1 files changed, 193 insertions, 0 deletions
diff --git a/bootctrl/1.2/GptUtils.cpp b/bootctrl/1.2/GptUtils.cpp
new file mode 100644
index 0000000..25088e7
--- /dev/null
+++ b/bootctrl/1.2/GptUtils.cpp
@@ -0,0 +1,193 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "bootcontrolhal"
+
+#include "GptUtils.h"
+
+#include <android-base/file.h>
+#include <errno.h>
+#include <linux/fs.h>
+#include <log/log.h>
+#include <zlib.h>
+
+namespace android {
+namespace hardware {
+namespace boot {
+namespace V1_2 {
+namespace implementation {
+
+namespace {
+
+static int ValidateGptHeader(gpt_header *gpt) {
+    if (gpt->signature != GPT_SIGNATURE) {
+        ALOGE("invalid gpt signature 0x%lx\n", gpt->signature);
+        return -1;
+    }
+
+    if (gpt->header_size != sizeof(gpt_header)) {
+        ALOGE("invalid gpt header size %u\n", gpt->header_size);
+        return -1;
+    }
+
+    if (gpt->entry_size != sizeof(gpt_entry)) {
+        ALOGE("invalid gpt entry size %u\n", gpt->entry_size);
+        return -1;
+    }
+
+    return 0;
+}
+
+}  // namespace
+
+GptUtils::GptUtils(const std::string dev_path) : dev_path(dev_path), fd(0) {}
+
+int GptUtils::Load(void) {
+    fd = open(dev_path.c_str(), O_RDWR);
+    if (fd < 0) {
+        ALOGE("failed to open block dev %s, %d\n", dev_path.c_str(), errno);
+        return -1;
+    }
+
+    int ret = ioctl(fd, BLKSSZGET, &block_size);
+    if (ret < 0) {
+        ALOGE("failed to get block size %d\n", errno);
+        return -1;
+    }
+
+    // read primary header
+    lseek64(fd, block_size, SEEK_SET);
+    ret = read(fd, &gpt_primary, sizeof gpt_primary);
+    if (ret < 0) {
+        ALOGE("failed to read gpt primary header %d\n", errno);
+        return -1;
+    }
+
+    if (ValidateGptHeader(&gpt_primary)) {
+        ALOGE("error validating gpt header\n");
+        return -1;
+    }
+
+    // read partition entries
+    entry_array.resize(gpt_primary.entry_count);
+    uint32_t entries_size = gpt_primary.entry_size * gpt_primary.entry_count;
+    lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
+    ret = read(fd, entry_array.data(), entries_size);
+    if (ret < 0) {
+        ALOGE("failed to read gpt partition entries %d\n", errno);
+        return -1;
+    }
+
+    // read gpt back header
+    lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
+    ret = read(fd, &gpt_backup, sizeof gpt_backup);
+    if (ret < 0) {
+        ALOGE("failed to read gpt backup header %d\n", errno);
+        return -1;
+    }
+
+    if (ValidateGptHeader(&gpt_backup)) {
+        ALOGW("error validating gpt backup\n");  // just warn about it, not fail
+    }
+
+    // Create map <partition name, gpt_entry pointer>
+    auto get_name = [](const uint16_t *efi_name) {
+        char name[37] = {};
+        for (int i = 0; efi_name[i] && i < sizeof name - 1; ++i) name[i] = efi_name[i];
+        return std::string(name);
+    };
+
+    for (auto const &e : entry_array) {
+        if (e.name[0] == 0)
+            break;  // stop at the first partition with no name
+        std::string s = get_name(e.name);
+        entries[s] = const_cast<gpt_entry *>(&e);
+    }
+
+    return 0;
+}
+
+gpt_entry *GptUtils::GetPartitionEntry(std::string name) {
+    return entries.find(name) != entries.end() ? entries[name] : nullptr;
+}
+
+int GptUtils::Sync(void) {
+    if (!fd)
+        return -1;
+
+    // calculate crc and check if we need to update gpt
+    gpt_primary.entries_crc32 = crc32(0, reinterpret_cast<uint8_t *>(entry_array.data()),
+                                      entry_array.size() * sizeof(gpt_entry));
+
+    // save old crc
+    uint32_t crc = gpt_primary.crc32;
+    gpt_primary.crc32 = 0;
+
+    gpt_primary.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_primary), sizeof gpt_primary);
+    if (crc == gpt_primary.crc32)
+        return 0;  // nothing to do (no changes)
+
+    ALOGI("updating GPT\n");
+
+    lseek64(fd, block_size * gpt_primary.current_lba, SEEK_SET);
+    int ret = write(fd, &gpt_primary, sizeof gpt_primary);
+    if (ret < 0) {
+        ALOGE("failed to write gpt primary header %d\n", errno);
+        return -1;
+    }
+
+    lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
+    ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
+    if (ret < 0) {
+        ALOGE("failed to write gpt partition entries %d\n", errno);
+        return -1;
+    }
+
+    // update GPT backup entries and backup
+    lseek64(fd, block_size * gpt_backup.start_lba, SEEK_SET);
+    ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
+    if (ret < 0) {
+        ALOGE("failed to write gpt backup partition entries %d\n", errno);
+        return -1;
+    }
+
+    gpt_backup.entries_crc32 = gpt_primary.entries_crc32;
+    gpt_backup.crc32 = 0;
+    gpt_backup.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_backup), sizeof gpt_backup);
+    lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
+    ret = write(fd, &gpt_backup, sizeof gpt_backup);
+    if (ret < 0) {
+        ALOGE("failed to write gpt backup header %d\n", errno);
+        return -1;
+    }
+
+    fsync(fd);
+
+    return 0;
+}
+
+GptUtils::~GptUtils() {
+    if (fd) {
+        Sync();
+        close(fd);
+    }
+}
+
+}  // namespace implementation
+}  // namespace V1_2
+}  // namespace boot
+}  // namespace hardware
+}  // namespace android