jlong DTraceJSDT::activate(
jint version, jstring module_name, jint providers_count,
JVM_DTraceProvider* providers, TRAPS) {
size_t count = 0;
RegisteredProbes* probes = NULL;
if (!is_supported()) {
return 0;
}
assert(module_name != NULL, "valid module name");
assert(providers != NULL, "valid provider array");
for (int i = 0; i < providers_count; ++i) {
count += providers[i].probe_count;
}
probes = new RegisteredProbes(count);
count = 0;
for (int i = 0; i < providers_count; ++i) {
assert(providers[i].name != NULL, "valid provider name");
assert(providers[i].probe_count == 0 || providers[i].probes != NULL,
"valid probe count");
for (int j = 0; j < providers[i].probe_count; ++j) {
JVM_DTraceProbe* probe = &(providers[i].probes[j]);
assert(probe != NULL, "valid probe");
assert(probe->method != NULL, "valid method");
assert(probe->name != NULL, "valid probe name");
assert(probe->function != NULL, "valid probe function spec");
methodHandle h_method =
methodHandle(THREAD, JNIHandles::resolve_jmethod_id(probe->method));
nmethod* nm = AdapterHandlerLibrary::create_dtrace_nmethod(h_method);
if (nm == NULL) {
delete probes;
THROW_MSG_0(vmSymbols::java_lang_RuntimeException(),
"Unable to register DTrace probes (CodeCache: no room for DTrace nmethods).");
}
h_method()->set_not_compilable(CompLevel_highest_tier);
h_method()->set_code(h_method, nm);
probes->nmethod_at_put(count++, nm);
}
}
int handle = pd_activate((void*)probes,
module_name, providers_count, providers);
if (handle <= 0) {
delete probes;
THROW_MSG_0(vmSymbols::java_lang_RuntimeException(),
"Unable to register DTrace probes (internal error).");
}
probes->set_helper_handle(handle);
return RegisteredProbes::toOpaqueProbes(probes);
}
// Unpacks one or more frames into user-supplied buffers.
// Updates the end index, and returns the number of unpacked frames.
// Always start with the existing vfst.method and bci.
// Do not call vfst.next to advance over the last returned value.
// In other words, do not leave any stale data in the vfst.
//
// Parameters:
// mode Restrict which frames to be decoded.
// BaseFrameStream stream of frames
// max_nframes Maximum number of frames to be filled.
// start_index Start index to the user-supplied buffers.
// frames_array Buffer to store Class or StackFrame in, starting at start_index.
// frames array is a Class<?>[] array when only getting caller
// reference, and a StackFrameInfo[] array (or derivative)
// otherwise. It should never be null.
// end_index End index to the user-supplied buffers with unpacked frames.
//
// Returns the number of frames whose information was transferred into the buffers.
//
int StackWalk::fill_in_frames(jlong mode, BaseFrameStream& stream,
int max_nframes, int start_index,
objArrayHandle frames_array,
int& end_index, TRAPS) {
log_debug(stackwalk)("fill_in_frames limit=%d start=%d frames length=%d",
max_nframes, start_index, frames_array->length());
assert(max_nframes > 0, "invalid max_nframes");
assert(start_index + max_nframes <= frames_array->length(), "oob");
int frames_decoded = 0;
for (; !stream.at_end(); stream.next()) {
Method* method = stream.method();
if (method == NULL) continue;
// skip hidden frames for default StackWalker option (i.e. SHOW_HIDDEN_FRAMES
// not set) and when StackWalker::getCallerClass is called
if (!ShowHiddenFrames && (skip_hidden_frames(mode) || get_caller_class(mode))) {
if (method->is_hidden()) {
if (log_is_enabled(Debug, stackwalk)) {
ResourceMark rm(THREAD);
outputStream* st = Log(stackwalk)::debug_stream();
st->print(" hidden method: ");
method->print_short_name(st);
st->cr();
}
continue;
}
}
int index = end_index++;
if (log_is_enabled(Debug, stackwalk)) {
ResourceMark rm(THREAD);
outputStream* st = Log(stackwalk)::debug_stream();
st->print(" %d: frame method: ", index);
method->print_short_name(st);
st->print_cr(" bci=%d", stream.bci());
}
if (!need_method_info(mode) && get_caller_class(mode) &&
index == start_index && method->caller_sensitive()) {
ResourceMark rm(THREAD);
THROW_MSG_0(vmSymbols::java_lang_UnsupportedOperationException(),
err_msg("StackWalker::getCallerClass called from @CallerSensitive %s method",
method->name_and_sig_as_C_string()));
}
// fill in StackFrameInfo and initialize MemberName
stream.fill_frame(index, frames_array, method, CHECK_0);
if (++frames_decoded >= max_nframes) break;
}
return frames_decoded;
}
address NativeLookup::lookup_base(methodHandle method, bool& in_base_library, TRAPS) {
address entry = NULL;
ResourceMark rm(THREAD);
entry = lookup_entry(method, in_base_library, THREAD);
if (entry != NULL) return entry;
// standard native method resolution has failed. Check if there are any
// JVM TI prefixes which have been applied to the native method name.
entry = lookup_entry_prefixed(method, in_base_library, THREAD);
if (entry != NULL) return entry;
// Native function not found, throw UnsatisfiedLinkError
THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
method->name_and_sig_as_C_string());
}
symbolOop symbolKlass::allocate_symbol(u1* name, int len, TRAPS) {
// Don't allow symbol oops to be created which cannot fit in a symbolOop.
if (len > symbolOopDesc::max_length()) {
THROW_MSG_0(vmSymbols::java_lang_InternalError(),
"name is too long to represent");
}
int size = symbolOopDesc::object_size(len);
symbolKlassHandle h_k(THREAD, as_klassOop());
symbolOop sym = (symbolOop)
CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_0);
assert(!sym->is_parsable(), "not expecting parsability yet.");
sym->set_next(NULL);
sym->set_utf8_length(len);
for (int i = 0; i < len; i++) {
sym->byte_at_put(i, name[i]);
}
// Let the first emptySymbol be created and
// ensure only one is ever created.
assert(sym->is_parsable() || Universe::emptySymbol() == NULL,
"should be parsable here.");
return sym;
}
// return the name of the user that owns the process identified by vmid.
//
// This method uses a slow directory search algorithm to find the backing
// store file for the specified vmid and returns the user name, as determined
// by the user name suffix of the hsperfdata_<username> directory name.
//
// the caller is expected to free the allocated memory.
//
static char* get_user_name_slow(int vmid, TRAPS) {
// short circuit the directory search if the process doesn't even exist.
if (kill(vmid, 0) == OS_ERR) {
if (errno == ESRCH) {
THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
"Process not found");
}
else /* EPERM */ {
THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno));
}
}
// directory search
char* oldest_user = NULL;
time_t oldest_ctime = 0;
const char* tmpdirname = os::get_temp_directory();
DIR* tmpdirp = os::opendir(tmpdirname);
if (tmpdirp == NULL) {
return NULL;
}
// for each entry in the directory that matches the pattern hsperfdata_*,
// open the directory and check if the file for the given vmid exists.
// The file with the expected name and the latest creation date is used
// to determine the user name for the process id.
//
struct dirent* dentry;
char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
errno = 0;
while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
// check if the directory entry is a hsperfdata file
if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
continue;
}
char* usrdir_name = NEW_C_HEAP_ARRAY(char,
strlen(tmpdirname) + strlen(dentry->d_name) + 2, mtInternal);
strcpy(usrdir_name, tmpdirname);
strcat(usrdir_name, "/");
strcat(usrdir_name, dentry->d_name);
// Open the user directory.
DIR* subdirp = open_directory_secure(usrdir_name);
if (subdirp == NULL) {
FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
continue;
}
// Since we don't create the backing store files in directories
// pointed to by symbolic links, we also don't follow them when
// looking for the files. We check for a symbolic link after the
// call to opendir in order to eliminate a small window where the
// symlink can be exploited.
//
if (!is_directory_secure(usrdir_name)) {
FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
os::closedir(subdirp);
continue;
}
struct dirent* udentry;
char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
errno = 0;
while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
if (filename_to_pid(udentry->d_name) == vmid) {
struct stat statbuf;
int result;
char* filename = NEW_C_HEAP_ARRAY(char,
strlen(usrdir_name) + strlen(udentry->d_name) + 2, mtInternal);
strcpy(filename, usrdir_name);
strcat(filename, "/");
strcat(filename, udentry->d_name);
// don't follow symbolic links for the file
RESTARTABLE(::lstat(filename, &statbuf), result);
if (result == OS_ERR) {
FREE_C_HEAP_ARRAY(char, filename, mtInternal);
continue;
}
// skip over files that are not regular files.
if (!S_ISREG(statbuf.st_mode)) {
FREE_C_HEAP_ARRAY(char, filename, mtInternal);
continue;
}
// compare and save filename with latest creation time
if (statbuf.st_size > 0 && statbuf.st_ctime > oldest_ctime) {
if (statbuf.st_ctime > oldest_ctime) {
char* user = strchr(dentry->d_name, '_') + 1;
if (oldest_user != NULL) FREE_C_HEAP_ARRAY(char, oldest_user, mtInternal);
oldest_user = NEW_C_HEAP_ARRAY(char, strlen(user)+1, mtInternal);
strcpy(oldest_user, user);
oldest_ctime = statbuf.st_ctime;
}
}
FREE_C_HEAP_ARRAY(char, filename, mtInternal);
}
}
os::closedir(subdirp);
FREE_C_HEAP_ARRAY(char, udbuf, mtInternal);
FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
}
