commit aebb4e5d8d021a1dbac3dd925e3ec3535ea84a68
Author: Kamil Rytarowski <n54@gmx.com>
Date:   Fri Jun 7 23:42:03 2019 +0200

    Implement native proc_cwd for NetBSD without /proc (Linux-compat)
    
    KERN_PROC_CWD has been introduced in NetBSD 8.99.42.

diff --git a/psutil/_psbsd.py b/psutil/_psbsd.py
index 3d9dfdab..1ce1a5ff 100644
--- a/psutil/_psbsd.py
+++ b/psutil/_psbsd.py
@@ -105,6 +105,7 @@ HAS_PER_CPU_TIMES = hasattr(cext, "per_cpu_times")
 HAS_PROC_NUM_THREADS = hasattr(cext, "proc_num_threads")
 HAS_PROC_OPEN_FILES = hasattr(cext, 'proc_open_files')
 HAS_PROC_NUM_FDS = hasattr(cext, 'proc_num_fds')
+HAS_PROC_CWD = hasattr(cext, 'proc_cwd')
 
 kinfo_proc_map = dict(
     ppid=0,
@@ -845,6 +846,8 @@ class Process(object):
         if OPENBSD and self.pid == 0:
             return None  # ...else it would raise EINVAL
         elif NETBSD:
+            if HAS_PROC_CWD:
+                return cext.proc_cwd(self.pid) or None
             with wrap_exceptions_procfs(self):
                 return os.readlink("/proc/%s/cwd" % self.pid)
         elif HAS_PROC_OPEN_FILES:
diff --git a/psutil/_psutil_bsd.c b/psutil/_psutil_bsd.c
index 0f899ef5..88f168d3 100644
--- a/psutil/_psutil_bsd.c
+++ b/psutil/_psutil_bsd.c
@@ -921,6 +921,8 @@ PsutilMethods[] = {
 #if defined(PSUTIL_FREEBSD) || defined(PSUTIL_OPENBSD)
     {"proc_connections", psutil_proc_connections, METH_VARARGS,
      "Return connections opened by process"},
+#endif
+#if defined(PSUTIL_FREEBSD) || defined(PSUTIL_OPENBSD) || (defined(PSUTIL_NETBSD) && __NetBSD_Version__ >= 899004200)
     {"proc_cwd", psutil_proc_cwd, METH_VARARGS,
      "Return process current working directory."},
 #endif
diff --git a/psutil/arch/netbsd/specific.c b/psutil/arch/netbsd/specific.c
index 195896f2..c4edad31 100644
--- a/psutil/arch/netbsd/specific.c
+++ b/psutil/arch/netbsd/specific.c
@@ -111,6 +111,24 @@ kinfo_getfile(pid_t pid, int* cnt) {
     return kf;
 }
 
+#ifdef KERN_PROC_CWD /* Introduced in NetBSD-8.99.42 */
+PyObject *
+psutil_proc_cwd(PyObject *self, PyObject *args) {
+    long pid;
+    char path[MAXPATHLEN];
+    size_t pathlen = sizeof path;
+
+    if (! PyArg_ParseTuple(args, "l", &pid))
+        return NULL;
+
+    int name[] = { CTL_KERN, KERN_PROC_ARGS, pid, KERN_PROC_CWD};
+    if (sysctl(name, 4, path, &pathlen, NULL, 0) != 0) {
+        PyErr_SetFromErrno(PyExc_OSError);
+        return NULL;
+    }
+    return PyUnicode_DecodeFSDefault(path);
+}
+#endif
 
 // XXX: This is no longer used as per
 // https://github.com/giampaolo/psutil/pull/557#issuecomment-171912820
diff --git a/psutil/arch/netbsd/specific.h b/psutil/arch/netbsd/specific.h
index 96ad9f7d..7dac88f7 100644
--- a/psutil/arch/netbsd/specific.h
+++ b/psutil/arch/netbsd/specific.h
@@ -26,3 +26,6 @@ PyObject* psutil_disk_io_counters(PyObject* self, PyObject* args);
 PyObject* psutil_proc_exe(PyObject* self, PyObject* args);
 PyObject* psutil_proc_num_threads(PyObject* self, PyObject* args);
 PyObject* psutil_cpu_stats(PyObject* self, PyObject* args);
+#if (__NetBSD_Version__ - 0) >= 899004200
+PyObject *psutil_proc_cwd(PyObject *self, PyObject *args);
+#endif