DO NOT REVIEW: Update Java profiling agent to the latest version

Dockerfile

@@ -38,22 +38,31 @@ RUN apt-get update && apt-get -y -q install \
   curl \
   g++ \
   git \
-  libcurl4-openssl-dev \
-  libssl-dev \
   libtool \
   make \
   openjdk-11-jdk-headless \
   python \
   unzip \
   zlib1g-dev
 
+# openssl
+# This openssl (compiled with -fPIC) is used to statically link into the agent
+# shared library.
+ENV PKG_CONFIG_PATH=/usr/local/ssl/lib/pkgconfig
+RUN mkdir /tmp/openssl && cd /tmp/openssl && \
+    curl -sL https://github.com/openssl/openssl/archive/OpenSSL_1_1_1f.tar.gz | \
+        tar xzv --strip=1 && \
+    ./config no-shared -fPIC --openssldir=/usr/local/ssl --prefix=/usr/local/ssl && \
+    make && make install_sw && \
+    cd ~ && rm -rf /tmp/openssl
+
 # curl
-RUN git clone --depth=1 -b curl-7_55_1 https://github.com/curl/curl.git /tmp/curl && \
+RUN git clone --depth=1 -b curl-7_66_0 https://github.com/curl/curl.git /tmp/curl && \
     cd /tmp/curl && \
     ./buildconf && \
     ./configure --disable-ldap --disable-shared --without-libssh2 \
                 --without-librtmp --without-libidn --enable-static \
-                --with-pic --with-ssl && \
+                --with-pic --with-ssl=/usr/local/ssl/ && \
     make -j && make install && \
     cd ~ && rm -rf /tmp/curl
 
@@ -72,34 +81,19 @@ RUN mkdir /tmp/glog && cd /tmp/glog && \
     make -j && make install && \
     cd ~ && rm -rf /tmp/glog
 
-# openssl
-# This openssl (compiled with -fPIC) is used to statically link into the agent
-# shared library.  We still install libssl-dev above since getting libcurl to
-# link with the custom version is tricky, see
-# http://askubuntu.com/questions/475670/how-to-build-curl-with-the-latest-openssl.
-# Also, intentionally not using -j as OpenSSL < 1.1.0 not quite supporting the
-# parallel builds, see
-# https://github.com/openssl/openssl/issues/5762#issuecomment-376622684.
-RUN mkdir /tmp/openssl && cd /tmp/openssl && \
-    curl -sL https://www.openssl.org/source/openssl-1.0.2o.tar.gz | \
-        tar xzv --strip=1 && \
-    ./config no-shared -fPIC --openssldir=/usr/local/ssl && \
-    make && make install_sw && \
-    cd ~ && rm -rf /tmp/openssl
-
 # gRPC & protobuf
 # Use the protobuf version from gRPC for everything to avoid conflicting
 # versions to be linked in. Disable OpenSSL embedding: when it's on, the build
 # process of gRPC puts the OpenSSL static object files into the gRPC archive
 # which causes link errors later when the agent is linked with the static
 # OpenSSL library itself.
-RUN git clone --depth=1 --recursive -b v1.25.0 https://github.com/grpc/grpc.git /tmp/grpc && \
+RUN git clone --depth=1 --recursive -b v1.28.1 https://github.com/grpc/grpc.git /tmp/grpc && \
     cd /tmp/grpc && \
     cd third_party/protobuf && \
     ./autogen.sh && \
     ./configure --with-pic CXXFLAGS="$(pkg-config --cflags protobuf)" LIBS="$(pkg-config --libs protobuf)" LDFLAGS="-Wl,--no-as-needed" && \
     make -j && make install && ldconfig && \
     cd ../.. && \
-    CPPFLAGS="-I /usr/local/ssl/include" LDFLAGS="-Wl,--no-as-needed" make -j CONFIG=opt EMBED_OPENSSL=false V=1 HAS_SYSTEM_OPENSSL_NPN=0 && \
-    CPPFLAGS="-I /usr/local/ssl/include" LDFLAGS="-Wl,--no-as-needed" make CONFIG=opt EMBED_OPENSSL=false V=1 HAS_SYSTEM_OPENSSL_NPN=0 install && \
+    CPPFLAGS="-I /usr/local/ssl/include" LDFLAGS="-L /usr/local/ssl/lib/ -Wl,--no-as-needed" make -j CONFIG=opt EMBED_OPENSSL=false V=1 HAS_SYSTEM_OPENSSL_NPN=0 && \
+    CPPFLAGS="-I /usr/local/ssl/include" LDFLAGS="-L /usr/local/ssl/lib/ -Wl,--no-as-needed" make CONFIG=opt EMBED_OPENSSL=false V=1 HAS_SYSTEM_OPENSSL_NPN=0 install && \
     rm -rf /tmp/grpc

Makefile

@@ -174,6 +174,21 @@ GRPC_LIBS= \
   $(LIB_ROOT_PATH)/lib/libgrpc.a \
   $(LIB_ROOT_PATH)/lib/libgpr.a \
 
+# Detect if running on Alpine and modify various flags
+ifeq ("$(wildcard /etc/alpine-release)","/etc/alpine-release")
+  # musl only supports global dynamic tls model, and is documented as
+  # async-signal-safe. See
+  # https://wiki.musl-libc.org/design-concepts.html#Thread-local-storage
+  # This selects global-dynamic TLS model in
+  # third_party/javaprofiler/accessors.h
+  CFLAGS += -DALPINE
+
+  LIBS1 += /usr/lib/libexecinfo.a
+
+  # libgcc is not installed by default on Alpine.
+  LDFLAGS += -static-libgcc
+endif
+
 all: \
 	$(TARGET_AGENT) \
 	$(TARGET_NOTICES) \

README.md

@@ -1,7 +1,7 @@
-# Stackdriver Profiler Java Agent
+# Google Cloud Profiler Profiler Java Agent
 
-This repository contains source code for the [Stackdriver
-Profiler](https://cloud.google.com/profiler/) Java agent.
+This repository contains source code for the
+[Google Cloud Profiler Profiler](https://cloud.google.com/profiler/) Java agent.
 
 ## Installation
 
@@ -12,9 +12,9 @@ wget -q -O- https://storage.googleapis.com/cloud-profiler/java/latest/profiler_j
 | sudo tar xzv -C /opt/cprof
 ```
 
-See the [Stackdriver Profiler Java profiling
-doc](https://cloud.google.com/profiler/docs/profiling-java) for detailed and
-most up-to-date guide on installing and using the agent.
+See the
+[Google Cloud Profiler Profiler Java profiling doc](https://cloud.google.com/profiler/docs/profiling-java)
+for detailed and most up-to-date guide on installing and using the agent.
 
 ## Build from Source
 
@@ -27,3 +27,15 @@ commands below.
  $ cd cloud-profiler-java
  $ ./build.sh
 ```
+
+## To build for Alpine.
+
+**Per thread timers are not available on Alpine.** Since SIGEV_THREAD_ID is not
+supported by `timer_create` on Alpine, per thread timers are not implemented and
+the flag `-cprof_cpu_use_per_thread_timers` is ignored on this platform.
+
+```shell
+$ git clone https://github.com/GoogleCloudPlatform/cloud-profiler-java.git
+$ cd cloud-profiler-java
+$ ./build.sh -a
+```

build.sh

@@ -22,8 +22,14 @@ set -o nounset
 # Command line arguments: [-d]
 #   -d: specify the temporary directory for the build.
 
-while getopts ":d:" opt; do
+ALPINE_BUILD="0"
+DOCKERFILE="Dockerfile"
+FILE_SUFFIX=""
+while getopts ":ad:" opt; do
   case $opt in
+  a)
+      ALPINE_BUILD="1"
+      ;;
   d)
       BUILD_TEMP_DIR=$OPTARG
       ;;
@@ -57,8 +63,14 @@ trap "{ echo 'FAILED: see ${LOG_FILE} for details' ; exit 1; }" ERR
 
 mkdir -p "${BUILD_TEMP_DIR}"
 
-PrintMessage "Building the builder Docker container..."
-docker build -t cprof-agent-builder . >> "${LOG_FILE}" 2>&1
+if [[ "${ALPINE_BUILD}" = "1" ]]; then
+    PrintMessage "Building the builder Alpine Docker container..."
+    DOCKERFILE="Dockerfile.alpine"
+    FILE_SUFFIX="_alpine"
+else
+    PrintMessage "Building the builder Docker container..."
+fi
+    docker build -f "${DOCKERFILE}" -t cprof-agent-builder . >> "${LOG_FILE}" 2>&1
 
 PrintMessage "Packaging the agent code..."
 mkdir -p "${BUILD_TEMP_DIR}"/build
@@ -72,12 +84,12 @@ docker run -ti -v "${BUILD_TEMP_DIR}/build":/root/build \
     >> "${LOG_FILE}" 2>&1
 
 PrintMessage "Packaging the agent binaries..."
-tar zcf "${BUILD_TEMP_DIR}"/profiler_java_agent.tar.gz \
+tar zcf "${BUILD_TEMP_DIR}"/profiler_java_agent${FILE_SUFFIX}.tar.gz \
     -C "${BUILD_TEMP_DIR}"/build/.out \
     NOTICES profiler_java_agent.so \
     >> "${LOG_FILE}" 2>&1
 
-PrintMessage "Agent built and stored locally in: ${BUILD_TEMP_DIR}/profiler_java_agent.tar.gz"
+PrintMessage "Agent built and stored locally in: ${BUILD_TEMP_DIR}/profiler_java_agent${FILE_SUFFIX}.tar.gz"
 
 trap - EXIT
 PrintMessage "SUCCESS"

src/NOTICES

@@ -1,4 +1,4 @@
-Google Stackdriver Profiler
+Google Cloud Profiler
 Copyright Google Inc.
 Use of this software is governed by the Google Cloud Platform Terms of Service
 found at https://cloud.google.com/terms/
@@ -470,4 +470,3 @@ OpenSSL License
  * copied and put under another distribution licence
  * [including the GNU Public Licence.]
  */
-

src/cloud_env.cc

@@ -88,7 +88,7 @@ std::string GceMetadataRequest(HTTPRequest* req, const std::string& path) {
 }
 
 const char* Getenv(const std::string& var) {
-#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 17)
+#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 17) || ALPINE == 1
   return secure_getenv(var.c_str());
 #else
   return __secure_getenv(var.c_str());

src/entry.cc

@@ -26,7 +26,8 @@
 
 DEFINE_bool(cprof_cpu_use_per_thread_timers, false,
             "when true, use per-thread CLOCK_THREAD_CPUTIME_ID timers; "
-            "only profiles Java threads, non-Java threads will be missed");
+            "only profiles Java threads, non-Java threads will be missed. "
+            "This flag is ignored on Alpine.");
 DEFINE_bool(cprof_force_debug_non_safepoints, true,
             "when true, force DebugNonSafepoints flag by subscribing to the"
             "code generation events. This improves the accuracy of profiles,"
@@ -267,7 +268,7 @@ jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
 
   ParseArguments(options);  // Initializes logger -- do not log before this call
 
-  LOG(INFO) << "Stackdriver Profiler Java agent version: "
+  LOG(INFO) << "Google Cloud Profiler Java agent version: "
             << CLOUD_PROFILER_AGENT_VERSION;
   LOG(INFO) << "Profiler agent loaded";
   google::javaprofiler::AttributeTable::Init();
@@ -292,7 +293,16 @@ jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
   // The process exit will free the memory. See comments to the variable on why.
   // Initialize before registering the JVMTI callbacks to avoid the unlikely
   // race of getting thread events before the thread table is born.
+#ifdef ALPINE
+  // musl does not support SIGEV_THREAD_ID. Disable per thread timers.
+  if (FLAGS_cprof_cpu_use_per_thread_timers) {
+    LOG(WARNING) << "Per thread timers not available in Alpine. "
+                 << "Ignoring '-cprof_cpu_use_per_thread_timers' flag.";
+  }
+  threads = new ThreadTable(false);
+#else
   threads = new ThreadTable(FLAGS_cprof_cpu_use_per_thread_timers);
+#endif
 
   if (!RegisterJvmti(jvmti)) {
     LOG(ERROR) << "Failed to enable JVMTI events.  Continuing...";
@@ -304,21 +314,19 @@ jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
 
   google::javaprofiler::Asgct::SetAsgct(
       google::javaprofiler::Accessors::GetJvmFunction<
-      google::javaprofiler::ASGCTType>("AsyncGetCallTrace"));
+          google::javaprofiler::ASGCTType>("AsyncGetCallTrace"));
 
   worker = new Worker(jvmti, threads);
   return 0;
 }
 
-void JNICALL Agent_OnUnload(JavaVM *vm) {
-  IMPLICITLY_USE(vm);
-}
+void JNICALL Agent_OnUnload(JavaVM *vm) { IMPLICITLY_USE(vm); }
 
 }  // namespace profiler
 }  // namespace cloud
 
-AGENTEXPORT jint JNICALL
-Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
+AGENTEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options,
+                                      void *reserved) {
   return cloud::profiler::Agent_OnLoad(vm, options, reserved);
 }
 

src/threads.cc

@@ -27,6 +27,10 @@ namespace {
 const timer_t kInvalidTimer = reinterpret_cast<timer_t>(-1LL);
 
 timer_t CreateTimer(pid_t tid) {
+#ifdef ALPINE
+  // Per thread timers are not available on Alpine.
+  return kInvalidTimer;
+#else
   struct sigevent sevp = {};
   sevp.sigev_notify = SIGEV_THREAD_ID;
   sevp._sigev_un._tid = tid;
@@ -38,6 +42,7 @@ timer_t CreateTimer(pid_t tid) {
     return kInvalidTimer;
   }
   return timer;
+#endif
 }
 
 bool SetTimer(timer_t timer, int64_t period_usec) {

third_party/javaprofiler/accessors.h

@@ -80,15 +80,19 @@ class Accessors {
   }
 
  private:
-  // This is dangerous. TLS accesses are by default not async safe, as
-  // they can call malloc for lazy initialization. The initial-exec
-  // TLS mode avoids this potential allocation, with the limitation
-  // that there is a fixed amount of space to hold all TLS variables
-  // referenced in the module. This should be OK for the cloud
-  // profiler agent, which is relatively small. We do provide a way
-  // to override the TLS model for compilation environments where the
-  // TLS access is async-safe.
-#ifdef JAVAPROFILER_GLOBAL_DYNAMIC_TLS
+  // This is subtle and potentially dangerous, read this carefully.
+  //
+  // In glibc, TLS access is not signal-async-safe, as they can call malloc for
+  // lazy initialization. The initial-exec TLS mode avoids this potential
+  // allocation, with the limitation that there is a fixed amount of space to
+  // hold all TLS variables referenced in the module. This should be OK for the
+  // cloud profiler agent, which is relatively small.
+  //
+  // In environments where the TLS access is async-signal-safe, the
+  // global-dynamic TLS model can be used. For example, it is async-signal-safe
+  // in musl / Alpine, see
+  // https://wiki.musl-libc.org/design-concepts.html#Thread-local-storage.
+#if defined(JAVAPROFILER_GLOBAL_DYNAMIC_TLS) || defined(ALPINE)
   static __thread JNIEnv *env_ __attribute__((tls_model("global-dynamic")));
   static __thread int64 attr_ __attribute__((tls_model("global-dynamic")));
   static __thread Tags *tags_ __attribute__((tls_model("global-dynamic")));

third_party/javaprofiler/async_ref_counted_string.cc

@@ -23,11 +23,12 @@ namespace google {
 namespace javaprofiler {
 namespace {
 
-using StringRefCountTable = std::unordered_map<string, std::atomic<int32_t>>;
+using StringRefCountTable =
+    std::unordered_map<std::string, std::atomic<int32_t>>;
 using StringRefCount = StringRefCountTable::value_type;
 
 // Maps string to its reference count.
-std::unordered_map<string, std::atomic<int32_t>> *string_table = nullptr;
+std::unordered_map<std::string, std::atomic<int32_t>> *string_table = nullptr;
 // All accesses to string_table should be protected by string_table_mutex.
 std::mutex string_table_mutex;
 
@@ -47,7 +48,7 @@ std::mutex string_table_mutex;
 // Resolves the StringRefCount of a given string, increments the reference count
 // and returns the pointer of StringRefCount. It returns nullptr if the internal
 // string table is not initialized.
-StringRefCount *AcquireByString(const string &str) {
+StringRefCount *AcquireByString(const std::string &str) {
   std::lock_guard<std::mutex> lock(string_table_mutex);
   if (string_table == nullptr) {
     return nullptr;
@@ -114,7 +115,7 @@ void Release(StringRefCount *str_ref_cnt) {
 
 }  // namespace
 
-AsyncRefCountedString::AsyncRefCountedString(const string &str)
+AsyncRefCountedString::AsyncRefCountedString(const std::string &str)
     : AsyncRefCountedString() {
   Release(ptr_.exchange(AcquireByString(str)));
 }
@@ -128,7 +129,8 @@ AsyncRefCountedString::~AsyncRefCountedString() {
   Release(ptr_.exchange(nullptr));
 }
 
-AsyncRefCountedString &AsyncRefCountedString::operator=(const string &str) {
+AsyncRefCountedString &AsyncRefCountedString::operator=(
+    const std::string &str) {
   Release(ptr_.exchange(AcquireByString(str)));
   return *this;
 }
@@ -160,7 +162,7 @@ void AsyncRefCountedString::AsyncSafeReset() {
   assert(AsyncSafeRelease(ptr_.exchange(nullptr)));
 }
 
-const string *AsyncRefCountedString::Get() const {
+const std::string *AsyncRefCountedString::Get() const {
   StringRefCount *str_ref_cnt = ptr_.load();
   if (str_ref_cnt == nullptr) {
     return nullptr;
@@ -172,7 +174,7 @@ const string *AsyncRefCountedString::Get() const {
 bool AsyncRefCountedString::Init() {
   std::lock_guard<std::mutex> lock(string_table_mutex);
   if (string_table == nullptr) {
-    string_table = new std::unordered_map<string, std::atomic<int32_t>>();
+    string_table = new std::unordered_map<std::string, std::atomic<int32_t>>();
     return true;
   }
   return false;