1 /* $OpenBSD: monitor_fdpass.c,v 1.21 2016/02/29 20:22:36 jca Exp $ */ 2 /* 3 * Copyright 2001 Niels Provos <provos (at) 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 %zd", __func__, n); 103 return -1; 104 } 105 return 0; 106 #else 107 error("%s: file descriptor passing not supported", __func__); 108 return -1; 109 #endif 110 } 111 112 int 113 mm_receive_fd(int sock) 114 { 115 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR)) 116 struct msghdr msg; 117 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR 118 union { 119 struct cmsghdr hdr; 120 char buf[CMSG_SPACE(sizeof(int))]; 121 } cmsgbuf; 122 struct cmsghdr *cmsg; 123 #endif 124 struct iovec vec; 125 ssize_t n; 126 char ch; 127 int fd; 128 struct pollfd pfd; 129 130 memset(&msg, 0, sizeof(msg)); 131 vec.iov_base = &ch; 132 vec.iov_len = 1; 133 msg.msg_iov = &vec; 134 msg.msg_iovlen = 1; 135 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 136 msg.msg_accrights = (caddr_t)&fd; 137 msg.msg_accrightslen = sizeof(fd); 138 #else 139 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 140 msg.msg_control = &cmsgbuf.buf; 141 msg.msg_controllen = sizeof(cmsgbuf.buf); 142 #endif 143 144 pfd.fd = sock; 145 pfd.events = POLLIN; 146 while ((n = recvmsg(sock, &msg, 0)) == -1 && 147 (errno == EAGAIN || errno == EINTR)) { 148 debug3("%s: recvmsg: %s", __func__, strerror(errno)); 149 (void)poll(&pfd, 1, -1); 150 } 151 if (n == -1) { 152 error("%s: recvmsg: %s", __func__, strerror(errno)); 153 return -1; 154 } 155 156 if (n != 1) { 157 error("%s: recvmsg: expected received 1 got %zd", __func__, n); 158 return -1; 159 } 160 161 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 162 if (msg.msg_accrightslen != sizeof(fd)) { 163 error("%s: no fd", __func__); 164 return -1; 165 } 166 #else 167 cmsg = CMSG_FIRSTHDR(&msg); 168 if (cmsg == NULL) { 169 error("%s: no message header", __func__); 170 return -1; 171 } 172 173 #ifndef BROKEN_CMSG_TYPE 174 if (cmsg->cmsg_type != SCM_RIGHTS) { 175 error("%s: expected type %d got %d", __func__, 176 SCM_RIGHTS, cmsg->cmsg_type); 177 return -1; 178 } 179 #endif 180 fd = (*(int *)CMSG_DATA(cmsg)); 181 #endif 182 return fd; 183 #else 184 error("%s: file descriptor passing not supported", __func__); 185 return -1; 186 #endif 187 } 188
