// SPDX-License-Identifier: GPL-2.0
|
#include <linux/cache.h>
|
#include <linux/sched.h>
|
#include <linux/slab.h>
|
#include <linux/pid_namespace.h>
|
#include "internal.h"
|
|
/*
|
* /proc/self:
|
*/
|
static const char *proc_self_get_link(struct dentry *dentry,
|
struct inode *inode,
|
struct delayed_call *done)
|
{
|
struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
|
pid_t tgid = task_tgid_nr_ns(current, ns);
|
char *name;
|
|
if (!tgid)
|
return ERR_PTR(-ENOENT);
|
/* max length of unsigned int in decimal + NULL term */
|
name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
|
if (unlikely(!name))
|
return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
|
sprintf(name, "%u", tgid);
|
set_delayed_call(done, kfree_link, name);
|
return name;
|
}
|
|
static const struct inode_operations proc_self_inode_operations = {
|
.get_link = proc_self_get_link,
|
};
|
|
static unsigned self_inum __ro_after_init;
|
|
int proc_setup_self(struct super_block *s)
|
{
|
struct inode *root_inode = d_inode(s->s_root);
|
struct proc_fs_info *fs_info = proc_sb_info(s);
|
struct dentry *self;
|
int ret = -ENOMEM;
|
|
inode_lock(root_inode);
|
self = d_alloc_name(s->s_root, "self");
|
if (self) {
|
struct inode *inode = new_inode(s);
|
if (inode) {
|
inode->i_ino = self_inum;
|
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
|
inode->i_mode = S_IFLNK | S_IRWXUGO;
|
inode->i_uid = GLOBAL_ROOT_UID;
|
inode->i_gid = GLOBAL_ROOT_GID;
|
inode->i_op = &proc_self_inode_operations;
|
d_add(self, inode);
|
ret = 0;
|
} else {
|
dput(self);
|
}
|
}
|
inode_unlock(root_inode);
|
|
if (ret)
|
pr_err("proc_fill_super: can't allocate /proc/self\n");
|
else
|
fs_info->proc_self = self;
|
|
return ret;
|
}
|
|
void __init proc_self_init(void)
|
{
|
proc_alloc_inum(&self_inum);
|
}
|
