/**
* getJNIEnv: A helper function to get the JNIEnv* for the given thread.
* If no JVM exists, then one will be created. JVM command line arguments
* are obtained from the LIBHDFS_OPTS environment variable.
*
* @param: None.
* @return The JNIEnv* corresponding to the thread.
*/
JNIEnv* getJNIEnv(void)
{
const jsize vmBufLength = 1;
JavaVM* vmBuf[vmBufLength];
JNIEnv *env;
jint rv = 0;
jint noVMs = 0;
// Only the first thread should create the JVM. The other trheads should
// just use the JVM created by the first thread.
LOCK_JVM_MUTEX();
rv = JNI_GetCreatedJavaVMs(&(vmBuf[0]), vmBufLength, &noVMs);
if (rv != 0) {
fprintf(stderr, "JNI_GetCreatedJavaVMs failed with error: %d\n", rv);
UNLOCK_JVM_MUTEX();
return NULL;
}
if (noVMs == 0) {
//Get the environment variables for initializing the JVM
char *hadoopClassPath = getenv("CLASSPATH");
if (hadoopClassPath == NULL) {
fprintf(stderr, "Environment variable CLASSPATH not set!\n");
UNLOCK_JVM_MUTEX();
return NULL;
}
char *hadoopClassPathVMArg = "-Djava.class.path=";
size_t optHadoopClassPathLen = strlen(hadoopClassPath) +
strlen(hadoopClassPathVMArg) + 1;
char *optHadoopClassPath = malloc(sizeof(char)*optHadoopClassPathLen);
snprintf(optHadoopClassPath, optHadoopClassPathLen,
"%s%s", hadoopClassPathVMArg, hadoopClassPath);
int noArgs = 1;
//determine how many arguments were passed as LIBHDFS_OPTS env var
char *hadoopJvmArgs = getenv("LIBHDFS_OPTS");
char jvmArgDelims[] = " ";
if (hadoopJvmArgs != NULL) {
char *result = NULL;
result = strtok( hadoopJvmArgs, jvmArgDelims );
while ( result != NULL ) {
noArgs++;
result = strtok( NULL, jvmArgDelims);
}
}
JavaVMOption options[noArgs];
options[0].optionString = optHadoopClassPath;
//fill in any specified arguments
if (hadoopJvmArgs != NULL) {
char *result = NULL;
result = strtok( hadoopJvmArgs, jvmArgDelims );
int argNum = 1;
for (;argNum < noArgs ; argNum++) {
options[argNum].optionString = result; //optHadoopArg;
}
}
//Create the VM
JavaVMInitArgs vm_args;
JavaVM *vm;
vm_args.version = JNI_VERSION_1_2;
vm_args.options = options;
vm_args.nOptions = noArgs;
vm_args.ignoreUnrecognized = 1;
rv = JNI_CreateJavaVM(&vm, (void*)&env, &vm_args);
if (rv != 0) {
fprintf(stderr, "Call to JNI_CreateJavaVM failed "
"with error: %d\n", rv);
UNLOCK_JVM_MUTEX();
return NULL;
}
free(optHadoopClassPath);
}
else {
//Attach this thread to the VM
JavaVM* vm = vmBuf[0];
rv = (*vm)->AttachCurrentThread(vm, (void*)&env, 0);
if (rv != 0) {
fprintf(stderr, "Call to AttachCurrentThread "
"failed with error: %d\n", rv);
UNLOCK_JVM_MUTEX();
return NULL;
}
}
UNLOCK_JVM_MUTEX();
return env;
}
/**
* getJNIEnv: A helper function to get the JNIEnv* for the given thread.
* If no JVM exists, then one will be created. JVM command line arguments
* are obtained from the LIBHDFS_OPTS environment variable.
*
* @param: None.
* @return The JNIEnv* corresponding to the thread.
*/
JNIEnv* getJNIEnv(void)
{
const jsize vmBufLength = 1;
JavaVM* vmBuf[vmBufLength];
JNIEnv *env;
jint rv = 0;
jint noVMs = 0;
// Only the first thread should create the JVM. The other trheads should
// just use the JVM created by the first thread.
LOCK_JVM_MUTEX();
rv = JNI_GetCreatedJavaVMs(&(vmBuf[0]), vmBufLength, &noVMs);
if (rv != 0) {
fprintf(stderr, "JNI_GetCreatedJavaVMs failed with error: %d\n", rv);
UNLOCK_JVM_MUTEX();
return NULL;
}
if (noVMs == 0) {
//Get the environment variables for initializing the JVM
char *hadoopClassPath = getenv("CLASSPATH");
if (hadoopClassPath == NULL) {
fprintf(stderr, "Environment variable CLASSPATH not set!\n");
UNLOCK_JVM_MUTEX();
return NULL;
}
char *hadoopClassPathVMArg = "-Djava.class.path=";
size_t optHadoopClassPathLen = strlen(hadoopClassPath) +
strlen(hadoopClassPathVMArg) + 1;
char *optHadoopClassPath = malloc(sizeof(char)*optHadoopClassPathLen);
snprintf(optHadoopClassPath, optHadoopClassPathLen,
"%s%s", hadoopClassPathVMArg, hadoopClassPath);
// Determine the # of LIBHDFS_OPTS args
int noArgs = 1;
char *hadoopJvmArgs = getenv("LIBHDFS_OPTS");
char jvmArgDelims[] = " ";
char *str, *token, *savePtr;
if (hadoopJvmArgs != NULL) {
hadoopJvmArgs = strdup(hadoopJvmArgs);
for (noArgs = 1, str = hadoopJvmArgs; ; noArgs++, str = NULL) {
token = strtok_r(str, jvmArgDelims, &savePtr);
if (NULL == token) {
break;
}
}
free(hadoopJvmArgs);
}
// Now that we know the # args, populate the options array
JavaVMOption options[noArgs];
options[0].optionString = optHadoopClassPath;
hadoopJvmArgs = getenv("LIBHDFS_OPTS");
if (hadoopJvmArgs != NULL) {
hadoopJvmArgs = strdup(hadoopJvmArgs);
for (noArgs = 1, str = hadoopJvmArgs; ; noArgs++, str = NULL) {
token = strtok_r(str, jvmArgDelims, &savePtr);
if (NULL == token) {
break;
}
options[noArgs].optionString = token;
}
}
//Create the VM
JavaVMInitArgs vm_args;
JavaVM *vm;
vm_args.version = JNI_VERSION_1_2;
vm_args.options = options;
vm_args.nOptions = noArgs;
vm_args.ignoreUnrecognized = 1;
rv = JNI_CreateJavaVM(&vm, (void*)&env, &vm_args);
if (hadoopJvmArgs != NULL) {
free(hadoopJvmArgs);
}
free(optHadoopClassPath);
if (rv != 0) {
fprintf(stderr, "Call to JNI_CreateJavaVM failed "
"with error: %d\n", rv);
UNLOCK_JVM_MUTEX();
return NULL;
}
}
else {
//Attach this thread to the VM
JavaVM* vm = vmBuf[0];
rv = (*vm)->AttachCurrentThread(vm, (void*)&env, 0);
if (rv != 0) {
fprintf(stderr, "Call to AttachCurrentThread "
"failed with error: %d\n", rv);
UNLOCK_JVM_MUTEX();
return NULL;
}
}
UNLOCK_JVM_MUTEX();
return env;
}