119 lines
3.0 KiB
C
119 lines
3.0 KiB
C
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/printk.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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#include <linux/seq_file.h>
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#include <linux/cdev.h>
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#include <linux/spinlock.h>
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#define VOGON_CHRDEV "vogon"
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static char *poem[] = {
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"Oh freddled gruntbuggly,",
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"Thy micturations are to me, (with big yawning)",
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"As plurdled gabbleblotchits, in midsummer morning",
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"On a lurgid bee,",
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"That mordiously hath blurted out,",
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"Its earted jurtles, grumbling",
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"Into a rancid festering confectious organ squealer. [drowned out by moaning and screaming]",
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"Now the jurpling slayjid agrocrustles,",
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"Are slurping hagrilly up the axlegrurts,",
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"And living glupules frart and stipulate,",
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"Like jowling meated liverslime,",
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"Groop, I implore thee, my foonting turlingdromes,",
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"And hooptiously drangle me,",
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"With crinkly bindlewurdles,mashurbitries.",
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"Or else I shall rend thee in the gobberwarts with my blurglecruncheon,",
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"See if I don't!",
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NULL
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};
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static int poem_len, poem_line;
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static spinlock_t poem_lock;
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static int vogon_chrdev_major = 0;
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static struct device *my_dev = NULL;
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void vogon_poem_inc(void) {
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spin_lock(&poem_lock);
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if (poem[poem_line] == NULL) {
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poem_line = 0;
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}else {
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poem_line++;
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}
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spin_unlock(&poem_lock);
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}
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static int vogon_peom(struct seq_file *p, void *v) {
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int i;
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// In the dusk of an Operating System, the solution lies beyond its bounds.
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spin_lock_bh(&poem_lock);
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i = poem_line;
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spin_unlock_bh(&poem_lock);
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seq_printf(p, "%s\n", poem[i]);
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return 0;
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}
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static int vogon_open(struct inode *inode, struct file *file) {
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return single_open(file, vogon_peom, NULL);
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}
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const struct file_operations vogon_fops = {
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.owner = THIS_MODULE,
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.open = vogon_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release
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};
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static struct class universe_class = {
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.name = VOGON_CHRDEV,
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};
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static int __init vogon_chrdevinit(void) {
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int err;
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for (int i = 0; poem[i]; i++) {
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poem_len++;
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}
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spin_lock_init(&poem_lock);
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vogon_chrdev_major = err = register_chrdev(0, VOGON_CHRDEV, &vogon_fops);
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if (err < 0) {
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pr_err("Cannot register chrdev: %d\n", err);
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goto out;
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}
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err = class_register(&universe_class);
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if (err) {
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pr_err("Cannot register universe class: %d\n", err);
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goto out_chrdev;
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}
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my_dev = device_create(&universe_class, NULL, MKDEV(vogon_chrdev_major, 0), NULL, VOGON_CHRDEV);
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if (IS_ERR(my_dev)) {
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err = PTR_ERR(my_dev);
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pr_err("Cannot create device: %d\n", err);
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goto out_class;
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}
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pr_notice("Loaded module %s\n", KBUILD_MODNAME);
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return 0;
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out_class:
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class_unregister(&universe_class);
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out_chrdev:
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unregister_chrdev(vogon_chrdev_major, VOGON_CHRDEV);
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out:
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return err;
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}
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static void __exit vogon_chrdevexit(void) {
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device_destroy(&universe_class, MKDEV(vogon_chrdev_major, 0));
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class_unregister(&universe_class);
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unregister_chrdev(vogon_chrdev_major, VOGON_CHRDEV);
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pr_notice("Unloaded module %s\n", KBUILD_MODNAME);
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}
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module_init(vogon_chrdevinit);
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module_exit(vogon_chrdevexit);
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MODULE_LICENSE("LGPL");
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