cregit-Linux how code gets into the kernel

Release 4.14 arch/um/drivers/random.c

Directory: arch/um/drivers
/* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */

/* Much of this ripped from drivers/char/hw_random.c, see there for other
 * copyright.
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 */
#include <linux/sched/signal.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <irq_kern.h>
#include <os.h>

/*
 * core module and version information
 */

#define RNG_VERSION "1.0.0"

#define RNG_MODULE_NAME "hw_random"


#define RNG_MISCDEV_MINOR		183 
/* official */

/* Changed at init time, in the non-modular case, and at module load
 * time, in the module case.  Presumably, the module subsystem
 * protects against a module being loaded twice at the same time.
 */

static int random_fd = -1;
static DECLARE_WAIT_QUEUE_HEAD(host_read_wait);


static int rng_dev_open (struct inode *inode, struct file *filp) { /* enforce read-only access to this chrdev */ if ((filp->f_mode & FMODE_READ) == 0) return -EINVAL; if ((filp->f_mode & FMODE_WRITE) != 0) return -EINVAL; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike52100.00%2100.00%
Total52100.00%2100.00%

static atomic_t host_sleep_count = ATOMIC_INIT(0);
static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size, loff_t *offp) { u32 data; int n, ret = 0, have_data; while (size) { n = os_read_file(random_fd, &data, sizeof(data)); if (n > 0) { have_data = n; while (have_data && size) { if (put_user((u8) data, buf++)) { ret = ret ? : -EFAULT; break; } size--; ret++; have_data--; data >>= 8; } } else if (n == -EAGAIN) { DECLARE_WAITQUEUE(wait, current); if (filp->f_flags & O_NONBLOCK) return ret ? : -EAGAIN; atomic_inc(&host_sleep_count); reactivate_fd(random_fd, RANDOM_IRQ); add_sigio_fd(random_fd); add_wait_queue(&host_read_wait, &wait); set_current_state(TASK_INTERRUPTIBLE); schedule(); remove_wait_queue(&host_read_wait, &wait); if (atomic_dec_and_test(&host_sleep_count)) { ignore_sigio_fd(random_fd); deactivate_fd(random_fd, RANDOM_IRQ); } } else return n; if (signal_pending (current)) return ret ? : -ERESTARTSYS; } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike23199.57%375.00%
Davidlohr Bueso A10.43%125.00%
Total232100.00%4100.00%

static const struct file_operations rng_chrdev_ops = { .owner = THIS_MODULE, .open = rng_dev_open, .read = rng_dev_read, .llseek = noop_llseek, }; /* rng_init shouldn't be called more than once at boot time */ static struct miscdevice rng_miscdev = { RNG_MISCDEV_MINOR, RNG_MODULE_NAME, &rng_chrdev_ops, };
static irqreturn_t random_interrupt(int irq, void *data) { wake_up(&host_read_wait); return IRQ_HANDLED; }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike22100.00%1100.00%
Total22100.00%1100.00%

/* * rng_init - initialize RNG module */
static int __init rng_init (void) { int err; err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0); if (err < 0) goto out; random_fd = err; err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt, 0, "random", NULL); if (err) goto err_out_cleanup_hw; sigio_broken(random_fd, 1); err = misc_register (&rng_miscdev); if (err) { printk (KERN_ERR RNG_MODULE_NAME ": misc device register " "failed\n"); goto err_out_cleanup_hw; } out: return err; err_out_cleanup_hw: os_close_file(random_fd); random_fd = -1; goto out; }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike11598.29%360.00%
Theodore Y. Ts'o10.85%120.00%
Paolo 'Blaisorblade' Giarrusso10.85%120.00%
Total117100.00%5100.00%

/* * rng_cleanup - shutdown RNG module */
static void __exit rng_cleanup (void) { os_close_file(random_fd); misc_deregister (&rng_miscdev); }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike20100.00%2100.00%
Total20100.00%2100.00%

module_init (rng_init); module_exit (rng_cleanup); MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver"); MODULE_LICENSE("GPL");

Overall Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike55195.99%853.33%
Paolo 'Blaisorblade' Giarrusso122.09%16.67%
Arnd Bergmann50.87%16.67%
Al Viro20.35%16.67%
Theodore Y. Ts'o10.17%16.67%
Davidlohr Bueso A10.17%16.67%
Linus Torvalds10.17%16.67%
Ingo Molnar10.17%16.67%
Total574100.00%15100.00%
Directory: arch/um/drivers
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.