[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / proc / self.c

#include <linux/sched.h>
#include <linux/namei.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 vfs_readlink(dentry,buffer,buflen,tmp);
}

static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
	pid_t tgid = task_tgid_nr_ns(current, ns);
	char *name = ERR_PTR(-ENOENT);
	if (tgid) {
		/* 11 for max length of signed int in decimal + NULL term */
		name = kmalloc(12, GFP_KERNEL);
		if (!name)
			name = ERR_PTR(-ENOMEM);
		else
			sprintf(name, "%d", tgid);
	}
	nd_set_link(nd, name);
	return NULL;
}

static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
				void *cookie)
{
	char *s = nd_get_link(nd);
	if (!IS_ERR(s))
		kfree(s);
}

static const struct inode_operations proc_self_inode_operations = {
	.readlink	= proc_self_readlink,
	.follow_link	= proc_self_follow_link,
	.put_link	= proc_self_put_link,
};

static unsigned self_inum;

int proc_setup_self(struct super_block *s)
{
	struct inode *root_inode = s->s_root->d_inode;
	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 EB	1	#include <linux/sched.h>
e656d8a6 EB	2	#include <linux/namei.h>
0d01ff25	3	#include <linux/slab.h>
021ada7d AV	4	#include <linux/pid_namespace.h>
021ada7d AV	5	#include "internal.h"
e656d8a6 EB	6
	7	/*
	8	* /proc/self:
	9	*/
	10	static int proc_self_readlink(struct dentry dentry, char __user buffer,
	11	int buflen)
	12	{
	13	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
	14	pid_t tgid = task_tgid_nr_ns(current, ns);
	15	char tmp[PROC_NUMBUF];
	16	if (!tgid)
	17	return -ENOENT;
	18	sprintf(tmp, "%d", tgid);
	19	return vfs_readlink(dentry,buffer,buflen,tmp);
	20	}
	21
	22	static void proc_self_follow_link(struct dentry dentry, struct nameidata *nd)
	23	{
	24	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
	25	pid_t tgid = task_tgid_nr_ns(current, ns);
	26	char *name = ERR_PTR(-ENOENT);
	27	if (tgid) {
	28	/* 11 for max length of signed int in decimal + NULL term */
	29	name = kmalloc(12, GFP_KERNEL);
	30	if (!name)
	31	name = ERR_PTR(-ENOMEM);
	32	else
	33	sprintf(name, "%d", tgid);
	34	}
	35	nd_set_link(nd, name);
	36	return NULL;
	37	}
	38
	39	static void proc_self_put_link(struct dentry dentry, struct nameidata nd,
	40	void *cookie)
	41	{
	42	char *s = nd_get_link(nd);
	43	if (!IS_ERR(s))
	44	kfree(s);
	45	}
	46
	47	static const struct inode_operations proc_self_inode_operations = {
	48	.readlink = proc_self_readlink,
	49	.follow_link = proc_self_follow_link,
	50	.put_link = proc_self_put_link,
	51	};
	52
021ada7d AV	53	static unsigned self_inum;
	54
	55	int proc_setup_self(struct super_block *s)
e656d8a6	56	{
021ada7d AV	57	struct inode *root_inode = s->s_root->d_inode;
	58	struct pid_namespace *ns = s->s_fs_info;
	59	struct dentry *self;
	60
	61	mutex_lock(&root_inode->i_mutex);
	62	self = d_alloc_name(s->s_root, "self");
	63	if (self) {
	64	struct inode *inode = new_inode_pseudo(s);
	65	if (inode) {
	66	inode->i_ino = self_inum;
	67	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	68	inode->i_mode = S_IFLNK \| S_IRWXUGO;
	69	inode->i_uid = GLOBAL_ROOT_UID;
	70	inode->i_gid = GLOBAL_ROOT_GID;
	71	inode->i_op = &proc_self_inode_operations;
	72	d_add(self, inode);
	73	} else {
	74	dput(self);
	75	self = ERR_PTR(-ENOMEM);
	76	}
	77	} else {
	78	self = ERR_PTR(-ENOMEM);
	79	}
	80	mutex_unlock(&root_inode->i_mutex);
	81	if (IS_ERR(self)) {
	82	pr_err("proc_fill_super: can't allocate /proc/self\n");
	83	return PTR_ERR(self);
	84	}
	85	ns->proc_self = self;
	86	return 0;
	87	}
e656d8a6	88
021ada7d AV	89	void __init proc_self_init(void)
	90	{
	91	proc_alloc_inum(&self_inum);
e656d8a6	92	}