mpv/libdha/kernelhelper/dhahelper.c

362 lines
8.1 KiB
C

/*
Direct Hardware Access kernel helper
(C) 2002 Alex Beregszaszi <alex@naxine.org>
Accessing hardware from userspace as USER (no root needed!)
Tested on 2.2.x (2.2.19) and 2.4.x (2.4.3,2.4.17).
License: GPL
WARNING! THIS MODULE VIOLATES SEVERAL SECURITY LINES! DON'T USE IT
ON PRODUCTION SYSTEMS, ONLY AT HOME, ON A "SINGLE-USER" SYSTEM.
NO WARRANTY!
Tech:
Communication between userspace and kernelspace goes over character
device using ioctl.
Usage:
mknod -m 666 /dev/dhahelper c 180 0
Also you can change the major number, setting the "dhahelper_major"
module parameter, the default is 180, specified in dhahelper.h.
Note: do not use other than minor==0, the module forbids it.
TODO:
* do memory mapping without fops:mmap
* implement unmap memory
* select (request?) a "valid" major number (from Linux project? ;)
* make security
* is pci handling needed? (libdha does this with lowlevel port funcs)
* is mttr handling needed?
* test on older kernels (2.0.x (?))
*/
#ifndef MODULE
#define MODULE
#endif
#ifndef __KERNEL__
#define __KERNEL__
#endif
#include <linux/config.h>
#ifdef CONFIG_MODVERSION
#define MODVERSION
#include <linux/modversions.h>
#endif
#include <linux/version.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,10)
#include <linux/malloc.h>
#else
#include <linux/slab.h>
#endif
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <linux/mman.h>
#include <linux/fs.h>
#include <linux/unistd.h>
#include "dhahelper.h"
MODULE_AUTHOR("Alex Beregszaszi <alex@naxine.org>");
MODULE_DESCRIPTION("Provides userspace access to hardware (security violation!)");
#ifdef MODULE_LICENSE
MODULE_LICENSE("GPL");
#endif
static int dhahelper_major = DEFAULT_MAJOR;
MODULE_PARM(dhahelper_major, "i");
MODULE_PARM_DESC(dhahelper_major, "Major number of dhahelper characterdevice");
/* 0 = silent */
/* 1 = report errors (default) */
/* 2 = debug */
static int dhahelper_verbosity = 1;
MODULE_PARM(dhahelper_verbosity, "i");
MODULE_PARM_DESC(dhahelper_verbosity, "Level of verbosity (0 = silent, 1 = only errors, 2 = debug)");
static dhahelper_memory_t last_mem_request;
static int dhahelper_open(struct inode *inode, struct file *file)
{
if (dhahelper_verbosity > 1)
printk(KERN_DEBUG "dhahelper: device opened\n");
if (MINOR(inode->i_rdev) != 0)
return(-ENXIO);
MOD_INC_USE_COUNT;
return(0);
}
static int dhahelper_release(struct inode *inode, struct file *file)
{
if (dhahelper_verbosity > 1)
printk(KERN_DEBUG "dhahelper: device released\n");
if (MINOR(inode->i_rdev) != 0)
return(-ENXIO);
MOD_DEC_USE_COUNT;
return(0);
}
static int dhahelper_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
if (dhahelper_verbosity > 1)
printk(KERN_DEBUG "dhahelper: ioctl(cmd=%x, arg=%lx)\n",
cmd, arg);
if (MINOR(inode->i_rdev) != 0)
return(-ENXIO);
switch(cmd)
{
case DHAHELPER_GET_VERSION:
{
int version = API_VERSION;
if (copy_to_user((int *)arg, &version, sizeof(int)))
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: failed copy to userspace\n");
return(-EFAULT);
}
break;
}
case DHAHELPER_PORT:
{
dhahelper_port_t port;
if (copy_from_user(&port, (dhahelper_port_t *)arg, sizeof(dhahelper_port_t)))
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: failed copy from userspace\n");
return(-EFAULT);
}
switch(port.operation)
{
case PORT_OP_READ:
{
switch(port.size)
{
case 1:
port.value = inb(port.addr);
break;
case 2:
port.value = inw(port.addr);
break;
case 4:
port.value = inl(port.addr);
break;
default:
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: invalid port read size (%d)\n",
port.size);
return(-EINVAL);
}
break;
}
case PORT_OP_WRITE:
{
switch(port.size)
{
case 1:
outb(port.value, port.addr);
break;
case 2:
outw(port.value, port.addr);
break;
case 4:
outl(port.value, port.addr);
break;
default:
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: invalid port write size (%d)\n",
port.size);
return(-EINVAL);
}
break;
}
default:
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: invalid port operation (%d)\n",
port.operation);
return(-EINVAL);
}
/* copy back only if read was performed */
if (port.operation == PORT_OP_READ)
if (copy_to_user((dhahelper_port_t *)arg, &port, sizeof(dhahelper_port_t)))
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: failed copy to userspace\n");
return(-EFAULT);
}
break;
}
case DHAHELPER_MEMORY:
{
dhahelper_memory_t mem;
if (copy_from_user(&mem, (dhahelper_memory_t *)arg, sizeof(dhahelper_memory_t)))
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: failed copy from userspace\n");
return(-EFAULT);
}
switch(mem.operation)
{
case MEMORY_OP_MAP:
{
#if 1
memcpy(&last_mem_request, &mem, sizeof(dhahelper_memory_t));
#else
mem.ret = do_mmap(file, mem.start, mem.size, PROT_READ|PROT_WRITE,
MAP_SHARED, mem.offset);
#endif
break;
}
case MEMORY_OP_UNMAP:
break;
default:
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: invalid memory operation (%d)\n",
mem.operation);
return(-EINVAL);
}
if (copy_to_user((dhahelper_memory_t *)arg, &mem, sizeof(dhahelper_memory_t)))
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: failed copy to userspace\n");
return(-EFAULT);
}
break;
}
default:
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: invalid ioctl (%x)\n", cmd);
return(-EINVAL);
}
return(0);
}
static int dhahelper_mmap(struct file *file, struct vm_area_struct *vma)
{
if (last_mem_request.operation != MEMORY_OP_MAP)
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: mapping not requested before mmap\n");
return(-EFAULT);
}
if (dhahelper_verbosity > 1)
printk(KERN_INFO "dhahelper: mapping %x (size: %x)\n",
last_mem_request.start+last_mem_request.offset, last_mem_request.size);
if (remap_page_range(0, last_mem_request.start + last_mem_request.offset,
last_mem_request.size, vma->vm_page_prot))
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: error mapping memory\n");
return(-EFAULT);
}
return(0);
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,0)
static struct file_operations dhahelper_fops =
{
/*llseek*/ NULL,
/*read*/ NULL,
/*write*/ NULL,
/*readdir*/ NULL,
/*poll*/ NULL,
/*ioctl*/ dhahelper_ioctl,
/*mmap*/ dhahelper_mmap,
/*open*/ dhahelper_open,
/*flush*/ NULL,
/*release*/ dhahelper_release,
/* zero out the last 5 entries too ? */
};
#else
static struct file_operations dhahelper_fops =
{
owner: THIS_MODULE,
ioctl: dhahelper_ioctl,
mmap: dhahelper_mmap,
open: dhahelper_open,
release: dhahelper_release
};
#endif
#if KERNEL_VERSION < KERNEL_VERSION(2,4,0)
int init_module(void)
#else
static int __init init_dhahelper(void)
#endif
{
printk(KERN_INFO "Direct Hardware Access kernel helper (C) Alex Beregszaszi\n");
if(register_chrdev(dhahelper_major, "dhahelper", &dhahelper_fops))
{
if (dhahelper_verbosity > 0)
printk(KERN_ERR "dhahelper: unable to register character device (major: %d)\n",
dhahelper_major);
return(-EIO);
}
return(0);
}
#if KERNEL_VERSION < KERNEL_VERSION(2,4,0)
void cleanup_module(void)
#else
static void __exit exit_dhahelper(void)
#endif
{
unregister_chrdev(dhahelper_major, "dhahelper");
}
EXPORT_NO_SYMBOLS;
#if KERNEL_VERSION >= KERNEL_VERSION(2,4,0)
module_init(init_dhahelper);
module_exit(exit_dhahelper);
#endif