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// SPDX-License-Identifier: GPL-2.0-only
/*
* xenfs.c - a filesystem for passing info between the a domain and
* the hypervisor.
*
* 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem
* and /proc/xen compatibility mount point.
* Turned xenfs into a loadable module.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/fs_context.h>
#include <linux/magic.h>
#include <xen/xen.h>
#include <xen/xenbus.h>
#include "xenfs.h"
#include "../privcmd.h"
#include <asm/xen/hypervisor.h>
MODULE_DESCRIPTION("Xen filesystem");
MODULE_LICENSE("GPL");
static ssize_t capabilities_read(struct file *file, char __user *buf,
size_t size, loff_t *off)
{
char *tmp = "";
if (xen_initial_domain())
tmp = "control_d\n";
return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp));
}
static const struct file_operations capabilities_file_ops = {
.read = capabilities_read,
.llseek = default_llseek,
};
static int xenfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
static const struct tree_descr xenfs_files[] = {
[2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
{ "capabilities", &capabilities_file_ops, S_IRUGO },
{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
{""},
};
static const struct tree_descr xenfs_init_files[] = {
[2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
{ "capabilities", &capabilities_file_ops, S_IRUGO },
{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
{ "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR},
{ "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR},
#ifdef CONFIG_XEN_SYMS
{ "xensyms", &xensyms_ops, S_IRUSR},
#endif
{""},
};
return simple_fill_super(sb, XENFS_SUPER_MAGIC,
xen_initial_domain() ? xenfs_init_files : xenfs_files);
}
static int xenfs_get_tree(struct fs_context *fc)
{
return get_tree_single(fc, xenfs_fill_super);
}
static const struct fs_context_operations xenfs_context_ops = {
.get_tree = xenfs_get_tree,
};
static int xenfs_init_fs_context(struct fs_context *fc)
{
fc->ops = &xenfs_context_ops;
return 0;
}
static struct file_system_type xenfs_type = {
.owner = THIS_MODULE,
.name = "xenfs",
.init_fs_context = xenfs_init_fs_context,
.kill_sb = kill_litter_super,
};
MODULE_ALIAS_FS("xenfs");
static int __init xenfs_init(void)
{
if (xen_domain())
return register_filesystem(&xenfs_type);
return 0;
}
static void __exit xenfs_exit(void)
{
if (xen_domain())
unregister_filesystem(&xenfs_type);
}
module_init(xenfs_init);
module_exit(xenfs_exit);
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