8299665: /proc/self/stat parsing in libmanagement broken by execname with spaces

Reviewed-by: sspitsyn, amenkov

src/jdk.management/linux/native/libmanagement_ext/UnixOperatingSystem.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2023, 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
@@ -36,6 +36,8 @@
 #include <dlfcn.h>
 #include <pthread.h>
 #include <inttypes.h>
+
+#include "management_ext.h"
 #include "com_sun_management_internal_OperatingSystemImpl.h"
 
 #include <assert.h>
@@ -331,6 +333,26 @@ double get_process_load() {
     return u + s;
 }
 
+static long read_vmem_usage(const char *procfile, unsigned long *vsize) {
+    int n = read_statdata(procfile, "%*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %*d %*d %*d %*d %*d %*d %*u %*u %*d %lu %*[^\n]\n", vsize);
+    if (n != 1) {
+        return -1;
+    } else {
+        return *vsize;
+    }
+}
+
+JNIEXPORT jlong JNICALL
+Java_com_sun_management_internal_OperatingSystemImpl_getCommittedVirtualMemorySize0
+  (JNIEnv *env, jobject mbean)
+{
+    unsigned long vsize;
+    if (read_vmem_usage("/proc/self/stat", &vsize) == -1) {
+        throw_internal_error(env, "Unable to get virtual memory usage");
+    }
+    return (jlong) vsize;
+}
+
 JNIEXPORT jdouble JNICALL
 Java_com_sun_management_internal_OperatingSystemImpl_getCpuLoad0
 (JNIEnv *env, jobject dummy)

src/jdk.management/share/native/libmanagement_ext/management_ext.c

@@ -35,6 +35,13 @@ const JmmInterface* jmm_interface_management_ext = NULL;
 static JavaVM* jvm = NULL;
 jint jmm_version_management_ext = 0;
 
+void throw_internal_error(JNIEnv* env, const char* msg) {
+    char errmsg[128];
+
+    snprintf(errmsg, sizeof(errmsg), "errno: %d error: %s\n", errno, msg);
+    JNU_ThrowInternalError(env, errmsg);
+}
+
 JNIEXPORT jint JNICALL
    DEF_JNI_OnLoad(JavaVM *vm, void *reserved) {
     JNIEnv* env;

src/jdk.management/share/native/libmanagement_ext/management_ext.h

@@ -37,4 +37,6 @@
 extern const JmmInterface* jmm_interface_management_ext;
 extern jint jmm_version_management_ext;
 
+void throw_internal_error(JNIEnv* env, const char* msg);
+
 #endif

src/jdk.management/unix/native/libmanagement_ext/OperatingSystemImpl.c

@@ -82,13 +82,6 @@ static jlong page_size = 0;
   #define closedir closedir64
 #endif
 
-static void throw_internal_error(JNIEnv* env, const char* msg) {
-    char errmsg[128];
-
-    snprintf(errmsg, sizeof(errmsg), "errno: %d error: %s\n", errno, msg);
-    JNU_ThrowInternalError(env, errmsg);
-}
-
 // true = get available swap in bytes
 // false = get total swap in bytes
 static jlong get_total_or_available_swap_space_size(JNIEnv* env, jboolean available) {
@@ -129,29 +122,13 @@ Java_com_sun_management_internal_OperatingSystemImpl_initialize0
     page_size = sysconf(_SC_PAGESIZE);
 }
 
+// Linux-specific implementation is in UnixOperatingSystem.c
+#if !defined(__linux__)
 JNIEXPORT jlong JNICALL
 Java_com_sun_management_internal_OperatingSystemImpl_getCommittedVirtualMemorySize0
   (JNIEnv *env, jobject mbean)
 {
-#if defined(__linux__)
-    FILE *fp;
-    unsigned long vsize = 0;
-
-    if ((fp = fopen("/proc/self/stat", "r")) == NULL) {
-        throw_internal_error(env, "Unable to open /proc/self/stat");
-        return -1;
-    }
-
-    // Ignore everything except the vsize entry
-    if (fscanf(fp, "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %*d %*d %*d %*d %*d %*d %*u %*u %*d %lu %*[^\n]\n", &vsize) == EOF) {
-        throw_internal_error(env, "Unable to get virtual memory usage");
-        fclose(fp);
-        return -1;
-    }
-
-    fclose(fp);
-    return (jlong)vsize;
-#elif defined(__APPLE__)
+#if defined(__APPLE__)
     struct task_basic_info t_info;
     mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
 
@@ -168,6 +145,7 @@ Java_com_sun_management_internal_OperatingSystemImpl_getCommittedVirtualMemorySi
     return (64 * MB);
 #endif
 }
+#endif
 
 JNIEXPORT jlong JNICALL
 Java_com_sun_management_internal_OperatingSystemImpl_getTotalSwapSpaceSize0