[rpcsx-os/linker] Implement module overriding with -o flag

rpcsx-os/linker.cpp

@@ -5,6 +5,7 @@
 #include "vfs.hpp"
 #include "vm.hpp"
 #include <elf.h>
+#include <map>
 #include <memory>
 #include <orbis/thread/Process.hpp>
 #include <sys/mman.h>
@@ -268,8 +269,11 @@ struct Symbol {
   std::uint64_t bindMode;
 };
 
-static std::unordered_map<std::uint64_t, std::vector<Symbol>> g_symTable;
-static std::vector<std::string> g_libraryPathList;
+static std::map<std::string, std::filesystem::path, std::less<>> g_moduleOverrideTable;
+
+void rx::linker::override(std::string originalModuleName, std::filesystem::path replacedModulePath) {
+  g_moduleOverrideTable[std::move(originalModuleName)] = std::move(replacedModulePath);
+}
 
 Ref<orbis::Module> rx::linker::loadModule(std::span<std::byte> image, orbis::Process *process) {
   Ref<orbis::Module> result{new orbis::Module{}};
@@ -755,3 +759,21 @@ Ref<orbis::Module> rx::linker::loadModuleFile(const char *path,
 
   return loadModule(image, process);
 }
+
+Ref<orbis::Module> rx::linker::loadModuleByName(std::string_view name, orbis::Process *process)  {
+  if (auto it = g_moduleOverrideTable.find(name); it != g_moduleOverrideTable.end()) {
+    return loadModuleFile(it->second.c_str(), process);
+  }
+
+  for (auto path : {"/system/common/lib/", "/system/priv/lib/"}) {
+    auto filePath = std::string(path);
+    filePath += name;
+    filePath += ".sprx";
+
+    if (auto result = rx::linker::loadModuleFile(filePath.c_str(), process)) {
+      return result;
+    }
+  }
+
+  return{};
+}

rpcsx-os/linker.hpp

@@ -3,6 +3,7 @@
 #include "orbis/module/Module.hpp"
 #include "orbis/utils/Rc.hpp"
 #include <cstddef>
+#include <filesystem>
 #include <span>
 
 namespace rx::linker {
@@ -58,6 +59,8 @@ enum OrbisElfType_t {
   kElfTypeSceDynamic = 0xfe18
 };
 
-orbis::utils::Ref<orbis::Module> loadModule(std::span<std::byte> image, orbis::Process *process);
-orbis::utils::Ref<orbis::Module> loadModuleFile(const char *path, orbis::Process *process);
+void override(std::string originalModuleName, std::filesystem::path replacedModulePath);
+orbis::Ref<orbis::Module> loadModule(std::span<std::byte> image, orbis::Process *process);
+orbis::Ref<orbis::Module> loadModuleFile(const char *path, orbis::Process *process);
+orbis::Ref<orbis::Module> loadModuleByName(std::string_view name, orbis::Process *process);
 } // namespace re::loader

rpcsx-os/main.cpp

@@ -534,6 +534,7 @@ static void usage(const char *argv0) {
   std::printf("%s [<options>...] <virtual path to elf> [args...]\n", argv0);
   std::printf("  options:\n");
   std::printf("    -m, --mount <host path> <virtual path>\n");
+  std::printf("    -o, --override <original module name> <virtual path to overriden module>\n");
   std::printf("    --trace\n");
 }
 
@@ -685,6 +686,20 @@ int main(int argc, const char *argv[]) {
       continue;
     }
 
+    if (argv[argIndex] == std::string_view("--override") ||
+        argv[argIndex] == std::string_view("-o")) {
+      if (argc <= argIndex + 2) {
+        usage(argv[0]);
+        return 1;
+      }
+
+      rx::linker::override(argv[argIndex + 1], argv[argIndex + 2]);
+
+      argIndex += 3;
+      continue;
+    }
+
+
     break;
   }
 

rpcsx-os/ops.cpp

@@ -468,23 +468,9 @@ SysResult processNeeded(Thread *thread) {
         continue;
       }
 
-      hasLoadedNeeded = true;
+      auto neededModule = rx::linker::loadModuleByName(needed, proc);
 
-      std::printf("loading needed: %s\n", needed.c_str());
-      bool isLoaded = false;
-      for (auto path : {"/system/common/lib/", "/system/priv/lib/"}) {
-        auto loadedNeeded = rx::linker::loadModuleFile(
-            (std::string(path) + needed + ".sprx").c_str(), proc);
-
-        if (loadedNeeded == nullptr) {
-          continue;
-        }
-
-        isLoaded = true;
-        break;
-      }
-
-      if (!isLoaded) {
+      if (neededModule == nullptr) {
         std::printf("Needed '%s' not found\n", needed.c_str());
         return ErrorCode::NOENT;
       }