Support appending vbmeta digest to id/fingerprint
Background in http://go/compatible-build-fingerprint. To uniquely
identify the mixed build, we plan to append the unique vbmeta digest
to ro.build.id.
If BOARD_USE_VBMETA_DIGTEST_IN_FINGERPRINT is true, the build system
will not set ro.build.id. Instead, init will set it at runtime, by
appending the digest to the legacy build id.
Bug: 186786987
Test: build and boot a device with new build id
Change-Id: Idea57df599bfd6eede760671e2555541f7dc3f21
diff --git a/init/property_service.cpp b/init/property_service.cpp
index fe3490d..6511bce 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -94,6 +94,12 @@
namespace android {
namespace init {
+constexpr auto FINGERPRINT_PROP = "ro.build.fingerprint";
+constexpr auto LEGACY_FINGERPRINT_PROP = "ro.build.legacy.fingerprint";
+constexpr auto ID_PROP = "ro.build.id";
+constexpr auto LEGACY_ID_PROP = "ro.build.legacy.id";
+constexpr auto VBMETA_DIGEST_PROP = "ro.boot.vbmeta.digest";
+constexpr auto DIGEST_SIZE_USED = 8;
static bool persistent_properties_loaded = false;
@@ -857,15 +863,33 @@
}
}
-// If the ro.build.fingerprint property has not been set, derive it from constituent pieces
-static void property_derive_build_fingerprint() {
- std::string build_fingerprint = GetProperty("ro.build.fingerprint", "");
- if (!build_fingerprint.empty()) {
+static void property_initialize_build_id() {
+ std::string build_id = GetProperty(ID_PROP, "");
+ if (!build_id.empty()) {
return;
}
+ std::string legacy_build_id = GetProperty(LEGACY_ID_PROP, "");
+ std::string vbmeta_digest = GetProperty(VBMETA_DIGEST_PROP, "");
+ if (vbmeta_digest.size() < DIGEST_SIZE_USED) {
+ LOG(ERROR) << "vbmeta digest size too small " << vbmeta_digest;
+ // Still try to set the id field in the unexpected case.
+ build_id = legacy_build_id;
+ } else {
+ // Derive the ro.build.id by appending the vbmeta digest to the base value.
+ build_id = legacy_build_id + "." + vbmeta_digest.substr(0, DIGEST_SIZE_USED);
+ }
+
+ std::string error;
+ auto res = PropertySet(ID_PROP, build_id, &error);
+ if (res != PROP_SUCCESS) {
+ LOG(ERROR) << "Failed to set " << ID_PROP << " to " << build_id;
+ }
+}
+
+static std::string ConstructBuildFingerprint(bool legacy) {
const std::string UNKNOWN = "unknown";
- build_fingerprint = GetProperty("ro.product.brand", UNKNOWN);
+ std::string build_fingerprint = GetProperty("ro.product.brand", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.product.name", UNKNOWN);
build_fingerprint += '/';
@@ -873,7 +897,10 @@
build_fingerprint += ':';
build_fingerprint += GetProperty("ro.build.version.release_or_codename", UNKNOWN);
build_fingerprint += '/';
- build_fingerprint += GetProperty("ro.build.id", UNKNOWN);
+
+ std::string build_id =
+ legacy ? GetProperty(LEGACY_ID_PROP, UNKNOWN) : GetProperty(ID_PROP, UNKNOWN);
+ build_fingerprint += build_id;
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.build.version.incremental", UNKNOWN);
build_fingerprint += ':';
@@ -881,13 +908,49 @@
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.build.tags", UNKNOWN);
- LOG(INFO) << "Setting property 'ro.build.fingerprint' to '" << build_fingerprint << "'";
+ return build_fingerprint;
+}
+
+// Derive the legacy build fingerprint if we overwrite the build id at runtime.
+static void property_derive_legacy_build_fingerprint() {
+ std::string legacy_build_fingerprint = GetProperty(LEGACY_FINGERPRINT_PROP, "");
+ if (!legacy_build_fingerprint.empty()) {
+ return;
+ }
+
+ // The device doesn't have a legacy build id, skipping the legacy fingerprint.
+ std::string legacy_build_id = GetProperty(LEGACY_ID_PROP, "");
+ if (legacy_build_id.empty()) {
+ return;
+ }
+
+ legacy_build_fingerprint = ConstructBuildFingerprint(true /* legacy fingerprint */);
+ LOG(INFO) << "Setting property '" << LEGACY_FINGERPRINT_PROP << "' to '"
+ << legacy_build_fingerprint << "'";
std::string error;
- uint32_t res = PropertySet("ro.build.fingerprint", build_fingerprint, &error);
+ uint32_t res = PropertySet(LEGACY_FINGERPRINT_PROP, legacy_build_fingerprint, &error);
if (res != PROP_SUCCESS) {
- LOG(ERROR) << "Error setting property 'ro.build.fingerprint': err=" << res << " (" << error
- << ")";
+ LOG(ERROR) << "Error setting property '" << LEGACY_FINGERPRINT_PROP << "': err=" << res
+ << " (" << error << ")";
+ }
+}
+
+// If the ro.build.fingerprint property has not been set, derive it from constituent pieces
+static void property_derive_build_fingerprint() {
+ std::string build_fingerprint = GetProperty("ro.build.fingerprint", "");
+ if (!build_fingerprint.empty()) {
+ return;
+ }
+
+ build_fingerprint = ConstructBuildFingerprint(false /* legacy fingerprint */);
+ LOG(INFO) << "Setting property '" << FINGERPRINT_PROP << "' to '" << build_fingerprint << "'";
+
+ std::string error;
+ uint32_t res = PropertySet(FINGERPRINT_PROP, build_fingerprint, &error);
+ if (res != PROP_SUCCESS) {
+ LOG(ERROR) << "Error setting property '" << FINGERPRINT_PROP << "': err=" << res << " ("
+ << error << ")";
}
}
@@ -1035,7 +1098,9 @@
}
property_initialize_ro_product_props();
+ property_initialize_build_id();
property_derive_build_fingerprint();
+ property_derive_legacy_build_fingerprint();
property_initialize_ro_cpu_abilist();
update_sys_usb_config();