3 files changed, 74 insertions, 6 deletions
diff --git a/bootloader_message/Android.bp b/bootloader_message/Android.bp
index 5cd21323c..450dad08b 100644
--- a/bootloader_message/Android.bp
+++ b/bootloader_message/Android.bp
@@ -14,9 +14,8 @@
 // limitations under the License.
 //
 
-cc_library {
-    name: "libbootloader_message",
-    recovery_available: true,
+cc_defaults {
+    name: "libbootloader_message_defaults",
     srcs: ["bootloader_message.cpp"],
     cflags: [
         "-Wall",
@@ -24,7 +23,25 @@ cc_library {
     ],
     shared_libs: [
         "libbase",
-        "libfs_mgr",
+    ],
+    static_libs: [
+        "libfstab",
     ],
     export_include_dirs: ["include"],
 }
+
+cc_library {
+    name: "libbootloader_message",
+    defaults: [
+        "libbootloader_message_defaults",
+    ],
+    recovery_available: true,
+}
+
+cc_library_static {
+    name: "libbootloader_message_vendor",
+    defaults: [
+        "libbootloader_message_defaults",
+    ],
+    vendor: true,
+}
diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index 8c1d63bdd..c1ebeaa82 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -21,6 +21,7 @@
 #include <string.h>
 
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <android-base/file.h>
@@ -32,7 +33,17 @@
 using android::fs_mgr::Fstab;
 using android::fs_mgr::ReadDefaultFstab;
 
+static std::string g_misc_device_for_test;
+
+// Exposed for test purpose.
+void SetMiscBlockDeviceForTest(std::string_view misc_device) {
+  g_misc_device_for_test = misc_device;
+}
+
 static std::string get_misc_blk_device(std::string* err) {
+  if (!g_misc_device_for_test.empty()) {
+    return g_misc_device_for_test;
+  }
   Fstab fstab;
   if (!ReadDefaultFstab(&fstab)) {
     *err = "failed to read default fstab";
@@ -228,6 +239,37 @@ bool write_wipe_package(const std::string& package_data, std::string* err) {
                               WIPE_PACKAGE_OFFSET_IN_MISC, err);
 }
 
+static bool OffsetAndSizeInVendorSpace(size_t offset, size_t size) {
+  auto total_size = WIPE_PACKAGE_OFFSET_IN_MISC - VENDOR_SPACE_OFFSET_IN_MISC;
+  return size <= total_size && offset <= total_size - size;
+}
+
+bool ReadMiscPartitionVendorSpace(void* data, size_t size, size_t offset, std::string* err) {
+  if (!OffsetAndSizeInVendorSpace(offset, size)) {
+    *err = android::base::StringPrintf("Out of bound read (offset %zu size %zu)", offset, size);
+    return false;
+  }
+  auto misc_blk_device = get_misc_blk_device(err);
+  if (misc_blk_device.empty()) {
+    return false;
+  }
+  return read_misc_partition(data, size, misc_blk_device, VENDOR_SPACE_OFFSET_IN_MISC + offset,
+                             err);
+}
+
+bool WriteMiscPartitionVendorSpace(const void* data, size_t size, size_t offset, std::string* err) {
+  if (!OffsetAndSizeInVendorSpace(offset, size)) {
+    *err = android::base::StringPrintf("Out of bound write (offset %zu size %zu)", offset, size);
+    return false;
+  }
+  auto misc_blk_device = get_misc_blk_device(err);
+  if (misc_blk_device.empty()) {
+    return false;
+  }
+  return write_misc_partition(data, size, misc_blk_device, VENDOR_SPACE_OFFSET_IN_MISC + offset,
+                              err);
+}
+
 extern "C" bool write_reboot_bootloader(void) {
   std::string err;
   return write_reboot_bootloader(&err);
diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h
index 95c19ae54..95dd8f4c9 100644
--- a/bootloader_message/include/bootloader_message/bootloader_message.h
+++ b/bootloader_message/include/bootloader_message/bootloader_message.h
@@ -28,8 +28,9 @@
 // 16K - 64K    Used by uncrypt and recovery to store wipe_package for A/B devices
 // Note that these offsets are admitted by bootloader,recovery and uncrypt, so they
 // are not configurable without changing all of them.
-static const size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0;
-static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;
+constexpr size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0;
+constexpr size_t VENDOR_SPACE_OFFSET_IN_MISC = 2 * 1024;
+constexpr size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;
 
 /* Bootloader Message (2-KiB)
  *
@@ -228,6 +229,14 @@ bool read_wipe_package(std::string* package_data, size_t size, std::string* err)
 // Write the wipe package into BCB (to offset WIPE_PACKAGE_OFFSET_IN_MISC).
 bool write_wipe_package(const std::string& package_data, std::string* err);
 
+// Reads data from the vendor space in /misc partition, with the given offset and size. Note that
+// offset is in relative to the start of vendor space.
+bool ReadMiscPartitionVendorSpace(void* data, size_t size, size_t offset, std::string* err);
+
+// Writes the given data to the vendor space in /misc partition, at the given offset. Note that
+// offset is in relative to the start of the vendor space.
+bool WriteMiscPartitionVendorSpace(const void* data, size_t size, size_t offset, std::string* err);
+
 #else
 
 #include <stdbool.h>