diff --git a/media/libdatasource/FileSource.cpp b/media/libdatasource/FileSource.cpp
index 65780e3..bbf7dda 100644
--- a/media/libdatasource/FileSource.cpp
+++ b/media/libdatasource/FileSource.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009 The Android Open Source Project
+ * 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.
@@ -20,45 +20,84 @@
 
 #include <datasource/FileSource.h>
 #include <media/stagefright/foundation/ADebug.h>
-#include <private/android_filesystem_config.h>
+#include <media/stagefright/FoundationUtils.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 
 namespace android {
 
 FileSource::FileSource(const char *filename)
-    : ClearFileSource(filename),
-      mDecryptHandle(NULL),
-      mDrmManagerClient(NULL),
-      mDrmBufOffset(0),
-      mDrmBufSize(0),
-      mDrmBuf(NULL){
+    : mFd(-1),
+      mOffset(0),
+      mLength(-1),
+      mName("<null>") {
+
+    if (filename) {
+        mName = String8::format("FileSource(%s)", filename);
+    }
+    ALOGV("%s", filename);
+    mFd = open(filename, O_LARGEFILE | O_RDONLY);
+
+    if (mFd >= 0) {
+        mLength = lseek64(mFd, 0, SEEK_END);
+    } else {
+        ALOGE("Failed to open file '%s'. (%s)", filename, strerror(errno));
+    }
 }
 
 FileSource::FileSource(int fd, int64_t offset, int64_t length)
-    : ClearFileSource(fd, offset, length),
-      mDecryptHandle(NULL),
-      mDrmManagerClient(NULL),
-      mDrmBufOffset(0),
-      mDrmBufSize(0),
-      mDrmBuf(NULL) {
+    : mFd(fd),
+      mOffset(offset),
+      mLength(length),
+      mName("<null>") {
+    ALOGV("fd=%d (%s), offset=%lld, length=%lld",
+            fd, nameForFd(fd).c_str(), (long long) offset, (long long) length);
+
+    if (mOffset < 0) {
+        mOffset = 0;
+    }
+    if (mLength < 0) {
+        mLength = 0;
+    }
+    if (mLength > INT64_MAX - mOffset) {
+        mLength = INT64_MAX - mOffset;
+    }
+    struct stat s;
+    if (fstat(fd, &s) == 0) {
+        if (mOffset > s.st_size) {
+            mOffset = s.st_size;
+            mLength = 0;
+        }
+        if (mOffset + mLength > s.st_size) {
+            mLength = s.st_size - mOffset;
+        }
+    }
+    if (mOffset != offset || mLength != length) {
+        ALOGW("offset/length adjusted from %lld/%lld to %lld/%lld",
+                (long long) offset, (long long) length,
+                (long long) mOffset, (long long) mLength);
+    }
+
+    mName = String8::format(
+            "FileSource(fd(%s), %lld, %lld)",
+            nameForFd(fd).c_str(),
+            (long long) mOffset,
+            (long long) mLength);
+
 }
 
 FileSource::~FileSource() {
-    if (mDrmBuf != NULL) {
-        delete[] mDrmBuf;
-        mDrmBuf = NULL;
+    if (mFd >= 0) {
+        ::close(mFd);
+        mFd = -1;
     }
+}
 
-    if (mDecryptHandle != NULL) {
-        // To release mDecryptHandle
-        CHECK(mDrmManagerClient);
-        mDrmManagerClient->closeDecryptSession(mDecryptHandle);
-        mDecryptHandle = NULL;
-    }
-
-    if (mDrmManagerClient != NULL) {
-        delete mDrmManagerClient;
-        mDrmManagerClient = NULL;
-    }
+status_t FileSource::initCheck() const {
+    return mFd >= 0 ? OK : NO_INIT;
 }
 
 ssize_t FileSource::readAt(off64_t offset, void *data, size_t size) {
@@ -67,7 +106,6 @@
     }
 
     Mutex::Autolock autoLock(mLock);
-
     if (mLength >= 0) {
         if (offset >= mLength) {
             return 0;  // read beyond EOF.
@@ -77,79 +115,29 @@
             size = numAvailable;
         }
     }
-
-    if (mDecryptHandle != NULL && DecryptApiType::CONTAINER_BASED
-            == mDecryptHandle->decryptApiType) {
-        return readAtDRM_l(offset, data, size);
-   } else {
-        return readAt_l(offset, data, size);
-    }
+    return readAt_l(offset, data, size);
 }
 
-sp<DecryptHandle> FileSource::DrmInitialization(const char *mime) {
-    if (getuid() == AID_MEDIA_EX) return nullptr; // no DRM in media extractor
-    if (mDrmManagerClient == NULL) {
-        mDrmManagerClient = new DrmManagerClient();
+ssize_t FileSource::readAt_l(off64_t offset, void *data, size_t size) {
+    off64_t result = lseek64(mFd, offset + mOffset, SEEK_SET);
+    if (result == -1) {
+        ALOGE("seek to %lld failed", (long long)(offset + mOffset));
+        return UNKNOWN_ERROR;
     }
 
-    if (mDrmManagerClient == NULL) {
-        return NULL;
-    }
-
-    if (mDecryptHandle == NULL) {
-        mDecryptHandle = mDrmManagerClient->openDecryptSession(
-                mFd, mOffset, mLength, mime);
-    }
-
-    if (mDecryptHandle == NULL) {
-        delete mDrmManagerClient;
-        mDrmManagerClient = NULL;
-    }
-
-    return mDecryptHandle;
+    return ::read(mFd, data, size);
 }
 
-ssize_t FileSource::readAtDRM_l(off64_t offset, void *data, size_t size) {
-    size_t DRM_CACHE_SIZE = 1024;
-    if (mDrmBuf == NULL) {
-        mDrmBuf = new unsigned char[DRM_CACHE_SIZE];
+status_t FileSource::getSize(off64_t *size) {
+    Mutex::Autolock autoLock(mLock);
+
+    if (mFd < 0) {
+        return NO_INIT;
     }
 
-    if (mDrmBuf != NULL && mDrmBufSize > 0 && (offset + mOffset) >= mDrmBufOffset
-            && (offset + mOffset + size) <= static_cast<size_t>(mDrmBufOffset + mDrmBufSize)) {
-        /* Use buffered data */
-        memcpy(data, (void*)(mDrmBuf+(offset+mOffset-mDrmBufOffset)), size);
-        return size;
-    } else if (size <= DRM_CACHE_SIZE) {
-        /* Buffer new data */
-        mDrmBufOffset =  offset + mOffset;
-        mDrmBufSize = mDrmManagerClient->pread(mDecryptHandle, mDrmBuf,
-                DRM_CACHE_SIZE, offset + mOffset);
-        if (mDrmBufSize > 0) {
-            int64_t dataRead = 0;
-            dataRead = size > static_cast<size_t>(mDrmBufSize) ? mDrmBufSize : size;
-            memcpy(data, (void*)mDrmBuf, dataRead);
-            return dataRead;
-        } else {
-            return mDrmBufSize;
-        }
-    } else {
-        /* Too big chunk to cache. Call DRM directly */
-        return mDrmManagerClient->pread(mDecryptHandle, data, size, offset + mOffset);
-    }
-}
+    *size = mLength;
 
-/* static */
-bool FileSource::requiresDrm(int fd, int64_t offset, int64_t length, const char *mime) {
-    std::unique_ptr<DrmManagerClient> drmClient(new DrmManagerClient());
-    sp<DecryptHandle> decryptHandle =
-            drmClient->openDecryptSession(fd, offset, length, mime);
-    bool requiresDrm = false;
-    if (decryptHandle != nullptr) {
-        requiresDrm = decryptHandle->decryptApiType == DecryptApiType::CONTAINER_BASED;
-        drmClient->closeDecryptSession(decryptHandle);
-    }
-    return requiresDrm;
+    return OK;
 }
 
 }  // namespace android