1/*++
2/* NAME
3/*	unix_listen 3
4/* SUMMARY
5/*	start UNIX-domain listener
6/* SYNOPSIS
7/*	#include <listen.h>
8/*
9/*	int	unix_listen(addr, backlog, block_mode)
10/*	const char *addr;
11/*	int	backlog;
12/*	int	block_mode;
13/*
14/*	int	unix_accept(fd)
15/*	int	fd;
16/* DESCRIPTION
17/*	The \fBunix_listen\fR() routine starts a listener in the UNIX domain
18/*	on the specified address, with the specified backlog, and returns
19/*	the resulting file descriptor.
20/*
21/*	unix_accept() accepts a connection and sanitizes error results.
22/*
23/*	Arguments:
24/* .IP addr
25/*	Null-terminated string with connection destination.
26/* .IP backlog
27/*	This argument is passed on to the \fIlisten(2)\fR routine.
28/* .IP block_mode
29/*	Either NON_BLOCKING for a non-blocking socket, or BLOCKING for
30/*	blocking mode.
31/* .IP fd
32/*	File descriptor returned by unix_listen().
33/* DIAGNOSTICS
34/*	Fatal errors: unix_listen() aborts upon any system call failure.
35/*	unix_accept() leaves all error handling up to the caller.
36/* LICENSE
37/* .ad
38/* .fi
39/*	The Secure Mailer license must be distributed with this software.
40/* AUTHOR(S)
41/*	Wietse Venema
42/*	IBM T.J. Watson Research
43/*	P.O. Box 704
44/*	Yorktown Heights, NY 10598, USA
45/*--*/
46
47/* System interfaces. */
48
49#include <sys_defs.h>
50#include <sys/socket.h>
51#include <sys/un.h>
52#include <string.h>
53#include <unistd.h>
54#include <sys/stat.h>
55#include <errno.h>
56
57/* Utility library. */
58
59#include "msg.h"
60#include "iostuff.h"
61#include "listen.h"
62#include "sane_accept.h"
63
64/* unix_listen - create UNIX-domain listener */
65
66int     unix_listen(const char *addr, int backlog, int block_mode)
67{
68#undef sun
69    struct sockaddr_un sun;
70    int     len = strlen(addr);
71    int     sock;
72
73    /*
74     * Translate address information to internal form.
75     */
76    if (len >= (int) sizeof(sun.sun_path))
77	msg_fatal("unix-domain name too long: %s", addr);
78    memset((char *) &sun, 0, sizeof(sun));
79    sun.sun_family = AF_UNIX;
80#ifdef HAS_SUN_LEN
81    sun.sun_len = len + 1;
82#endif
83    memcpy(sun.sun_path, addr, len + 1);
84
85    /*
86     * Create a listener socket. Do whatever we can so we don't run into
87     * trouble when this process is restarted after crash.
88     */
89    if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
90	msg_fatal("socket: %m");
91    if (unlink(addr) < 0 && errno != ENOENT)
92	msg_fatal("remove %s: %m", addr);
93    if (bind(sock, (struct sockaddr *) & sun, sizeof(sun)) < 0)
94	msg_fatal("bind: %s: %m", addr);
95#ifdef FCHMOD_UNIX_SOCKETS
96    if (fchmod(sock, 0666) < 0)
97	msg_fatal("fchmod socket %s: %m", addr);
98#else
99    if (chmod(addr, 0666) < 0)
100	msg_fatal("chmod socket %s: %m", addr);
101#endif
102    non_blocking(sock, block_mode);
103    if (listen(sock, backlog) < 0)
104	msg_fatal("listen: %m");
105    return (sock);
106}
107
108/* unix_accept - accept connection */
109
110int     unix_accept(int fd)
111{
112    return (sane_accept(fd, (struct sockaddr *) 0, (SOCKADDR_SIZE *) 0));
113}
114