On Mon, 17 Mar 2025 18:26:57 GMT, Larry Cable <d...@openjdk.org> wrote:
> on both Linux and MacOS libattach utilizes UNIX signal (QUIT) to cause a > target JVM (attachee) to create the socket file used as transport for > subsequent jcmds (and other attach based interactions) and to listen upon > that for such. > > it should be noted that the default behavior for QUIT (if not blocked or > caught) is to terminate the signalled process. > > during the early lifetime of a JVM, its signal handlers are not yet > installed, and thus any signal such as QUIT will cause the > default behavior to occur, in this case the JVM will be terminated. > > this is why some tests are failing with "not alive" > > the "fix" is similar in nature to that already implemented for linux (however > using a different OS dependent mechanism to obtain the attachee JVM's signal > masks: sysctl(2)). > > the method "checkCatchesAndSendQuitTo" will now obtain the "attachee" JVM > signal masks and only kill(QUIT) if the > current masks indicate that the JVM's signals are now being handled. > > the behavior in the success case is now identical to the previous > implementation, however should the target JVM not > become "ready" (signal handlers installed) prior to the attach "timeout" > occurring the attach operation will throw an > "AttachNotSupportedException" with a suitable error message. > > see also: https://bugs.openjdk.org/browse/JDK-8350766 src/jdk.attach/macosx/native/libattach/VirtualMachineImpl.c line 157: > 155: snprintf(msg, sizeof(msg), "pid: %d, state is not ready to > participate in attach handshake!", (int)pid); > 156: > 157: JNU_ThrowByName(env, > "com/sun/tools/attach/AttachNotSupportedException", msg); I am not too familiar with JNI. Would it be cleaner/beneficial if this native method just returned `JNI_TRUE`/`JNI_FALSE` to indicate whether or not the `SIGQUIT` was sent and then in the Java code side, handle the `throwIfNotReady` part and create and throw the exception if this function returned `JNI_FALSE` and `throwIfNotReady` was `true`? Would there be any benefit of doing that in the Java side instead of here? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/24085#discussion_r2015747468
