--- src/jdk.management/unix/native/libmanagement_ext/OperatingSystemImpl.c.orig	2025-01-07 14:27:42 UTC
+++ src/jdk.management/unix/native/libmanagement_ext/OperatingSystemImpl.c
@@ -32,6 +32,9 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#if defined(__FreeBSD__)
+#include <sys/user.h>
+#endif
 #if defined(_ALLBSD_SOURCE)
 #include <sys/sysctl.h>
 #ifdef __APPLE__
@@ -178,23 +181,48 @@ Java_com_sun_management_internal_OperatingSystemImpl_g
     }
     return t_info.virtual_size;
 #elif defined(__FreeBSD__)
-    FILE *fp;
-    unsigned long end, start;
+    int mib[4];
+    int error;
+    int cnt;
+    size_t len;
+    char *buf, *bp, *eb;
     jlong total = 0;
 
-    if ((fp = fopen("/proc/curproc/map", "r")) == NULL) {
-        throw_internal_error(env, "Unable to open /proc/curproc/map");
-        return -1;
+    len = 0;
+    mib[0] = CTL_KERN;
+    mib[1] = KERN_PROC;
+    mib[2] = KERN_PROC_VMMAP;
+    mib[3] = getpid();
+
+    error = sysctl(mib, nitems(mib), NULL, &len, NULL, 0);
+    if (error) {
+        throw_internal_error(env, "Unable to open kern.proc.vmmap");
+       return (-1);
     }
 
-    for (;;) {
-       // Ignore everything except start and end entries
-       if (fscanf(fp, "0x%lx 0x%lx %*[^\n]\n", &start, &end) != 2 || start > end)
-           break;
-       total += end - start;
+    len = len * 4 / 3;
+    buf=malloc(len);
+    if (buf == NULL) {
+            throw_internal_error(env, "Unable to allocate memory");
+            return -1;
     }
 
-    fclose(fp);
+    error = sysctl(mib, nitems(mib), buf, &len, NULL, 0);
+    if (error) {
+	    free(buf);
+            throw_internal_error(env, "Unable to allocate memory");
+            return -1;
+    }
+    bp = buf;
+    eb = buf + len;
+    while (bp < eb) {
+	    struct kinfo_vmentry *kv = (struct kinfo_vmentry *)(uintptr_t)bp;
+	    if (kv->kve_structsize == 0)
+		    break;
+	    bp += kv->kve_structsize;
+	    total += kv->kve_end - kv->kve_start;
+    }
+    free(buf);
     return total;
 #else /* _ALLBSD_SOURCE */
     /*
@@ -402,6 +430,22 @@ Java_com_sun_management_internal_OperatingSystemImpl_g
     free(fds);
 
     return nfiles;
+#elif defined(__FreeBSD__)
+    int mib[4];
+    int error;
+    int nfds;
+    size_t len;
+
+    len = sizeof(nfds);
+    mib[0] = CTL_KERN;
+    mib[1] = KERN_PROC;
+    mib[2] = KERN_PROC_NFDS;
+    mib[3] = 0;
+
+    if (sysctl(mib, 4, &nfds, &len, NULL, 0) == -1)
+	    return -1;
+    return nfds;
+
 #elif defined(__OpenBSD__)
     return getdtablecount();
 #else /* solaris/linux */