[linux-2.6-block.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_follow_link(struct dentry *dentry, void **cookie)
{
	struct pid_namespace *ns = dentry->d_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, GFP_KERNEL);
	if (!name)
		return ERR_PTR(-ENOMEM);
	sprintf(name, "%d", tgid);
	return *cookie = name;
}

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 = d_inode(s->s_root);
	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);
}
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
6e77137b	21	static const char proc_self_follow_link(struct dentry dentry, void **cookie)
e656d8a6 EB	22	{
	23	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
	24	pid_t tgid = task_tgid_nr_ns(current, ns);
680baacb AV	25	char *name;
	26
	27	if (!tgid)
	28	return ERR_PTR(-ENOENT);
	29	/* 11 for max length of signed int in decimal + NULL term */
	30	name = kmalloc(12, GFP_KERNEL);
	31	if (!name)
	32	return ERR_PTR(-ENOMEM);
	33	sprintf(name, "%d", tgid);
	34	return *cookie = name;
e656d8a6 EB	35	}
e656d8a6 EB	36
e656d8a6 EB	37	static const struct inode_operations proc_self_inode_operations = {
	38	.readlink = proc_self_readlink,
	39	.follow_link = proc_self_follow_link,
87dc800b	40	.put_link = kfree_put_link,
e656d8a6 EB	41	};
e656d8a6 EB	42
021ada7d AV	43	static unsigned self_inum;
	44
	45	int proc_setup_self(struct super_block *s)
e656d8a6	46	{
2b0143b5	47	struct inode *root_inode = d_inode(s->s_root);
021ada7d AV	48	struct pid_namespace *ns = s->s_fs_info;
	49	struct dentry *self;
	50
	51	mutex_lock(&root_inode->i_mutex);
	52	self = d_alloc_name(s->s_root, "self");
	53	if (self) {
	54	struct inode *inode = new_inode_pseudo(s);
	55	if (inode) {
	56	inode->i_ino = self_inum;
	57	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	58	inode->i_mode = S_IFLNK \| S_IRWXUGO;
	59	inode->i_uid = GLOBAL_ROOT_UID;
	60	inode->i_gid = GLOBAL_ROOT_GID;
	61	inode->i_op = &proc_self_inode_operations;
	62	d_add(self, inode);
	63	} else {
	64	dput(self);
	65	self = ERR_PTR(-ENOMEM);
	66	}
	67	} else {
	68	self = ERR_PTR(-ENOMEM);
	69	}
	70	mutex_unlock(&root_inode->i_mutex);
	71	if (IS_ERR(self)) {
	72	pr_err("proc_fill_super: can't allocate /proc/self\n");
	73	return PTR_ERR(self);
	74	}
	75	ns->proc_self = self;
	76	return 0;
	77	}
e656d8a6	78
021ada7d AV	79	void __init proc_self_init(void)
	80	{
	81	proc_alloc_inum(&self_inum);
e656d8a6	82	}