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-rw-r--r--cgpt/cgpt_prioritize.c217
1 files changed, 217 insertions, 0 deletions
diff --git a/cgpt/cgpt_prioritize.c b/cgpt/cgpt_prioritize.c
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+++ b/cgpt/cgpt_prioritize.c
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+// Copyright (c) 2012 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 <string.h>
+
+#include "cgptlib_internal.h"
+#include "cgpt_params.h"
+
+//////////////////////////////////////////////////////////////////////////////
+// We need a sorted list of priority groups, where each element in the list
+// contains an unordered list of GPT partition numbers.
+
+#define MAX_GROUPS 17 // 0-15, plus one "higher"
+
+typedef struct {
+ int priority; // priority of this group
+ int num_parts; // number of partitions in this group
+ uint32_t *part; // array of partitions in this group
+} group_t;
+
+typedef struct {
+ int max_parts; // max number of partitions in any group
+ int num_groups; // number of non-empty groups
+ group_t group[MAX_GROUPS]; // array of groups
+} group_list_t;
+
+
+static group_list_t *NewGroupList(int max_p) {
+ int i;
+ group_list_t *gl = (group_list_t *)malloc(sizeof(group_list_t));
+ require(gl);
+ gl->max_parts = max_p;
+ gl->num_groups = 0;
+ // reserve space for the maximum number of partitions in every group
+ for (i=0; i<MAX_GROUPS; i++) {
+ gl->group[i].priority = -1;
+ gl->group[i].num_parts = 0;
+ gl->group[i].part = (uint32_t *)malloc(sizeof(uint32_t) * max_p);
+ require(gl->group[i].part);
+ }
+
+ return gl;
+}
+
+static void FreeGroups(group_list_t *gl) {
+ int i;
+ for (i=0; i<MAX_GROUPS; i++)
+ free(gl->group[i].part);
+ free(gl);
+}
+
+static void AddToGroup(group_list_t *gl, int priority, int partition) {
+ int i;
+ // See if I've already got a group with this priority
+ for (i=0; i<gl->num_groups; i++)
+ if (gl->group[i].priority == priority)
+ break;
+ if (i == gl->num_groups) {
+ // no, add a group
+ require(i < MAX_GROUPS);
+ gl->num_groups++;
+ gl->group[i].priority = priority;
+ }
+ // add the partition to it
+ int j = gl->group[i].num_parts;
+ gl->group[i].part[j] = partition;
+ gl->group[i].num_parts++;
+}
+
+static void ChangeGroup(group_list_t *gl, int old_priority, int new_priority) {
+ int i;
+ for (i=0; i<gl->num_groups; i++)
+ if (gl->group[i].priority == old_priority) {
+ gl->group[i].priority = new_priority;
+ break;
+ }
+}
+
+static void SortGroups(group_list_t *gl) {
+ int i, j;
+ group_t tmp;
+
+ // straight insertion sort is fast enough
+ for (i=1; i<gl->num_groups; i++) {
+ tmp = gl->group[i];
+ for (j=i; j && (gl->group[j-1].priority < tmp.priority); j--)
+ gl->group[j] = gl->group[j-1];
+ gl->group[j] = tmp;
+ }
+}
+
+int cgpt_prioritize(CgptPrioritizeParams *params) {
+ struct drive drive;
+
+ int priority;
+
+ int gpt_retval;
+ GptEntry *entry;
+ uint32_t index;
+ uint32_t max_part;
+ int num_kernels;
+ int i,j;
+ group_list_t *groups;
+
+ if (params == NULL)
+ return CGPT_FAILED;
+
+ if (CGPT_OK != DriveOpen(params->driveName, &drive))
+ return CGPT_FAILED;
+
+ if (GPT_SUCCESS != (gpt_retval = GptSanityCheck(&drive.gpt))) {
+ Error("GptSanityCheck() returned %d: %s\n",
+ gpt_retval, GptError(gpt_retval));
+ return CGPT_FAILED;
+ }
+
+ max_part = GetNumberOfEntries(&drive.gpt);
+
+ if (params->set_partition) {
+ if (params->set_partition < 1 || params->set_partition > max_part) {
+ Error("invalid partition number: %d (must be between 1 and %d\n",
+ params->set_partition, max_part);
+ goto bad;
+ }
+ index = params->set_partition - 1;
+ // it must be a kernel
+ entry = GetEntry(&drive.gpt, PRIMARY, index);
+ if (!GuidEqual(&entry->type, &guid_chromeos_kernel)) {
+ Error("partition %d is not a ChromeOS kernel\n", params->set_partition);
+ goto bad;
+ }
+ }
+
+ // How many kernel partitions do I have?
+ num_kernels = 0;
+ for (i = 0; i < max_part; i++) {
+ entry = GetEntry(&drive.gpt, PRIMARY, i);
+ if (GuidEqual(&entry->type, &guid_chromeos_kernel))
+ num_kernels++;
+ }
+
+ if (num_kernels) {
+ // Determine the current priority groups
+ groups = NewGroupList(num_kernels);
+ for (i = 0; i < max_part; i++) {
+ entry = GetEntry(&drive.gpt, PRIMARY, i);
+ if (!GuidEqual(&entry->type, &guid_chromeos_kernel))
+ continue;
+
+ priority = GetPriority(&drive.gpt, PRIMARY, i);
+
+ // Is this partition special?
+ if (params->set_partition && (i+1 == params->set_partition)) {
+ params->orig_priority = priority; // remember the original priority
+ if (params->set_friends)
+ AddToGroup(groups, priority, i); // we'll move them all later
+ else
+ AddToGroup(groups, 99, i); // move only this one
+ } else {
+ AddToGroup(groups, priority, i); // just remember
+ }
+ }
+
+ // If we're including friends, then change the original group priority
+ if (params->set_partition && params->set_friends) {
+ ChangeGroup(groups, params->orig_priority, 99);
+ }
+
+ // Sorting gives the new order. Now we just need to reassign the
+ // priorities.
+ SortGroups(groups);
+
+ // We'll never lower anything to zero, so if the last group is priority zero
+ // we can ignore it.
+ i = groups->num_groups;
+ if (groups->group[i-1].priority == 0)
+ groups->num_groups--;
+
+ // Where do we start?
+ if (params->max_priority)
+ priority = params->max_priority;
+ else
+ priority = groups->num_groups > 15 ? 15 : groups->num_groups;
+
+ // Figure out what the new values should be
+ for (i=0; i<groups->num_groups; i++) {
+ groups->group[i].priority = priority;
+ if (priority > 1)
+ priority--;
+ }
+
+ // Now apply the ranking to the GPT
+ for (i=0; i<groups->num_groups; i++)
+ for (j=0; j<groups->group[i].num_parts; j++)
+ SetPriority(&drive.gpt, PRIMARY,
+ groups->group[i].part[j], groups->group[i].priority);
+
+ FreeGroups(groups);
+ }
+
+ // Write it all out
+ RepairEntries(&drive.gpt, MASK_PRIMARY);
+ RepairHeader(&drive.gpt, MASK_PRIMARY);
+
+ drive.gpt.modified |= (GPT_MODIFIED_HEADER1 | GPT_MODIFIED_ENTRIES1 |
+ GPT_MODIFIED_HEADER2 | GPT_MODIFIED_ENTRIES2);
+ UpdateCrc(&drive.gpt);
+
+ return DriveClose(&drive, 1);
+
+bad:
+ (void) DriveClose(&drive, 0);
+ return CGPT_FAILED;
+}
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