Added os.getpass

Prompt the user to enter a password and don't encho their entry.

src/host/os_getpass.c

@@ -0,0 +1,38 @@
+/**
+ * \file   os_getpass.c
+ * \brief  Prompt and retrieve a password from the user.
+ * \author Copyright (c) 2002-2008 Jason Perkins and the Premake project
+ */
+
+#include "premake.h"
+
+
+int os_getpass(lua_State* L)
+{
+	const char* prompt = luaL_checkstring(L, 1);
+
+	#if PLATFORM_WINDOWS
+		HANDLE hstdout = GetStdHandle(STD_OUTPUT_HANDLE);
+		HANDLE hstdin = GetStdHandle(STD_INPUT_HANDLE);
+		DWORD read_chars, mode, written_chars;
+		char buffer[1024];
+		const char* newline = "\n";
+
+		WriteConsoleA(hstdout, prompt, strlen(prompt), &written_chars, NULL);
+
+		GetConsoleMode(hstdin, &mode);
+		SetConsoleMode(hstdin, ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT);
+		ReadConsoleA(hstdin, buffer, sizeof (buffer), &read_chars, NULL);
+		SetConsoleMode(hstdin, mode);
+
+		WriteConsoleA(hstdout, newline, strlen(newline), &written_chars, NULL);
+
+		StrTrimA(buffer, "\r\n");
+
+		lua_pushstring(L, buffer);
+		return 1;
+	#else
+		lua_pushstring(L, getpass(prompt));
+		return 1;
+	#endif
+}

src/host/premake.c

@@ -57,6 +57,7 @@ static const luaL_Reg os_functions[] = {
 	{ "_is64bit",               os_is64bit              },
 	{ "isdir",                  os_isdir                },
 	{ "getcwd",                 os_getcwd               },
+	{ "getpass",                os_getpass              },
 	{ "getversion",             os_getversion           },
 	{ "isfile",                 os_isfile               },
 	{ "islink",                 os_islink               },

src/host/premake.h

@@ -103,6 +103,7 @@ int os_chdir(lua_State* L);
 int os_chmod(lua_State* L);
 int os_copyfile(lua_State* L);
 int os_getcwd(lua_State* L);
+int os_getpass(lua_State* L);
 int os_getversion(lua_State* L);
 int os_is64bit(lua_State* L);
 int os_isdir(lua_State* L);