xenbus_dev_backend.c revision e9f0fec3f5d406c500861da779d16a779a110055
1e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <linux/slab.h> 2e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <linux/types.h> 3e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <linux/mm.h> 4e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <linux/fs.h> 5e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <linux/miscdevice.h> 6e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <linux/module.h> 7e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <linux/capability.h> 8e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 9e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <xen/page.h> 10e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include <xen/xenbus_dev.h> 11e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 12e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank#include "xenbus_comms.h" 13e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 14e9f0fec3f5d406c500861da779d16a779a110055Bastian BlankMODULE_LICENSE("GPL"); 15e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 16e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankstatic int xenbus_backend_open(struct inode *inode, struct file *filp) 17e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank{ 18e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if (!capable(CAP_SYS_ADMIN)) 19e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -EPERM; 20e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 21e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return nonseekable_open(inode, filp); 22e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank} 23e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 24e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankstatic long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned long data) 25e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank{ 26e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if (!capable(CAP_SYS_ADMIN)) 27e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -EPERM; 28e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 29e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank switch (cmd) { 30e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank case IOCTL_XENBUS_BACKEND_EVTCHN: 31e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if (xen_store_evtchn > 0) 32e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return xen_store_evtchn; 33e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -ENODEV; 34e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 35e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank default: 36e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -ENOTTY; 37e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank } 38e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank} 39e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 40e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankstatic int xenbus_backend_mmap(struct file *file, struct vm_area_struct *vma) 41e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank{ 42e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank size_t size = vma->vm_end - vma->vm_start; 43e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 44e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if (!capable(CAP_SYS_ADMIN)) 45e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -EPERM; 46e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 47e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0)) 48e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -EINVAL; 49e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 50e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if (remap_pfn_range(vma, vma->vm_start, 51e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank virt_to_pfn(xen_store_interface), 52e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank size, vma->vm_page_prot)) 53e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -EAGAIN; 54e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 55e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return 0; 56e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank} 57e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 58e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankconst struct file_operations xenbus_backend_fops = { 59e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank .open = xenbus_backend_open, 60e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank .mmap = xenbus_backend_mmap, 61e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank .unlocked_ioctl = xenbus_backend_ioctl, 62e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank}; 63e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 64e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankstatic struct miscdevice xenbus_backend_dev = { 65e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank .minor = MISC_DYNAMIC_MINOR, 66e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank .name = "xen/xenbus_backend", 67e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank .fops = &xenbus_backend_fops, 68e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank}; 69e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 70e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankstatic int __init xenbus_backend_init(void) 71e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank{ 72e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank int err; 73e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 74e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if (!xen_initial_domain()) 75e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return -ENODEV; 76e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 77e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank err = misc_register(&xenbus_backend_dev); 78e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank if (err) 79e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank printk(KERN_ERR "Could not register xenbus backend device\n"); 80e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank return err; 81e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank} 82e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 83e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankstatic void __exit xenbus_backend_exit(void) 84e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank{ 85e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank misc_deregister(&xenbus_backend_dev); 86e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank} 87e9f0fec3f5d406c500861da779d16a779a110055Bastian Blank 88e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankmodule_init(xenbus_backend_init); 89e9f0fec3f5d406c500861da779d16a779a110055Bastian Blankmodule_exit(xenbus_backend_exit); 90