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lavc/ffjni: remove use of private JniInvocation API to retreive the Java VM

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Android N will prevent users from loading non-public APIs.

Users should only rely on the av_jni_set_java_vm function to set the
Java VM.
This commit is contained in:
Matthieu Bouron 2016-03-11 20:59:40 +01:00
parent 370cecc1e8
commit 33d69a9008
1 changed files with 3 additions and 86 deletions
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89
libavcodec/ffjni.c
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@ -20,7 +20,6 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <dlfcn.h>
#include <jni.h>
#include <pthread.h>
#include <stdlib.h>
@ -35,80 +34,6 @@
static JavaVM *java_vm = NULL;
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
/**
* Check if JniInvocation has been initialized. Only available on
* Android >= 4.4.
*
* @param log_ctx context used for logging, can be NULL
* @return 0 on success, < 0 otherwise
*/
static int check_jni_invocation(void *log_ctx)
{
int ret = AVERROR_EXTERNAL;
void *handle = NULL;
void **jni_invocation = NULL;
handle = dlopen(NULL, RTLD_LOCAL);
if (!handle) {
goto done;
}
jni_invocation = (void **)dlsym(handle, "_ZN13JniInvocation15jni_invocation_E");
if (!jni_invocation) {
av_log(log_ctx, AV_LOG_ERROR, "Could not find JniInvocation::jni_invocation_ symbol\n");
goto done;
}
ret = !(jni_invocation != NULL && *jni_invocation != NULL);
done:
if (handle) {
dlclose(handle);
}
return ret;
}
/**
* Return created Java virtual machine using private JNI_GetCreatedJavaVMs
* function from the specified library name.
*
* @param name library name used for symbol lookups, can be NULL
* @param log_ctx context used for logging, can be NULL
* @return the current Java virtual machine in use
*/
static JavaVM *get_java_vm(const char *name, void *log_ctx)
{
JavaVM *vm = NULL;
jsize nb_vm = 0;
void *handle = NULL;
jint (*get_created_java_vms) (JavaVM ** vmBuf, jsize bufLen, jsize *nVMs) = NULL;
handle = dlopen(name, RTLD_LOCAL);
if (!handle) {
return NULL;
}
get_created_java_vms = (jint (*)(JavaVM **, jsize, jsize *)) dlsym(handle, "JNI_GetCreatedJavaVMs");
if (!get_created_java_vms) {
av_log(log_ctx, AV_LOG_ERROR, "Could not find JNI_GetCreatedJavaVMs symbol in library '%s'\n", name);
goto done;
}
if (get_created_java_vms(&vm, 1, &nb_vm) != JNI_OK) {
av_log(log_ctx, AV_LOG_ERROR, "Could not get created Java virtual machines\n");
goto done;
}
done:
if (handle) {
dlclose(handle);
}
return vm;
}
JNIEnv *ff_jni_attach_env(int *attached, void *log_ctx)
{
int ret = 0;
@ -117,21 +42,13 @@ JNIEnv *ff_jni_attach_env(int *attached, void *log_ctx)
*attached = 0;
pthread_mutex_lock(&lock);
if (java_vm == NULL && (java_vm = av_jni_get_java_vm(log_ctx)) == NULL) {
av_log(log_ctx, AV_LOG_INFO, "Retrieving current Java virtual machine using Android JniInvocation wrapper\n");
if (check_jni_invocation(log_ctx) == 0) {
if ((java_vm = get_java_vm(NULL, log_ctx)) != NULL ||
(java_vm = get_java_vm("libdvm.so", log_ctx)) != NULL ||
(java_vm = get_java_vm("libart.so", log_ctx)) != NULL) {
av_log(log_ctx, AV_LOG_INFO, "Found Java virtual machine using Android JniInvocation wrapper\n");
}
}
if (java_vm == NULL) {
java_vm = av_jni_get_java_vm(log_ctx);
}
pthread_mutex_unlock(&lock);
if (!java_vm) {
av_log(log_ctx, AV_LOG_ERROR, "Could not retrieve a Java virtual machine\n");
av_log(log_ctx, AV_LOG_ERROR, "No Java virtual machine has been registered\n");
return NULL;
}