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

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/pid_namespace.h>
#include "internal.h"

/*
 * /proc/thread_self:
 */
static const char *proc_thread_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);
	pid_t pid = task_pid_nr_ns(current, ns);
	char *name;

	if (!pid)
		return ERR_PTR(-ENOENT);
	name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF,
				dentry ? GFP_KERNEL : GFP_ATOMIC);
	if (unlikely(!name))
		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
	sprintf(name, "%d/task/%d", tgid, pid);
	set_delayed_call(done, kfree_link, name);
	return name;
}

static const struct inode_operations proc_thread_self_inode_operations = {
	.get_link	= proc_thread_self_get_link,
};

static unsigned thread_self_inum;

int proc_setup_thread_self(struct super_block *s)
{
	struct inode *root_inode = d_inode(s->s_root);
	struct pid_namespace *ns = s->s_fs_info;
	struct dentry *thread_self;

	inode_lock(root_inode);
	thread_self = d_alloc_name(s->s_root, "thread-self");
	if (thread_self) {
		struct inode *inode = new_inode_pseudo(s);
		if (inode) {
			inode->i_ino = thread_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_thread_self_inode_operations;
			d_add(thread_self, inode);
		} else {
			dput(thread_self);
			thread_self = ERR_PTR(-ENOMEM);
		}
	} else {
		thread_self = ERR_PTR(-ENOMEM);
	}
	inode_unlock(root_inode);
	if (IS_ERR(thread_self)) {
		pr_err("proc_fill_super: can't allocate /proc/thread_self\n");
		return PTR_ERR(thread_self);
	}
	ns->proc_thread_self = thread_self;
	return 0;
}

void __init proc_thread_self_init(void)
{
	proc_alloc_inum(&thread_self_inum);
}
Commit	Line	Data
0097875b	1	#include <linux/sched.h>
0097875b EB	2	#include <linux/slab.h>
	3	#include <linux/pid_namespace.h>
	4	#include "internal.h"
	5
	6	/*
	7	* /proc/thread_self:
	8	*/
6b255391	9	static const char proc_thread_self_get_link(struct dentry dentry,
fceef393 AV	10	struct inode *inode,
fceef393 AV	11	struct delayed_call *done)
0097875b	12	{
6b255391	13	struct pid_namespace *ns = inode->i_sb->s_fs_info;
0097875b EB	14	pid_t tgid = task_tgid_nr_ns(current, ns);
0097875b EB	15	pid_t pid = task_pid_nr_ns(current, ns);
680baacb AV	16	char *name;
	17
	18	if (!pid)
	19	return ERR_PTR(-ENOENT);
1a384eaa AV	20	name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF,
	21	dentry ? GFP_KERNEL : GFP_ATOMIC);
	22	if (unlikely(!name))
	23	return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
680baacb	24	sprintf(name, "%d/task/%d", tgid, pid);
fceef393 AV	25	set_delayed_call(done, kfree_link, name);
fceef393 AV	26	return name;
0097875b EB	27	}
	28
	29	static const struct inode_operations proc_thread_self_inode_operations = {
6b255391	30	.get_link = proc_thread_self_get_link,
0097875b EB	31	};
	32
	33	static unsigned thread_self_inum;
	34
	35	int proc_setup_thread_self(struct super_block *s)
	36	{
2b0143b5	37	struct inode *root_inode = d_inode(s->s_root);
0097875b EB	38	struct pid_namespace *ns = s->s_fs_info;
	39	struct dentry *thread_self;
	40
5955102c	41	inode_lock(root_inode);
0097875b EB	42	thread_self = d_alloc_name(s->s_root, "thread-self");
	43	if (thread_self) {
	44	struct inode *inode = new_inode_pseudo(s);
	45	if (inode) {
	46	inode->i_ino = thread_self_inum;
078cd827	47	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
0097875b EB	48	inode->i_mode = S_IFLNK \| S_IRWXUGO;
	49	inode->i_uid = GLOBAL_ROOT_UID;
	50	inode->i_gid = GLOBAL_ROOT_GID;
	51	inode->i_op = &proc_thread_self_inode_operations;
	52	d_add(thread_self, inode);
	53	} else {
	54	dput(thread_self);
	55	thread_self = ERR_PTR(-ENOMEM);
	56	}
	57	} else {
	58	thread_self = ERR_PTR(-ENOMEM);
	59	}
5955102c	60	inode_unlock(root_inode);
0097875b EB	61	if (IS_ERR(thread_self)) {
	62	pr_err("proc_fill_super: can't allocate /proc/thread_self\n");
	63	return PTR_ERR(thread_self);
	64	}
	65	ns->proc_thread_self = thread_self;
	66	return 0;
	67	}
	68
	69	void __init proc_thread_self_init(void)
	70	{
	71	proc_alloc_inum(&thread_self_inum);
	72	}