BootParameters: Use proto for disk io.

Use proto for disk usage.

Bug: 79932027
Test: Ran through the following scenarios-
- RebootActivity parses previous boot parameters; sets next as expected.
- Push old parameters to device and ensured bootanimations reads it and
saves new format (serialized proto) that can be read in userspace
(RebootActivity).
- Unit tests pass.

Change-Id: I98aefb7a832c985d5061ee80ab85a4523f067641
diff --git a/cmds/bootanimation/iot/BootParameters.cpp b/cmds/bootanimation/iot/BootParameters.cpp
index 2cf1c19..30a9b28 100644
--- a/cmds/bootanimation/iot/BootParameters.cpp
+++ b/cmds/bootanimation/iot/BootParameters.cpp
@@ -22,10 +22,13 @@
 #include <fcntl.h>
 
 #include <android-base/file.h>
+#include <json/json.h>
 #include <utils/Log.h>
 
 using android::base::ReadFileToString;
 using android::base::RemoveFileIfExists;
+using android::base::WriteStringToFile;
+using Json::ArrayIndex;
 using Json::Reader;
 using Json::Value;
 
@@ -33,23 +36,34 @@
 
 namespace {
 
-// Keys for supporting a silent boot and user-defined BootAction parameters.
-constexpr const char *kKeySilentBoot = "silent_boot";
-constexpr const char* kKeyParams = "params";
+// Keys for deprecated parameters. Devices that OTA from N to O and that used
+// the hidden BootParameters API will store these in the JSON blob. To support
+// the transition from N to O, these keys are mapped to the new parameters.
+constexpr const char *kKeyLegacyVolume = "volume";
+constexpr const char *kKeyLegacyAnimationsDisabled = "boot_animation_disabled";
+constexpr const char *kKeyLegacyParamNames = "param_names";
+constexpr const char *kKeyLegacyParamValues = "param_values";
 
-constexpr const char* kNextBootFile = "/data/misc/bootanimation/next_boot.json";
-constexpr const char* kLastBootFile = "/data/misc/bootanimation/last_boot.json";
+constexpr const char *kNextBootFile = "/data/misc/bootanimation/next_boot.proto";
+constexpr const char *kLastBootFile = "/data/misc/bootanimation/last_boot.proto";
 
-void swapBootConfigs() {
-    // rename() will fail if next_boot.json doesn't exist, so delete
-    // last_boot.json manually first.
+constexpr const char *kLegacyNextBootFile = "/data/misc/bootanimation/next_boot.json";
+constexpr const char *kLegacyLastBootFile = "/data/misc/bootanimation/last_boot.json";
+
+void removeLegacyFiles() {
     std::string err;
-    if (!RemoveFileIfExists(kLastBootFile, &err))
-        ALOGE("Unable to delete last boot file: %s", err.c_str());
+    if (!RemoveFileIfExists(kLegacyLastBootFile, &err)) {
+        ALOGW("Unable to delete %s: %s", kLegacyLastBootFile, err.c_str());
+    }
 
-    if (rename(kNextBootFile, kLastBootFile) && errno != ENOENT)
-        ALOGE("Unable to swap boot files: %s", strerror(errno));
+    err.clear();
+    if (!RemoveFileIfExists(kLegacyNextBootFile, &err)) {
+        ALOGW("Unable to delete %s: %s", kLegacyNextBootFile, err.c_str());
+    }
+}
 
+void createNextBootFile() {
+    errno = 0;
     int fd = open(kNextBootFile, O_CREAT, DEFFILEMODE);
     if (fd == -1) {
         ALOGE("Unable to create next boot file: %s", strerror(errno));
@@ -64,54 +78,120 @@
 
 }  // namespace
 
+// Renames the 'next' boot file to the 'last' file and reads its contents.
+bool BootParameters::swapAndLoadBootConfigContents(const char *lastBootFile,
+                                                   const char *nextBootFile,
+                                                   std::string *contents) {
+    if (!ReadFileToString(nextBootFile, contents)) {
+        RemoveFileIfExists(lastBootFile);
+        return false;
+    }
+
+    errno = 0;
+    if (rename(nextBootFile, lastBootFile) && errno != ENOENT)
+        ALOGE("Unable to swap boot files: %s", strerror(errno));
+
+    return true;
+}
+
 BootParameters::BootParameters() {
-    swapBootConfigs();
     loadParameters();
 }
 
-void BootParameters::loadParameters() {
-    std::string contents;
-    if (!ReadFileToString(kLastBootFile, &contents)) {
-        if (errno != ENOENT)
-            ALOGE("Unable to read from %s: %s", kLastBootFile, strerror(errno));
+// Saves the boot parameters state to disk so the framework can read it.
+void BootParameters::storeParameters() {
+    errno = 0;
+    if (!WriteStringToFile(mProto.SerializeAsString(), kLastBootFile)) {
+        ALOGE("Failed to write boot parameters to %s: %s", kLastBootFile, strerror(errno));
+    }
 
+    // WriteStringToFile sets the file permissions to 0666, but these are not
+    // honored by the system.
+    errno = 0;
+    if (chmod(kLastBootFile, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)) {
+        ALOGE("Failed to set permissions for %s: %s", kLastBootFile, strerror(errno));
+    }
+}
+
+// Load the boot parameters from disk, try the old location and format if the
+// file does not exist. Note:
+// - Parse errors result in defaults being used (a normal boot).
+// - Legacy boot parameters default to a silent boot.
+void BootParameters::loadParameters() {
+    // Precedence is given to the new file format (.proto).
+    std::string contents;
+    if (swapAndLoadBootConfigContents(kLastBootFile, kNextBootFile, &contents)) {
+        parseBootParameters(contents);
+    } else if (swapAndLoadBootConfigContents(kLegacyLastBootFile, kLegacyNextBootFile, &contents)) {
+        parseLegacyBootParameters(contents);
+        storeParameters();
+        removeLegacyFiles();
+    }
+
+    createNextBootFile();
+}
+
+void BootParameters::parseBootParameters(const std::string &contents) {
+    if (!mProto.ParseFromString(contents)) {
+        ALOGW("Failed to parse parameters from %s", kLastBootFile);
         return;
     }
 
-    loadParameters(contents);
+    loadStateFromProto();
 }
 
-// If the boot parameters -
-// - File is missing, we assume a normal, non-silent boot.
-// - Are well-formed, initially assume a normal, non-silent boot and parse.
-void BootParameters::loadParameters(const std::string& raw_json) {
-  if (!Reader().parse(raw_json, mJson)) {
-    return;
-  }
-
-  parseBootParameters();
-}
-
-void BootParameters::parseBootParameters() {
-    // A missing key returns a safe, missing value.
-    // Ignore invalid or missing JSON parameters.
-    Value &jsonValue = mJson[kKeySilentBoot];
-    if (jsonValue.isBool()) {
-        mIsSilentBoot = jsonValue.asBool();
+// Parses the JSON in the proto.
+void BootParameters::parseLegacyBootParameters(const std::string &contents) {
+    Value json;
+    if (!Reader().parse(contents, json)) {
+        ALOGW("Failed to parse parameters from %s", kLegacyLastBootFile);
+        return;
     }
 
-    jsonValue = mJson[kKeyParams];
-    if (jsonValue.isObject()) {
-        // getMemberNames returns a copy of the keys which must be stored.
-        mKeys = jsonValue.getMemberNames();
-        for (auto &key : mKeys) {
-            Value &value = jsonValue[key];
-            if (value.isString()) {
-                mParameters.push_back(
-                    {.key = key.c_str(), .value = value.asCString()});
+    int volume = 0;
+    bool bootAnimationDisabled = true;
+
+    Value &jsonValue = json[kKeyLegacyVolume];
+    if (jsonValue.isIntegral()) {
+        volume = jsonValue.asInt();
+    }
+
+    jsonValue = json[kKeyLegacyAnimationsDisabled];
+    if (jsonValue.isIntegral()) {
+        bootAnimationDisabled = jsonValue.asInt() == 1;
+    }
+
+    // Assume a silent boot unless all of the following are true -
+    // 1. The volume is neither 0 nor -1000 (the legacy default value).
+    // 2. The boot animations are explicitly enabled.
+    // Note: brightness was never used.
+    mProto.set_silent_boot((volume == 0) || (volume == -1000) || bootAnimationDisabled);
+
+    Value &keys = json[kKeyLegacyParamNames];
+    Value &values = json[kKeyLegacyParamValues];
+    if (keys.isArray() && values.isArray() && (keys.size() == values.size())) {
+        for (ArrayIndex i = 0; i < keys.size(); ++i) {
+            auto &key = keys[i];
+            auto &value = values[i];
+            if (key.isString() && value.isString()) {
+                auto userParameter = mProto.add_user_parameter();
+                userParameter->set_key(key.asString());
+                userParameter->set_value(value.asString());
             }
         }
     }
+
+    loadStateFromProto();
+}
+
+void BootParameters::loadStateFromProto() {
+    // A missing key returns a safe, default value.
+    // Ignore invalid or missing parameters.
+    mIsSilentBoot = mProto.silent_boot();
+
+    for (const auto &param : mProto.user_parameter()) {
+        mParameters.push_back({.key = param.key().c_str(), .value = param.value().c_str()});
+    }
 }
 
 }  // namespace android