Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* Copyright (C) 2005 Jeff Dike <jdike@addtoit.com> */
2/* Much of this ripped from drivers/char/hw_random.c, see there for other
3 * copyright.
4 *
5 * This software may be used and distributed according to the terms
6 * of the GNU General Public License, incorporated herein by reference.
7 */
8#include <linux/module.h>
9#include <linux/fs.h>
10#include <linux/miscdevice.h>
11#include <linux/delay.h>
12#include <asm/uaccess.h>
13#include "os.h"
14
15/*
16 * core module and version information
17 */
18#define RNG_VERSION "1.0.0"
19#define RNG_MODULE_NAME "random"
20
21#define RNG_MISCDEV_MINOR 183 /* official */
22
23static int random_fd = -1;
24
25static int rng_dev_open (struct inode *inode, struct file *filp)
26{
27 /* enforce read-only access to this chrdev */
28 if ((filp->f_mode & FMODE_READ) == 0)
29 return -EINVAL;
30 if (filp->f_mode & FMODE_WRITE)
31 return -EINVAL;
32
33 return 0;
34}
35
36static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size,
37 loff_t * offp)
38{
39 u32 data;
40 int n, ret = 0, have_data;
41
42 while(size){
43 n = os_read_file(random_fd, &data, sizeof(data));
44 if(n > 0){
45 have_data = n;
46 while (have_data && size) {
47 if (put_user((u8)data, buf++)) {
48 ret = ret ? : -EFAULT;
49 break;
50 }
51 size--;
52 ret++;
53 have_data--;
54 data>>=8;
55 }
56 }
57 else if(n == -EAGAIN){
58 if (filp->f_flags & O_NONBLOCK)
59 return ret ? : -EAGAIN;
60
61 if(need_resched()){
62 current->state = TASK_INTERRUPTIBLE;
63 schedule_timeout(1);
64 }
65 }
66 else return n;
67 if (signal_pending (current))
68 return ret ? : -ERESTARTSYS;
69 }
70 return ret;
71}
72
73static struct file_operations rng_chrdev_ops = {
74 .owner = THIS_MODULE,
75 .open = rng_dev_open,
76 .read = rng_dev_read,
77};
78
79static struct miscdevice rng_miscdev = {
80 RNG_MISCDEV_MINOR,
81 RNG_MODULE_NAME,
82 &rng_chrdev_ops,
83};
84
85/*
86 * rng_init - initialize RNG module
87 */
88static int __init rng_init (void)
89{
90 int err;
91
92 err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0);
93 if(err < 0)
94 goto out;
95
96 random_fd = err;
97
98 err = os_set_fd_block(random_fd, 0);
99 if(err)
100 goto err_out_cleanup_hw;
101
102 err = misc_register (&rng_miscdev);
103 if (err) {
104 printk (KERN_ERR RNG_MODULE_NAME ": misc device register failed\n");
105 goto err_out_cleanup_hw;
106 }
107
108 out:
109 return err;
110
111 err_out_cleanup_hw:
112 random_fd = -1;
113 goto out;
114}
115
116/*
117 * rng_cleanup - shutdown RNG module
118 */
119static void __exit rng_cleanup (void)
120{
121 misc_deregister (&rng_miscdev);
122}
123
124module_init (rng_init);
125module_exit (rng_cleanup);
126
127MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
128MODULE_LICENSE("GPL");