cmake: fix searching Clang RT

.github/workflows/test.yaml

@@ -23,7 +23,7 @@ jobs:
       - uses: actions/checkout@v3
 
       - name: Setup common packages
-        run: sudo apt install -y clang-14 libclang-common-14-dev
+        run: sudo apt install -y clang-15 libclang-common-15-dev
 
       - name: Setup Lua 5.1 packages
         run: sudo apt install -y lua5.1 liblua5.1-0-dev
@@ -42,7 +42,7 @@ jobs:
         if: ${{ matrix.LIBLUA == '5.4' }}
 
       - name: Running CMake
-        run: cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DENABLE_TESTING=ON -S . -B build
+        run: cmake -DCMAKE_C_COMPILER=clang-15 -DCMAKE_CXX_COMPILER=clang++-15 -DENABLE_TESTING=ON -S . -B build
 
       - name: Building
         run: cmake --build build --parallel $(nproc)

CHANGELOG.md

@@ -18,3 +18,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Disable coverage instrumentation of internal functions (#11).
+- Add missed newlines to messages.
+
+### Fixed
+
+- Fix searching Clang RT.
+- Stack overflow due to recursive traceback calls.

CMakeLists.txt

@@ -5,9 +5,11 @@ project(luzer
   VERSION "1.0.0"
 )
 
+set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+include(SetClangRTLib)
+
 find_package(Lua 5.1 REQUIRED)
 find_package(LLVM REQUIRED CONFIG)
-find_library(LIBRT rt)
 
 set(LUA_NAME "lua${LUA_VERSION_MAJOR}.${LUA_VERSION_MINOR}")
 find_program(LUA_EXECUTABLE "${LUA_NAME}")

CMakePresets.json

@@ -38,7 +38,7 @@
       "name": "default",
       "configurePreset": "default",
       "output": {"outputOnFailure": true},
-      "execution": {"noTestsAction": "error", "stopOnFailure": true}
+      "execution": {"noTestsAction": "error", "stopOnFailure": true, "timeout": 10}
     }
   ],
   "workflowPresets": [

cmake/SetClangRTLib.cmake

@@ -0,0 +1,40 @@
+# The function sets the given variable in a parent scope to a
+# value in FUZZER_NO_MAIN_LIBRARY environment variable if it
+# is set. Otherwise the value with path to a directory with
+# libclang_rt.fuzzer_no_main library is composed manually.
+# Function raises a fatal message if C compiler is not Clang.
+#
+# $ clang-15 -print-file-name=libclang_rt.fuzzer_no_main-x86_64.a
+# $ /usr/lib/llvm-15/lib/clang/15.0.7/lib/linux/libclang_rt.fuzzer_no_main-x86_64.a
+#
+# On Linux installations libFuzzer library is typically located at:
+#
+# /usr/lib/<llvm-version>/lib/clang/<clang-version>/lib/linux/libclang_rt.fuzzer_no_main-<architecture>.a
+#
+# 1. https://llvm.org/docs/LibFuzzer.html#using-libfuzzer-as-a-library
+
+function(SetFuzzerNoMainLibPath outvar)
+  if (NOT CMAKE_C_COMPILER_ID STREQUAL "Clang")
+    message(FATAL_ERROR "C compiler is not a Clang")
+  endif ()
+
+  if (CMAKE_SIZEOF_VOID_P EQUAL 4)
+    set(ARCH "i386")
+  elseif (CMAKE_SIZEOF_VOID_P EQUAL 8)
+    set(ARCH "x86_64")
+  else ()
+    message(FATAL_ERROR "Unsupported architecture.")
+  endif ()
+
+  set(LIB_FUZZER_NO_MAIN "libclang_rt.fuzzer_no_main-${ARCH}.a")
+  execute_process(COMMAND ${CMAKE_C_COMPILER} "-print-file-name=${LIB_FUZZER_NO_MAIN}"
+    RESULT_VARIABLE CMD_ERROR
+    OUTPUT_VARIABLE CMD_OUTPUT
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+  )
+  if (CMD_ERROR)
+    message(FATAL_ERROR "${CMD_ERROR}")
+  endif ()
+  set(${outvar} ${CMD_OUTPUT} PARENT_SCOPE)
+  message(STATUS "[SetClangRTLib] ${outvar} is ${CMD_OUTPUT}")
+endfunction()

luzer/CMakeLists.txt

@@ -1,17 +1,4 @@
-# Locate compiler-rt libraries.
-# Location is LLVM_LIBRARY_DIRS/clang/<version>/lib/<OS>/,
-# for example LLVM_LIBRARY_DIRS/clang/4.0.0/lib/darwin/.
-#
-# See https://llvm.org/docs/LibFuzzer.html#using-libfuzzer-as-a-library
-
-set(LLVM_BASE ${LLVM_LIBRARY_DIRS}/clang/${LLVM_PACKAGE_VERSION})
-string(TOLOWER ${CMAKE_HOST_SYSTEM_NAME} OS_NAME)
-set(LIBCLANG_RT ${LLVM_BASE}/lib/${OS_NAME}/libclang_rt.fuzzer_no_main-x86_64.a)
-if(EXISTS ${LIBCLANG_RT})
-  message(STATUS "Found libclang_rt ${LIBCLANG_RT}")
-else()
-  message(FATAL_ERROR "libclang_rt is not found")
-endif()
+SetFuzzerNoMainLibPath(FUZZER_NO_MAIN_LIBRARY)
 
 configure_file(
   ${CMAKE_CURRENT_SOURCE_DIR}/version.c
@@ -20,6 +7,7 @@ configure_file(
 )
 
 set(LUZER_SOURCES luzer.c
+                  compat.c
                   fuzzed_data_provider.cc
                   tracer.c
                   counters.c
@@ -31,9 +19,8 @@ target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE
 )
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE
 	${LUA_LIBRARIES}
-	${LIBRT}
-	${LIBCLANG_RT}
 	-fsanitize=fuzzer-no-link
+	${FUZZER_NO_MAIN_LIBRARY}
 )
 target_compile_options(${CMAKE_PROJECT_NAME} PRIVATE
 	-D_FORTIFY_SOURCE=2

luzer/compat.c

@@ -0,0 +1,151 @@
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+
+#if !defined(LUA_VERSION_NUM) || LUA_VERSION_NUM == 501
+
+static int
+countlevels(lua_State *L) {
+	lua_Debug ar;
+	int li = 1, le = 1;
+	/* Find an upper bound. */
+	while (lua_getstack(L, le, &ar))
+		{ li = le; le *= 2; }
+	/* Do a binary search. */
+	while (li < le) {
+		int m = (li + le) / 2;
+		if (lua_getstack(L, m, &ar))
+			li = m + 1;
+		else
+			le = m;
+	}
+	return le - 1;
+}
+
+static int
+findfield(lua_State *L, int objidx, int level) {
+	if (level == 0 || !lua_istable(L, -1))
+		/* Not found. */
+		return 0;
+
+	/* Start 'next' loop. */
+	lua_pushnil(L);
+	/* For each pair in table. */
+	while (lua_next(L, -2)) {
+		/* Ignore non-string keys. */
+		if (lua_type(L, -2) == LUA_TSTRING) {
+			/* Found an object? */
+			if (lua_rawequal(L, objidx, -1)) {
+				/* Remove value (but keep name). */
+				lua_pop(L, 1);
+				return 1;
+			}
+			/* Try recursively. */
+			else if (findfield(L, objidx, level - 1)) {
+				/* Remove table (but keep name). */
+				lua_remove(L, -2);
+				lua_pushliteral(L, ".");
+				/* Place '.' between the two names. */
+				lua_insert(L, -2);
+				lua_concat(L, 3);
+				return 1;
+			}
+		}
+		/* Remove value. */
+		lua_pop(L, 1);
+	}
+	/* Not found. */
+	return 0;
+}
+
+int
+lua_absindex(lua_State *L, int i) {
+	if (i < 0 && i > LUA_REGISTRYINDEX)
+		i += lua_gettop(L) + 1;
+	return i;
+}
+
+void
+lua_copy(lua_State *L, int from, int to) {
+	int abs_to = lua_absindex(L, to);
+	luaL_checkstack(L, 1, "not enough stack slots");
+	lua_pushvalue(L, from);
+	lua_replace(L, abs_to);
+}
+
+static int
+pushglobalfuncname(lua_State *L, lua_Debug *ar) {
+	int top = lua_gettop(L);
+	/* Push function. */
+	lua_getinfo(L, "f", ar);
+	lua_pushvalue(L, LUA_GLOBALSINDEX);
+	if (findfield(L, top + 1, 2)) {
+		/* Move name to proper place. */
+		lua_copy(L, -1, top + 1);
+		/* Remove pushed values. */
+		lua_pop(L, 2);
+		return 1;
+	}
+	else {
+		/* Remove function and global table. */
+		lua_settop(L, top);
+		return 0;
+	}
+}
+
+static void
+pushfuncname(lua_State *L, lua_Debug *ar) {
+	/* Is there a name? */
+	if (*ar->namewhat != '\0')
+		lua_pushfstring(L, "function " LUA_QS, ar->name);
+	else if (*ar->what == 'm')  /* Main? */
+		lua_pushliteral(L, "main chunk");
+	else if (*ar->what == 'C') {
+		if (pushglobalfuncname(L, ar)) {
+			lua_pushfstring(L, "function " LUA_QS, lua_tostring(L, -1));
+			/* Remove name. */
+			lua_remove(L, -2);
+		}
+		else
+			lua_pushliteral(L, "?");
+	}
+	else
+		lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
+}
+
+/* Size of the first part of the stack. */
+#define LEVELS1 12
+/* Size of the second part of the stack. */
+#define LEVELS2 10
+
+void
+luaL_traceback(lua_State *L, lua_State *L1,
+			   const char *msg, int level) {
+	lua_Debug ar;
+	int top = lua_gettop(L);
+	int numlevels = countlevels(L1);
+	int mark = (numlevels > LEVELS1 + LEVELS2) ? LEVELS1 : 0;
+	if (msg) lua_pushfstring(L, "%s\n", msg);
+	lua_pushliteral(L, "stack traceback:");
+	while (lua_getstack(L1, level++, &ar)) {
+		/* Too many levels? */
+		if (level == mark) {
+			/* Add a '...'. */
+			lua_pushliteral(L, "\n\t...");
+			/* And skip to last ones. */
+			level = numlevels - LEVELS2;
+		}
+		else {
+			lua_getinfo(L1, "Slnt", &ar);
+			lua_pushfstring(L, "\n\t%s:", ar.short_src);
+			if (ar.currentline > 0)
+				lua_pushfstring(L, "%d:", ar.currentline);
+				lua_pushliteral(L, " in ");
+				pushfuncname(L, &ar);
+				lua_concat(L, lua_gettop(L) - top);
+		}
+	}
+	lua_concat(L, lua_gettop(L) - top);
+}
+
+#endif

luzer/compat.h

@@ -0,0 +1,7 @@
+#ifndef LUZER_COMPAT_H_
+#define LUZER_COMPAT_H_
+
+void luaL_traceback(lua_State *L, lua_State *L1,
+					const char *msg, int level);
+
+#endif  // LUZER_COMPAT_H_