Lua mount filesystem - lua

Question

I want to mount a filesystem on Linux using Lua, but I haven't found any capability in the lua 5.4 manual or the LuaFileSytem library. Is there some way to mount a filesystem in Lua or with an existing library?

Answer 1

Like most platform-dependent syscall, Lua won't provide such mapping out of the box.
So you'll need some C-API module that does the trick.
Looks like https://github.com/justincormack/ljsyscall is generic "but" focused on LuaJIT and https://luaposix.github.io/luaposix/ doesn't provide mount.
I recently had similar needs, and I ended doing the C module:
static int l_mount(lua_State* L)
{
int res = 0;
// TODO add more checks on args!
const char *source = luaL_checkstring(L, 1);
const char *target = luaL_checkstring(L, 2);
const char *type = luaL_checkstring(L, 3);
lua_Integer flags = luaL_checkinteger(L, 4);
const char *data = luaL_checkstring(L, 5);
res = mount(source, target, type, flags, data);
if ( res != 0)
{
int err = errno;
lua_pushnil(L);
lua_pushfstring(L, "mount failed: errno[%s]", strerror(err));
return 2;
}
else
{
lua_pushfstring(L, "ok");
return 1;
}
}
#define register_constant(s)\
lua_pushinteger(L, s);\
lua_setfield(L, -2, #s);
// Module functions
static const luaL_Reg R[] =
{
{ "mount", l_mount },
{ NULL, NULL }
};
int luaopen_sysutils(lua_State* L)
{
luaL_newlib(L, R);
// do more mount defines mapping, maybe in some table.
register_constant(MS_RDONLY);
//...
return 1;
}
Compile this as a C Lua module, and don't forget that you need CAP_SYS_ADMIN to call mount syscall.