af_unix.c 56.0 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 int unix_hash_fold(__wsum n)
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{
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	unsigned int hash = (__force unsigned int)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 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;
	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,
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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;
	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)]) {
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		struct dentry *dentry = unix_sk(s)->path.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);
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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	      */
		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 ---- */

	/*
	 * 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,
559
	.set_peek_off =	unix_set_peek_off,
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};

562
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,
571
	.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,
581
	.set_peek_off =	unix_set_peek_off,
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};

584
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,
593
	.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,
600
	.recvmsg =	unix_seqpacket_recvmsg,
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	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
603
	.set_peek_off =	unix_set_peek_off,
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};

static struct proto unix_proto = {
607 608 609
	.name			= "UNIX",
	.owner			= THIS_MODULE,
	.obj_size		= sizeof(struct unix_sock),
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};

612 613 614 615 616 617 618 619
/*
 * 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;

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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;

629
	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
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	if (!sk)
		goto out;

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	sock_init_data(sock, sk);
634 635
	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;
638
	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);
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	u->path.dentry = NULL;
	u->path.mnt = NULL;
643
	spin_lock_init(&u->lock);
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	atomic_long_set(&u->inflight, 0);
645
	INIT_LIST_HEAD(&u->link);
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	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:
650
	if (sk == NULL)
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Eric Dumazet 已提交
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		atomic_long_dec(&unix_nr_socks);
652 653
	else {
		local_bh_disable();
654
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
655 656
		local_bh_enable();
	}
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	return sk;
}

660 661
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:
677
		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;
	}

688
	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;

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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;
706
	struct net *net = sock_net(sk);
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	struct unix_sock *u = unix_sk(sk);
	static u32 ordernum = 1;
E
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	struct unix_address *addr;
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	int err;
711
	unsigned int retries = 0;
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712

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	mutex_lock(&u->readlock);
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714 715 716 717 718 719

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

	err = -ENOMEM;
720
	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);
729
	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
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731
	spin_lock(&unix_table_lock);
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	ordernum = (ordernum+1)&0xFFFFF;

734
	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
L
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				      addr->hash)) {
736
		spin_unlock(&unix_table_lock);
737 738 739 740 741 742 743 744 745 746 747
		/*
		 * __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);
755
	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;
}

762 763
static struct sock *unix_find_other(struct net *net,
				    struct sockaddr_un *sunname, int len,
764
				    int type, unsigned int hash, int *error)
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{
	struct sock *u;
767
	struct path path;
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768
	int err = 0;
769

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	if (sunname->sun_path[0]) {
771 772
		struct inode *inode;
		err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
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		if (err)
			goto fail;
775 776
		inode = path.dentry->d_inode;
		err = inode_permission(inode, MAY_WRITE);
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		if (err)
			goto put_fail;

		err = -ECONNREFUSED;
781
		if (!S_ISSOCK(inode->i_mode))
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			goto put_fail;
783
		u = unix_find_socket_byinode(inode);
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784 785 786 787
		if (!u)
			goto put_fail;

		if (u->sk_type == type)
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			touch_atime(&path);
L
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790
		path_put(&path);
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792
		err = -EPROTOTYPE;
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		if (u->sk_type != type) {
			sock_put(u);
			goto fail;
		}
	} else {
		err = -ECONNREFUSED;
799
		u = unix_find_socket_byname(net, sunname, len, type, hash);
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		if (u) {
			struct dentry *dentry;
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			dentry = unix_sk(u)->path.dentry;
L
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			if (dentry)
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				touch_atime(&unix_sk(u)->path);
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		} else
			goto fail;
	}
	return u;

put_fail:
811
	path_put(&path);
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fail:
813
	*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;
821
	struct net *net = sock_net(sk);
L
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	struct unix_sock *u = unix_sk(sk);
823
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
824
	char *sun_path = sunaddr->sun_path;
E
Eric Dumazet 已提交
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	struct dentry *dentry = NULL;
826
	struct path path;
L
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	int err;
828
	unsigned int hash;
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	struct unix_address *addr;
	struct hlist_head *list;

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

836
	if (addr_len == sizeof(short)) {
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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;

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Ingo Molnar 已提交
846
	mutex_lock(&u->readlock);
L
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847 848 849 850 851 852 853 854 855 856 857 858 859 860 861

	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);

862
	if (sun_path[0]) {
A
Al Viro 已提交
863
		umode_t mode;
L
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864 865 866 867 868
		err = 0;
		/*
		 * Get the parent directory, calculate the hash for last
		 * component.
		 */
869
		dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
L
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870 871
		err = PTR_ERR(dentry);
		if (IS_ERR(dentry))
872
			goto out_mknod_parent;
873

L
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874 875 876 877
		/*
		 * All right, let's create it.
		 */
		mode = S_IFSOCK |
A
Al Viro 已提交
878
		       (SOCK_INODE(sock)->i_mode & ~current_umask());
879
		err = mnt_want_write(path.mnt);
880 881
		if (err)
			goto out_mknod_dput;
882
		err = security_path_mknod(&path, dentry, mode, 0);
883 884
		if (err)
			goto out_mknod_drop_write;
885
		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
886
out_mknod_drop_write:
887
		mnt_drop_write(path.mnt);
L
Linus Torvalds 已提交
888 889
		if (err)
			goto out_mknod_dput;
890 891 892
		mutex_unlock(&path.dentry->d_inode->i_mutex);
		dput(path.dentry);
		path.dentry = dentry;
L
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		addr->hash = UNIX_HASH_SIZE;
	}

897
	spin_lock(&unix_table_lock);
L
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898

899
	if (!sun_path[0]) {
L
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900
		err = -EADDRINUSE;
901
		if (__unix_find_socket_byname(net, sunaddr, addr_len,
L
Linus Torvalds 已提交
902 903 904 905 906 907 908 909
					      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)];
A
Al Viro 已提交
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		u->path = path;
L
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911 912 913 914 915 916 917 918
	}

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

out_unlock:
919
	spin_unlock(&unix_table_lock);
L
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920
out_up:
I
Ingo Molnar 已提交
921
	mutex_unlock(&u->readlock);
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922 923 924 925 926
out:
	return err;

out_mknod_dput:
	dput(dentry);
927 928
	mutex_unlock(&path.dentry->d_inode->i_mutex);
	path_put(&path);
L
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929
out_mknod_parent:
930 931
	if (err == -EEXIST)
		err = -EADDRINUSE;
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	unix_release_addr(addr);
	goto out_up;
}

936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960
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);
}

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static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
			      int alen, int flags)
{
	struct sock *sk = sock->sk;
965
	struct net *net = sock_net(sk);
966
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
L
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967
	struct sock *other;
968
	unsigned int hash;
L
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969 970 971 972 973 974 975 976 977 978 979 980
	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;

981
restart:
982
		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
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983 984 985
		if (!other)
			goto out;

986 987 988 989 990 991 992 993
		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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		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;
1008
		unix_state_double_lock(sk, other);
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1009 1010 1011 1012 1013 1014 1015
	}

	/*
	 * If it was connected, reconnect.
	 */
	if (unix_peer(sk)) {
		struct sock *old_peer = unix_peer(sk);
1016
		unix_peer(sk) = other;
1017
		unix_state_double_unlock(sk, other);
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1018 1019 1020 1021 1022

		if (other != old_peer)
			unix_dgram_disconnected(sk, old_peer);
		sock_put(old_peer);
	} else {
1023
		unix_peer(sk) = other;
1024
		unix_state_double_unlock(sk, other);
L
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1025
	}
1026
	return 0;
L
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1027 1028

out_unlock:
1029
	unix_state_double_unlock(sk, other);
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1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044
	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) &&
1045
		unix_recvq_full(other);
L
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1046

1047
	unix_state_unlock(other);
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1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058

	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)
{
1059
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
L
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1060
	struct sock *sk = sock->sk;
1061
	struct net *net = sock_net(sk);
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1062 1063 1064 1065
	struct unix_sock *u = unix_sk(sk), *newu, *otheru;
	struct sock *newsk = NULL;
	struct sock *other = NULL;
	struct sk_buff *skb = NULL;
1066
	unsigned int hash;
L
Linus Torvalds 已提交
1067 1068 1069 1070 1071 1072 1073 1074 1075
	int st;
	int err;
	long timeo;

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

1076 1077
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
	    (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089
		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 */
1090
	newsk = unix_create1(sock_net(sk), NULL);
L
Linus Torvalds 已提交
1091 1092 1093 1094 1095 1096 1097 1098 1099 1100
	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. */
1101
	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
L
Linus Torvalds 已提交
1102 1103 1104 1105
	if (!other)
		goto out;

	/* Latch state of peer */
1106
	unix_state_lock(other);
L
Linus Torvalds 已提交
1107 1108 1109

	/* Apparently VFS overslept socket death. Retry. */
	if (sock_flag(other, SOCK_DEAD)) {
1110
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1111 1112 1113 1114 1115 1116 1117
		sock_put(other);
		goto restart;
	}

	err = -ECONNREFUSED;
	if (other->sk_state != TCP_LISTEN)
		goto out_unlock;
1118 1119
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;
L
Linus Torvalds 已提交
1120

1121
	if (unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132
		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;
1133
	}
L
Linus Torvalds 已提交
1134 1135 1136

	/* Latch our state.

D
Daniel Baluta 已提交
1137
	   It is tricky place. We need to grab our state lock and cannot
L
Linus Torvalds 已提交
1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160
	   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;
	}

1161
	unix_state_lock_nested(sk);
L
Linus Torvalds 已提交
1162 1163

	if (sk->sk_state != st) {
1164 1165
		unix_state_unlock(sk);
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1166 1167 1168 1169
		sock_put(other);
		goto restart;
	}

1170
	err = security_unix_stream_connect(sk, other, newsk);
L
Linus Torvalds 已提交
1171
	if (err) {
1172
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1173 1174 1175 1176 1177 1178 1179 1180 1181
		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;
1182
	init_peercred(newsk);
L
Linus Torvalds 已提交
1183
	newu = unix_sk(newsk);
1184
	RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
L
Linus Torvalds 已提交
1185 1186 1187 1188 1189 1190 1191
	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
1192 1193 1194
	if (otheru->path.dentry) {
		path_get(&otheru->path);
		newu->path = otheru->path;
L
Linus Torvalds 已提交
1195 1196 1197
	}

	/* Set credentials */
1198
	copy_peercred(sk, other);
L
Linus Torvalds 已提交
1199 1200 1201

	sock->state	= SS_CONNECTED;
	sk->sk_state	= TCP_ESTABLISHED;
1202 1203 1204 1205
	sock_hold(newsk);

	smp_mb__after_atomic_inc();	/* sock_hold() does an atomic_inc() */
	unix_peer(sk)	= newsk;
L
Linus Torvalds 已提交
1206

1207
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1208 1209 1210 1211 1212

	/* 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);
1213
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1214 1215 1216 1217 1218 1219
	other->sk_data_ready(other, 0);
	sock_put(other);
	return 0;

out_unlock:
	if (other)
1220
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1221 1222

out:
1223
	kfree_skb(skb);
L
Linus Torvalds 已提交
1224 1225 1226 1227 1228 1229 1230 1231 1232
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
1233
	struct sock *ska = socka->sk, *skb = sockb->sk;
L
Linus Torvalds 已提交
1234 1235 1236 1237

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
1238 1239
	unix_peer(ska) = skb;
	unix_peer(skb) = ska;
1240 1241
	init_peercred(ska);
	init_peercred(skb);
L
Linus Torvalds 已提交
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259

	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
1260
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
L
Linus Torvalds 已提交
1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283
		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 */
1284
	unix_state_lock(tsk);
L
Linus Torvalds 已提交
1285 1286
	newsock->state = SS_CONNECTED;
	sock_graft(tsk, newsock);
1287
	unix_state_unlock(tsk);
L
Linus Torvalds 已提交
1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298
	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;
1299
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
L
Linus Torvalds 已提交
1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313
	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);
1314
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1315 1316 1317 1318 1319 1320 1321 1322 1323 1324
	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);
	}
1325
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337
	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
1338
	for (i = scm->fp->count-1; i >= 0; i--)
L
Linus Torvalds 已提交
1339 1340 1341
		unix_notinflight(scm->fp->fp[i]);
}

1342
static void unix_destruct_scm(struct sk_buff *skb)
L
Linus Torvalds 已提交
1343 1344 1345
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
1346 1347 1348 1349
	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
1350 1351 1352 1353 1354 1355 1356

	/* 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
1357 1358
#define MAX_RECURSION_LEVEL 4

1359
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
L
Linus Torvalds 已提交
1360 1361
{
	int i;
E
Eric Dumazet 已提交
1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375
	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;
1376 1377 1378 1379 1380 1381 1382 1383 1384 1385

	/*
	 * 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
1386 1387 1388 1389 1390
	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
1391 1392
}

1393
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1394 1395
{
	int err = 0;
1396

1397
	UNIXCB(skb).pid  = get_pid(scm->pid);
1398 1399
	if (scm->cred)
		UNIXCB(skb).cred = get_cred(scm->cred);
1400 1401 1402 1403 1404 1405 1406 1407
	UNIXCB(skb).fp = NULL;
	if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

	skb->destructor = unix_destruct_scm;
	return err;
}

1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
/*
 * 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
1426 1427 1428 1429 1430 1431 1432 1433 1434
/*
 *	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;
1435
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1436
	struct unix_sock *u = unix_sk(sk);
1437
	struct sockaddr_un *sunaddr = msg->msg_name;
L
Linus Torvalds 已提交
1438 1439 1440
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
1441
	unsigned int hash;
1442
	struct sk_buff *skb;
L
Linus Torvalds 已提交
1443 1444
	long timeo;
	struct scm_cookie tmp_scm;
E
Eric Dumazet 已提交
1445
	int max_level;
1446
	int data_len = 0;
L
Linus Torvalds 已提交
1447 1448 1449

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1450
	wait_for_unix_gc();
L
Linus Torvalds 已提交
1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471
	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;
	}

1472 1473
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
	    && (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1474 1475 1476 1477 1478 1479
		goto out;

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

1480 1481 1482 1483 1484 1485 1486
	if (len > SKB_MAX_ALLOC)
		data_len = min_t(size_t,
				 len - SKB_MAX_ALLOC,
				 MAX_SKB_FRAGS * PAGE_SIZE);

	skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
				   msg->msg_flags & MSG_DONTWAIT, &err);
1487
	if (skb == NULL)
L
Linus Torvalds 已提交
1488 1489
		goto out;

1490
	err = unix_scm_to_skb(siocb->scm, skb, true);
E
Eric Dumazet 已提交
1491
	if (err < 0)
1492
		goto out_free;
E
Eric Dumazet 已提交
1493
	max_level = err + 1;
1494
	unix_get_secdata(siocb->scm, skb);
C
Catherine Zhang 已提交
1495

1496 1497 1498 1499
	skb_put(skb, len - data_len);
	skb->data_len = data_len;
	skb->len = len;
	err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len);
L
Linus Torvalds 已提交
1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510
	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;

1511
		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
L
Linus Torvalds 已提交
1512
					hash, &err);
1513
		if (other == NULL)
L
Linus Torvalds 已提交
1514 1515 1516
			goto out_free;
	}

A
Alban Crequy 已提交
1517 1518 1519 1520 1521 1522
	if (sk_filter(other, skb) < 0) {
		/* Toss the packet but do not return any error to the sender */
		err = len;
		goto out_free;
	}

1523
	unix_state_lock(other);
L
Linus Torvalds 已提交
1524 1525 1526 1527 1528 1529 1530 1531 1532
	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
		 */
1533
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1534 1535 1536
		sock_put(other);

		err = 0;
1537
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1538
		if (unix_peer(sk) == other) {
1539
			unix_peer(sk) = NULL;
1540
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1541 1542 1543 1544 1545

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
1546
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564
		}

		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;
	}

1565
	if (unix_peer(other) != sk && unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
		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;
	}

1580 1581
	if (sock_flag(other, SOCK_RCVTSTAMP))
		__net_timestamp(skb);
1582
	maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1583
	skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1584 1585
	if (max_level > unix_sk(other)->recursion_level)
		unix_sk(other)->recursion_level = max_level;
1586
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1587 1588
	other->sk_data_ready(other, len);
	sock_put(other);
1589
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1590 1591 1592
	return len;

out_unlock:
1593
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1594 1595 1596 1597 1598
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
1599
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1600 1601 1602
	return err;
}

1603

L
Linus Torvalds 已提交
1604 1605 1606 1607 1608 1609
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
1610
	int err, size;
1611
	struct sk_buff *skb;
1612
	int sent = 0;
L
Linus Torvalds 已提交
1613
	struct scm_cookie tmp_scm;
1614
	bool fds_sent = false;
E
Eric Dumazet 已提交
1615
	int max_level;
L
Linus Torvalds 已提交
1616 1617 1618

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1619
	wait_for_unix_gc();
L
Linus Torvalds 已提交
1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632
	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;
1633
		other = unix_peer(sk);
L
Linus Torvalds 已提交
1634 1635 1636 1637 1638 1639 1640
		if (!other)
			goto out_err;
	}

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

E
Eric Dumazet 已提交
1641
	while (sent < len) {
L
Linus Torvalds 已提交
1642
		/*
1643 1644
		 *	Optimisation for the fact that under 0.01% of X
		 *	messages typically need breaking up.
L
Linus Torvalds 已提交
1645 1646
		 */

1647
		size = len-sent;
L
Linus Torvalds 已提交
1648 1649

		/* Keep two messages in the pipe so it schedules better */
1650 1651
		if (size > ((sk->sk_sndbuf >> 1) - 64))
			size = (sk->sk_sndbuf >> 1) - 64;
L
Linus Torvalds 已提交
1652 1653 1654

		if (size > SKB_MAX_ALLOC)
			size = SKB_MAX_ALLOC;
1655

L
Linus Torvalds 已提交
1656 1657 1658
		/*
		 *	Grab a buffer
		 */
1659

E
Eric Dumazet 已提交
1660 1661
		skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
					  &err);
L
Linus Torvalds 已提交
1662

1663
		if (skb == NULL)
L
Linus Torvalds 已提交
1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674
			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));

1675

1676 1677
		/* Only send the fds in the first buffer */
		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
E
Eric Dumazet 已提交
1678
		if (err < 0) {
1679
			kfree_skb(skb);
1680
			goto out_err;
1681
		}
E
Eric Dumazet 已提交
1682
		max_level = err + 1;
1683
		fds_sent = true;
L
Linus Torvalds 已提交
1684

E
Eric Dumazet 已提交
1685 1686
		err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
		if (err) {
L
Linus Torvalds 已提交
1687
			kfree_skb(skb);
1688
			goto out_err;
L
Linus Torvalds 已提交
1689 1690
		}

1691
		unix_state_lock(other);
L
Linus Torvalds 已提交
1692 1693 1694 1695 1696

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

1697
		maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1698
		skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1699 1700
		if (max_level > unix_sk(other)->recursion_level)
			unix_sk(other)->recursion_level = max_level;
1701
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1702
		other->sk_data_ready(other, size);
1703
		sent += size;
L
Linus Torvalds 已提交
1704 1705
	}

1706
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1707 1708 1709 1710 1711
	siocb->scm = NULL;

	return sent;

pipe_err_free:
1712
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1713 1714
	kfree_skb(skb);
pipe_err:
E
Eric Dumazet 已提交
1715 1716
	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
L
Linus Torvalds 已提交
1717 1718
	err = -EPIPE;
out_err:
1719
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1720 1721 1722 1723 1724 1725 1726 1727 1728
	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;
1729

L
Linus Torvalds 已提交
1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741
	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);
}
1742

1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754
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
1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776
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;
1777
	int peeked, skip;
L
Linus Torvalds 已提交
1778 1779 1780 1781 1782 1783 1784

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

	msg->msg_namelen = 0;

1785 1786 1787 1788 1789
	err = mutex_lock_interruptible(&u->readlock);
	if (err) {
		err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
		goto out;
	}
L
Linus Torvalds 已提交
1790

1791 1792 1793
	skip = sk_peek_offset(sk, flags);

	skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1794 1795 1796 1797 1798 1799 1800
	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
1801
		goto out_unlock;
1802
	}
L
Linus Torvalds 已提交
1803

E
Eric Dumazet 已提交
1804 1805
	wake_up_interruptible_sync_poll(&u->peer_wait,
					POLLOUT | POLLWRNORM | POLLWRBAND);
L
Linus Torvalds 已提交
1806 1807 1808 1809

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

1810 1811 1812
	if (size > skb->len - skip)
		size = skb->len - skip;
	else if (size < skb->len - skip)
L
Linus Torvalds 已提交
1813 1814
		msg->msg_flags |= MSG_TRUNC;

1815
	err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size);
L
Linus Torvalds 已提交
1816 1817 1818
	if (err)
		goto out_free;

1819 1820 1821
	if (sock_flag(sk, SOCK_RCVTSTAMP))
		__sock_recv_timestamp(msg, sk, skb);

L
Linus Torvalds 已提交
1822 1823 1824 1825
	if (!siocb->scm) {
		siocb->scm = &tmp_scm;
		memset(&tmp_scm, 0, sizeof(tmp_scm));
	}
1826
	scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
C
Catherine Zhang 已提交
1827
	unix_set_secdata(siocb->scm, skb);
L
Linus Torvalds 已提交
1828

E
Eric Dumazet 已提交
1829
	if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
1830 1831
		if (UNIXCB(skb).fp)
			unix_detach_fds(siocb->scm, skb);
1832 1833

		sk_peek_offset_bwd(sk, skb->len);
E
Eric Dumazet 已提交
1834
	} else {
L
Linus Torvalds 已提交
1835 1836 1837 1838 1839 1840
		/* 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)
1841 1842 1843 1844 1845

		   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
1846
		*/
1847 1848 1849

		sk_peek_offset_fwd(sk, size);

L
Linus Torvalds 已提交
1850 1851 1852
		if (UNIXCB(skb).fp)
			siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
	}
1853
	err = (flags & MSG_TRUNC) ? skb->len - skip : size;
L
Linus Torvalds 已提交
1854 1855 1856 1857

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

out_free:
E
Eric Dumazet 已提交
1858
	skb_free_datagram(sk, skb);
L
Linus Torvalds 已提交
1859
out_unlock:
I
Ingo Molnar 已提交
1860
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
1861 1862 1863 1864 1865 1866 1867
out:
	return err;
}

/*
 *	Sleep until data has arrive. But check for races..
 */
1868

E
Eric Dumazet 已提交
1869
static long unix_stream_data_wait(struct sock *sk, long timeo)
L
Linus Torvalds 已提交
1870 1871 1872
{
	DEFINE_WAIT(wait);

1873
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1874 1875

	for (;;) {
E
Eric Dumazet 已提交
1876
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
L
Linus Torvalds 已提交
1877

1878
		if (!skb_queue_empty(&sk->sk_receive_queue) ||
L
Linus Torvalds 已提交
1879 1880 1881 1882 1883 1884 1885
		    sk->sk_err ||
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
		    signal_pending(current) ||
		    !timeo)
			break;

		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1886
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1887
		timeo = schedule_timeout(timeo);
1888
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1889 1890 1891
		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
	}

E
Eric Dumazet 已提交
1892
	finish_wait(sk_sleep(sk), &wait);
1893
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906
	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);
1907
	struct sockaddr_un *sunaddr = msg->msg_name;
L
Linus Torvalds 已提交
1908 1909 1910 1911 1912
	int copied = 0;
	int check_creds = 0;
	int target;
	int err = 0;
	long timeo;
1913
	int skip;
L
Linus Torvalds 已提交
1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936

	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));
	}

1937 1938 1939 1940 1941
	err = mutex_lock_interruptible(&u->readlock);
	if (err) {
		err = sock_intr_errno(timeo);
		goto out;
	}
L
Linus Torvalds 已提交
1942

1943 1944
	skip = sk_peek_offset(sk, flags);

E
Eric Dumazet 已提交
1945
	do {
L
Linus Torvalds 已提交
1946 1947 1948
		int chunk;
		struct sk_buff *skb;

1949
		unix_state_lock(sk);
1950
		skb = skb_peek(&sk->sk_receive_queue);
1951
again:
E
Eric Dumazet 已提交
1952
		if (skb == NULL) {
E
Eric Dumazet 已提交
1953
			unix_sk(sk)->recursion_level = 0;
L
Linus Torvalds 已提交
1954
			if (copied >= target)
1955
				goto unlock;
L
Linus Torvalds 已提交
1956 1957 1958 1959

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
1960

E
Eric Dumazet 已提交
1961 1962
			err = sock_error(sk);
			if (err)
1963
				goto unlock;
L
Linus Torvalds 已提交
1964
			if (sk->sk_shutdown & RCV_SHUTDOWN)
1965 1966 1967
				goto unlock;

			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1968 1969 1970
			err = -EAGAIN;
			if (!timeo)
				break;
I
Ingo Molnar 已提交
1971
			mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
1972 1973 1974

			timeo = unix_stream_data_wait(sk, timeo);

1975 1976
			if (signal_pending(current)
			    ||  mutex_lock_interruptible(&u->readlock)) {
L
Linus Torvalds 已提交
1977 1978 1979
				err = sock_intr_errno(timeo);
				goto out;
			}
1980

L
Linus Torvalds 已提交
1981
			continue;
1982 1983 1984
 unlock:
			unix_state_unlock(sk);
			break;
L
Linus Torvalds 已提交
1985
		}
1986 1987 1988 1989 1990 1991 1992

		if (skip >= skb->len) {
			skip -= skb->len;
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
			goto again;
		}

1993
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1994 1995 1996

		if (check_creds) {
			/* Never glue messages from different writers */
1997
			if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
1998
			    (UNIXCB(skb).cred != siocb->scm->cred))
L
Linus Torvalds 已提交
1999 2000 2001
				break;
		} else {
			/* Copy credentials */
2002
			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
L
Linus Torvalds 已提交
2003 2004 2005 2006
			check_creds = 1;
		}

		/* Copy address just once */
E
Eric Dumazet 已提交
2007
		if (sunaddr) {
L
Linus Torvalds 已提交
2008 2009 2010 2011
			unix_copy_addr(msg, skb->sk);
			sunaddr = NULL;
		}

2012 2013
		chunk = min_t(unsigned int, skb->len - skip, size);
		if (memcpy_toiovec(msg->msg_iov, skb->data + skip, chunk)) {
L
Linus Torvalds 已提交
2014 2015 2016 2017 2018 2019 2020 2021
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

		/* Mark read part of skb as used */
E
Eric Dumazet 已提交
2022
		if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
2023 2024
			skb_pull(skb, chunk);

2025 2026
			sk_peek_offset_bwd(sk, chunk);

L
Linus Torvalds 已提交
2027 2028 2029
			if (UNIXCB(skb).fp)
				unix_detach_fds(siocb->scm, skb);

2030
			if (skb->len)
L
Linus Torvalds 已提交
2031 2032
				break;

2033
			skb_unlink(skb, &sk->sk_receive_queue);
2034
			consume_skb(skb);
L
Linus Torvalds 已提交
2035 2036 2037

			if (siocb->scm->fp)
				break;
E
Eric Dumazet 已提交
2038
		} else {
L
Linus Torvalds 已提交
2039 2040 2041 2042 2043
			/* It is questionable, see note in unix_dgram_recvmsg.
			 */
			if (UNIXCB(skb).fp)
				siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);

2044 2045
			sk_peek_offset_fwd(sk, chunk);

L
Linus Torvalds 已提交
2046 2047 2048 2049
			break;
		}
	} while (size);

I
Ingo Molnar 已提交
2050
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062
	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);

2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090
	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
2091
	}
2092 2093 2094
	if (other)
		sock_put(other);

L
Linus Torvalds 已提交
2095 2096 2097
	return 0;
}

2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127
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
2128 2129 2130
static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;
2131
	long amount = 0;
L
Linus Torvalds 已提交
2132 2133
	int err;

E
Eric Dumazet 已提交
2134 2135
	switch (cmd) {
	case SIOCOUTQ:
2136
		amount = unix_outq_len(sk);
E
Eric Dumazet 已提交
2137 2138 2139
		err = put_user(amount, (int __user *)arg);
		break;
	case SIOCINQ:
2140 2141 2142 2143
		amount = unix_inq_len(sk);
		if (amount < 0)
			err = amount;
		else
L
Linus Torvalds 已提交
2144
			err = put_user(amount, (int __user *)arg);
2145
		break;
E
Eric Dumazet 已提交
2146 2147 2148
	default:
		err = -ENOIOCTLCMD;
		break;
L
Linus Torvalds 已提交
2149 2150 2151 2152
	}
	return err;
}

E
Eric Dumazet 已提交
2153
static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
L
Linus Torvalds 已提交
2154 2155 2156 2157
{
	struct sock *sk = sock->sk;
	unsigned int mask;

E
Eric Dumazet 已提交
2158
	sock_poll_wait(file, sk_sleep(sk), wait);
L
Linus Torvalds 已提交
2159 2160 2161 2162 2163 2164 2165
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err)
		mask |= POLLERR;
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;
2166
	if (sk->sk_shutdown & RCV_SHUTDOWN)
E
Eric Dumazet 已提交
2167
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
L
Linus Torvalds 已提交
2168 2169

	/* readable? */
E
Eric Dumazet 已提交
2170
	if (!skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
2171 2172 2173
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
E
Eric Dumazet 已提交
2174 2175
	if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
	    sk->sk_state == TCP_CLOSE)
L
Linus Torvalds 已提交
2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187
		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;
}

2188 2189
static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
				    poll_table *wait)
2190
{
2191 2192
	struct sock *sk = sock->sk, *other;
	unsigned int mask, writable;
2193

E
Eric Dumazet 已提交
2194
	sock_poll_wait(file, sk_sleep(sk), wait);
2195 2196 2197 2198 2199 2200
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
		mask |= POLLERR;
	if (sk->sk_shutdown & RCV_SHUTDOWN)
2201
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2202 2203 2204 2205
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
2206
	if (!skb_queue_empty(&sk->sk_receive_queue))
2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217
		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
2218
	/* No write status requested, avoid expensive OUT tests. */
2219
	if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
E
Eric Dumazet 已提交
2220 2221
		return mask;

2222
	writable = unix_writable(sk);
2223 2224 2225 2226 2227 2228
	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;
2229
		}
2230
		sock_put(other);
2231 2232 2233
	}

	if (writable)
2234 2235 2236 2237 2238 2239
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	return mask;
}
L
Linus Torvalds 已提交
2240 2241

#ifdef CONFIG_PROC_FS
2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264
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;
}

2265
struct unix_iter_state {
2266
	struct seq_net_private p;
2267 2268
	int i;
};
2269

2270
static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
L
Linus Torvalds 已提交
2271
{
2272
	struct unix_iter_state *iter = seq->private;
L
Linus Torvalds 已提交
2273 2274 2275
	loff_t off = 0;
	struct sock *s;

2276
	for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2277
		if (sock_net(s) != seq_file_net(seq))
2278
			continue;
2279
		if (off == pos)
L
Linus Torvalds 已提交
2280 2281 2282 2283 2284 2285 2286
			return s;
		++off;
	}
	return NULL;
}

static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2287
	__acquires(unix_table_lock)
L
Linus Torvalds 已提交
2288
{
2289
	spin_lock(&unix_table_lock);
J
Joe Perches 已提交
2290
	return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
L
Linus Torvalds 已提交
2291 2292 2293 2294
}

static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2295 2296
	struct unix_iter_state *iter = seq->private;
	struct sock *sk = v;
L
Linus Torvalds 已提交
2297 2298
	++*pos;

J
Joe Perches 已提交
2299
	if (v == SEQ_START_TOKEN)
2300 2301 2302
		sk = first_unix_socket(&iter->i);
	else
		sk = next_unix_socket(&iter->i, sk);
2303
	while (sk && (sock_net(sk) != seq_file_net(seq)))
2304 2305
		sk = next_unix_socket(&iter->i, sk);
	return sk;
L
Linus Torvalds 已提交
2306 2307 2308
}

static void unix_seq_stop(struct seq_file *seq, void *v)
2309
	__releases(unix_table_lock)
L
Linus Torvalds 已提交
2310
{
2311
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
2312 2313 2314 2315
}

static int unix_seq_show(struct seq_file *seq, void *v)
{
2316

J
Joe Perches 已提交
2317
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2318 2319 2320 2321 2322
		seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
			 "Inode Path\n");
	else {
		struct sock *s = v;
		struct unix_sock *u = unix_sk(s);
2323
		unix_state_lock(s);
L
Linus Torvalds 已提交
2324

D
Dan Rosenberg 已提交
2325
		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
L
Linus Torvalds 已提交
2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350
			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]);
		}
2351
		unix_state_unlock(s);
L
Linus Torvalds 已提交
2352 2353 2354 2355 2356 2357
		seq_putc(seq, '\n');
	}

	return 0;
}

2358
static const struct seq_operations unix_seq_ops = {
L
Linus Torvalds 已提交
2359 2360 2361 2362 2363 2364 2365 2366
	.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)
{
2367 2368
	return seq_open_net(inode, file, &unix_seq_ops,
			    sizeof(struct unix_iter_state));
L
Linus Torvalds 已提交
2369 2370
}

2371
static const struct file_operations unix_seq_fops = {
L
Linus Torvalds 已提交
2372 2373 2374 2375
	.owner		= THIS_MODULE,
	.open		= unix_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2376
	.release	= seq_release_net,
L
Linus Torvalds 已提交
2377 2378 2379 2380
};

#endif

2381
static const struct net_proto_family unix_family_ops = {
L
Linus Torvalds 已提交
2382 2383 2384 2385 2386
	.family = PF_UNIX,
	.create = unix_create,
	.owner	= THIS_MODULE,
};

2387

2388
static int __net_init unix_net_init(struct net *net)
2389 2390 2391
{
	int error = -ENOMEM;

2392
	net->unx.sysctl_max_dgram_qlen = 10;
2393 2394
	if (unix_sysctl_register(net))
		goto out;
2395

2396
#ifdef CONFIG_PROC_FS
2397 2398
	if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
		unix_sysctl_unregister(net);
2399
		goto out;
2400
	}
2401 2402 2403
#endif
	error = 0;
out:
2404
	return error;
2405 2406
}

2407
static void __net_exit unix_net_exit(struct net *net)
2408
{
2409
	unix_sysctl_unregister(net);
2410 2411 2412 2413 2414 2415 2416 2417
	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
2418 2419 2420 2421 2422
static int __init af_unix_init(void)
{
	int rc = -1;
	struct sk_buff *dummy_skb;

2423
	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
L
Linus Torvalds 已提交
2424 2425

	rc = proto_register(&unix_proto, 1);
2426 2427
	if (rc != 0) {
		printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2428
		       __func__);
L
Linus Torvalds 已提交
2429 2430 2431 2432
		goto out;
	}

	sock_register(&unix_family_ops);
2433
	register_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2434 2435 2436 2437 2438 2439 2440 2441
out:
	return rc;
}

static void __exit af_unix_exit(void)
{
	sock_unregister(PF_UNIX);
	proto_unregister(&unix_proto);
2442
	unregister_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2443 2444
}

2445 2446 2447 2448 2449
/* 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
2450 2451 2452 2453
module_exit(af_unix_exit);

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