monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.13 2007/09/04 03:21:03 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 #include "log.h"
  41 #include "monitor_fdpass.h"
  42
  43 int
  44 mm_send_fd(int sock, int fd)
  45 {
  46 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  47         struct msghdr msg;
  48         struct iovec vec;
  49         char ch = '\0';
  50         ssize_t n;
  51 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  52         char tmp[CMSG_SPACE(sizeof(int))];
  53         struct cmsghdr *cmsg;
  54 #endif
  55
  56         memset(&msg, 0, sizeof(msg));
  57 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  58         msg.msg_accrights = (caddr_t)&fd;
  59         msg.msg_accrightslen = sizeof(fd);
  60 #else
  61         msg.msg_control = (caddr_t)tmp;
  62         msg.msg_controllen = CMSG_LEN(sizeof(int));
  63         cmsg = CMSG_FIRSTHDR(&msg);
  64         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  65         cmsg->cmsg_level = SOL_SOCKET;
  66         cmsg->cmsg_type = SCM_RIGHTS;
  67         *(int *)CMSG_DATA(cmsg) = fd;
  68 #endif
  69
  70         vec.iov_base = &ch;
  71         vec.iov_len = 1;
  72         msg.msg_iov = &vec;
  73         msg.msg_iovlen = 1;
  74
  75         if ((n = sendmsg(sock, &msg, 0)) == -1) {
  76                 error("%s: sendmsg(%d): %s", __func__, fd,
  77                     strerror(errno));
  78                 return -1;
  79         }
  80
  81         if (n != 1) {
  82                 error("%s: sendmsg: expected sent 1 got %ld",
  83                     __func__, (long)n);
  84                 return -1;
  85         }
  86         return 0;
  87 #else
  88         error("%s: file descriptor passing not supported", __func__);
  89         return -1;
  90 #endif
  91 }
  92
  93 int
  94 mm_receive_fd(int sock)
  95 {
  96 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  97         struct msghdr msg;
  98         struct iovec vec;
  99         ssize_t n;
 100         char ch;
 101         int fd;
 102 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
 103         char tmp[CMSG_SPACE(sizeof(int))];
 104         struct cmsghdr *cmsg;
 105 #endif
 106
 107         memset(&msg, 0, sizeof(msg));
 108         vec.iov_base = &ch;
 109         vec.iov_len = 1;
 110         msg.msg_iov = &vec;
 111         msg.msg_iovlen = 1;
 112 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 113         msg.msg_accrights = (caddr_t)&fd;
 114         msg.msg_accrightslen = sizeof(fd);
 115 #else
 116         msg.msg_control = tmp;
 117         msg.msg_controllen = sizeof(tmp);
 118 #endif
 119
 120         if ((n = recvmsg(sock, &msg, 0)) == -1) {
 121                 error("%s: recvmsg: %s", __func__, strerror(errno));
 122                 return -1;
 123         }
 124         if (n != 1) {
 125                 error("%s: recvmsg: expected received 1 got %ld",
 126                     __func__, (long)n);
 127                 return -1;
 128         }
 129
 130 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 131         if (msg.msg_accrightslen != sizeof(fd)) {
 132                 error("%s: no fd", __func__);
 133                 return -1;
 134         }
 135 #else
 136         cmsg = CMSG_FIRSTHDR(&msg);
 137         if (cmsg == NULL) {
 138                 error("%s: no message header", __func__);
 139                 return -1;
 140         }
 141 #ifndef BROKEN_CMSG_TYPE
 142         if (cmsg->cmsg_type != SCM_RIGHTS) {
 143                 error("%s: expected type %d got %d", __func__,
 144                     SCM_RIGHTS, cmsg->cmsg_type);
 145                 return -1;
 146         }
 147 #endif
 148         fd = (*(int *)CMSG_DATA(cmsg));
 149 #endif
 150         return fd;
 151 #else
 152         error("%s: file descriptor passing not supported", __func__);
 153         return -1;
 154 #endif
 155 }