af_unix.c 56.4 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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#include <linux/freezer.h>
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struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
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EXPORT_SYMBOL_GPL(unix_socket_table);
DEFINE_SPINLOCK(unix_table_lock);
EXPORT_SYMBOL_GPL(unix_table_lock);
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static atomic_long_t unix_nr_socks;
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static struct hlist_head *unix_sockets_unbound(void *addr)
{
	unsigned long hash = (unsigned long)addr;

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

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

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

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

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

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

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

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

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	spin_lock(&unix_table_lock);
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	sk_for_each(s,
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		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
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		struct dentry *dentry = unix_sk(s)->path.dentry;
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		if (dentry && 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 void unix_release_sock(struct sock *sk, int embrion)
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{
	struct unix_sock *u = unix_sk(sk);
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	struct path path;
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	struct sock *skpair;
	struct sk_buff *skb;
	int state;

	unix_remove_socket(sk);

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

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

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

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

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

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

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

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

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

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

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

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

static int unix_release(struct socket *);
static int unix_bind(struct socket *, struct sockaddr *, int);
static int unix_stream_connect(struct socket *, struct sockaddr *,
			       int addr_len, int flags);
static int unix_socketpair(struct socket *, struct socket *);
static int unix_accept(struct socket *, struct socket *, int);
static int unix_getname(struct socket *, struct sockaddr *, int *, int);
static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
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static unsigned int unix_dgram_poll(struct file *, struct socket *,
				    poll_table *);
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static int unix_ioctl(struct socket *, unsigned int, unsigned long);
static int unix_shutdown(struct socket *, int);
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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533 534 535 536 537 538 539 540 541 542
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);
}


543
static const struct proto_ops unix_stream_ops = {
L
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	.family =	PF_UNIX,
	.owner =	THIS_MODULE,
	.release =	unix_release,
	.bind =		unix_bind,
	.connect =	unix_stream_connect,
	.socketpair =	unix_socketpair,
	.accept =	unix_accept,
	.getname =	unix_getname,
	.poll =		unix_poll,
	.ioctl =	unix_ioctl,
	.listen =	unix_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_stream_sendmsg,
	.recvmsg =	unix_stream_recvmsg,
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
562
	.set_peek_off =	unix_set_peek_off,
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};

565
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,
574
	.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,
584
	.set_peek_off =	unix_set_peek_off,
L
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};

587
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,
596
	.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,
603
	.recvmsg =	unix_seqpacket_recvmsg,
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	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
606
	.set_peek_off =	unix_set_peek_off,
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};

static struct proto unix_proto = {
610 611 612
	.name			= "UNIX",
	.owner			= THIS_MODULE,
	.obj_size		= sizeof(struct unix_sock),
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};

615 616 617 618 619 620 621 622
/*
 * 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;

E
Eric Dumazet 已提交
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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;

632
	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
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	if (!sk)
		goto out;

E
Eric Dumazet 已提交
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	sock_init_data(sock, sk);
637 638
	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;
641
	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;
646
	spin_lock_init(&u->lock);
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	atomic_long_set(&u->inflight, 0);
648
	INIT_LIST_HEAD(&u->link);
I
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649
	mutex_init(&u->readlock); /* single task reading lock */
L
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	init_waitqueue_head(&u->peer_wait);
E
Eric Dumazet 已提交
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	unix_insert_socket(unix_sockets_unbound(sk), sk);
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out:
653
	if (sk == NULL)
E
Eric Dumazet 已提交
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		atomic_long_dec(&unix_nr_socks);
655 656
	else {
		local_bh_disable();
657
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
658 659
		local_bh_enable();
	}
L
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	return sk;
}

663 664
static int unix_create(struct net *net, struct socket *sock, int protocol,
		       int kern)
L
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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:
680
		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;
	}

691
	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;

701
	unix_release_sock(sk, 0);
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	sock->sk = NULL;

704
	return 0;
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}

static int unix_autobind(struct socket *sock)
{
	struct sock *sk = sock->sk;
710
	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
713
	struct unix_address *addr;
L
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714
	int err;
715
	unsigned int retries = 0;
L
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716

I
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	mutex_lock(&u->readlock);
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718 719 720 721 722 723

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

	err = -ENOMEM;
724
	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);
733
	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
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734

735
	spin_lock(&unix_table_lock);
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	ordernum = (ordernum+1)&0xFFFFF;

738
	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
L
Linus Torvalds 已提交
739
				      addr->hash)) {
740
		spin_unlock(&unix_table_lock);
741 742 743 744 745 746 747 748 749 750 751
		/*
		 * __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);
759
	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;
}

766 767
static struct sock *unix_find_other(struct net *net,
				    struct sockaddr_un *sunname, int len,
768
				    int type, unsigned int hash, int *error)
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{
	struct sock *u;
771
	struct path path;
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	int err = 0;
773

L
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	if (sunname->sun_path[0]) {
775 776
		struct inode *inode;
		err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
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		if (err)
			goto fail;
779 780
		inode = path.dentry->d_inode;
		err = inode_permission(inode, MAY_WRITE);
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		if (err)
			goto put_fail;

		err = -ECONNREFUSED;
785
		if (!S_ISSOCK(inode->i_mode))
L
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			goto put_fail;
787
		u = unix_find_socket_byinode(inode);
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788 789 790 791
		if (!u)
			goto put_fail;

		if (u->sk_type == type)
A
Al Viro 已提交
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			touch_atime(&path);
L
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793

794
		path_put(&path);
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795

796
		err = -EPROTOTYPE;
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		if (u->sk_type != type) {
			sock_put(u);
			goto fail;
		}
	} else {
		err = -ECONNREFUSED;
803
		u = unix_find_socket_byname(net, sunname, len, type, hash);
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		if (u) {
			struct dentry *dentry;
A
Al Viro 已提交
806
			dentry = unix_sk(u)->path.dentry;
L
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			if (dentry)
A
Al Viro 已提交
808
				touch_atime(&unix_sk(u)->path);
L
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		} else
			goto fail;
	}
	return u;

put_fail:
815
	path_put(&path);
L
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fail:
817
	*error = err;
L
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	return NULL;
}

A
Al Viro 已提交
821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848
static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
{
	struct dentry *dentry;
	struct path path;
	int err = 0;
	/*
	 * Get the parent directory, calculate the hash for last
	 * component.
	 */
	dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
	err = PTR_ERR(dentry);
	if (IS_ERR(dentry))
		return err;

	/*
	 * All right, let's create it.
	 */
	err = security_path_mknod(&path, dentry, mode, 0);
	if (!err) {
		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
		if (!err) {
			res->mnt = mntget(path.mnt);
			res->dentry = dget(dentry);
		}
	}
	done_path_create(&path, dentry);
	return err;
}
L
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static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sock *sk = sock->sk;
853
	struct net *net = sock_net(sk);
L
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854
	struct unix_sock *u = unix_sk(sk);
855
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
856
	char *sun_path = sunaddr->sun_path;
L
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857
	int err;
858
	unsigned int hash;
L
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859 860 861 862 863 864 865
	struct unix_address *addr;
	struct hlist_head *list;

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

866
	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
876
	mutex_lock(&u->readlock);
L
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877 878 879 880 881 882 883 884 885 886 887 888 889 890 891

	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);

892
	if (sun_path[0]) {
A
Al Viro 已提交
893 894
		struct path path;
		umode_t mode = S_IFSOCK |
A
Al Viro 已提交
895
		       (SOCK_INODE(sock)->i_mode & ~current_umask());
A
Al Viro 已提交
896 897 898 899 900 901 902
		err = unix_mknod(sun_path, mode, &path);
		if (err) {
			if (err == -EEXIST)
				err = -EADDRINUSE;
			unix_release_addr(addr);
			goto out_up;
		}
L
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903
		addr->hash = UNIX_HASH_SIZE;
A
Al Viro 已提交
904 905 906 907 908 909
		hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1);
		spin_lock(&unix_table_lock);
		u->path = path;
		list = &unix_socket_table[hash];
	} else {
		spin_lock(&unix_table_lock);
L
Linus Torvalds 已提交
910
		err = -EADDRINUSE;
911
		if (__unix_find_socket_byname(net, sunaddr, addr_len,
L
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912 913 914 915 916 917 918 919 920 921 922 923 924 925
					      sk->sk_type, hash)) {
			unix_release_addr(addr);
			goto out_unlock;
		}

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

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

out_unlock:
926
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
927
out_up:
I
Ingo Molnar 已提交
928
	mutex_unlock(&u->readlock);
L
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929 930 931 932
out:
	return err;
}

933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957
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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static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
			      int alen, int flags)
{
	struct sock *sk = sock->sk;
962
	struct net *net = sock_net(sk);
963
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
L
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964
	struct sock *other;
965
	unsigned int hash;
L
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966 967 968 969 970 971 972 973 974 975 976 977
	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;

978
restart:
979
		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
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980 981 982
		if (!other)
			goto out;

983 984 985 986 987 988 989 990
		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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991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004

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

	/*
	 * If it was connected, reconnect.
	 */
	if (unix_peer(sk)) {
		struct sock *old_peer = unix_peer(sk);
1013
		unix_peer(sk) = other;
1014
		unix_state_double_unlock(sk, other);
L
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1015 1016 1017 1018 1019

		if (other != old_peer)
			unix_dgram_disconnected(sk, old_peer);
		sock_put(old_peer);
	} else {
1020
		unix_peer(sk) = other;
1021
		unix_state_double_unlock(sk, other);
L
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1022
	}
1023
	return 0;
L
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1024 1025

out_unlock:
1026
	unix_state_double_unlock(sk, other);
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1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041
	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) &&
1042
		unix_recvq_full(other);
L
Linus Torvalds 已提交
1043

1044
	unix_state_unlock(other);
L
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1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055

	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)
{
1056
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
L
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1057
	struct sock *sk = sock->sk;
1058
	struct net *net = sock_net(sk);
L
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1059 1060 1061 1062
	struct unix_sock *u = unix_sk(sk), *newu, *otheru;
	struct sock *newsk = NULL;
	struct sock *other = NULL;
	struct sk_buff *skb = NULL;
1063
	unsigned int hash;
L
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1064 1065 1066 1067 1068 1069 1070 1071 1072
	int st;
	int err;
	long timeo;

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

1073 1074
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
	    (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086
		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 */
1087
	newsk = unix_create1(sock_net(sk), NULL);
L
Linus Torvalds 已提交
1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
	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. */
1098
	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
L
Linus Torvalds 已提交
1099 1100 1101 1102
	if (!other)
		goto out;

	/* Latch state of peer */
1103
	unix_state_lock(other);
L
Linus Torvalds 已提交
1104 1105 1106

	/* Apparently VFS overslept socket death. Retry. */
	if (sock_flag(other, SOCK_DEAD)) {
1107
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1108 1109 1110 1111 1112 1113 1114
		sock_put(other);
		goto restart;
	}

	err = -ECONNREFUSED;
	if (other->sk_state != TCP_LISTEN)
		goto out_unlock;
1115 1116
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;
L
Linus Torvalds 已提交
1117

1118
	if (unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129
		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;
1130
	}
L
Linus Torvalds 已提交
1131 1132 1133

	/* Latch our state.

D
Daniel Baluta 已提交
1134
	   It is tricky place. We need to grab our state lock and cannot
L
Linus Torvalds 已提交
1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157
	   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;
	}

1158
	unix_state_lock_nested(sk);
L
Linus Torvalds 已提交
1159 1160

	if (sk->sk_state != st) {
1161 1162
		unix_state_unlock(sk);
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1163 1164 1165 1166
		sock_put(other);
		goto restart;
	}

1167
	err = security_unix_stream_connect(sk, other, newsk);
L
Linus Torvalds 已提交
1168
	if (err) {
1169
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1170 1171 1172 1173 1174 1175 1176 1177 1178
		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;
1179
	init_peercred(newsk);
L
Linus Torvalds 已提交
1180
	newu = unix_sk(newsk);
1181
	RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
L
Linus Torvalds 已提交
1182 1183 1184 1185 1186 1187 1188
	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
1189 1190 1191
	if (otheru->path.dentry) {
		path_get(&otheru->path);
		newu->path = otheru->path;
L
Linus Torvalds 已提交
1192 1193 1194
	}

	/* Set credentials */
1195
	copy_peercred(sk, other);
L
Linus Torvalds 已提交
1196 1197 1198

	sock->state	= SS_CONNECTED;
	sk->sk_state	= TCP_ESTABLISHED;
1199 1200 1201 1202
	sock_hold(newsk);

	smp_mb__after_atomic_inc();	/* sock_hold() does an atomic_inc() */
	unix_peer(sk)	= newsk;
L
Linus Torvalds 已提交
1203

1204
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1205 1206 1207 1208 1209

	/* 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);
1210
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1211 1212 1213 1214 1215 1216
	other->sk_data_ready(other, 0);
	sock_put(other);
	return 0;

out_unlock:
	if (other)
1217
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1218 1219

out:
1220
	kfree_skb(skb);
L
Linus Torvalds 已提交
1221 1222 1223 1224 1225 1226 1227 1228 1229
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
1230
	struct sock *ska = socka->sk, *skb = sockb->sk;
L
Linus Torvalds 已提交
1231 1232 1233 1234

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
1235 1236
	unix_peer(ska) = skb;
	unix_peer(skb) = ska;
1237 1238
	init_peercred(ska);
	init_peercred(skb);
L
Linus Torvalds 已提交
1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256

	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
1257
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
L
Linus Torvalds 已提交
1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280
		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 */
1281
	unix_state_lock(tsk);
L
Linus Torvalds 已提交
1282 1283
	newsock->state = SS_CONNECTED;
	sock_graft(tsk, newsock);
1284
	unix_state_unlock(tsk);
L
Linus Torvalds 已提交
1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295
	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;
1296
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
L
Linus Torvalds 已提交
1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310
	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);
1311
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321
	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);
	}
1322
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334
	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
1335
	for (i = scm->fp->count-1; i >= 0; i--)
L
Linus Torvalds 已提交
1336 1337 1338
		unix_notinflight(scm->fp->fp[i]);
}

1339
static void unix_destruct_scm(struct sk_buff *skb)
L
Linus Torvalds 已提交
1340 1341 1342
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
1343 1344 1345
	scm.pid  = UNIXCB(skb).pid;
	if (UNIXCB(skb).fp)
		unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
1346 1347 1348 1349 1350 1351 1352

	/* 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
1353 1354
#define MAX_RECURSION_LEVEL 4

1355
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
L
Linus Torvalds 已提交
1356 1357
{
	int i;
E
Eric Dumazet 已提交
1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
	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;
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381

	/*
	 * 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
1382 1383 1384 1385 1386
	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
1387 1388
}

1389
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1390 1391
{
	int err = 0;
1392

1393
	UNIXCB(skb).pid  = get_pid(scm->pid);
1394 1395
	UNIXCB(skb).uid = scm->creds.uid;
	UNIXCB(skb).gid = scm->creds.gid;
1396 1397 1398 1399 1400 1401 1402 1403
	UNIXCB(skb).fp = NULL;
	if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

	skb->destructor = unix_destruct_scm;
	return err;
}

1404 1405 1406 1407 1408 1409 1410 1411
/*
 * 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)
{
1412
	if (UNIXCB(skb).pid)
1413 1414
		return;
	if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1415 1416
	    !other->sk_socket ||
	    test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1417
		UNIXCB(skb).pid  = get_pid(task_tgid(current));
1418
		current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1419 1420 1421
	}
}

L
Linus Torvalds 已提交
1422 1423 1424 1425 1426 1427 1428 1429 1430
/*
 *	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;
1431
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1432
	struct unix_sock *u = unix_sk(sk);
1433
	struct sockaddr_un *sunaddr = msg->msg_name;
L
Linus Torvalds 已提交
1434 1435 1436
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
1437
	unsigned int hash;
1438
	struct sk_buff *skb;
L
Linus Torvalds 已提交
1439 1440
	long timeo;
	struct scm_cookie tmp_scm;
E
Eric Dumazet 已提交
1441
	int max_level;
1442
	int data_len = 0;
L
Linus Torvalds 已提交
1443 1444 1445

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1446
	wait_for_unix_gc();
1447
	err = scm_send(sock, msg, siocb->scm, false);
L
Linus Torvalds 已提交
1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
	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;
	}

1468 1469
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
	    && (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1470 1471 1472 1473 1474 1475
		goto out;

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

1476 1477 1478 1479 1480 1481 1482
	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);
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 1493 1494 1495
	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
1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506
	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;

1507
		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
L
Linus Torvalds 已提交
1508
					hash, &err);
1509
		if (other == NULL)
L
Linus Torvalds 已提交
1510 1511 1512
			goto out_free;
	}

A
Alban Crequy 已提交
1513 1514 1515 1516 1517 1518
	if (sk_filter(other, skb) < 0) {
		/* Toss the packet but do not return any error to the sender */
		err = len;
		goto out_free;
	}

1519
	unix_state_lock(other);
L
Linus Torvalds 已提交
1520 1521 1522 1523 1524 1525 1526 1527 1528
	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
		 */
1529
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1530 1531 1532
		sock_put(other);

		err = 0;
1533
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1534
		if (unix_peer(sk) == other) {
1535
			unix_peer(sk) = NULL;
1536
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1537 1538 1539 1540 1541

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
1542
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
		}

		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;
	}

1561
	if (unix_peer(other) != sk && unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575
		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;
	}

1576 1577
	if (sock_flag(other, SOCK_RCVTSTAMP))
		__net_timestamp(skb);
1578
	maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1579
	skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1580 1581
	if (max_level > unix_sk(other)->recursion_level)
		unix_sk(other)->recursion_level = max_level;
1582
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1583 1584
	other->sk_data_ready(other, len);
	sock_put(other);
1585
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1586 1587 1588
	return len;

out_unlock:
1589
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1590 1591 1592 1593 1594
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
1595
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1596 1597 1598
	return err;
}

1599

L
Linus Torvalds 已提交
1600 1601 1602 1603 1604 1605
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
1606
	int err, size;
1607
	struct sk_buff *skb;
1608
	int sent = 0;
L
Linus Torvalds 已提交
1609
	struct scm_cookie tmp_scm;
1610
	bool fds_sent = false;
E
Eric Dumazet 已提交
1611
	int max_level;
L
Linus Torvalds 已提交
1612 1613 1614

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1615
	wait_for_unix_gc();
1616
	err = scm_send(sock, msg, siocb->scm, false);
L
Linus Torvalds 已提交
1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628
	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;
1629
		other = unix_peer(sk);
L
Linus Torvalds 已提交
1630 1631 1632 1633 1634 1635 1636
		if (!other)
			goto out_err;
	}

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

E
Eric Dumazet 已提交
1637
	while (sent < len) {
L
Linus Torvalds 已提交
1638
		/*
1639 1640
		 *	Optimisation for the fact that under 0.01% of X
		 *	messages typically need breaking up.
L
Linus Torvalds 已提交
1641 1642
		 */

1643
		size = len-sent;
L
Linus Torvalds 已提交
1644 1645

		/* Keep two messages in the pipe so it schedules better */
1646 1647
		if (size > ((sk->sk_sndbuf >> 1) - 64))
			size = (sk->sk_sndbuf >> 1) - 64;
L
Linus Torvalds 已提交
1648 1649 1650

		if (size > SKB_MAX_ALLOC)
			size = SKB_MAX_ALLOC;
1651

L
Linus Torvalds 已提交
1652 1653 1654
		/*
		 *	Grab a buffer
		 */
1655

E
Eric Dumazet 已提交
1656 1657
		skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
					  &err);
L
Linus Torvalds 已提交
1658

1659
		if (skb == NULL)
L
Linus Torvalds 已提交
1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670
			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));

1671

1672 1673
		/* Only send the fds in the first buffer */
		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
E
Eric Dumazet 已提交
1674
		if (err < 0) {
1675
			kfree_skb(skb);
1676
			goto out_err;
1677
		}
E
Eric Dumazet 已提交
1678
		max_level = err + 1;
1679
		fds_sent = true;
L
Linus Torvalds 已提交
1680

E
Eric Dumazet 已提交
1681 1682
		err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
		if (err) {
L
Linus Torvalds 已提交
1683
			kfree_skb(skb);
1684
			goto out_err;
L
Linus Torvalds 已提交
1685 1686
		}

1687
		unix_state_lock(other);
L
Linus Torvalds 已提交
1688 1689 1690 1691 1692

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

1693
		maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1694
		skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1695 1696
		if (max_level > unix_sk(other)->recursion_level)
			unix_sk(other)->recursion_level = max_level;
1697
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1698
		other->sk_data_ready(other, size);
1699
		sent += size;
L
Linus Torvalds 已提交
1700 1701
	}

1702
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1703 1704 1705 1706 1707
	siocb->scm = NULL;

	return sent;

pipe_err_free:
1708
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1709 1710
	kfree_skb(skb);
pipe_err:
E
Eric Dumazet 已提交
1711 1712
	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
L
Linus Torvalds 已提交
1713 1714
	err = -EPIPE;
out_err:
1715
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1716 1717 1718 1719 1720 1721 1722 1723 1724
	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;
1725

L
Linus Torvalds 已提交
1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737
	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);
}
1738

1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750
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
1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772
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;
1773
	int peeked, skip;
L
Linus Torvalds 已提交
1774 1775 1776 1777 1778 1779 1780

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

	msg->msg_namelen = 0;

1781 1782 1783 1784 1785
	err = mutex_lock_interruptible(&u->readlock);
	if (err) {
		err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
		goto out;
	}
L
Linus Torvalds 已提交
1786

1787 1788 1789
	skip = sk_peek_offset(sk, flags);

	skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1790 1791 1792 1793 1794 1795 1796
	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
1797
		goto out_unlock;
1798
	}
L
Linus Torvalds 已提交
1799

E
Eric Dumazet 已提交
1800 1801
	wake_up_interruptible_sync_poll(&u->peer_wait,
					POLLOUT | POLLWRNORM | POLLWRBAND);
L
Linus Torvalds 已提交
1802 1803 1804 1805

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

1806 1807 1808
	if (size > skb->len - skip)
		size = skb->len - skip;
	else if (size < skb->len - skip)
L
Linus Torvalds 已提交
1809 1810
		msg->msg_flags |= MSG_TRUNC;

1811
	err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size);
L
Linus Torvalds 已提交
1812 1813 1814
	if (err)
		goto out_free;

1815 1816 1817
	if (sock_flag(sk, SOCK_RCVTSTAMP))
		__sock_recv_timestamp(msg, sk, skb);

L
Linus Torvalds 已提交
1818 1819 1820 1821
	if (!siocb->scm) {
		siocb->scm = &tmp_scm;
		memset(&tmp_scm, 0, sizeof(tmp_scm));
	}
1822
	scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
C
Catherine Zhang 已提交
1823
	unix_set_secdata(siocb->scm, skb);
L
Linus Torvalds 已提交
1824

E
Eric Dumazet 已提交
1825
	if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
1826 1827
		if (UNIXCB(skb).fp)
			unix_detach_fds(siocb->scm, skb);
1828 1829

		sk_peek_offset_bwd(sk, skb->len);
E
Eric Dumazet 已提交
1830
	} else {
L
Linus Torvalds 已提交
1831 1832 1833 1834 1835 1836
		/* 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)
1837 1838 1839 1840 1841

		   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
1842
		*/
1843 1844 1845

		sk_peek_offset_fwd(sk, size);

L
Linus Torvalds 已提交
1846 1847 1848
		if (UNIXCB(skb).fp)
			siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
	}
1849
	err = (flags & MSG_TRUNC) ? skb->len - skip : size;
L
Linus Torvalds 已提交
1850 1851 1852 1853

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

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

/*
1862
 *	Sleep until more data has arrived. But check for races..
L
Linus Torvalds 已提交
1863
 */
1864 1865
static long unix_stream_data_wait(struct sock *sk, long timeo,
				  struct sk_buff *last)
L
Linus Torvalds 已提交
1866 1867 1868
{
	DEFINE_WAIT(wait);

1869
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1870 1871

	for (;;) {
E
Eric Dumazet 已提交
1872
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
L
Linus Torvalds 已提交
1873

1874
		if (skb_peek_tail(&sk->sk_receive_queue) != last ||
L
Linus Torvalds 已提交
1875 1876 1877 1878 1879 1880 1881
		    sk->sk_err ||
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
		    signal_pending(current) ||
		    !timeo)
			break;

		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1882
		unix_state_unlock(sk);
1883
		timeo = freezable_schedule_timeout(timeo);
1884
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1885 1886 1887
		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
	}

E
Eric Dumazet 已提交
1888
	finish_wait(sk_sleep(sk), &wait);
1889
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
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
	int copied = 0;
	int check_creds = 0;
	int target;
	int err = 0;
	long timeo;
1907
	int skip;
L
Linus Torvalds 已提交
1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930

	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));
	}

1931 1932 1933 1934 1935
	err = mutex_lock_interruptible(&u->readlock);
	if (err) {
		err = sock_intr_errno(timeo);
		goto out;
	}
L
Linus Torvalds 已提交
1936

E
Eric Dumazet 已提交
1937
	do {
L
Linus Torvalds 已提交
1938
		int chunk;
1939
		struct sk_buff *skb, *last;
L
Linus Torvalds 已提交
1940

1941
		unix_state_lock(sk);
1942
		last = skb = skb_peek(&sk->sk_receive_queue);
1943
again:
E
Eric Dumazet 已提交
1944
		if (skb == NULL) {
E
Eric Dumazet 已提交
1945
			unix_sk(sk)->recursion_level = 0;
L
Linus Torvalds 已提交
1946
			if (copied >= target)
1947
				goto unlock;
L
Linus Torvalds 已提交
1948 1949 1950 1951

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
1952

E
Eric Dumazet 已提交
1953 1954
			err = sock_error(sk);
			if (err)
1955
				goto unlock;
L
Linus Torvalds 已提交
1956
			if (sk->sk_shutdown & RCV_SHUTDOWN)
1957 1958 1959
				goto unlock;

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

1965
			timeo = unix_stream_data_wait(sk, timeo, last);
L
Linus Torvalds 已提交
1966

1967 1968
			if (signal_pending(current)
			    ||  mutex_lock_interruptible(&u->readlock)) {
L
Linus Torvalds 已提交
1969 1970 1971
				err = sock_intr_errno(timeo);
				goto out;
			}
1972

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

1979 1980
		skip = sk_peek_offset(sk, flags);
		while (skip >= skb->len) {
1981
			skip -= skb->len;
1982
			last = skb;
1983
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
1984 1985
			if (!skb)
				goto again;
1986 1987
		}

1988
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1989 1990 1991

		if (check_creds) {
			/* Never glue messages from different writers */
1992
			if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
1993 1994
			    !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) ||
			    !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid))
L
Linus Torvalds 已提交
1995
				break;
1996
		} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
L
Linus Torvalds 已提交
1997
			/* Copy credentials */
1998
			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
L
Linus Torvalds 已提交
1999 2000 2001 2002
			check_creds = 1;
		}

		/* Copy address just once */
E
Eric Dumazet 已提交
2003
		if (sunaddr) {
L
Linus Torvalds 已提交
2004 2005 2006 2007
			unix_copy_addr(msg, skb->sk);
			sunaddr = NULL;
		}

2008 2009
		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
2010 2011 2012 2013 2014 2015 2016 2017
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

		/* Mark read part of skb as used */
E
Eric Dumazet 已提交
2018
		if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
2019 2020
			skb_pull(skb, chunk);

2021 2022
			sk_peek_offset_bwd(sk, chunk);

L
Linus Torvalds 已提交
2023 2024 2025
			if (UNIXCB(skb).fp)
				unix_detach_fds(siocb->scm, skb);

2026
			if (skb->len)
L
Linus Torvalds 已提交
2027 2028
				break;

2029
			skb_unlink(skb, &sk->sk_receive_queue);
2030
			consume_skb(skb);
L
Linus Torvalds 已提交
2031 2032 2033

			if (siocb->scm->fp)
				break;
E
Eric Dumazet 已提交
2034
		} else {
L
Linus Torvalds 已提交
2035 2036 2037 2038 2039
			/* It is questionable, see note in unix_dgram_recvmsg.
			 */
			if (UNIXCB(skb).fp)
				siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);

2040 2041
			sk_peek_offset_fwd(sk, chunk);

L
Linus Torvalds 已提交
2042 2043 2044 2045
			break;
		}
	} while (size);

I
Ingo Molnar 已提交
2046
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
2047 2048 2049 2050 2051 2052 2053 2054 2055 2056
	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;

2057 2058 2059 2060 2061 2062 2063 2064
	if (mode < SHUT_RD || mode > SHUT_RDWR)
		return -EINVAL;
	/* This maps:
	 * SHUT_RD   (0) -> RCV_SHUTDOWN  (1)
	 * SHUT_WR   (1) -> SEND_SHUTDOWN (2)
	 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
	 */
	++mode;
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

	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
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2199
		mask |= POLLERR |
2200
			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2201

2202
	if (sk->sk_shutdown & RCV_SHUTDOWN)
2203
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2204 2205 2206 2207
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
2208
	if (!skb_queue_empty(&sk->sk_receive_queue))
2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
		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
2220
	/* No write status requested, avoid expensive OUT tests. */
2221
	if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
E
Eric Dumazet 已提交
2222 2223
		return mask;

2224
	writable = unix_writable(sk);
2225 2226 2227 2228 2229 2230
	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;
2231
		}
2232
		sock_put(other);
2233 2234 2235
	}

	if (writable)
2236 2237 2238 2239 2240 2241
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	return mask;
}
L
Linus Torvalds 已提交
2242 2243

#ifdef CONFIG_PROC_FS
2244

E
Eric Dumazet 已提交
2245 2246 2247 2248 2249
#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)

#define get_bucket(x) ((x) >> BUCKET_SPACE)
#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2250

E
Eric Dumazet 已提交
2251
static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
L
Linus Torvalds 已提交
2252
{
E
Eric Dumazet 已提交
2253 2254 2255 2256
	unsigned long offset = get_offset(*pos);
	unsigned long bucket = get_bucket(*pos);
	struct sock *sk;
	unsigned long count = 0;
L
Linus Torvalds 已提交
2257

E
Eric Dumazet 已提交
2258 2259
	for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
		if (sock_net(sk) != seq_file_net(seq))
2260
			continue;
E
Eric Dumazet 已提交
2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279
		if (++count == offset)
			break;
	}

	return sk;
}

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

	while (sk > (struct sock *)SEQ_START_TOKEN) {
		sk = sk_next(sk);
		if (!sk)
			goto next_bucket;
		if (sock_net(sk) == seq_file_net(seq))
			return sk;
L
Linus Torvalds 已提交
2280
	}
E
Eric Dumazet 已提交
2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291

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

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

L
Linus Torvalds 已提交
2292 2293 2294 2295
	return NULL;
}

static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2296
	__acquires(unix_table_lock)
L
Linus Torvalds 已提交
2297
{
2298
	spin_lock(&unix_table_lock);
E
Eric Dumazet 已提交
2299 2300 2301 2302 2303 2304 2305 2306

	if (!*pos)
		return SEQ_START_TOKEN;

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

	return unix_next_socket(seq, NULL, pos);
L
Linus Torvalds 已提交
2307 2308 2309 2310 2311
}

static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;
E
Eric Dumazet 已提交
2312
	return unix_next_socket(seq, v, pos);
L
Linus Torvalds 已提交
2313 2314 2315
}

static void unix_seq_stop(struct seq_file *seq, void *v)
2316
	__releases(unix_table_lock)
L
Linus Torvalds 已提交
2317
{
2318
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
2319 2320 2321 2322
}

static int unix_seq_show(struct seq_file *seq, void *v)
{
2323

J
Joe Perches 已提交
2324
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2325 2326 2327 2328 2329
		seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
			 "Inode Path\n");
	else {
		struct sock *s = v;
		struct unix_sock *u = unix_sk(s);
2330
		unix_state_lock(s);
L
Linus Torvalds 已提交
2331

D
Dan Rosenberg 已提交
2332
		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
L
Linus Torvalds 已提交
2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357
			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]);
		}
2358
		unix_state_unlock(s);
L
Linus Torvalds 已提交
2359 2360 2361 2362 2363 2364
		seq_putc(seq, '\n');
	}

	return 0;
}

2365
static const struct seq_operations unix_seq_ops = {
L
Linus Torvalds 已提交
2366 2367 2368 2369 2370 2371 2372 2373
	.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)
{
2374
	return seq_open_net(inode, file, &unix_seq_ops,
E
Eric Dumazet 已提交
2375
			    sizeof(struct seq_net_private));
L
Linus Torvalds 已提交
2376 2377
}

2378
static const struct file_operations unix_seq_fops = {
L
Linus Torvalds 已提交
2379 2380 2381 2382
	.owner		= THIS_MODULE,
	.open		= unix_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2383
	.release	= seq_release_net,
L
Linus Torvalds 已提交
2384 2385 2386 2387
};

#endif

2388
static const struct net_proto_family unix_family_ops = {
L
Linus Torvalds 已提交
2389 2390 2391 2392 2393
	.family = PF_UNIX,
	.create = unix_create,
	.owner	= THIS_MODULE,
};

2394

2395
static int __net_init unix_net_init(struct net *net)
2396 2397 2398
{
	int error = -ENOMEM;

2399
	net->unx.sysctl_max_dgram_qlen = 10;
2400 2401
	if (unix_sysctl_register(net))
		goto out;
2402

2403
#ifdef CONFIG_PROC_FS
2404
	if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2405
		unix_sysctl_unregister(net);
2406
		goto out;
2407
	}
2408 2409 2410
#endif
	error = 0;
out:
2411
	return error;
2412 2413
}

2414
static void __net_exit unix_net_exit(struct net *net)
2415
{
2416
	unix_sysctl_unregister(net);
2417
	remove_proc_entry("unix", net->proc_net);
2418 2419 2420 2421 2422 2423 2424
}

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

L
Linus Torvalds 已提交
2425 2426 2427 2428
static int __init af_unix_init(void)
{
	int rc = -1;

2429
	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
L
Linus Torvalds 已提交
2430 2431

	rc = proto_register(&unix_proto, 1);
2432 2433
	if (rc != 0) {
		printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2434
		       __func__);
L
Linus Torvalds 已提交
2435 2436 2437 2438
		goto out;
	}

	sock_register(&unix_family_ops);
2439
	register_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2440 2441 2442 2443 2444 2445 2446 2447
out:
	return rc;
}

static void __exit af_unix_exit(void)
{
	sock_unregister(PF_UNIX);
	proto_unregister(&unix_proto);
2448
	unregister_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2449 2450
}

2451 2452 2453 2454 2455
/* 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
2456 2457 2458 2459
module_exit(af_unix_exit);

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