Handle formatted string in log

1 files changed, 24 insertions, 9 deletions

diff --git a/src/lua/log.c b/src/lua/log.c
index d02775c..4bf4e16 100644
--- a/src/lua/log.c
+++ b/src/lua/log.c
@@ -4,8 +4,20 @@
 #include "api.h"
 #include "../any_log.h"
 
+static lua_CFunction lua_log_stringformat = NULL;
+
 static int lua_log_format(lua_State *state, any_log_level_t level) {
-    const char *value = luaL_checkstring(state, 1);
+
+    // Use string.format to print safely
+    //
+    int n_args = lua_gettop(state);
+    lua_pushcfunction(state, lua_log_stringformat);
+
+    for (int i = 1; i <= n_args; ++i)
+        lua_pushvalue(state, i);
+
+    lua_call(state, n_args, 1);
+    const char *message = lua_tostring(state, -1);
 
     lua_getglobal(state, "debug");
     lua_getfield(state, -1, "getinfo");
@@ -15,8 +27,8 @@ static int lua_log_format(lua_State *state, any_log_level_t level) {
     // S: source, l: currentline, n: name
     lua_pushstring(state, "Sln");
 
-    const char *source = "x", *func = "y";
-    char buffer[4096] = { 0 };
+    const char *source = "?", *func = "?";
+    char buffer[4096];
 
     if (lua_pcall(state, 2, 1, 0) == LUA_OK) {
 
@@ -33,18 +45,15 @@ static int lua_log_format(lua_State *state, any_log_level_t level) {
             snprintf(buffer, sizeof(buffer), "lua %s:%d", shortsrc, line);
         }
 
-        source = buffer;
-
         lua_getfield(state, -3, "name");
         const char *name = lua_tostring(state, -1);
 
-        func = name == NULL
-             ? "..."
-             : name;
+        source = buffer;
+        func = name ? name :  "...";
     }
 
     lua_pop(state, 3);
-    any_log_format(level, source, func, "%s", value);
+    any_log_format(level, source, func, "%s", message);
     return 0;
 }
 
@@ -92,6 +101,12 @@ int lua_log_library(lua_State *state)
         { "trace", lua_log_trace },
         { NULL, NULL },
     };
+
+    lua_getglobal(state, "string");
+    lua_getfield(state, -1, "format");
+    lua_log_stringformat = lua_tocfunction(state, -1);
+    lua_pop(state, 2);
+
     luaL_newlib(state, library);
     return 1;
 }