add description of BB patch/checksum command

src/CommandFormats.hh

@@ -1152,10 +1152,9 @@ struct S_ConfirmUpdateQuestStatistics_AB {
 // Client will respond with a 99 command.
 
 // B2 (S->C): Execute code and/or checksum memory
-// GC v1.0 and v1.1 only.
+// GC v1.0/v1.1 and BB only.
 // Much of this command's information came from Sylverant's documentation.
 // Client will respond with a B3 command.
-// Note: BB has a handler for this, but (as of yet) I don't know what it does.
 
 struct S_ExecuteCode_GC_B2 {
   // Offsets in this command are relative to the start of the header, not the
@@ -1187,11 +1186,35 @@ struct S_ExecuteCode_Relocations_GC_B2 {
   // le_uint16_t offsets[count];
 };
 
-// B3 (C->S): Execute code and/or checksum memory result
-// GC v1.0 and v1.1 only.
+// Support exists in BB for this command, but to my knowledge it has never been
+// used. Like on GC, the client will respond with a B3 command.
 
-struct C_ExecuteCodeResult_GC_B3 {
-  le_uint32_t return_value;
+struct S_ExecuteCode_BB_B2 {
+  // If code_size == 0, no code is executed (but checksumming may still occur).
+  le_uint32_t code_size; // Size of code (following this struct) and footer
+  le_uint32_t checksum_address; // May be null if size is zero
+  le_uint32_t checksum_size;
+};
+
+struct S_ExecuteCode_Footer_BB_B2 {
+  // Relocations is a list of words (le_uint16_t) containing the number of words
+  // to skip for each relocation. The relocation pointer starts immediately
+  // after the checksum_size field in the header, and advances by the value of
+  // one word before each relocation. At each relocated doubleword, the address
+  // of the first byte of the code (after checksum_size) is added to the
+  // existing value.
+  le_uint32_t relocations_offset;
+  le_uint32_t num_relocations;
+  le_uint32_t unknown_a1[2];
+  le_uint32_t entrypoint_offset; // Relative to code base (after checksum_size)
+  le_uint32_t unknown_a2[3];
+};
+
+// B3 (C->S): Execute code and/or checksum memory result
+// GC v1.0/v1.1 and BB only.
+
+struct C_ExecuteCodeResult_GC_BB_B3 {
+  le_uint32_t return_value; // 0 if no code was run
   le_uint32_t checksum;
 };
 

src/ProxyCommands.cc

@@ -366,7 +366,7 @@ static bool process_server_88(shared_ptr<ServerState>,
   return true;
 }
 
-static bool process_server_gc_B2(shared_ptr<ServerState>,
+static bool process_server_B2(shared_ptr<ServerState>,
     ProxyServer::LinkedSession& session, uint16_t, uint32_t flag, string& data) {
   if (session.save_files) {
     string output_filename = string_printf("code.bin.%" PRId64, now());
@@ -376,7 +376,7 @@ static bool process_server_gc_B2(shared_ptr<ServerState>,
 
   if (session.function_call_return_value >= 0) {
     session.log(INFO, "Blocking function call from server");
-    C_ExecuteCodeResult_GC_B3 cmd;
+    C_ExecuteCodeResult_GC_BB_B3 cmd;
     cmd.return_value = session.function_call_return_value;
     cmd.checksum = 0;
     session.send_to_end(true, 0xB3, flag, &cmd, sizeof(cmd));
@@ -913,7 +913,7 @@ static process_command_t gc_server_handlers[0x100] = {
   /* 80 */ defh, process_server_81<SC_SimpleMail_GC_81>, defh, defh, defh, defh, defh, defh, process_server_88, defh, defh, defh, defh, defh, defh, defh,
   /* 90 */ defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, process_server_gc_9A, defh, defh, defh, defh, defh,
   /* A0 */ defh, defh, defh, defh, defh, defh, process_server_44_A6<S_OpenFile_PC_GC_44_A6>, process_server_13_A7, defh, defh, defh, defh, defh, defh, defh, defh,
-  /* B0 */ defh, defh, process_server_gc_B2, defh, defh, defh, defh, defh, process_server_gc_B8, defh, defh, defh, defh, defh, defh, defh,
+  /* B0 */ defh, defh, process_server_B2, defh, defh, defh, defh, defh, process_server_gc_B8, defh, defh, defh, defh, defh, defh, defh,
   /* C0 */ defh, defh, defh, defh, process_server_C4<S_ChoiceSearchResultEntry_GC_C4>, defh, defh, defh, defh, process_server_60_62_6C_6D_C9_CB, defh, process_server_60_62_6C_6D_C9_CB, defh, defh, defh, defh,
   /* D0 */ defh, defh, defh, defh, defh, process_server_gc_1A_D5, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,
   /* E0 */ defh, defh, defh, defh, process_server_gc_E4, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,
@@ -931,7 +931,7 @@ static process_command_t bb_server_handlers[0x100] = {
   /* 80 */ defh, defh, defh, defh, defh, defh, defh, defh, process_server_88, defh, defh, defh, defh, defh, defh, defh,
   /* 90 */ defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,
   /* A0 */ defh, defh, defh, defh, defh, defh, process_server_44_A6<S_OpenFile_BB_44_A6>, process_server_13_A7, defh, defh, defh, defh, defh, defh, defh, defh,
-  /* B0 */ defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,
+  /* B0 */ defh, defh, process_server_B2, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,
   /* C0 */ defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,
   /* D0 */ defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,
   /* E0 */ defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh, defh,