[syslinux:master] chain: Support booting GPT disk/partition by GUID
syslinux-bot for Shao Miller
shao.miller at yrdsb.edu.on.ca
Sat Jun 26 12:36:22 PDT 2010
Commit-ID: c6cc03c72e90e673f5b07e9bbc226b18b0e86f8f
Gitweb: http://syslinux.zytor.com/commit/c6cc03c72e90e673f5b07e9bbc226b18b0e86f8f
Author: Shao Miller <shao.miller at yrdsb.edu.on.ca>
AuthorDate: Sat, 26 Jun 2010 00:29:39 -0400
Committer: Shao Miller <shao.miller at yrdsb.edu.on.ca>
CommitDate: Sat, 26 Jun 2010 00:45:14 -0400
chain: Support booting GPT disk/partition by GUID
Use the "guid:" specifier followed by the GUID for
a GPT disk or one of its partitions.
Signed-off-by: Shao Miller <shao.miller at yrdsb.edu.on.ca>
---
NEWS | 2 +-
com32/modules/chain.c | 170 ++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 149 insertions(+), 23 deletions(-)
diff --git a/NEWS b/NEWS
index 93b64a6..3066892 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
+ * chain.c32: support booting GPT partitions by index and GUID
* 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 b4fe3ef..8f8768c 100644
--- a/com32/modules/chain.c
+++ b/com32/modules/chain.c
@@ -22,15 +22,16 @@
* chain hd<disk#> [<partition>] [options]
* chain fd<disk#> [options]
* chain mbr:<id> [<partition>] [options]
+ * chain guid:<guid> [<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:", "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:", "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.
@@ -413,8 +414,7 @@ struct mbr {
} __attribute__ ((packed));
static const uint16_t mbr_sig_magic = 0xAA55;
-/* Search for a specific drive, based on the MBR signature; bytes
- 440-443. */
+/* Search for a specific drive, based on the MBR signature; bytes 440-443 */
static int find_disk(uint32_t mbr_sig)
{
int drive;
@@ -470,6 +470,8 @@ struct disk_part_iter {
struct {
/* Real (not effective) index in the partition table */
int index;
+ /* Current partition GUID */
+ const struct guid *part_guid;
/* Count of entries in GPT */
int parts;
/* Partition record size */
@@ -620,6 +622,18 @@ struct guid {
uint64_t data4;
} __attribute__ ((packed));
+ /*
+ * This walk-map effectively reverses the little-endian
+ * portions of the GUID in the output text
+ */
+static const char guid_le_walk_map[] = {
+ 3, -1, -1, -1, 0,
+ 5, -1, 0,
+ 3, -1, 0,
+ 2, 1, 0,
+ 1, 1, 1, 1, 1, 1
+};
+
#if DEBUG
/*
* Fill a buffer with a textual GUID representation.
@@ -630,23 +644,12 @@ struct guid {
*/
static void guid_to_str(char *buf, const struct guid *id)
{
- /*
- * This walk-map effectively reverses the little-endian
- * portions of the GUID in the output text
- */
- static const char le_walk_map[] = {
- 3, -1, -1, -1, 0,
- 5, -1, 0,
- 3, -1, 0,
- 2, 1, 0,
- 1, 1, 1, 1, 1, 1
- };
unsigned int i = 0;
const char *walker = (const char *)id;
- while (i < sizeof(le_walk_map)) {
- walker += le_walk_map[i];
- if (!le_walk_map[i])
+ while (i < sizeof(guid_le_walk_map)) {
+ walker += guid_le_walk_map[i];
+ if (!guid_le_walk_map[i])
*buf = '-';
else {
*buf = ((*walker & 0xF0) >> 4) + '0';
@@ -664,6 +667,63 @@ static void guid_to_str(char *buf, const struct guid *id)
}
#endif
+/*
+ * Create a GUID structure from a textual GUID representation.
+ * The input buffer must be >= 32 hexadecimal chars and be
+ * terminated with an ASCII NUL. Returns non-zero on failure.
+ * Example: 11111111-2222-3333-4444-444444444444
+ * Endian: LLLLLLLL-LLLL-LLLL-BBBB-BBBBBBBBBBBB
+ */
+static int str_to_guid(const char *buf, struct guid *id)
+{
+ char guid_seq[sizeof(struct guid) * 2];
+ unsigned int i = 0;
+ char *walker = (char *)id;
+
+ while (*buf && i < sizeof(guid_seq)) {
+ switch (*buf) {
+ /* Skip these three characters */
+ case '{':
+ case '}':
+ case '-':
+ break;
+ default:
+ /* Copy something useful to the temp. sequence */
+ if ((*buf >= '0') && (*buf <= '9'))
+ guid_seq[i] = *buf - '0';
+ else if ((*buf >= 'A') && (*buf <= 'F'))
+ guid_seq[i] = *buf - 'A' + 10;
+ else if ((*buf >= 'a') && (*buf <= 'f'))
+ guid_seq[i] = *buf - 'a' + 10;
+ else {
+ /* Or not */
+ error("Illegal character in GUID!\n");
+ return -1;
+ }
+ i++;
+ }
+ buf++;
+ }
+ /* Check for insufficient valid characters */
+ if (i < sizeof(guid_seq)) {
+ error("Too few GUID characters!\n");
+ return -1;
+ }
+ buf = guid_seq;
+ i = 0;
+ while (i < sizeof(guid_le_walk_map)) {
+ if (!guid_le_walk_map[i])
+ i++;
+ walker += guid_le_walk_map[i];
+ *walker = *buf << 4;
+ buf++;
+ *walker |= *buf;
+ buf++;
+ i++;
+ }
+ return 0;
+}
+
/* A GPT partition */
struct gpt_part {
struct guid type;
@@ -778,6 +838,7 @@ static struct disk_part_iter *next_gpt_part(struct disk_part_iter *part)
goto err_last;
}
part->lba_data = gpt_part->lba_first;
+ part->private.gpt.part_guid = &gpt_part->uid;
/* Update our index */
part->index++;
#if DEBUG
@@ -870,6 +931,55 @@ err_alloc_iter:
return NULL;
}
+/*
+ * Search for a specific drive/partition, based on the GPT GUID.
+ * 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 or the GUID is a disk GUID,
+ * boot_part will be populated with NULL. If not matching disk is
+ * found, we return -1.
+ */
+static int find_by_guid(const struct guid *gpt_guid,
+ struct disk_part_iter **boot_part)
+{
+ int drive;
+ bool is_me;
+ struct gpt *header;
+
+ for (drive = 0x80; drive <= 0xff; drive++) {
+ if (get_disk_params(drive))
+ continue; /* Drive doesn't exist */
+ if (!(header = read_sectors(1, 1)))
+ continue; /* Cannot read sector */
+ if (memcmp(&header->sig, gpt_sig_magic, sizeof(gpt_sig_magic))) {
+ /* Not a GPT disk */
+ free(header);
+ continue;
+ }
+#if DEBUG
+ gpt_dump(header);
+#endif
+ is_me = !memcmp(&header->disk_guid, &gpt_guid, sizeof(*gpt_guid));
+ free(header);
+ if (!is_me) {
+ /* Check for a matching partition */
+ boot_part[0] = get_first_partition(NULL);
+ while (boot_part[0]) {
+ is_me =
+ !memcmp(boot_part[0]->private.gpt.part_guid, gpt_guid,
+ sizeof(*gpt_guid));
+ if (is_me)
+ break;
+ boot_part[0] = boot_part[0]->next(boot_part[0]);
+ }
+ } else
+ boot_part[0] = NULL;
+ if (is_me)
+ return drive;
+ }
+ return -1;
+}
+
static void do_boot(struct data_area *data, int ndata,
struct syslinux_rm_regs *regs)
{
@@ -1082,6 +1192,7 @@ Usage: chain.c32 [options]\n\
chain.c32 hd<disk#> [<partition>] [options]\n\
chain.c32 fd<disk#> [options]\n\
chain.c32 mbr:<id> [<partition>] [options]\n\
+ chain.c32 guid:<guid> [<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\
@@ -1111,6 +1222,7 @@ int main(int argc, char *argv[])
int i;
uint64_t fs_lba = 0; /* Syslinux partition */
uint32_t file_lba = 0;
+ struct guid gpt_guid;
unsigned char *isolinux_bin;
uint32_t *checksum, *chkhead, *chktail;
struct data_area data[3];
@@ -1179,6 +1291,8 @@ int main(int argc, char *argv[])
&& argv[i][1] == 'd')
|| !strncmp(argv[i], "mbr:", 4)
|| !strncmp(argv[i], "mbr=", 4)
+ || !strncmp(argv[i], "guid:", 5)
+ || !strncmp(argv[i], "guid=", 5)
|| !strcmp(argv[i], "boot")
|| !strncmp(argv[i], "boot,", 5)
|| !strncmp(argv[i], "fs", 2)) {
@@ -1210,6 +1324,14 @@ int main(int argc, char *argv[])
error("Unable to find requested MBR signature\n");
goto bail;
}
+ } else if (!strncmp(drivename, "guid", 4)) {
+ if (str_to_guid(drivename + 5, &gpt_guid))
+ goto bail;
+ drive = find_by_guid(&gpt_guid, &cur_part);
+ if (drive == -1) {
+ error("Unable to find requested GPT disk/partition\n");
+ goto bail;
+ }
} else if ((drivename[0] == 'h' || drivename[0] == 'f') &&
drivename[1] == 'd') {
hd = drivename[0] == 'h';
@@ -1251,8 +1373,12 @@ int main(int argc, char *argv[])
if (partition)
whichpart = strtoul(partition, NULL, 0);
+ /* "guid:" might have specified a partition */
+ if (cur_part)
+ whichpart = cur_part->index;
+
/* Boot the MBR by default */
- if (whichpart || fs_lba) {
+ if (!cur_part && (whichpart || fs_lba)) {
/* Boot a partition, possibly the Syslinux partition itself */
cur_part = get_first_partition(NULL);
while (cur_part) {
@@ -1425,8 +1551,8 @@ int main(int argc, char *argv[])
struct part_entry *record;
/* Look at the GPT partition */
const struct gpt_part *gp = (const struct gpt_part *)
- (cur_part->block +
- (cur_part->private.gpt.size * cur_part->private.gpt.index));
+ (cur_part->block +
+ (cur_part->private.gpt.size * cur_part->private.gpt.index));
/* Note the partition length */
uint64_t lba_count = gp->lba_last - gp->lba_first + 1;
/* The length of the hand-over */
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