xenstored.c

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#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/fs.h>

#include <xen/page.h>

#include "xenfs.h"
#include "../xenbus/xenbus_comms.h"

static ssize_t xsd_read(struct file *file, char __user *buf,
                size_t size, loff_t *off)
{
    const char *str = (const char *)file->private_data;
    return simple_read_from_buffer(buf, size, off, str, strlen(str));
}

static int xsd_release(struct inode *inode, struct file *file)
{
    kfree(file->private_data);
    return 0;
}

static int xsd_kva_open(struct inode *inode, struct file *file)
{
    file->private_data = (void *)kasprintf(GFP_KERNEL, "0x%p",
                           xen_store_interface);
    if (!file->private_data)
        return -ENOMEM;
    return 0;
}

static int xsd_kva_mmap(struct file *file, struct vm_area_struct *vma)
{
    size_t size = vma->vm_end - vma->vm_start;

    if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
        return -EINVAL;

    if (remap_pfn_range(vma, vma->vm_start,
                virt_to_pfn(xen_store_interface),
                size, vma->vm_page_prot))
        return -EAGAIN;

    return 0;
}

const struct file_operations xsd_kva_file_ops = {
    .open = xsd_kva_open,
    .mmap = xsd_kva_mmap,
    .read = xsd_read,
    .release = xsd_release,
};

static int xsd_port_open(struct inode *inode, struct file *file)
{
    file->private_data = (void *)kasprintf(GFP_KERNEL, "%d",
                           xen_store_evtchn);
    if (!file->private_data)
        return -ENOMEM;
    return 0;
}

const struct file_operations xsd_port_file_ops = {
    .open = xsd_port_open,
    .read = xsd_read,
    .release = xsd_release,
};