1/*-
2 * Copyright (c) 2012 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by Pawel Jakub Dawidek under sponsorship from
6 * the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/types.h>
31#include <sys/select.h>
32#include <sys/socket.h>
33
34#include <assert.h>
35#include <errno.h>
36#include <stdlib.h>
37#include <strings.h>
38
39#include "misc.h"
40
41int
42pdwait(int pfd)
43{
44	fd_set fdset;
45
46	FD_ZERO(&fdset);
47	FD_SET(pfd, &fdset);
48
49	return (select(pfd + 1, NULL, &fdset, NULL, NULL) == -1 ? -1 : 0);
50}
51
52int
53descriptor_send(int sock, int fd)
54{
55	unsigned char ctrl[CMSG_SPACE(sizeof(fd))];
56	struct msghdr msg;
57	struct cmsghdr *cmsg;
58
59	assert(sock >= 0);
60	assert(fd >= 0);
61
62	bzero(&msg, sizeof(msg));
63	bzero(&ctrl, sizeof(ctrl));
64
65	msg.msg_iov = NULL;
66	msg.msg_iovlen = 0;
67	msg.msg_control = ctrl;
68	msg.msg_controllen = sizeof(ctrl);
69
70	cmsg = CMSG_FIRSTHDR(&msg);
71	cmsg->cmsg_level = SOL_SOCKET;
72	cmsg->cmsg_type = SCM_RIGHTS;
73	cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
74	bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd));
75
76	if (sendmsg(sock, &msg, 0) == -1)
77		return (errno);
78
79	return (0);
80}
81
82int
83descriptor_recv(int sock, int *fdp)
84{
85	unsigned char ctrl[CMSG_SPACE(sizeof(*fdp))];
86	struct msghdr msg;
87	struct cmsghdr *cmsg;
88	struct iovec iov;
89	int val;
90
91	assert(sock >= 0);
92	assert(fdp != NULL);
93
94	bzero(&msg, sizeof(msg));
95	bzero(&ctrl, sizeof(ctrl));
96
97#if 1
98	/*
99	 * This doesn't really make sense, as we don't plan to receive any
100	 * data, but if no buffer is provided and recv(2) returns 0 without
101	 * control message. Must be kernel bug.
102	 */
103	iov.iov_base = &val;
104	iov.iov_len = sizeof(val);
105	msg.msg_iov = &iov;
106	msg.msg_iovlen = 1;
107#else
108	msg.msg_iov = NULL;
109	msg.msg_iovlen = 0;
110#endif
111	msg.msg_control = ctrl;
112	msg.msg_controllen = sizeof(ctrl);
113
114	if (recvmsg(sock, &msg, 0) == -1)
115		return (errno);
116
117	cmsg = CMSG_FIRSTHDR(&msg);
118	if (cmsg == NULL || cmsg->cmsg_level != SOL_SOCKET ||
119	    cmsg->cmsg_type != SCM_RIGHTS) {
120		return (EINVAL);
121	}
122	bcopy(CMSG_DATA(cmsg), fdp, sizeof(*fdp));
123
124	return (0);
125}
126