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p1_scull/access.c0000644000175000017500000002565612126651741012406 0ustar mwkmwk/*
* access.c -- the files with access control on open
*
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
* $Id: access.c,v 1.17 2004/09/26 07:29:56 gregkh Exp $
*/
/* FIXME: cloned devices as a use for kobjects? */
#include <linux/kernel.h> /* printk() */
#include <linux/module.h>
#include <linux/slab.h> /* kmalloc() */
#include <linux/fs.h> /* everything... */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/fcntl.h>
#include <linux/cdev.h>
#include <linux/tty.h>
#include <asm/atomic.h>
#include <linux/list.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include "scull.h" /* local definitions */
static dev_t scull_a_firstdev; /* Where our range begins */
/*
* These devices fall back on the main scull operations. They only
* differ in the implementation of open() and close()
*/
/************************************************************************
*
* The first device is the single-open one,
* it has an hw structure and an open count
*/
static struct scull_dev scull_s_device;
static atomic_t scull_s_available = ATOMIC_INIT(1);
static int scull_s_open(struct inode *inode, struct file *filp)
{
struct scull_dev *dev = &scull_s_device; /* device information */
if (! atomic_dec_and_test (&scull_s_available)) {
atomic_inc(&scull_s_available);
return -EBUSY; /* already open */
}
/* then, everything else is copied from the bare scull device */
if ( (filp->f_flags & O_ACCMODE) == O_WRONLY)
scull_trim(dev);
filp->private_data = dev;
return 0; /* success */
}
static int scull_s_release(struct inode *inode, struct file *filp)
{
atomic_inc(&scull_s_available); /* release the device */
return 0;
}
/*
* The other operations for the single-open device come from the bare device
*/
struct file_operations scull_sngl_fops = {
.owner = THIS_MODULE,
.llseek = scull_llseek,
.read = scull_read,
.write = scull_write,
.unlocked_ioctl = scull_ioctl,
.open = scull_s_open,
.release = scull_s_release,
};
/************************************************************************
*
* Next, the "uid" device. It can be opened multiple times by the
* same user, but access is denied to other users if the device is open
*/
static struct scull_dev scull_u_device;
static int scull_u_count; /* initialized to 0 by default */
static uid_t scull_u_owner; /* initialized to 0 by default */
static DEFINE_SPINLOCK(scull_u_lock);
static int scull_u_open(struct inode *inode, struct file *filp)
{
struct scull_dev *dev = &scull_u_device; /* device information */
spin_lock(&scull_u_lock);
if (scull_u_count &&
(scull_u_owner != current_uid()) && /* allow user */
(scull_u_owner != current_euid()) && /* allow whoever did su */
!capable(CAP_DAC_OVERRIDE)) { /* still allow root */
spin_unlock(&scull_u_lock);
return -EBUSY; /* -EPERM would confuse the user */
}
if (scull_u_count == 0)
scull_u_owner = current_uid(); /* grab it */
scull_u_count++;
spin_unlock(&scull_u_lock);
/* then, everything else is copied from the bare scull device */
if ((filp->f_flags & O_ACCMODE) == O_WRONLY)
scull_trim(dev);
filp->private_data = dev;
return 0; /* success */
}
static int scull_u_release(struct inode *inode, struct file *filp)
{
spin_lock(&scull_u_lock);
scull_u_count--; /* nothing else */
spin_unlock(&scull_u_lock);
return 0;
}
/*
* The other operations for the device come from the bare device
*/
struct file_operations scull_user_fops = {
.owner = THIS_MODULE,
.llseek = scull_llseek,
.read = scull_read,
.write = scull_write,
.unlocked_ioctl = scull_ioctl,
.open = scull_u_open,
.release = scull_u_release,
};
/************************************************************************
*
* Next, the device with blocking-open based on uid
*/
static struct scull_dev scull_w_device;
static int scull_w_count; /* initialized to 0 by default */
static uid_t scull_w_owner; /* initialized to 0 by default */
static DECLARE_WAIT_QUEUE_HEAD(scull_w_wait);
static DEFINE_SPINLOCK(scull_w_lock);
static inline int scull_w_available(void)
{
return scull_w_count == 0 ||
scull_w_owner == current_uid() ||
scull_w_owner == current_euid() ||
capable(CAP_DAC_OVERRIDE);
}
static int scull_w_open(struct inode *inode, struct file *filp)
{
struct scull_dev *dev = &scull_w_device; /* device information */
spin_lock(&scull_w_lock);
while (! scull_w_available()) {
spin_unlock(&scull_w_lock);
if (filp->f_flags & O_NONBLOCK) return -EAGAIN;
if (wait_event_interruptible (scull_w_wait, scull_w_available()))
return -ERESTARTSYS; /* tell the fs layer to handle it */
spin_lock(&scull_w_lock);
}
if (scull_w_count == 0)
scull_w_owner = current_uid(); /* grab it */
scull_w_count++;
spin_unlock(&scull_w_lock);
/* then, everything else is copied from the bare scull device */
if ((filp->f_flags & O_ACCMODE) == O_WRONLY)
scull_trim(dev);
filp->private_data = dev;
return 0; /* success */
}
static int scull_w_release(struct inode *inode, struct file *filp)
{
int temp;
spin_lock(&scull_w_lock);
scull_w_count--;
temp = scull_w_count;
spin_unlock(&scull_w_lock);
if (temp == 0)
wake_up_interruptible_sync(&scull_w_wait); /* awake other uid's */
return 0;
}
/*
* The other operations for the device come from the bare device
*/
struct file_operations scull_wusr_fops = {
.owner = THIS_MODULE,
.llseek = scull_llseek,
.read = scull_read,
.write = scull_write,
.unlocked_ioctl = scull_ioctl,
.open = scull_w_open,
.release = scull_w_release,
};
/************************************************************************
*
* Finally the `cloned' private device. This is trickier because it
* involves list management, and dynamic allocation.
*/
/* The clone-specific data structure includes a key field */
struct scull_listitem {
struct scull_dev device;
dev_t key;
struct list_head list;
};
/* The list of devices, and a lock to protect it */
static LIST_HEAD(scull_c_list);
static DEFINE_SPINLOCK(scull_c_lock);
/* A placeholder scull_dev which really just holds the cdev stuff. */
static struct scull_dev scull_c_device;
/* Look for a device or create one if missing */
static struct scull_dev *scull_c_lookfor_device(dev_t key)
{
struct scull_listitem *lptr;
list_for_each_entry(lptr, &scull_c_list, list) {
if (lptr->key == key)
return &(lptr->device);
}
/* not found */
lptr = kmalloc(sizeof(struct scull_listitem), GFP_KERNEL);
if (!lptr)
return NULL;
/* initialize the device */
memset(lptr, 0, sizeof(struct scull_listitem));
lptr->key = key;
scull_trim(&(lptr->device)); /* initialize it */
sema_init(&(lptr->device.sem), 1);
/* place it in the list */
list_add(&lptr->list, &scull_c_list);
return &(lptr->device);
}
static int scull_c_open(struct inode *inode, struct file *filp)
{
struct scull_dev *dev;
dev_t key;
if (!current->signal->tty) {
PDEBUG("Process \"%s\" has no ctl tty\n", current->comm);
return -EINVAL;
}
key = tty_devnum(current->signal->tty);
/* look for a scullc device in the list */
spin_lock(&scull_c_lock);
dev = scull_c_lookfor_device(key);
spin_unlock(&scull_c_lock);
if (!dev)
return -ENOMEM;
/* then, everything else is copied from the bare scull device */
if ( (filp->f_flags & O_ACCMODE) == O_WRONLY)
scull_trim(dev);
filp->private_data = dev;
return 0; /* success */
}
static int scull_c_release(struct inode *inode, struct file *filp)
{
/*
* Nothing to do, because the device is persistent.
* A `real' cloned device should be freed on last close
*/
return 0;
}
/*
* The other operations for the device come from the bare device
*/
struct file_operations scull_priv_fops = {
.owner = THIS_MODULE,
.llseek = scull_llseek,
.read = scull_read,
.write = scull_write,
.unlocked_ioctl = scull_ioctl,
.open = scull_c_open,
.release = scull_c_release,
};
/************************************************************************
*
* And the init and cleanup functions come last
*/
static struct scull_adev_info {
char *name;
struct scull_dev *sculldev;
struct file_operations *fops;
} scull_access_devs[] = {
{ "scullsingle", &scull_s_device, &scull_sngl_fops },
{ "sculluid", &scull_u_device, &scull_user_fops },
{ "scullwuid", &scull_w_device, &scull_wusr_fops },
{ "scullpriv", &scull_c_device, &scull_priv_fops }
};
#define SCULL_N_ADEVS 4
/*
* Set up a single device.
*/
static void scull_access_setup (dev_t devno, struct scull_adev_info *devinfo)
{
struct scull_dev *dev = devinfo->sculldev;
int err;
/* Initialize the device structure */
dev->quantum = scull_quantum;
dev->qset = scull_qset;
sema_init(&dev->sem, 1);
/* Do the cdev stuff. */
dev->devno = devno;
cdev_init(&dev->cdev, devinfo->fops);
kobject_set_name(&dev->cdev.kobj, devinfo->name);
dev->cdev.owner = THIS_MODULE;
err = cdev_add (&dev->cdev, devno, 1);
/* Fail gracefully if need be */
if (err) {
printk(KERN_NOTICE "Error %d adding %s\n", err, devinfo->name);
kobject_put(&dev->cdev.kobj);
return;
} else
printk(KERN_NOTICE "%s registered at %x\n", devinfo->name, devno);
dev->dev = device_create(scull_class, 0, dev->devno, 0, "%s", devinfo->name);
if (IS_ERR(dev->dev)) {
printk(KERN_NOTICE "Error %ld adding %s to sysfs", PTR_ERR(dev->dev), devinfo->name);
dev->dev = 0;
}
}
int scull_access_init(dev_t firstdev)
{
int result, i;
/* Get our number space */
result = register_chrdev_region (firstdev, SCULL_N_ADEVS, "sculla");
if (result < 0) {
printk(KERN_WARNING "sculla: device number registration failed\n");
return 0;
}
scull_a_firstdev = firstdev;
/* Set up each device. */
for (i = 0; i < SCULL_N_ADEVS; i++)
scull_access_setup (firstdev + i, scull_access_devs + i);
return SCULL_N_ADEVS;
}
/*
* This is called by cleanup_module or on failure.
* It is required to never fail, even if nothing was initialized first
*/
void scull_access_cleanup(void)
{
struct scull_listitem *lptr, *next;
int i;
/* Clean up the static devs */
for (i = 0; i < SCULL_N_ADEVS; i++) {
struct scull_dev *dev = scull_access_devs[i].sculldev;
device_destroy(scull_class, dev->devno);
cdev_del(&dev->cdev);
scull_trim(scull_access_devs[i].sculldev);
}
/* And all the cloned devices */
list_for_each_entry_safe(lptr, next, &scull_c_list, list) {
list_del(&lptr->list);
scull_trim(&(lptr->device));
kfree(lptr);
}
/* Free up our number space */
unregister_chrdev_region(scull_a_firstdev, SCULL_N_ADEVS);
return;
}
p1_scull/main.c0000644000175000017500000004072412312246524012056 0ustar mwkmwk/*
* main.c -- the bare scull char module
*
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/fs.h> /* everything... */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/proc_fs.h>
#include <linux/fcntl.h> /* O_ACCMODE */
#include <linux/seq_file.h>
#include <linux/cdev.h>
#include <asm/uaccess.h> /* copy_*_user */
#include "scull.h" /* local definitions */
/*
* Our parameters which can be set at load time.
*/
int scull_major = SCULL_MAJOR;
int scull_minor = 0;
int scull_nr_devs = SCULL_NR_DEVS; /* number of bare scull devices */
int scull_quantum = SCULL_QUANTUM;
int scull_qset = SCULL_QSET;
module_param(scull_major, int, S_IRUGO);
module_param(scull_minor, int, S_IRUGO);
module_param(scull_nr_devs, int, S_IRUGO);
module_param(scull_quantum, int, S_IRUGO);
module_param(scull_qset, int, S_IRUGO);
MODULE_AUTHOR("Alessandro Rubini, Jonathan Corbet");
MODULE_LICENSE("Dual BSD/GPL");
struct class *scull_class;
struct scull_dev *scull_devices; /* allocated in scull_init_module */
/*
* Empty out the scull device; must be called with the device
* semaphore held.
*/
int scull_trim(struct scull_dev *dev)
{
struct scull_qset *next, *dptr;
int qset = dev->qset; /* "dev" is not-null */
int i;
for (dptr = dev->data; dptr; dptr = next) { /* all the list items */
if (dptr->data) {
for (i = 0; i < qset; i++)
kfree(dptr->data[i]);
kfree(dptr->data);
dptr->data = NULL;
}
next = dptr->next;
kfree(dptr);
}
dev->size = 0;
dev->quantum = scull_quantum;
dev->qset = scull_qset;
dev->data = NULL;
return 0;
}
#ifdef SCULL_DEBUG /* use proc only if debugging */
/*
* The proc filesystem: function to read and entry
*/
int scull_read_procmem(char *buf, char **start, off_t offset,
int count, int *eof, void *data)
{
int i, j, len = 0;
int limit = count - 80; /* Don't print more than this */
for (i = 0; i < scull_nr_devs && len <= limit; i++) {
struct scull_dev *d = &scull_devices[i];
struct scull_qset *qs = d->data;
if (down_interruptible(&d->sem))
return -ERESTARTSYS;
len += sprintf(buf+len,"\nDevice %i: qset %i, q %i, sz %li\n",
i, d->qset, d->quantum, d->size);
for (; qs && len <= limit; qs = qs->next) { /* scan the list */
len += sprintf(buf + len, " item at %p, qset at %p\n",
qs, qs->data);
if (qs->data && !qs->next) /* dump only the last item */
for (j = 0; j < d->qset; j++) {
if (qs->data[j])
len += sprintf(buf + len,
" % 4i: %8p\n",
j, qs->data[j]);
}
}
up(&scull_devices[i].sem);
}
*eof = 1;
return len;
}
/*
* For now, the seq_file implementation will exist in parallel. The
* older read_procmem function should maybe go away, though.
*/
/*
* Here are our sequence iteration methods. Our "position" is
* simply the device number.
*/
static void *scull_seq_start(struct seq_file *s, loff_t *pos)
{
if (*pos >= scull_nr_devs)
return NULL; /* No more to read */
return scull_devices + *pos;
}
static void *scull_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
(*pos)++;
if (*pos >= scull_nr_devs)
return NULL;
return scull_devices + *pos;
}
static void scull_seq_stop(struct seq_file *s, void *v)
{
/* Actually, there's nothing to do here */
}
static int scull_seq_show(struct seq_file *s, void *v)
{
struct scull_dev *dev = (struct scull_dev *) v;
struct scull_qset *d;
int i;
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
seq_printf(s, "\nDevice %i: qset %i, q %i, sz %li\n",
(int) (dev - scull_devices), dev->qset,
dev->quantum, dev->size);
for (d = dev->data; d; d = d->next) { /* scan the list */
seq_printf(s, " item at %p, qset at %p\n", d, d->data);
if (d->data && !d->next) /* dump only the last item */
for (i = 0; i < dev->qset; i++) {
if (d->data[i])
seq_printf(s, " % 4i: %8p\n",
i, d->data[i]);
}
}
up(&dev->sem);
return 0;
}
/*
* Tie the sequence operators up.
*/
static struct seq_operations scull_seq_ops = {
.start = scull_seq_start,
.next = scull_seq_next,
.stop = scull_seq_stop,
.show = scull_seq_show
};
/*
* Now to implement the /proc file we need only make an open
* method which sets up the sequence operators.
*/
static int scull_proc_open(struct inode *inode, struct file *file)
{
return seq_open(file, &scull_seq_ops);
}
/*
* Create a set of file operations for our proc file.
*/
static struct file_operations scull_proc_ops = {
.owner = THIS_MODULE,
.open = scull_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release
};
/*
* Actually create (and remove) the /proc file(s).
*/
static void scull_create_proc(void)
{
struct proc_dir_entry *entry;
create_proc_read_entry("scullmem", 0 /* default mode */,
NULL /* parent dir */, scull_read_procmem,
NULL /* client data */);
entry = create_proc_entry("scullseq", 0, NULL);
if (entry)
entry->proc_fops = &scull_proc_ops;
}
static void scull_remove_proc(void)
{
/* no problem if it was not registered */
remove_proc_entry("scullmem", NULL /* parent dir */);
remove_proc_entry("scullseq", NULL);
}
#endif /* SCULL_DEBUG */
/*
* Open and close
*/
int scull_open(struct inode *inode, struct file *filp)
{
struct scull_dev *dev; /* device information */
dev = container_of(inode->i_cdev, struct scull_dev, cdev);
filp->private_data = dev; /* for other methods */
/* now trim to 0 the length of the device if open was write-only */
if ( (filp->f_flags & O_ACCMODE) == O_WRONLY) {
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
scull_trim(dev); /* ignore errors */
up(&dev->sem);
}
return 0; /* success */
}
int scull_release(struct inode *inode, struct file *filp)
{
return 0;
}
/*
* Follow the list
*/
struct scull_qset *scull_follow(struct scull_dev *dev, int n)
{
struct scull_qset *qs = dev->data;
/* Allocate first qset explicitly if need be */
if (! qs) {
qs = dev->data = kmalloc(sizeof(struct scull_qset), GFP_KERNEL);
if (qs == NULL)
return NULL; /* Never mind */
memset(qs, 0, sizeof(struct scull_qset));
}
/* Then follow the list */
while (n--) {
if (!qs->next) {
qs->next = kmalloc(sizeof(struct scull_qset), GFP_KERNEL);
if (qs->next == NULL)
return NULL; /* Never mind */
memset(qs->next, 0, sizeof(struct scull_qset));
}
qs = qs->next;
continue;
}
return qs;
}
/*
* Data management: read and write
*/
ssize_t scull_read(struct file *filp, char __user *buf, size_t count,
loff_t *f_pos)
{
struct scull_dev *dev = filp->private_data;
struct scull_qset *dptr; /* the first listitem */
int quantum = dev->quantum, qset = dev->qset;
int itemsize = quantum * qset; /* how many bytes in the listitem */
int item, s_pos, q_pos, rest;
ssize_t retval = 0;
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
if (*f_pos >= dev->size)
goto out;
if (*f_pos + count > dev->size)
count = dev->size - *f_pos;
/* find listitem, qset index, and offset in the quantum */
item = (long)*f_pos / itemsize;
rest = (long)*f_pos % itemsize;
s_pos = rest / quantum; q_pos = rest % quantum;
/* follow the list up to the right position (defined elsewhere) */
dptr = scull_follow(dev, item);
if (dptr == NULL || !dptr->data || ! dptr->data[s_pos])
goto out; /* don't fill holes */
/* read only up to the end of this quantum */
if (count > quantum - q_pos)
count = quantum - q_pos;
if (copy_to_user(buf, dptr->data[s_pos] + q_pos, count)) {
retval = -EFAULT;
goto out;
}
*f_pos += count;
retval = count;
out:
up(&dev->sem);
return retval;
}
ssize_t scull_write(struct file *filp, const char __user *buf, size_t count,
loff_t *f_pos)
{
struct scull_dev *dev = filp->private_data;
struct scull_qset *dptr;
int quantum = dev->quantum, qset = dev->qset;
int itemsize = quantum * qset;
int item, s_pos, q_pos, rest;
ssize_t retval = -ENOMEM; /* value used in "goto out" statements */
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
/* find listitem, qset index and offset in the quantum */
item = (long)*f_pos / itemsize;
rest = (long)*f_pos % itemsize;
s_pos = rest / quantum; q_pos = rest % quantum;
/* follow the list up to the right position */
dptr = scull_follow(dev, item);
if (dptr == NULL)
goto out;
if (!dptr->data) {
dptr->data = kmalloc(qset * sizeof(char *), GFP_KERNEL);
if (!dptr->data)
goto out;
memset(dptr->data, 0, qset * sizeof(char *));
}
if (!dptr->data[s_pos]) {
dptr->data[s_pos] = kmalloc(quantum, GFP_KERNEL);
if (!dptr->data[s_pos])
goto out;
}
/* write only up to the end of this quantum */
if (count > quantum - q_pos)
count = quantum - q_pos;
if (copy_from_user(dptr->data[s_pos]+q_pos, buf, count)) {
retval = -EFAULT;
goto out;
}
*f_pos += count;
retval = count;
/* update the size */
if (dev->size < *f_pos)
dev->size = *f_pos;
out:
up(&dev->sem);
return retval;
}
/*
* The ioctl() implementation
*/
long scull_ioctl(struct file *filp,
unsigned int cmd, unsigned long arg)
{
int err = 0, tmp;
int retval = 0;
/*
* extract the type and number bitfields, and don't decode
* wrong cmds: return ENOTTY (inappropriate ioctl) before access_ok()
*/
if (_IOC_TYPE(cmd) != SCULL_IOC_MAGIC) return -ENOTTY;
if (_IOC_NR(cmd) > SCULL_IOC_MAXNR) return -ENOTTY;
/*
* the direction is a bitmask, and VERIFY_WRITE catches R/W
* transfers. `Type' is user-oriented, while
* access_ok is kernel-oriented, so the concept of "read" and
* "write" is reversed
*/
if (_IOC_DIR(cmd) & _IOC_READ)
err = !access_ok(VERIFY_WRITE, (void __user *)arg, _IOC_SIZE(cmd));
else if (_IOC_DIR(cmd) & _IOC_WRITE)
err = !access_ok(VERIFY_READ, (void __user *)arg, _IOC_SIZE(cmd));
if (err) return -EFAULT;
switch(cmd) {
case SCULL_IOCRESET:
scull_quantum = SCULL_QUANTUM;
scull_qset = SCULL_QSET;
break;
case SCULL_IOCSQUANTUM: /* Set: arg points to the value */
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
retval = __get_user(scull_quantum, (int __user *)arg);
break;
case SCULL_IOCTQUANTUM: /* Tell: arg is the value */
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
scull_quantum = arg;
break;
case SCULL_IOCGQUANTUM: /* Get: arg is pointer to result */
retval = __put_user(scull_quantum, (int __user *)arg);
break;
case SCULL_IOCQQUANTUM: /* Query: return it (it's positive) */
return scull_quantum;
case SCULL_IOCXQUANTUM: /* eXchange: use arg as pointer */
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
tmp = scull_quantum;
retval = __get_user(scull_quantum, (int __user *)arg);
if (retval == 0)
retval = __put_user(tmp, (int __user *)arg);
break;
case SCULL_IOCHQUANTUM: /* sHift: like Tell + Query */
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
tmp = scull_quantum;
scull_quantum = arg;
return tmp;
case SCULL_IOCSQSET:
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
retval = __get_user(scull_qset, (int __user *)arg);
break;
case SCULL_IOCTQSET:
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
scull_qset = arg;
break;
case SCULL_IOCGQSET:
retval = __put_user(scull_qset, (int __user *)arg);
break;
case SCULL_IOCQQSET:
return scull_qset;
case SCULL_IOCXQSET:
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
tmp = scull_qset;
retval = __get_user(scull_qset, (int __user *)arg);
if (retval == 0)
retval = put_user(tmp, (int __user *)arg);
break;
case SCULL_IOCHQSET:
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
tmp = scull_qset;
scull_qset = arg;
return tmp;
/*
* The following two change the buffer size for scullpipe.
* The scullpipe device uses this same ioctl method, just to
* write less code. Actually, it's the same driver, isn't it?
*/
case SCULL_P_IOCTSIZE:
scull_p_buffer = arg;
break;
case SCULL_P_IOCQSIZE:
return scull_p_buffer;
default: /* redundant, as cmd was checked against MAXNR */
return -ENOTTY;
}
return retval;
}
/*
* The "extended" operations -- only seek
*/
loff_t scull_llseek(struct file *filp, loff_t off, int whence)
{
struct scull_dev *dev = filp->private_data;
loff_t newpos;
switch(whence) {
case 0: /* SEEK_SET */
newpos = off;
break;
case 1: /* SEEK_CUR */
newpos = filp->f_pos + off;
break;
case 2: /* SEEK_END */
newpos = dev->size + off;
break;
default: /* can't happen */
return -EINVAL;
}
if (newpos < 0) return -EINVAL;
filp->f_pos = newpos;
return newpos;
}
struct file_operations scull_fops = {
.owner = THIS_MODULE,
.llseek = scull_llseek,
.read = scull_read,
.write = scull_write,
.unlocked_ioctl = scull_ioctl,
.compat_ioctl = scull_ioctl,
.open = scull_open,
.release = scull_release,
};
/*
* Finally, the module stuff
*/
/*
* The cleanup function is used to handle initialization failures as well.
* Thefore, it must be careful to work correctly even if some of the items
* have not been initialized
*/
void scull_cleanup_module(void)
{
int i;
dev_t devno = MKDEV(scull_major, scull_minor);
/* Get rid of our char dev entries */
if (scull_devices) {
for (i = 0; i < scull_nr_devs; i++) {
scull_trim(scull_devices + i);
device_destroy(scull_class, scull_devices[i].devno);
cdev_del(&scull_devices[i].cdev);
}
kfree(scull_devices);
}
#ifdef SCULL_DEBUG /* use proc only if debugging */
scull_remove_proc();
#endif
/* cleanup_module is never called if registering failed */
unregister_chrdev_region(devno, scull_nr_devs);
/* and call the cleanup functions for friend devices */
scull_p_cleanup();
scull_access_cleanup();
class_destroy(scull_class);
}
/*
* Set up the char_dev structure for this device.
*/
static void scull_setup_cdev(struct scull_dev *dev, int index)
{
int err;
dev->devno = MKDEV(scull_major, scull_minor + index);
cdev_init(&dev->cdev, &scull_fops);
dev->cdev.owner = THIS_MODULE;
dev->cdev.ops = &scull_fops;
err = cdev_add (&dev->cdev, dev->devno, 1);
/* Fail gracefully if need be */
if (err) {
printk(KERN_NOTICE "Error %d adding scull%d", err, index);
return;
}
dev->dev = device_create(scull_class, 0, dev->devno, 0, "scull%d", index);
if (IS_ERR(dev->dev)) {
printk(KERN_NOTICE "Error %ld adding scull%d to sysfs", PTR_ERR(dev->dev), index);
dev->dev = 0;
}
}
int scull_init_module(void)
{
int result, i;
dev_t dev = 0;
/*
* Get a range of minor numbers to work with, asking for a dynamic
* major unless directed otherwise at load time.
*/
if (scull_major) {
dev = MKDEV(scull_major, scull_minor);
result = register_chrdev_region(dev, scull_nr_devs, "scull");
} else {
result = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs,
"scull");
scull_major = MAJOR(dev);
}
if (result < 0) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return result;
}
scull_class = class_create(THIS_MODULE, "scull");
if (IS_ERR(scull_class)) {
result = PTR_ERR(scull_class);
goto fail;
}
/*
* allocate the devices -- we can't have them static, as the number
* can be specified at load time
*/
scull_devices = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_devices) {
result = -ENOMEM;
goto fail; /* Make this more graceful */
}
memset(scull_devices, 0, scull_nr_devs * sizeof(struct scull_dev));
/* Initialize each device. */
for (i = 0; i < scull_nr_devs; i++) {
scull_devices[i].quantum = scull_quantum;
scull_devices[i].qset = scull_qset;
sema_init(&scull_devices[i].sem, 1);
scull_setup_cdev(&scull_devices[i], i);
}
/* At this point call the init function for any friend device */
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
dev += scull_p_init(dev);
dev += scull_access_init(dev);
#ifdef SCULL_DEBUG /* only when debugging */
scull_create_proc();
#endif
return 0; /* succeed */
fail:
scull_cleanup_module();
return result;
}
module_init(scull_init_module);
module_exit(scull_cleanup_module);
p1_scull/pipe.c0000644000175000017500000002646212126651741012076 0ustar mwkmwk/*
* pipe.c -- fifo driver for scull
*
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/kernel.h> /* printk(), min() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/fs.h> /* everything... */
#include <linux/proc_fs.h>
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>
#include "scull.h" /* local definitions */
struct scull_pipe {
wait_queue_head_t inq, outq; /* read and write queues */
char *buffer, *end; /* begin of buf, end of buf */
int buffersize; /* used in pointer arithmetic */
char *rp, *wp; /* where to read, where to write */
int nreaders, nwriters; /* number of openings for r/w */
struct fasync_struct *async_queue; /* asynchronous readers */
struct semaphore sem; /* mutual exclusion semaphore */
dev_t devno; /* Our device major+minor */
struct cdev cdev; /* Char device structure */
struct device *dev; /* Sysfs device structure */
};
/* parameters */
static int scull_p_nr_devs = SCULL_P_NR_DEVS; /* number of pipe devices */
int scull_p_buffer = SCULL_P_BUFFER; /* buffer size */
dev_t scull_p_devno; /* Our first device number */
module_param(scull_p_nr_devs, int, 0); /* FIXME check perms */
module_param(scull_p_buffer, int, 0);
static struct scull_pipe *scull_p_devices;
static int scull_p_fasync(int fd, struct file *filp, int mode);
static int spacefree(struct scull_pipe *dev);
/*
* Open and close
*/
static int scull_p_open(struct inode *inode, struct file *filp)
{
struct scull_pipe *dev;
dev = container_of(inode->i_cdev, struct scull_pipe, cdev);
filp->private_data = dev;
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
if (!dev->buffer) {
/* allocate the buffer */
dev->buffer = kmalloc(scull_p_buffer, GFP_KERNEL);
if (!dev->buffer) {
up(&dev->sem);
return -ENOMEM;
}
}
dev->buffersize = scull_p_buffer;
dev->end = dev->buffer + dev->buffersize;
dev->rp = dev->wp = dev->buffer; /* rd and wr from the beginning */
/* use f_mode,not f_flags: it's cleaner (fs/open.c tells why) */
if (filp->f_mode & FMODE_READ)
dev->nreaders++;
if (filp->f_mode & FMODE_WRITE)
dev->nwriters++;
up(&dev->sem);
return nonseekable_open(inode, filp);
}
static int scull_p_release(struct inode *inode, struct file *filp)
{
struct scull_pipe *dev = filp->private_data;
/* remove this filp from the asynchronously notified filp's */
scull_p_fasync(-1, filp, 0);
down(&dev->sem);
if (filp->f_mode & FMODE_READ)
dev->nreaders--;
if (filp->f_mode & FMODE_WRITE)
dev->nwriters--;
if (dev->nreaders + dev->nwriters == 0) {
kfree(dev->buffer);
dev->buffer = NULL; /* the other fields are not checked on open */
}
up(&dev->sem);
return 0;
}
/*
* Data management: read and write
*/
static ssize_t scull_p_read (struct file *filp, char __user *buf, size_t count,
loff_t *f_pos)
{
struct scull_pipe *dev = filp->private_data;
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
while (dev->rp == dev->wp) { /* nothing to read */
up(&dev->sem); /* release the lock */
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
PDEBUG("\"%s\" reading: going to sleep\n", current->comm);
if (wait_event_interruptible(dev->inq, (dev->rp != dev->wp)))
return -ERESTARTSYS; /* signal: tell the fs layer to handle it */
/* otherwise loop, but first reacquire the lock */
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
}
/* ok, data is there, return something */
if (dev->wp > dev->rp)
count = min(count, (size_t)(dev->wp - dev->rp));
else /* the write pointer has wrapped, return data up to dev->end */
count = min(count, (size_t)(dev->end - dev->rp));
if (copy_to_user(buf, dev->rp, count)) {
up (&dev->sem);
return -EFAULT;
}
dev->rp += count;
if (dev->rp == dev->end)
dev->rp = dev->buffer; /* wrapped */
up (&dev->sem);
/* finally, awake any writers and return */
wake_up_interruptible(&dev->outq);
PDEBUG("\"%s\" did read %li bytes\n",current->comm, (long)count);
return count;
}
/* Wait for space for writing; caller must hold device semaphore. On
* error the semaphore will be released before returning. */
static int scull_getwritespace(struct scull_pipe *dev, struct file *filp)
{
while (spacefree(dev) == 0) { /* full */
DEFINE_WAIT(wait);
up(&dev->sem);
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
PDEBUG("\"%s\" writing: going to sleep\n",current->comm);
prepare_to_wait(&dev->outq, &wait, TASK_INTERRUPTIBLE);
if (spacefree(dev) == 0)
schedule();
finish_wait(&dev->outq, &wait);
if (signal_pending(current))
return -ERESTARTSYS; /* signal: tell the fs layer to handle it */
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
}
return 0;
}
/* How much space is free? */
static int spacefree(struct scull_pipe *dev)
{
if (dev->rp == dev->wp)
return dev->buffersize - 1;
return ((dev->rp + dev->buffersize - dev->wp) % dev->buffersize) - 1;
}
static ssize_t scull_p_write(struct file *filp, const char __user *buf, size_t count,
loff_t *f_pos)
{
struct scull_pipe *dev = filp->private_data;
int result;
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
/* Make sure there's space to write */
result = scull_getwritespace(dev, filp);
if (result)
return result; /* scull_getwritespace called up(&dev->sem) */
/* ok, space is there, accept something */
count = min(count, (size_t)spacefree(dev));
if (dev->wp >= dev->rp)
count = min(count, (size_t)(dev->end - dev->wp)); /* to end-of-buf */
else /* the write pointer has wrapped, fill up to rp-1 */
count = min(count, (size_t)(dev->rp - dev->wp - 1));
PDEBUG("Going to accept %li bytes to %p from %p\n", (long)count, dev->wp, buf);
if (copy_from_user(dev->wp, buf, count)) {
up (&dev->sem);
return -EFAULT;
}
dev->wp += count;
if (dev->wp == dev->end)
dev->wp = dev->buffer; /* wrapped */
up(&dev->sem);
/* finally, awake any reader */
wake_up_interruptible(&dev->inq); /* blocked in read() and select() */
/* and signal asynchronous readers, explained late in chapter 5 */
if (dev->async_queue)
kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
PDEBUG("\"%s\" did write %li bytes\n",current->comm, (long)count);
return count;
}
static unsigned int scull_p_poll(struct file *filp, poll_table *wait)
{
struct scull_pipe *dev = filp->private_data;
unsigned int mask = 0;
/*
* The buffer is circular; it is considered full
* if "wp" is right behind "rp" and empty if the
* two are equal.
*/
down(&dev->sem);
poll_wait(filp, &dev->inq, wait);
poll_wait(filp, &dev->outq, wait);
if (dev->rp != dev->wp)
mask |= POLLIN | POLLRDNORM; /* readable */
if (spacefree(dev))
mask |= POLLOUT | POLLWRNORM; /* writable */
up(&dev->sem);
return mask;
}
static int scull_p_fasync(int fd, struct file *filp, int mode)
{
struct scull_pipe *dev = filp->private_data;
return fasync_helper(fd, filp, mode, &dev->async_queue);
}
/* FIXME this should use seq_file */
#ifdef SCULL_DEBUG
static void scullp_proc_offset(char *buf, char **start, off_t *offset, int *len)
{
if (*offset == 0)
return;
if (*offset >= *len) { /* Not there yet */
*offset -= *len;
*len = 0;
}
else { /* We're into the interesting stuff now */
*start = buf + *offset;
*offset = 0;
}
}
static int scull_read_p_mem(char *buf, char **start, off_t offset, int count,
int *eof, void *data)
{
int i, len;
struct scull_pipe *p;
#define LIMIT (PAGE_SIZE-200) /* don't print any more after this size */
*start = buf;
len = sprintf(buf, "Default buffersize is %i\n", scull_p_buffer);
for(i = 0; i<scull_p_nr_devs && len <= LIMIT; i++) {
p = &scull_p_devices[i];
if (down_interruptible(&p->sem))
return -ERESTARTSYS;
len += sprintf(buf+len, "\nDevice %i: %p\n", i, p);
/* len += sprintf(buf+len, " Queues: %p %p\n", p->inq, p->outq);*/
len += sprintf(buf+len, " Buffer: %p to %p (%i bytes)\n", p->buffer, p->end, p->buffersize);
len += sprintf(buf+len, " rp %p wp %p\n", p->rp, p->wp);
len += sprintf(buf+len, " readers %i writers %i\n", p->nreaders, p->nwriters);
up(&p->sem);
scullp_proc_offset(buf, start, &offset, &len);
}
*eof = (len <= LIMIT);
return len;
}
#endif
/*
* The file operations for the pipe device
* (some are overlayed with bare scull)
*/
struct file_operations scull_pipe_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = scull_p_read,
.write = scull_p_write,
.poll = scull_p_poll,
.unlocked_ioctl = scull_ioctl,
.open = scull_p_open,
.release = scull_p_release,
.fasync = scull_p_fasync,
};
/*
* Set up a cdev entry.
*/
static void scull_p_setup_cdev(struct scull_pipe *dev, int index)
{
int err;
dev->devno = scull_p_devno + index;
cdev_init(&dev->cdev, &scull_pipe_fops);
dev->cdev.owner = THIS_MODULE;
err = cdev_add (&dev->cdev, dev->devno, 1);
/* Fail gracefully if need be */
if (err) {
printk(KERN_NOTICE "Error %d adding scullpipe%d", err, index);
return;
}
dev->dev = device_create(scull_class, 0, dev->devno, 0, "scullpipe%d", index);
if (IS_ERR(dev->dev)) {
printk(KERN_NOTICE "Error %ld adding scullpipe%d to sysfs", PTR_ERR(dev->dev), index);
dev->dev = 0;
}
}
/*
* Initialize the pipe devs; return how many we did.
*/
int scull_p_init(dev_t firstdev)
{
int i, result;
result = register_chrdev_region(firstdev, scull_p_nr_devs, "scullp");
if (result < 0) {
printk(KERN_NOTICE "Unable to get scullp region, error %d\n", result);
return 0;
}
scull_p_devno = firstdev;
scull_p_devices = kmalloc(scull_p_nr_devs * sizeof(struct scull_pipe), GFP_KERNEL);
if (scull_p_devices == NULL) {
unregister_chrdev_region(firstdev, scull_p_nr_devs);
return 0;
}
memset(scull_p_devices, 0, scull_p_nr_devs * sizeof(struct scull_pipe));
for (i = 0; i < scull_p_nr_devs; i++) {
init_waitqueue_head(&(scull_p_devices[i].inq));
init_waitqueue_head(&(scull_p_devices[i].outq));
sema_init(&scull_p_devices[i].sem, 1);
scull_p_setup_cdev(scull_p_devices + i, i);
}
#ifdef SCULL_DEBUG
create_proc_read_entry("scullpipe", 0, NULL, scull_read_p_mem, NULL);
#endif
return scull_p_nr_devs;
}
/*
* This is called by cleanup_module or on failure.
* It is required to never fail, even if nothing was initialized first
*/
void scull_p_cleanup(void)
{
int i;
#ifdef SCULL_DEBUG
remove_proc_entry("scullpipe", NULL);
#endif
if (!scull_p_devices)
return; /* nothing else to release */
for (i = 0; i < scull_p_nr_devs; i++) {
device_destroy(scull_class, scull_p_devices[i].devno);
cdev_del(&scull_p_devices[i].cdev);
kfree(scull_p_devices[i].buffer);
}
kfree(scull_p_devices);
unregister_chrdev_region(scull_p_devno, scull_p_nr_devs);
scull_p_devices = NULL; /* pedantic */
}
p1_scull/scull.mod.c0000664000175000017500000000564112312246527013036 0ustar mwkmwk#include <linux/module.h>
#include <linux/vermagic.h>
#include <linux/compiler.h>
MODULE_INFO(vermagic, VERMAGIC_STRING);
__visible struct module __this_module
__attribute__((section(".gnu.linkonce.this_module"))) = {
.name = KBUILD_MODNAME,
.init = init_module,
#ifdef CONFIG_MODULE_UNLOAD
.exit = cleanup_module,
#endif
.arch = MODULE_ARCH_INIT,
};
static const struct modversion_info ____versions[]
__used
__attribute__((section("__versions"))) = {
{ 0x10e8aa74, __VMLINUX_SYMBOL_STR(module_layout) },
{ 0x209274d7, __VMLINUX_SYMBOL_STR(kobject_put) },
{ 0x165e0753, __VMLINUX_SYMBOL_STR(cdev_del) },
{ 0x1cf5f225, __VMLINUX_SYMBOL_STR(kmalloc_caches) },
{ 0xd2b09ce5, __VMLINUX_SYMBOL_STR(__kmalloc) },
{ 0x3fdfc3b5, __VMLINUX_SYMBOL_STR(cdev_init) },
{ 0x4c4fef19, __VMLINUX_SYMBOL_STR(kernel_stack) },
{ 0x68e2f221, __VMLINUX_SYMBOL_STR(_raw_spin_unlock) },
{ 0xb6b46a7c, __VMLINUX_SYMBOL_STR(param_ops_int) },
{ 0xd8e484f0, __VMLINUX_SYMBOL_STR(register_chrdev_region) },
{ 0xc8b57c27, __VMLINUX_SYMBOL_STR(autoremove_wake_function) },
{ 0x32fd4b62, __VMLINUX_SYMBOL_STR(__wake_up_sync) },
{ 0x734e6b5e, __VMLINUX_SYMBOL_STR(no_llseek) },
{ 0x4792c572, __VMLINUX_SYMBOL_STR(down_interruptible) },
{ 0x2765cefd, __VMLINUX_SYMBOL_STR(device_destroy) },
{ 0xa5ecf5b1, __VMLINUX_SYMBOL_STR(kobject_set_name) },
{ 0x7485e15e, __VMLINUX_SYMBOL_STR(unregister_chrdev_region) },
{ 0x43582835, __VMLINUX_SYMBOL_STR(tty_devnum) },
{ 0x38464750, __VMLINUX_SYMBOL_STR(nonseekable_open) },
{ 0x68dfc59f, __VMLINUX_SYMBOL_STR(__init_waitqueue_head) },
{ 0x4f8b5ddb, __VMLINUX_SYMBOL_STR(_copy_to_user) },
{ 0xfb578fc5, __VMLINUX_SYMBOL_STR(memset) },
{ 0xfc91eaa1, __VMLINUX_SYMBOL_STR(current_task) },
{ 0x27e1a049, __VMLINUX_SYMBOL_STR(printk) },
{ 0x9ab65d65, __VMLINUX_SYMBOL_STR(fasync_helper) },
{ 0xdd1a2871, __VMLINUX_SYMBOL_STR(down) },
{ 0x1bf161fb, __VMLINUX_SYMBOL_STR(device_create) },
{ 0xc7194128, __VMLINUX_SYMBOL_STR(cdev_add) },
{ 0xc6cbbc89, __VMLINUX_SYMBOL_STR(capable) },
{ 0xb2fd5ceb, __VMLINUX_SYMBOL_STR(__put_user_4) },
{ 0x1000e51, __VMLINUX_SYMBOL_STR(schedule) },
{ 0xbdfb6dbb, __VMLINUX_SYMBOL_STR(__fentry__) },
{ 0xfcfc4beb, __VMLINUX_SYMBOL_STR(kmem_cache_alloc_trace) },
{ 0x67f7403e, __VMLINUX_SYMBOL_STR(_raw_spin_lock) },
{ 0xe45f60d8, __VMLINUX_SYMBOL_STR(__wake_up) },
{ 0xa56d356, __VMLINUX_SYMBOL_STR(prepare_to_wait_event) },
{ 0x37a0cba, __VMLINUX_SYMBOL_STR(kfree) },
{ 0x622fa02a, __VMLINUX_SYMBOL_STR(prepare_to_wait) },
{ 0xc4554217, __VMLINUX_SYMBOL_STR(up) },
{ 0x6bd67414, __VMLINUX_SYMBOL_STR(class_destroy) },
{ 0x45e06d7e, __VMLINUX_SYMBOL_STR(kill_fasync) },
{ 0x75bb675a, __VMLINUX_SYMBOL_STR(finish_wait) },
{ 0x4f6b400b, __VMLINUX_SYMBOL_STR(_copy_from_user) },
{ 0x39d28619, __VMLINUX_SYMBOL_STR(__class_create) },
{ 0x29537c9e, __VMLINUX_SYMBOL_STR(alloc_chrdev_region) },
};
static const char __module_depends[]
__used
__attribute__((section(".modinfo"))) =
"depends=";
p1_scull/Kbuild0000644000175000017500000000007012126651741012115 0ustar mwkmwkscull-objs := main.o pipe.o access.o
obj-m := scull.o
p1_scull/Makefile0000644000175000017500000000025412126651741012424 0ustar mwkmwkKDIR ?= /lib/modules/`uname -r`/build
default:
$(MAKE) -C $(KDIR) M=$$PWD
install:
$(MAKE) -C $(KDIR) M=$$PWD modules_install
clean:
$(MAKE) -C $(KDIR) M=$$PWD clean