add load exec

Co-authored-by: thenotsoquietninja44-collab <thenotsoquietninja44@gmail.com>

src/loader/loadExec.cpp

@@ -0,0 +1,63 @@
+#include "emulator.h"
+
+#include "common/file.h"
+#include "common/logging/log.h"
+#include "kernel/fileSystem.h"
+#include "libs/errno.h"
+
+#include <cerrno>
+#include <cstring>
+#include <fstream>
+#include <string_view>
+#include <vector>
+
+#if KYTY_PLATFORM == KYTY_PLATFORM_LINUX
+#include <linux/close_range.h>
+#include <unistd.h>
+#endif
+
+namespace Emulator {
+
+int LoadExec(const char* path, const char* const argv[]) {
+	using namespace Libs::SystemService;
+	if (path == nullptr || !std::string_view(path).starts_with("/app0/") ||
+	    !Common::File::IsFileExisting(Libs::LibKernel::FileSystem::GetRealFilename(path))) {
+		return SYSTEM_SERVICE_ERROR_PARAMETER;
+	}
+#if KYTY_PLATFORM == KYTY_PLATFORM_LINUX
+	std::ifstream command("/proc/self/cmdline", std::ios::binary);
+	std::vector<std::string> arguments;
+	for (std::string argument; std::getline(command, argument, '\0') && argument != "--guest-exec";) {
+		arguments.push_back(std::move(argument));
+	}
+	if (arguments.empty()) {
+		return SYSTEM_SERVICE_ERROR_INTERNAL;
+	}
+	arguments.insert(arguments.end(), {"--guest-exec", path});
+	size_t bytes = 0;
+	for (size_t i = 0; argv != nullptr && argv[i] != nullptr; ++i) {
+		const auto size = strnlen(argv[i], 4096 - bytes) + 1;
+		if (size > 4096 - bytes) {
+			return SYSTEM_SERVICE_ERROR_PARAMETER;
+		}
+		bytes += size;
+		arguments.emplace_back(argv[i]);
+	}
+	std::vector<char*> host_argv;
+	for (auto& argument: arguments) {
+		host_argv.push_back(argument.data());
+	}
+	host_argv.push_back(nullptr);
+	LOGF("LoadExec: %s\n", path);
+	Log::Flush();
+	if (close_range(3, ~0u, CLOSE_RANGE_UNSHARE | CLOSE_RANGE_CLOEXEC) == 0) {
+		execvp(host_argv[0], host_argv.data());
+	}
+	LOGF("LoadExec failed: %s\n", std::strerror(errno));
+	return SYSTEM_SERVICE_ERROR_INTERNAL;
+#else
+	return SYSTEM_SERVICE_ERROR_UNAVAILABLE;
+#endif
+}
+
+} // namespace Emulator

src/loader/runtimeLinker.cpp

@@ -25,6 +25,7 @@
 
 #include <algorithm>
 #include <atomic>
+#include <cstddef>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
@@ -88,16 +89,6 @@ ThreadLocalStorage::~ThreadLocalStorage() {
 	}
 }
 
-#pragma pack(1)
-
-struct EntryParams {
-	int         argc;
-	uint32_t    pad;
-	const char* argv[3];
-};
-
-#pragma pack()
-
 using atexit_func_t = KYTY_SYSV_ABI void (*)();
 using entry_func_t  = KYTY_SYSV_ABI void (*)(EntryParams* params, atexit_func_t atexit_func);
 using module_ini_fini_func_t = KYTY_SYSV_ABI int (*)(size_t args, const void* argp,
@@ -1283,11 +1274,16 @@ void RuntimeLinker::Execute(const std::filesystem::path& game_patch) {
 	LOGF_COLOR(Log::Color::BrightYellow, "---\n--- Execute: %s\n---\n", "Main");
 
 	if (auto entry = GetEntry(); entry != 0) {
+		const auto& arguments = Config::GetGuestArguments();
+		const auto params_size = offsetof(EntryParams, argv) +
+		                         (arguments.size() + 2) * sizeof(const char*);
 		auto* params = reinterpret_cast<EntryParams*>(
-		    (reinterpret_cast<uintptr_t>(main_stack_top) - 0x100u) & ~static_cast<uintptr_t>(0x0f));
-		std::memset(params, 0, sizeof(EntryParams));
-		params->argc    = 1;
-		params->argv[0] = "KytyEmu";
+		    (reinterpret_cast<uintptr_t>(main_stack_top) - params_size - 0x100u) &
+		    ~static_cast<uintptr_t>(0x0f));
+		std::memset(params, 0, params_size);
+		for (const auto& argument: arguments) {
+			params->argv[params->argc++] = argument.c_str();
+		}
 
 		LOGF("stack_addr = %" PRIx64 "\n", reinterpret_cast<uint64_t>(params));
 

src/loader/runtimeLinker.h

@@ -14,6 +14,12 @@
 
 namespace Loader {
 
+struct EntryParams {
+	int         argc;
+	uint32_t    pad;
+	const char* argv[1];
+};
+
 class Elf64;
 struct Elf64_Sym;
 struct Elf64_Rela;