af_unix.c

Linux Kernel 2.6.9 for OMAP1710

	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;
	}

	unix_state_wlock(sk);

	if (sk->sk_state != st) {
		unix_state_wunlock(sk);
		unix_state_runlock(other);
		sock_put(other);
		goto restart;
	}

	err = security_unix_stream_connect(sock, other->sk_socket, newsk);
	if (err) {
		unix_state_wunlock(sk);
		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;
	newsk->sk_peercred.pid	= current->tgid;
	newsk->sk_peercred.uid	= current->euid;
	newsk->sk_peercred.gid	= current->egid;
	newu = unix_sk(newsk);
	newsk->sk_sleep		= &newu->peer_wait;
	otheru = unix_sk(other);

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

	/* Set credentials */
	sk->sk_peercred = other->sk_peercred;

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

	unix_state_wunlock(sk);

	/* take ten and and send info to listening sock */
	spin_lock(&other->sk_receive_queue.lock);
	__skb_queue_tail(&other->sk_receive_queue, skb);
	/* Undo artificially decreased inflight after embrion
	 * is installed to listening socket. */
	atomic_inc(&newu->inflight);
	spin_unlock(&other->sk_receive_queue.lock);
	unix_state_runlock(other);
	other->sk_data_ready(other, 0);
	sock_put(other);
	return 0;

out_unlock:
	if (other)
		unix_state_runlock(other);

out:
	if (skb)
		kfree_skb(skb);
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
	struct sock *ska=socka->sk, *skb = sockb->sk;

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
	unix_peer(ska)=skb;
	unix_peer(skb)=ska;
	ska->sk_peercred.pid = skb->sk_peercred.pid = current->tgid;
	ska->sk_peercred.uid = skb->sk_peercred.uid = current->euid;
	ska->sk_peercred.gid = skb->sk_peercred.gid = current->egid;

	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;
	if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET)
		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 */
	unix_state_wlock(tsk);
	newsock->state = SS_CONNECTED;
	sock_graft(tsk, newsock);
	unix_state_wunlock(tsk);
	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;
	struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
	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);
	unix_state_rlock(sk);
	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);
	}
	unix_state_runlock(sk);
	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;
	skb->destructor = sock_wfree;
	UNIXCB(skb).fp = NULL;

	for (i=scm->fp->count-1; i>=0; i--)
		unix_notinflight(scm->fp->fp[i]);
}

static void unix_destruct_fds(struct sk_buff *skb)
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
	unix_detach_fds(&scm, skb);

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

static void unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
{
	int i;
	for (i=scm->fp->count-1; i>=0; i--)
		unix_inflight(scm->fp->fp[i]);
	UNIXCB(skb).fp = scm->fp;
	skb->destructor = unix_destruct_fds;
	scm->fp = NULL;
}

/*
 *	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;
	struct unix_sock *u = unix_sk(sk);
	struct sockaddr_un *sunaddr=msg->msg_name;
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
	unsigned hash;
	struct sk_buff *skb;
	long timeo;
	struct scm_cookie tmp_scm;

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
	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;
	}

	if (sock->passcred && !u->addr && (err = unix_autobind(sock)) != 0)
		goto out;

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

	skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
	if (skb==NULL)
		goto out;

	memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
	if (siocb->scm->fp)
		unix_attach_fds(siocb->scm, skb);

	skb->h.raw = skb->data;
	err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
	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;

		other = unix_find_other(sunaddr, namelen, sk->sk_type,
					hash, &err);
		if (other==NULL)
			goto out_free;
	}

	unix_state_rlock(other);
	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
		 */
		unix_state_runlock(other);
		sock_put(other);

		err = 0;
		unix_state_wlock(sk);
		if (unix_peer(sk) == other) {
			unix_peer(sk)=NULL;
			unix_state_wunlock(sk);

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
			unix_state_wunlock(sk);
		}

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

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

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

	if (unix_peer(other) != sk &&
	    (skb_queue_len(&other->sk_receive_queue) >
	     other->sk_max_ack_backlog)) {
		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;
	}

	skb_queue_tail(&other->sk_receive_queue, skb);
	unix_state_runlock(other);
	other->sk_data_ready(other, len);
	sock_put(other);
	scm_destroy(siocb->scm);
	return len;

out_unlock:
	unix_state_runlock(other);
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
	scm_destroy(siocb->scm);
	return err;
}

		
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;
	struct sockaddr_un *sunaddr=msg->msg_name;
	int err,size;
	struct sk_buff *skb;
	int sent=0;
	struct scm_cookie tmp_scm;

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
	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 {
		sunaddr = NULL;
		err = -ENOTCONN;
		other = unix_peer_get(sk);
		if (!other)
			goto out_err;
	}

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

	while(sent < len)
	{
		/*
		 *	Optimisation for the fact that under 0.01% of X messages typically
		 *	need breaking up.
		 */

		size=len-sent;

		/* Keep two messages in the pipe so it schedules better */
		if (size > sk->sk_sndbuf / 2 - 64)
			size = sk->sk_sndbuf / 2 - 64;

		if (size > SKB_MAX_ALLOC)
			size = SKB_MAX_ALLOC;
			
		/*
		 *	Grab a buffer
		 */
		 
		skb=sock_alloc_send_skb(sk,size,msg->msg_flags&MSG_DONTWAIT, &err);

		if (skb==NULL)
			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));

		memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
		if (siocb->scm->fp)
			unix_attach_fds(siocb->scm, skb);

		if ((err = memcpy_fromiovec(skb_put(skb,size), msg->msg_iov, size)) != 0) {
			kfree_skb(skb);
			goto out_err;
		}

		unix_state_rlock(other);

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

		skb_queue_tail(&other->sk_receive_queue, skb);
		unix_state_runlock(other);
		other->sk_data_ready(other, size);
		sent+=size;
	}
	sock_put(other);

	scm_destroy(siocb->scm);
	siocb->scm = NULL;

	return sent;

pipe_err_free:
	unix_state_runlock(other);
	kfree_skb(skb);
pipe_err:
	if (sent==0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE,current,0);
	err = -EPIPE;
out_err:
        if (other)
		sock_put(other);
	scm_destroy(siocb->scm);
	siocb->scm = NULL;
	return sent ? : err;
}

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;

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

	msg->msg_namelen = 0;