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