diff --git a/Makefile b/Makefile
index 56b1bb84..a8fa39dc 100644
--- a/Makefile
+++ b/Makefile
@@ -280,6 +280,12 @@ test-weak: chibi-scheme$(EXE) lib/chibi/weak$(SO)
 test-unicode: chibi-scheme$(EXE)
 	$(CHIBI) tests/unicode-tests.scm
 
+test-process: chibi-scheme$(EXE) lib/chibi/process$(SO)
+	$(CHIBI) tests/process-tests.scm
+
+test-system: chibi-scheme$(EXE) lib/chibi/system$(SO)
+	$(CHIBI) tests/system-tests.scm
+
 test-libs: chibi-scheme$(EXE)
 	$(CHIBI) tests/lib-tests.scm
 
diff --git a/lib/chibi/process.sld b/lib/chibi/process.sld
index 59049795..ec40010d 100644
--- a/lib/chibi/process.sld
+++ b/lib/chibi/process.sld
@@ -2,9 +2,10 @@
 (define-library (chibi process)
   (export exit sleep alarm fork kill execute waitpid system
           process-command-line  process-running?
-          set-signal-action! make-signal-set signal-set-contains?
+          set-signal-action! make-signal-set
+          signal-set? signal-set-contains?
           signal-set-fill! signal-set-add! signal-set-delete!
-          current-signal-mask
+          current-signal-mask current-process-id parent-process-id
           signal-mask-block! signal-mask-unblock! signal-mask-set!
           signal/hang-up    signal/interrupt   signal/quit
           signal/illegal    signal/abort       signal/fpe
@@ -23,7 +24,12 @@
            (execute cmd (cons cmd args))
            (waitpid pid 0)))))
   (cond-expand
-   (bsd #f)
+   (bsd
+    (body
+     (define (process-command-line pid)
+       (let ((res (%process-command-line pid)))
+         ;; TODO: get command-line arguments
+         (if (string? res) (list res) res)))))
    (else
     (body
      (define (process-command-line pid)
diff --git a/lib/chibi/process.stub b/lib/chibi/process.stub
index d84f9f14..fca6db84 100644
--- a/lib/chibi/process.stub
+++ b/lib/chibi/process.stub
@@ -65,7 +65,7 @@
 (define-c errno (make-signal-set "sigemptyset") ((pointer result sigset_t)))
 (define-c errno (signal-set-fill! "sigfillset") ((pointer sigset_t)))
 (define-c errno (signal-set-add! "sigaddset") ((pointer sigset_t) int))
-(define-c errno (signal-set-delete! "sigaddset") ((pointer sigset_t) int))
+(define-c errno (signal-set-delete! "sigdelset") ((pointer sigset_t) int))
 (define-c boolean (signal-set-contains? "sigismember") ((pointer sigset_t) int))
 
 (define-c errno (signal-mask-block! "sigprocmask")
@@ -124,9 +124,18 @@
 
 (define-c int (execute execvp) (string (array string)))
 
+;;> Returns the current process id.
+
+(define-c pid_t (current-process-id getpid) ())
+
+;;> Returns the parent process id.
+
+(define-c pid_t (parent-process-id getppid) ())
+
 (cond-expand
  (bsd
-  (define-c sexp (process-command-line sexp_pid_cmdline) ((value ctx sexp) int)))
+  (define-c sexp (%process-command-line sexp_pid_cmdline)
+    ((value ctx sexp) int)))
  (else #f))
 
 (c-init "sexp_init_signals(ctx, env);")
diff --git a/tests/lib-tests.scm b/tests/lib-tests.scm
index 6f3329b7..83bc8839 100644
--- a/tests/lib-tests.scm
+++ b/tests/lib-tests.scm
@@ -19,6 +19,8 @@
     (load "tests/hash-tests.scm")
     (load "tests/sort-tests.scm")
     (load "tests/io-tests.scm")
+    (load "tests/process-tests.scm")
+    (load "tests/system-tests.scm")
     (load "tests/thread-tests.scm")))
  (else #f))
 
diff --git a/tools/chibi-ffi b/tools/chibi-ffi
index b9bfd5cf..ec917425 100755
--- a/tools/chibi-ffi
+++ b/tools/chibi-ffi
@@ -439,7 +439,7 @@
          (else
           (string-append
            "sexp_unbox_fixnum(sexp_vector_ref(sexp_opcode_argn_type(self), "
-           (number->string (- i 3)) "))")))))
+           "sexp_make_fixnum("(number->string (- i 3)) ")))")))))
      (else "SEXP_OBJECT"))))
 
 (define (type-id-value type . o)