monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.18 2008/11/30 11:59:26 dtucker 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 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  49         union {
  50                 struct cmsghdr hdr;
  51                 char buf[CMSG_SPACE(sizeof(int))];
  52         } cmsgbuf;
  53         struct cmsghdr *cmsg;
  54 #endif
  55         struct iovec vec;
  56         char ch = '\0';
  57         ssize_t n;
  58
  59         memset(&msg, 0, sizeof(msg));
  60 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  61         msg.msg_accrights = (caddr_t)&fd;
  62         msg.msg_accrightslen = sizeof(fd);
  63 #else
  64         msg.msg_control = (caddr_t)&cmsgbuf.buf;
  65         msg.msg_controllen = sizeof(cmsgbuf.buf);
  66         cmsg = CMSG_FIRSTHDR(&msg);
  67         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  68         cmsg->cmsg_level = SOL_SOCKET;
  69         cmsg->cmsg_type = SCM_RIGHTS;
  70         *(int *)CMSG_DATA(cmsg) = fd;
  71 #endif
  72
  73         vec.iov_base = &ch;
  74         vec.iov_len = 1;
  75         msg.msg_iov = &vec;
  76         msg.msg_iovlen = 1;
  77
  78         while ((n = sendmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
  79             errno == EINTR))
  80                 debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
  81         if (n == -1) {
  82                 error("%s: sendmsg(%d): %s", __func__, fd,
  83                     strerror(errno));
  84                 return -1;
  85         }
  86
  87         if (n != 1) {
  88                 error("%s: sendmsg: expected sent 1 got %ld",
  89                     __func__, (long)n);
  90                 return -1;
  91         }
  92         return 0;
  93 #else
  94         error("%s: file descriptor passing not supported", __func__);
  95         return -1;
  96 #endif
  97 }
  98
  99 int
 100 mm_receive_fd(int sock)
 101 {
 102 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
 103         struct msghdr msg;
 104 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
 105         union {
 106                 struct cmsghdr hdr;
 107                 char buf[CMSG_SPACE(sizeof(int))];
 108         } cmsgbuf;
 109         struct cmsghdr *cmsg;
 110 #endif
 111         struct iovec vec;
 112         ssize_t n;
 113         char ch;
 114         int fd;
 115
 116         memset(&msg, 0, sizeof(msg));
 117         vec.iov_base = &ch;
 118         vec.iov_len = 1;
 119         msg.msg_iov = &vec;
 120         msg.msg_iovlen = 1;
 121 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 122         msg.msg_accrights = (caddr_t)&fd;
 123         msg.msg_accrightslen = sizeof(fd);
 124 #else
 125         msg.msg_control = &cmsgbuf.buf;
 126         msg.msg_controllen = sizeof(cmsgbuf.buf);
 127 #endif
 128
 129         while ((n = recvmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
 130             errno == EINTR))
 131                 debug3("%s: recvmsg: %s", __func__, strerror(errno));
 132         if (n == -1) {
 133                 error("%s: recvmsg: %s", __func__, strerror(errno));
 134                 return -1;
 135         }
 136
 137         if (n != 1) {
 138                 error("%s: recvmsg: expected received 1 got %ld",
 139                     __func__, (long)n);
 140                 return -1;
 141         }
 142
 143 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 144         if (msg.msg_accrightslen != sizeof(fd)) {
 145                 error("%s: no fd", __func__);
 146                 return -1;
 147         }
 148 #else
 149         cmsg = CMSG_FIRSTHDR(&msg);
 150         if (cmsg == NULL) {
 151                 error("%s: no message header", __func__);
 152                 return -1;
 153         }
 154
 155 #ifndef BROKEN_CMSG_TYPE
 156         if (cmsg->cmsg_type != SCM_RIGHTS) {
 157                 error("%s: expected type %d got %d", __func__,
 158                     SCM_RIGHTS, cmsg->cmsg_type);
 159                 return -1;
 160         }
 161 #endif
 162         fd = (*(int *)CMSG_DATA(cmsg));
 163 #endif
 164         return fd;
 165 #else
 166         error("%s: file descriptor passing not supported", __func__);
 167         return -1;
 168 #endif
 169 }