From eb39277d4a5bababbd7169af2106b396125f1c65 Mon Sep 17 00:00:00 2001
From: Amaury Pouly <amaury.pouly@gmail.com>
Date: Fri, 23 Feb 2018 22:13:19 +1100
Subject: [PATCH] hwstub: allow minor version mismatch in net layer

Change-Id: I81a75bd7b9f3fd1a56e5bea521966c1847adfec7
---
 utils/hwstub/include/hwstub_net.hpp |  2 ++
 utils/hwstub/lib/hwstub_net.cpp     | 33 ++++++++++++++++++++++-------
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/utils/hwstub/include/hwstub_net.hpp b/utils/hwstub/include/hwstub_net.hpp
index 72d73e83e5..f6992b5348 100644
--- a/utils/hwstub/include/hwstub_net.hpp
+++ b/utils/hwstub/include/hwstub_net.hpp
@@ -112,6 +112,7 @@ protected:
     virtual void destroy_device_list(void *ptr);
     virtual error create_device(ctx_dev_t dev, std::shared_ptr<hwstub::device>& hwdev);
     virtual bool match_device(ctx_dev_t dev, std::shared_ptr<hwstub::device> hwdev);
+    static inline int hwstub_ver(int major, int minor) { return major * 100 + minor; }
 
     enum class state
     {
@@ -122,6 +123,7 @@ protected:
 
     state m_state; /* client state */
     error m_error; /* error state for DEAD */
+    int m_ver; /* Server revision (uses hwstub_ver()) */
 };
 
 /** Socket based net context
diff --git a/utils/hwstub/lib/hwstub_net.cpp b/utils/hwstub/lib/hwstub_net.cpp
index 6f828f81ec..851723f37d 100644
--- a/utils/hwstub/lib/hwstub_net.cpp
+++ b/utils/hwstub/lib/hwstub_net.cpp
@@ -437,14 +437,25 @@ void context::delayed_init()
         return;
     }
     /* check the server is running the same version */
-    debug() << "[net::ctx] <-- HELLO " << ((args[0] & 0xff00) >> 8) << "." << (args[0] & 0xff) << "";
-    if(args[0] != (HWSTUB_VERSION_MAJOR << 8 | HWSTUB_VERSION_MINOR))
+    int serv_maj = (args[0] >> 8) & 0xff;
+    int serv_min = args[0] & 0xff;
+    debug() << "[net::ctx] <-- HELLO " << serv_maj << "." << serv_min << "";
+
+    m_ver = hwstub_ver(serv_maj, serv_min);
+    /* Major mismatch -> error */
+    if(serv_maj != HWSTUB_VERSION_MAJOR)
     {
-        debug() << " (mismatch)\n";
+        debug() << " (major version mismatch)\n";
         m_state = state::DEAD;
         m_error = error::SERVER_MISMATCH;
     }
-    debug() << " (good)\n";
+    else
+        debug() << " (good)\n";
+    /* Minor mismatch -> warning */
+    if(serv_min < HWSTUB_VERSION_MINOR)
+        debug() << "[net::ctx] Some operations might not be supported by the server.\n";
+    else if(serv_min > HWSTUB_VERSION_MINOR)
+        debug() << "[net::ctx] Some operations might not be supported by this client.\n";
     /* good, we can now send commands */
     m_state = state::IDLE;
 }
@@ -994,16 +1005,22 @@ error server::handle_cmd(client_state *state, uint32_t cmd, uint32_t args[HWSTUB
     /* HELLO */
     if(cmd == HWSERVER_HELLO)
     {
-        debug() << "[net::srv::cmd] --> HELLO " << ((args[0] & 0xff00) >> 8)
-            << "." << (args[0] & 0xff);
-        if(args[0] != (HWSTUB_VERSION_MAJOR << 8 | HWSTUB_VERSION_MINOR))
+        int cli_maj = (args[0] >> 8) & 0xff;
+        int cli_min = args[0] & 0xff;
+        debug() << "[net::srv::cmd] --> HELLO " << cli_maj << "." << cli_min;
+        if(cli_maj != HWSTUB_VERSION_MAJOR)
         {
-            debug() << " (mismatch)\n";
+            debug() << " (major version mismatch)\n";
             return error::ERROR;
         }
         debug() << " (good)\n";
         debug() << "[net::srv::cmd] <-- HELLO " << HWSTUB_VERSION_MAJOR << "."
             << HWSTUB_VERSION_MINOR << "\n";
+        /* Minor mismatch -> warning */
+        if(cli_min < HWSTUB_VERSION_MINOR)
+            debug() << "[net::ctx] Some operations might not be supported by the client.\n";
+        else if(cli_min > HWSTUB_VERSION_MINOR)
+            debug() << "[net::ctx] Some operations might not be supported by this server.\n";
         /* send HELLO with our version */
         args[0] = HWSTUB_VERSION_MAJOR << 8 | HWSTUB_VERSION_MINOR;
         return error::SUCCESS;