Switch /data/misc/reboot/last_reboot_reason to persistent property

Switch from /data/misc/reboot/last_reboot_reason to persistent
Android property persist.sys.boot.reason for indicating why the
device is rebooted or shutdown.

persist.sys.boot.reason has a standard as outlined in b/63736262 and
the associated investigation. Made adjustments to the values so that
we did not create a problem even before we started. Compliance is
part of the tests in boot_reason_test.sh.

Test: system/core/bootstat/boot_reason_test.sh
Bug: 64687998
Change-Id: I812c55a12faf7cb7ff92101009be058ad9958d07

init/reboot.cpp

@@ -347,14 +347,10 @@ void DoReboot(unsigned int cmd, const std::string& reason, const std::string& re
     Timer t;
     LOG(INFO) << "Reboot start, reason: " << reason << ", rebootTarget: " << rebootTarget;
 
-    android::base::WriteStringToFile(StringPrintf("%s\n", reason.c_str()), LAST_REBOOT_REASON_FILE,
-                                     S_IRUSR | S_IWUSR, AID_SYSTEM, AID_SYSTEM);
+    property_set(LAST_REBOOT_REASON_PROPERTY, reason.c_str());
+    sync();
 
-    bool is_thermal_shutdown = false;
-    if (cmd == ANDROID_RB_THERMOFF) {
-        is_thermal_shutdown = true;
-        runFsck = false;
-    }
+    bool is_thermal_shutdown = cmd == ANDROID_RB_THERMOFF;
 
     auto shutdown_timeout = 0ms;
     if (!SHUTDOWN_ZERO_TIMEOUT) {
@@ -476,10 +472,15 @@ bool HandlePowerctlMessage(const std::string& command) {
         command_invalid = true;
     } else if (cmd_params[0] == "shutdown") {
         cmd = ANDROID_RB_POWEROFF;
-        if (cmd_params.size() == 2 && cmd_params[1] == "userrequested") {
-            // The shutdown reason is PowerManager.SHUTDOWN_USER_REQUESTED.
-            // Run fsck once the file system is remounted in read-only mode.
-            run_fsck = true;
+        if (cmd_params.size() == 2) {
+            if (cmd_params[1] == "userrequested") {
+                // The shutdown reason is PowerManager.SHUTDOWN_USER_REQUESTED.
+                // Run fsck once the file system is remounted in read-only mode.
+                run_fsck = true;
+            } else if (cmd_params[1] == "thermal") {
+                // run_fsck is false to avoid delay
+                cmd = ANDROID_RB_THERMOFF;
+            }
         }
     } else if (cmd_params[0] == "reboot") {
         cmd = ANDROID_RB_RESTART2;
@@ -495,14 +496,11 @@ bool HandlePowerctlMessage(const std::string& command) {
                                << err;
                 }
             }
-            // If there is an additional bootloader parameter, pass it along
-            if (cmd_params.size() == 3) {
+            // If there is an additional parameter, pass it along
+            if ((cmd_params.size() == 3) && cmd_params[2].size()) {
                 reboot_target += "," + cmd_params[2];
             }
         }
-    } else if (command == "thermal-shutdown") {  // no additional parameter allowed
-        // run_fsck is false to avoid delay
-        cmd = ANDROID_RB_THERMOFF;
     } else {
         command_invalid = true;
     }

init/reboot.h

@@ -27,7 +27,7 @@ void __attribute__((noreturn)) RebootSystem(unsigned int cmd, const std::string&
 
 /* Reboot / shutdown the system.
  * cmd ANDROID_RB_* as defined in android_reboot.h
- * reason Reason string like "reboot", "userrequested"
+ * reason Reason string like "reboot", "shutdown,userrequested"
  * rebootTarget Reboot target string like "bootloader". Otherwise, it should be an
  *              empty string.
  * runFsck Whether to run fsck after umount is done.

libcutils/android_reboot.c

@@ -35,11 +35,11 @@ int android_reboot(int cmd, int flags __unused, const char* arg) {
             restart_cmd = "shutdown";
             break;
         case ANDROID_RB_THERMOFF:
-            restart_cmd = "thermal-shutdown";
+            restart_cmd = "shutdown,thermal";
             break;
     }
     if (!restart_cmd) return -1;
-    if (arg) {
+    if (arg && arg[0]) {
         ret = asprintf(&prop_value, "%s,%s", restart_cmd, arg);
     } else {
         ret = asprintf(&prop_value, "%s", restart_cmd);

libcutils/include/cutils/android_reboot.h

@@ -29,8 +29,8 @@ __BEGIN_DECLS
 /* Properties */
 #define ANDROID_RB_PROPERTY "sys.powerctl"
 
-/* Android reboot reason stored in this file */
-#define LAST_REBOOT_REASON_FILE "/data/misc/reboot/last_reboot_reason"
+/* Android reboot reason stored in this property */
+#define LAST_REBOOT_REASON_PROPERTY "persist.sys.boot.reason"
 
 /* Reboot or shutdown the system.
  * This call uses ANDROID_RB_PROPERTY to request reboot to init process.

rootdir/init.rc

@@ -430,7 +430,6 @@ on post-fs-data
     mkdir /data/misc/boottrace 0771 system shell
     mkdir /data/misc/update_engine 0700 root root
     mkdir /data/misc/trace 0700 root root
-    mkdir /data/misc/reboot 0700 system system
     # profile file layout
     mkdir /data/misc/profiles 0771 system system
     mkdir /data/misc/profiles/cur 0771 system system