1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/cache.h>
 3#include <linux/sched.h>
 4#include <linux/slab.h>
 5#include <linux/pid_namespace.h>
 6#include "internal.h"
 7
 8/*
 9 * /proc/self:
10 */
11static const char *proc_self_get_link(struct dentry *dentry,
12				      struct inode *inode,
13				      struct delayed_call *done)
14{
15	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
16	pid_t tgid = task_tgid_nr_ns(current, ns);
17	char *name;
18
19	if (!tgid)
20		return ERR_PTR(-ENOENT);
21	/* max length of unsigned int in decimal + NULL term */
22	name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
23	if (unlikely(!name))
24		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
25	sprintf(name, "%u", tgid);
26	set_delayed_call(done, kfree_link, name);
27	return name;
28}
29
30static const struct inode_operations proc_self_inode_operations = {
31	.get_link	= proc_self_get_link,
32};
33
34static unsigned self_inum __ro_after_init;
35
36int proc_setup_self(struct super_block *s)
37{
38	struct inode *root_inode = d_inode(s->s_root);
39	struct proc_fs_info *fs_info = proc_sb_info(s);
40	struct dentry *self;
41	int ret = -ENOMEM;
42
43	inode_lock(root_inode);
44	self = d_alloc_name(s->s_root, "self");
45	if (self) {
46		struct inode *inode = new_inode(s);
47		if (inode) {
48			inode->i_ino = self_inum;
49			simple_inode_init_ts(inode);
50			inode->i_mode = S_IFLNK | S_IRWXUGO;
51			inode->i_uid = GLOBAL_ROOT_UID;
52			inode->i_gid = GLOBAL_ROOT_GID;
53			inode->i_op = &proc_self_inode_operations;
54			d_add(self, inode);
55			ret = 0;
56		} else {
57			dput(self);
 
58		}
 
 
59	}
60	inode_unlock(root_inode);
61
62	if (ret)
63		pr_err("proc_fill_super: can't allocate /proc/self\n");
64	else
65		fs_info->proc_self = self;
66
67	return ret;
68}
69
70void __init proc_self_init(void)
71{
72	proc_alloc_inum(&self_inum);
73}

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