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