74 lines
1.8 KiB
C
74 lines
1.8 KiB
C
// 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);
|
|
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 pid_namespace *ns = proc_pid_ns(root_inode);
|
|
struct dentry *self;
|
|
|
|
inode_lock(root_inode);
|
|
self = d_alloc_name(s->s_root, "self");
|
|
if (self) {
|
|
struct inode *inode = new_inode_pseudo(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);
|
|
} else {
|
|
dput(self);
|
|
self = ERR_PTR(-ENOMEM);
|
|
}
|
|
} else {
|
|
self = ERR_PTR(-ENOMEM);
|
|
}
|
|
inode_unlock(root_inode);
|
|
if (IS_ERR(self)) {
|
|
pr_err("proc_fill_super: can't allocate /proc/self\n");
|
|
return PTR_ERR(self);
|
|
}
|
|
ns->proc_self = self;
|
|
return 0;
|
|
}
|
|
|
|
void __init proc_self_init(void)
|
|
{
|
|
proc_alloc_inum(&self_inum);
|
|
}
|