Load crypto plugins from additional shared libraries

Currently crypto plugins are expected to be in libdrmdecrypt.so.
When there are multiple plugins supporting different schemes,
this approach requires source code integration across
vendors which is unmanagable.  Also, for integration with
MediaDrm where the crypto keys are obtained from a drm server,
the MediaCrypto plugin needs to interoperate with the MediaDrm
plugin. This change allows {MediaCrypto, MediaDrm} pairs that
are logically related to be implemented in a common shared
library.

Change-Id: I7f6638f29171f91609fc2d944396365568630b56

1 files changed, 126 insertions, 35 deletions

diff --git a/media/libmediaplayerservice/Crypto.cpp b/media/libmediaplayerservice/Crypto.cpp
index 0e8f913..ae4d845 100644
--- a/media/libmediaplayerservice/Crypto.cpp
+++ b/media/libmediaplayerservice/Crypto.cpp
@@ -17,6 +17,8 @@
 //#define LOG_NDEBUG 0
 #define LOG_TAG "Crypto"
 #include <utils/Log.h>
+#include <dirent.h>
+#include <dlfcn.h>
 
 #include "Crypto.h"
 
@@ -26,87 +28,176 @@
 #include <media/stagefright/foundation/hexdump.h>
 #include <media/stagefright/MediaErrors.h>
 
-#include <dlfcn.h>
-
 namespace android {
 
+KeyedVector<Vector<uint8_t>, String8> Crypto::mUUIDToLibraryPathMap;
+KeyedVector<String8, wp<SharedLibrary> > Crypto::mLibraryPathToOpenLibraryMap;
+Mutex Crypto::mMapLock;
+
+static bool operator<(const Vector<uint8_t> &lhs, const Vector<uint8_t> &rhs) {
+    if (lhs.size() < rhs.size()) {
+        return true;
+    } else if (lhs.size() > rhs.size()) {
+        return false;
+    }
+
+    return memcmp((void *)lhs.array(), (void *)rhs.array(), rhs.size()) < 0;
+}
+
 Crypto::Crypto()
     : mInitCheck(NO_INIT),
-      mLibHandle(NULL),
       mFactory(NULL),
       mPlugin(NULL) {
-    mInitCheck = init();
 }
 
 Crypto::~Crypto() {
     delete mPlugin;
     mPlugin = NULL;
+    closeFactory();
+}
 
+void Crypto::closeFactory() {
     delete mFactory;
     mFactory = NULL;
-
-    if (mLibHandle != NULL) {
-        dlclose(mLibHandle);
-        mLibHandle = NULL;
-    }
+    mLibrary.clear();
 }
 
 status_t Crypto::initCheck() const {
     return mInitCheck;
 }
 
-status_t Crypto::init() {
-    mLibHandle = dlopen("libdrmdecrypt.so", RTLD_NOW);
+/*
+ * Search the plugins directory for a plugin that supports the scheme
+ * specified by uuid
+ *
+ * If found:
+ *    mLibrary holds a strong pointer to the dlopen'd library
+ *    mFactory is set to the library's factory method
+ *    mInitCheck is set to OK
+ *
+ * If not found:
+ *    mLibrary is cleared and mFactory are set to NULL
+ *    mInitCheck is set to an error (!OK)
+ */
+void Crypto::findFactoryForScheme(const uint8_t uuid[16]) {
 
-    if (mLibHandle == NULL) {
-        ALOGE("Unable to locate libdrmdecrypt.so");
+    closeFactory();
 
-        return ERROR_UNSUPPORTED;
+    // lock static maps
+    Mutex::Autolock autoLock(mMapLock);
+
+    // first check cache
+    Vector<uint8_t> uuidVector;
+    uuidVector.appendArray(uuid, sizeof(uuid));
+    ssize_t index = mUUIDToLibraryPathMap.indexOfKey(uuidVector);
+    if (index >= 0) {
+        if (loadLibraryForScheme(mUUIDToLibraryPathMap[index], uuid)) {
+            mInitCheck = OK;
+            return;
+        } else {
+            ALOGE("Failed to load from cached library path!");
+            mInitCheck = ERROR_UNSUPPORTED;
+            return;
+        }
     }
 
-    typedef CryptoFactory *(*CreateCryptoFactoryFunc)();
-    CreateCryptoFactoryFunc createCryptoFactory =
-        (CreateCryptoFactoryFunc)dlsym(mLibHandle, "createCryptoFactory");
+    // no luck, have to search
+    String8 dirPath("/vendor/lib/mediadrm");
+    String8 pluginPath;
 
-    if (createCryptoFactory == NULL
-            || ((mFactory = createCryptoFactory()) == NULL)) {
-        if (createCryptoFactory == NULL) {
-            ALOGE("Unable to find symbol 'createCryptoFactory'.");
-        } else {
-            ALOGE("createCryptoFactory() failed.");
+    DIR* pDir = opendir(dirPath.string());
+    if (pDir) {
+        struct dirent* pEntry;
+        while ((pEntry = readdir(pDir))) {
+
+            pluginPath = dirPath + "/" + pEntry->d_name;
+
+            if (pluginPath.getPathExtension() == ".so") {
+
+                if (loadLibraryForScheme(pluginPath, uuid)) {
+                    mUUIDToLibraryPathMap.add(uuidVector, pluginPath);
+                    mInitCheck = OK;
+                    closedir(pDir);
+                    return;
+                }
+            }
         }
 
-        dlclose(mLibHandle);
-        mLibHandle = NULL;
+        closedir(pDir);
+    }
 
-        return ERROR_UNSUPPORTED;
+    // try the legacy libdrmdecrypt.so
+    pluginPath = "libdrmdecrypt.so";
+    if (loadLibraryForScheme(pluginPath, uuid)) {
+        mUUIDToLibraryPathMap.add(uuidVector, pluginPath);
+        mInitCheck = OK;
+        return;
     }
 
-    return OK;
+    ALOGE("Failed to find crypto plugin");
+    mInitCheck = ERROR_UNSUPPORTED;
 }
 
-bool Crypto::isCryptoSchemeSupported(const uint8_t uuid[16]) const {
-    Mutex::Autolock autoLock(mLock);
+bool Crypto::loadLibraryForScheme(const String8 &path, const uint8_t uuid[16]) {
 
-    if (mInitCheck != OK) {
+    // get strong pointer to open shared library
+    ssize_t index = mLibraryPathToOpenLibraryMap.indexOfKey(path);
+    if (index >= 0) {
+        mLibrary = mLibraryPathToOpenLibraryMap[index].promote();
+    } else {
+        index = mLibraryPathToOpenLibraryMap.add(path, NULL);
+    }
+
+    if (!mLibrary.get()) {
+        mLibrary = new SharedLibrary(path);
+        if (!*mLibrary) {
+            return false;
+        }
+
+        mLibraryPathToOpenLibraryMap.replaceValueAt(index, mLibrary);
+    }
+
+    typedef CryptoFactory *(*CreateCryptoFactoryFunc)();
+
+    CreateCryptoFactoryFunc createCryptoFactory =
+        (CreateCryptoFactoryFunc)mLibrary->lookup("createCryptoFactory");
+
+    if (createCryptoFactory == NULL ||
+        (mFactory = createCryptoFactory()) == NULL ||
+        !mFactory->isCryptoSchemeSupported(uuid)) {
+        closeFactory();
         return false;
     }
+    return true;
+}
 
-    return mFactory->isCryptoSchemeSupported(uuid);
+bool Crypto::isCryptoSchemeSupported(const uint8_t uuid[16]) {
+    Mutex::Autolock autoLock(mLock);
+
+    if (mFactory && mFactory->isCryptoSchemeSupported(uuid)) {
+        return true;
+    }
+
+    findFactoryForScheme(uuid);
+    return (mInitCheck == OK);
 }
 
 status_t Crypto::createPlugin(
         const uint8_t uuid[16], const void *data, size_t size) {
     Mutex::Autolock autoLock(mLock);
 
-    if (mInitCheck != OK) {
-        return mInitCheck;
-    }
-
     if (mPlugin != NULL) {
         return -EINVAL;
     }
 
+    if (!mFactory || !mFactory->isCryptoSchemeSupported(uuid)) {
+        findFactoryForScheme(uuid);
+    }
+
+    if (mInitCheck != OK) {
+        return mInitCheck;
+    }
+
     return mFactory->createPlugin(uuid, data, size, &mPlugin);
 }