sock(ADMP)

sock -- socket interface driver

Description

The socket driver is used to provide socket emulation to applications. Sockets provide an alternative to TLI as an entry point into transport providers, such as tcp(ADMP). The socket driver is a character device that acts as an alternate stream head, augmenting the functions of the standard stream head. It also provides support for miscellaneous functions such as select(S).

The behavior of sockets in handling asynchronous events and errors was changed in UnixWare^® 7 release 7.1.1. Compatibity with behavior in earlier releases of UnixWare 7 may be obtained using the SI_U7COMPAT ioctl(S) command on the socket file descriptor:

   #include <sys/sockmod.h>
   ...
   int err, fd, x;
   ...
   /* Create a socket */
   fd = socket(domain, type, protocol);
   ...
   /* Select new behavior */
   x = 0;
   err = ioctl(fd, SI_UW7COMPAT, &x);
   ...
   /* Select old behavior */
   x = 1;
   err = ioctl(fd, SI_UW7COMPAT, &x);

In the above examples, the value passed in by the argument x controls the behavior of the socket as follows:

0

Select new behavior:

For read(S), recv(SSC), recvmsg(SSC) and recvfrom(SSC), an asynchronous error causes the function to return with an error without reading any data.
For write(S), send(SSC), sendmsg(SSC) and sendto(SSC), an asynchronous error causes the function to return with an error without writing any data.
For poll(S), an asynchronous error causes POLLERR to be set in the revent member of the file descriptor's pollfd structure.
For select(S), an asynchronous error causes an exception to be set in the exceptfds fd_set that corresponds to the file descriptor.

1

Select old behavior:

connect(SSC) blocks all signals except SIGHUP, SIGINT, SIGQUIT, and SIGTERM.
connect(SSC) always returns EINPROGRESS when first called to establish an asynchronous connection.
If data received by a connectionless socket is not for the connected address, getsockopt(SSC) can retrieve EINVAL set for SO_ERROR. Other operations may set the asynchronous error returned by SO_ERROR.

Default socket behavior is controlled by the value of the inconfig(ADMN) ss_uw7_compat parameter.

Files

/dev/socksys: device interface to the socket driver

References

Intro(ADMP), ifconfig(ADMN), inconfig(ADMN), inet(ADMP), slattach(ADMN) socket(ADMP), sockio(ADMP), unix(ADMP), usock(ADMP),