From d96c6b8e881054de1eb38ac87612b975ec4aaf27 Mon Sep 17 00:00:00 2001
From: terryguan <terryguan@google.com>
Date: Fri, 16 Aug 2024 14:27:23 -0700
Subject: [PATCH] Add resume from hibernation in first stage init

If bootconfig hibernation_resume_device is present in boot config, then
we write that value to /sys/power/resume

Bug: 339688542
Test: Check resume from hibernation/boots with/without config present
Change-Id: I1a9bf63af4dab07e494740722898c1aba33c00b5
---
 fs_mgr/libfstab/fstab_priv.h          |  3 ---
 fs_mgr/libfstab/include/fstab/fstab.h |  3 +++
 init/first_stage_init.cpp             | 19 +++++++++++++++++++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/fs_mgr/libfstab/fstab_priv.h b/fs_mgr/libfstab/fstab_priv.h
index 5105da001..73cb17518 100644
--- a/fs_mgr/libfstab/fstab_priv.h
+++ b/fs_mgr/libfstab/fstab_priv.h
@@ -39,9 +39,6 @@ std::string GetFstabPath();
 void ImportBootconfigFromString(const std::string& bootconfig,
                                 const std::function<void(std::string, std::string)>& fn);
 
-bool GetBootconfigFromString(const std::string& bootconfig, const std::string& key,
-                             std::string* out);
-
 void ImportKernelCmdlineFromString(const std::string& cmdline,
                                    const std::function<void(std::string, std::string)>& fn);
 
diff --git a/fs_mgr/libfstab/include/fstab/fstab.h b/fs_mgr/libfstab/include/fstab/fstab.h
index 1696daff0..21fe01726 100644
--- a/fs_mgr/libfstab/include/fstab/fstab.h
+++ b/fs_mgr/libfstab/include/fstab/fstab.h
@@ -153,5 +153,8 @@ bool GetKernelCmdline(const std::string& key, std::string* out);
 // Return the "other" slot for the given slot suffix.
 std::string OtherSlotSuffix(const std::string& suffix);
 
+bool GetBootconfigFromString(const std::string& bootconfig, const std::string& key,
+                             std::string* out);
+
 }  // namespace fs_mgr
 }  // namespace android
diff --git a/init/first_stage_init.cpp b/init/first_stage_init.cpp
index bfe636bbf..e06a64593 100644
--- a/init/first_stage_init.cpp
+++ b/init/first_stage_init.cpp
@@ -38,6 +38,7 @@
 #include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 #include <android/avf_cc_flags.h>
+#include <fs_mgr.h>
 #include <modprobe/modprobe.h>
 #include <private/android_filesystem_config.h>
 
@@ -303,6 +304,22 @@ static BootMode GetBootMode(const std::string& cmdline, const std::string& bootc
     return BootMode::NORMAL_MODE;
 }
 
+static void MaybeResumeFromHibernation(const std::string& bootconfig) {
+    std::string hibernationResumeDevice;
+    android::fs_mgr::GetBootconfigFromString(bootconfig, "androidboot.hibernation_resume_device",
+                                             &hibernationResumeDevice);
+    if (!hibernationResumeDevice.empty()) {
+        android::base::unique_fd fd(open("/sys/power/resume", O_RDWR | O_CLOEXEC));
+        if (fd >= 0) {
+            if (!android::base::WriteStringToFd(hibernationResumeDevice, fd)) {
+                PLOG(ERROR) << "Failed to write to /sys/power/resume";
+            }
+        } else {
+            PLOG(ERROR) << "Failed to open /sys/power/resume";
+        }
+    }
+}
+
 static std::unique_ptr<FirstStageMount> CreateFirstStageMount(const std::string& cmdline) {
     auto ret = FirstStageMount::Create(cmdline);
     if (ret.ok()) {
@@ -442,6 +459,8 @@ int FirstStageMain(int argc, char** argv) {
                   << module_elapse_time.count() << " ms";
     }
 
+    MaybeResumeFromHibernation(bootconfig);
+
     std::unique_ptr<FirstStageMount> fsm;
 
     bool created_devices = false;