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

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

/*
 * /proc/thread_self:
 */
static int proc_thread_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);
	pid_t pid = task_pid_nr_ns(current, ns);
	char tmp[PROC_NUMBUF + 6 + PROC_NUMBUF];
	if (!pid)
		return -ENOENT;
	sprintf(tmp, "%d/task/%d", tgid, pid);
	return readlink_copy(buffer, buflen, tmp);
}

static void *proc_thread_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);
	pid_t pid = task_pid_nr_ns(current, ns);
	char *name = ERR_PTR(-ENOENT);
	if (pid) {
		name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);
		if (!name)
			name = ERR_PTR(-ENOMEM);
		else
			sprintf(name, "%d/task/%d", tgid, pid);
	}
	nd_set_link(nd, name);
	return NULL;
}

static const struct inode_operations proc_thread_self_inode_operations = {
	.readlink	= proc_thread_self_readlink,
	.follow_link	= proc_thread_self_follow_link,
	.put_link	= kfree_put_link,
};

static unsigned thread_self_inum;

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

	mutex_lock(&root_inode->i_mutex);
	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->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);
	}
	mutex_unlock(&root_inode->i_mutex);
	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 EB	1	#include <linux/sched.h>
	2	#include <linux/namei.h>
	3	#include <linux/slab.h>
	4	#include <linux/pid_namespace.h>
	5	#include "internal.h"
	6
	7	/*
	8	* /proc/thread_self:
	9	*/
	10	static int proc_thread_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	pid_t pid = task_pid_nr_ns(current, ns);
	16	char tmp[PROC_NUMBUF + 6 + PROC_NUMBUF];
	17	if (!pid)
	18	return -ENOENT;
	19	sprintf(tmp, "%d/task/%d", tgid, pid);
	20	return readlink_copy(buffer, buflen, tmp);
	21	}
	22
	23	static void proc_thread_self_follow_link(struct dentry dentry, struct nameidata *nd)
	24	{
	25	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
	26	pid_t tgid = task_tgid_nr_ns(current, ns);
	27	pid_t pid = task_pid_nr_ns(current, ns);
	28	char *name = ERR_PTR(-ENOENT);
	29	if (pid) {
	30	name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);
	31	if (!name)
	32	name = ERR_PTR(-ENOMEM);
	33	else
	34	sprintf(name, "%d/task/%d", tgid, pid);
	35	}
	36	nd_set_link(nd, name);
	37	return NULL;
	38	}
	39
	40	static const struct inode_operations proc_thread_self_inode_operations = {
	41	.readlink = proc_thread_self_readlink,
	42	.follow_link = proc_thread_self_follow_link,
	43	.put_link = kfree_put_link,
	44	};
	45
	46	static unsigned thread_self_inum;
	47
	48	int proc_setup_thread_self(struct super_block *s)
	49	{
	50	struct inode *root_inode = s->s_root->d_inode;
	51	struct pid_namespace *ns = s->s_fs_info;
	52	struct dentry *thread_self;
	53
	54	mutex_lock(&root_inode->i_mutex);
	55	thread_self = d_alloc_name(s->s_root, "thread-self");
	56	if (thread_self) {
	57	struct inode *inode = new_inode_pseudo(s);
	58	if (inode) {
	59	inode->i_ino = thread_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_thread_self_inode_operations;
65	d_add(thread_self, inode);
66	} else {
67	dput(thread_self);
68	thread_self = ERR_PTR(-ENOMEM);
69	}
70	} else {
71	thread_self = ERR_PTR(-ENOMEM);
72	}
73	mutex_unlock(&root_inode->i_mutex);
74	if (IS_ERR(thread_self)) {
75	pr_err("proc_fill_super: can't allocate /proc/thread_self\n");
76	return PTR_ERR(thread_self);
77	}
78	ns->proc_thread_self = thread_self;
79	return 0;
80	}
81
82	void __init proc_thread_self_init(void)
83	{
84	proc_alloc_inum(&thread_self_inum);
85	}