Libunit: added a function to discern main and worker contexts.

src/nxt_unit.c

@@ -4854,6 +4854,17 @@ nxt_unit_run_shared(nxt_unit_ctx_t *ctx)
 }
 
 
+int
+nxt_unit_is_main_ctx(nxt_unit_ctx_t *ctx)
+{
+    nxt_unit_impl_t  *lib;
+
+    lib = nxt_container_of(ctx->unit, nxt_unit_impl_t, unit);
+
+    return (ctx == &lib->main_ctx.ctx);
+}
+
+
 int
 nxt_unit_process_port_msg(nxt_unit_ctx_t *ctx, nxt_unit_port_t *port)
 {

src/nxt_unit.h

@@ -210,6 +210,8 @@ int nxt_unit_run_ctx(nxt_unit_ctx_t *ctx);
 
 int nxt_unit_run_shared(nxt_unit_ctx_t *ctx);
 
+int nxt_unit_is_main_ctx(nxt_unit_ctx_t *ctx);
+
 /*
  * Receive and process one message, invoke configured callbacks.
  *