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af_unix.c
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af_unix.c
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/*
* NET4: Implementation of BSD Unix domain sockets.
*
* Authors: Alan Cox, <[email protected]>
*
* 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.
*
* Version: $Id: af_unix.c,v 1.133 2002/02/08 03:57:19 davem Exp $
*
* 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/config.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>
#include <net/sock.h>
#include <net/tcp_states.h>
#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/smp_lock.h>
#include <linux/rtnetlink.h>
#include <linux/mount.h>
#include <net/checksum.h>
#include <linux/security.h>
int sysctl_unix_max_dgram_qlen = 10;
struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
DEFINE_RWLOCK(unix_table_lock);
static atomic_t unix_nr_socks = ATOMIC_INIT(0);
#define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
/*
* SMP locking strategy:
* hash table is protected with rwlock unix_table_lock
* each socket state is protected by separate rwlock.
*/
static inline unsigned unix_hash_fold(unsigned hash)
{
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)
{
return (unix_peer(osk) == NULL || unix_our_peer(sk, osk));
}
static struct sock *unix_peer_get(struct sock *s)
{
struct sock *peer;
unix_state_rlock(s);
peer = unix_peer(s);
if (peer)
sock_hold(peer);
unix_state_runlock(s);
return peer;
}
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.
*/
static int unix_mkname(struct sockaddr_un * sunaddr, int len, unsigned *hashp)
{
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.
* sun_path[108] doesnt as such exist. However in kernel space
* we are guaranteed that it is a valid memory location in our
* kernel address buffer.
*/
((char *)sunaddr)[len]=0;
len = strlen(sunaddr->sun_path)+1+sizeof(short);
return len;
}
*hashp = unix_hash_fold(csum_partial((char*)sunaddr, len, 0));
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)
{
BUG_TRAP(sk_unhashed(sk));
sk_add_node(sk, list);
}
static inline void unix_remove_socket(struct sock *sk)
{
write_lock(&unix_table_lock);
__unix_remove_socket(sk);
write_unlock(&unix_table_lock);
}
static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
{
write_lock(&unix_table_lock);
__unix_insert_socket(list, sk);
write_unlock(&unix_table_lock);
}
static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname,
int len, int type, unsigned hash)
{
struct sock *s;
struct hlist_node *node;
sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
struct unix_sock *u = unix_sk(s);
if (u->addr->len == len &&
!memcmp(u->addr->name, sunname, len))
goto found;
}
s = NULL;
found:
return s;
}
static inline struct sock *unix_find_socket_byname(struct sockaddr_un *sunname,
int len, int type,
unsigned hash)
{
struct sock *s;
read_lock(&unix_table_lock);
s = __unix_find_socket_byname(sunname, len, type, hash);
if (s)
sock_hold(s);
read_unlock(&unix_table_lock);
return s;
}
static struct sock *unix_find_socket_byinode(struct inode *i)
{
struct sock *s;
struct hlist_node *node;
read_lock(&unix_table_lock);
sk_for_each(s, node,
&unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
struct dentry *dentry = unix_sk(s)->dentry;
if(dentry && dentry->d_inode == i)
{
sock_hold(s);
goto found;
}
}
s = NULL;
found:
read_unlock(&unix_table_lock);
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)
{
read_lock(&sk->sk_callback_lock);
if (unix_writable(sk)) {
if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
wake_up_interruptible(sk->sk_sleep);
sk_wake_async(sk, 2, POLL_OUT);
}
read_unlock(&sk->sk_callback_lock);
}
/* 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)
{
if (!skb_queue_empty(&sk->sk_receive_queue)) {
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);
BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
BUG_TRAP(sk_unhashed(sk));
BUG_TRAP(!sk->sk_socket);
if (!sock_flag(sk, SOCK_DEAD)) {
printk("Attempt to release alive unix socket: %p\n", sk);
return;
}
if (u->addr)
unix_release_addr(u->addr);
atomic_dec(&unix_nr_socks);
#ifdef UNIX_REFCNT_DEBUG
printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk, atomic_read(&unix_nr_socks));
#endif
}
static int unix_release_sock (struct sock *sk, int embrion)
{
struct unix_sock *u = unix_sk(sk);
struct dentry *dentry;
struct vfsmount *mnt;
struct sock *skpair;
struct sk_buff *skb;
int state;
unix_remove_socket(sk);
/* Clear state */
unix_state_wlock(sk);
sock_orphan(sk);
sk->sk_shutdown = SHUTDOWN_MASK;
dentry = u->dentry;
u->dentry = NULL;
mnt = u->mnt;
u->mnt = NULL;
state = sk->sk_state;
sk->sk_state = TCP_CLOSE;
unix_state_wunlock(sk);
wake_up_interruptible_all(&u->peer_wait);
skpair=unix_peer(sk);
if (skpair!=NULL) {
if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
unix_state_wlock(skpair);
/* No more writes */
skpair->sk_shutdown = SHUTDOWN_MASK;
if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
skpair->sk_err = ECONNRESET;
unix_state_wunlock(skpair);
skpair->sk_state_change(skpair);
read_lock(&skpair->sk_callback_lock);
sk_wake_async(skpair,1,POLL_HUP);
read_unlock(&skpair->sk_callback_lock);
}
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) {
if (state==TCP_LISTEN)
unix_release_sock(skb->sk, 1);
/* passed fds are erased in the kfree_skb hook */
kfree_skb(skb);
}
if (dentry) {
dput(dentry);
mntput(mnt);
}
sock_put(sk);
/* ---- Socket is dead now and most probably destroyed ---- */
/*
* Fixme: BSD difference: In BSD all sockets connected to use get
* ECONNRESET and we die on the spot. In Linux we behave
* like files and pipes do and wait for the last
* dereference.
*
* Can't we simply set sock->err?
*
* What the above comment does talk about? --ANK(980817)
*/
if (atomic_read(&unix_tot_inflight))
unix_gc(); /* Garbage collect fds */
return 0;
}
static int unix_listen(struct socket *sock, int backlog)
{
int err;
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk);
err = -EOPNOTSUPP;
if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET)
goto out; /* Only stream/seqpacket sockets accept */
err = -EINVAL;
if (!u->addr)
goto out; /* No listens on an unbound socket */
unix_state_wlock(sk);
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 */
sk->sk_peercred.pid = current->tgid;
sk->sk_peercred.uid = current->euid;
sk->sk_peercred.gid = current->egid;
err = 0;
out_unlock:
unix_state_wunlock(sk);
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 *);
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);
static struct proto_ops unix_stream_ops = {
.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,
};
static struct proto_ops unix_dgram_ops = {
.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,
.poll = datagram_poll,
.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,
};
static struct proto_ops unix_seqpacket_ops = {
.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 = datagram_poll,
.ioctl = unix_ioctl,
.listen = unix_listen,
.shutdown = unix_shutdown,
.setsockopt = sock_no_setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = unix_seqpacket_sendmsg,
.recvmsg = unix_dgram_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
static struct proto unix_proto = {
.name = "UNIX",
.owner = THIS_MODULE,
.obj_size = sizeof(struct unix_sock),
};
static struct sock * unix_create1(struct socket *sock)
{
struct sock *sk = NULL;
struct unix_sock *u;
if (atomic_read(&unix_nr_socks) >= 2*files_stat.max_files)
goto out;
sk = sk_alloc(PF_UNIX, GFP_KERNEL, &unix_proto, 1);
if (!sk)
goto out;
atomic_inc(&unix_nr_socks);
sock_init_data(sock,sk);
sk->sk_write_space = unix_write_space;
sk->sk_max_ack_backlog = sysctl_unix_max_dgram_qlen;
sk->sk_destruct = unix_sock_destructor;
u = unix_sk(sk);
u->dentry = NULL;
u->mnt = NULL;
rwlock_init(&u->lock);
atomic_set(&u->inflight, sock ? 0 : -1);
init_MUTEX(&u->readsem); /* single task reading lock */
init_waitqueue_head(&u->peer_wait);
unix_insert_socket(unix_sockets_unbound, sk);
out:
return sk;
}
static int unix_create(struct socket *sock, int protocol)
{
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:
sock->type=SOCK_DGRAM;
case SOCK_DGRAM:
sock->ops = &unix_dgram_ops;
break;
case SOCK_SEQPACKET:
sock->ops = &unix_seqpacket_ops;
break;
default:
return -ESOCKTNOSUPPORT;
}
return unix_create1(sock) ? 0 : -ENOMEM;
}
static int unix_release(struct socket *sock)
{
struct sock *sk = sock->sk;
if (!sk)
return 0;
sock->sk = NULL;
return unix_release_sock (sk, 0);
}
static int unix_autobind(struct socket *sock)
{
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk);
static u32 ordernum = 1;
struct unix_address * addr;
int err;
down(&u->readsem);
err = 0;
if (u->addr)
goto out;
err = -ENOMEM;
addr = kmalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
if (!addr)
goto out;
memset(addr, 0, sizeof(*addr) + sizeof(short) + 16);
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);
addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0));
write_lock(&unix_table_lock);
ordernum = (ordernum+1)&0xFFFFF;
if (__unix_find_socket_byname(addr->name, addr->len, sock->type,
addr->hash)) {
write_unlock(&unix_table_lock);
/* Sanity yield. It is unusual case, but yet... */
if (!(ordernum&0xFF))
yield();
goto retry;
}
addr->hash ^= sk->sk_type;
__unix_remove_socket(sk);
u->addr = addr;
__unix_insert_socket(&unix_socket_table[addr->hash], sk);
write_unlock(&unix_table_lock);
err = 0;
out: up(&u->readsem);
return err;
}
static struct sock *unix_find_other(struct sockaddr_un *sunname, int len,
int type, unsigned hash, int *error)
{
struct sock *u;
struct nameidata nd;
int err = 0;
if (sunname->sun_path[0]) {
err = path_lookup(sunname->sun_path, LOOKUP_FOLLOW, &nd);
if (err)
goto fail;
err = permission(nd.dentry->d_inode,MAY_WRITE, &nd);
if (err)
goto put_fail;
err = -ECONNREFUSED;
if (!S_ISSOCK(nd.dentry->d_inode->i_mode))
goto put_fail;
u=unix_find_socket_byinode(nd.dentry->d_inode);
if (!u)
goto put_fail;
if (u->sk_type == type)
touch_atime(nd.mnt, nd.dentry);
path_release(&nd);
err=-EPROTOTYPE;
if (u->sk_type != type) {
sock_put(u);
goto fail;
}
} else {
err = -ECONNREFUSED;
u=unix_find_socket_byname(sunname, len, type, hash);
if (u) {
struct dentry *dentry;
dentry = unix_sk(u)->dentry;
if (dentry)
touch_atime(unix_sk(u)->mnt, dentry);
} else
goto fail;
}
return u;
put_fail:
path_release(&nd);
fail:
*error=err;
return NULL;
}
static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk);
struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
struct dentry * dentry = NULL;
struct nameidata nd;
int err;
unsigned hash;
struct unix_address *addr;
struct hlist_head *list;
err = -EINVAL;
if (sunaddr->sun_family != AF_UNIX)
goto out;
if (addr_len==sizeof(short)) {
err = unix_autobind(sock);
goto out;
}
err = unix_mkname(sunaddr, addr_len, &hash);
if (err < 0)
goto out;
addr_len = err;
down(&u->readsem);
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);
if (sunaddr->sun_path[0]) {
unsigned int mode;
err = 0;
/*
* Get the parent directory, calculate the hash for last
* component.
*/
err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
if (err)
goto out_mknod_parent;
dentry = lookup_create(&nd, 0);
err = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_mknod_unlock;
/*
* All right, let's create it.
*/
mode = S_IFSOCK |
(SOCK_INODE(sock)->i_mode & ~current->fs->umask);
err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0);
if (err)
goto out_mknod_dput;
up(&nd.dentry->d_inode->i_sem);
dput(nd.dentry);
nd.dentry = dentry;
addr->hash = UNIX_HASH_SIZE;
}
write_lock(&unix_table_lock);
if (!sunaddr->sun_path[0]) {
err = -EADDRINUSE;
if (__unix_find_socket_byname(sunaddr, addr_len,
sk->sk_type, hash)) {
unix_release_addr(addr);
goto out_unlock;
}
list = &unix_socket_table[addr->hash];
} else {
list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
u->dentry = nd.dentry;
u->mnt = nd.mnt;
}
err = 0;
__unix_remove_socket(sk);
u->addr = addr;
__unix_insert_socket(list, sk);
out_unlock:
write_unlock(&unix_table_lock);
out_up:
up(&u->readsem);
out:
return err;
out_mknod_dput:
dput(dentry);
out_mknod_unlock:
up(&nd.dentry->d_inode->i_sem);
path_release(&nd);
out_mknod_parent:
if (err==-EEXIST)
err=-EADDRINUSE;
unix_release_addr(addr);
goto out_up;
}
static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
int alen, int flags)
{
struct sock *sk = sock->sk;
struct sockaddr_un *sunaddr=(struct sockaddr_un*)addr;
struct sock *other;
unsigned hash;
int err;
if (addr->sa_family != AF_UNSPEC) {
err = unix_mkname(sunaddr, alen, &hash);
if (err < 0)
goto out;
alen = err;
if (test_bit(SOCK_PASSCRED, &sock->flags) &&
!unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
goto out;
other=unix_find_other(sunaddr, alen, sock->type, hash, &err);
if (!other)
goto out;
unix_state_wlock(sk);
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;
unix_state_wlock(sk);
}
/*
* If it was connected, reconnect.
*/
if (unix_peer(sk)) {
struct sock *old_peer = unix_peer(sk);
unix_peer(sk)=other;
unix_state_wunlock(sk);
if (other != old_peer)
unix_dgram_disconnected(sk, old_peer);
sock_put(old_peer);
} else {
unix_peer(sk)=other;
unix_state_wunlock(sk);
}
return 0;
out_unlock:
unix_state_wunlock(sk);
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) &&
(skb_queue_len(&other->sk_receive_queue) >
other->sk_max_ack_backlog);
unix_state_runlock(other);
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)
{
struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk), *newu, *otheru;
struct sock *newsk = NULL;
struct sock *other = NULL;
struct sk_buff *skb = NULL;
unsigned hash;
int st;
int err;
long timeo;
err = unix_mkname(sunaddr, addr_len, &hash);
if (err < 0)
goto out;
addr_len = err;
if (test_bit(SOCK_PASSCRED, &sock->flags)
&& !u->addr && (err = unix_autobind(sock)) != 0)
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 */
newsk = unix_create1(NULL);
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. */
other = unix_find_other(sunaddr, addr_len, sk->sk_type, hash, &err);
if (!other)
goto out;
/* Latch state of peer */
unix_state_rlock(other);
/* Apparently VFS overslept socket death. Retry. */
if (sock_flag(other, SOCK_DEAD)) {
unix_state_runlock(other);
sock_put(other);
goto restart;
}
err = -ECONNREFUSED;
if (other->sk_state != TCP_LISTEN)
goto out_unlock;
if (skb_queue_len(&other->sk_receive_queue) >
other->sk_max_ack_backlog) {
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;
}
/* Latch our state.