af_unix.c 55.6 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.
 */

#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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struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
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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#define unix_sockets_unbound	(&unix_socket_table[UNIX_HASH_SIZE])

#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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	memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
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}

static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
{
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	scm->secid = *UNIXSID(skb);
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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)
{ }
#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 unix_hash_fold(__wsum n)
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{
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	unsigned hash = (__force unsigned)n;
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	hash ^= hash>>16;
	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 *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 hash)
{
	struct sock *s;
	struct hlist_node *node;

	sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
		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,
						   unsigned hash)
{
	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;
	struct hlist_node *node;

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	spin_lock(&unix_table_lock);
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	sk_for_each(s, node,
		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
		struct dentry *dentry = unix_sk(s)->dentry;

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		if (dentry && dentry->d_inode == 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;
}

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

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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		printk(KERN_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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	printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
		atomic_long_read(&unix_nr_socks));
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#endif
}

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static int unix_release_sock(struct sock *sk, int embrion)
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{
	struct unix_sock *u = unix_sk(sk);
	struct dentry *dentry;
	struct vfsmount *mnt;
	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;
	dentry	     = u->dentry;
	u->dentry    = NULL;
	mnt	     = u->mnt;
	u->mnt	     = NULL;
	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	      */
		kfree_skb(skb);
	}

	if (dentry) {
		dput(dentry);
		mntput(mnt);
	}

	sock_put(sk);

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

	/*
	 * Fixme: BSD difference: In BSD all sockets connected to use get
	 *	  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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	return 0;
}

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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;
	const struct cred *old_cred = 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);
	if (old_cred)
		put_cred(old_cred);
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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);
static int unix_stream_sendmsg(struct kiocb *, struct socket *,
			       struct msghdr *, size_t);
static int unix_stream_recvmsg(struct kiocb *, struct socket *,
			       struct msghdr *, size_t, int);
static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
			      struct msghdr *, size_t);
static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
			      struct msghdr *, size_t, int);
static int unix_dgram_connect(struct socket *, struct sockaddr *,
			      int, int);
static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
				  struct msghdr *, size_t);
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static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
				  struct msghdr *, size_t, int);
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static void unix_set_peek_off(struct sock *sk, int val)
{
	struct unix_sock *u = unix_sk(sk);

	mutex_lock(&u->readlock);
	sk->sk_peek_off = val;
	mutex_unlock(&u->readlock);
}


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static const struct proto_ops unix_stream_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,
	.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,
	.sendpage =	sock_no_sendpage,
};

564
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,
573
	.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,
583
	.set_peek_off =	unix_set_peek_off,
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};

586
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,
595
	.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,
602
	.recvmsg =	unix_seqpacket_recvmsg,
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	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
605
	.set_peek_off =	unix_set_peek_off,
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};

static struct proto unix_proto = {
609 610 611
	.name			= "UNIX",
	.owner			= THIS_MODULE,
	.obj_size		= sizeof(struct unix_sock),
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};

614 615 616 617 618 619 620 621
/*
 * 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;

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

E
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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;

631
	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
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	if (!sk)
		goto out;

E
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635
	sock_init_data(sock, sk);
636 637
	lockdep_set_class(&sk->sk_receive_queue.lock,
				&af_unix_sk_receive_queue_lock_key);
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	sk->sk_write_space	= unix_write_space;
640
	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);
	u->dentry = NULL;
	u->mnt	  = NULL;
645
	spin_lock_init(&u->lock);
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	atomic_long_set(&u->inflight, 0);
647
	INIT_LIST_HEAD(&u->link);
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648
	mutex_init(&u->readlock); /* single task reading lock */
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	init_waitqueue_head(&u->peer_wait);
	unix_insert_socket(unix_sockets_unbound, sk);
out:
652
	if (sk == NULL)
E
Eric Dumazet 已提交
653
		atomic_long_dec(&unix_nr_socks);
654 655
	else {
		local_bh_disable();
656
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
657 658
		local_bh_enable();
	}
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	return sk;
}

662 663
static int unix_create(struct net *net, struct socket *sock, int protocol,
		       int kern)
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{
	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:
679
		sock->type = SOCK_DGRAM;
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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;
	}

690
	return unix_create1(net, sock) ? 0 : -ENOMEM;
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}

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

	if (!sk)
		return 0;

	sock->sk = NULL;

E
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	return unix_release_sock(sk, 0);
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}

static int unix_autobind(struct socket *sock)
{
	struct sock *sk = sock->sk;
708
	struct net *net = sock_net(sk);
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	struct unix_sock *u = unix_sk(sk);
	static u32 ordernum = 1;
E
Eric Dumazet 已提交
711
	struct unix_address *addr;
L
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712
	int err;
713
	unsigned int retries = 0;
L
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714

I
Ingo Molnar 已提交
715
	mutex_lock(&u->readlock);
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716 717 718 719 720 721

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

	err = -ENOMEM;
722
	addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
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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);
731
	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
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733
	spin_lock(&unix_table_lock);
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	ordernum = (ordernum+1)&0xFFFFF;

736
	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
L
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				      addr->hash)) {
738
		spin_unlock(&unix_table_lock);
739 740 741 742 743 744 745 746 747 748 749
		/*
		 * __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);
757
	spin_unlock(&unix_table_lock);
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	err = 0;

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out:	mutex_unlock(&u->readlock);
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	return err;
}

764 765
static struct sock *unix_find_other(struct net *net,
				    struct sockaddr_un *sunname, int len,
L
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				    int type, unsigned hash, int *error)
{
	struct sock *u;
769
	struct path path;
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770
	int err = 0;
771

L
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	if (sunname->sun_path[0]) {
773 774
		struct inode *inode;
		err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
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		if (err)
			goto fail;
777 778
		inode = path.dentry->d_inode;
		err = inode_permission(inode, MAY_WRITE);
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		if (err)
			goto put_fail;

		err = -ECONNREFUSED;
783
		if (!S_ISSOCK(inode->i_mode))
L
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			goto put_fail;
785
		u = unix_find_socket_byinode(inode);
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		if (!u)
			goto put_fail;

		if (u->sk_type == type)
790
			touch_atime(path.mnt, path.dentry);
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792
		path_put(&path);
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793

794
		err = -EPROTOTYPE;
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		if (u->sk_type != type) {
			sock_put(u);
			goto fail;
		}
	} else {
		err = -ECONNREFUSED;
801
		u = unix_find_socket_byname(net, sunname, len, type, hash);
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		if (u) {
			struct dentry *dentry;
			dentry = unix_sk(u)->dentry;
			if (dentry)
				touch_atime(unix_sk(u)->mnt, dentry);
		} else
			goto fail;
	}
	return u;

put_fail:
813
	path_put(&path);
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fail:
815
	*error = err;
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	return NULL;
}


static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sock *sk = sock->sk;
823
	struct net *net = sock_net(sk);
L
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	struct unix_sock *u = unix_sk(sk);
825
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
826
	char *sun_path = sunaddr->sun_path;
E
Eric Dumazet 已提交
827
	struct dentry *dentry = NULL;
828
	struct path path;
L
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	int err;
	unsigned hash;
	struct unix_address *addr;
	struct hlist_head *list;

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

838
	if (addr_len == sizeof(short)) {
L
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		err = unix_autobind(sock);
		goto out;
	}

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

I
Ingo Molnar 已提交
848
	mutex_lock(&u->readlock);
L
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849 850 851 852 853 854 855 856 857 858 859 860 861 862 863

	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);

864
	if (sun_path[0]) {
A
Al Viro 已提交
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		umode_t mode;
L
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866 867 868 869 870
		err = 0;
		/*
		 * Get the parent directory, calculate the hash for last
		 * component.
		 */
871
		dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
L
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872 873
		err = PTR_ERR(dentry);
		if (IS_ERR(dentry))
874
			goto out_mknod_parent;
875

L
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876 877 878 879
		/*
		 * All right, let's create it.
		 */
		mode = S_IFSOCK |
A
Al Viro 已提交
880
		       (SOCK_INODE(sock)->i_mode & ~current_umask());
881
		err = mnt_want_write(path.mnt);
882 883
		if (err)
			goto out_mknod_dput;
884
		err = security_path_mknod(&path, dentry, mode, 0);
885 886
		if (err)
			goto out_mknod_drop_write;
887
		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
888
out_mknod_drop_write:
889
		mnt_drop_write(path.mnt);
L
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890 891
		if (err)
			goto out_mknod_dput;
892 893 894
		mutex_unlock(&path.dentry->d_inode->i_mutex);
		dput(path.dentry);
		path.dentry = dentry;
L
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895 896 897 898

		addr->hash = UNIX_HASH_SIZE;
	}

899
	spin_lock(&unix_table_lock);
L
Linus Torvalds 已提交
900

901
	if (!sun_path[0]) {
L
Linus Torvalds 已提交
902
		err = -EADDRINUSE;
903
		if (__unix_find_socket_byname(net, sunaddr, addr_len,
L
Linus Torvalds 已提交
904 905 906 907 908 909 910 911
					      sk->sk_type, hash)) {
			unix_release_addr(addr);
			goto out_unlock;
		}

		list = &unix_socket_table[addr->hash];
	} else {
		list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
912 913
		u->dentry = path.dentry;
		u->mnt    = path.mnt;
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914 915 916 917 918 919 920 921
	}

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

out_unlock:
922
	spin_unlock(&unix_table_lock);
L
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923
out_up:
I
Ingo Molnar 已提交
924
	mutex_unlock(&u->readlock);
L
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925 926 927 928 929
out:
	return err;

out_mknod_dput:
	dput(dentry);
930 931
	mutex_unlock(&path.dentry->d_inode->i_mutex);
	path_put(&path);
L
Linus Torvalds 已提交
932
out_mknod_parent:
933 934
	if (err == -EEXIST)
		err = -EADDRINUSE;
L
Linus Torvalds 已提交
935 936 937 938
	unix_release_addr(addr);
	goto out_up;
}

939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963
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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964 965 966 967
static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
			      int alen, int flags)
{
	struct sock *sk = sock->sk;
968
	struct net *net = sock_net(sk);
969
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
L
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970 971 972 973 974 975 976 977 978 979 980 981 982 983
	struct sock *other;
	unsigned hash;
	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;

984
restart:
985
		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
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986 987 988
		if (!other)
			goto out;

989 990 991 992 993 994 995 996
		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;
		}
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997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010

		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;
1011
		unix_state_double_lock(sk, other);
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1012 1013 1014 1015 1016 1017 1018
	}

	/*
	 * If it was connected, reconnect.
	 */
	if (unix_peer(sk)) {
		struct sock *old_peer = unix_peer(sk);
1019
		unix_peer(sk) = other;
1020
		unix_state_double_unlock(sk, other);
L
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1021 1022 1023 1024 1025

		if (other != old_peer)
			unix_dgram_disconnected(sk, old_peer);
		sock_put(old_peer);
	} else {
1026
		unix_peer(sk) = other;
1027
		unix_state_double_unlock(sk, other);
L
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1028
	}
1029
	return 0;
L
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1030 1031

out_unlock:
1032
	unix_state_double_unlock(sk, other);
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1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047
	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) &&
1048
		unix_recvq_full(other);
L
Linus Torvalds 已提交
1049

1050
	unix_state_unlock(other);
L
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1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061

	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)
{
1062
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
L
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1063
	struct sock *sk = sock->sk;
1064
	struct net *net = sock_net(sk);
L
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1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078
	struct unix_sock *u = unix_sk(sk), *newu, *otheru;
	struct sock *newsk = NULL;
	struct sock *other = NULL;
	struct sk_buff *skb = NULL;
	unsigned hash;
	int st;
	int err;
	long timeo;

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

1079 1080
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
	    (err = unix_autobind(sock)) != 0)
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1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092
		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 */
1093
	newsk = unix_create1(sock_net(sk), NULL);
L
Linus Torvalds 已提交
1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
	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. */
1104
	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
L
Linus Torvalds 已提交
1105 1106 1107 1108
	if (!other)
		goto out;

	/* Latch state of peer */
1109
	unix_state_lock(other);
L
Linus Torvalds 已提交
1110 1111 1112

	/* Apparently VFS overslept socket death. Retry. */
	if (sock_flag(other, SOCK_DEAD)) {
1113
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1114 1115 1116 1117 1118 1119 1120
		sock_put(other);
		goto restart;
	}

	err = -ECONNREFUSED;
	if (other->sk_state != TCP_LISTEN)
		goto out_unlock;
1121 1122
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;
L
Linus Torvalds 已提交
1123

1124
	if (unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135
		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;
1136
	}
L
Linus Torvalds 已提交
1137 1138 1139

	/* Latch our state.

D
Daniel Baluta 已提交
1140
	   It is tricky place. We need to grab our state lock and cannot
L
Linus Torvalds 已提交
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163
	   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;
	}

1164
	unix_state_lock_nested(sk);
L
Linus Torvalds 已提交
1165 1166

	if (sk->sk_state != st) {
1167 1168
		unix_state_unlock(sk);
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1169 1170 1171 1172
		sock_put(other);
		goto restart;
	}

1173
	err = security_unix_stream_connect(sk, other, newsk);
L
Linus Torvalds 已提交
1174
	if (err) {
1175
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1176 1177 1178 1179 1180 1181 1182 1183 1184
		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;
1185
	init_peercred(newsk);
L
Linus Torvalds 已提交
1186
	newu = unix_sk(newsk);
1187
	RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
L
Linus Torvalds 已提交
1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
	otheru = unix_sk(other);

	/* copy address information from listening to new sock*/
	if (otheru->addr) {
		atomic_inc(&otheru->addr->refcnt);
		newu->addr = otheru->addr;
	}
	if (otheru->dentry) {
		newu->dentry	= dget(otheru->dentry);
		newu->mnt	= mntget(otheru->mnt);
	}

	/* Set credentials */
1201
	copy_peercred(sk, other);
L
Linus Torvalds 已提交
1202 1203 1204

	sock->state	= SS_CONNECTED;
	sk->sk_state	= TCP_ESTABLISHED;
1205 1206 1207 1208
	sock_hold(newsk);

	smp_mb__after_atomic_inc();	/* sock_hold() does an atomic_inc() */
	unix_peer(sk)	= newsk;
L
Linus Torvalds 已提交
1209

1210
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1211 1212 1213 1214 1215

	/* 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);
1216
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1217 1218 1219 1220 1221 1222
	other->sk_data_ready(other, 0);
	sock_put(other);
	return 0;

out_unlock:
	if (other)
1223
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1224 1225

out:
1226
	kfree_skb(skb);
L
Linus Torvalds 已提交
1227 1228 1229 1230 1231 1232 1233 1234 1235
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
1236
	struct sock *ska = socka->sk, *skb = sockb->sk;
L
Linus Torvalds 已提交
1237 1238 1239 1240

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
1241 1242
	unix_peer(ska) = skb;
	unix_peer(skb) = ska;
1243 1244
	init_peercred(ska);
	init_peercred(skb);
L
Linus Torvalds 已提交
1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262

	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;
}

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
1263
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
L
Linus Torvalds 已提交
1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286
		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 */
1287
	unix_state_lock(tsk);
L
Linus Torvalds 已提交
1288 1289
	newsock->state = SS_CONNECTED;
	sock_graft(tsk, newsock);
1290
	unix_state_unlock(tsk);
L
Linus Torvalds 已提交
1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301
	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;
1302
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
L
Linus Torvalds 已提交
1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316
	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);
1317
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1318 1319 1320 1321 1322 1323 1324 1325 1326 1327
	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);
	}
1328
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340
	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
1341
	for (i = scm->fp->count-1; i >= 0; i--)
L
Linus Torvalds 已提交
1342 1343 1344
		unix_notinflight(scm->fp->fp[i]);
}

1345
static void unix_destruct_scm(struct sk_buff *skb)
L
Linus Torvalds 已提交
1346 1347 1348
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
1349 1350 1351 1352
	scm.pid  = UNIXCB(skb).pid;
	scm.cred = UNIXCB(skb).cred;
	if (UNIXCB(skb).fp)
		unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
1353 1354 1355 1356 1357 1358 1359

	/* 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
1360 1361
#define MAX_RECURSION_LEVEL 4

1362
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
L
Linus Torvalds 已提交
1363 1364
{
	int i;
E
Eric Dumazet 已提交
1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378
	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;
1379 1380 1381 1382 1383 1384 1385 1386 1387 1388

	/*
	 * 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
1389 1390 1391 1392 1393
	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
1394 1395
}

1396
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1397 1398
{
	int err = 0;
1399

1400
	UNIXCB(skb).pid  = get_pid(scm->pid);
1401 1402
	if (scm->cred)
		UNIXCB(skb).cred = get_cred(scm->cred);
1403 1404 1405 1406 1407 1408 1409 1410
	UNIXCB(skb).fp = NULL;
	if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

	skb->destructor = unix_destruct_scm;
	return err;
}

1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428
/*
 * 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)
{
	if (UNIXCB(skb).cred)
		return;
	if (test_bit(SOCK_PASSCRED, &sock->flags) ||
	    !other->sk_socket ||
	    test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
		UNIXCB(skb).pid  = get_pid(task_tgid(current));
		UNIXCB(skb).cred = get_current_cred();
	}
}

L
Linus Torvalds 已提交
1429 1430 1431 1432 1433 1434 1435 1436 1437
/*
 *	Send AF_UNIX data.
 */

static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
			      struct msghdr *msg, size_t len)
{
	struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
	struct sock *sk = sock->sk;
1438
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1439
	struct unix_sock *u = unix_sk(sk);
1440
	struct sockaddr_un *sunaddr = msg->msg_name;
L
Linus Torvalds 已提交
1441 1442 1443 1444
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
	unsigned hash;
1445
	struct sk_buff *skb;
L
Linus Torvalds 已提交
1446 1447
	long timeo;
	struct scm_cookie tmp_scm;
E
Eric Dumazet 已提交
1448
	int max_level;
L
Linus Torvalds 已提交
1449 1450 1451

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1452
	wait_for_unix_gc();
L
Linus Torvalds 已提交
1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473
	err = scm_send(sock, msg, siocb->scm);
	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;
	}

1474 1475
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
	    && (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1476 1477 1478 1479 1480 1481 1482
		goto out;

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

	skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1483
	if (skb == NULL)
L
Linus Torvalds 已提交
1484 1485
		goto out;

1486
	err = unix_scm_to_skb(siocb->scm, skb, true);
E
Eric Dumazet 已提交
1487
	if (err < 0)
1488
		goto out_free;
E
Eric Dumazet 已提交
1489
	max_level = err + 1;
1490
	unix_get_secdata(siocb->scm, skb);
C
Catherine Zhang 已提交
1491

1492
	skb_reset_transport_header(skb);
E
Eric Dumazet 已提交
1493
	err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
L
Linus Torvalds 已提交
1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504
	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;

1505
		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
L
Linus Torvalds 已提交
1506
					hash, &err);
1507
		if (other == NULL)
L
Linus Torvalds 已提交
1508 1509 1510
			goto out_free;
	}

A
Alban Crequy 已提交
1511 1512 1513 1514 1515 1516
	if (sk_filter(other, skb) < 0) {
		/* Toss the packet but do not return any error to the sender */
		err = len;
		goto out_free;
	}

1517
	unix_state_lock(other);
L
Linus Torvalds 已提交
1518 1519 1520 1521 1522 1523 1524 1525 1526
	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
		 */
1527
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1528 1529 1530
		sock_put(other);

		err = 0;
1531
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1532
		if (unix_peer(sk) == other) {
1533
			unix_peer(sk) = NULL;
1534
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1535 1536 1537 1538 1539

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
1540
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558
		}

		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;
	}

1559
	if (unix_peer(other) != sk && unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573
		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;
	}

1574 1575
	if (sock_flag(other, SOCK_RCVTSTAMP))
		__net_timestamp(skb);
1576
	maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1577
	skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1578 1579
	if (max_level > unix_sk(other)->recursion_level)
		unix_sk(other)->recursion_level = max_level;
1580
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1581 1582
	other->sk_data_ready(other, len);
	sock_put(other);
1583
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1584 1585 1586
	return len;

out_unlock:
1587
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1588 1589 1590 1591 1592
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
1593
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1594 1595 1596
	return err;
}

1597

L
Linus Torvalds 已提交
1598 1599 1600 1601 1602 1603
static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
			       struct msghdr *msg, size_t len)
{
	struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
	struct sock *sk = sock->sk;
	struct sock *other = NULL;
E
Eric Dumazet 已提交
1604
	int err, size;
1605
	struct sk_buff *skb;
1606
	int sent = 0;
L
Linus Torvalds 已提交
1607
	struct scm_cookie tmp_scm;
1608
	bool fds_sent = false;
E
Eric Dumazet 已提交
1609
	int max_level;
L
Linus Torvalds 已提交
1610 1611 1612

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1613
	wait_for_unix_gc();
L
Linus Torvalds 已提交
1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626
	err = scm_send(sock, msg, siocb->scm);
	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;
1627
		other = unix_peer(sk);
L
Linus Torvalds 已提交
1628 1629 1630 1631 1632 1633 1634
		if (!other)
			goto out_err;
	}

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

E
Eric Dumazet 已提交
1635
	while (sent < len) {
L
Linus Torvalds 已提交
1636
		/*
1637 1638
		 *	Optimisation for the fact that under 0.01% of X
		 *	messages typically need breaking up.
L
Linus Torvalds 已提交
1639 1640
		 */

1641
		size = len-sent;
L
Linus Torvalds 已提交
1642 1643

		/* Keep two messages in the pipe so it schedules better */
1644 1645
		if (size > ((sk->sk_sndbuf >> 1) - 64))
			size = (sk->sk_sndbuf >> 1) - 64;
L
Linus Torvalds 已提交
1646 1647 1648

		if (size > SKB_MAX_ALLOC)
			size = SKB_MAX_ALLOC;
1649

L
Linus Torvalds 已提交
1650 1651 1652
		/*
		 *	Grab a buffer
		 */
1653

E
Eric Dumazet 已提交
1654 1655
		skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
					  &err);
L
Linus Torvalds 已提交
1656

1657
		if (skb == NULL)
L
Linus Torvalds 已提交
1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668
			goto out_err;

		/*
		 *	If you pass two values to the sock_alloc_send_skb
		 *	it tries to grab the large buffer with GFP_NOFS
		 *	(which can fail easily), and if it fails grab the
		 *	fallback size buffer which is under a page and will
		 *	succeed. [Alan]
		 */
		size = min_t(int, size, skb_tailroom(skb));

1669

1670 1671
		/* Only send the fds in the first buffer */
		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
E
Eric Dumazet 已提交
1672
		if (err < 0) {
1673
			kfree_skb(skb);
1674
			goto out_err;
1675
		}
E
Eric Dumazet 已提交
1676
		max_level = err + 1;
1677
		fds_sent = true;
L
Linus Torvalds 已提交
1678

E
Eric Dumazet 已提交
1679 1680
		err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
		if (err) {
L
Linus Torvalds 已提交
1681
			kfree_skb(skb);
1682
			goto out_err;
L
Linus Torvalds 已提交
1683 1684
		}

1685
		unix_state_lock(other);
L
Linus Torvalds 已提交
1686 1687 1688 1689 1690

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

1691
		maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1692
		skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1693 1694
		if (max_level > unix_sk(other)->recursion_level)
			unix_sk(other)->recursion_level = max_level;
1695
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1696
		other->sk_data_ready(other, size);
1697
		sent += size;
L
Linus Torvalds 已提交
1698 1699
	}

1700
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1701 1702 1703 1704 1705
	siocb->scm = NULL;

	return sent;

pipe_err_free:
1706
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1707 1708
	kfree_skb(skb);
pipe_err:
E
Eric Dumazet 已提交
1709 1710
	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
L
Linus Torvalds 已提交
1711 1712
	err = -EPIPE;
out_err:
1713
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1714 1715 1716 1717 1718 1719 1720 1721 1722
	siocb->scm = NULL;
	return sent ? : err;
}

static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
				  struct msghdr *msg, size_t len)
{
	int err;
	struct sock *sk = sock->sk;
1723

L
Linus Torvalds 已提交
1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735
	err = sock_error(sk);
	if (err)
		return err;

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

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

	return unix_dgram_sendmsg(kiocb, sock, msg, len);
}
1736

1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748
static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
			      struct msghdr *msg, size_t size,
			      int flags)
{
	struct sock *sk = sock->sk;

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

	return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
}

L
Linus Torvalds 已提交
1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770
static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
{
	struct unix_sock *u = unix_sk(sk);

	msg->msg_namelen = 0;
	if (u->addr) {
		msg->msg_namelen = u->addr->len;
		memcpy(msg->msg_name, u->addr->name, u->addr->len);
	}
}

static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
			      struct msghdr *msg, size_t size,
			      int flags)
{
	struct sock_iocb *siocb = kiocb_to_siocb(iocb);
	struct scm_cookie tmp_scm;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
	int noblock = flags & MSG_DONTWAIT;
	struct sk_buff *skb;
	int err;
1771
	int peeked, skip;
L
Linus Torvalds 已提交
1772 1773 1774 1775 1776 1777 1778

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

	msg->msg_namelen = 0;

1779 1780 1781 1782 1783
	err = mutex_lock_interruptible(&u->readlock);
	if (err) {
		err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
		goto out;
	}
L
Linus Torvalds 已提交
1784

1785 1786 1787
	skip = sk_peek_offset(sk, flags);

	skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1788 1789 1790 1791 1792 1793 1794
	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
1795
		goto out_unlock;
1796
	}
L
Linus Torvalds 已提交
1797

E
Eric Dumazet 已提交
1798 1799
	wake_up_interruptible_sync_poll(&u->peer_wait,
					POLLOUT | POLLWRNORM | POLLWRBAND);
L
Linus Torvalds 已提交
1800 1801 1802 1803

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

1804 1805 1806
	if (size > skb->len - skip)
		size = skb->len - skip;
	else if (size < skb->len - skip)
L
Linus Torvalds 已提交
1807 1808
		msg->msg_flags |= MSG_TRUNC;

1809
	err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size);
L
Linus Torvalds 已提交
1810 1811 1812
	if (err)
		goto out_free;

1813 1814 1815
	if (sock_flag(sk, SOCK_RCVTSTAMP))
		__sock_recv_timestamp(msg, sk, skb);

L
Linus Torvalds 已提交
1816 1817 1818 1819
	if (!siocb->scm) {
		siocb->scm = &tmp_scm;
		memset(&tmp_scm, 0, sizeof(tmp_scm));
	}
1820
	scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
C
Catherine Zhang 已提交
1821
	unix_set_secdata(siocb->scm, skb);
L
Linus Torvalds 已提交
1822

E
Eric Dumazet 已提交
1823
	if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
1824 1825
		if (UNIXCB(skb).fp)
			unix_detach_fds(siocb->scm, skb);
1826 1827

		sk_peek_offset_bwd(sk, skb->len);
E
Eric Dumazet 已提交
1828
	} else {
L
Linus Torvalds 已提交
1829 1830 1831 1832 1833 1834
		/* 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)
1835 1836 1837 1838 1839

		   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
1840
		*/
1841 1842 1843

		sk_peek_offset_fwd(sk, size);

L
Linus Torvalds 已提交
1844 1845 1846 1847 1848 1849 1850 1851
		if (UNIXCB(skb).fp)
			siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
	}
	err = size;

	scm_recv(sock, msg, siocb->scm, flags);

out_free:
E
Eric Dumazet 已提交
1852
	skb_free_datagram(sk, skb);
L
Linus Torvalds 已提交
1853
out_unlock:
I
Ingo Molnar 已提交
1854
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
1855 1856 1857 1858 1859 1860 1861
out:
	return err;
}

/*
 *	Sleep until data has arrive. But check for races..
 */
1862

E
Eric Dumazet 已提交
1863
static long unix_stream_data_wait(struct sock *sk, long timeo)
L
Linus Torvalds 已提交
1864 1865 1866
{
	DEFINE_WAIT(wait);

1867
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1868 1869

	for (;;) {
E
Eric Dumazet 已提交
1870
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
L
Linus Torvalds 已提交
1871

1872
		if (!skb_queue_empty(&sk->sk_receive_queue) ||
L
Linus Torvalds 已提交
1873 1874 1875 1876 1877 1878 1879
		    sk->sk_err ||
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
		    signal_pending(current) ||
		    !timeo)
			break;

		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1880
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1881
		timeo = schedule_timeout(timeo);
1882
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1883 1884 1885
		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
	}

E
Eric Dumazet 已提交
1886
	finish_wait(sk_sleep(sk), &wait);
1887
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900
	return timeo;
}



static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
			       struct msghdr *msg, size_t size,
			       int flags)
{
	struct sock_iocb *siocb = kiocb_to_siocb(iocb);
	struct scm_cookie tmp_scm;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
1901
	struct sockaddr_un *sunaddr = msg->msg_name;
L
Linus Torvalds 已提交
1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929
	int copied = 0;
	int check_creds = 0;
	int target;
	int err = 0;
	long timeo;

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

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

	target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
	timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);

	msg->msg_namelen = 0;

	/* Lock the socket to prevent queue disordering
	 * while sleeps in memcpy_tomsg
	 */

	if (!siocb->scm) {
		siocb->scm = &tmp_scm;
		memset(&tmp_scm, 0, sizeof(tmp_scm));
	}

1930 1931 1932 1933 1934
	err = mutex_lock_interruptible(&u->readlock);
	if (err) {
		err = sock_intr_errno(timeo);
		goto out;
	}
L
Linus Torvalds 已提交
1935

E
Eric Dumazet 已提交
1936
	do {
L
Linus Torvalds 已提交
1937 1938 1939
		int chunk;
		struct sk_buff *skb;

1940
		unix_state_lock(sk);
1941
		skb = skb_peek(&sk->sk_receive_queue);
E
Eric Dumazet 已提交
1942
		if (skb == NULL) {
E
Eric Dumazet 已提交
1943
			unix_sk(sk)->recursion_level = 0;
L
Linus Torvalds 已提交
1944
			if (copied >= target)
1945
				goto unlock;
L
Linus Torvalds 已提交
1946 1947 1948 1949

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
1950

E
Eric Dumazet 已提交
1951 1952
			err = sock_error(sk);
			if (err)
1953
				goto unlock;
L
Linus Torvalds 已提交
1954
			if (sk->sk_shutdown & RCV_SHUTDOWN)
1955 1956 1957
				goto unlock;

			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1958 1959 1960
			err = -EAGAIN;
			if (!timeo)
				break;
I
Ingo Molnar 已提交
1961
			mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
1962 1963 1964

			timeo = unix_stream_data_wait(sk, timeo);

1965 1966
			if (signal_pending(current)
			    ||  mutex_lock_interruptible(&u->readlock)) {
L
Linus Torvalds 已提交
1967 1968 1969
				err = sock_intr_errno(timeo);
				goto out;
			}
1970

L
Linus Torvalds 已提交
1971
			continue;
1972 1973 1974
 unlock:
			unix_state_unlock(sk);
			break;
L
Linus Torvalds 已提交
1975
		}
1976
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1977 1978 1979

		if (check_creds) {
			/* Never glue messages from different writers */
1980
			if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
1981
			    (UNIXCB(skb).cred != siocb->scm->cred))
L
Linus Torvalds 已提交
1982 1983 1984
				break;
		} else {
			/* Copy credentials */
1985
			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
L
Linus Torvalds 已提交
1986 1987 1988 1989
			check_creds = 1;
		}

		/* Copy address just once */
E
Eric Dumazet 已提交
1990
		if (sunaddr) {
L
Linus Torvalds 已提交
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
			unix_copy_addr(msg, skb->sk);
			sunaddr = NULL;
		}

		chunk = min_t(unsigned int, skb->len, size);
		if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

		/* Mark read part of skb as used */
E
Eric Dumazet 已提交
2005
		if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
2006 2007 2008 2009 2010
			skb_pull(skb, chunk);

			if (UNIXCB(skb).fp)
				unix_detach_fds(siocb->scm, skb);

2011
			if (skb->len)
L
Linus Torvalds 已提交
2012 2013
				break;

2014
			skb_unlink(skb, &sk->sk_receive_queue);
2015
			consume_skb(skb);
L
Linus Torvalds 已提交
2016 2017 2018

			if (siocb->scm->fp)
				break;
E
Eric Dumazet 已提交
2019
		} else {
L
Linus Torvalds 已提交
2020 2021 2022 2023 2024 2025 2026 2027 2028
			/* It is questionable, see note in unix_dgram_recvmsg.
			 */
			if (UNIXCB(skb).fp)
				siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);

			break;
		}
	} while (size);

I
Ingo Molnar 已提交
2029
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041
	scm_recv(sock, msg, siocb->scm, flags);
out:
	return copied ? : err;
}

static int unix_shutdown(struct socket *sock, int mode)
{
	struct sock *sk = sock->sk;
	struct sock *other;

	mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);

2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069
	if (!mode)
		return 0;

	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
2070
	}
2071 2072 2073
	if (other)
		sock_put(other);

L
Linus Torvalds 已提交
2074 2075 2076
	return 0;
}

2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106
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)
			amount += skb->len;
	} 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
2107 2108 2109
static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;
2110
	long amount = 0;
L
Linus Torvalds 已提交
2111 2112
	int err;

E
Eric Dumazet 已提交
2113 2114
	switch (cmd) {
	case SIOCOUTQ:
2115
		amount = unix_outq_len(sk);
E
Eric Dumazet 已提交
2116 2117 2118
		err = put_user(amount, (int __user *)arg);
		break;
	case SIOCINQ:
2119 2120 2121 2122
		amount = unix_inq_len(sk);
		if (amount < 0)
			err = amount;
		else
L
Linus Torvalds 已提交
2123
			err = put_user(amount, (int __user *)arg);
2124
		break;
E
Eric Dumazet 已提交
2125 2126 2127
	default:
		err = -ENOIOCTLCMD;
		break;
L
Linus Torvalds 已提交
2128 2129 2130 2131
	}
	return err;
}

E
Eric Dumazet 已提交
2132
static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
L
Linus Torvalds 已提交
2133 2134 2135 2136
{
	struct sock *sk = sock->sk;
	unsigned int mask;

E
Eric Dumazet 已提交
2137
	sock_poll_wait(file, sk_sleep(sk), wait);
L
Linus Torvalds 已提交
2138 2139 2140 2141 2142 2143 2144
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err)
		mask |= POLLERR;
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;
2145
	if (sk->sk_shutdown & RCV_SHUTDOWN)
E
Eric Dumazet 已提交
2146
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
L
Linus Torvalds 已提交
2147 2148

	/* readable? */
E
Eric Dumazet 已提交
2149
	if (!skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
2150 2151 2152
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
E
Eric Dumazet 已提交
2153 2154
	if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
	    sk->sk_state == TCP_CLOSE)
L
Linus Torvalds 已提交
2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166
		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;
}

2167 2168
static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
				    poll_table *wait)
2169
{
2170 2171
	struct sock *sk = sock->sk, *other;
	unsigned int mask, writable;
2172

E
Eric Dumazet 已提交
2173
	sock_poll_wait(file, sk_sleep(sk), wait);
2174 2175 2176 2177 2178 2179
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
		mask |= POLLERR;
	if (sk->sk_shutdown & RCV_SHUTDOWN)
2180
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2181 2182 2183 2184
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
2185
	if (!skb_queue_empty(&sk->sk_receive_queue))
2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196
		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
2197 2198 2199 2200
	/* No write status requested, avoid expensive OUT tests. */
	if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
		return mask;

2201
	writable = unix_writable(sk);
2202 2203 2204 2205 2206 2207
	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;
2208
		}
2209
		sock_put(other);
2210 2211 2212
	}

	if (writable)
2213 2214 2215 2216 2217 2218
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	return mask;
}
L
Linus Torvalds 已提交
2219 2220

#ifdef CONFIG_PROC_FS
2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243
static struct sock *first_unix_socket(int *i)
{
	for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
		if (!hlist_empty(&unix_socket_table[*i]))
			return __sk_head(&unix_socket_table[*i]);
	}
	return NULL;
}

static struct sock *next_unix_socket(int *i, struct sock *s)
{
	struct sock *next = sk_next(s);
	/* More in this chain? */
	if (next)
		return next;
	/* Look for next non-empty chain. */
	for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
		if (!hlist_empty(&unix_socket_table[*i]))
			return __sk_head(&unix_socket_table[*i]);
	}
	return NULL;
}

2244
struct unix_iter_state {
2245
	struct seq_net_private p;
2246 2247
	int i;
};
2248

2249
static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
L
Linus Torvalds 已提交
2250
{
2251
	struct unix_iter_state *iter = seq->private;
L
Linus Torvalds 已提交
2252 2253 2254
	loff_t off = 0;
	struct sock *s;

2255
	for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2256
		if (sock_net(s) != seq_file_net(seq))
2257
			continue;
2258
		if (off == pos)
L
Linus Torvalds 已提交
2259 2260 2261 2262 2263 2264 2265
			return s;
		++off;
	}
	return NULL;
}

static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2266
	__acquires(unix_table_lock)
L
Linus Torvalds 已提交
2267
{
2268
	spin_lock(&unix_table_lock);
J
Joe Perches 已提交
2269
	return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
L
Linus Torvalds 已提交
2270 2271 2272 2273
}

static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2274 2275
	struct unix_iter_state *iter = seq->private;
	struct sock *sk = v;
L
Linus Torvalds 已提交
2276 2277
	++*pos;

J
Joe Perches 已提交
2278
	if (v == SEQ_START_TOKEN)
2279 2280 2281
		sk = first_unix_socket(&iter->i);
	else
		sk = next_unix_socket(&iter->i, sk);
2282
	while (sk && (sock_net(sk) != seq_file_net(seq)))
2283 2284
		sk = next_unix_socket(&iter->i, sk);
	return sk;
L
Linus Torvalds 已提交
2285 2286 2287
}

static void unix_seq_stop(struct seq_file *seq, void *v)
2288
	__releases(unix_table_lock)
L
Linus Torvalds 已提交
2289
{
2290
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
2291 2292 2293 2294
}

static int unix_seq_show(struct seq_file *seq, void *v)
{
2295

J
Joe Perches 已提交
2296
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2297 2298 2299 2300 2301
		seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
			 "Inode Path\n");
	else {
		struct sock *s = v;
		struct unix_sock *u = unix_sk(s);
2302
		unix_state_lock(s);
L
Linus Torvalds 已提交
2303

D
Dan Rosenberg 已提交
2304
		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
L
Linus Torvalds 已提交
2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329
			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]);
		}
2330
		unix_state_unlock(s);
L
Linus Torvalds 已提交
2331 2332 2333 2334 2335 2336
		seq_putc(seq, '\n');
	}

	return 0;
}

2337
static const struct seq_operations unix_seq_ops = {
L
Linus Torvalds 已提交
2338 2339 2340 2341 2342 2343 2344 2345
	.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)
{
2346 2347
	return seq_open_net(inode, file, &unix_seq_ops,
			    sizeof(struct unix_iter_state));
L
Linus Torvalds 已提交
2348 2349
}

2350
static const struct file_operations unix_seq_fops = {
L
Linus Torvalds 已提交
2351 2352 2353 2354
	.owner		= THIS_MODULE,
	.open		= unix_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2355
	.release	= seq_release_net,
L
Linus Torvalds 已提交
2356 2357 2358 2359
};

#endif

2360
static const struct net_proto_family unix_family_ops = {
L
Linus Torvalds 已提交
2361 2362 2363 2364 2365
	.family = PF_UNIX,
	.create = unix_create,
	.owner	= THIS_MODULE,
};

2366

2367
static int __net_init unix_net_init(struct net *net)
2368 2369 2370
{
	int error = -ENOMEM;

2371
	net->unx.sysctl_max_dgram_qlen = 10;
2372 2373
	if (unix_sysctl_register(net))
		goto out;
2374

2375
#ifdef CONFIG_PROC_FS
2376 2377
	if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
		unix_sysctl_unregister(net);
2378
		goto out;
2379
	}
2380 2381 2382
#endif
	error = 0;
out:
2383
	return error;
2384 2385
}

2386
static void __net_exit unix_net_exit(struct net *net)
2387
{
2388
	unix_sysctl_unregister(net);
2389 2390 2391 2392 2393 2394 2395 2396
	proc_net_remove(net, "unix");
}

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

L
Linus Torvalds 已提交
2397 2398 2399 2400 2401
static int __init af_unix_init(void)
{
	int rc = -1;
	struct sk_buff *dummy_skb;

2402
	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
L
Linus Torvalds 已提交
2403 2404

	rc = proto_register(&unix_proto, 1);
2405 2406
	if (rc != 0) {
		printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2407
		       __func__);
L
Linus Torvalds 已提交
2408 2409 2410 2411
		goto out;
	}

	sock_register(&unix_family_ops);
2412
	register_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2413 2414 2415 2416 2417 2418 2419 2420
out:
	return rc;
}

static void __exit af_unix_exit(void)
{
	sock_unregister(PF_UNIX);
	proto_unregister(&unix_proto);
2421
	unregister_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2422 2423
}

2424 2425 2426 2427 2428
/* 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);
L
Linus Torvalds 已提交
2429 2430 2431 2432
module_exit(af_unix_exit);

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