1/*	$NetBSD: pass_trigger.c,v 1.2 2017/02/14 01:16:49 christos Exp $	*/
2
3/*++
4/* NAME
5/*	pass_trigger 3
6/* SUMMARY
7/*	trigger file descriptor listener
8/* SYNOPSIS
9/*	#include <trigger.h>
10/*
11/*	int	pass_trigger(service, buf, len, timeout)
12/*	const char *service;
13/*	const char *buf;
14/*	ssize_t	len;
15/*	int	timeout;
16/* DESCRIPTION
17/*	pass_trigger() connects to the named local server by sending
18/*	a file descriptor to it and writing the named buffer.
19/*
20/*	The connection is closed by a background thread. Some kernels
21/*	cannot handle client-side disconnect before the server has
22/*	received the message.
23/*
24/*	Arguments:
25/* .IP service
26/*	Name of the communication endpoint.
27/* .IP buf
28/*	Address of data to be written.
29/* .IP len
30/*	Amount of data to be written.
31/* .IP timeout
32/*	Deadline in seconds. Specify a value <= 0 to disable
33/*	the time limit.
34/* DIAGNOSTICS
35/*	The result is zero in case of success, -1 in case of problems.
36/* SEE ALSO
37/*	unix_connect(3), local client
38/*	stream_connect(3), streams-based client
39/* LICENSE
40/* .ad
41/* .fi
42/*	The Secure Mailer license must be distributed with this software.
43/* AUTHOR(S)
44/*	Wietse Venema
45/*	IBM T.J. Watson Research
46/*	P.O. Box 704
47/*	Yorktown Heights, NY 10598, USA
48/*--*/
49
50/* System library. */
51
52#include <sys_defs.h>
53#include <sys/socket.h>
54#include <unistd.h>
55#include <string.h>
56
57/* Utility library. */
58
59#include <msg.h>
60#include <connect.h>
61#include <iostuff.h>
62#include <mymalloc.h>
63#include <events.h>
64#include <trigger.h>
65
66struct pass_trigger {
67    int     connect_fd;
68    char   *service;
69    int     pass_fd[2];
70};
71
72/* pass_trigger_event - disconnect from peer */
73
74static void pass_trigger_event(int event, void *context)
75{
76    struct pass_trigger *pp = (struct pass_trigger *) context;
77    static const char *myname = "pass_trigger_event";
78
79    /*
80     * Disconnect.
81     */
82    if (event == EVENT_TIME)
83	msg_warn("%s: read timeout for service %s", myname, pp->service);
84    event_disable_readwrite(pp->connect_fd);
85    event_cancel_timer(pass_trigger_event, context);
86    /* Don't combine multiple close() calls into one boolean expression. */
87    if (close(pp->connect_fd) < 0)
88	msg_warn("%s: close %s: %m", myname, pp->service);
89    if (close(pp->pass_fd[0]) < 0)
90	msg_warn("%s: close pipe: %m", myname);
91    if (close(pp->pass_fd[1]) < 0)
92	msg_warn("%s: close pipe: %m", myname);
93    myfree(pp->service);
94    myfree((void *) pp);
95}
96
97/* pass_trigger - wakeup local server */
98
99int     pass_trigger(const char *service, const char *buf, ssize_t len, int timeout)
100{
101    const char *myname = "pass_trigger";
102    int     pass_fd[2];
103    struct pass_trigger *pp;
104    int     connect_fd;
105
106    if (msg_verbose > 1)
107	msg_info("%s: service %s", myname, service);
108
109    /*
110     * Connect...
111     */
112    if ((connect_fd = LOCAL_CONNECT(service, BLOCKING, timeout)) < 0) {
113	if (msg_verbose)
114	    msg_warn("%s: connect to %s: %m", myname, service);
115	return (-1);
116    }
117    close_on_exec(connect_fd, CLOSE_ON_EXEC);
118
119    /*
120     * Create a pipe, and send one pipe end to the server.
121     */
122    if (pipe(pass_fd) < 0)
123	msg_fatal("%s: pipe: %m", myname);
124    close_on_exec(pass_fd[0], CLOSE_ON_EXEC);
125    close_on_exec(pass_fd[1], CLOSE_ON_EXEC);
126    if (LOCAL_SEND_FD(connect_fd, pass_fd[0]) < 0)
127	msg_fatal("%s: send file descriptor: %m", myname);
128
129    /*
130     * Stash away context.
131     */
132    pp = (struct pass_trigger *) mymalloc(sizeof(*pp));
133    pp->connect_fd = connect_fd;
134    pp->service = mystrdup(service);
135    pp->pass_fd[0] = pass_fd[0];
136    pp->pass_fd[1] = pass_fd[1];
137
138    /*
139     * Write the request...
140     */
141    if (write_buf(pass_fd[1], buf, len, timeout) < 0
142	|| write_buf(pass_fd[1], "", 1, timeout) < 0)
143	if (msg_verbose)
144	    msg_warn("%s: write to %s: %m", myname, service);
145
146    /*
147     * Wakeup when the peer disconnects, or when we lose patience.
148     */
149    if (timeout > 0)
150	event_request_timer(pass_trigger_event, (void *) pp, timeout + 100);
151    event_enable_read(connect_fd, pass_trigger_event, (void *) pp);
152    return (0);
153}
154