projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 567b5650 PBG |
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 | */ | |
| 1da177e4 LT |
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" | |
| 1da177e4 LT |
20 | |
| 21 | #define RNG_MISCDEV_MINOR 183 /* official */ | |
| 22 | ||
| 23 | static int random_fd = -1; | |
| 24 | ||
| 25 | static 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 | ||
| 36 | static 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 | ||
| 73 | static struct file_operations rng_chrdev_ops = { | |
| 74 | .owner = THIS_MODULE, | |
| 75 | .open = rng_dev_open, | |
| 76 | .read = rng_dev_read, | |
| 77 | }; | |
| 78 | ||
| 79 | static 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 | */ | |
| 88 | static 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) { | |
| 567b5650 | 104 | printk (KERN_ERR RNG_MODULE_NAME ": misc device register failed\n"); |
| 1da177e4 LT |
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 | */ | |
| 119 | static void __exit rng_cleanup (void) | |
| 120 | { | |
| 121 | misc_deregister (&rng_miscdev); | |
| 122 | } | |
| 123 | ||
| 124 | module_init (rng_init); | |
| 125 | module_exit (rng_cleanup); | |
| 567b5650 PBG |
126 | |
| 127 | MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver"); | |
| 128 | MODULE_LICENSE("GPL"); |