diff --git a/psutil/_psbsd.py b/psutil/_psbsd.py
index d53eb0427..0568e3a85 100644
--- a/psutil/_psbsd.py
+++ b/psutil/_psbsd.py
@@ -51,7 +51,7 @@
         cext.SWAIT: _common.STATUS_WAITING,
         cext.SLOCK: _common.STATUS_LOCKED,
     }
-elif OPENBSD or NETBSD:
+elif OPENBSD:
     PROC_STATUSES = {
         cext.SIDL: _common.STATUS_IDLE,
         cext.SSLEEP: _common.STATUS_SLEEPING,
@@ -76,12 +76,11 @@
 elif NETBSD:
     PROC_STATUSES = {
         cext.SIDL: _common.STATUS_IDLE,
-        cext.SACTIVE: _common.STATUS_RUNNING,
-        cext.SDYING: _common.STATUS_ZOMBIE,
+        cext.SSLEEP: _common.STATUS_SLEEPING,
         cext.SSTOP: _common.STATUS_STOPPED,
         cext.SZOMB: _common.STATUS_ZOMBIE,
-        cext.SDEAD: _common.STATUS_DEAD,
-        cext.SSUSPENDED: _common.STATUS_SUSPENDED,  # unique to NetBSD
+        cext.SRUN: _common.STATUS_WAKING,
+        cext.SONPROC: _common.STATUS_RUNNING,
     }
 
 TCP_STATUSES = {
@@ -669,6 +668,10 @@ def cmdline(self):
         else:
             return cext.proc_cmdline(self.pid)
 
+    @wrap_exceptions
+    def environ(self):
+        return cext.proc_environ(self.pid)
+
     @wrap_exceptions
     def terminal(self):
         tty_nr = self.oneshot()[kinfo_proc_map['ttynr']]
diff --git a/psutil/_psutil_bsd.c b/psutil/_psutil_bsd.c
index 953fcd083..c4450d7df 100644
--- a/psutil/_psutil_bsd.c
+++ b/psutil/_psutil_bsd.c
@@ -57,6 +57,7 @@
 #include <net/route.h>
 #include <netinet/in.h>   // process open files/connections
 #include <sys/un.h>
+#include <kvm.h>
 
 #include "_psutil_common.h"
 #include "_psutil_posix.h"
@@ -391,6 +392,145 @@ psutil_proc_cmdline(PyObject *self, PyObject *args) {
 }
 
 
+/*
+ * Return process environment as a Python dictionary
+ */
+PyObject *
+psutil_proc_environ(PyObject *self, PyObject *args) {
+    int i, cnt = -1;
+    long pid;
+    char *s, **envs, errbuf[_POSIX2_LINE_MAX];
+    PyObject *py_value=NULL, *py_retdict=NULL;
+    kvm_t *kd;
+#ifdef PSUTIL_NETBSD
+    struct kinfo_proc2 *p;
+#else
+    struct kinfo_proc *p;
+#endif
+
+    if (!PyArg_ParseTuple(args, "l", &pid))
+        return NULL;
+
+#if defined(PSUTIL_FREEBSD)
+    kd = kvm_openfiles(NULL, "/dev/null", NULL, 0, errbuf);
+#else
+    kd = kvm_openfiles(NULL, NULL, NULL, KVM_NO_FILES, errbuf);
+#endif
+    if (!kd) {
+        convert_kvm_err("kvm_openfiles", errbuf);
+        return NULL;
+    }
+
+    py_retdict = PyDict_New();
+    if (!py_retdict)
+        goto error;
+
+#if defined(PSUTIL_FREEBSD)
+    p = kvm_getprocs(kd, KERN_PROC_PID, pid, &cnt);
+#elif defined(PSUTIL_OPENBSD)
+    p = kvm_getprocs(kd, KERN_PROC_PID, pid, sizeof(*p), &cnt);
+#elif defined(PSUTIL_NETBSD)
+    p = kvm_getproc2(kd, KERN_PROC_PID, pid, sizeof(*p), &cnt);
+#endif
+    if (!p) {
+        NoSuchProcess("kvm_getprocs");
+        goto error;
+    }
+    if (cnt <= 0) {
+        NoSuchProcess(cnt < 0 ? kvm_geterr(kd) : "kvm_getprocs: cnt==0");
+        goto error;
+    }
+
+    // On *BSD kernels there are a few kernel-only system processes without an
+    // environment (See e.g. "procstat -e 0 | 1 | 2 ..." on FreeBSD.)
+    //
+    // Some system process have no stats attached at all
+    // (they are marked with P_SYSTEM.)
+    //
+    // On FreeBSD, it's possible that the process is swapped or paged out,
+    // then there no access to the environ stored in the process' user area.
+    //
+    // On NetBSD, we cannot call kvm_getenvv2() for a zombie process.
+    //
+    // To make unittest suite happy, return an empty environment.
+    //
+#if defined(PSUTIL_FREEBSD)
+#if (defined(__FreeBSD_version) && __FreeBSD_version >= 700000)
+    if (!((p)->ki_flag & P_INMEM) || ((p)->ki_flag & P_SYSTEM)) {
+#else
+    if ((p)->ki_flag & P_SYSTEM) {
+#endif
+#elif defined(PSUTIL_NETBSD)
+    if ((p)->p_stat == SZOMB) {
+#elif defined(PSUTIL_OPENBSD)
+    if ((p)->p_flag & P_SYSTEM) {
+#endif
+        kvm_close(kd);
+        return py_retdict;
+    }
+
+#if defined(PSUTIL_NETBSD)
+    envs = kvm_getenvv2(kd, p, 0);
+#else
+    envs = kvm_getenvv(kd, p, 0);
+#endif
+    if (!envs) {
+        // Map to "psutil" general high-level exceptions
+        switch (errno) {
+            case 0:
+                // Process has cleared it's environment, return empty one
+                kvm_close(kd);
+                return py_retdict;
+            case EPERM:
+                AccessDenied("kvm_getenvv");
+                break;
+            case ESRCH:
+                NoSuchProcess("kvm_getenvv");
+                break;
+#if defined(PSUTIL_FREEBSD)
+            case ENOMEM:
+                // Unfortunately, under FreeBSD kvm_getenvv() returns
+                // failure for certain processes ( e.g. try
+                // "sudo procstat -e <pid of your XOrg server>".)
+                // Map the error condition to 'AccessDenied'.
+                sprintf(errbuf,
+                        "kvm_getenvv(pid=%ld, ki_uid=%d): errno=ENOMEM",
+                        pid, p->ki_uid);
+                AccessDenied(errbuf);
+                break;
+#endif
+            default:
+                sprintf(errbuf, "kvm_getenvv(pid=%ld)", pid);
+                PyErr_SetFromOSErrnoWithSyscall(errbuf);
+                break;
+        }
+        goto error;
+    }
+
+    for (i = 0; envs[i] != NULL; i++) {
+        s = strchr(envs[i], '=');
+        if (!s)
+            continue;
+        *s++ = 0;
+        py_value = PyUnicode_DecodeFSDefault(s);
+        if (!py_value)
+            goto error;
+        if (PyDict_SetItemString(py_retdict, envs[i], py_value)) {
+            goto error;
+        }
+        Py_DECREF(py_value);
+    }
+
+    kvm_close(kd);
+    return py_retdict;
+
+error:
+    Py_XDECREF(py_value);
+    Py_XDECREF(py_retdict);
+    kvm_close(kd);
+    return NULL;
+}
+
 /*
  * Return the number of logical CPUs in the system.
  * XXX this could be shared with macOS
@@ -617,8 +757,10 @@ psutil_disk_partitions(PyObject *self, PyObject *args) {
             strlcat(opts, ",softdep", sizeof(opts));
         if (flags & MNT_NOSYMFOLLOW)
             strlcat(opts, ",nosymfollow", sizeof(opts));
+#ifdef MNT_GJOURNAL
         if (flags & MNT_GJOURNAL)
             strlcat(opts, ",gjournal", sizeof(opts));
+#endif
         if (flags & MNT_MULTILABEL)
             strlcat(opts, ",multilabel", sizeof(opts));
         if (flags & MNT_ACLS)
@@ -627,8 +769,10 @@ psutil_disk_partitions(PyObject *self, PyObject *args) {
             strlcat(opts, ",noclusterr", sizeof(opts));
         if (flags & MNT_NOCLUSTERW)
             strlcat(opts, ",noclusterw", sizeof(opts));
+#ifdef MNT_NFS4ACLS
         if (flags & MNT_NFS4ACLS)
             strlcat(opts, ",nfs4acls", sizeof(opts));
+#endif
 #elif PSUTIL_NETBSD
         if (flags & MNT_NODEV)
             strlcat(opts, ",nodev", sizeof(opts));
@@ -831,7 +975,7 @@ psutil_users(PyObject *self, PyObject *args) {
             py_tty,             // tty
             py_hostname,        // hostname
             (float)ut.ut_time,  // start time
-#ifdef PSUTIL_OPENBSD
+#if defined(PSUTIL_OPENBSD) || (defined(__FreeBSD_version) && __FreeBSD_version < 900000)
             -1                  // process id (set to None later)
 #else
             ut.ut_pid           // TODO: use PyLong_FromPid
@@ -956,6 +1100,8 @@ static PyMethodDef mod_methods[] = {
     {"cpu_count_phys", psutil_cpu_count_phys, METH_VARARGS,
      "Return an XML string to determine the number physical CPUs."},
 #endif
+    {"proc_environ", psutil_proc_environ, METH_VARARGS,
+     "Return process environment"},
 
     // --- system-related functions
 
@@ -1060,7 +1206,9 @@ static PyMethodDef mod_methods[] = {
     if (PyModule_AddIntConstant(mod, "SSLEEP", LSSLEEP)) INITERR;
     if (PyModule_AddIntConstant(mod, "SSTOP", LSSTOP)) INITERR;
     if (PyModule_AddIntConstant(mod, "SZOMB", LSZOMB)) INITERR;
+#if __NetBSD_Version__ < 500000000
     if (PyModule_AddIntConstant(mod, "SDEAD", LSDEAD)) INITERR;
+#endif
     if (PyModule_AddIntConstant(mod, "SONPROC", LSONPROC)) INITERR;
     // unique to NetBSD
     if (PyModule_AddIntConstant(mod, "SSUSPENDED", LSSUSPENDED)) INITERR;
diff --git a/psutil/_psutil_common.c b/psutil/_psutil_common.c
index 7a87c3c19..f821aba38 100644
--- a/psutil/_psutil_common.c
+++ b/psutil/_psutil_common.c
@@ -167,6 +167,26 @@ psutil_setup(void) {
 }
 
 
+// ============================================================================
+// Utility functions (BSD)
+// ============================================================================
+
+#if defined(PSUTIL_FREEBSD) || defined(PSUTIL_OPENBSD) || defined(PSUTIL_NETBSD)
+void
+convert_kvm_err(const char *syscall, char *errbuf) {
+    char fullmsg[8192];
+
+    sprintf(fullmsg, "(originated from %s: %s)", syscall, errbuf);
+    if (strstr(errbuf, "Permission denied") != NULL)
+        AccessDenied(fullmsg);
+    else if (strstr(errbuf, "Operation not permitted") != NULL)
+        AccessDenied(fullmsg);
+    else
+        PyErr_Format(PyExc_RuntimeError, fullmsg);
+}
+#endif
+
+
 // ====================================================================
 // --- Windows
 // ====================================================================
diff --git a/psutil/_psutil_common.h b/psutil/_psutil_common.h
index 2408c9f63..3162772eb 100644
--- a/psutil/_psutil_common.h
+++ b/psutil/_psutil_common.h
@@ -104,6 +104,12 @@ PyObject* psutil_set_testing(PyObject *self, PyObject *args);
 void psutil_debug(const char* format, ...);
 int psutil_setup(void);
 
+// ====================================================================
+// --- BSD
+// ====================================================================
+
+void convert_kvm_err(const char *syscall, char *errbuf);
+
 // ====================================================================
 // --- Windows
 // ====================================================================
diff --git a/psutil/arch/freebsd/specific.c b/psutil/arch/freebsd/specific.c
index 3f37a08e2..c78326479 100644
--- a/psutil/arch/freebsd/specific.c
+++ b/psutil/arch/freebsd/specific.c
@@ -517,7 +517,7 @@ psutil_swap_mem(PyObject *self, PyObject *args) {
 }
 
 
-#if defined(__FreeBSD_version) && __FreeBSD_version >= 800000
+#if defined(__FreeBSD_version) && __FreeBSD_version >= 701000
 PyObject *
 psutil_proc_cwd(PyObject *self, PyObject *args) {
     pid_t pid;
@@ -795,9 +795,11 @@ psutil_proc_memory_maps(PyObject *self, PyObject *args) {
                 case KVME_TYPE_DEAD:
                     path = "[dead]";
                     break;
+#ifdef KVME_TYPE_SG
                 case KVME_TYPE_SG:
                     path = "[sg]";
                     break;
+#endif
                 case KVME_TYPE_UNKNOWN:
                     path = "[unknown]";
                     break;
diff --git a/psutil/arch/freebsd/sys_socks.c b/psutil/arch/freebsd/sys_socks.c
index ab61f393b..9f7cf8d55 100644
--- a/psutil/arch/freebsd/sys_socks.c
+++ b/psutil/arch/freebsd/sys_socks.c
@@ -16,6 +16,9 @@
 #include <sys/un.h>
 #include <sys/unpcb.h>
 #include <sys/sysctl.h>
+#if defined(__FreeBSD_version) && __FreeBSD_version < 800000
+#include <netinet/in_systm.h>
+#endif
 #include <netinet/in.h>   // for xinpcb struct
 #include <netinet/ip.h>
 #include <netinet/in_pcb.h>
@@ -30,7 +33,7 @@ static int psutil_nxfiles;
 
 
 int
-psutil_populate_xfiles() {
+psutil_populate_xfiles(void) {
     size_t len;
 
     if ((psutil_xfiles = malloc(len = sizeof *psutil_xfiles)) == NULL) {
diff --git a/psutil/arch/openbsd/specific.c b/psutil/arch/openbsd/specific.c
index d97a8f9b9..aa4568f59 100644
--- a/psutil/arch/openbsd/specific.c
+++ b/psutil/arch/openbsd/specific.c
@@ -47,20 +47,6 @@
 // ============================================================================
 
 
-static void
-convert_kvm_err(const char *syscall, char *errbuf) {
-    char fullmsg[8192];
-
-    sprintf(fullmsg, "(originated from %s: %s)", syscall, errbuf);
-    if (strstr(errbuf, "Permission denied") != NULL)
-        AccessDenied(fullmsg);
-    else if (strstr(errbuf, "Operation not permitted") != NULL)
-        AccessDenied(fullmsg);
-    else
-        PyErr_Format(PyExc_RuntimeError, fullmsg);
-}
-
-
 int
 psutil_kinfo_proc(pid_t pid, struct kinfo_proc *proc) {
     // Fills a kinfo_proc struct based on process pid.
diff --git a/psutil/tests/test_contracts.py b/psutil/tests/test_contracts.py
index 51bbb9f09..2d9e5917e 100755
--- a/psutil/tests/test_contracts.py
+++ b/psutil/tests/test_contracts.py
@@ -137,7 +137,8 @@ class TestAvailProcessAPIs(PsutilTestCase):
 
     def test_environ(self):
         self.assertEqual(hasattr(psutil.Process, "environ"),
-                         LINUX or MACOS or WINDOWS or AIX or SUNOS)
+                         LINUX or MACOS or WINDOWS or AIX or SUNOS or
+                         FREEBSD or OPENBSD or NETBSD)
 
     def test_uids(self):
         self.assertEqual(hasattr(psutil.Process, "uids"), POSIX)
diff --git a/psutil/tests/test_process.py b/psutil/tests/test_process.py
index e3394799c..8b5e5c56d 100755
--- a/psutil/tests/test_process.py
+++ b/psutil/tests/test_process.py
@@ -298,7 +298,7 @@ def test_create_time(self):
     @unittest.skipIf(TRAVIS or CIRRUS, 'not reliable on TRAVIS/CIRRUS')
     def test_terminal(self):
         terminal = psutil.Process().terminal()
-        if sys.stdout.isatty():
+        if sys.stdin.isatty():
             tty = os.path.realpath(sh('tty'))
             self.assertEqual(terminal, tty)
         else: