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69 lines
1.3 KiB
69 lines
1.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/types.h> |
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#include <linux/errno.h> |
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#include <linux/tty.h> |
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#include <linux/module.h> |
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/* |
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* n_null.c - Null line discipline used in the failure path |
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* |
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* Copyright (C) Intel 2017 |
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*/ |
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static int n_null_open(struct tty_struct *tty) |
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{ |
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return 0; |
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} |
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static void n_null_close(struct tty_struct *tty) |
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{ |
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} |
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static ssize_t n_null_read(struct tty_struct *tty, struct file *file, |
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unsigned char *buf, size_t nr, |
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void **cookie, unsigned long offset) |
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{ |
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return -EOPNOTSUPP; |
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} |
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static ssize_t n_null_write(struct tty_struct *tty, struct file *file, |
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const unsigned char *buf, size_t nr) |
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{ |
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return -EOPNOTSUPP; |
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} |
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static void n_null_receivebuf(struct tty_struct *tty, |
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const unsigned char *cp, char *fp, |
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int cnt) |
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{ |
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} |
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static struct tty_ldisc_ops null_ldisc = { |
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.owner = THIS_MODULE, |
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.magic = TTY_LDISC_MAGIC, |
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.name = "n_null", |
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.open = n_null_open, |
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.close = n_null_close, |
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.read = n_null_read, |
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.write = n_null_write, |
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.receive_buf = n_null_receivebuf |
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}; |
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static int __init n_null_init(void) |
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{ |
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BUG_ON(tty_register_ldisc(N_NULL, &null_ldisc)); |
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return 0; |
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} |
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static void __exit n_null_exit(void) |
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{ |
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tty_unregister_ldisc(N_NULL); |
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} |
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module_init(n_null_init); |
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module_exit(n_null_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Alan Cox"); |
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MODULE_ALIAS_LDISC(N_NULL); |
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MODULE_DESCRIPTION("Null ldisc driver");
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