From 92116e4129812eccb32d7a20208e03be7ee2ec75 Mon Sep 17 00:00:00 2001
From: Nikita Ioffe <ioffe@google.com>
Date: Tue, 31 Mar 2020 01:28:35 +0100
Subject: [PATCH] Properly fail userspace reboot if it's not supported

Previously, after `adb reboot userspace` is called on a device that
doesn't suppor it, init would've logged an error and quietly exit the
shutdown sequence. This was leaving adb handing forever.

With this approach, init will fail setprop
"sys.powerctl=reboot,userspace" in case userspace reboot is not
supported.

Test: adb root
Test: adb setprop init.userspace_reboot.is_supported 0
Test: adb reboot userspace
Test: atest CtsInitTestCases
Bug: 146639622
Change-Id: I1264078f53ed3ff54638c7f3b6846b7437f98ee5
---
 init/property_service.cpp      |  6 ++++++
 init/property_service_test.cpp | 16 ++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/init/property_service.cpp b/init/property_service.cpp
index 655b8deef..842b2e5b7 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -47,6 +47,7 @@
 #include <thread>
 #include <vector>
 
+#include <InitProperties.sysprop.h>
 #include <android-base/chrono_utils.h>
 #include <android-base/file.h>
 #include <android-base/logging.h>
@@ -85,6 +86,7 @@ using android::properties::BuildTrie;
 using android::properties::ParsePropertyInfoFile;
 using android::properties::PropertyInfoAreaFile;
 using android::properties::PropertyInfoEntry;
+using android::sysprop::InitProperties::is_userspace_reboot_supported;
 
 namespace android {
 namespace init {
@@ -492,6 +494,10 @@ uint32_t HandlePropertySet(const std::string& name, const std::string& value,
         if (!value.empty()) {
             DebugRebootLogging();
         }
+        if (value == "reboot,userspace" && !is_userspace_reboot_supported().value_or(false)) {
+            *error = "Userspace reboot is not supported by this device";
+            return PROP_ERROR_INVALID_VALUE;
+        }
     }
 
     // If a process other than init is writing a non-empty value, it means that process is
diff --git a/init/property_service_test.cpp b/init/property_service_test.cpp
index 0f4cd0d1f..c6dcfa257 100644
--- a/init/property_service_test.cpp
+++ b/init/property_service_test.cpp
@@ -22,8 +22,10 @@
 #include <sys/_system_properties.h>
 
 #include <android-base/properties.h>
+#include <android-base/scopeguard.h>
 #include <gtest/gtest.h>
 
+using android::base::GetProperty;
 using android::base::SetProperty;
 
 namespace android {
@@ -74,5 +76,19 @@ TEST(property_service, non_utf8_value) {
     EXPECT_TRUE(SetProperty("property_service_utf8_test", "\xF0\x90\x80\x80"));
 }
 
+TEST(property_service, userspace_reboot_not_supported) {
+    if (getuid() != 0) {
+        GTEST_SKIP() << "Skipping test, must be run as root.";
+        return;
+    }
+    const std::string original_value = GetProperty("init.userspace_reboot.is_supported", "");
+    auto guard = android::base::make_scope_guard([&original_value]() {
+        SetProperty("init.userspace_reboot.is_supported", original_value);
+    });
+
+    ASSERT_TRUE(SetProperty("init.userspace_reboot.is_supported", "false"));
+    EXPECT_FALSE(SetProperty("sys.powerctl", "reboot,userspace"));
+}
+
 }  // namespace init
 }  // namespace android