The Linux Programming Interface

57SOCKETS: UNIX DOMAIN

This chapter looks at the use of UNIX domain sockets, which allow communication between processes on the same host system. We discuss the use of both stream and datagram sockets in the UNIX domain. We also describe the use of file permissions to control access to UNIX domain sockets, the use of socketpair() to create a pair of connected UNIX domain sockets, and the Linux abstract socket namespace.

57.1 UNIX Domain Socket Addresses: struct sockaddr_un

In the UNIX domain, a socket address takes the form of a pathname, and the domain-specific socket address structure is defined as follows:

struct sockaddr_un {    sa_family_t sun_family;        /* Always AF_UNIX */    char sun_path[108];            /* Null-terminated socket ...