From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Majewski Date: Wed, 31 May 2017 09:44:43 +0200 Subject: [U-Boot] [PATCH v2 3/6] GPT: add accessor function for disk GUID In-Reply-To: <1496076573-14495-4-git-send-email-alison@peloton-tech.com> References: <20170526123845.GI10782@bill-the-cat> <1496076573-14495-1-git-send-email-alison@peloton-tech.com> <1496076573-14495-4-git-send-email-alison@peloton-tech.com> Message-ID: <20170531094443.7a57e48d@jawa> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Alison, > From: Alison Chaiken > > In order to read the GPT, modify the partition name strings, and then > write out a new GPT, the disk GUID is needed. While there is an > existing accessor for the partition UUIDs, there is none yet for the > disk GUID. Acked-by: Lukasz Majewski > > Signed-off-by: Alison Chaiken > --- > cmd/gpt.c | 30 +++++++++++++++++++++++++++++- > disk/part_efi.c | 31 +++++++++++++++++++++++++++++++ > doc/README.gpt | 3 ++- > include/part.h | 15 +++++++++++++++ > 4 files changed, 77 insertions(+), 2 deletions(-) > > diff --git a/cmd/gpt.c b/cmd/gpt.c > index 3e98821..3b7d929 100644 > --- a/cmd/gpt.c > +++ b/cmd/gpt.c > @@ -398,6 +398,23 @@ static int gpt_verify(struct blk_desc > *blk_dev_desc, const char *str_part) return ret; > } > > +static int do_disk_guid(struct blk_desc *dev_desc, char * const > namestr) +{ > + int ret; > + char disk_guid[UUID_STR_LEN + 1]; > + > + ret = get_disk_guid(dev_desc, disk_guid); > + if (ret < 0) > + return 1; > + > + if (namestr) > + setenv(namestr, disk_guid); > + else > + printf("%s\n", disk_guid); > + > + return 0; > +} > + > /** > * do_gpt(): Perform GPT operations > * > @@ -412,7 +429,7 @@ static int do_gpt(cmd_tbl_t *cmdtp, int flag, int > argc, char * const argv[]) { > int ret = CMD_RET_SUCCESS; > int dev = 0; > - char *ep; > + char *ep, *varname = NULL; > struct blk_desc *blk_dev_desc = NULL; > > if (argc < 4 || argc > 5) > @@ -436,6 +453,10 @@ static int do_gpt(cmd_tbl_t *cmdtp, int flag, > int argc, char * const argv[]) } else if ((strcmp(argv[1], "verify") > == 0)) { ret = gpt_verify(blk_dev_desc, argv[4]); > printf("Verify GPT: "); > + } else if (strcmp(argv[1], "guid") == 0) { > + if (argc == 5) > + strcpy(varname, argv[4]); > + return do_disk_guid(blk_dev_desc, varname); > } else { > return CMD_RET_USAGE; > } > @@ -458,4 +479,11 @@ 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" > + " guid \n" > + " - print disk GUID\n" > + " guid \n" > + " - set environment variable to disk GUID\n" > + " Example usage:\n" > + " gpt guid mmc 0\n" > + " gpt guid mmc 0 varname\n" > ); > diff --git a/disk/part_efi.c b/disk/part_efi.c > index 20d33ef..ff9f408 100644 > --- a/disk/part_efi.c > +++ b/disk/part_efi.c > @@ -178,6 +178,37 @@ static void prepare_backup_gpt_header(gpt_header > *gpt_h) > * Public Functions (include/part.h) > */ > > +/* > + * UUID is displayed as 32 hexadecimal digits, in 5 groups, > + * separated by hyphens, in the form 8-4-4-4-12 for a total of 36 > characters > + */ > +int get_disk_guid(struct blk_desc * dev_desc, char *guid) > +{ > + ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, > dev_desc->blksz); > + gpt_entry *gpt_pte = NULL; > + unsigned char *guid_bin; > + > + /* This function validates AND fills in the GPT header and > PTE */ > + if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA, > + gpt_head, &gpt_pte) != 1) { > + printf("%s: *** ERROR: Invalid GPT ***\n", __func__); > + if (is_gpt_valid(dev_desc, (dev_desc->lba - 1), > + gpt_head, &gpt_pte) != 1) { > + printf("%s: *** ERROR: Invalid Backup GPT > ***\n", > + __func__); > + return -1; > + } else { > + printf("%s: *** Using Backup GPT > ***\n", > + __func__); > + } > + } > + > + guid_bin = (unsigned char *)(gpt_head->disk_guid.b); > + uuid_bin_to_str(guid_bin, guid, UUID_STR_FORMAT_GUID); > + > + return 0; > +} > + > void part_print_efi(struct blk_desc *dev_desc) > { > ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, > dev_desc->blksz); diff --git a/doc/README.gpt b/doc/README.gpt > index 3fcd835..c0779a4 100644 > --- a/doc/README.gpt > +++ b/doc/README.gpt > @@ -171,7 +171,8 @@ To restore GUID partition table one needs to: > The fields 'uuid' and 'uuid_disk' are optional if > CONFIG_RANDOM_UUID is enabled. A random uuid will be used if omitted > or they point to an empty/ non-existent environment variable. The > environment variable will be set to > - the generated UUID. > + the generated UUID. The 'gpt guid' command reads the current > value of the > + uuid_disk from the GPT. > > The field 'bootable' is optional, it is used to mark the GPT > partition bootable (set attribute flags "Legacy BIOS bootable"). > diff --git a/include/part.h b/include/part.h > index 87b1111..16c4a46 100644 > --- a/include/part.h > +++ b/include/part.h > @@ -371,6 +371,21 @@ int gpt_verify_headers(struct blk_desc > *dev_desc, gpt_header *gpt_head, int gpt_verify_partitions(struct > blk_desc *dev_desc, disk_partition_t *partitions, int parts, > gpt_header *gpt_head, gpt_entry **gpt_pte); > + > + > +/** > + * get_disk_guid() - Function to read the GUID string from a > device's GPT > + * > + * This function reads the GUID string from a block device whose > descriptor > + * is provided. > + * > + * @param dev_desc - block device descriptor > + * @param guid - pre-allocated string in which to return the GUID > + * > + * @return - '0' on success, otherwise error > + */ > +int get_disk_guid(struct blk_desc *dev_desc, char *guid); > + > #endif > > #if CONFIG_IS_ENABLED(DOS_PARTITION) Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de