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 43int 44mm_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 98int 99mm_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