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daemon: Reimplement partition GPT functions using sfdisk
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sfdisk can now do everything with GPT that sgdisk was needed for
before.  In particular we are able to reimplement the following
functions using sfdisk:

- part_set_disk_guid   (replace with sfdisk --disk-id)
- part_get_disk_guid
- part_set_disk_guid_random
- part_set_gpt_attributes           (sfdisk --part-attrs)
- part_get_gpt_attributes
- part_set_gpt_guid                 (sfdisk --part-uuid)
- part_get_gpt_guid
- part_set_gpt_type                 (sfdisk --part-type)
- part_get_gpt_type

This allows us to drop the requirement for gdisk in many cases.

There is only one API remaining which requires gdisk, part_expand_gpt,
which we do not use in our tools.  In a prior commit I already moved
this solitary function to a new source file (daemon/gdisk.c).

Fixes: https://issues.redhat.com/browse/RHEL-35998
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@rwmjones
rwmjones committed May 10, 2024
1 parent a25f419 commit c6c266a
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Showing 8 changed files with 189 additions and 251 deletions.
1 change: 1 addition & 0 deletions .gitignore
View file
Expand Up @@ -108,6 +108,7 @@ Makefile.in
/daemon/parted.mli
/daemon/realpath.mli
/daemon/rpm.mli
/daemon/sfdisk.mli
/daemon/stamp-guestfsd.pod
/daemon/statvfs.mli
/daemon/structs-cleanups.c
Expand Down
3 changes: 3 additions & 0 deletions daemon/Makefile.am
View file
Expand Up @@ -59,6 +59,7 @@ generator_built = \
parted.mli \
realpath.mli \
rpm.mli \
sfdisk.mli \
statvfs.mli \
structs.ml \
structs.mli
Expand Down Expand Up @@ -306,6 +307,7 @@ SOURCES_MLI = \
parted.mli \
realpath.mli \
rpm.mli \
sfdisk.mli \
statvfs.mli \
structs.mli \
sysroot.mli \
Expand Down Expand Up @@ -337,6 +339,7 @@ SOURCES_ML = \
md.ml \
mount.ml \
mount_utils.ml \
sfdisk.ml \
parted.ml \
listfs.ml \
realpath.ml \
Expand Down
2 changes: 1 addition & 1 deletion daemon/inspect_fs_windows.ml
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Expand Up @@ -419,7 +419,7 @@ and map_registry_disk_blob_gpt partitions blob =
let typ = Parted.part_get_parttype device in
if typ <> "gpt" then false
else (
let guid = Parted.part_get_gpt_guid device partnum in
let guid = Sfdisk.part_get_gpt_guid device partnum in
String.lowercase_ascii guid = blob_guid
)
) partitions in
Expand Down
2 changes: 1 addition & 1 deletion daemon/listfs.ml
View file
Expand Up @@ -114,7 +114,7 @@ and is_partition_can_hold_filesystem partition =
else if is_mbr then
true
else (
let gpt_type = Parted.part_get_gpt_type device partnum in
let gpt_type = Sfdisk.part_get_gpt_type device partnum in
match gpt_type with
(* Windows Logical Disk Manager metadata partition. *)
| "5808C8AA-7E8F-42E0-85D2-E1E90434CFB3"
Expand Down
144 changes: 0 additions & 144 deletions daemon/parted.c
View file
Expand Up @@ -456,58 +456,6 @@ do_part_set_mbr_id (const char *device, int partnum, int idbyte)
return 0;
}

int
do_part_set_gpt_type (const char *device, int partnum, const char *guid)
{
if (partnum <= 0) {
reply_with_error ("partition number must be >= 1");
return -1;
}

CLEANUP_FREE char *typecode = NULL;
if (asprintf (&typecode, "%i:%s", partnum, guid) == -1) {
reply_with_perror ("asprintf");
return -1;
}

CLEANUP_FREE char *err = NULL;
int r = commandf (NULL, &err, COMMAND_FLAG_FOLD_STDOUT_ON_STDERR,
"sgdisk", device, "-t", typecode, NULL);

if (r == -1) {
reply_with_error ("%s %s -t %s: %s", "sgdisk", device, typecode, err);
return -1;
}

return 0;
}

int
do_part_set_gpt_guid (const char *device, int partnum, const char *guid)
{
if (partnum <= 0) {
reply_with_error ("partition number must be >= 1");
return -1;
}

CLEANUP_FREE char *typecode = NULL;
if (asprintf (&typecode, "%i:%s", partnum, guid) == -1) {
reply_with_perror ("asprintf");
return -1;
}

CLEANUP_FREE char *err = NULL;
int r = commandf (NULL, &err, COMMAND_FLAG_FOLD_STDOUT_ON_STDERR,
"sgdisk", device, "-u", typecode, NULL);

if (r == -1) {
reply_with_error ("%s %s -u %s: %s", "sgdisk", device, typecode, err);
return -1;
}

return 0;
}

char *
do_part_get_name (const char *device, int partnum)
{
Expand Down Expand Up @@ -564,95 +512,3 @@ do_part_get_name (const char *device, int partnum)
return NULL;
}
}

static char *
extract_uuid (const char *value)
{
/* The value contains only valid GUID characters */
const size_t value_len = strspn (value, "-0123456789ABCDEF");

char *ret = malloc (value_len + 1);
if (ret == NULL) {
reply_with_perror ("malloc");
return NULL;
}

memcpy (ret, value, value_len);
ret[value_len] = '\0';
return ret;
}

char *
do_part_get_disk_guid (const char *device)
{
const char *pattern = "Disk identifier (GUID):";
size_t i;

CLEANUP_FREE char *err = NULL;
int r = commandf (NULL, &err, COMMAND_FLAG_FOLD_STDOUT_ON_STDERR,
"sgdisk", device, "-p", NULL);
if (r == -1) {
reply_with_error ("%s %s -p: %s", "sgdisk", device, err);
return NULL;
}

CLEANUP_FREE_STRING_LIST char **lines = split_lines (err);
if (lines == NULL) {
reply_with_error ("'%s %s -p' returned no output",
"sgdisk", device);
return NULL;
}

for (i = 0; lines[i] != NULL; ++i) {
if (STRPREFIX (lines[i], pattern)) {
char *value = lines[i] + strlen (pattern);

/* Skip any leading whitespace */
value += strspn (value, " \t");

/* Extract the actual information from the field. */
char *ret = extract_uuid (value);
if (ret == NULL) {
/* The extraction function already sends the error. */
return NULL;
}

return ret;
}
}

/* If we got here it means we didn't find the field */
reply_with_error ("sgdisk output did not contain disk GUID. "
"See LIBGUESTFS_DEBUG output for more details");
return NULL;
}

int
do_part_set_disk_guid (const char *device, const char *guid)
{
CLEANUP_FREE char *err = NULL;
int r = commandf (NULL, &err, COMMAND_FLAG_FOLD_STDOUT_ON_STDERR,
"sgdisk", device, "-U", guid, NULL);

if (r == -1) {
reply_with_error ("%s %s -U %s: %s", "sgdisk", device, guid, err);
return -1;
}

return 0;
}

int
do_part_set_disk_guid_random (const char *device)
{
CLEANUP_FREE char *err = NULL;
int r = commandf (NULL, &err, COMMAND_FLAG_FOLD_STDOUT_ON_STDERR,
"sgdisk", device, "-U", "R", NULL);

if (r == -1) {
reply_with_error ("%s %s -U R: %s", "sgdisk", device, err);
return -1;
}

return 0;
}
92 changes: 1 addition & 91 deletions daemon/parted.ml
View file
Expand Up @@ -25,18 +25,6 @@ open Utils

include Structs

let part_get_mbr_id device partnum =
if partnum <= 0 then
failwith "partition number must be >= 1";

udev_settle ();
let out =
command "sfdisk" ["--part-type"; device; string_of_int partnum] in
udev_settle ();

(* It's printed in hex, possibly with a leading space. *)
sscanf out " %x" identity

(* This is almost equivalent to print_partition_table in the C code. The
* difference is that here we enforce the "BYT;" header internally.
*)
Expand Down Expand Up @@ -110,7 +98,7 @@ let part_get_parttype device =

let part_get_mbr_part_type device partnum =
let parttype = part_get_parttype device in
let mbr_id = part_get_mbr_id device partnum in
let mbr_id = Sfdisk.part_get_mbr_id device partnum in

(* 0x05 - extended partition.
* 0x0f - extended partition using BIOS INT 13h extensions.
Expand All @@ -120,81 +108,3 @@ let part_get_mbr_part_type device partnum =
| "msdos", (1|2|3|4), _ -> "primary"
| "msdos", _, _ -> "logical"
| _, _, _ -> "primary"

let part_set_gpt_attributes device partnum attributes =
if partnum <= 0 then failwith "partition number must be >= 1";

udev_settle ();

let arg = sprintf "%d:=:%LX" partnum attributes in
let r, _, err =
commandr ~fold_stdout_on_stderr:true
"sgdisk" [ device; "-A"; arg ] in
if r <> 0 then
failwithf "sgdisk: %s" err;

udev_settle ()

let extract_guid value =
(* The value contains only valid GUID characters. *)
String.sub value 0 (String.span value "-0123456789ABCDEF")

let extract_hex value =
(* The value contains only valid numeric characters. *)
let str = String.sub value 0 (String.span value "0123456789ABCDEF") in
Int64.of_string ("0x" ^ str)

let sgdisk_info_extract_field device partnum field extractor =
if partnum <= 0 then failwith "partition number must be >= 1";

udev_settle ();

let r, _, err =
commandr ~fold_stdout_on_stderr:true
"sgdisk" [ device; "-i"; string_of_int partnum ] in
if r <> 0 then
failwithf "getting %S: sgdisk: %s" field err;

udev_settle ();

let err = String.trim err in
let lines = String.nsplit "\n" err in

(* Parse the output of sgdisk -i:
* Partition GUID code: 21686148-6449-6E6F-744E-656564454649 (BIOS boot partition)
* Partition unique GUID: 19AEC5FE-D63A-4A15-9D37-6FCBFB873DC0
* First sector: 2048 (at 1024.0 KiB)
* Last sector: 411647 (at 201.0 MiB)
* Partition size: 409600 sectors (200.0 MiB)
* Attribute flags: 0000000000000000
* Partition name: 'EFI System Partition'
*)
let field_len = String.length field in
let rec loop = function
| [] ->
failwithf "%s: sgdisk output did not contain '%s'" device field
| line :: _ when String.is_prefix line field &&
String.length line >= field_len + 2 &&
line.[field_len] = ':' ->
let value =
String.sub line (field_len+1) (String.length line - field_len - 1) in

(* Skip any whitespace after the colon. *)
let value = String.triml value in

(* Extract the value. *)
extractor value

| _ :: lines -> loop lines
in
loop lines

let rec part_get_gpt_type device partnum =
sgdisk_info_extract_field device partnum "Partition GUID code"
extract_guid
and part_get_gpt_guid device partnum =
sgdisk_info_extract_field device partnum "Partition unique GUID"
extract_guid
and part_get_gpt_attributes device partnum =
sgdisk_info_extract_field device partnum "Attribute flags"
extract_hex

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