8284726: Print active locale settings in hs_err reports and in VM.info

Reviewed-by: dholmes, mbaesken, kevinw

src/hotspot/os/posix/os_posix.cpp

@@ -53,6 +53,7 @@
 #include <dirent.h>
 #include <dlfcn.h>
 #include <grp.h>
+#include <locale.h>
 #include <netdb.h>
 #include <pwd.h>
 #include <pthread.h>
@@ -548,6 +549,33 @@ void os::Posix::print_user_info(outputStream* st) {
   st->cr();
 }
 
+// Print all active locale categories, one line each
+void os::Posix::print_active_locale(outputStream* st) {
+  st->print_cr("Active Locale:");
+  // Posix is quiet about how exactly LC_ALL is implemented.
+  // Just print it out too, in case LC_ALL is held separately
+  // from the individual categories.
+  #define LOCALE_CAT_DO(f) \
+    f(LC_ALL) \
+    f(LC_COLLATE) \
+    f(LC_CTYPE) \
+    f(LC_MESSAGES) \
+    f(LC_MONETARY) \
+    f(LC_NUMERIC) \
+    f(LC_TIME)
+  #define XX(cat) { cat, #cat },
+  const struct { int c; const char* name; } categories[] = {
+      LOCALE_CAT_DO(XX)
+      { -1, NULL }
+  };
+  #undef XX
+  #undef LOCALE_CAT_DO
+  for (int i = 0; categories[i].c != -1; i ++) {
+    const char* locale = setlocale(categories[i].c, NULL);
+    st->print_cr("%s=%s", categories[i].name,
+                 ((locale != NULL) ? locale : "<unknown>"));
+  }
+}
 
 bool os::get_host_name(char* buf, size_t buflen) {
   struct utsname name;

src/hotspot/os/posix/os_posix.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2022, 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
@@ -104,6 +104,8 @@ public:
   static bool handle_stack_overflow(JavaThread* thread, address addr, address pc,
                                     const void* ucVoid,
                                     address* stub);
+
+  static void print_active_locale(outputStream* st);
 };
 
 /*

src/hotspot/share/utilities/vmError.cpp

@@ -1146,6 +1146,15 @@ void VMError::report(outputStream* st, bool _verbose) {
        st->cr();
      }
 
+#ifndef _WIN32
+  STEP("printing locale settings")
+
+     if (_verbose) {
+       os::Posix::print_active_locale(st);
+       st->cr();
+     }
+#endif
+
   STEP("printing signal handlers")
 
      if (_verbose) {
@@ -1327,6 +1336,12 @@ void VMError::print_vm_info(outputStream* st) {
   os::print_environment_variables(st, env_list);
   st->cr();
 
+  // STEP("printing locale settings")
+#ifndef _WIN32
+  os::Posix::print_active_locale(st);
+  st->cr();
+#endif
+
   // STEP("printing signal handlers")
 
   os::print_signal_handlers(st, buf, sizeof(buf));