1 /* $NetBSD: monitor_fdpass.c,v 1.7 2016/12/25 00:07:47 christos Exp $ */ 2 /* $OpenBSD: monitor_fdpass.c,v 1.21 2016/02/29 20:22:36 jca Exp $ */ 3 /* 4 * Copyright 2001 Niels Provos <provos@citi.umich.edu> 5 * All rights reserved. 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 AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 __RCSID("$NetBSD: monitor_fdpass.c,v 1.7 2016/12/25 00:07:47 christos Exp $"); 30 #include <sys/types.h> 31 #include <sys/socket.h> 32 #include <sys/uio.h> 33 34 #include <errno.h> 35 #include <poll.h> 36 #include <string.h> 37 #include <stdarg.h> 38 39 #include "log.h" 40 #include "monitor_fdpass.h" 41 42 int 43 mm_send_fd(int sock, int fd) 44 { 45 struct msghdr msg; 46 union { 47 struct cmsghdr hdr; 48 char buf[1024]; 49 } cmsgbuf; 50 struct cmsghdr *cmsg; 51 struct iovec vec; 52 char ch = '\0'; 53 ssize_t n; 54 struct pollfd pfd; 55 56 if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int))) { 57 error("%s: %zu < %zu, recompile", __func__, 58 sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int))); 59 return -1; 60 } 61 62 memset(&msg, 0, sizeof(msg)); 63 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 64 msg.msg_control = &cmsgbuf.buf; 65 msg.msg_controllen = CMSG_SPACE(sizeof(int)); 66 cmsg = CMSG_FIRSTHDR(&msg); 67 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 68 cmsg->cmsg_level = SOL_SOCKET; 69 cmsg->cmsg_type = SCM_RIGHTS; 70 *(int *)CMSG_DATA(cmsg) = fd; 71 msg.msg_controllen = cmsg->cmsg_len; 72 73 vec.iov_base = &ch; 74 vec.iov_len = 1; 75 msg.msg_iov = &vec; 76 msg.msg_iovlen = 1; 77 78 pfd.fd = sock; 79 pfd.events = POLLOUT; 80 while ((n = sendmsg(sock, &msg, 0)) == -1 && 81 (errno == EAGAIN || errno == EINTR)) { 82 debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno)); 83 (void)poll(&pfd, 1, -1); 84 } 85 if (n == -1) { 86 error("%s: sendmsg(%d): %s", __func__, fd, 87 strerror(errno)); 88 return -1; 89 } 90 91 if (n != 1) { 92 error("%s: sendmsg: expected sent 1 got %zd", __func__, n); 93 return -1; 94 } 95 return 0; 96 } 97 98 int 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("%s: recvmsg: %s", __func__, strerror(errno)); 133 (void)poll(&pfd, 1, -1); 134 } 135 if (n == -1) { 136 error("%s: recvmsg: %s", __func__, strerror(errno)); 137 return -1; 138 } 139 140 if (n != 1) { 141 error("%s: recvmsg: expected received 1 got %zd", __func__, n); 142 return -1; 143 } 144 145 cmsg = CMSG_FIRSTHDR(&msg); 146 if (cmsg == NULL) { 147 error("%s: no message header", __func__); 148 return -1; 149 } 150 151 if (cmsg->cmsg_type != SCM_RIGHTS) { 152 error("%s: expected type %d got %d", __func__, 153 SCM_RIGHTS, cmsg->cmsg_type); 154 return -1; 155 } 156 fd = (*(int *)CMSG_DATA(cmsg)); 157 return fd; 158 } 159