From e0a9c90bf5ab1ba58b7435a602713227fb052e4a Mon Sep 17 00:00:00 2001
From: Tri Vo <trong@google.com>
Date: Tue, 28 Aug 2018 13:58:01 -0700
Subject: [PATCH] libpower: acquire wake locks from SystemSuspend service.

This change routes libpower and libhardware_legacy to SystemSuspend service for
wake locks instead of /sys/power/wake_[un]lock.

Bug: 78888165
Bug: 115946999
Test: /sys/kernel/debug/suspend_stats shows that device suspends if left alone
Change-Id: Id4d392e13d06be6d86e3112dedeb6a57bb24c06f
---
 Android.bp |  20 +++------
 power.c    | 124 -----------------------------------------------------
 power.cpp  |  72 +++++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 138 deletions(-)
 delete mode 100644 power.c
 create mode 100644 power.cpp

diff --git a/Android.bp b/Android.bp
index 066afcf..31fd49f 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,9 +1,5 @@
 // Copyright 2006 The Android Open Source Project
 
-subdirs = [
-    "audio",
-]
-
 cc_library_headers {
     name: "libhardware_legacy_headers",
     vendor_available: true,
@@ -15,11 +11,10 @@ cc_library_headers {
 
 cc_library {
     name: "libpower",
-
-    srcs: ["power.c"],
-    cflags: ["-Wall", "-Werror"],
+    defaults: ["system_suspend_defaults"],
+    srcs: ["power.cpp"],
     export_include_dirs: ["include"],
-    shared_libs: ["libcutils", "liblog"],
+    shared_libs: ["android.system.suspend@1.0"],
     vendor_available: true,
     vndk: {
         enabled: true,
@@ -28,16 +23,15 @@ cc_library {
 
 cc_library_shared {
     name: "libhardware_legacy",
+    defaults: ["system_suspend_defaults"],
     vendor_available: true,
     vndk: {
         enabled: true,
     },
 
     shared_libs: [
-        "libbase",
+        "android.system.suspend@1.0",
         "libdl",
-        "libcutils",
-        "liblog",
     ],
 
     header_libs: [
@@ -51,12 +45,10 @@ cc_library_shared {
         "-DQEMU_HARDWARE",
         "-Wall",
         "-Werror",
-        "-Wno-unused-parameter",
-        "-Wno-gnu-designator",
     ],
 
     srcs: [
-        "power.c",
+        "power.cpp",
         "uevent.c",
     ],
 }
diff --git a/power.c b/power.c
deleted file mode 100644
index fb60428..0000000
--- a/power.c
+++ /dev/null
@@ -1,124 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-#include <hardware_legacy/power.h>
-#include <fcntl.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <pthread.h>
-
-#define LOG_TAG "power"
-#include <log/log.h>
-
-enum {
-    ACQUIRE_PARTIAL_WAKE_LOCK = 0,
-    RELEASE_WAKE_LOCK,
-    OUR_FD_COUNT
-};
-
-const char * const OLD_PATHS[] = {
-    "/sys/android_power/acquire_partial_wake_lock",
-    "/sys/android_power/release_wake_lock",
-};
-
-const char * const NEW_PATHS[] = {
-    "/sys/power/wake_lock",
-    "/sys/power/wake_unlock",
-};
-
-//XXX static pthread_once_t g_initialized = THREAD_ONCE_INIT;
-static int g_initialized = 0;
-static int g_fds[OUR_FD_COUNT];
-static int g_error = -1;
-
-static int
-open_file_descriptors(const char * const paths[])
-{
-    int i;
-    for (i=0; i<OUR_FD_COUNT; i++) {
-        int fd = open(paths[i], O_RDWR | O_CLOEXEC);
-        if (fd < 0) {
-            g_error = -errno;
-            ALOGE("fatal error opening \"%s\": %s\n", paths[i],
-                strerror(errno));
-            return -1;
-        }
-        g_fds[i] = fd;
-    }
-
-    g_error = 0;
-    return 0;
-}
-
-static inline void
-initialize_fds(void)
-{
-    // XXX: should be this:
-    //pthread_once(&g_initialized, open_file_descriptors);
-    // XXX: not this:
-    if (g_initialized == 0) {
-        if(open_file_descriptors(NEW_PATHS) < 0)
-            open_file_descriptors(OLD_PATHS);
-        g_initialized = 1;
-    }
-}
-
-int
-acquire_wake_lock(int lock, const char* id)
-{
-    initialize_fds();
-
-//    ALOGI("acquire_wake_lock lock=%d id='%s'\n", lock, id);
-
-    if (g_error) return g_error;
-
-    int fd;
-    ssize_t ret;
-
-    if (lock != PARTIAL_WAKE_LOCK) {
-        return -EINVAL;
-    }
-
-    fd = g_fds[ACQUIRE_PARTIAL_WAKE_LOCK];
-
-    ret = write(fd, id, strlen(id));
-    if (ret < 0) {
-        return -errno;
-    }
-
-    return ret;
-}
-
-int
-release_wake_lock(const char* id)
-{
-    initialize_fds();
-
-//    ALOGI("release_wake_lock id='%s'\n", id);
-
-    if (g_error) return g_error;
-
-    ssize_t len = write(g_fds[RELEASE_WAKE_LOCK], id, strlen(id));
-    if (len < 0) {
-        return -errno;
-    }
-    return len;
-}
diff --git a/power.cpp b/power.cpp
new file mode 100644
index 0000000..8e07280
--- /dev/null
+++ b/power.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "power"
+#define ATRACE_TAG ATRACE_TAG_POWER
+
+#include <android-base/logging.h>
+#include <android/system/suspend/1.0/ISystemSuspend.h>
+#include <hardware_legacy/power.h>
+#include <utils/Trace.h>
+
+#include <mutex>
+#include <string>
+#include <thread>
+#include <unordered_map>
+
+using android::sp;
+using android::system::suspend::V1_0::ISystemSuspend;
+using android::system::suspend::V1_0::IWakeLock;
+using android::system::suspend::V1_0::WakeLockType;
+
+static std::mutex gLock;
+static std::unordered_map<std::string, sp<IWakeLock>> gWakeLockMap;
+
+static sp<ISystemSuspend> getSystemSuspendServiceOnce() {
+    static std::once_flag initFlag;
+    static sp<ISystemSuspend> suspendService = nullptr;
+    std::call_once(initFlag, []() {
+        // It's possible for the calling process to not have permissions to
+        // ISystemSuspend. getService will then return nullptr.
+        suspendService = ISystemSuspend::getService();
+    });
+    return suspendService;
+}
+
+int acquire_wake_lock(int, const char* id) {
+    ATRACE_CALL();
+    sp<ISystemSuspend> suspendService = getSystemSuspendServiceOnce();
+    if (!suspendService) {
+        return -1;
+    }
+
+    std::lock_guard<std::mutex> l{gLock};
+    if (!gWakeLockMap[id]) {
+        gWakeLockMap[id] = suspendService->acquireWakeLock(WakeLockType::PARTIAL, id);
+    }
+    return 0;
+}
+
+int release_wake_lock(const char* id) {
+    ATRACE_CALL();
+    std::lock_guard<std::mutex> l{gLock};
+    if (gWakeLockMap[id]) {
+        gWakeLockMap[id]->release();
+        gWakeLockMap[id] = nullptr;
+        return 0;
+    }
+    return -1;
+}