1 /* $NetBSD: monitor_fdpass.c,v 1.9 2021/03/05 17:47:16 christos Exp $ */
2 /* $OpenBSD: monitor_fdpass.c,v 1.22 2020/10/18 11:32:01 djm Exp $ */
3
4 /*
5 * Copyright 2001 Niels Provos <provos@citi.umich.edu>
6 * All rights reserved.
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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "includes.h"
30 __RCSID("$NetBSD: monitor_fdpass.c,v 1.9 2021/03/05 17:47:16 christos Exp $");
31 #include <sys/types.h>
32 #include <sys/socket.h>
33 #include <sys/uio.h>
34
35 #include <errno.h>
36 #include <poll.h>
37 #include <string.h>
38 #include <stdarg.h>
39
40 #include "log.h"
41 #include "monitor_fdpass.h"
42
43 int
mm_send_fd(int sock,int fd)44 mm_send_fd(int sock, int fd)
45 {
46 struct msghdr msg;
47 union {
48 struct cmsghdr hdr;
49 char buf[1024];
50 } cmsgbuf;
51 struct cmsghdr *cmsg;
52 struct iovec vec;
53 char ch = '\0';
54 ssize_t n;
55 struct pollfd pfd;
56
57 if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int))) {
58 error("%s: %zu < %zu, recompile", __func__,
59 sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
60 return -1;
61 }
62
63 memset(&msg, 0, sizeof(msg));
64 memset(&cmsgbuf, 0, sizeof(cmsgbuf));
65 msg.msg_control = &cmsgbuf.buf;
66 msg.msg_controllen = CMSG_SPACE(sizeof(int));
67 cmsg = CMSG_FIRSTHDR(&msg);
68 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
69 cmsg->cmsg_level = SOL_SOCKET;
70 cmsg->cmsg_type = SCM_RIGHTS;
71 *(int *)CMSG_DATA(cmsg) = fd;
72 msg.msg_controllen = cmsg->cmsg_len;
73
74 vec.iov_base = &ch;
75 vec.iov_len = 1;
76 msg.msg_iov = &vec;
77 msg.msg_iovlen = 1;
78
79 pfd.fd = sock;
80 pfd.events = POLLOUT;
81 while ((n = sendmsg(sock, &msg, 0)) == -1 &&
82 (errno == EAGAIN || errno == EINTR)) {
83 debug3_f("sendmsg(%d): %s", fd, strerror(errno));
84 (void)poll(&pfd, 1, -1);
85 }
86 if (n == -1) {
87 error_f("sendmsg(%d): %s", fd, strerror(errno));
88 return -1;
89 }
90
91 if (n != 1) {
92 error_f("sendmsg: expected sent 1 got %zd", n);
93 return -1;
94 }
95 return 0;
96 }
97
98 int
mm_receive_fd(int sock)99 mm_receive_fd(int sock)
100 {
101 struct msghdr msg;
102 union {
103 struct cmsghdr hdr;
104 char buf[1024];
105 } cmsgbuf;
106 struct cmsghdr *cmsg;
107 struct iovec vec;
108 ssize_t n;
109 char ch;
110 int fd;
111 struct pollfd pfd;
112
113 if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int))) {
114 error("%s: %zu < %zu, recompile", __func__,
115 sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
116 return -1;
117 }
118
119 memset(&msg, 0, sizeof(msg));
120 memset(&cmsgbuf, 0, sizeof(cmsgbuf));
121 vec.iov_base = &ch;
122 vec.iov_len = 1;
123 msg.msg_iov = &vec;
124 msg.msg_iovlen = 1;
125 msg.msg_control = &cmsgbuf.buf;
126 msg.msg_controllen = CMSG_SPACE(sizeof(int));
127
128 pfd.fd = sock;
129 pfd.events = POLLIN;
130 while ((n = recvmsg(sock, &msg, 0)) == -1 &&
131 (errno == EAGAIN || errno == EINTR)) {
132 debug3_f("recvmsg: %s", strerror(errno));
133 (void)poll(&pfd, 1, -1);
134 }
135 if (n == -1) {
136 error_f("recvmsg: %s", strerror(errno));
137 return -1;
138 }
139
140 if (n != 1) {
141 error_f("recvmsg: expected received 1 got %zd", n);
142 return -1;
143 }
144
145 cmsg = CMSG_FIRSTHDR(&msg);
146 if (cmsg == NULL) {
147 error_f("no message header");
148 return -1;
149 }
150
151 if (cmsg->cmsg_type != SCM_RIGHTS) {
152 error_f("expected %d got %d", SCM_RIGHTS, cmsg->cmsg_type);
153 return -1;
154 }
155 fd = (*(int *)CMSG_DATA(cmsg));
156 return fd;
157 }
158