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util-src/windows.c @ 11665:148075532021
net.server_epoll: Prevent stack overflow of opportunistic writes
net.http.files serving a big enough file on a fast enough connection
with opportunistic_writes enabled could trigger a stack overflow through
repeatedly serving more data that immediately gets sent, draining the
buffer and triggering more data to be sent. This also blocked the server
on a single task until completion or an error.
This change prevents nested opportunistic writes, which should prevent
the stack overflow, at the cost of reduced download speed, but this is
unlikely to be noticeable outside of Gbit networks. Speed at the cost of
blocking other processing is not worth it, especially with the risk of
stack overflow.
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sun, 11 Jul 2021 09:39:21 +0200 |
parent | 10921:6eb5d2bb11af |
child | 12575:1f6f05a98fcd |
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/* Prosody IM -- Copyright (C) 2008-2010 Matthew Wild -- Copyright (C) 2008-2010 Waqas Hussain -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- */ /* * windows.c * Windows support functions for Lua */ #include <stdio.h> #include <windows.h> #include <windns.h> #include "lua.h" #include "lauxlib.h" #if (LUA_VERSION_NUM == 501) #define luaL_setfuncs(L, R, N) luaL_register(L, NULL, R) #endif #if (LUA_VERSION_NUM < 504) #define luaL_pushfail lua_pushnil #endif static int Lget_nameservers(lua_State *L) { char stack_buffer[1024]; // stack allocated buffer IP4_ARRAY *ips = (IP4_ARRAY *) stack_buffer; DWORD len = sizeof(stack_buffer); DNS_STATUS status; status = DnsQueryConfig(DnsConfigDnsServerList, FALSE, NULL, NULL, ips, &len); if(status == 0) { DWORD i; lua_createtable(L, ips->AddrCount, 0); for(i = 0; i < ips->AddrCount; i++) { DWORD ip = ips->AddrArray[i]; char ip_str[16] = ""; sprintf_s(ip_str, sizeof(ip_str), "%d.%d.%d.%d", (ip >> 0) & 255, (ip >> 8) & 255, (ip >> 16) & 255, (ip >> 24) & 255); lua_pushstring(L, ip_str); lua_rawseti(L, -2, i + 1); } return 1; } else { luaL_pushfail(L); lua_pushfstring(L, "DnsQueryConfig returned %d", status); return 2; } } static int lerror(lua_State *L, char *string) { luaL_pushfail(L); lua_pushfstring(L, "%s: %d", string, GetLastError()); return 2; } static int Lget_consolecolor(lua_State *L) { HWND console = GetStdHandle(STD_OUTPUT_HANDLE); WORD color; DWORD read_len; CONSOLE_SCREEN_BUFFER_INFO info; if(console == INVALID_HANDLE_VALUE) { return lerror(L, "GetStdHandle"); } if(!GetConsoleScreenBufferInfo(console, &info)) { return lerror(L, "GetConsoleScreenBufferInfo"); } if(!ReadConsoleOutputAttribute(console, &color, 1, info.dwCursorPosition, &read_len)) { return lerror(L, "ReadConsoleOutputAttribute"); } lua_pushnumber(L, color); return 1; } static int Lset_consolecolor(lua_State *L) { int color = luaL_checkint(L, 1); HWND console = GetStdHandle(STD_OUTPUT_HANDLE); if(console == INVALID_HANDLE_VALUE) { return lerror(L, "GetStdHandle"); } if(!SetConsoleTextAttribute(console, color)) { return lerror(L, "SetConsoleTextAttribute"); } lua_pushboolean(L, 1); return 1; } static const luaL_Reg Reg[] = { { "get_nameservers", Lget_nameservers }, { "get_consolecolor", Lget_consolecolor }, { "set_consolecolor", Lset_consolecolor }, { NULL, NULL } }; LUALIB_API int luaopen_util_windows(lua_State *L) { #if (LUA_VERSION_NUM > 501) luaL_checkversion(L); #endif lua_newtable(L); luaL_setfuncs(L, Reg, 0); lua_pushliteral(L, "-3.14"); lua_setfield(L, -2, "version"); return 1; }