u-boot/cmd/part_find.c

// 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"
);