[mirror_ubuntu-artful-kernel.git] / fs / proc / self.c

#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 = inode->i_sb->s_fs_info;
	pid_t tgid = task_tgid_nr_ns(current, ns);
	char *name;

	if (!tgid)
		return ERR_PTR(-ENOENT);
	/* 11 for max length of signed int in decimal + NULL term */
	name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC);
	if (unlikely(!name))
		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
	sprintf(name, "%d", 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;

int proc_setup_self(struct super_block *s)
{
	struct inode *root_inode = d_inode(s->s_root);
	struct pid_namespace *ns = s->s_fs_info;
	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);
}
Commit	Line	Data
e656d8a6	1	#include <linux/sched.h>
0d01ff25	2	#include <linux/slab.h>
021ada7d AV	3	#include <linux/pid_namespace.h>
021ada7d AV	4	#include "internal.h"
e656d8a6 EB	5
	6	/*
	7	* /proc/self:
	8	*/
6b255391	9	static const char proc_self_get_link(struct dentry dentry,
fceef393 AV	10	struct inode *inode,
fceef393 AV	11	struct delayed_call *done)
e656d8a6	12	{
6b255391	13	struct pid_namespace *ns = inode->i_sb->s_fs_info;
e656d8a6	14	pid_t tgid = task_tgid_nr_ns(current, ns);
680baacb AV	15	char *name;
	16
	17	if (!tgid)
	18	return ERR_PTR(-ENOENT);
	19	/* 11 for max length of signed int in decimal + NULL term */
1a384eaa AV	20	name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC);
	21	if (unlikely(!name))
	22	return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
680baacb	23	sprintf(name, "%d", tgid);
fceef393 AV	24	set_delayed_call(done, kfree_link, name);
fceef393 AV	25	return name;
e656d8a6 EB	26	}
e656d8a6 EB	27
e656d8a6	28	static const struct inode_operations proc_self_inode_operations = {
6b255391	29	.get_link = proc_self_get_link,
e656d8a6 EB	30	};
e656d8a6 EB	31
021ada7d AV	32	static unsigned self_inum;
	33
	34	int proc_setup_self(struct super_block *s)
e656d8a6	35	{
2b0143b5	36	struct inode *root_inode = d_inode(s->s_root);
021ada7d AV	37	struct pid_namespace *ns = s->s_fs_info;
	38	struct dentry *self;
	39
5955102c	40	inode_lock(root_inode);
021ada7d AV	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;
078cd827	46	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
021ada7d AV	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	}
5955102c	59	inode_unlock(root_inode);
021ada7d AV	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	}
e656d8a6	67
021ada7d AV	68	void __init proc_self_init(void)
	69	{
	70	proc_alloc_inum(&self_inum);
e656d8a6	71	}