Moving nxt_stream_ident to shared memory.

This aims to avoid stream id clashes after router restart.

src/nxt_port_rpc.c

@@ -8,7 +8,7 @@
 #include <nxt_port_rpc.h>
 
 
-static nxt_atomic_t  nxt_stream_ident = 1;
+static volatile uint32_t  *nxt_stream_ident;
 
 typedef struct nxt_port_rpc_reg_s nxt_port_rpc_reg_t;
 
@@ -30,6 +30,29 @@ nxt_port_rpc_remove_from_peers(nxt_task_t *task, nxt_port_t *port,
     nxt_port_rpc_reg_t *reg);
 
 
+nxt_int_t
+nxt_port_rpc_init(void)
+{
+    void  *p;
+
+    if (nxt_stream_ident != NULL) {
+        return NXT_OK;
+    }
+
+    p = nxt_mem_mmap(NULL, sizeof(*nxt_stream_ident), PROT_READ | PROT_WRITE,
+                     MAP_ANON | MAP_SHARED, -1, 0);
+
+    if (nxt_slow_path(p == MAP_FAILED)) {
+        return NXT_ERROR;
+    }
+
+    nxt_stream_ident = p;
+    *nxt_stream_ident = 1;
+
+    return NXT_OK;
+}
+
+
 static nxt_int_t
 nxt_rpc_reg_test(nxt_lvlhsh_query_t *lhq, void *data)
 {
@@ -105,8 +128,7 @@ nxt_port_rpc_register_handler_ex(nxt_task_t *task, nxt_port_t *port,
 
     nxt_assert(port->pair[0] != -1);
 
-    stream =
+    stream = nxt_atomic_fetch_add(nxt_stream_ident, 1);
-        (uint32_t) nxt_atomic_fetch_add(&nxt_stream_ident, 1) & 0x3FFFFFFF;
 
     reg = nxt_mp_zalloc(port->mem_pool, sizeof(nxt_port_rpc_reg_t) + ex_size);
 

src/nxt_port_rpc.h

@@ -11,6 +11,8 @@
 typedef void (*nxt_port_rpc_handler_t)(nxt_task_t *task,
     nxt_port_recv_msg_t *msg, void *data);
 
+nxt_int_t nxt_port_rpc_init(void);
+
 uint32_t nxt_port_rpc_register_handler(nxt_task_t *task, nxt_port_t *port,
     nxt_port_rpc_handler_t ready_handler, nxt_port_rpc_handler_t error_handler,
     nxt_pid_t peer, void *data);

src/nxt_runtime.c

@@ -118,6 +118,10 @@ nxt_runtime_create(nxt_task_t *task)
         goto fail;
     }
 
+    if (nxt_port_rpc_init() != NXT_OK) {
+        goto fail;
+    }
+
     nxt_work_queue_add(&task->thread->engine->fast_work_queue,
                        nxt_runtime_start, task, rt, NULL);