1 #include <linux/module.h>
2 #include <linux/sched.h>
4 #include <linux/path.h>
5 #include <linux/slab.h>
8 * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
11 void set_fs_root(struct fs_struct *fs, struct path *path)
15 write_lock(&fs->lock);
19 write_unlock(&fs->lock);
25 * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
28 void set_fs_pwd(struct fs_struct *fs, struct path *path)
32 write_lock(&fs->lock);
36 write_unlock(&fs->lock);
42 void chroot_fs_refs(struct path *old_root, struct path *new_root)
44 struct task_struct *g, *p;
48 read_lock(&tasklist_lock);
49 do_each_thread(g, p) {
53 write_lock(&fs->lock);
54 if (fs->root.dentry == old_root->dentry
55 && fs->root.mnt == old_root->mnt) {
60 if (fs->pwd.dentry == old_root->dentry
61 && fs->pwd.mnt == old_root->mnt) {
66 write_unlock(&fs->lock);
69 } while_each_thread(g, p);
70 read_unlock(&tasklist_lock);
75 void free_fs_struct(struct fs_struct *fs)
79 kmem_cache_free(fs_cachep, fs);
82 void exit_fs(struct task_struct *tsk)
84 struct fs_struct *fs = tsk->fs;
89 write_lock(&fs->lock);
92 write_unlock(&fs->lock);
99 struct fs_struct *copy_fs_struct(struct fs_struct *old)
101 struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
102 /* We don't need to lock fs - think why ;-) */
106 rwlock_init(&fs->lock);
107 fs->umask = old->umask;
108 read_lock(&old->lock);
109 fs->root = old->root;
110 path_get(&old->root);
113 read_unlock(&old->lock);
118 int unshare_fs_struct(void)
120 struct fs_struct *fs = current->fs;
121 struct fs_struct *new_fs = copy_fs_struct(fs);
128 write_lock(&fs->lock);
130 current->fs = new_fs;
131 write_unlock(&fs->lock);
132 task_unlock(current);
139 EXPORT_SYMBOL_GPL(unshare_fs_struct);
141 /* to be mentioned only in INIT_TASK */
142 struct fs_struct init_fs = {
144 .lock = __RW_LOCK_UNLOCKED(init_fs.lock),
148 void daemonize_fs_struct(void)
150 struct fs_struct *fs = current->fs;
157 write_lock(&init_fs.lock);
159 write_unlock(&init_fs.lock);
161 write_lock(&fs->lock);
162 current->fs = &init_fs;
164 write_unlock(&fs->lock);
166 task_unlock(current);