bootctrl: Fix vendor space usage to not conflict with theme data.

Pixel writes theme data to the first bytes of vendor space, and reserves
the first 32x32 bytes for other such flags (such as the SOTA flag). To
avoid conflicts, instead use new AOSP-generic methods in
bootloader_message and libboot_control.

Bug: 139156011
Test: manual test
Change-Id: I7f31847acc21a0eeb46640cb9ed70be2a3f9531c

1 files changed, 11 insertions, 107 deletions

diff --git a/bootctrl/BootControlShared.cpp b/bootctrl/BootControlShared.cpp
index 193ddea..125bec4 100644
--- a/bootctrl/BootControlShared.cpp
+++ b/bootctrl/BootControlShared.cpp
@@ -20,6 +20,7 @@
 #include <android-base/logging.h>
 #include <android-base/unique_fd.h>
 #include <bootloader_message/bootloader_message.h>
+#include <libboot_control/libboot_control.h>
 
 #include "BootControlShared.h"
 
@@ -29,124 +30,27 @@ namespace boot {
 namespace V1_1 {
 namespace implementation {
 
-using android::base::unique_fd;
+using android::bootable::GetMiscVirtualAbMergeStatus;
+using android::bootable::InitMiscVirtualAbMessageIfNeeded;
+using android::bootable::SetMiscVirtualAbMergeStatus;
 using android::hardware::boot::V1_1::MergeStatus;
 
-constexpr off_t kBootloaderControlOffset = offsetof(bootloader_message_ab, slot_suffix);
+BootControlShared::BootControlShared() {}
 
-static uint32_t CRC32(const uint8_t *buf, size_t size) {
-    static uint32_t crc_table[256];
-
-    // Compute the CRC-32 table only once.
-    if (!crc_table[1]) {
-        for (uint32_t i = 0; i < 256; ++i) {
-            uint32_t crc = i;
-            for (uint32_t j = 0; j < 8; ++j) {
-                uint32_t mask = -(crc & 1);
-                crc = (crc >> 1) ^ (0xEDB88320 & mask);
-            }
-            crc_table[i] = crc;
-        }
-    }
-
-    uint32_t ret = -1;
-    for (size_t i = 0; i < size; ++i) {
-        ret = (ret >> 8) ^ crc_table[(ret ^ buf[i]) & 0xFF];
-    }
-
-    return ~ret;
-}
-
-uint32_t ComputeChecksum(const bootloader_control *boot_ctrl) {
-    return CRC32(reinterpret_cast<const uint8_t *>(boot_ctrl),
-                 offsetof(bootloader_control, crc32_le));
-}
-
-static bool LoadUpdateState(const std::string &misc_device, bootloader_control *buffer) {
-    unique_fd fd(open(misc_device.c_str(), O_RDONLY));
-    if (fd < 0) {
-        PLOG(ERROR) << "failed to open " << misc_device;
-        return false;
-    }
-    if (lseek(fd, kBootloaderControlOffset, SEEK_SET) != kBootloaderControlOffset) {
-        PLOG(ERROR) << "failed to lseek " << misc_device;
-        return false;
-    }
-    if (!android::base::ReadFully(fd, buffer, sizeof(bootloader_control))) {
-        PLOG(ERROR) << "failed to read " << misc_device;
-        return false;
-    }
-    return true;
-}
-
-static bool SaveUpdateState(const std::string &misc_device, bootloader_control *buffer) {
-    unique_fd fd(open(misc_device.c_str(), O_WRONLY | O_SYNC));
-    if (fd < 0) {
-        PLOG(ERROR) << "failed to open " << misc_device;
-        return false;
-    }
-    if (lseek(fd, kBootloaderControlOffset, SEEK_SET) != kBootloaderControlOffset) {
-        PLOG(ERROR) << "failed to lseek " << misc_device;
-        return false;
-    }
-
-    buffer->crc32_le = ComputeChecksum(buffer);
-    if (!android::base::WriteFully(fd, buffer, sizeof(bootloader_control))) {
-        PLOG(ERROR) << "failed to write " << misc_device;
-        return false;
-    }
-    return true;
-}
-
-BootControlShared::BootControlShared() {
-    std::string err;
-    misc_device_ = get_bootloader_message_blk_device(&err);
-    if (misc_device_.empty()) {
-        LOG(FATAL) << "Unable to locate misc device: " << err;
-    }
-
-    bootloader_control control;
-    if (!LoadUpdateState(misc_device_, &control)) {
-        LOG(FATAL) << "Unable to read update state from misc partition";
-    }
-    uint32_t computed_crc32 = ComputeChecksum(&control);
-
-    bool initialize = false;
-    if (computed_crc32 != control.crc32_le) {
-        LOG(WARNING) << "Invalid boot control found, expected CRC32 0x" << std::hex
-                     << computed_crc32 << " but found 0x" << std::hex << control.crc32_le;
-        initialize = true;
-    } else if (control.magic != BOOT_CTRL_MAGIC) {
-        LOG(WARNING) << "Invalid boot control magic, " << std::hex << control.magic;
-        initialize = true;
-    }
-    if (initialize) {
-        LOG(WARNING) << "Re-initializing misc.";
-
-        // We only use the |merge_status| field of this structure.
-        memset(&control, 0, sizeof(control));
-        control.magic = BOOT_CTRL_MAGIC;
-        control.version = BOOT_CTRL_VERSION;
-        control.merge_status = static_cast<uint8_t>(MergeStatus::NONE);
-        SaveUpdateState(misc_device_, &control);
-    }
+bool BootControlShared::Init() {
+    return InitMiscVirtualAbMessageIfNeeded();
 }
 
 Return<bool> BootControlShared::setSnapshotMergeStatus(MergeStatus status) {
-    bootloader_control control;
-    if (!LoadUpdateState(misc_device_, &control)) {
-        return false;
-    }
-    control.merge_status = static_cast<uint8_t>(status);
-    return SaveUpdateState(misc_device_, &control);
+    return SetMiscVirtualAbMergeStatus(getCurrentSlot(), status);
 }
 
 Return<MergeStatus> BootControlShared::getSnapshotMergeStatus() {
-    bootloader_control control;
-    if (!LoadUpdateState(misc_device_, &control)) {
+    MergeStatus status;
+    if (!GetMiscVirtualAbMergeStatus(getCurrentSlot(), &status)) {
         return MergeStatus::UNKNOWN;
     }
-    return static_cast<MergeStatus>(control.merge_status);
+    return status;
 }
 
 }  // namespace implementation