[U-Boot] [PATCH v3 3/5] GPT: read partition table from device into a data structure

Lothar Waßmann
2017-06-06T10:43:19Z

Hi,

On Fri, 2 Jun 2017 19:22:32 -0700 alison at peloton-tech.com wrote:
> From: Alison Chaiken <alison@peloton-tech.com>
>
> Make the partition table available for modification by reading it from
> the user-specified device into a linked list. Provide an accessor
> function for command-line testing.
>
> Signed-off-by: Alison Chaiken <alison@peloton-tech.com>
> ---
> cmd/gpt.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/part.h | 7 ++++
> 2 files changed, 119 insertions(+)
>
> diff --git a/cmd/gpt.c b/cmd/gpt.c
> index 4d00a35..5c2651f 100644
> --- a/cmd/gpt.c
> +++ b/cmd/gpt.c
> @@ -19,6 +19,9 @@
> #include <linux/ctype.h>
> #include <div64.h>
> #include <memalign.h>
> +#include <linux/compat.h>
> +
> +static LIST_HEAD(disk_partitions);
>
> /**
> * extract_env(): Expand env name from string format '&{env_name}'
> @@ -151,6 +154,111 @@ static bool found_key(const char *str, const char *key)
> return result;
> }
>
> +static void del_gpt_info(void)
> +{
> + struct list_head *pos = &disk_partitions;
> + struct disk_part *curr;
> + while (!list_empty(pos)) {
> + curr = list_entry(pos->next, struct disk_part, list);
> + list_del(pos->next);
> + free(curr);
> + }
> +}
> +
> +static struct disk_part *allocate_disk_part(disk_partition_t *info, int partnum)
> +{
> + struct disk_part *newpart;
> + newpart = (struct disk_part *)malloc(sizeof(*newpart));
> + if (!newpart)
> + return ERR_PTR(-ENOMEM);
> + memset(newpart, '\0', sizeof(newpart));
> +
> + newpart->gpt_part_info.start = info->start;
> + newpart->gpt_part_info.size = info->size;
> + newpart->gpt_part_info.blksz = info->blksz;
> + strncpy((char *)newpart->gpt_part_info.name, (const char *)info->name, PART_NAME_LEN);
> + newpart->gpt_part_info.name[PART_NAME_LEN - 1] = '\0';
> + strncpy((char *)newpart->gpt_part_info.type, (const char *)info->type, PART_TYPE_LEN);
> + newpart->gpt_part_info.type[PART_TYPE_LEN - 1] = '\0';
> + newpart->gpt_part_info.bootable = info->bootable;
> +#ifdef CONFIG_PARTITION_UUIDS
> + strncpy(newpart->gpt_part_info.uuid, (const char *)info->uuid,
> + UUID_STR_LEN);
> +#endif
> + newpart->partnum = partnum;
> +
> + return newpart;
> +}
> +
> +static void print_gpt_info(void)
> +{
> + struct list_head *pos;
> + struct disk_part *curr;
> +
> + list_for_each(pos, &disk_partitions) {
> + curr = list_entry(pos, struct disk_part, list);
> + printf("Partition %d:\n", curr->partnum);
> + printf("1st block %x, size %x\n", (unsigned)curr->gpt_part_info.start,
> + (unsigned)curr->gpt_part_info.size);
> + printf("Block size %lu, name %s\n", curr->gpt_part_info.blksz,
> + curr->gpt_part_info.name);
> + printf("Type %s, bootable %d\n", curr->gpt_part_info.type,
> + curr->gpt_part_info.bootable);
> +#ifdef CONFIG_PARTITION_UUIDS
> + printf("UUID %s\n", curr->gpt_part_info.uuid);
> +#endif
> + printf("\n");
> + }
> +}
> +
> +/*
> + * read partition info into disk_partitions list where
> + * it can be printed or modified
> + */
> +static int get_gpt_info(struct blk_desc *dev_desc)
> +{
> + /* start partition numbering at 1, as U-Boot does */
> + int valid_parts = 1, p, ret;
> + disk_partition_t info;
> + struct disk_part *new_disk_part;
> +
> + if (disk_partitions.next == NULL)
> + INIT_LIST_HEAD(&disk_partitions);
> +
> + for (p = 1; p <= MAX_SEARCH_PARTITIONS; p++) {
> + ret = part_get_info(dev_desc, p, &info);
> + if (ret)
> + continue;
> +
> + new_disk_part = allocate_disk_part(&info, valid_parts);
> + if (IS_ERR(new_disk_part) && valid_parts >= 2)
> + return -ENODEV;
> +
> + list_add_tail(&new_disk_part->list, &disk_partitions);
> + valid_parts++;
> + }
> + if (!valid_parts) {
> + printf("** No valid partitions found **\n");
> + del_gpt_info();
> + return -ENODEV;
> + }
> + return --valid_parts;
> +}
> +
> +/* a wrapper to test get_gpt_info */
> +static int do_get_gpt_info(struct blk_desc *dev_desc)
> +{
> + int ret;
> +
> + ret = get_gpt_info(dev_desc);
> + if (ret > 0) {
> + print_gpt_info();
> + del_gpt_info();
> + }
> + return ret;
> +}
> +
> +
> /**
> * set_gpt_info(): Fill partition information from string
> * function allocates memory, remember to free!
> @@ -455,6 +563,8 @@ static int do_gpt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
> printf("Verify GPT: ");
> } else if (strcmp(argv[1], "guid") == 0) {
> return do_disk_guid(blk_dev_desc, argv[4]);
> + } else if (strcmp(argv[1], "read") == 0) {
> + return do_get_gpt_info(blk_dev_desc);
>
See my comment to your patch 1/5

> } else {
> return CMD_RET_USAGE;
> }

> @@ -477,6 +587,8 @@ U_BOOT_CMD(gpt, CONFIG_SYS_MAXARGS, 1, do_gpt,
> " Example usage:\n"
> " gpt write mmc 0 $partitions\n"
> " gpt verify mmc 0 $partitions\n"
> + " read <interface> <dev>\n"
> + " - read GPT into a data structure for manipulation\n"
> " guid <interface> <dev>\n"
> " - print disk GUID\n"
> " guid <interface> <dev> <varname>\n"
> diff --git a/include/part.h b/include/part.h
> index c41aa6a..0cd803a 100644
> --- a/include/part.h
> +++ b/include/part.h
> @@ -10,6 +10,7 @@
> #include <blk.h>
> #include <ide.h>
> #include <uuid.h>
> +#include <linux/list.h>
>
> struct block_drvr {
> char *name;
> @@ -69,6 +70,12 @@ typedef struct disk_partition {
> #endif
> } disk_partition_t;
>
> +struct disk_part {
> + int partnum;
> + disk_partition_t gpt_part_info;
> + struct list_head list;
> +};
> +
> /* Misc _get_dev functions */
> #ifdef CONFIG_PARTITIONS
> /**

Lothar WaÃŸmann