84 lines
2 KiB
C
84 lines
2 KiB
C
#include <linux/sched.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/pid_namespace.h>
|
|
#include "internal.h"
|
|
|
|
/*
|
|
* /proc/self:
|
|
*/
|
|
static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
|
|
int buflen)
|
|
{
|
|
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
|
|
pid_t tgid = task_tgid_nr_ns(current, ns);
|
|
char tmp[PROC_NUMBUF];
|
|
if (!tgid)
|
|
return -ENOENT;
|
|
sprintf(tmp, "%d", tgid);
|
|
return readlink_copy(buffer, buflen, tmp);
|
|
}
|
|
|
|
static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
|
|
{
|
|
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
|
|
pid_t tgid = task_tgid_nr_ns(current, ns);
|
|
char *name = ERR_PTR(-ENOENT);
|
|
if (tgid) {
|
|
/* 11 for max length of signed int in decimal + NULL term */
|
|
name = kmalloc(12, GFP_KERNEL);
|
|
if (!name)
|
|
name = ERR_PTR(-ENOMEM);
|
|
else
|
|
sprintf(name, "%d", tgid);
|
|
}
|
|
nd_set_link(nd, name);
|
|
return NULL;
|
|
}
|
|
|
|
static const struct inode_operations proc_self_inode_operations = {
|
|
.readlink = proc_self_readlink,
|
|
.follow_link = proc_self_follow_link,
|
|
.put_link = kfree_put_link,
|
|
};
|
|
|
|
static unsigned self_inum;
|
|
|
|
int proc_setup_self(struct super_block *s)
|
|
{
|
|
struct inode *root_inode = s->s_root->d_inode;
|
|
struct pid_namespace *ns = s->s_fs_info;
|
|
struct dentry *self;
|
|
|
|
mutex_lock(&root_inode->i_mutex);
|
|
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->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);
|
|
}
|
|
mutex_unlock(&root_inode->i_mutex);
|
|
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);
|
|
}
|