Re: [PATCH 02/10] Add part_find command

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 23.11.24 20:55, Matthew Garrett wrote:
> From: Matthew Garrett <mgarrett@aurora.tech>
>
> part_find takes a GPT GUID and searches for a partition that matches
> that. It then sets the target_part environment variable to the media
> type, device number and partition number that matched, allowing
> $target_part to be passed directly to bootm and similar commands.
>
> Signed-off-by: Matthew Garrett <mgarrett@aurora.tech>

For user to memorize the command it would be preferable to add the
functionality as sub-command to the existing part command.

Best regards

Heinrich

> ---
>
>   cmd/Kconfig     |  10 ++++
>   cmd/Makefile    |   1 +
>   cmd/part_find.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 167 insertions(+)
>   create mode 100644 cmd/part_find.c
>
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index 1d7ddb4ed36..ee85928ca21 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -1529,6 +1529,16 @@ config CMD_PART
>   	  Read and display information about the partition table on
>   	  various media.
>
> +config CMD_PART_FIND
> +	bool "part_find"
> +	depends on PARTITIONS
> +	select HAVE_BLOCK_DEVICE
> +	select PARTITION_UUIDS
> +	select PARTITION_TYPE_GUID
> +	help
> +	  Find a partition with a given type GUID and set the target_part
> +	  environment variable if located.
> +
>   config CMD_PCI
>   	bool "pci - Access PCI devices"
>   	help
> diff --git a/cmd/Makefile b/cmd/Makefile
> index d1f369deec0..16fd8dcd723 100644
> --- a/cmd/Makefile
> +++ b/cmd/Makefile
> @@ -137,6 +137,7 @@ obj-$(CONFIG_CMD_NVEDIT_EFI) += nvedit_efi.o
>   obj-$(CONFIG_CMD_ONENAND) += onenand.o
>   obj-$(CONFIG_CMD_OSD) += osd.o
>   obj-$(CONFIG_CMD_PART) += part.o
> +obj-$(CONFIG_CMD_PART_FIND) += part_find.o
>   obj-$(CONFIG_CMD_PCAP) += pcap.o
>   ifdef CONFIG_PCI
>   obj-$(CONFIG_CMD_PCI) += pci.o
> diff --git a/cmd/part_find.c b/cmd/part_find.c
> new file mode 100644
> index 00000000000..8c071d3c374
> --- /dev/null
> +++ b/cmd/part_find.c
> @@ -0,0 +1,156 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Aurora Innovation, Inc. Copyright 2022.
> + *
> + */
> +
> +#include <blk.h>
> +#include <config.h>
> +#include <command.h>
> +#include <dm.h>
> +#include <env.h>
> +#include <part.h>
> +#if defined(CONFIG_EFI) || defined(CONFIG_EFI_APP)
> +#include <efi.h>
> +#include <efi_api.h>
> +
> +static bool partition_is_on_device(const struct efi_device_path *device,
> +				   const struct efi_device_path *part,
> +				   __u32 *part_no)
> +{
> +	size_t d_len, p_len;
> +	const struct efi_device_path *p, *d;
> +
> +	for (d = device; d->type != DEVICE_PATH_TYPE_END; d = (void *)d + d->length) {
> +	}
> +
> +	d_len = (void *)d - (void *)device;
> +
> +	for (p = part; p->type != DEVICE_PATH_TYPE_END &&
> +		     !(p->type == DEVICE_PATH_TYPE_MEDIA_DEVICE &&
> +		       p->sub_type == DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH);
> +	     p = (void *)p + p->length) {
> +	}
> +
> +	if (p->type != DEVICE_PATH_TYPE_MEDIA_DEVICE ||
> +	    p->sub_type != DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH) {
> +		// Not a partition.
> +		return false;
> +	}
> +
> +	p_len = (void *)p - (void *)part;
> +
> +	if (p_len == d_len && !memcmp(device, part, p_len)) {
> +		if (part_no)
> +			*part_no = ((__u32 *)p)[1];
> +		return true;
> +	}
> +	return false;
> +}
> +#endif
> +
> +static int part_find(int argc, char *const argv[])
> +{
> +#if defined(CONFIG_EFI) || defined(CONFIG_EFI_APP)
> +	efi_guid_t efi_devpath_guid = EFI_DEVICE_PATH_PROTOCOL_GUID;
> +	struct efi_device_path *loaded_image_path = NULL;
> +	struct efi_boot_services *boot = efi_get_boot();
> +	struct efi_priv *priv = efi_get_priv();
> +	bool part_self = false;
> +#endif
> +	struct driver *d = ll_entry_start(struct driver, driver);
> +	const int n_ents = ll_entry_count(struct driver, driver);
> +	struct disk_partition info;
> +	struct blk_desc *desc;
> +	struct driver *entry;
> +	struct udevice *udev;
> +	struct uclass *uc;
> +	int ret;
> +
> +	if (argc != 2)
> +		return CMD_RET_USAGE;
> +
> +#if defined(CONFIG_EFI) || defined (CONFIG_EFI_APP)
> +	part_self = !strncmp(argv[1], "self", 6);
> +	if (part_self) {
> +		ret = boot->handle_protocol(priv->loaded_image->device_handle,
> +					&efi_devpath_guid,
> +					(void **)&loaded_image_path);
> +		if (ret)
> +			log_warning("failed to get device path for loaded image (ret=%d)", ret);
> +	}
> +#endif
> +
> +	ret = uclass_get(UCLASS_BLK, &uc);
> +	if (ret) {
> +		puts("Could not get BLK uclass.\n");
> +		return CMD_RET_FAILURE;
> +	}
> +	for (entry = d; entry < d + n_ents; entry++) {
> +		if (entry->id != UCLASS_BLK)
> +			continue;
> +		uclass_foreach_dev(udev, uc) {
> +			int i;
> +
> +			if (udev->driver != entry)
> +				continue;
> +			desc = dev_get_uclass_plat(udev);
> +#if defined(CONFIG_EFI) || defined(CONFIG_EFI_APP)
> +			if (part_self) {
> +				if (desc->if_type == IF_TYPE_EFI_MEDIA) {
> +					struct efi_media_plat *plat =
> +						dev_get_plat(udev->parent);
> +					__u32 loader_part_no;
> +
> +					if (partition_is_on_device(plat->device_path,
> +								   loaded_image_path,
> +								   &loader_part_no)) {
> +						char env[256];
> +
> +						ret = snprintf(env, sizeof(env), "%s %d:%d", blk_get_if_type_name(desc->if_type), desc->devnum, loader_part_no);
> +						if (ret < 0 || ret == sizeof(env))
> +							return CMD_RET_FAILURE;
> +						if (env_set("target_part", env))
> +							return CMD_RET_FAILURE;
> +						return CMD_RET_SUCCESS;
> +					}
> +				}
> +			} else {
> +#endif
> +				for (i = 1; i <= MAX_SEARCH_PARTITIONS; i++) {
> +					ret = part_get_info(desc, i, &info);
> +					if (ret)
> +						break;
> +					if (strcasecmp(argv[1], info.type_guid) == 0) {
> +						char env[256];
> +						ret = snprintf(env, sizeof(env), "%s %d:%d", blk_get_if_type_name(desc->if_type), desc->devnum, i);
> +						if (ret < 0 || ret == sizeof(env))
> +							return CMD_RET_FAILURE;
> +						env_set("target_part", env);
> +						debug("Setting target_part to %s\n", env);
> +						return CMD_RET_SUCCESS;
> +					}
> +				}
> +#if defined(CONFIG_EFI) || defined(CONFIG_EFI_APP)
> +			}
> +#endif
> +		}
> +	}
> +
> +	return CMD_RET_FAILURE;
> +}
> +
> +static int do_part_find(struct cmd_tbl *cmdtp, int flag, int argc,
> +			char *const argv[])
> +{
> +	return part_find(argc, argv);
> +}
> +
> +U_BOOT_CMD(
> +	part_find, 2, 0, do_part_find, "Find a partition",
> +	"<guid>\n"
> +	"- Examine the list of known partitions for one that has a type\n"
> +	"  GUID that matches 'guid', expressed in the standard text format.\n"
> +	"  If successful, the target_part environment variable will be set\n"
> +	"  to the corresponding 'interface dev:part'.\n"
> +);