigned long type;
> + int ret;
> +
> + if (!strcmp(fstype, "ext2"))
> + return 0x83;
> + if (!strcmp(fstype, "ext3"))
> + return 0x83;
> + if (!strcmp(fstype, "ext4"))
> + return 0x83;
> + if (!strcmp(fstype, "fat16"))
> + return 0xe;
> + if (!strcmp(fstype, "fat32"))
> + return 0xc;
> +
> + ret = kstrtoul(fstype, 16, &type);
> + if (ret)
> + return ret;
> +
> + if (type > 0xff)
> + return -EINVAL;
> +
> + return type;
> +}
> +
> +static __maybe_unused int dos_partition_mkpart(struct partition_desc *pd,
> + const char *name, const char *fs_type,
> + uint64_t start_lba, uint64_t end_lba)
> +{
> + struct dos_partition *dpart;
> + struct partition *part, *part_extended = NULL;
> + int npart = 0, npart_logical = 0;
> + uint64_t size;
> + int mask_free = 0xf;
> + int type = fs_type_to_type(fs_type);
> +
> + if (type < 0) {
> + pr_err("invalid fs_type \"%s\"\n", fs_type);
> + return -EINVAL;
> + }
> +
> + if (start_lba < 1) {
> + pr_err("invalid start LBA, minimum is 1\n");
> + return -EINVAL;
> + }
> +
> + list_for_each_entry(part, &pd->partitions, list) {
> + dpart = container_of(part, struct dos_partition, part);
> +
> + mask_free &= ~(1 << npart);
> +
> + if (dpart->extended)
> + part_extended = part;
> + if (dpart->logical)
> + npart_logical++;
> + else
> + npart++;
> + }
> +
> + if (!strcmp(name, "extended")) {
> + if (part_extended) {
> + pr_err("extended partition already exists\n");
> + return -ENOSPC;
> + }
> + goto create;
> + } else if (!strcmp(name, "primary")) {
> + if (npart == 4) {
> + pr_err("Can't create any more partitions\n");
> + return -ENOSPC;
> + }
> +
> + goto create;
> + } else if (!strcmp(name, "logical")) {
> + if (!part_extended) {
> + pr_err("No extended partition\n");
> + return -EINVAL;
> + }
> +
> + if (npart_logical >= 4) {
> + pr_err("Can't create any more partitions\n");
> + return -ENOSPC;
> + }
> +
> + pr_err("Can't create logical partitions yet\n");
> + return -EINVAL;
> + } else {
> + pr_err("Invalid name \"%s\"\n", name);
> + return -EINVAL;
> + }
> +
> + return 0;
> +
> +create:
> + dpart = xzalloc(sizeof(*dpart));
> + part = &dpart->part;
> +
> + if (start_lba > UINT_MAX)
> + return -ENOSPC;
> + size = end_lba - start_lba + 1;
> +
> + if (size > UINT_MAX)
> + return -ENOSPC;
> +
> + dpart->type = fs_type_to_type(fs_type);
> +
> + part->first_sec = start_lba;
> + part->size = size;
> + part->num = ffs(mask_free);
> +
> + list_add_tail(&part->list, &pd->partitions);
> +
> + return 0;
> +}
> +
> +static __maybe_unused int dos_partition_rmpart(struct partition_desc *pd, struct partition *part)
> +{
> + struct dos_partition *dpart = container_of(part, struct dos_partition, part);
> +
> + list_del(&part->list);
> + free(dpart);
> +
> + return 0;
> +}
> +
> +static __maybe_unused int dos_partition_write(struct partition_desc *pd)
> +{
> + struct dos_partition_desc *dpd = container_of(pd, struct dos_partition_desc, pd);
> + struct dos_partition *dpart;
> + struct partition *part;
> + void *buf;
> + struct partition_entry *table, *entry;
> + int ret;
> +
> + list_for_each_entry(part, &pd->partitions, list) {
> + dpart = container_of(part, struct dos_partition, part);
> + if (dpart->logical) {
> + pr_err("Cannot write tables with logical partitions yet\n");
> + return -EINVAL;
> + }
> + }
> +
> + buf = read_mbr(pd->blk);
> + if (!buf)
> + return -EIO;
> +
> + put_unaligned_le32(dpd->signature, buf + 0x1b8);
> +
> + table = buf + 0x1be;
> + memset(table, 0x0, sizeof(*table) * 4);
> +
> + *(u8 *)(buf + 0x1fe) = 0x55;
> + *(u8 *)(buf + 0x1ff) = 0xaa;
> +
> + list_for_each_entry(part, &pd->partitions, list) {
> + dpart = container_of(part, struct dos_partition, part);
> +
> + entry = &table[part->num - 1];
> +
> + entry->boot_indicator = dpart->boot_indicator;
> + memcpy(entry->chs_begin, dpart->chs_begin, sizeof(entry->chs_begin));
> + entry->type = dpart->type;
> + memcpy(entry->chs_end, dpart->chs_end, sizeof(entry->chs_end));
> + put_unaligned_le32(part->first_sec, &entry->partition_start);
> + put_unaligned_le32(part->size, &entry->partition_size);
> + }
> +
> + ret = block_write(pd->blk, buf, 0, 1);
> +
> + free(buf);
> +
> + return ret;
> +}
> +
> static struct partition_parser dos = {
> .parse = dos_partition,
> .partition_free = dos_partition_free,
> +#ifdef CONFIG_PARTITION_MANIPULATION
> + .create = dos_partition_create_table,
> + .mkpart = dos_partition_mkpart,
> + .rmpart = dos_partition_rmpart,
> + .write = dos_partition_write,
> +#endif
> .type = filetype_mbr,
> + .name = "msdos",
> };
>
> static int dos_partition_init(void)
--
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