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 put_fs_struct(struct fs_struct *fs)
77 /* No need to hold fs->lock if we are killing it */
78 if (atomic_dec_and_test(&fs->count)) {
81 kmem_cache_free(fs_cachep, fs);
85 void exit_fs(struct task_struct *tsk)
87 struct fs_struct * fs = tsk->fs;
97 struct fs_struct *copy_fs_struct(struct fs_struct *old)
99 struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
100 /* We don't need to lock fs - think why ;-) */
102 atomic_set(&fs->count, 1);
103 rwlock_init(&fs->lock);
104 fs->umask = old->umask;
105 read_lock(&old->lock);
106 fs->root = old->root;
107 path_get(&old->root);
110 read_unlock(&old->lock);
115 int unshare_fs_struct(void)
117 struct fs_struct *fsp = copy_fs_struct(current->fs);
124 EXPORT_SYMBOL_GPL(unshare_fs_struct);
126 /* to be mentioned only in INIT_TASK */
127 struct fs_struct init_fs = {
128 .count = ATOMIC_INIT(1),
129 .lock = __RW_LOCK_UNLOCKED(init_fs.lock),
133 void daemonize_fs_struct(void)
135 struct fs_struct *fs;
137 exit_fs(current); /* current->fs->count--; */
140 atomic_inc(&fs->count);