android tombstone

$ adb shell dumpsys dropbox --print 

라고 하면 tombstone 이 출력 됨.

출처 :https://stackoverflow.com/questions/28105054/default-tombstones-location-in-android

기본 위치는 여기. 재부팅 할때 dropbox 로 옮겨져.

/data/system/dropbox

dropbox 는 일정 용량 넘어가면 지워져.

Not to say this can't change in the future (and of course, being open source any vendor could modify this if they choose), but tombstone files are written by debuggerd in the engrave_tombstone()function implemented in tombstone.cpp (formerly tombstone.c):

• https://android.googlesource.com/platform/system/core/+/master/debuggerd/tombstone.cpp

This uses a hardcoded path using the macro:

#define TOMBSTONE_DIR "/data/tombstones"

Even the Java side of Android uses the hardcoded path:

• https://android.googlesource.com/platform/frameworks/base/+/master/core/java/com/android/server/BootReceiver.java

And it appears that using /data/tombstones goes at least back to Android 1.6 Donut's debuggerd

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출처 : https://developer.android.com/reference/android/os/DropBoxManager?authuser=0&hl=ro

Enqueues chunks of data (from various sources -- application crashes, kernel log records, etc.). The queue is size bounded and will drop old data if the enqueued data exceeds the maximum size. You can think of this as a persistent, system-wide, blob-oriented "logcat".

DropBoxManager entries are not sent anywhere directly, but other system services and debugging tools may scan and upload entries for processing.

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출처 : https://android.googlesource.com/platform/frameworks/base/+/android-6.0.1_r46/core/java/com/android/server/BootReceiver.java?fbclid=IwAR3p3j_bca4utCJB2XDDWjKlJuhkK_VilfH984lXXeYeAz0_xlhdD3CDBjw#153

// Scan existing tombstones (in case any new ones appeared)
	File[] tombstoneFiles = TOMBSTONE_DIR.listFiles();
	for (int i = 0; tombstoneFiles != null && i < tombstoneFiles.length; i++) {
	if (tombstoneFiles[i].isFile()) {
	addFileToDropBox(db, prefs, headers, tombstoneFiles[i].getPath(),
	LOG_SIZE, "SYSTEM_TOMBSTONE");
	}
	}

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출처 : 

/frameworks/base/core/java/android/provider/Settings.java

/**
         * Maximum number of entry files which {@link DropBoxManager} will keep
         * around.
         *
         * @hide
         */
        public static final String DROPBOX_MAX_FILES = "dropbox_max_files";

        /**
         * Maximum byte size of the low storage threshold. This is to ensure
         * that {@link #SYS_STORAGE_THRESHOLD_PERCENTAGE} does not result in an
         * overly large threshold for large storage devices. Currently this must
         * be less than 2GB. This default is 500MB.
         *
         * @hide
         */
        public static final String
                SYS_STORAGE_THRESHOLD_MAX_BYTES = "sys_storage_threshold_max_bytes";

7958        /**

7959         * Minimum percentage of free storage on the device that is used to

7960         * determine if the device is running low on storage. The default is 10.

7961         * <p>

7962         * Say this value is set to 10, the device is considered running low on

7963         * storage if 90% or more of the device storage is filled up.

7964         *

7965         * @hide

7966         */

7967        public static final String

7968                SYS_STORAGE_THRESHOLD_PERCENTAGE = "sys_storage_threshold_percentage";

/packages/apps/TV/usbtuner/src/com/android/usbtuner/exoplayer/cache/TrickplayStorageManager.java

    // Copied from android.os.StorageManager
    private static final int DEFAULT_THRESHOLD_PERCENTAGE = 10;
    private static final long DEFAULT_THRESHOLD_MAX_BYTES = 500L * 1024 * 1024;

/frameworks/base/services/core/java/com/android/server/DropBoxManagerService.java

/**
 * Implementation of {@link IDropBoxManagerService} using the filesystem.
 * Clients use {@link DropBoxManager} to access this service.
 */
public final class DropBoxManagerService extends SystemService {
    private static final String TAG = "DropBoxManagerService";
    private static final int DEFAULT_AGE_SECONDS = 3 * 86400;
    private static final int DEFAULT_MAX_FILES = 1000;
    private static final int DEFAULT_QUOTA_KB = 5 * 1024;
    private static final int DEFAULT_QUOTA_PERCENT = 10;
    private static final int DEFAULT_RESERVE_PERCENT = 10;
    private static final int QUOTA_RESCAN_MILLIS = 5000;

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