8353439: Shell grouping of -XX:OnError= commands is surprising

Reviewed-by: dholmes, stuefe

Author: kevinjwalls

src/hotspot/share/utilities/vmError.cpp

@@ -136,7 +136,9 @@ static const char* env_list[] = {
   nullptr                       // End marker.
 };
 
-// A simple parser for -XX:OnError, usage:
+// A simple parser for lists of commands such as -XX:OnError and -XX:OnOutOfMemoryError
+// Command list (ptr) is expected to be a sequence of commands delineated by semicolons and/or newlines.
+// Usage:
 //  ptr = OnError;
 //  while ((cmd = next_OnError_command(buffer, sizeof(buffer), &ptr) != nullptr)
 //     ... ...
@@ -145,13 +147,13 @@ static char* next_OnError_command(char* buf, int buflen, const char** ptr) {
 
   const char* cmd = *ptr;
 
-  // skip leading blanks or ';'
-  while (*cmd == ' ' || *cmd == ';') cmd++;
+  // skip leading blanks, ';' or newlines
+  while (*cmd == ' ' || *cmd == ';' || *cmd == '\n') cmd++;
 
   if (*cmd == '\0') return nullptr;
 
   const char * cmdend = cmd;
-  while (*cmdend != '\0' && *cmdend != ';') cmdend++;
+  while (*cmdend != '\0' && *cmdend != ';' && *cmdend != '\n') cmdend++;
 
   Arguments::copy_expand_pid(cmd, cmdend - cmd, buf, buflen);
 

test/hotspot/jtreg/runtime/ErrorHandling/TestOnError.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,10 @@ public class TestOnError {
 
     public static void main(String[] args) throws Exception {
         String msg = "Test Succeeded";
+        String msg1 = "OnError Test Message1";
+        String msg2 = "OnError Test Message2";
 
+        // Basic OnError test:
         ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder(
            "-XX:-CreateCoredumpOnCrash",
            "-XX:ErrorHandlerTest=14", // trigger potential SEGV
@@ -59,6 +62,30 @@ public static void main(String[] args) throws Exception {
            both get written to stdout.
         */
         output.stdoutShouldMatch("^" + msg); // match start of line only
+
+        // Test multiple OnError arguments:
+        pb = ProcessTools.createLimitedTestJavaProcessBuilder(
+           "-XX:-CreateCoredumpOnCrash",
+           "-XX:ErrorHandlerTest=14",
+           "-XX:OnError=echo " + msg1,
+           "-XX:OnError=echo " + msg2,
+           TestOnError.class.getName());
+
+        output = new OutputAnalyzer(pb.start());
+        output.stdoutShouldMatch("^" + msg1);
+        output.stdoutShouldMatch("^" + msg2);
+
+        // Test one argument with multiple commands using ; separator:
+        pb = ProcessTools.createLimitedTestJavaProcessBuilder(
+           "-XX:-CreateCoredumpOnCrash",
+           "-XX:ErrorHandlerTest=14",
+           "-XX:OnError=echo " + msg1 + ";echo " + msg2,
+           TestOnError.class.getName());
+
+        output = new OutputAnalyzer(pb.start());
+        output.stdoutShouldMatch("^" + msg1);
+        output.stdoutShouldMatch("^" + msg2);
+
         System.out.println("PASSED");
     }
 }