[U-Boot] [PATCH v7 8/9] GPT: read partition table from device into a data structure

["Lothar Waßmann" <LW@KARO-electronics.de>]

Hi,

On Sun, 25 Jun 2017 16:43:24 -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.
> 
> Change since v6:
> -- Removed a cast in allocate_disk_part() as suggested by Lothar.
> 
> Signed-off-by: Alison Chaiken <alison@peloton-tech.com>
> ---
>  cmd/gpt.c      | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/part.h |   7 ++++
>  2 files changed, 126 insertions(+)
> 
> diff --git a/cmd/gpt.c b/cmd/gpt.c
> index 65fb80b..9934ef4 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 +154,118 @@ 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 = 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);
> +	/* UUID_STR_LEN is correct, as uuid[]'s length is UUID_STR_LEN+1 chars */
> +	newpart->gpt_part_info.uuid[UUID_STR_LEN] = '\0';
> +#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))
> +			goto out;
> +
> +		list_add_tail(&new_disk_part->list, &disk_partitions);
> +		valid_parts++;
> +	}
> +	if (!valid_parts) {
>
You initialize valid_parts to '1' and only ever increment it, so it can
never be '0' here.


Lothar Waßmann