[src/trunk]: src/libexec/httpd Cosmetic changes to Lua binding in bozohttpd.

[alnsn <alnsn%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6967a528af19
branches:  trunk
changeset: 824234:6967a528af19
user:      alnsn <alnsn%NetBSD.org@localhost>
date:      Sun May 28 22:37:36 2017 +0000

description:
Cosmetic changes to Lua binding in bozohttpd.

- Don't use negative indicies to read arguments of Lua functions.
- On error, return nil, "error string".
- Use ssize_t for return values from bozo_read() and bozo_write().
- Prefer lstring especially when if saves you from appending NUL and
  doing len + 1 which can potentially wraparound.
- Don't mix C allocations with Lua functions marked with "m" in the Lua
  manual. Those functions may throw (longjump) and leak data allocated
  by C function. In one case, I use luaL_Buffer, in the other case,
  I rearranged calls a bit.

diffstat:

 libexec/httpd/lua-bozo.c |  109 ++++++++++++++++++++++++----------------------
 1 files changed, 57 insertions(+), 52 deletions(-)

diffs (169 lines):

diff -r f0ceb2269a79 -r 6967a528af19 libexec/httpd/lua-bozo.c
--- a/libexec/httpd/lua-bozo.c  Sun May 28 21:36:18 2017 +0000
+++ b/libexec/httpd/lua-bozo.c  Sun May 28 22:37:36 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: lua-bozo.c,v 1.14 2015/12/28 07:37:59 mrg Exp $        */
+/*     $NetBSD: lua-bozo.c,v 1.15 2017/05/28 22:37:36 alnsn Exp $      */
 
 /*
  * Copyright (c) 2013 Marc Balmer <marc%msys.ch@localhost>
@@ -51,22 +51,8 @@
 
 #define FORM   "application/x-www-form-urlencoded"
 
-static int
-lua_flush(lua_State *L)
-{
-       bozohttpd_t *httpd;
-
-       lua_pushstring(L, "bozohttpd");
-       lua_gettable(L, LUA_REGISTRYINDEX);
-       httpd = lua_touserdata(L, -1);
-       lua_pop(L, 1);
-
-       bozo_flush(httpd, stdout);
-       return 0;
-}
-
-static int
-lua_print(lua_State *L)
+static bozohttpd_t *
+httpd_instance(lua_State *L)
 {
        bozohttpd_t *httpd;
 
@@ -75,56 +61,72 @@
        httpd = lua_touserdata(L, -1);
        lua_pop(L, 1);
 
-       bozo_printf(httpd, "%s\r\n", lua_tostring(L, -1));
+       return httpd;
+}
+
+static int
+lua_flush(lua_State *L)
+{
+       bozohttpd_t *httpd = httpd_instance(L);
+
+       bozo_flush(httpd, stdout);
+       return 0;
+}
+
+static int
+lua_print(lua_State *L)
+{
+       bozohttpd_t *httpd = httpd_instance(L);
+
+       bozo_printf(httpd, "%s\r\n", lua_tostring(L, 1));
        return 0;
 }
 
 static int
 lua_read(lua_State *L)
 {
-       bozohttpd_t *httpd;
-       int n, len;
+       bozohttpd_t *httpd = httpd_instance(L);
+       luaL_Buffer lbuf;
        char *data;
+       lua_Integer len;
+       ssize_t n;
 
-       lua_pushstring(L, "bozohttpd");
-       lua_gettable(L, LUA_REGISTRYINDEX);
-       httpd = lua_touserdata(L, -1);
-       lua_pop(L, 1);
+       len = luaL_checkinteger(L, 1);
+       data = luaL_buffinitsize(L, &lbuf, (size_t)len);
 
-       len = luaL_checkinteger(L, -1);
-       data = bozomalloc(httpd, len + 1);
-       n = bozo_read(httpd, STDIN_FILENO, data, len);
-       if (n >= 0) {
-               data[n] = '\0';
-               lua_pushstring(L, data);
-       } else
+       if ((n = bozo_read(httpd, STDIN_FILENO, data, len)) >= 0) {
+               luaL_pushresultsize(&lbuf, n);
+               return 1;
+       } else {
                lua_pushnil(L);
-       free(data);
-       return 1;
+               lua_pushstring(L, "bozo_read() call failed");
+               return 2;
+       }
 }
 
 static int
 lua_register_handler(lua_State *L)
 {
+       bozohttpd_t *httpd = httpd_instance(L);
        lua_state_map_t *map;
        lua_handler_t *handler;
-       bozohttpd_t *httpd;
+       const char *name;
+       int ref;
 
        lua_pushstring(L, "lua_state_map");
        lua_gettable(L, LUA_REGISTRYINDEX);
        map = lua_touserdata(L, -1);
-       lua_pushstring(L, "bozohttpd");
-       lua_gettable(L, LUA_REGISTRYINDEX);
-       httpd = lua_touserdata(L, -1);
-       lua_pop(L, 2);
+       lua_pop(L, 1);
+
+       name = luaL_checkstring(L, 1);
 
-       luaL_checkstring(L, 1);
        luaL_checktype(L, 2, LUA_TFUNCTION);
+       lua_pushvalue(L, 2);
+       ref = luaL_ref(L, LUA_REGISTRYINDEX);
 
        handler = bozomalloc(httpd, sizeof(lua_handler_t));
-
-       handler->name = bozostrdup(httpd, NULL, lua_tostring(L, 1));
-       handler->ref = luaL_ref(L, LUA_REGISTRYINDEX);
+       handler->name = bozostrdup(httpd, NULL, name);
+       handler->ref = ref;
        SIMPLEQ_INSERT_TAIL(&map->handlers, handler, h_next);
        httpd->process_lua = 1;
        return 0;
@@ -133,23 +135,26 @@
 static int
 lua_write(lua_State *L)
 {
-       bozohttpd_t *httpd;
+       bozohttpd_t *httpd = httpd_instance(L);
        const char *data;
+       size_t len;
+       ssize_t n;
 
-       lua_pushstring(L, "bozohttpd");
-       lua_gettable(L, LUA_REGISTRYINDEX);
-       httpd = lua_touserdata(L, -1);
-       lua_pop(L, 1);
-
-       data = luaL_checkstring(L, -1);
-       lua_pushinteger(L, bozo_write(httpd, STDIN_FILENO, data, strlen(data)));
-       return 1;
+       data = luaL_checklstring(L, 1, &len);
+       if ((n = bozo_write(httpd, STDIN_FILENO, data, len)) >= 0) {
+               lua_pushinteger(L, n);
+               return 1;
+       } else {
+               lua_pushnil(L);
+               lua_pushstring(L, "bozo_write() call failed");
+               return 2;
+       }
 }
 
 static int
 luaopen_httpd(lua_State *L)
 {
-       struct luaL_Reg functions[] = {
+       static struct luaL_Reg functions[] = {
                { "flush",              lua_flush },
                { "print",              lua_print },
                { "read",               lua_read },