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Commit 6f451a9c authored by David Anderson's avatar David Anderson
Browse files

init: Issue a wipe on boot if trade-in mode was active. 

This modifies first-stage init to check for /metadata/tradeinmode/wipe
as soon as /metadata is mounted. If the file exists, we issue a request
to the bootloader to reboot to recovery and wipe /data. Since this also
wipes /metadata, the wipe indicator will be removed too.

In case some kind of failure happens in recovery, this also implements a
quick-and-dirty counter mechanism to fallback to the recovery menu.

Bug: 307713521
Test: touch /metadata/tradeinmode/wipe && adb reboot
Change-Id: I2d05903cadcdadf9c05f6736454db790a9e6b5bb
parent 47ec15c9

init/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -390,6 +390,7 @@ init_first_stage_cc_defaults { 
        "libsnapshot_init",

        "update_metadata-protos",

        "libprocinfo",

        "libbootloader_message",

    ],



    static_executable: true,

init/first_stage_mount.cpp

+57 −0
Original line number Diff line number Diff line
@@ -32,9 +32,12 @@ 
#include <android-base/chrono_utils.h>

#include <android-base/file.h>

#include <android-base/logging.h>

#include <android-base/parseint.h>

#include <android-base/stringprintf.h>

#include <android-base/strings.h>

#include <android/avf_cc_flags.h>

#include <bootloader_message/bootloader_message.h>

#include <cutils/android_reboot.h>

#include <fs_avb/fs_avb.h>

#include <fs_mgr.h>

#include <fs_mgr_dm_linear.h>
@@ -46,6 +49,7 @@ 


#include "block_dev_initializer.h"

#include "devices.h"

#include "reboot_utils.h"

#include "result.h"

#include "snapuserd_transition.h"

#include "switch_root.h"
@@ -111,6 +115,8 @@ class FirstStageMountVBootV2 : public FirstStageMount { 
    bool GetDmVerityDevices(std::set<std::string>* devices);

    bool SetUpDmVerity(FstabEntry* fstab_entry);



    void RequestTradeInModeWipeIfNeeded();



    bool InitAvbHandle();



    bool need_dm_verity_;
@@ -263,6 +269,8 @@ bool FirstStageMountVBootV2::DoCreateDevices() { 
}



bool FirstStageMountVBootV2::DoFirstStageMount() {

    RequestTradeInModeWipeIfNeeded();



    if (!IsDmLinearEnabled() && fstab_.empty()) {

        // Nothing to mount.

        LOG(INFO) << "First stage mount skipped (missing/incompatible/empty fstab in device tree)";
@@ -883,6 +891,55 @@ bool FirstStageMountVBootV2::InitAvbHandle() { 
    return true;

}



void FirstStageMountVBootV2::RequestTradeInModeWipeIfNeeded() {

    static constexpr const char* kWipeIndicator = "/metadata/tradeinmode/wipe";

    static constexpr size_t kWipeAttempts = 3;



    if (access(kWipeIndicator, R_OK) == -1) {

        return;

    }



    // Write a counter to the wipe indicator, to try and prevent boot loops if

    // recovery fails to wipe data.

    uint32_t counter = 0;

    std::string contents;

    if (ReadFileToString(kWipeIndicator, &contents)) {

        android::base::ParseUint(contents, &counter);

        contents = std::to_string(++counter);

        if (android::base::WriteStringToFile(contents, kWipeIndicator)) {

            sync();

        } else {

            PLOG(ERROR) << "Failed to update " << kWipeIndicator;

        }

    } else {

        PLOG(ERROR) << "Failed to read " << kWipeIndicator;

    }



    std::string err;

    auto misc_device = get_misc_blk_device(&err);

    if (misc_device.empty()) {

        LOG(FATAL) << "Could not find misc device: " << err;

    }



    auto misc_name = android::base::Basename(misc_device);

    if (!block_dev_init_.InitDevices({misc_name})) {

        LOG(FATAL) << "Could not find misc device: " << misc_device;

    }



    // If we've failed to wipe three times, don't include the wipe command. This

    // will force us to boot into the recovery menu instead where a manual wipe

    // can be attempted.

    std::vector<std::string> options;

    if (counter <= kWipeAttempts) {

        options.emplace_back("--wipe_data");

        options.emplace_back("--reason=tradeinmode");

    }

    if (!write_bootloader_message(options, &err)) {

        LOG(FATAL) << "Could not issue wipe: " << err;

    }

    RebootSystem(ANDROID_RB_RESTART2, "recovery", "reboot,tradeinmode,wipe");

}



void SetInitAvbVersionInRecovery() {

    if (!IsRecoveryMode()) {

        LOG(INFO) << "Skipped setting INIT_AVB_VERSION (not in recovery mode)";

rootdir/init.rc

+1 −0
Original line number Diff line number Diff line
@@ -644,6 +644,7 @@ on post-fs 
    mkdir /metadata/ota 0750 root system

    mkdir /metadata/ota/snapshots 0750 root system

    mkdir /metadata/watchdog 0770 root system

    mkdir /metadata/tradeinmode 0770 root system



    mkdir /metadata/apex 0700 root system

    mkdir /metadata/apex/sessions 0700 root system