Beispiel #1
0
static ERL_NIF_TERM open_nif(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]) {
    posix_errno_t posix_errno;
    efile_data_t *d;

    ErlNifPid controlling_process;
    enum efile_modes_t modes;
    ERL_NIF_TERM result;
    efile_path_t path;

    if(argc != 2 || !enif_is_list(env, argv[1])) {
        return enif_make_badarg(env);
    }

    modes = efile_translate_modelist(env, argv[1]);

    if((posix_errno = efile_marshal_path(env, argv[0], &path))) {
        return posix_error_to_tuple(env, posix_errno);
    } else if((posix_errno = efile_open(&path, modes, efile_resource_type, &d))) {
        return posix_error_to_tuple(env, posix_errno);
    }

    result = enif_make_resource(env, d);
    enif_release_resource(d);

    enif_self(env, &controlling_process);

    if(enif_monitor_process(env, d, &controlling_process, &d->monitor)) {
        return posix_error_to_tuple(env, EINVAL);
    }

    return enif_make_tuple2(env, am_ok, result);
}
Beispiel #2
0
static ERL_NIF_TERM open_nif(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]) {
    posix_errno_t posix_errno;
    efile_data_t *d;

    ErlNifPid controlling_process;
    enum efile_modes_t modes;
    ERL_NIF_TERM result;
    efile_path_t path;

    ASSERT(argc == 2);
    if(!enif_is_list(env, argv[1])) {
        return enif_make_badarg(env);
    }

    modes = efile_translate_modelist(env, argv[1]);

    if((posix_errno = efile_marshal_path(env, argv[0], &path))) {
        return posix_error_to_tuple(env, posix_errno);
    } else if((posix_errno = efile_open(&path, modes, efile_resource_type, &d))) {
        return posix_error_to_tuple(env, posix_errno);
    }

    enif_self(env, &controlling_process);

    if(enif_monitor_process(env, d, &controlling_process, &d->monitor)) {
        /* We need to close the file manually as we haven't registered a
         * destructor. */
        posix_errno_t ignored;

        erts_atomic32_set_acqb(&d->state, EFILE_STATE_CLOSED);
        efile_close(d, &ignored);

        return posix_error_to_tuple(env, EINVAL);
    }

    /* Note that we do not call enif_release_resource at this point. While it's
     * normally safe to leave resource management to the GC, efile_close is a
     * blocking operation which must not be done in the GC callback, and we
     * can't defer it as the resource is gone as soon as it returns.
     *
     * We instead keep the resource alive until efile_close is called, after
     * which it's safe to leave things to the GC. If the controlling process
     * were to die before the user had a chance to close their file, the above
     * monitor will tell the erts_prim_file process to close it for them. */
    result = enif_make_resource(env, d);

    return enif_make_tuple2(env, am_ok, result);
}