[PATCH 1/2] part: Check all partitions in part_get_info_by_name()

[Heinrich Schuchardt]

On 3/28/24 23:29, Sam Protsenko wrote:
> In part_get_info_by_name() the inability to get some partition info
> shouldn't be a reason for dropping out of the loop. That might happen
> e.g. if the partition is hidden or unused. An example of such case are
> Samsung devices, where they use the "unused" GUID type
> (00000000-0000-0000-0000-000000000000) to indicate that the partition
> should be hidden from the OS. Such partitions might not be seen in
> "part list" output, which creates "gaps" in numbering in between of the
> visible partitions:
>
>      Part    Start LBA       End LBA         Name
>        1     0x00000400      0x0000a3ff      "efs"
>        5     0x00026420      0x00026c1f      "dtbo"
>       12     0x0003f390      0x0074738f      "super"
>
> In that case, the loop in part_get_info_by_name() would break after
> partition #1, so any attempt to obtain "dtbo" or "super" partition will
> fail. Fix that by continuing to iterate over the remaining partitions to
> make sure none of the visible ones is missed. That makes "part" command
> (e.g. "part start", "part size") able to work with such tables.
>
> Fixes: 87b8530fe244 ("disk: part: implement generic function part_get_info_by_name()")
> Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

> ---
>   disk/part.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/disk/part.c b/disk/part.c
> index 36b88205eca7..08c9331e059c 100644
> --- a/disk/part.c
> +++ b/disk/part.c
> @@ -717,8 +717,11 @@ int part_get_info_by_name(struct blk_desc *desc, const char *name,
>   	for (i = 1; i < part_drv->max_entries; i++) {
>   		ret = part_drv->get_info(desc, i, info);
>   		if (ret != 0) {
> -			/* no more entries in table */
> -			break;
> +			/*
> +			 * Partition with this index can't be obtained, but
> +			 * further partitions might be, so keep checking.
> +			 */
> +			continue;
>   		}
>   		if (strcmp(name, (const char *)info->name) == 0) {
>   			/* matched */