1 #include <linux/module.h>
2 #include <linux/sched.h>
4 #include <linux/path.h>
5 #include <linux/slab.h>
6 #include <linux/fs_struct.h>
9 * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
12 void set_fs_root(struct fs_struct
*fs
, struct path
*path
)
16 write_lock(&fs
->lock
);
20 write_unlock(&fs
->lock
);
26 * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
29 void set_fs_pwd(struct fs_struct
*fs
, struct path
*path
)
33 write_lock(&fs
->lock
);
37 write_unlock(&fs
->lock
);
43 void chroot_fs_refs(struct path
*old_root
, struct path
*new_root
)
45 struct task_struct
*g
, *p
;
49 read_lock(&tasklist_lock
);
50 do_each_thread(g
, p
) {
54 write_lock(&fs
->lock
);
55 if (fs
->root
.dentry
== old_root
->dentry
56 && fs
->root
.mnt
== old_root
->mnt
) {
61 if (fs
->pwd
.dentry
== old_root
->dentry
62 && fs
->pwd
.mnt
== old_root
->mnt
) {
67 write_unlock(&fs
->lock
);
70 } while_each_thread(g
, p
);
71 read_unlock(&tasklist_lock
);
76 void free_fs_struct(struct fs_struct
*fs
)
80 kmem_cache_free(fs_cachep
, fs
);
83 void exit_fs(struct task_struct
*tsk
)
85 struct fs_struct
*fs
= tsk
->fs
;
90 write_lock(&fs
->lock
);
93 write_unlock(&fs
->lock
);
100 struct fs_struct
*copy_fs_struct(struct fs_struct
*old
)
102 struct fs_struct
*fs
= kmem_cache_alloc(fs_cachep
, GFP_KERNEL
);
103 /* We don't need to lock fs - think why ;-) */
107 rwlock_init(&fs
->lock
);
108 fs
->umask
= old
->umask
;
109 read_lock(&old
->lock
);
110 fs
->root
= old
->root
;
111 path_get(&old
->root
);
114 read_unlock(&old
->lock
);
119 int unshare_fs_struct(void)
121 struct fs_struct
*fs
= current
->fs
;
122 struct fs_struct
*new_fs
= copy_fs_struct(fs
);
129 write_lock(&fs
->lock
);
131 current
->fs
= new_fs
;
132 write_unlock(&fs
->lock
);
133 task_unlock(current
);
140 EXPORT_SYMBOL_GPL(unshare_fs_struct
);
142 int current_umask(void)
144 return current
->fs
->umask
;
146 EXPORT_SYMBOL(current_umask
);
148 /* to be mentioned only in INIT_TASK */
149 struct fs_struct init_fs
= {
151 .lock
= __RW_LOCK_UNLOCKED(init_fs
.lock
),
155 void daemonize_fs_struct(void)
157 struct fs_struct
*fs
= current
->fs
;
164 write_lock(&init_fs
.lock
);
166 write_unlock(&init_fs
.lock
);
168 write_lock(&fs
->lock
);
169 current
->fs
= &init_fs
;
171 write_unlock(&fs
->lock
);
173 task_unlock(current
);
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