[deliverable/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, void **cookie)
{
	struct pid_namespace *ns = inode->i_sb->s_fs_info;
	pid_t tgid = task_tgid_nr_ns(current, ns);
	char *name;

	if (!dentry)
		return ERR_PTR(-ECHILD);
	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,
	.get_link	= proc_self_get_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
6b255391 AV	21	static const char proc_self_get_link(struct dentry dentry,
6b255391 AV	22	struct inode inode, void *cookie)
e656d8a6	23	{
6b255391	24	struct pid_namespace *ns = inode->i_sb->s_fs_info;
e656d8a6	25	pid_t tgid = task_tgid_nr_ns(current, ns);
680baacb AV	26	char *name;
680baacb AV	27
6b255391 AV	28	if (!dentry)
6b255391 AV	29	return ERR_PTR(-ECHILD);
680baacb AV	30	if (!tgid)
	31	return ERR_PTR(-ENOENT);
	32	/* 11 for max length of signed int in decimal + NULL term */
	33	name = kmalloc(12, GFP_KERNEL);
	34	if (!name)
	35	return ERR_PTR(-ENOMEM);
	36	sprintf(name, "%d", tgid);
	37	return *cookie = 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,
87dc800b	43	.put_link = kfree_put_link,
e656d8a6 EB	44	};
e656d8a6 EB	45
021ada7d AV	46	static unsigned self_inum;
	47
	48	int proc_setup_self(struct super_block *s)
e656d8a6	49	{
2b0143b5	50	struct inode *root_inode = d_inode(s->s_root);
021ada7d AV	51	struct pid_namespace *ns = s->s_fs_info;
	52	struct dentry *self;
	53
	54	mutex_lock(&root_inode->i_mutex);
	55	self = d_alloc_name(s->s_root, "self");
	56	if (self) {
	57	struct inode *inode = new_inode_pseudo(s);
	58	if (inode) {
	59	inode->i_ino = self_inum;
	60	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	61	inode->i_mode = S_IFLNK \| S_IRWXUGO;
	62	inode->i_uid = GLOBAL_ROOT_UID;
	63	inode->i_gid = GLOBAL_ROOT_GID;
	64	inode->i_op = &proc_self_inode_operations;
	65	d_add(self, inode);
	66	} else {
	67	dput(self);
	68	self = ERR_PTR(-ENOMEM);
	69	}
	70	} else {
	71	self = ERR_PTR(-ENOMEM);
	72	}
	73	mutex_unlock(&root_inode->i_mutex);
	74	if (IS_ERR(self)) {
	75	pr_err("proc_fill_super: can't allocate /proc/self\n");
	76	return PTR_ERR(self);
	77	}
	78	ns->proc_self = self;
	79	return 0;
	80	}
e656d8a6	81
021ada7d AV	82	void __init proc_self_init(void)
	83	{
	84	proc_alloc_inum(&self_inum);
e656d8a6	85	}