[U-Boot] [PATCH v5 2/3] GPT: read partition table from device into a data structure

alison at peloton-tech.com
2017-06-10T05:30:39Z

From: Alison Chaiken <alison@she-devel.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.

Changes since v4:
-- Made do_get_gpt_info() return 0 upon success so that now, in the
sandbox, u-boot prints a "success!" exit message.
-- Created a single exit point for get_gpt_info(), with the
result that after an error, del_gpt_info() always removes the
list.

Signed-off-by: Alison Chaiken <alison@peloton-tech.com>
---
cmd/gpt.c | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
include/part.h | 7 ++++
2 files changed, 127 insertions(+)

diff --git a/cmd/gpt.c b/cmd/gpt.c
index 65fb80b..669031f8 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 +154,119 @@ 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);
+ /* 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) {
+ printf("** No valid partitions found **\n");
+ goto out;
+ }
+ return --valid_parts;
+ out:
+ if (valid_parts >= 2)
+ del_gpt_info();
+ return -ENODEV;
+}
+
+/* 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 0;
+ }
+ return ret;
+}
+
+
/**
* set_gpt_info(): Fill partition information from string
* function allocates memory, remember to free!
@@ -455,6 +571,8 @@ 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) {
ret = do_disk_guid(blk_dev_desc, argv[4]);
+ } else if (strcmp(argv[1], "read") == 0) {
+ ret = do_get_gpt_info(blk_dev_desc);
} else {
return CMD_RET_USAGE;
}
@@ -477,6 +595,8 @@ 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
/**
--
2.1.4