kernel/drivers/xen/xenfs/xenstored.c

   1 #include <linux/slab.h>
   2 #include <linux/types.h>
   3 #include <linux/mm.h>
   4 #include <linux/fs.h>
   5
   6 #include <xen/page.h>
   7
   8 #include "xenfs.h"
   9 #include "../xenbus/xenbus_comms.h"
  10
  11 static ssize_t xsd_read(struct file *file, char __user *buf,
  12                             size_t size, loff_t *off)
  13 {
  14         const char *str = (const char *)file->private_data;
  15         return simple_read_from_buffer(buf, size, off, str, strlen(str));
  16 }
  17
  18 static int xsd_release(struct inode *inode, struct file *file)
  19 {
  20         kfree(file->private_data);
  21         return 0;
  22 }
  23
  24 static int xsd_kva_open(struct inode *inode, struct file *file)
  25 {
  26         file->private_data = (void *)kasprintf(GFP_KERNEL, "0x%p",
  27                                                xen_store_interface);
  28         if (!file->private_data)
  29                 return -ENOMEM;
  30         return 0;
  31 }
  32
  33 static int xsd_kva_mmap(struct file *file, struct vm_area_struct *vma)
  34 {
  35         size_t size = vma->vm_end - vma->vm_start;
  36
  37         if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
  38                 return -EINVAL;
  39
  40         if (remap_pfn_range(vma, vma->vm_start,
  41                             virt_to_pfn(xen_store_interface),
  42                             size, vma->vm_page_prot))
  43                 return -EAGAIN;
  44
  45         return 0;
  46 }
  47
  48 const struct file_operations xsd_kva_file_ops = {
  49         .open = xsd_kva_open,
  50         .mmap = xsd_kva_mmap,
  51         .read = xsd_read,
  52         .release = xsd_release,
  53 };
  54
  55 static int xsd_port_open(struct inode *inode, struct file *file)
  56 {
  57         file->private_data = (void *)kasprintf(GFP_KERNEL, "%d",
  58                                                xen_store_evtchn);
  59         if (!file->private_data)
  60                 return -ENOMEM;
  61         return 0;
  62 }
  63
  64 const struct file_operations xsd_port_file_ops = {
  65         .open = xsd_port_open,
  66         .read = xsd_read,
  67         .release = xsd_release,
  68 };