[linux.git] / fs / proc / self.c

#include <linux/sched.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 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 = {
	.readlink	= proc_self_readlink,
	.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->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	*/
	9	static int proc_self_readlink(struct dentry dentry, char __user buffer,
	10	int buflen)
	11	{
	12	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
	13	pid_t tgid = task_tgid_nr_ns(current, ns);
	14	char tmp[PROC_NUMBUF];
	15	if (!tgid)
	16	return -ENOENT;
	17	sprintf(tmp, "%d", tgid);
5d826c84	18	return readlink_copy(buffer, buflen, tmp);
e656d8a6 EB	19	}
e656d8a6 EB	20
6b255391	21	static const char proc_self_get_link(struct dentry dentry,
fceef393 AV	22	struct inode *inode,
fceef393 AV	23	struct delayed_call *done)
e656d8a6	24	{
6b255391	25	struct pid_namespace *ns = inode->i_sb->s_fs_info;
e656d8a6	26	pid_t tgid = task_tgid_nr_ns(current, ns);
680baacb AV	27	char *name;
	28
	29	if (!tgid)
	30	return ERR_PTR(-ENOENT);
	31	/* 11 for max length of signed int in decimal + NULL term */
1a384eaa AV	32	name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC);
	33	if (unlikely(!name))
	34	return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
680baacb	35	sprintf(name, "%d", tgid);
fceef393 AV	36	set_delayed_call(done, kfree_link, name);
fceef393 AV	37	return name;
e656d8a6 EB	38	}
e656d8a6 EB	39
e656d8a6 EB	40	static const struct inode_operations proc_self_inode_operations = {
e656d8a6 EB	41	.readlink = proc_self_readlink,
6b255391	42	.get_link = proc_self_get_link,
e656d8a6 EB	43	};
e656d8a6 EB	44
021ada7d AV	45	static unsigned self_inum;
	46
	47	int proc_setup_self(struct super_block *s)
e656d8a6	48	{
2b0143b5	49	struct inode *root_inode = d_inode(s->s_root);
021ada7d AV	50	struct pid_namespace *ns = s->s_fs_info;
	51	struct dentry *self;
	52
5955102c	53	inode_lock(root_inode);
021ada7d AV	54	self = d_alloc_name(s->s_root, "self");
	55	if (self) {
	56	struct inode *inode = new_inode_pseudo(s);
	57	if (inode) {
	58	inode->i_ino = self_inum;
	59	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	60	inode->i_mode = S_IFLNK \| S_IRWXUGO;
	61	inode->i_uid = GLOBAL_ROOT_UID;
	62	inode->i_gid = GLOBAL_ROOT_GID;
	63	inode->i_op = &proc_self_inode_operations;
	64	d_add(self, inode);
	65	} else {
	66	dput(self);
	67	self = ERR_PTR(-ENOMEM);
	68	}
	69	} else {
	70	self = ERR_PTR(-ENOMEM);
	71	}
5955102c	72	inode_unlock(root_inode);
021ada7d AV	73	if (IS_ERR(self)) {
	74	pr_err("proc_fill_super: can't allocate /proc/self\n");
	75	return PTR_ERR(self);
	76	}
	77	ns->proc_self = self;
	78	return 0;
	79	}
e656d8a6	80
021ada7d AV	81	void __init proc_self_init(void)
	82	{
	83	proc_alloc_inum(&self_inum);
e656d8a6	84	}