af_unix.c 62.3 KB
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/*
 * NET4:	Implementation of BSD Unix domain sockets.
 *
4
 * Authors:	Alan Cox, <alan@lxorguk.ukuu.org.uk>
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 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Fixes:
 *		Linus Torvalds	:	Assorted bug cures.
 *		Niibe Yutaka	:	async I/O support.
 *		Carsten Paeth	:	PF_UNIX check, address fixes.
 *		Alan Cox	:	Limit size of allocated blocks.
 *		Alan Cox	:	Fixed the stupid socketpair bug.
 *		Alan Cox	:	BSD compatibility fine tuning.
 *		Alan Cox	:	Fixed a bug in connect when interrupted.
 *		Alan Cox	:	Sorted out a proper draft version of
 *					file descriptor passing hacked up from
 *					Mike Shaver's work.
 *		Marty Leisner	:	Fixes to fd passing
 *		Nick Nevin	:	recvmsg bugfix.
 *		Alan Cox	:	Started proper garbage collector
 *		Heiko EiBfeldt	:	Missing verify_area check
 *		Alan Cox	:	Started POSIXisms
 *		Andreas Schwab	:	Replace inode by dentry for proper
 *					reference counting
 *		Kirk Petersen	:	Made this a module
 *	    Christoph Rohland	:	Elegant non-blocking accept/connect algorithm.
 *					Lots of bug fixes.
 *	     Alexey Kuznetosv	:	Repaired (I hope) bugs introduces
 *					by above two patches.
 *	     Andrea Arcangeli	:	If possible we block in connect(2)
 *					if the max backlog of the listen socket
 *					is been reached. This won't break
 *					old apps and it will avoid huge amount
 *					of socks hashed (this for unix_gc()
 *					performances reasons).
 *					Security fix that limits the max
 *					number of socks to 2*max_files and
 *					the number of skb queueable in the
 *					dgram receiver.
 *		Artur Skawina   :	Hash function optimizations
 *	     Alexey Kuznetsov   :	Full scale SMP. Lot of bugs are introduced 8)
 *	      Malcolm Beattie   :	Set peercred for socketpair
 *	     Michal Ostrowski   :       Module initialization cleanup.
 *	     Arnaldo C. Melo	:	Remove MOD_{INC,DEC}_USE_COUNT,
 *	     				the core infrastructure is doing that
 *	     				for all net proto families now (2.5.69+)
 *
 *
 * Known differences from reference BSD that was tested:
 *
 *	[TO FIX]
 *	ECONNREFUSED is not returned from one end of a connected() socket to the
 *		other the moment one end closes.
 *	fstat() doesn't return st_dev=0, and give the blksize as high water mark
 *		and a fake inode identifier (nor the BSD first socket fstat twice bug).
 *	[NOT TO FIX]
 *	accept() returns a path name even if the connecting socket has closed
 *		in the meantime (BSD loses the path and gives up).
 *	accept() returns 0 length path for an unbound connector. BSD returns 16
 *		and a null first byte in the path (but not for gethost/peername - BSD bug ??)
 *	socketpair(...SOCK_RAW..) doesn't panic the kernel.
 *	BSD af_unix apparently has connect forgetting to block properly.
 *		(need to check this with the POSIX spec in detail)
 *
 * Differences from 2.0.0-11-... (ANK)
 *	Bug fixes and improvements.
 *		- client shutdown killed server socket.
 *		- removed all useless cli/sti pairs.
 *
 *	Semantic changes/extensions.
 *		- generic control message passing.
 *		- SCM_CREDENTIALS control message.
 *		- "Abstract" (not FS based) socket bindings.
 *		  Abstract names are sequences of bytes (not zero terminated)
 *		  started by 0, so that this name space does not intersect
 *		  with BSD names.
 */

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/fcntl.h>
#include <linux/termios.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
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#include <net/net_namespace.h>
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#include <net/sock.h>
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#include <net/tcp_states.h>
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#include <net/af_unix.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/scm.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/rtnetlink.h>
#include <linux/mount.h>
#include <net/checksum.h>
#include <linux/security.h>
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#include <linux/freezer.h>
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struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
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EXPORT_SYMBOL_GPL(unix_socket_table);
DEFINE_SPINLOCK(unix_table_lock);
EXPORT_SYMBOL_GPL(unix_table_lock);
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static atomic_long_t unix_nr_socks;
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static struct hlist_head *unix_sockets_unbound(void *addr)
{
	unsigned long hash = (unsigned long)addr;

	hash ^= hash >> 16;
	hash ^= hash >> 8;
	hash %= UNIX_HASH_SIZE;
	return &unix_socket_table[UNIX_HASH_SIZE + hash];
}

#define UNIX_ABSTRACT(sk)	(unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
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#ifdef CONFIG_SECURITY_NETWORK
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static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{
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	UNIXCB(skb).secid = scm->secid;
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}

static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
{
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	scm->secid = UNIXCB(skb).secid;
}

static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
{
	return (scm->secid == UNIXCB(skb).secid);
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}
#else
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static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{ }

static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
{ }
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static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
{
	return true;
}
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#endif /* CONFIG_SECURITY_NETWORK */

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/*
 *  SMP locking strategy:
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 *    hash table is protected with spinlock unix_table_lock
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 *    each socket state is protected by separate spin lock.
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 */

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static inline unsigned int unix_hash_fold(__wsum n)
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{
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	unsigned int hash = (__force unsigned int)csum_fold(n);
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	hash ^= hash>>8;
	return hash&(UNIX_HASH_SIZE-1);
}

#define unix_peer(sk) (unix_sk(sk)->peer)

static inline int unix_our_peer(struct sock *sk, struct sock *osk)
{
	return unix_peer(osk) == sk;
}

static inline int unix_may_send(struct sock *sk, struct sock *osk)
{
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	return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
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}

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static inline int unix_recvq_full(struct sock const *sk)
{
	return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
}

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struct sock *unix_peer_get(struct sock *s)
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{
	struct sock *peer;

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	unix_state_lock(s);
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	peer = unix_peer(s);
	if (peer)
		sock_hold(peer);
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	unix_state_unlock(s);
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	return peer;
}
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EXPORT_SYMBOL_GPL(unix_peer_get);
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static inline void unix_release_addr(struct unix_address *addr)
{
	if (atomic_dec_and_test(&addr->refcnt))
		kfree(addr);
}

/*
 *	Check unix socket name:
 *		- should be not zero length.
 *	        - if started by not zero, should be NULL terminated (FS object)
 *		- if started by zero, it is abstract name.
 */
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static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
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{
	if (len <= sizeof(short) || len > sizeof(*sunaddr))
		return -EINVAL;
	if (!sunaddr || sunaddr->sun_family != AF_UNIX)
		return -EINVAL;
	if (sunaddr->sun_path[0]) {
		/*
		 * This may look like an off by one error but it is a bit more
		 * subtle. 108 is the longest valid AF_UNIX path for a binding.
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		 * sun_path[108] doesn't as such exist.  However in kernel space
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		 * we are guaranteed that it is a valid memory location in our
		 * kernel address buffer.
		 */
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		((char *)sunaddr)[len] = 0;
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		len = strlen(sunaddr->sun_path)+1+sizeof(short);
		return len;
	}

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	*hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
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	return len;
}

static void __unix_remove_socket(struct sock *sk)
{
	sk_del_node_init(sk);
}

static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
{
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	WARN_ON(!sk_unhashed(sk));
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	sk_add_node(sk, list);
}

static inline void unix_remove_socket(struct sock *sk)
{
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	spin_lock(&unix_table_lock);
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	__unix_remove_socket(sk);
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	spin_unlock(&unix_table_lock);
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}

static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
{
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	spin_lock(&unix_table_lock);
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	__unix_insert_socket(list, sk);
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	spin_unlock(&unix_table_lock);
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}

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static struct sock *__unix_find_socket_byname(struct net *net,
					      struct sockaddr_un *sunname,
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					      int len, int type, unsigned int hash)
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{
	struct sock *s;

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	sk_for_each(s, &unix_socket_table[hash ^ type]) {
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		struct unix_sock *u = unix_sk(s);

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		if (!net_eq(sock_net(s), net))
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			continue;

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		if (u->addr->len == len &&
		    !memcmp(u->addr->name, sunname, len))
			goto found;
	}
	s = NULL;
found:
	return s;
}

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static inline struct sock *unix_find_socket_byname(struct net *net,
						   struct sockaddr_un *sunname,
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						   int len, int type,
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						   unsigned int hash)
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{
	struct sock *s;

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	spin_lock(&unix_table_lock);
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	s = __unix_find_socket_byname(net, sunname, len, type, hash);
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	if (s)
		sock_hold(s);
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	spin_unlock(&unix_table_lock);
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	return s;
}

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static struct sock *unix_find_socket_byinode(struct inode *i)
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{
	struct sock *s;

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	spin_lock(&unix_table_lock);
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	sk_for_each(s,
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		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
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		struct dentry *dentry = unix_sk(s)->path.dentry;
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		if (dentry && d_backing_inode(dentry) == i) {
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			sock_hold(s);
			goto found;
		}
	}
	s = NULL;
found:
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	spin_unlock(&unix_table_lock);
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	return s;
}

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static int unix_writable(const struct sock *sk)
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{
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	return sk->sk_state != TCP_LISTEN &&
	       (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
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}

static void unix_write_space(struct sock *sk)
{
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	struct socket_wq *wq;

	rcu_read_lock();
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	if (unix_writable(sk)) {
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		wq = rcu_dereference(sk->sk_wq);
		if (wq_has_sleeper(wq))
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			wake_up_interruptible_sync_poll(&wq->wait,
				POLLOUT | POLLWRNORM | POLLWRBAND);
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		sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
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	}
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	rcu_read_unlock();
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}

/* When dgram socket disconnects (or changes its peer), we clear its receive
 * queue of packets arrived from previous peer. First, it allows to do
 * flow control based only on wmem_alloc; second, sk connected to peer
 * may receive messages only from that peer. */
static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
{
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	if (!skb_queue_empty(&sk->sk_receive_queue)) {
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		skb_queue_purge(&sk->sk_receive_queue);
		wake_up_interruptible_all(&unix_sk(sk)->peer_wait);

		/* If one link of bidirectional dgram pipe is disconnected,
		 * we signal error. Messages are lost. Do not make this,
		 * when peer was not connected to us.
		 */
		if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
			other->sk_err = ECONNRESET;
			other->sk_error_report(other);
		}
	}
}

static void unix_sock_destructor(struct sock *sk)
{
	struct unix_sock *u = unix_sk(sk);

	skb_queue_purge(&sk->sk_receive_queue);

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	WARN_ON(atomic_read(&sk->sk_wmem_alloc));
	WARN_ON(!sk_unhashed(sk));
	WARN_ON(sk->sk_socket);
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	if (!sock_flag(sk, SOCK_DEAD)) {
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		pr_info("Attempt to release alive unix socket: %p\n", sk);
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		return;
	}

	if (u->addr)
		unix_release_addr(u->addr);

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	atomic_long_dec(&unix_nr_socks);
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	local_bh_disable();
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	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
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	local_bh_enable();
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#ifdef UNIX_REFCNT_DEBUG
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	pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
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		atomic_long_read(&unix_nr_socks));
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#endif
}

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static void unix_release_sock(struct sock *sk, int embrion)
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{
	struct unix_sock *u = unix_sk(sk);
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	struct path path;
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	struct sock *skpair;
	struct sk_buff *skb;
	int state;

	unix_remove_socket(sk);

	/* Clear state */
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	unix_state_lock(sk);
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	sock_orphan(sk);
	sk->sk_shutdown = SHUTDOWN_MASK;
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	path	     = u->path;
	u->path.dentry = NULL;
	u->path.mnt = NULL;
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	state = sk->sk_state;
	sk->sk_state = TCP_CLOSE;
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	unix_state_unlock(sk);
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	wake_up_interruptible_all(&u->peer_wait);

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	skpair = unix_peer(sk);
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	if (skpair != NULL) {
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		if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
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			unix_state_lock(skpair);
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			/* No more writes */
			skpair->sk_shutdown = SHUTDOWN_MASK;
			if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
				skpair->sk_err = ECONNRESET;
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			unix_state_unlock(skpair);
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			skpair->sk_state_change(skpair);
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			sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
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		}
		sock_put(skpair); /* It may now die */
		unix_peer(sk) = NULL;
	}

	/* Try to flush out this socket. Throw out buffers at least */

	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
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		if (state == TCP_LISTEN)
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			unix_release_sock(skb->sk, 1);
		/* passed fds are erased in the kfree_skb hook	      */
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		UNIXCB(skb).consumed = skb->len;
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		kfree_skb(skb);
	}

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	if (path.dentry)
		path_put(&path);
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	sock_put(sk);

	/* ---- Socket is dead now and most probably destroyed ---- */

	/*
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	 * Fixme: BSD difference: In BSD all sockets connected to us get
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	 *	  ECONNRESET and we die on the spot. In Linux we behave
	 *	  like files and pipes do and wait for the last
	 *	  dereference.
	 *
	 * Can't we simply set sock->err?
	 *
	 *	  What the above comment does talk about? --ANK(980817)
	 */

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	if (unix_tot_inflight)
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		unix_gc();		/* Garbage collect fds */
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}

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static void init_peercred(struct sock *sk)
{
	put_pid(sk->sk_peer_pid);
	if (sk->sk_peer_cred)
		put_cred(sk->sk_peer_cred);
	sk->sk_peer_pid  = get_pid(task_tgid(current));
	sk->sk_peer_cred = get_current_cred();
}

static void copy_peercred(struct sock *sk, struct sock *peersk)
{
	put_pid(sk->sk_peer_pid);
	if (sk->sk_peer_cred)
		put_cred(sk->sk_peer_cred);
	sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
	sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
}

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static int unix_listen(struct socket *sock, int backlog)
{
	int err;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
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	struct pid *old_pid = NULL;
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	err = -EOPNOTSUPP;
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	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
		goto out;	/* Only stream/seqpacket sockets accept */
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	err = -EINVAL;
	if (!u->addr)
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		goto out;	/* No listens on an unbound socket */
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	unix_state_lock(sk);
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	if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
		goto out_unlock;
	if (backlog > sk->sk_max_ack_backlog)
		wake_up_interruptible_all(&u->peer_wait);
	sk->sk_max_ack_backlog	= backlog;
	sk->sk_state		= TCP_LISTEN;
	/* set credentials so connect can copy them */
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	init_peercred(sk);
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	err = 0;

out_unlock:
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	unix_state_unlock(sk);
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	put_pid(old_pid);
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out:
	return err;
}

static int unix_release(struct socket *);
static int unix_bind(struct socket *, struct sockaddr *, int);
static int unix_stream_connect(struct socket *, struct sockaddr *,
			       int addr_len, int flags);
static int unix_socketpair(struct socket *, struct socket *);
static int unix_accept(struct socket *, struct socket *, int);
static int unix_getname(struct socket *, struct sockaddr *, int *, int);
static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
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static unsigned int unix_dgram_poll(struct file *, struct socket *,
				    poll_table *);
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static int unix_ioctl(struct socket *, unsigned int, unsigned long);
static int unix_shutdown(struct socket *, int);
531 532
static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
533 534
static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
				    size_t size, int flags);
535 536 537
static ssize_t unix_stream_splice_read(struct socket *,  loff_t *ppos,
				       struct pipe_inode_info *, size_t size,
				       unsigned int flags);
538 539
static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
L
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static int unix_dgram_connect(struct socket *, struct sockaddr *,
			      int, int);
542 543 544
static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
				  int);
L
Linus Torvalds 已提交
545

546
static int unix_set_peek_off(struct sock *sk, int val)
547 548 549
{
	struct unix_sock *u = unix_sk(sk);

550 551 552
	if (mutex_lock_interruptible(&u->readlock))
		return -EINTR;

553 554
	sk->sk_peek_off = val;
	mutex_unlock(&u->readlock);
555 556

	return 0;
557 558 559
}


560
static const struct proto_ops unix_stream_ops = {
L
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	.family =	PF_UNIX,
	.owner =	THIS_MODULE,
	.release =	unix_release,
	.bind =		unix_bind,
	.connect =	unix_stream_connect,
	.socketpair =	unix_socketpair,
	.accept =	unix_accept,
	.getname =	unix_getname,
	.poll =		unix_poll,
	.ioctl =	unix_ioctl,
	.listen =	unix_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_stream_sendmsg,
	.recvmsg =	unix_stream_recvmsg,
	.mmap =		sock_no_mmap,
578
	.sendpage =	unix_stream_sendpage,
579
	.splice_read =	unix_stream_splice_read,
580
	.set_peek_off =	unix_set_peek_off,
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};

583
static const struct proto_ops unix_dgram_ops = {
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	.family =	PF_UNIX,
	.owner =	THIS_MODULE,
	.release =	unix_release,
	.bind =		unix_bind,
	.connect =	unix_dgram_connect,
	.socketpair =	unix_socketpair,
	.accept =	sock_no_accept,
	.getname =	unix_getname,
592
	.poll =		unix_dgram_poll,
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	.ioctl =	unix_ioctl,
	.listen =	sock_no_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_dgram_sendmsg,
	.recvmsg =	unix_dgram_recvmsg,
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
602
	.set_peek_off =	unix_set_peek_off,
L
Linus Torvalds 已提交
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};

605
static const struct proto_ops unix_seqpacket_ops = {
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	.family =	PF_UNIX,
	.owner =	THIS_MODULE,
	.release =	unix_release,
	.bind =		unix_bind,
	.connect =	unix_stream_connect,
	.socketpair =	unix_socketpair,
	.accept =	unix_accept,
	.getname =	unix_getname,
614
	.poll =		unix_dgram_poll,
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	.ioctl =	unix_ioctl,
	.listen =	unix_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_seqpacket_sendmsg,
621
	.recvmsg =	unix_seqpacket_recvmsg,
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	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
624
	.set_peek_off =	unix_set_peek_off,
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};

static struct proto unix_proto = {
628 629 630
	.name			= "UNIX",
	.owner			= THIS_MODULE,
	.obj_size		= sizeof(struct unix_sock),
L
Linus Torvalds 已提交
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};

633 634 635 636 637 638 639 640
/*
 * AF_UNIX sockets do not interact with hardware, hence they
 * dont trigger interrupts - so it's safe for them to have
 * bh-unsafe locking for their sk_receive_queue.lock. Split off
 * this special lock-class by reinitializing the spinlock key:
 */
static struct lock_class_key af_unix_sk_receive_queue_lock_key;

641
static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
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{
	struct sock *sk = NULL;
	struct unix_sock *u;

E
Eric Dumazet 已提交
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	atomic_long_inc(&unix_nr_socks);
	if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
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		goto out;

650
	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
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	if (!sk)
		goto out;

E
Eric Dumazet 已提交
654
	sock_init_data(sock, sk);
655 656
	lockdep_set_class(&sk->sk_receive_queue.lock,
				&af_unix_sk_receive_queue_lock_key);
L
Linus Torvalds 已提交
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	sk->sk_write_space	= unix_write_space;
659
	sk->sk_max_ack_backlog	= net->unx.sysctl_max_dgram_qlen;
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	sk->sk_destruct		= unix_sock_destructor;
	u	  = unix_sk(sk);
A
Al Viro 已提交
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	u->path.dentry = NULL;
	u->path.mnt = NULL;
664
	spin_lock_init(&u->lock);
A
Al Viro 已提交
665
	atomic_long_set(&u->inflight, 0);
666
	INIT_LIST_HEAD(&u->link);
I
Ingo Molnar 已提交
667
	mutex_init(&u->readlock); /* single task reading lock */
L
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	init_waitqueue_head(&u->peer_wait);
E
Eric Dumazet 已提交
669
	unix_insert_socket(unix_sockets_unbound(sk), sk);
L
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670
out:
671
	if (sk == NULL)
E
Eric Dumazet 已提交
672
		atomic_long_dec(&unix_nr_socks);
673 674
	else {
		local_bh_disable();
675
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
676 677
		local_bh_enable();
	}
L
Linus Torvalds 已提交
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	return sk;
}

681 682
static int unix_create(struct net *net, struct socket *sock, int protocol,
		       int kern)
L
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683 684 685 686 687 688 689 690 691 692 693 694 695 696 697
{
	if (protocol && protocol != PF_UNIX)
		return -EPROTONOSUPPORT;

	sock->state = SS_UNCONNECTED;

	switch (sock->type) {
	case SOCK_STREAM:
		sock->ops = &unix_stream_ops;
		break;
		/*
		 *	Believe it or not BSD has AF_UNIX, SOCK_RAW though
		 *	nothing uses it.
		 */
	case SOCK_RAW:
698
		sock->type = SOCK_DGRAM;
L
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	case SOCK_DGRAM:
		sock->ops = &unix_dgram_ops;
		break;
	case SOCK_SEQPACKET:
		sock->ops = &unix_seqpacket_ops;
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

709
	return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
L
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710 711 712 713 714 715 716 717 718
}

static int unix_release(struct socket *sock)
{
	struct sock *sk = sock->sk;

	if (!sk)
		return 0;

719
	unix_release_sock(sk, 0);
L
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	sock->sk = NULL;

722
	return 0;
L
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723 724 725 726 727
}

static int unix_autobind(struct socket *sock)
{
	struct sock *sk = sock->sk;
728
	struct net *net = sock_net(sk);
L
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	struct unix_sock *u = unix_sk(sk);
	static u32 ordernum = 1;
E
Eric Dumazet 已提交
731
	struct unix_address *addr;
L
Linus Torvalds 已提交
732
	int err;
733
	unsigned int retries = 0;
L
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734

735 736 737
	err = mutex_lock_interruptible(&u->readlock);
	if (err)
		return err;
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738 739 740 741 742 743

	err = 0;
	if (u->addr)
		goto out;

	err = -ENOMEM;
744
	addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
L
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	if (!addr)
		goto out;

	addr->name->sun_family = AF_UNIX;
	atomic_set(&addr->refcnt, 1);

retry:
	addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
753
	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
L
Linus Torvalds 已提交
754

755
	spin_lock(&unix_table_lock);
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	ordernum = (ordernum+1)&0xFFFFF;

758
	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
L
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759
				      addr->hash)) {
760
		spin_unlock(&unix_table_lock);
761 762 763 764 765 766 767 768 769 770 771
		/*
		 * __unix_find_socket_byname() may take long time if many names
		 * are already in use.
		 */
		cond_resched();
		/* Give up if all names seems to be in use. */
		if (retries++ == 0xFFFFF) {
			err = -ENOSPC;
			kfree(addr);
			goto out;
		}
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		goto retry;
	}
	addr->hash ^= sk->sk_type;

	__unix_remove_socket(sk);
	u->addr = addr;
	__unix_insert_socket(&unix_socket_table[addr->hash], sk);
779
	spin_unlock(&unix_table_lock);
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	err = 0;

I
Ingo Molnar 已提交
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out:	mutex_unlock(&u->readlock);
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	return err;
}

786 787
static struct sock *unix_find_other(struct net *net,
				    struct sockaddr_un *sunname, int len,
788
				    int type, unsigned int hash, int *error)
L
Linus Torvalds 已提交
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{
	struct sock *u;
791
	struct path path;
L
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792
	int err = 0;
793

L
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	if (sunname->sun_path[0]) {
795 796
		struct inode *inode;
		err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
L
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		if (err)
			goto fail;
799
		inode = d_backing_inode(path.dentry);
800
		err = inode_permission(inode, MAY_WRITE);
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Linus Torvalds 已提交
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		if (err)
			goto put_fail;

		err = -ECONNREFUSED;
805
		if (!S_ISSOCK(inode->i_mode))
L
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			goto put_fail;
807
		u = unix_find_socket_byinode(inode);
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808 809 810 811
		if (!u)
			goto put_fail;

		if (u->sk_type == type)
A
Al Viro 已提交
812
			touch_atime(&path);
L
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813

814
		path_put(&path);
L
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815

816
		err = -EPROTOTYPE;
L
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		if (u->sk_type != type) {
			sock_put(u);
			goto fail;
		}
	} else {
		err = -ECONNREFUSED;
823
		u = unix_find_socket_byname(net, sunname, len, type, hash);
L
Linus Torvalds 已提交
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		if (u) {
			struct dentry *dentry;
A
Al Viro 已提交
826
			dentry = unix_sk(u)->path.dentry;
L
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			if (dentry)
A
Al Viro 已提交
828
				touch_atime(&unix_sk(u)->path);
L
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		} else
			goto fail;
	}
	return u;

put_fail:
835
	path_put(&path);
L
Linus Torvalds 已提交
836
fail:
837
	*error = err;
L
Linus Torvalds 已提交
838 839 840
	return NULL;
}

A
Al Viro 已提交
841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859
static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
{
	struct dentry *dentry;
	struct path path;
	int err = 0;
	/*
	 * Get the parent directory, calculate the hash for last
	 * component.
	 */
	dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
	err = PTR_ERR(dentry);
	if (IS_ERR(dentry))
		return err;

	/*
	 * All right, let's create it.
	 */
	err = security_path_mknod(&path, dentry, mode, 0);
	if (!err) {
860
		err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
A
Al Viro 已提交
861 862 863 864 865 866 867 868
		if (!err) {
			res->mnt = mntget(path.mnt);
			res->dentry = dget(dentry);
		}
	}
	done_path_create(&path, dentry);
	return err;
}
L
Linus Torvalds 已提交
869 870 871 872

static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sock *sk = sock->sk;
873
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
874
	struct unix_sock *u = unix_sk(sk);
875
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
876
	char *sun_path = sunaddr->sun_path;
L
Linus Torvalds 已提交
877
	int err;
878
	unsigned int hash;
L
Linus Torvalds 已提交
879 880 881 882 883 884 885
	struct unix_address *addr;
	struct hlist_head *list;

	err = -EINVAL;
	if (sunaddr->sun_family != AF_UNIX)
		goto out;

886
	if (addr_len == sizeof(short)) {
L
Linus Torvalds 已提交
887 888 889 890 891 892 893 894 895
		err = unix_autobind(sock);
		goto out;
	}

	err = unix_mkname(sunaddr, addr_len, &hash);
	if (err < 0)
		goto out;
	addr_len = err;

896 897 898
	err = mutex_lock_interruptible(&u->readlock);
	if (err)
		goto out;
L
Linus Torvalds 已提交
899 900 901 902 903 904 905 906 907 908 909 910 911 912 913

	err = -EINVAL;
	if (u->addr)
		goto out_up;

	err = -ENOMEM;
	addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
	if (!addr)
		goto out_up;

	memcpy(addr->name, sunaddr, addr_len);
	addr->len = addr_len;
	addr->hash = hash ^ sk->sk_type;
	atomic_set(&addr->refcnt, 1);

914
	if (sun_path[0]) {
A
Al Viro 已提交
915 916
		struct path path;
		umode_t mode = S_IFSOCK |
A
Al Viro 已提交
917
		       (SOCK_INODE(sock)->i_mode & ~current_umask());
A
Al Viro 已提交
918 919 920 921 922 923 924
		err = unix_mknod(sun_path, mode, &path);
		if (err) {
			if (err == -EEXIST)
				err = -EADDRINUSE;
			unix_release_addr(addr);
			goto out_up;
		}
L
Linus Torvalds 已提交
925
		addr->hash = UNIX_HASH_SIZE;
926
		hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE-1);
A
Al Viro 已提交
927 928 929 930 931
		spin_lock(&unix_table_lock);
		u->path = path;
		list = &unix_socket_table[hash];
	} else {
		spin_lock(&unix_table_lock);
L
Linus Torvalds 已提交
932
		err = -EADDRINUSE;
933
		if (__unix_find_socket_byname(net, sunaddr, addr_len,
L
Linus Torvalds 已提交
934 935 936 937 938 939 940 941 942 943 944 945 946 947
					      sk->sk_type, hash)) {
			unix_release_addr(addr);
			goto out_unlock;
		}

		list = &unix_socket_table[addr->hash];
	}

	err = 0;
	__unix_remove_socket(sk);
	u->addr = addr;
	__unix_insert_socket(list, sk);

out_unlock:
948
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
949
out_up:
I
Ingo Molnar 已提交
950
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
951 952 953 954
out:
	return err;
}

955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979
static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
{
	if (unlikely(sk1 == sk2) || !sk2) {
		unix_state_lock(sk1);
		return;
	}
	if (sk1 < sk2) {
		unix_state_lock(sk1);
		unix_state_lock_nested(sk2);
	} else {
		unix_state_lock(sk2);
		unix_state_lock_nested(sk1);
	}
}

static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
{
	if (unlikely(sk1 == sk2) || !sk2) {
		unix_state_unlock(sk1);
		return;
	}
	unix_state_unlock(sk1);
	unix_state_unlock(sk2);
}

L
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980 981 982 983
static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
			      int alen, int flags)
{
	struct sock *sk = sock->sk;
984
	struct net *net = sock_net(sk);
985
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
L
Linus Torvalds 已提交
986
	struct sock *other;
987
	unsigned int hash;
L
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988 989 990 991 992 993 994 995 996 997 998 999
	int err;

	if (addr->sa_family != AF_UNSPEC) {
		err = unix_mkname(sunaddr, alen, &hash);
		if (err < 0)
			goto out;
		alen = err;

		if (test_bit(SOCK_PASSCRED, &sock->flags) &&
		    !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
			goto out;

1000
restart:
1001
		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
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1002 1003 1004
		if (!other)
			goto out;

1005 1006 1007 1008 1009 1010 1011 1012
		unix_state_double_lock(sk, other);

		/* Apparently VFS overslept socket death. Retry. */
		if (sock_flag(other, SOCK_DEAD)) {
			unix_state_double_unlock(sk, other);
			sock_put(other);
			goto restart;
		}
L
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1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026

		err = -EPERM;
		if (!unix_may_send(sk, other))
			goto out_unlock;

		err = security_unix_may_send(sk->sk_socket, other->sk_socket);
		if (err)
			goto out_unlock;

	} else {
		/*
		 *	1003.1g breaking connected state with AF_UNSPEC
		 */
		other = NULL;
1027
		unix_state_double_lock(sk, other);
L
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1028 1029 1030 1031 1032 1033 1034
	}

	/*
	 * If it was connected, reconnect.
	 */
	if (unix_peer(sk)) {
		struct sock *old_peer = unix_peer(sk);
1035
		unix_peer(sk) = other;
1036
		unix_state_double_unlock(sk, other);
L
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1037 1038 1039 1040 1041

		if (other != old_peer)
			unix_dgram_disconnected(sk, old_peer);
		sock_put(old_peer);
	} else {
1042
		unix_peer(sk) = other;
1043
		unix_state_double_unlock(sk, other);
L
Linus Torvalds 已提交
1044
	}
1045
	return 0;
L
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1046 1047

out_unlock:
1048
	unix_state_double_unlock(sk, other);
L
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1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063
	sock_put(other);
out:
	return err;
}

static long unix_wait_for_peer(struct sock *other, long timeo)
{
	struct unix_sock *u = unix_sk(other);
	int sched;
	DEFINE_WAIT(wait);

	prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);

	sched = !sock_flag(other, SOCK_DEAD) &&
		!(other->sk_shutdown & RCV_SHUTDOWN) &&
1064
		unix_recvq_full(other);
L
Linus Torvalds 已提交
1065

1066
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077

	if (sched)
		timeo = schedule_timeout(timeo);

	finish_wait(&u->peer_wait, &wait);
	return timeo;
}

static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
			       int addr_len, int flags)
{
1078
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
L
Linus Torvalds 已提交
1079
	struct sock *sk = sock->sk;
1080
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1081 1082 1083 1084
	struct unix_sock *u = unix_sk(sk), *newu, *otheru;
	struct sock *newsk = NULL;
	struct sock *other = NULL;
	struct sk_buff *skb = NULL;
1085
	unsigned int hash;
L
Linus Torvalds 已提交
1086 1087 1088 1089 1090 1091 1092 1093 1094
	int st;
	int err;
	long timeo;

	err = unix_mkname(sunaddr, addr_len, &hash);
	if (err < 0)
		goto out;
	addr_len = err;

1095 1096
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
	    (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108
		goto out;

	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);

	/* First of all allocate resources.
	   If we will make it after state is locked,
	   we will have to recheck all again in any case.
	 */

	err = -ENOMEM;

	/* create new sock for complete connection */
1109
	newsk = unix_create1(sock_net(sk), NULL, 0);
L
Linus Torvalds 已提交
1110 1111 1112 1113 1114 1115 1116 1117 1118 1119
	if (newsk == NULL)
		goto out;

	/* Allocate skb for sending to listening sock */
	skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
	if (skb == NULL)
		goto out;

restart:
	/*  Find listening sock. */
1120
	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
L
Linus Torvalds 已提交
1121 1122 1123 1124
	if (!other)
		goto out;

	/* Latch state of peer */
1125
	unix_state_lock(other);
L
Linus Torvalds 已提交
1126 1127 1128

	/* Apparently VFS overslept socket death. Retry. */
	if (sock_flag(other, SOCK_DEAD)) {
1129
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1130 1131 1132 1133 1134 1135 1136
		sock_put(other);
		goto restart;
	}

	err = -ECONNREFUSED;
	if (other->sk_state != TCP_LISTEN)
		goto out_unlock;
1137 1138
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;
L
Linus Torvalds 已提交
1139

1140
	if (unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
		err = -EAGAIN;
		if (!timeo)
			goto out_unlock;

		timeo = unix_wait_for_peer(other, timeo);

		err = sock_intr_errno(timeo);
		if (signal_pending(current))
			goto out;
		sock_put(other);
		goto restart;
1152
	}
L
Linus Torvalds 已提交
1153 1154 1155

	/* Latch our state.

D
Daniel Baluta 已提交
1156
	   It is tricky place. We need to grab our state lock and cannot
L
Linus Torvalds 已提交
1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179
	   drop lock on peer. It is dangerous because deadlock is
	   possible. Connect to self case and simultaneous
	   attempt to connect are eliminated by checking socket
	   state. other is TCP_LISTEN, if sk is TCP_LISTEN we
	   check this before attempt to grab lock.

	   Well, and we have to recheck the state after socket locked.
	 */
	st = sk->sk_state;

	switch (st) {
	case TCP_CLOSE:
		/* This is ok... continue with connect */
		break;
	case TCP_ESTABLISHED:
		/* Socket is already connected */
		err = -EISCONN;
		goto out_unlock;
	default:
		err = -EINVAL;
		goto out_unlock;
	}

1180
	unix_state_lock_nested(sk);
L
Linus Torvalds 已提交
1181 1182

	if (sk->sk_state != st) {
1183 1184
		unix_state_unlock(sk);
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1185 1186 1187 1188
		sock_put(other);
		goto restart;
	}

1189
	err = security_unix_stream_connect(sk, other, newsk);
L
Linus Torvalds 已提交
1190
	if (err) {
1191
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1192 1193 1194 1195 1196 1197 1198 1199 1200
		goto out_unlock;
	}

	/* The way is open! Fastly set all the necessary fields... */

	sock_hold(sk);
	unix_peer(newsk)	= sk;
	newsk->sk_state		= TCP_ESTABLISHED;
	newsk->sk_type		= sk->sk_type;
1201
	init_peercred(newsk);
L
Linus Torvalds 已提交
1202
	newu = unix_sk(newsk);
1203
	RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
L
Linus Torvalds 已提交
1204 1205 1206 1207 1208 1209 1210
	otheru = unix_sk(other);

	/* copy address information from listening to new sock*/
	if (otheru->addr) {
		atomic_inc(&otheru->addr->refcnt);
		newu->addr = otheru->addr;
	}
A
Al Viro 已提交
1211 1212 1213
	if (otheru->path.dentry) {
		path_get(&otheru->path);
		newu->path = otheru->path;
L
Linus Torvalds 已提交
1214 1215 1216
	}

	/* Set credentials */
1217
	copy_peercred(sk, other);
L
Linus Torvalds 已提交
1218 1219 1220

	sock->state	= SS_CONNECTED;
	sk->sk_state	= TCP_ESTABLISHED;
1221 1222
	sock_hold(newsk);

1223
	smp_mb__after_atomic();	/* sock_hold() does an atomic_inc() */
1224
	unix_peer(sk)	= newsk;
L
Linus Torvalds 已提交
1225

1226
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1227 1228 1229 1230 1231

	/* take ten and and send info to listening sock */
	spin_lock(&other->sk_receive_queue.lock);
	__skb_queue_tail(&other->sk_receive_queue, skb);
	spin_unlock(&other->sk_receive_queue.lock);
1232
	unix_state_unlock(other);
1233
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1234 1235 1236 1237 1238
	sock_put(other);
	return 0;

out_unlock:
	if (other)
1239
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1240 1241

out:
1242
	kfree_skb(skb);
L
Linus Torvalds 已提交
1243 1244 1245 1246 1247 1248 1249 1250 1251
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
1252
	struct sock *ska = socka->sk, *skb = sockb->sk;
L
Linus Torvalds 已提交
1253 1254 1255 1256

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
1257 1258
	unix_peer(ska) = skb;
	unix_peer(skb) = ska;
1259 1260
	init_peercred(ska);
	init_peercred(skb);
L
Linus Torvalds 已提交
1261 1262 1263 1264 1265 1266 1267 1268 1269 1270

	if (ska->sk_type != SOCK_DGRAM) {
		ska->sk_state = TCP_ESTABLISHED;
		skb->sk_state = TCP_ESTABLISHED;
		socka->state  = SS_CONNECTED;
		sockb->state  = SS_CONNECTED;
	}
	return 0;
}

1271 1272 1273 1274 1275 1276 1277 1278 1279
static void unix_sock_inherit_flags(const struct socket *old,
				    struct socket *new)
{
	if (test_bit(SOCK_PASSCRED, &old->flags))
		set_bit(SOCK_PASSCRED, &new->flags);
	if (test_bit(SOCK_PASSSEC, &old->flags))
		set_bit(SOCK_PASSSEC, &new->flags);
}

L
Linus Torvalds 已提交
1280 1281 1282 1283 1284 1285 1286 1287
static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct sock *sk = sock->sk;
	struct sock *tsk;
	struct sk_buff *skb;
	int err;

	err = -EOPNOTSUPP;
E
Eric Dumazet 已提交
1288
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
L
Linus Torvalds 已提交
1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311
		goto out;

	err = -EINVAL;
	if (sk->sk_state != TCP_LISTEN)
		goto out;

	/* If socket state is TCP_LISTEN it cannot change (for now...),
	 * so that no locks are necessary.
	 */

	skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
	if (!skb) {
		/* This means receive shutdown. */
		if (err == 0)
			err = -EINVAL;
		goto out;
	}

	tsk = skb->sk;
	skb_free_datagram(sk, skb);
	wake_up_interruptible(&unix_sk(sk)->peer_wait);

	/* attach accepted sock to socket */
1312
	unix_state_lock(tsk);
L
Linus Torvalds 已提交
1313
	newsock->state = SS_CONNECTED;
1314
	unix_sock_inherit_flags(sock, newsock);
L
Linus Torvalds 已提交
1315
	sock_graft(tsk, newsock);
1316
	unix_state_unlock(tsk);
L
Linus Torvalds 已提交
1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327
	return 0;

out:
	return err;
}


static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
{
	struct sock *sk = sock->sk;
	struct unix_sock *u;
1328
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
L
Linus Torvalds 已提交
1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342
	int err = 0;

	if (peer) {
		sk = unix_peer_get(sk);

		err = -ENOTCONN;
		if (!sk)
			goto out;
		err = 0;
	} else {
		sock_hold(sk);
	}

	u = unix_sk(sk);
1343
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353
	if (!u->addr) {
		sunaddr->sun_family = AF_UNIX;
		sunaddr->sun_path[0] = 0;
		*uaddr_len = sizeof(short);
	} else {
		struct unix_address *addr = u->addr;

		*uaddr_len = addr->len;
		memcpy(sunaddr, addr->name, *uaddr_len);
	}
1354
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366
	sock_put(sk);
out:
	return err;
}

static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
{
	int i;

	scm->fp = UNIXCB(skb).fp;
	UNIXCB(skb).fp = NULL;

E
Eric Dumazet 已提交
1367
	for (i = scm->fp->count-1; i >= 0; i--)
L
Linus Torvalds 已提交
1368 1369 1370
		unix_notinflight(scm->fp->fp[i]);
}

1371
static void unix_destruct_scm(struct sk_buff *skb)
L
Linus Torvalds 已提交
1372 1373 1374
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
1375 1376 1377
	scm.pid  = UNIXCB(skb).pid;
	if (UNIXCB(skb).fp)
		unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
1378 1379 1380 1381 1382 1383 1384

	/* Alas, it calls VFS */
	/* So fscking what? fput() had been SMP-safe since the last Summer */
	scm_destroy(&scm);
	sock_wfree(skb);
}

E
Eric Dumazet 已提交
1385 1386
#define MAX_RECURSION_LEVEL 4

1387
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
L
Linus Torvalds 已提交
1388 1389
{
	int i;
E
Eric Dumazet 已提交
1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
	unsigned char max_level = 0;
	int unix_sock_count = 0;

	for (i = scm->fp->count - 1; i >= 0; i--) {
		struct sock *sk = unix_get_socket(scm->fp->fp[i]);

		if (sk) {
			unix_sock_count++;
			max_level = max(max_level,
					unix_sk(sk)->recursion_level);
		}
	}
	if (unlikely(max_level > MAX_RECURSION_LEVEL))
		return -ETOOMANYREFS;
1404 1405 1406 1407 1408 1409 1410 1411 1412 1413

	/*
	 * Need to duplicate file references for the sake of garbage
	 * collection.  Otherwise a socket in the fps might become a
	 * candidate for GC while the skb is not yet queued.
	 */
	UNIXCB(skb).fp = scm_fp_dup(scm->fp);
	if (!UNIXCB(skb).fp)
		return -ENOMEM;

E
Eric Dumazet 已提交
1414 1415 1416 1417 1418
	if (unix_sock_count) {
		for (i = scm->fp->count - 1; i >= 0; i--)
			unix_inflight(scm->fp->fp[i]);
	}
	return max_level;
L
Linus Torvalds 已提交
1419 1420
}

1421
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1422 1423
{
	int err = 0;
1424

1425
	UNIXCB(skb).pid  = get_pid(scm->pid);
1426 1427
	UNIXCB(skb).uid = scm->creds.uid;
	UNIXCB(skb).gid = scm->creds.gid;
1428
	UNIXCB(skb).fp = NULL;
1429
	unix_get_secdata(scm, skb);
1430 1431 1432 1433 1434 1435 1436
	if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

	skb->destructor = unix_destruct_scm;
	return err;
}

1437 1438 1439 1440 1441 1442 1443 1444
/*
 * Some apps rely on write() giving SCM_CREDENTIALS
 * We include credentials if source or destination socket
 * asserted SOCK_PASSCRED.
 */
static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
			    const struct sock *other)
{
1445
	if (UNIXCB(skb).pid)
1446 1447
		return;
	if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1448 1449
	    !other->sk_socket ||
	    test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1450
		UNIXCB(skb).pid  = get_pid(task_tgid(current));
1451
		current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1452 1453 1454
	}
}

L
Linus Torvalds 已提交
1455 1456 1457 1458
/*
 *	Send AF_UNIX data.
 */

1459 1460
static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
			      size_t len)
L
Linus Torvalds 已提交
1461 1462
{
	struct sock *sk = sock->sk;
1463
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1464
	struct unix_sock *u = unix_sk(sk);
1465
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
L
Linus Torvalds 已提交
1466 1467 1468
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
1469
	unsigned int hash;
1470
	struct sk_buff *skb;
L
Linus Torvalds 已提交
1471
	long timeo;
C
Christoph Hellwig 已提交
1472
	struct scm_cookie scm;
E
Eric Dumazet 已提交
1473
	int max_level;
1474
	int data_len = 0;
L
Linus Torvalds 已提交
1475

1476
	wait_for_unix_gc();
C
Christoph Hellwig 已提交
1477
	err = scm_send(sock, msg, &scm, false);
L
Linus Torvalds 已提交
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497
	if (err < 0)
		return err;

	err = -EOPNOTSUPP;
	if (msg->msg_flags&MSG_OOB)
		goto out;

	if (msg->msg_namelen) {
		err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
		if (err < 0)
			goto out;
		namelen = err;
	} else {
		sunaddr = NULL;
		err = -ENOTCONN;
		other = unix_peer_get(sk);
		if (!other)
			goto out;
	}

1498 1499
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
	    && (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1500 1501 1502 1503 1504 1505
		goto out;

	err = -EMSGSIZE;
	if (len > sk->sk_sndbuf - 32)
		goto out;

1506
	if (len > SKB_MAX_ALLOC) {
1507 1508 1509
		data_len = min_t(size_t,
				 len - SKB_MAX_ALLOC,
				 MAX_SKB_FRAGS * PAGE_SIZE);
1510 1511 1512 1513
		data_len = PAGE_ALIGN(data_len);

		BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
	}
1514 1515

	skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1516 1517
				   msg->msg_flags & MSG_DONTWAIT, &err,
				   PAGE_ALLOC_COSTLY_ORDER);
1518
	if (skb == NULL)
L
Linus Torvalds 已提交
1519 1520
		goto out;

C
Christoph Hellwig 已提交
1521
	err = unix_scm_to_skb(&scm, skb, true);
E
Eric Dumazet 已提交
1522
	if (err < 0)
1523
		goto out_free;
E
Eric Dumazet 已提交
1524
	max_level = err + 1;
C
Catherine Zhang 已提交
1525

1526 1527 1528
	skb_put(skb, len - data_len);
	skb->data_len = data_len;
	skb->len = len;
A
Al Viro 已提交
1529
	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
L
Linus Torvalds 已提交
1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540
	if (err)
		goto out_free;

	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);

restart:
	if (!other) {
		err = -ECONNRESET;
		if (sunaddr == NULL)
			goto out_free;

1541
		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
L
Linus Torvalds 已提交
1542
					hash, &err);
1543
		if (other == NULL)
L
Linus Torvalds 已提交
1544 1545 1546
			goto out_free;
	}

A
Alban Crequy 已提交
1547 1548 1549 1550 1551 1552
	if (sk_filter(other, skb) < 0) {
		/* Toss the packet but do not return any error to the sender */
		err = len;
		goto out_free;
	}

1553
	unix_state_lock(other);
L
Linus Torvalds 已提交
1554 1555 1556 1557 1558 1559 1560 1561 1562
	err = -EPERM;
	if (!unix_may_send(sk, other))
		goto out_unlock;

	if (sock_flag(other, SOCK_DEAD)) {
		/*
		 *	Check with 1003.1g - what should
		 *	datagram error
		 */
1563
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1564 1565 1566
		sock_put(other);

		err = 0;
1567
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1568
		if (unix_peer(sk) == other) {
1569
			unix_peer(sk) = NULL;
1570
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1571 1572 1573 1574 1575

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
1576
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594
		}

		other = NULL;
		if (err)
			goto out_free;
		goto restart;
	}

	err = -EPIPE;
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;

	if (sk->sk_type != SOCK_SEQPACKET) {
		err = security_unix_may_send(sk->sk_socket, other->sk_socket);
		if (err)
			goto out_unlock;
	}

1595
	if (unix_peer(other) != sk && unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609
		if (!timeo) {
			err = -EAGAIN;
			goto out_unlock;
		}

		timeo = unix_wait_for_peer(other, timeo);

		err = sock_intr_errno(timeo);
		if (signal_pending(current))
			goto out_free;

		goto restart;
	}

1610 1611
	if (sock_flag(other, SOCK_RCVTSTAMP))
		__net_timestamp(skb);
1612
	maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1613
	skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1614 1615
	if (max_level > unix_sk(other)->recursion_level)
		unix_sk(other)->recursion_level = max_level;
1616
	unix_state_unlock(other);
1617
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1618
	sock_put(other);
C
Christoph Hellwig 已提交
1619
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1620 1621 1622
	return len;

out_unlock:
1623
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1624 1625 1626 1627 1628
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
C
Christoph Hellwig 已提交
1629
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1630 1631 1632
	return err;
}

1633 1634 1635 1636
/* We use paged skbs for stream sockets, and limit occupancy to 32768
 * bytes, and a minimun of a full page.
 */
#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1637

1638 1639
static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
			       size_t len)
L
Linus Torvalds 已提交
1640 1641 1642
{
	struct sock *sk = sock->sk;
	struct sock *other = NULL;
E
Eric Dumazet 已提交
1643
	int err, size;
1644
	struct sk_buff *skb;
1645
	int sent = 0;
C
Christoph Hellwig 已提交
1646
	struct scm_cookie scm;
1647
	bool fds_sent = false;
E
Eric Dumazet 已提交
1648
	int max_level;
1649
	int data_len;
L
Linus Torvalds 已提交
1650

1651
	wait_for_unix_gc();
C
Christoph Hellwig 已提交
1652
	err = scm_send(sock, msg, &scm, false);
L
Linus Torvalds 已提交
1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664
	if (err < 0)
		return err;

	err = -EOPNOTSUPP;
	if (msg->msg_flags&MSG_OOB)
		goto out_err;

	if (msg->msg_namelen) {
		err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
		goto out_err;
	} else {
		err = -ENOTCONN;
1665
		other = unix_peer(sk);
L
Linus Torvalds 已提交
1666 1667 1668 1669 1670 1671 1672
		if (!other)
			goto out_err;
	}

	if (sk->sk_shutdown & SEND_SHUTDOWN)
		goto pipe_err;

E
Eric Dumazet 已提交
1673
	while (sent < len) {
1674
		size = len - sent;
L
Linus Torvalds 已提交
1675 1676

		/* Keep two messages in the pipe so it schedules better */
1677
		size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
L
Linus Torvalds 已提交
1678

1679 1680
		/* allow fallback to order-0 allocations */
		size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1681

1682
		data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
L
Linus Torvalds 已提交
1683

1684 1685
		data_len = min_t(size_t, size, PAGE_ALIGN(data_len));

1686
		skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1687 1688
					   msg->msg_flags & MSG_DONTWAIT, &err,
					   get_order(UNIX_SKB_FRAGS_SZ));
1689
		if (!skb)
L
Linus Torvalds 已提交
1690 1691
			goto out_err;

1692
		/* Only send the fds in the first buffer */
C
Christoph Hellwig 已提交
1693
		err = unix_scm_to_skb(&scm, skb, !fds_sent);
E
Eric Dumazet 已提交
1694
		if (err < 0) {
1695
			kfree_skb(skb);
1696
			goto out_err;
1697
		}
E
Eric Dumazet 已提交
1698
		max_level = err + 1;
1699
		fds_sent = true;
L
Linus Torvalds 已提交
1700

1701 1702 1703
		skb_put(skb, size - data_len);
		skb->data_len = data_len;
		skb->len = size;
A
Al Viro 已提交
1704
		err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
E
Eric Dumazet 已提交
1705
		if (err) {
L
Linus Torvalds 已提交
1706
			kfree_skb(skb);
1707
			goto out_err;
L
Linus Torvalds 已提交
1708 1709
		}

1710
		unix_state_lock(other);
L
Linus Torvalds 已提交
1711 1712 1713 1714 1715

		if (sock_flag(other, SOCK_DEAD) ||
		    (other->sk_shutdown & RCV_SHUTDOWN))
			goto pipe_err_free;

1716
		maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1717
		skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1718 1719
		if (max_level > unix_sk(other)->recursion_level)
			unix_sk(other)->recursion_level = max_level;
1720
		unix_state_unlock(other);
1721
		other->sk_data_ready(other);
1722
		sent += size;
L
Linus Torvalds 已提交
1723 1724
	}

C
Christoph Hellwig 已提交
1725
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1726 1727 1728 1729

	return sent;

pipe_err_free:
1730
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1731 1732
	kfree_skb(skb);
pipe_err:
E
Eric Dumazet 已提交
1733 1734
	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
L
Linus Torvalds 已提交
1735 1736
	err = -EPIPE;
out_err:
C
Christoph Hellwig 已提交
1737
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1738 1739 1740
	return sent ? : err;
}

1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802
static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
				    int offset, size_t size, int flags)
{
	int err = 0;
	bool send_sigpipe = true;
	struct sock *other, *sk = socket->sk;
	struct sk_buff *skb, *newskb = NULL, *tail = NULL;

	if (flags & MSG_OOB)
		return -EOPNOTSUPP;

	other = unix_peer(sk);
	if (!other || sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

	if (false) {
alloc_skb:
		unix_state_unlock(other);
		mutex_unlock(&unix_sk(other)->readlock);
		newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
					      &err, 0);
		if (!newskb)
			return err;
	}

	/* we must acquire readlock as we modify already present
	 * skbs in the sk_receive_queue and mess with skb->len
	 */
	err = mutex_lock_interruptible(&unix_sk(other)->readlock);
	if (err) {
		err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
		send_sigpipe = false;
		goto err;
	}

	if (sk->sk_shutdown & SEND_SHUTDOWN) {
		err = -EPIPE;
		goto err_unlock;
	}

	unix_state_lock(other);

	if (sock_flag(other, SOCK_DEAD) ||
	    other->sk_shutdown & RCV_SHUTDOWN) {
		err = -EPIPE;
		goto err_state_unlock;
	}

	skb = skb_peek_tail(&other->sk_receive_queue);
	if (tail && tail == skb) {
		skb = newskb;
	} else if (!skb) {
		if (newskb)
			skb = newskb;
		else
			goto alloc_skb;
	} else if (newskb) {
		/* this is fast path, we don't necessarily need to
		 * call to kfree_skb even though with newskb == NULL
		 * this - does no harm
		 */
		consume_skb(newskb);
1803
		newskb = NULL;
1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836
	}

	if (skb_append_pagefrags(skb, page, offset, size)) {
		tail = skb;
		goto alloc_skb;
	}

	skb->len += size;
	skb->data_len += size;
	skb->truesize += size;
	atomic_add(size, &sk->sk_wmem_alloc);

	if (newskb)
		__skb_queue_tail(&other->sk_receive_queue, newskb);

	unix_state_unlock(other);
	mutex_unlock(&unix_sk(other)->readlock);

	other->sk_data_ready(other);

	return size;

err_state_unlock:
	unix_state_unlock(other);
err_unlock:
	mutex_unlock(&unix_sk(other)->readlock);
err:
	kfree_skb(newskb);
	if (send_sigpipe && !(flags & MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
	return err;
}

1837 1838
static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
				  size_t len)
L
Linus Torvalds 已提交
1839 1840 1841
{
	int err;
	struct sock *sk = sock->sk;
1842

L
Linus Torvalds 已提交
1843 1844 1845 1846 1847 1848 1849 1850 1851 1852
	err = sock_error(sk);
	if (err)
		return err;

	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

	if (msg->msg_namelen)
		msg->msg_namelen = 0;

1853
	return unix_dgram_sendmsg(sock, msg, len);
L
Linus Torvalds 已提交
1854
}
1855

1856 1857
static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
				  size_t size, int flags)
1858 1859 1860 1861 1862 1863
{
	struct sock *sk = sock->sk;

	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

1864
	return unix_dgram_recvmsg(sock, msg, size, flags);
1865 1866
}

L
Linus Torvalds 已提交
1867 1868 1869 1870 1871 1872 1873 1874 1875 1876
static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
{
	struct unix_sock *u = unix_sk(sk);

	if (u->addr) {
		msg->msg_namelen = u->addr->len;
		memcpy(msg->msg_name, u->addr->name, u->addr->len);
	}
}

1877 1878
static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
			      size_t size, int flags)
L
Linus Torvalds 已提交
1879
{
C
Christoph Hellwig 已提交
1880
	struct scm_cookie scm;
L
Linus Torvalds 已提交
1881 1882 1883 1884 1885
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
	int noblock = flags & MSG_DONTWAIT;
	struct sk_buff *skb;
	int err;
1886
	int peeked, skip;
L
Linus Torvalds 已提交
1887 1888 1889 1890 1891

	err = -EOPNOTSUPP;
	if (flags&MSG_OOB)
		goto out;

1892
	err = mutex_lock_interruptible(&u->readlock);
1893 1894 1895 1896 1897
	if (unlikely(err)) {
		/* recvmsg() in non blocking mode is supposed to return -EAGAIN
		 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
		 */
		err = noblock ? -EAGAIN : -ERESTARTSYS;
1898 1899
		goto out;
	}
L
Linus Torvalds 已提交
1900

1901 1902 1903
	skip = sk_peek_offset(sk, flags);

	skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1904 1905 1906 1907 1908 1909 1910
	if (!skb) {
		unix_state_lock(sk);
		/* Signal EOF on disconnected non-blocking SEQPACKET socket. */
		if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
		    (sk->sk_shutdown & RCV_SHUTDOWN))
			err = 0;
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1911
		goto out_unlock;
1912
	}
L
Linus Torvalds 已提交
1913

E
Eric Dumazet 已提交
1914 1915
	wake_up_interruptible_sync_poll(&u->peer_wait,
					POLLOUT | POLLWRNORM | POLLWRBAND);
L
Linus Torvalds 已提交
1916 1917 1918 1919

	if (msg->msg_name)
		unix_copy_addr(msg, skb->sk);

1920 1921 1922
	if (size > skb->len - skip)
		size = skb->len - skip;
	else if (size < skb->len - skip)
L
Linus Torvalds 已提交
1923 1924
		msg->msg_flags |= MSG_TRUNC;

1925
	err = skb_copy_datagram_msg(skb, skip, msg, size);
L
Linus Torvalds 已提交
1926 1927 1928
	if (err)
		goto out_free;

1929 1930 1931
	if (sock_flag(sk, SOCK_RCVTSTAMP))
		__sock_recv_timestamp(msg, sk, skb);

C
Christoph Hellwig 已提交
1932 1933 1934 1935
	memset(&scm, 0, sizeof(scm));

	scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
	unix_set_secdata(&scm, skb);
L
Linus Torvalds 已提交
1936

E
Eric Dumazet 已提交
1937
	if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
1938
		if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
1939
			unix_detach_fds(&scm, skb);
1940 1941

		sk_peek_offset_bwd(sk, skb->len);
E
Eric Dumazet 已提交
1942
	} else {
L
Linus Torvalds 已提交
1943 1944 1945 1946 1947 1948
		/* It is questionable: on PEEK we could:
		   - do not return fds - good, but too simple 8)
		   - return fds, and do not return them on read (old strategy,
		     apparently wrong)
		   - clone fds (I chose it for now, it is the most universal
		     solution)
1949 1950 1951 1952 1953

		   POSIX 1003.1g does not actually define this clearly
		   at all. POSIX 1003.1g doesn't define a lot of things
		   clearly however!

L
Linus Torvalds 已提交
1954
		*/
1955 1956 1957

		sk_peek_offset_fwd(sk, size);

L
Linus Torvalds 已提交
1958
		if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
1959
			scm.fp = scm_fp_dup(UNIXCB(skb).fp);
L
Linus Torvalds 已提交
1960
	}
1961
	err = (flags & MSG_TRUNC) ? skb->len - skip : size;
L
Linus Torvalds 已提交
1962

C
Christoph Hellwig 已提交
1963
	scm_recv(sock, msg, &scm, flags);
L
Linus Torvalds 已提交
1964 1965

out_free:
E
Eric Dumazet 已提交
1966
	skb_free_datagram(sk, skb);
L
Linus Torvalds 已提交
1967
out_unlock:
I
Ingo Molnar 已提交
1968
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
1969 1970 1971 1972 1973
out:
	return err;
}

/*
1974
 *	Sleep until more data has arrived. But check for races..
L
Linus Torvalds 已提交
1975
 */
1976
static long unix_stream_data_wait(struct sock *sk, long timeo,
1977
				  struct sk_buff *last, unsigned int last_len)
L
Linus Torvalds 已提交
1978
{
1979
	struct sk_buff *tail;
L
Linus Torvalds 已提交
1980 1981
	DEFINE_WAIT(wait);

1982
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1983 1984

	for (;;) {
E
Eric Dumazet 已提交
1985
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
L
Linus Torvalds 已提交
1986

1987 1988 1989
		tail = skb_peek_tail(&sk->sk_receive_queue);
		if (tail != last ||
		    (tail && tail->len != last_len) ||
L
Linus Torvalds 已提交
1990 1991 1992 1993 1994 1995 1996
		    sk->sk_err ||
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
		    signal_pending(current) ||
		    !timeo)
			break;

		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1997
		unix_state_unlock(sk);
1998
		timeo = freezable_schedule_timeout(timeo);
1999
		unix_state_lock(sk);
2000 2001 2002 2003

		if (sock_flag(sk, SOCK_DEAD))
			break;

L
Linus Torvalds 已提交
2004 2005 2006
		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
	}

E
Eric Dumazet 已提交
2007
	finish_wait(sk_sleep(sk), &wait);
2008
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
2009 2010 2011
	return timeo;
}

2012 2013 2014 2015 2016
static unsigned int unix_skb_len(const struct sk_buff *skb)
{
	return skb->len - UNIXCB(skb).consumed;
}

2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028
struct unix_stream_read_state {
	int (*recv_actor)(struct sk_buff *, int, int,
			  struct unix_stream_read_state *);
	struct socket *socket;
	struct msghdr *msg;
	struct pipe_inode_info *pipe;
	size_t size;
	int flags;
	unsigned int splice_flags;
};

static int unix_stream_read_generic(struct unix_stream_read_state *state)
L
Linus Torvalds 已提交
2029
{
C
Christoph Hellwig 已提交
2030
	struct scm_cookie scm;
2031
	struct socket *sock = state->socket;
L
Linus Torvalds 已提交
2032 2033 2034
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
	int copied = 0;
2035
	int flags = state->flags;
2036
	int noblock = flags & MSG_DONTWAIT;
2037
	bool check_creds = false;
L
Linus Torvalds 已提交
2038 2039 2040
	int target;
	int err = 0;
	long timeo;
2041
	int skip;
2042 2043
	size_t size = state->size;
	unsigned int last_len;
L
Linus Torvalds 已提交
2044 2045 2046 2047 2048 2049

	err = -EINVAL;
	if (sk->sk_state != TCP_ESTABLISHED)
		goto out;

	err = -EOPNOTSUPP;
2050
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
2051 2052
		goto out;

2053
	target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2054
	timeo = sock_rcvtimeo(sk, noblock);
L
Linus Torvalds 已提交
2055

2056 2057
	memset(&scm, 0, sizeof(scm));

L
Linus Torvalds 已提交
2058 2059 2060
	/* Lock the socket to prevent queue disordering
	 * while sleeps in memcpy_tomsg
	 */
2061
	err = mutex_lock_interruptible(&u->readlock);
2062 2063 2064 2065 2066
	if (unlikely(err)) {
		/* recvmsg() in non blocking mode is supposed to return -EAGAIN
		 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
		 */
		err = noblock ? -EAGAIN : -ERESTARTSYS;
2067 2068
		goto out;
	}
L
Linus Torvalds 已提交
2069

2070 2071 2072 2073 2074
	if (flags & MSG_PEEK)
		skip = sk_peek_offset(sk, flags);
	else
		skip = 0;

E
Eric Dumazet 已提交
2075
	do {
L
Linus Torvalds 已提交
2076
		int chunk;
2077
		bool drop_skb;
2078
		struct sk_buff *skb, *last;
L
Linus Torvalds 已提交
2079

2080
		unix_state_lock(sk);
2081 2082 2083 2084
		if (sock_flag(sk, SOCK_DEAD)) {
			err = -ECONNRESET;
			goto unlock;
		}
2085
		last = skb = skb_peek(&sk->sk_receive_queue);
2086
		last_len = last ? last->len : 0;
2087
again:
E
Eric Dumazet 已提交
2088
		if (skb == NULL) {
E
Eric Dumazet 已提交
2089
			unix_sk(sk)->recursion_level = 0;
L
Linus Torvalds 已提交
2090
			if (copied >= target)
2091
				goto unlock;
L
Linus Torvalds 已提交
2092 2093 2094 2095

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
2096

E
Eric Dumazet 已提交
2097 2098
			err = sock_error(sk);
			if (err)
2099
				goto unlock;
L
Linus Torvalds 已提交
2100
			if (sk->sk_shutdown & RCV_SHUTDOWN)
2101 2102 2103
				goto unlock;

			unix_state_unlock(sk);
L
Linus Torvalds 已提交
2104 2105 2106
			err = -EAGAIN;
			if (!timeo)
				break;
I
Ingo Molnar 已提交
2107
			mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
2108

2109 2110
			timeo = unix_stream_data_wait(sk, timeo, last,
						      last_len);
L
Linus Torvalds 已提交
2111

2112 2113
			if (signal_pending(current) ||
			    mutex_lock_interruptible(&u->readlock)) {
L
Linus Torvalds 已提交
2114 2115 2116
				err = sock_intr_errno(timeo);
				goto out;
			}
2117

L
Linus Torvalds 已提交
2118
			continue;
2119
unlock:
2120 2121
			unix_state_unlock(sk);
			break;
L
Linus Torvalds 已提交
2122
		}
2123

2124 2125
		while (skip >= unix_skb_len(skb)) {
			skip -= unix_skb_len(skb);
2126
			last = skb;
2127
			last_len = skb->len;
2128
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
2129 2130
			if (!skb)
				goto again;
2131 2132
		}

2133
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
2134 2135 2136

		if (check_creds) {
			/* Never glue messages from different writers */
C
Christoph Hellwig 已提交
2137 2138
			if ((UNIXCB(skb).pid  != scm.pid) ||
			    !uid_eq(UNIXCB(skb).uid, scm.creds.uid) ||
2139 2140
			    !gid_eq(UNIXCB(skb).gid, scm.creds.gid) ||
			    !unix_secdata_eq(&scm, skb))
L
Linus Torvalds 已提交
2141
				break;
2142
		} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
L
Linus Torvalds 已提交
2143
			/* Copy credentials */
C
Christoph Hellwig 已提交
2144
			scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2145
			unix_set_secdata(&scm, skb);
2146
			check_creds = true;
L
Linus Torvalds 已提交
2147 2148 2149
		}

		/* Copy address just once */
2150 2151 2152 2153
		if (state->msg && state->msg->msg_name) {
			DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
					 state->msg->msg_name);
			unix_copy_addr(state->msg, skb->sk);
L
Linus Torvalds 已提交
2154 2155 2156
			sunaddr = NULL;
		}

2157
		chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2158
		skb_get(skb);
2159
		chunk = state->recv_actor(skb, skip, chunk, state);
2160 2161 2162
		drop_skb = !unix_skb_len(skb);
		/* skb is only safe to use if !drop_skb */
		consume_skb(skb);
2163
		if (chunk < 0) {
L
Linus Torvalds 已提交
2164 2165 2166 2167 2168 2169 2170
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182
		if (drop_skb) {
			/* the skb was touched by a concurrent reader;
			 * we should not expect anything from this skb
			 * anymore and assume it invalid - we can be
			 * sure it was dropped from the socket queue
			 *
			 * let's report a short read
			 */
			err = 0;
			break;
		}

L
Linus Torvalds 已提交
2183
		/* Mark read part of skb as used */
E
Eric Dumazet 已提交
2184
		if (!(flags & MSG_PEEK)) {
2185
			UNIXCB(skb).consumed += chunk;
L
Linus Torvalds 已提交
2186

2187 2188
			sk_peek_offset_bwd(sk, chunk);

L
Linus Torvalds 已提交
2189
			if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2190
				unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
2191

2192
			if (unix_skb_len(skb))
L
Linus Torvalds 已提交
2193 2194
				break;

2195
			skb_unlink(skb, &sk->sk_receive_queue);
2196
			consume_skb(skb);
L
Linus Torvalds 已提交
2197

C
Christoph Hellwig 已提交
2198
			if (scm.fp)
L
Linus Torvalds 已提交
2199
				break;
E
Eric Dumazet 已提交
2200
		} else {
L
Linus Torvalds 已提交
2201 2202 2203
			/* It is questionable, see note in unix_dgram_recvmsg.
			 */
			if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2204
				scm.fp = scm_fp_dup(UNIXCB(skb).fp);
L
Linus Torvalds 已提交
2205

2206
			sk_peek_offset_fwd(sk, chunk);
2207

2208 2209 2210
			if (UNIXCB(skb).fp)
				break;

2211
			skip = 0;
2212 2213 2214 2215 2216 2217 2218
			last = skb;
			last_len = skb->len;
			unix_state_lock(sk);
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
			if (skb)
				goto again;
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
2219 2220 2221 2222
			break;
		}
	} while (size);

I
Ingo Molnar 已提交
2223
	mutex_unlock(&u->readlock);
2224 2225 2226 2227
	if (state->msg)
		scm_recv(sock, state->msg, &scm, flags);
	else
		scm_destroy(&scm);
L
Linus Torvalds 已提交
2228 2229 2230 2231
out:
	return copied ? : err;
}

2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302
static int unix_stream_read_actor(struct sk_buff *skb,
				  int skip, int chunk,
				  struct unix_stream_read_state *state)
{
	int ret;

	ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
				    state->msg, chunk);
	return ret ?: chunk;
}

static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
			       size_t size, int flags)
{
	struct unix_stream_read_state state = {
		.recv_actor = unix_stream_read_actor,
		.socket = sock,
		.msg = msg,
		.size = size,
		.flags = flags
	};

	return unix_stream_read_generic(&state);
}

static ssize_t skb_unix_socket_splice(struct sock *sk,
				      struct pipe_inode_info *pipe,
				      struct splice_pipe_desc *spd)
{
	int ret;
	struct unix_sock *u = unix_sk(sk);

	mutex_unlock(&u->readlock);
	ret = splice_to_pipe(pipe, spd);
	mutex_lock(&u->readlock);

	return ret;
}

static int unix_stream_splice_actor(struct sk_buff *skb,
				    int skip, int chunk,
				    struct unix_stream_read_state *state)
{
	return skb_splice_bits(skb, state->socket->sk,
			       UNIXCB(skb).consumed + skip,
			       state->pipe, chunk, state->splice_flags,
			       skb_unix_socket_splice);
}

static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,
				       struct pipe_inode_info *pipe,
				       size_t size, unsigned int flags)
{
	struct unix_stream_read_state state = {
		.recv_actor = unix_stream_splice_actor,
		.socket = sock,
		.pipe = pipe,
		.size = size,
		.splice_flags = flags,
	};

	if (unlikely(*ppos))
		return -ESPIPE;

	if (sock->file->f_flags & O_NONBLOCK ||
	    flags & SPLICE_F_NONBLOCK)
		state.flags = MSG_DONTWAIT;

	return unix_stream_read_generic(&state);
}

L
Linus Torvalds 已提交
2303 2304 2305 2306 2307
static int unix_shutdown(struct socket *sock, int mode)
{
	struct sock *sk = sock->sk;
	struct sock *other;

2308 2309 2310 2311 2312 2313 2314 2315
	if (mode < SHUT_RD || mode > SHUT_RDWR)
		return -EINVAL;
	/* This maps:
	 * SHUT_RD   (0) -> RCV_SHUTDOWN  (1)
	 * SHUT_WR   (1) -> SEND_SHUTDOWN (2)
	 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
	 */
	++mode;
2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341

	unix_state_lock(sk);
	sk->sk_shutdown |= mode;
	other = unix_peer(sk);
	if (other)
		sock_hold(other);
	unix_state_unlock(sk);
	sk->sk_state_change(sk);

	if (other &&
		(sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {

		int peer_mode = 0;

		if (mode&RCV_SHUTDOWN)
			peer_mode |= SEND_SHUTDOWN;
		if (mode&SEND_SHUTDOWN)
			peer_mode |= RCV_SHUTDOWN;
		unix_state_lock(other);
		other->sk_shutdown |= peer_mode;
		unix_state_unlock(other);
		other->sk_state_change(other);
		if (peer_mode == SHUTDOWN_MASK)
			sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
		else if (peer_mode & RCV_SHUTDOWN)
			sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
L
Linus Torvalds 已提交
2342
	}
2343 2344 2345
	if (other)
		sock_put(other);

L
Linus Torvalds 已提交
2346 2347 2348
	return 0;
}

2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360
long unix_inq_len(struct sock *sk)
{
	struct sk_buff *skb;
	long amount = 0;

	if (sk->sk_state == TCP_LISTEN)
		return -EINVAL;

	spin_lock(&sk->sk_receive_queue.lock);
	if (sk->sk_type == SOCK_STREAM ||
	    sk->sk_type == SOCK_SEQPACKET) {
		skb_queue_walk(&sk->sk_receive_queue, skb)
2361
			amount += unix_skb_len(skb);
2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378
	} else {
		skb = skb_peek(&sk->sk_receive_queue);
		if (skb)
			amount = skb->len;
	}
	spin_unlock(&sk->sk_receive_queue.lock);

	return amount;
}
EXPORT_SYMBOL_GPL(unix_inq_len);

long unix_outq_len(struct sock *sk)
{
	return sk_wmem_alloc_get(sk);
}
EXPORT_SYMBOL_GPL(unix_outq_len);

L
Linus Torvalds 已提交
2379 2380 2381
static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;
2382
	long amount = 0;
L
Linus Torvalds 已提交
2383 2384
	int err;

E
Eric Dumazet 已提交
2385 2386
	switch (cmd) {
	case SIOCOUTQ:
2387
		amount = unix_outq_len(sk);
E
Eric Dumazet 已提交
2388 2389 2390
		err = put_user(amount, (int __user *)arg);
		break;
	case SIOCINQ:
2391 2392 2393 2394
		amount = unix_inq_len(sk);
		if (amount < 0)
			err = amount;
		else
L
Linus Torvalds 已提交
2395
			err = put_user(amount, (int __user *)arg);
2396
		break;
E
Eric Dumazet 已提交
2397 2398 2399
	default:
		err = -ENOIOCTLCMD;
		break;
L
Linus Torvalds 已提交
2400 2401 2402 2403
	}
	return err;
}

E
Eric Dumazet 已提交
2404
static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
L
Linus Torvalds 已提交
2405 2406 2407 2408
{
	struct sock *sk = sock->sk;
	unsigned int mask;

E
Eric Dumazet 已提交
2409
	sock_poll_wait(file, sk_sleep(sk), wait);
L
Linus Torvalds 已提交
2410 2411 2412 2413 2414 2415 2416
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err)
		mask |= POLLERR;
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;
2417
	if (sk->sk_shutdown & RCV_SHUTDOWN)
E
Eric Dumazet 已提交
2418
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
L
Linus Torvalds 已提交
2419 2420

	/* readable? */
E
Eric Dumazet 已提交
2421
	if (!skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
2422 2423 2424
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
E
Eric Dumazet 已提交
2425 2426
	if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
	    sk->sk_state == TCP_CLOSE)
L
Linus Torvalds 已提交
2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438
		mask |= POLLHUP;

	/*
	 * we set writable also when the other side has shut down the
	 * connection. This prevents stuck sockets.
	 */
	if (unix_writable(sk))
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;

	return mask;
}

2439 2440
static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
				    poll_table *wait)
2441
{
2442 2443
	struct sock *sk = sock->sk, *other;
	unsigned int mask, writable;
2444

E
Eric Dumazet 已提交
2445
	sock_poll_wait(file, sk_sleep(sk), wait);
2446 2447 2448 2449
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2450
		mask |= POLLERR |
2451
			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2452

2453
	if (sk->sk_shutdown & RCV_SHUTDOWN)
2454
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2455 2456 2457 2458
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
2459
	if (!skb_queue_empty(&sk->sk_receive_queue))
2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
	if (sk->sk_type == SOCK_SEQPACKET) {
		if (sk->sk_state == TCP_CLOSE)
			mask |= POLLHUP;
		/* connection hasn't started yet? */
		if (sk->sk_state == TCP_SYN_SENT)
			return mask;
	}

E
Eric Dumazet 已提交
2471
	/* No write status requested, avoid expensive OUT tests. */
2472
	if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
E
Eric Dumazet 已提交
2473 2474
		return mask;

2475
	writable = unix_writable(sk);
2476 2477 2478 2479 2480 2481
	other = unix_peer_get(sk);
	if (other) {
		if (unix_peer(other) != sk) {
			sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
			if (unix_recvq_full(other))
				writable = 0;
2482
		}
2483
		sock_put(other);
2484 2485 2486
	}

	if (writable)
2487 2488 2489 2490 2491 2492
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	return mask;
}
L
Linus Torvalds 已提交
2493 2494

#ifdef CONFIG_PROC_FS
2495

E
Eric Dumazet 已提交
2496 2497 2498 2499 2500
#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)

#define get_bucket(x) ((x) >> BUCKET_SPACE)
#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2501

E
Eric Dumazet 已提交
2502
static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
L
Linus Torvalds 已提交
2503
{
E
Eric Dumazet 已提交
2504 2505 2506 2507
	unsigned long offset = get_offset(*pos);
	unsigned long bucket = get_bucket(*pos);
	struct sock *sk;
	unsigned long count = 0;
L
Linus Torvalds 已提交
2508

E
Eric Dumazet 已提交
2509 2510
	for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
		if (sock_net(sk) != seq_file_net(seq))
2511
			continue;
E
Eric Dumazet 已提交
2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530
		if (++count == offset)
			break;
	}

	return sk;
}

static struct sock *unix_next_socket(struct seq_file *seq,
				     struct sock *sk,
				     loff_t *pos)
{
	unsigned long bucket;

	while (sk > (struct sock *)SEQ_START_TOKEN) {
		sk = sk_next(sk);
		if (!sk)
			goto next_bucket;
		if (sock_net(sk) == seq_file_net(seq))
			return sk;
L
Linus Torvalds 已提交
2531
	}
E
Eric Dumazet 已提交
2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542

	do {
		sk = unix_from_bucket(seq, pos);
		if (sk)
			return sk;

next_bucket:
		bucket = get_bucket(*pos) + 1;
		*pos = set_bucket_offset(bucket, 1);
	} while (bucket < ARRAY_SIZE(unix_socket_table));

L
Linus Torvalds 已提交
2543 2544 2545 2546
	return NULL;
}

static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2547
	__acquires(unix_table_lock)
L
Linus Torvalds 已提交
2548
{
2549
	spin_lock(&unix_table_lock);
E
Eric Dumazet 已提交
2550 2551 2552 2553 2554 2555 2556 2557

	if (!*pos)
		return SEQ_START_TOKEN;

	if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
		return NULL;

	return unix_next_socket(seq, NULL, pos);
L
Linus Torvalds 已提交
2558 2559 2560 2561 2562
}

static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;
E
Eric Dumazet 已提交
2563
	return unix_next_socket(seq, v, pos);
L
Linus Torvalds 已提交
2564 2565 2566
}

static void unix_seq_stop(struct seq_file *seq, void *v)
2567
	__releases(unix_table_lock)
L
Linus Torvalds 已提交
2568
{
2569
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
2570 2571 2572 2573
}

static int unix_seq_show(struct seq_file *seq, void *v)
{
2574

J
Joe Perches 已提交
2575
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2576 2577 2578 2579 2580
		seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
			 "Inode Path\n");
	else {
		struct sock *s = v;
		struct unix_sock *u = unix_sk(s);
2581
		unix_state_lock(s);
L
Linus Torvalds 已提交
2582

D
Dan Rosenberg 已提交
2583
		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
L
Linus Torvalds 已提交
2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608
			s,
			atomic_read(&s->sk_refcnt),
			0,
			s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
			s->sk_type,
			s->sk_socket ?
			(s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
			(s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
			sock_i_ino(s));

		if (u->addr) {
			int i, len;
			seq_putc(seq, ' ');

			i = 0;
			len = u->addr->len - sizeof(short);
			if (!UNIX_ABSTRACT(s))
				len--;
			else {
				seq_putc(seq, '@');
				i++;
			}
			for ( ; i < len; i++)
				seq_putc(seq, u->addr->name->sun_path[i]);
		}
2609
		unix_state_unlock(s);
L
Linus Torvalds 已提交
2610 2611 2612 2613 2614 2615
		seq_putc(seq, '\n');
	}

	return 0;
}

2616
static const struct seq_operations unix_seq_ops = {
L
Linus Torvalds 已提交
2617 2618 2619 2620 2621 2622 2623 2624
	.start  = unix_seq_start,
	.next   = unix_seq_next,
	.stop   = unix_seq_stop,
	.show   = unix_seq_show,
};

static int unix_seq_open(struct inode *inode, struct file *file)
{
2625
	return seq_open_net(inode, file, &unix_seq_ops,
E
Eric Dumazet 已提交
2626
			    sizeof(struct seq_net_private));
L
Linus Torvalds 已提交
2627 2628
}

2629
static const struct file_operations unix_seq_fops = {
L
Linus Torvalds 已提交
2630 2631 2632 2633
	.owner		= THIS_MODULE,
	.open		= unix_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2634
	.release	= seq_release_net,
L
Linus Torvalds 已提交
2635 2636 2637 2638
};

#endif

2639
static const struct net_proto_family unix_family_ops = {
L
Linus Torvalds 已提交
2640 2641 2642 2643 2644
	.family = PF_UNIX,
	.create = unix_create,
	.owner	= THIS_MODULE,
};

2645

2646
static int __net_init unix_net_init(struct net *net)
2647 2648 2649
{
	int error = -ENOMEM;

2650
	net->unx.sysctl_max_dgram_qlen = 10;
2651 2652
	if (unix_sysctl_register(net))
		goto out;
2653

2654
#ifdef CONFIG_PROC_FS
2655
	if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2656
		unix_sysctl_unregister(net);
2657
		goto out;
2658
	}
2659 2660 2661
#endif
	error = 0;
out:
2662
	return error;
2663 2664
}

2665
static void __net_exit unix_net_exit(struct net *net)
2666
{
2667
	unix_sysctl_unregister(net);
2668
	remove_proc_entry("unix", net->proc_net);
2669 2670 2671 2672 2673 2674 2675
}

static struct pernet_operations unix_net_ops = {
	.init = unix_net_init,
	.exit = unix_net_exit,
};

L
Linus Torvalds 已提交
2676 2677 2678 2679
static int __init af_unix_init(void)
{
	int rc = -1;

2680
	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
L
Linus Torvalds 已提交
2681 2682

	rc = proto_register(&unix_proto, 1);
2683
	if (rc != 0) {
W
wangweidong 已提交
2684
		pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
L
Linus Torvalds 已提交
2685 2686 2687 2688
		goto out;
	}

	sock_register(&unix_family_ops);
2689
	register_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2690 2691 2692 2693 2694 2695 2696 2697
out:
	return rc;
}

static void __exit af_unix_exit(void)
{
	sock_unregister(PF_UNIX);
	proto_unregister(&unix_proto);
2698
	unregister_pernet_subsys(&unix_net_ops);
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}

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/* Earlier than device_initcall() so that other drivers invoking
   request_module() don't end up in a loop when modprobe tries
   to use a UNIX socket. But later than subsys_initcall() because
   we depend on stuff initialised there */
fs_initcall(af_unix_init);
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module_exit(af_unix_exit);

MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_UNIX);