162306a36Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0 262306a36Sopenharmony_ci/* 362306a36Sopenharmony_ci * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com) 462306a36Sopenharmony_ci */ 562306a36Sopenharmony_ci 662306a36Sopenharmony_ci#include <stddef.h> 762306a36Sopenharmony_ci#include <errno.h> 862306a36Sopenharmony_ci#include <fcntl.h> 962306a36Sopenharmony_ci#include "chan_user.h" 1062306a36Sopenharmony_ci#include <os.h> 1162306a36Sopenharmony_ci 1262306a36Sopenharmony_ci/* This address is used only as a unique identifier */ 1362306a36Sopenharmony_cistatic int null_chan; 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_cistatic void *null_init(char *str, int device, const struct chan_opts *opts) 1662306a36Sopenharmony_ci{ 1762306a36Sopenharmony_ci return &null_chan; 1862306a36Sopenharmony_ci} 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_cistatic int null_open(int input, int output, int primary, void *d, 2162306a36Sopenharmony_ci char **dev_out) 2262306a36Sopenharmony_ci{ 2362306a36Sopenharmony_ci int fd; 2462306a36Sopenharmony_ci 2562306a36Sopenharmony_ci *dev_out = NULL; 2662306a36Sopenharmony_ci 2762306a36Sopenharmony_ci fd = open(DEV_NULL, O_RDWR); 2862306a36Sopenharmony_ci return (fd < 0) ? -errno : fd; 2962306a36Sopenharmony_ci} 3062306a36Sopenharmony_ci 3162306a36Sopenharmony_cistatic int null_read(int fd, char *c_out, void *unused) 3262306a36Sopenharmony_ci{ 3362306a36Sopenharmony_ci return -ENODEV; 3462306a36Sopenharmony_ci} 3562306a36Sopenharmony_ci 3662306a36Sopenharmony_cistatic void null_free(void *data) 3762306a36Sopenharmony_ci{ 3862306a36Sopenharmony_ci} 3962306a36Sopenharmony_ci 4062306a36Sopenharmony_ciconst struct chan_ops null_ops = { 4162306a36Sopenharmony_ci .type = "null", 4262306a36Sopenharmony_ci .init = null_init, 4362306a36Sopenharmony_ci .open = null_open, 4462306a36Sopenharmony_ci .close = generic_close, 4562306a36Sopenharmony_ci .read = null_read, 4662306a36Sopenharmony_ci .write = generic_write, 4762306a36Sopenharmony_ci .console_write = generic_console_write, 4862306a36Sopenharmony_ci .window_size = generic_window_size, 4962306a36Sopenharmony_ci .free = null_free, 5062306a36Sopenharmony_ci .winch = 0, 5162306a36Sopenharmony_ci}; 52