[syslinux:master] chain: Support booting GPT partition by label
syslinux-bot for Shao Miller
shao.miller at yrdsb.edu.on.ca
Sat Jun 26 12:36:23 PDT 2010
Commit-ID: bf4d5601341becb4454304a6252ee1f43a713809
Gitweb: http://syslinux.zytor.com/commit/bf4d5601341becb4454304a6252ee1f43a713809
Author: Shao Miller <shao.miller at yrdsb.edu.on.ca>
AuthorDate: Sat, 26 Jun 2010 02:19:04 -0400
Committer: Shao Miller <shao.miller at yrdsb.edu.on.ca>
CommitDate: Sat, 26 Jun 2010 03:55:05 -0700
chain: Support booting GPT partition by label
Use the "label:" specifier followed by the label for
one of a GPT disk's partitions.
Signed-off-by: Shao Miller <shao.miller at yrdsb.edu.on.ca>
---
NEWS | 2 +-
com32/modules/chain.c | 77 +++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 73 insertions(+), 6 deletions(-)
diff --git a/NEWS b/NEWS
index 3066892..7fd76c3 100644
--- a/NEWS
+++ b/NEWS
@@ -3,7 +3,7 @@ or EXTLINUX apply to that specific program only; other changes apply
to all derivatives.
Changes in 4.00:
- * chain.c32: support booting GPT partitions by index and GUID
+ * chain.c32: support booting GPT partitions by index, GUID, label
* chain.c32: support booting the Syslinux partition with "fs"
* chain.c32: implement gpt.txt hand-over protocol
Changes in 3.86:
diff --git a/com32/modules/chain.c b/com32/modules/chain.c
index 8f8768c..4af7b25 100644
--- a/com32/modules/chain.c
+++ b/com32/modules/chain.c
@@ -23,15 +23,17 @@
* chain fd<disk#> [options]
* chain mbr:<id> [<partition>] [options]
* chain guid:<guid> [<partition>] [options]
+ * chain label:<label> [<partition>] [options]
* chain boot [<partition>] [options]
*
* For example, "chain msdos=io.sys" will load DOS from the current Syslinux
* filesystem. "chain hd0 1" will boot the first partition on the first hard
* disk.
*
- * When none of the "hdX", "fdX", "mbr:", "guid:", "boot" or "fs" options are
- * specified, the default behaviour is equivalent to "boot". "boot" means to
- * use the current Syslinux drive, and you can also specify a partition.
+ * When none of the "hdX", "fdX", "mbr:", "guid:", "label:", "boot" or "fs"
+ * options are specified, the default behaviour is equivalent to "boot".
+ * "boot" means to use the current Syslinux drive, and you can also specify
+ * a partition.
*
* The mbr: syntax means search all the hard disks until one with a
* specific MBR serial number (bytes 440-443) is found.
@@ -472,6 +474,8 @@ struct disk_part_iter {
int index;
/* Current partition GUID */
const struct guid *part_guid;
+ /* Current partition label */
+ const char *part_label;
/* Count of entries in GPT */
int parts;
/* Partition record size */
@@ -839,6 +843,7 @@ static struct disk_part_iter *next_gpt_part(struct disk_part_iter *part)
}
part->lba_data = gpt_part->lba_first;
part->private.gpt.part_guid = &gpt_part->uid;
+ part->private.gpt.part_label = gpt_part->name;
/* Update our index */
part->index++;
#if DEBUG
@@ -980,6 +985,56 @@ static int find_by_guid(const struct guid *gpt_guid,
return -1;
}
+/*
+ * Search for a specific partition, based on the GPT label.
+ * We return the disk drive number if found, as well as populating the
+ * boot_part pointer with the matching partition, if applicable.
+ * If no matching partition is found, boot_part will be populated with
+ * NULL and we return -1.
+ */
+static int find_by_label(const char *label, struct disk_part_iter **boot_part)
+{
+ int drive;
+ bool is_me;
+
+ for (drive = 0x80; drive <= 0xff; drive++) {
+ if (get_disk_params(drive))
+ continue; /* Drive doesn't exist */
+ /* Check for a GPT disk */
+ boot_part[0] = get_first_partition(NULL);
+ if (!(boot_part[0]->next == next_gpt_part)) {
+ /* Not a GPT disk */
+ while (boot_part[0]) {
+ /* Run through until the end */
+ boot_part[0] = boot_part[0]->next(boot_part[0]);
+ }
+ continue;
+ }
+ /* Check for a matching partition */
+ while (boot_part[0]) {
+ char gpt_label[sizeof(((struct gpt_part *) NULL)->name)];
+ const char *gpt_label_scanner =
+ boot_part[0]->private.gpt.part_label;
+ int j = 0;
+
+ /* Re-write the GPT partition label as ASCII */
+ while (gpt_label_scanner <
+ boot_part[0]->private.gpt.part_label + sizeof(gpt_label)) {
+ if ((gpt_label[j] = *gpt_label_scanner))
+ j++;
+ gpt_label_scanner++;
+ }
+ if ((is_me = !strcmp(label, gpt_label)))
+ break;
+ boot_part[0] = boot_part[0]->next(boot_part[0]);
+ }
+ if (is_me)
+ return drive;
+ }
+
+ return -1;
+}
+
static void do_boot(struct data_area *data, int ndata,
struct syslinux_rm_regs *regs)
{
@@ -1193,6 +1248,7 @@ Usage: chain.c32 [options]\n\
chain.c32 fd<disk#> [options]\n\
chain.c32 mbr:<id> [<partition>] [options]\n\
chain.c32 guid:<guid> [<partition>] [options]\n\
+ chain.c32 label:<label> [<partition>] [options]\n\
chain.c32 boot [<partition>] [options]\n\
chain.c32 fs [options]\n\
Options: file=<loader> Load and execute file, instead of boot sector\n\
@@ -1293,6 +1349,8 @@ int main(int argc, char *argv[])
|| !strncmp(argv[i], "mbr=", 4)
|| !strncmp(argv[i], "guid:", 5)
|| !strncmp(argv[i], "guid=", 5)
+ || !strncmp(argv[i], "label:", 6)
+ || !strncmp(argv[i], "label=", 6)
|| !strcmp(argv[i], "boot")
|| !strncmp(argv[i], "boot,", 5)
|| !strncmp(argv[i], "fs", 2)) {
@@ -1332,6 +1390,16 @@ int main(int argc, char *argv[])
error("Unable to find requested GPT disk/partition\n");
goto bail;
}
+ } else if (!strncmp(drivename, "label", 5)) {
+ if (!drivename[6]) {
+ error("No label specified.\n");
+ goto bail;
+ }
+ drive = find_by_label(drivename + 6, &cur_part);
+ if (drive == -1) {
+ error("Unable to find requested partition by label\n");
+ goto bail;
+ }
} else if ((drivename[0] == 'h' || drivename[0] == 'f') &&
drivename[1] == 'd') {
hd = drivename[0] == 'h';
@@ -1372,8 +1440,7 @@ int main(int argc, char *argv[])
if (partition)
whichpart = strtoul(partition, NULL, 0);
-
- /* "guid:" might have specified a partition */
+ /* "guid:" or "label:" might have specified a partition */
if (cur_part)
whichpart = cur_part->index;
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