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1c5de1939c
The privcmd interface in xenfs allows the tool stack in the privileged domain to get fairly direct access to the hypervisor in order to do various management things such as domain construction. [ Impact: new xenfs interface for privileged operations ] Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
138 lines
3.0 KiB
C
138 lines
3.0 KiB
C
/*
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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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#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/magic.h>
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#include <xen/xen.h>
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#include "xenfs.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 struct inode *xenfs_make_inode(struct super_block *sb, int mode)
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{
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struct inode *ret = new_inode(sb);
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if (ret) {
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ret->i_mode = mode;
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ret->i_uid = ret->i_gid = 0;
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ret->i_blocks = 0;
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ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
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}
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return ret;
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}
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static struct dentry *xenfs_create_file(struct super_block *sb,
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struct dentry *parent,
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const char *name,
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const struct file_operations *fops,
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void *data,
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int mode)
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{
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struct dentry *dentry;
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struct inode *inode;
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dentry = d_alloc_name(parent, name);
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if (!dentry)
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return NULL;
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inode = xenfs_make_inode(sb, S_IFREG | mode);
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if (!inode) {
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dput(dentry);
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return NULL;
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}
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inode->i_fop = fops;
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inode->i_private = data;
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d_add(dentry, inode);
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return dentry;
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}
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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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};
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static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
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{
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static struct tree_descr xenfs_files[] = {
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[1] = {},
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{ "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR },
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{ "capabilities", &capabilities_file_ops, S_IRUGO },
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{""},
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};
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int rc;
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rc = simple_fill_super(sb, XENFS_SUPER_MAGIC, xenfs_files);
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if (rc < 0)
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return rc;
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if (xen_initial_domain()) {
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xenfs_create_file(sb, sb->s_root, "xsd_kva",
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&xsd_kva_file_ops, NULL, S_IRUSR|S_IWUSR);
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xenfs_create_file(sb, sb->s_root, "xsd_port",
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&xsd_port_file_ops, NULL, S_IRUSR|S_IWUSR);
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xenfs_create_file(sb, sb->s_root, "privcmd",
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&privcmd_file_ops, NULL, S_IRUSR|S_IWUSR);
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}
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return rc;
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}
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static int xenfs_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name,
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void *data, struct vfsmount *mnt)
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{
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return get_sb_single(fs_type, flags, data, xenfs_fill_super, mnt);
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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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.get_sb = xenfs_get_sb,
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.kill_sb = kill_litter_super,
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};
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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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printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n");
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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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