1 /* $OpenBSD: monitor_fdpass.c,v 1.20 2015/02/25 23:05:47 djm Exp $ */ 2 /* 3 * Copyright 2001 Niels Provos <provos@citi.umich.edu> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <sys/uio.h> 32 #ifdef HAVE_SYS_UN_H 33 #include <sys/un.h> 34 #endif 35 36 #include <errno.h> 37 #include <string.h> 38 #include <stdarg.h> 39 40 #ifdef HAVE_POLL_H 41 # include <poll.h> 42 #else 43 # ifdef HAVE_SYS_POLL_H 44 # include <sys/poll.h> 45 # endif 46 #endif 47 48 #include "log.h" 49 #include "monitor_fdpass.h" 50 51 int 52 mm_send_fd(int sock, int fd) 53 { 54 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR)) 55 struct msghdr msg; 56 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR 57 union { 58 struct cmsghdr hdr; 59 char buf[CMSG_SPACE(sizeof(int))]; 60 } cmsgbuf; 61 struct cmsghdr *cmsg; 62 #endif 63 struct iovec vec; 64 char ch = '\0'; 65 ssize_t n; 66 struct pollfd pfd; 67 68 memset(&msg, 0, sizeof(msg)); 69 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 70 msg.msg_accrights = (caddr_t)&fd; 71 msg.msg_accrightslen = sizeof(fd); 72 #else 73 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 74 msg.msg_control = (caddr_t)&cmsgbuf.buf; 75 msg.msg_controllen = sizeof(cmsgbuf.buf); 76 cmsg = CMSG_FIRSTHDR(&msg); 77 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 78 cmsg->cmsg_level = SOL_SOCKET; 79 cmsg->cmsg_type = SCM_RIGHTS; 80 *(int *)CMSG_DATA(cmsg) = fd; 81 #endif 82 83 vec.iov_base = &ch; 84 vec.iov_len = 1; 85 msg.msg_iov = &vec; 86 msg.msg_iovlen = 1; 87 88 pfd.fd = sock; 89 pfd.events = POLLOUT; 90 while ((n = sendmsg(sock, &msg, 0)) == -1 && 91 (errno == EAGAIN || errno == EINTR)) { 92 debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno)); 93 (void)poll(&pfd, 1, -1); 94 } 95 if (n == -1) { 96 error("%s: sendmsg(%d): %s", __func__, fd, 97 strerror(errno)); 98 return -1; 99 } 100 101 if (n != 1) { 102 error("%s: sendmsg: expected sent 1 got %ld", 103 __func__, (long)n); 104 return -1; 105 } 106 return 0; 107 #else 108 error("%s: file descriptor passing not supported", __func__); 109 return -1; 110 #endif 111 } 112 113 int 114 mm_receive_fd(int sock) 115 { 116 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR)) 117 struct msghdr msg; 118 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR 119 union { 120 struct cmsghdr hdr; 121 char buf[CMSG_SPACE(sizeof(int))]; 122 } cmsgbuf; 123 struct cmsghdr *cmsg; 124 #endif 125 struct iovec vec; 126 ssize_t n; 127 char ch; 128 int fd; 129 struct pollfd pfd; 130 131 memset(&msg, 0, sizeof(msg)); 132 vec.iov_base = &ch; 133 vec.iov_len = 1; 134 msg.msg_iov = &vec; 135 msg.msg_iovlen = 1; 136 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 137 msg.msg_accrights = (caddr_t)&fd; 138 msg.msg_accrightslen = sizeof(fd); 139 #else 140 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 141 msg.msg_control = &cmsgbuf.buf; 142 msg.msg_controllen = sizeof(cmsgbuf.buf); 143 #endif 144 145 pfd.fd = sock; 146 pfd.events = POLLIN; 147 while ((n = recvmsg(sock, &msg, 0)) == -1 && 148 (errno == EAGAIN || errno == EINTR)) { 149 debug3("%s: recvmsg: %s", __func__, strerror(errno)); 150 (void)poll(&pfd, 1, -1); 151 } 152 if (n == -1) { 153 error("%s: recvmsg: %s", __func__, strerror(errno)); 154 return -1; 155 } 156 157 if (n != 1) { 158 error("%s: recvmsg: expected received 1 got %ld", 159 __func__, (long)n); 160 return -1; 161 } 162 163 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 164 if (msg.msg_accrightslen != sizeof(fd)) { 165 error("%s: no fd", __func__); 166 return -1; 167 } 168 #else 169 cmsg = CMSG_FIRSTHDR(&msg); 170 if (cmsg == NULL) { 171 error("%s: no message header", __func__); 172 return -1; 173 } 174 175 #ifndef BROKEN_CMSG_TYPE 176 if (cmsg->cmsg_type != SCM_RIGHTS) { 177 error("%s: expected type %d got %d", __func__, 178 SCM_RIGHTS, cmsg->cmsg_type); 179 return -1; 180 } 181 #endif 182 fd = (*(int *)CMSG_DATA(cmsg)); 183 #endif 184 return fd; 185 #else 186 error("%s: file descriptor passing not supported", __func__); 187 return -1; 188 #endif 189 } 190