monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.19 2010/01/12 00:58:25 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 #ifdef HAVE_POLL_H
  38 #include <poll.h>
  39 #endif
  40 #include <string.h>
  41 #include <stdarg.h>
  42
  43 #include "log.h"
  44 #include "monitor_fdpass.h"
  45
  46 int
  47 mm_send_fd(int sock, int fd)
  48 {
  49 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  50         struct msghdr msg;
  51 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  52         union {
  53                 struct cmsghdr hdr;
  54                 char buf[CMSG_SPACE(sizeof(int))];
  55         } cmsgbuf;
  56         struct cmsghdr *cmsg;
  57 #endif
  58         struct iovec vec;
  59         char ch = '\0';
  60         ssize_t n;
  61         struct pollfd pfd;
  62
  63         memset(&msg, 0, sizeof(msg));
  64 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  65         msg.msg_accrights = (caddr_t)&fd;
  66         msg.msg_accrightslen = sizeof(fd);
  67 #else
  68         msg.msg_control = (caddr_t)&cmsgbuf.buf;
  69         msg.msg_controllen = sizeof(cmsgbuf.buf);
  70         cmsg = CMSG_FIRSTHDR(&msg);
  71         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  72         cmsg->cmsg_level = SOL_SOCKET;
  73         cmsg->cmsg_type = SCM_RIGHTS;
  74         *(int *)CMSG_DATA(cmsg) = fd;
  75 #endif
  76
  77         vec.iov_base = &ch;
  78         vec.iov_len = 1;
  79         msg.msg_iov = &vec;
  80         msg.msg_iovlen = 1;
  81
  82         pfd.fd = sock;
  83         pfd.events = POLLOUT;
  84         while ((n = sendmsg(sock, &msg, 0)) == -1 &&
  85             (errno == EAGAIN || errno == EINTR)) {
  86                 debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
  87                 (void)poll(&pfd, 1, -1);
  88         }
  89         if (n == -1) {
  90                 error("%s: sendmsg(%d): %s", __func__, fd,
  91                     strerror(errno));
  92                 return -1;
  93         }
  94
  95         if (n != 1) {
  96                 error("%s: sendmsg: expected sent 1 got %ld",
  97                     __func__, (long)n);
  98                 return -1;
  99         }
 100         return 0;
 101 #else
 102         error("%s: file descriptor passing not supported", __func__);
 103         return -1;
 104 #endif
 105 }
 106
 107 int
 108 mm_receive_fd(int sock)
 109 {
 110 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
 111         struct msghdr msg;
 112 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
 113         union {
 114                 struct cmsghdr hdr;
 115                 char buf[CMSG_SPACE(sizeof(int))];
 116         } cmsgbuf;
 117         struct cmsghdr *cmsg;
 118 #endif
 119         struct iovec vec;
 120         ssize_t n;
 121         char ch;
 122         int fd;
 123         struct pollfd pfd;
 124
 125         memset(&msg, 0, sizeof(msg));
 126         vec.iov_base = &ch;
 127         vec.iov_len = 1;
 128         msg.msg_iov = &vec;
 129         msg.msg_iovlen = 1;
 130 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 131         msg.msg_accrights = (caddr_t)&fd;
 132         msg.msg_accrightslen = sizeof(fd);
 133 #else
 134         msg.msg_control = &cmsgbuf.buf;
 135         msg.msg_controllen = sizeof(cmsgbuf.buf);
 136 #endif
 137
 138         pfd.fd = sock;
 139         pfd.events = POLLIN;
 140         while ((n = recvmsg(sock, &msg, 0)) == -1 &&
 141             (errno == EAGAIN || errno == EINTR)) {
 142                 debug3("%s: recvmsg: %s", __func__, strerror(errno));
 143                 (void)poll(&pfd, 1, -1);
 144         }
 145         if (n == -1) {
 146                 error("%s: recvmsg: %s", __func__, strerror(errno));
 147                 return -1;
 148         }
 149
 150         if (n != 1) {
 151                 error("%s: recvmsg: expected received 1 got %ld",
 152                     __func__, (long)n);
 153                 return -1;
 154         }
 155
 156 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 157         if (msg.msg_accrightslen != sizeof(fd)) {
 158                 error("%s: no fd", __func__);
 159                 return -1;
 160         }
 161 #else
 162         cmsg = CMSG_FIRSTHDR(&msg);
 163         if (cmsg == NULL) {
 164                 error("%s: no message header", __func__);
 165                 return -1;
 166         }
 167
 168 #ifndef BROKEN_CMSG_TYPE
 169         if (cmsg->cmsg_type != SCM_RIGHTS) {
 170                 error("%s: expected type %d got %d", __func__,
 171                     SCM_RIGHTS, cmsg->cmsg_type);
 172                 return -1;
 173         }
 174 #endif
 175         fd = (*(int *)CMSG_DATA(cmsg));
 176 #endif
 177         return fd;
 178 #else
 179         error("%s: file descriptor passing not supported", __func__);
 180         return -1;
 181 #endif
 182 }