diff --git a/lib/chibi/signal.c b/lib/chibi/signal.c
new file mode 100644
index 00000000..6def22ef
--- /dev/null
+++ b/lib/chibi/signal.c
@@ -0,0 +1,59 @@
+
+#define SEXP_MAX_SIGNUM 32
+
+static sexp sexp_signal_contexts[SEXP_MAX_SIGNUM];
+
+static void sexp_call_sigaction (int signum, siginfo_t *info, void *uctx) {
+  sexp ctx, sigctx, handler;
+  sexp_gc_var1(args);
+  ctx = sexp_signal_contexts[signum];
+  if (ctx) {
+    handler = sexp_vector_ref(sexp_global(ctx, SEXP_G_SIGNAL_HANDLERS),
+                              sexp_make_fixnum(signum));
+    if (sexp_truep(handler)) {
+      sigctx = sexp_make_child_context(ctx, NULL);
+      sexp_gc_preserve1(sigctx, args);
+      args = sexp_cons(sigctx, SEXP_FALSE, SEXP_NULL);
+      sexp_car(args)
+        = sexp_make_cpointer(sigctx, sexp_siginfo_type_id, info, SEXP_FALSE, 0);
+      args = sexp_cons(sigctx, SEXP_FALSE, args);
+      sexp_car(args) = sexp_make_fixnum(signum);
+      sexp_apply(sigctx, handler, args);
+      sexp_gc_release1(sigctx);
+    }
+  }
+}
+
+static struct sigaction call_sigaction = {
+  .sa_sigaction = sexp_call_sigaction,
+  .sa_flags = SA_SIGINFO | SA_NODEFER
+};
+
+static struct sigaction call_sigdefault = {.sa_handler = SIG_DFL};
+static struct sigaction call_sigignore = {.sa_handler = SIG_IGN};
+
+static sexp sexp_set_signal_action (sexp ctx, sexp signum, sexp newaction) {
+  int res;
+  sexp oldaction;
+  if (! (sexp_fixnump(signum) && sexp_unbox_fixnum(signum) > 0
+         && sexp_unbox_fixnum(signum) < SEXP_MAX_SIGNUM))
+    return sexp_type_exception(ctx, "not a valid signal number", signum);
+  if (! (sexp_procedurep(newaction) || sexp_opcodep(newaction)
+         || sexp_booleanp(newaction)))
+    return sexp_type_exception(ctx, "not a procedure", newaction);
+  if (! sexp_vectorp(sexp_global(ctx, SEXP_G_SIGNAL_HANDLERS)))
+    sexp_global(ctx, SEXP_G_SIGNAL_HANDLERS)
+      = sexp_make_vector(ctx, sexp_make_fixnum(SEXP_MAX_SIGNUM), SEXP_FALSE);
+  oldaction = sexp_vector_ref(sexp_global(ctx, SEXP_G_SIGNAL_HANDLERS), signum);
+  res = sigaction(sexp_unbox_fixnum(signum),
+                  (sexp_booleanp(newaction) ?
+                   (sexp_truep(newaction) ? &call_sigdefault : &call_sigignore)
+                   : &call_sigaction),
+                  NULL);
+  if (res)
+    return sexp_user_exception(ctx, SEXP_FALSE, "couldn't set signal", signum);
+  sexp_vector_set(sexp_global(ctx, SEXP_G_SIGNAL_HANDLERS), signum, newaction);
+  sexp_signal_contexts[sexp_unbox_fixnum(signum)] = ctx;
+  return oldaction;
+}
+