Hi, I am not absolutely sure whether this actually is a bug (as in: I've got no clue what the standards say or what other implementations do), but at least I was pretty surprised when I noticed that a recv() on a non-blocking unix domain socket of type SOCK_SEQPACKET (which is connection oriented, after all) where the remote end has closed the connection returned -1 (EAGAIN) rather than 0 to indicate end of file.
This is a test case: | #include <sys/types.h> | #include <unistd.h> | #include <sys/socket.h> | #include <sys/un.h> | #include <fcntl.h> | #include <string.h> | #include <stdlib.h> | | int main(){ | int sock; | struct sockaddr_un addr; | char buf[4096]; | int pfds[2]; | | pipe(pfds); | sock=socket(PF_UNIX,SOCK_SEQPACKET,0); | addr.sun_family=AF_UNIX; | strcpy(addr.sun_path,"/tmp/foobar_testsock"); | bind(sock,(struct sockaddr *)&addr,sizeof(addr)); | listen(sock,1); | if(fork()){ | close(sock); | sock=socket(PF_UNIX,SOCK_SEQPACKET,0); | connect(sock,(struct sockaddr *)&addr,sizeof(addr)); | fcntl(sock,F_SETFL,fcntl(sock,F_GETFL)|O_NONBLOCK); | close(pfds[1]); | read(pfds[0],buf,sizeof(buf)); | recv(sock,buf,sizeof(buf),0); // <-- this one | }else accept(sock,NULL,NULL); | exit(0); | } If you try it, make sure /tmp/foobar_testsock doesn't exist. The marked recv() returns -1 (EAGAIN) on 2.6.23.9. Below you find a patch that fixes that. Florian --------------------------------------------------------------------------- Signed-off-by: Florian Zumbiehl <[EMAIL PROTECTED]> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index a05c342..fa0aec5 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1632,8 +1632,13 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, mutex_lock(&u->readlock); skb = skb_recv_datagram(sk, flags, noblock, &err); - if (!skb) + if (!skb) { + unix_state_lock(sk); + if (sk->sk_type==SOCK_SEQPACKET && err==-EAGAIN && (sk->sk_shutdown&RCV_SHUTDOWN)) + err=0; /* signal EOF on disconnected non-blocking SEQPACKET socket */ + unix_state_unlock(sk); goto out_unlock; + } wake_up_interruptible(&u->peer_wait); - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html