New partition APIs: part_del, part_get_bootable, part_get/set_mbr_id

These APIs flesh out further the partitioning API.

daemon/parted.c

@@ -158,6 +158,18 @@ do_part_add (const char *device, const char *prlogex,
   return 0;
 }
 
+int
+do_part_del (const char *device, int partnum)
+{
+  char partnum_str[16];
+  snprintf (partnum_str, sizeof partnum_str, "%d", partnum);
+
+  RUN_PARTED (return -1, device, "rm", partnum_str, NULL);
+
+  udev_settle ();
+  return 0;
+}
+
 int
 do_part_disk (const char *device, const char *parttype)
 {
@@ -371,3 +383,92 @@ do_part_list (const char *device)
   free_strings (lines);
   return NULL;
 }
+
+int
+do_part_get_bootable (const char *device, int partnum)
+{
+  char **lines = print_partition_table (device);
+  if (!lines)
+    return -1;
+
+  /* We want lines[1+partnum]. */
+  if (count_strings (lines) < 1+partnum) {
+    reply_with_error ("partition number out of range: %d", partnum);
+    free_strings (lines);
+    return -1;
+  }
+
+  char *boot = get_table_field (lines[1+partnum], 6);
+  if (boot == NULL) {
+    free_strings (lines);
+    return -1;
+  }
+
+  int r = STREQ (boot, "boot");
+
+  free (boot);
+  free_strings (lines);
+
+  return r;
+}
+
+/* Currently we use sfdisk for getting and setting the ID byte.  In
+ * future, extend parted to provide this functionality.  As a result
+ * of using sfdisk, this won't work for non-MBR-style partitions, but
+ * that limitation is noted in the documentation and we can extend it
+ * later without breaking the ABI.
+ */
+int
+do_part_get_mbr_id (const char *device, int partnum)
+{
+  char partnum_str[16];
+  snprintf (partnum_str, sizeof partnum_str, "%d", partnum);
+
+  char *out, *err;
+  int r;
+
+  r = command (&out, &err, "sfdisk", "--print-id", device, partnum_str, NULL);
+  if (r == -1) {
+    reply_with_error ("sfdisk --print-id: %s", err);
+    free (out);
+    free (err);
+    return -1;
+  }
+
+  free (err);
+
+  /* It's printed in hex ... */
+  int id;
+  if (sscanf (out, "%x", &id) != 1) {
+    reply_with_error ("sfdisk --print-id: cannot parse output: %s", out);
+    free (out);
+    return -1;
+  }
+
+  free (out);
+  return id;
+}
+
+int
+do_part_set_mbr_id (const char *device, int partnum, int idbyte)
+{
+  char partnum_str[16];
+  snprintf (partnum_str, sizeof partnum_str, "%d", partnum);
+
+  char idbyte_str[16];
+  snprintf (idbyte_str, sizeof partnum_str, "%x", idbyte); /* NB: hex */
+
+  char *err;
+  int r;
+
+  r = command (NULL, &err, "sfdisk",
+               "--change-id", device, partnum_str, idbyte_str, NULL);
+  if (r == -1) {
+    reply_with_error ("sfdisk --change-id: %s", err);
+    free (err);
+    return -1;
+  }
+
+  free (err);
+  return 0;
+}

src/MAX_PROC_NR

@@ -1 +1 @@
-230
+236

src/generator.ml

@@ -4388,6 +4388,61 @@ See also L<ntfsresize(8)>.");
 This rescans all block devices and rebuilds the list of LVM
 physical volumes, volume groups and logical volumes.");
 
+  ("part_del", (RErr, [Device "device"; Int "partnum"]), 233, [],
+   [InitEmpty, Always, TestRun (
+      [["part_init"; "/dev/sda"; "mbr"];
+       ["part_add"; "/dev/sda"; "primary"; "1"; "-1"];
+       ["part_del"; "/dev/sda"; "1"]])],
+   "delete a partition",
+   "\
+This command deletes the partition numbered C<partnum> on C<device>.
+
+Note that in the case of MBR partitioning, deleting an
+extended partition also deletes any logical partitions
+it contains.");
+
+  ("part_get_bootable", (RBool "bootable", [Device "device"; Int "partnum"]), 234, [],
+   [InitEmpty, Always, TestOutputTrue (
+      [["part_init"; "/dev/sda"; "mbr"];
+       ["part_add"; "/dev/sda"; "primary"; "1"; "-1"];
+       ["part_set_bootable"; "/dev/sda"; "1"; "true"];
+       ["part_get_bootable"; "/dev/sda"; "1"]])],
+   "return true if a partition is bootable",
+   "\
+This command returns true if the partition C<partnum> on
+C<device> has the bootable flag set.
+
+See also C<guestfs_part_set_bootable>.");
+
+  ("part_get_mbr_id", (RInt "idbyte", [Device "device"; Int "partnum"]), 235, [],
+   [InitEmpty, Always, TestOutputInt (
+      [["part_init"; "/dev/sda"; "mbr"];
+       ["part_add"; "/dev/sda"; "primary"; "1"; "-1"];
+       ["part_set_mbr_id"; "/dev/sda"; "1"; "0x7f"];
+       ["part_get_mbr_id"; "/dev/sda"; "1"]], 0x7f)],
+   "get the MBR type byte (ID byte) from a partition",
+   "\
+Returns the MBR type byte (also known as the ID byte) from
+the numbered partition C<partnum>.
+
+Note that only MBR (old DOS-style) partitions have type bytes.
+You will get undefined results for other partition table
+types (see C<guestfs_part_get_parttype>).");
+
+  ("part_set_mbr_id", (RErr, [Device "device"; Int "partnum"; Int "idbyte"]), 236, [],
+   [], (* tested by part_get_mbr_id *)
+   "set the MBR type byte (ID byte) of a partition",
+   "\
+Sets the MBR type byte (also known as the ID byte) of
+the numbered partition C<partnum> to C<idbyte>.  Note
+that the type bytes quoted in most documentation are
+in fact hexadecimal numbers, but usually documented
+without any leading \"0x\" which might be confusing.
+
+Note that only MBR (old DOS-style) partitions have type bytes.
+You will get undefined results for other partition table
+types (see C<guestfs_part_get_parttype>).");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions