From 7e879bcae45b7a7e4b3fa8044564e3590344dbbd Mon Sep 17 00:00:00 2001
Date: Fri, 22 Jan 2021 16:23:51 +0800
Subject: recreate .java_pid file when deleted for attach
mechanism
Summary: <hotspot>: <enable attach mechanism when .java_pid is lost>
LLT:
Bug url:
---
.../src/os/linux/vm/attachListener_linux.cpp | 20 +++++++++++++++----
.../src/share/vm/services/attachListener.cpp | 1 +
.../src/share/vm/services/attachListener.hpp | 2 +-
3 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/hotspot/src/os/linux/vm/attachListener_linux.cpp b/hotspot/src/os/linux/vm/attachListener_linux.cpp
index 700a09ff0..1ca089740 100644
--- a/hotspot/src/os/linux/vm/attachListener_linux.cpp
+++ b/hotspot/src/os/linux/vm/attachListener_linux.cpp
@@ -485,13 +485,25 @@ bool AttachListener::init_at_startup() {
// If the file .attach_pid<pid> exists in the working directory
// or /tmp then this is the trigger to start the attach mechanism
bool AttachListener::is_init_trigger() {
- if (init_at_startup() || is_initialized()) {
- return false; // initialized at startup or already initialized
+ if (init_at_startup()) {
+ return false; // initialized at startup
}
- char fn[PATH_MAX+1];
- sprintf(fn, ".attach_pid%d", os::current_process_id());
+
+ char fn[PATH_MAX + 1];
int ret;
struct stat64 st;
+
+ // check initialized
+ if (is_initialized()) {
+ // check .java_pid file exists
+ RESTARTABLE(::stat64(LinuxAttachListener::path(), &st), ret);
+ if (ret == -1) {
+ ::shutdown(LinuxAttachListener::listener(), SHUT_RDWR);
+ }
+ return false;
+ }
+
+ sprintf(fn, ".attach_pid%d", os::current_process_id());
RESTARTABLE(::stat64(fn, &st), ret);
if (ret == -1) {
snprintf(fn, sizeof(fn), "%s/.attach_pid%d",
diff --git a/hotspot/src/share/vm/services/attachListener.cpp b/hotspot/src/share/vm/services/attachListener.cpp
index 59b2f5483..0f51378dd 100644
--- a/hotspot/src/share/vm/services/attachListener.cpp
+++ b/hotspot/src/share/vm/services/attachListener.cpp
@@ -425,6 +425,7 @@ static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
for (;;) {
AttachOperation* op = AttachListener::dequeue();
if (op == NULL) {
+ AttachListener::set_initialized(false);
return; // dequeue failed or shutdown
}
diff --git a/hotspot/src/share/vm/services/attachListener.hpp b/hotspot/src/share/vm/services/attachListener.hpp
index 5204c4c62..11ec525c6 100644
--- a/hotspot/src/share/vm/services/attachListener.hpp
+++ b/hotspot/src/share/vm/services/attachListener.hpp
@@ -71,7 +71,7 @@ class AttachListener: AllStatic {
public:
static bool is_initialized() { return _initialized; }
- static void set_initialized() { _initialized = true; }
+ static void set_initialized(bool init = true) { _initialized = init; }
// indicates if this VM supports attach-on-demand
static bool is_attach_supported() { return !DisableAttachMechanism; }
--
2.19.0