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Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e656d8a6 | 2 | #include <linux/sched.h> |
0d01ff25 | 3 | #include <linux/slab.h> |
021ada7d AV |
4 | #include <linux/pid_namespace.h> |
5 | #include "internal.h" | |
e656d8a6 EB |
6 | |
7 | /* | |
8 | * /proc/self: | |
9 | */ | |
6b255391 | 10 | static const char *proc_self_get_link(struct dentry *dentry, |
fceef393 AV |
11 | struct inode *inode, |
12 | struct delayed_call *done) | |
e656d8a6 | 13 | { |
6b255391 | 14 | struct pid_namespace *ns = inode->i_sb->s_fs_info; |
e656d8a6 | 15 | pid_t tgid = task_tgid_nr_ns(current, ns); |
680baacb AV |
16 | char *name; |
17 | ||
18 | if (!tgid) | |
19 | return ERR_PTR(-ENOENT); | |
20 | /* 11 for max length of signed int in decimal + NULL term */ | |
1a384eaa AV |
21 | name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC); |
22 | if (unlikely(!name)) | |
23 | return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD); | |
680baacb | 24 | sprintf(name, "%d", tgid); |
fceef393 AV |
25 | set_delayed_call(done, kfree_link, name); |
26 | return name; | |
e656d8a6 EB |
27 | } |
28 | ||
e656d8a6 | 29 | static const struct inode_operations proc_self_inode_operations = { |
6b255391 | 30 | .get_link = proc_self_get_link, |
e656d8a6 EB |
31 | }; |
32 | ||
021ada7d AV |
33 | static unsigned self_inum; |
34 | ||
35 | int proc_setup_self(struct super_block *s) | |
e656d8a6 | 36 | { |
2b0143b5 | 37 | struct inode *root_inode = d_inode(s->s_root); |
021ada7d AV |
38 | struct pid_namespace *ns = s->s_fs_info; |
39 | struct dentry *self; | |
40 | ||
5955102c | 41 | inode_lock(root_inode); |
021ada7d AV |
42 | self = d_alloc_name(s->s_root, "self"); |
43 | if (self) { | |
44 | struct inode *inode = new_inode_pseudo(s); | |
45 | if (inode) { | |
46 | inode->i_ino = self_inum; | |
078cd827 | 47 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); |
021ada7d AV |
48 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
49 | inode->i_uid = GLOBAL_ROOT_UID; | |
50 | inode->i_gid = GLOBAL_ROOT_GID; | |
51 | inode->i_op = &proc_self_inode_operations; | |
52 | d_add(self, inode); | |
53 | } else { | |
54 | dput(self); | |
55 | self = ERR_PTR(-ENOMEM); | |
56 | } | |
57 | } else { | |
58 | self = ERR_PTR(-ENOMEM); | |
59 | } | |
5955102c | 60 | inode_unlock(root_inode); |
021ada7d AV |
61 | if (IS_ERR(self)) { |
62 | pr_err("proc_fill_super: can't allocate /proc/self\n"); | |
63 | return PTR_ERR(self); | |
64 | } | |
65 | ns->proc_self = self; | |
66 | return 0; | |
67 | } | |
e656d8a6 | 68 | |
021ada7d AV |
69 | void __init proc_self_init(void) |
70 | { | |
71 | proc_alloc_inum(&self_inum); | |
e656d8a6 | 72 | } |