4 files changed, 127 insertions, 0 deletions

diff --git a/cgpt/cgpt.c b/cgpt/cgpt.c
index 38092006..0977b654 100644
--- a/cgpt/cgpt.c
+++ b/cgpt/cgpt.c
@@ -34,6 +34,7 @@ struct {
   {"repair", cmd_repair, "Repair damaged GPT headers and tables"},
   {"boot", cmd_boot, "Edit the PMBR sector for legacy BIOSes"},
   {"find", cmd_find, "Locate a partition by its GUID"},
+  {"edit", cmd_edit, "Edit a drive entry"},
   {"prioritize", cmd_prioritize,
    "Reorder the priority of all kernel partitions"},
   {"legacy", cmd_legacy, "Switch between GPT and Legacy GPT"},
diff --git a/cgpt/cgpt.h b/cgpt/cgpt.h
index 86f4b851..c53f0f32 100644
--- a/cgpt/cgpt.h
+++ b/cgpt/cgpt.h
@@ -201,6 +201,7 @@ int cmd_create(int argc, char *argv[]);
 int cmd_add(int argc, char *argv[]);
 int cmd_boot(int argc, char *argv[]);
 int cmd_find(int argc, char *argv[]);
+int cmd_edit(int argc, char *argv[]);
 int cmd_prioritize(int argc, char *argv[]);
 int cmd_legacy(int argc, char *argv[]);
 
diff --git a/cgpt/cgpt_edit.c b/cgpt/cgpt_edit.c
new file mode 100644
index 00000000..098187f6
--- /dev/null
+++ b/cgpt/cgpt_edit.c
@@ -0,0 +1,47 @@
+// Copyright 2018 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cgpt.h"
+#include "cgpt_params.h"
+#include "cgptlib_internal.h"
+#include "vboot_host.h"
+
+int CgptEdit(CgptEditParams *params) {
+  struct drive drive;
+  GptHeader *h;
+  int gpt_retval;
+
+  if (params == NULL)
+    return CGPT_FAILED;
+
+  if (CGPT_OK != DriveOpen(params->drive_name, &drive, O_RDWR, 0))
+    return CGPT_FAILED;
+
+  if (GPT_SUCCESS != (gpt_retval = GptSanityCheck(&drive.gpt))) {
+    Error("GptSanityCheck() returned %d: %s\n",
+          gpt_retval, GptError(gpt_retval));
+    goto bad;
+  }
+
+  if (CGPT_OK != CheckValid(&drive)) {
+    Error("Please run 'cgpt repair' before changing settings.\n");
+    goto bad;
+  }
+
+  h = (GptHeader *)drive.gpt.primary_header;
+  memcpy(&h->disk_uuid, &params->unique_guid, sizeof(h->disk_uuid));
+  // Copy to secondary
+  RepairHeader(&drive.gpt, MASK_PRIMARY);
+  drive.gpt.modified |= (GPT_MODIFIED_HEADER1 | GPT_MODIFIED_HEADER2);
+
+  UpdateCrc(&drive.gpt);
+
+  // Write it all out.
+  return DriveClose(&drive, 1);
+
+bad:
+
+  DriveClose(&drive, 0);
+  return CGPT_FAILED;
+}
diff --git a/cgpt/cmd_edit.c b/cgpt/cmd_edit.c
new file mode 100644
index 00000000..4f4290b9
--- /dev/null
+++ b/cgpt/cmd_edit.c
@@ -0,0 +1,78 @@
+// Copyright 2018 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <getopt.h>
+
+#include "cgpt.h"
+#include "vboot_host.h"
+
+extern const char* progname;
+
+static void Usage(void)
+{
+  printf("\nUsage: %s edit [OPTIONS] DRIVE\n\n"
+         "Edit a drive's parameters.\n\n"
+         "Options:\n"
+         "  -u GUID      Drive Unique ID\n"
+         "\n", progname);
+}
+
+int cmd_edit(int argc, char *argv[]) {
+
+  CgptEditParams params;
+  memset(&params, 0, sizeof(params));
+
+  int c;
+  int errorcnt = 0;
+
+  opterr = 0;                     // quiet, you
+  while ((c=getopt(argc, argv, ":hu:")) != -1)
+  {
+    switch (c)
+    {
+    case 'u':
+      params.set_unique = 1;
+      if (CGPT_OK != StrToGuid(optarg, &params.unique_guid)) {
+        Error("invalid argument to -%c: %s\n", c, optarg);
+        errorcnt++;
+      }
+      break;
+    case 'h':
+      Usage();
+      return CGPT_OK;
+    case '?':
+      Error("unrecognized option: -%c\n", optopt);
+      errorcnt++;
+      break;
+    case ':':
+      Error("missing argument to -%c\n", optopt);
+      errorcnt++;
+      break;
+    default:
+      errorcnt++;
+      break;
+    }
+  }
+  if (errorcnt)
+  {
+    Usage();
+    return CGPT_FAILED;
+  }
+
+  if (optind >= argc)
+  {
+    Error("missing drive argument\n");
+    return CGPT_FAILED;
+  }
+
+  params.drive_name = argv[optind];
+
+  if (!params.set_unique)
+  {
+    Error("no parameters were edited\n");
+    return CGPT_FAILED;
+  }
+
+  return CgptEdit(&params);
+}