--- old/src/hotspot/share/runtime/os.cpp	2019-08-09 17:37:06.492826101 +0100
+++ new/src/hotspot/share/runtime/os.cpp	2019-08-09 17:37:05.788810321 +0100
@@ -1349,7 +1349,7 @@
   for (int i = 0 ; i < count ; i++) {
     size_t len = strcspn(p, os::path_separator());
     if (len > JVM_MAXPATHLEN) {
-      return NULL;
+      //return NULL;
     }
     // allocate the string and add terminator storage
     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
--- old/src/jdk.jdwp.agent/unix/native/libjdwp/linker_md.c	2019-08-09 17:37:07.516849054 +0100
+++ new/src/jdk.jdwp.agent/unix/native/libjdwp/linker_md.c	2019-08-09 17:37:07.000837488 +0100
@@ -34,6 +34,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "util.h"
 #include "path_md.h"
 
 #ifdef __APPLE__
@@ -45,6 +46,7 @@
 static void dll_build_name(char* buffer, size_t buflen,
                            const char* paths, const char* fname) {
     char *path, *paths_copy, *next_token;
+    *buffer = '\0';
 
     paths_copy = strdup(paths);
     if (paths_copy == NULL) {
@@ -55,8 +57,11 @@
     path = strtok_r(paths_copy, PATH_SEPARATOR, &next_token);
 
     while (path != NULL) {
-        snprintf(buffer, buflen, "%s/lib%s." LIB_SUFFIX, path, fname);
-        if (access(buffer, F_OK) == 0) {
+        size_t result_len = (size_t)snprintf(buffer, buflen, "%s/lib%s." LIB_SUFFIX, path, fname);
+        if (result_len >= buflen) {
+            EXIT_ERROR(JVMTI_ERROR_INVALID_LOCATION, "One or more of the library paths supplied to jdwp, "
+                                                     "likely by sun.boot.library.path, is too long.");
+        } else if (access(buffer, F_OK) == 0) {
             break;
         }
         *buffer = '\0';
@@ -89,13 +94,11 @@
 {
     const int pnamelen = pname ? strlen(pname) : 0;
 
-    *holder = '\0';
-    // Quietly truncate on buffer overflow.  Should be an error.
-    if (pnamelen + (int)strlen(fname) + 10 > holderlen) {
-        return;
-    }
-
     if (pnamelen == 0) {
+        if (pnamelen + (int)strlen(fname) + 10 > holderlen) {
+            EXIT_ERROR(JVMTI_ERROR_INVALID_LOCATION, "One or more of the library paths supplied to jdwp, "
+                                                     "likely by sun.boot.library.path, is too long.");
+        }
         (void)snprintf(holder, holderlen, "lib%s." LIB_SUFFIX, fname);
     } else {
       dll_build_name(holder, holderlen, pname, fname);
--- old/src/jdk.jdwp.agent/windows/native/libjdwp/linker_md.c	2019-08-09 17:37:08.516871467 +0100
+++ new/src/jdk.jdwp.agent/windows/native/libjdwp/linker_md.c	2019-08-09 17:37:07.988859632 +0100
@@ -37,11 +37,13 @@
 
 #include "sys.h"
 
+#include "util.h"
 #include "path_md.h"
 
 static void dll_build_name(char* buffer, size_t buflen,
                            const char* paths, const char* fname) {
     char *path, *paths_copy, *next_token;
+    *buffer = '\0';
 
     paths_copy = strdup(paths);
     if (paths_copy == NULL) {
@@ -52,8 +54,11 @@
     path = strtok_s(paths_copy, PATH_SEPARATOR, &next_token);
 
     while (path != NULL) {
-        _snprintf(buffer, buflen, "%s\\%s.dll", path, fname);
-        if (_access(buffer, 0) == 0) {
+        size_t result_len = (size_t)_snprintf(buffer, buflen, "%s\\%s.dll", path, fname);
+        if (result_len >= buflen) {
+            EXIT_ERROR(JVMTI_ERROR_INVALID_LOCATION, "One or more of the library paths supplied to jdwp, "
+                                                     "likely by sun.boot.library.path, is too long.");
+        } else if (_access(buffer, 0) == 0) {
             break;
         }
         *buffer = '\0';
@@ -107,13 +112,11 @@
 {
     const int pnamelen = pname ? (int)strlen(pname) : 0;
 
-    *holder = '\0';
-    /* Quietly truncates on buffer overflow. Should be an error. */
-    if (pnamelen + (int)strlen(fname) + 10 > holderlen) {
-        return;
-    }
-
     if (pnamelen == 0) {
+        if (pnamelen + (int)strlen(fname) + 10 > holderlen) {
+            EXIT_ERROR(JVMTI_ERROR_INVALID_LOCATION, "One or more of the library paths supplied to jdwp, "
+                                                     "likely by sun.boot.library.path, is too long.");
+        }
         sprintf(holder, "%s.dll", fname);
     } else {
       dll_build_name(holder, holderlen, pname, fname);