tests/net/fdpass/fdpass.c

   1 /*      $NetBSD: fdpass.c,v 1.1 2012/08/13 11:15:05 christos Exp $      */
   2 /* $OpenBSD: monitor_fdpass.c,v 1.19 2010/01/12 00:58:25 djm Exp $ */
   3 /*
   4  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __RCSID("$NetBSD: fdpass.c,v 1.1 2012/08/13 11:15:05 christos Exp $");
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <sys/uio.h>
  33 #include <sys/wait.h>
  34
  35 #include <stdio.h>
  36 #include <errno.h>
  37 #include <err.h>
  38 #include <stdlib.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41 #include <poll.h>
  42 #include <string.h>
  43
  44 static int debug;
  45
  46 static int
  47 send_fd(int sock, int fd)
  48 {
  49         struct msghdr msg;
  50         union {
  51                 struct cmsghdr hdr;
  52                 char buf[1024];
  53         } cmsgbuf;
  54         struct cmsghdr *cmsg;
  55         struct iovec vec;
  56         char ch = '\0';
  57         ssize_t n;
  58         struct pollfd pfd;
  59
  60         if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int)))
  61                 errx(1, "%s: %zu < %zu, recompile", __func__,
  62                     sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
  63
  64         memset(&msg, 0, sizeof(msg));
  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                 (void)poll(&pfd, 1, -1);
  84         }
  85         switch (n) {
  86         case -1:
  87                 err(1, "%s: sendmsg(%d)", __func__, fd);
  88         case 1:
  89                 if (debug)
  90                         fprintf(stderr, "%d: send fd %d\n", getpid(), fd);
  91                 return 0;
  92         default:
  93                 errx(1, "%s: sendmsg: expected sent 1 got %ld",
  94                     __func__, (long)n);
  95         }
  96 }
  97
  98 static int
  99 recv_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                 errx(1, "%s: %zu < %zu, recompile", __func__,
 115                     sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
 116
 117         memset(&msg, 0, sizeof(msg));
 118         vec.iov_base = &ch;
 119         vec.iov_len = 1;
 120         msg.msg_iov = &vec;
 121         msg.msg_iovlen = 1;
 122         msg.msg_control = &cmsgbuf.buf;
 123         msg.msg_controllen = CMSG_SPACE(sizeof(int));
 124
 125         pfd.fd = sock;
 126         pfd.events = POLLIN;
 127         while ((n = recvmsg(sock, &msg, 0)) == -1 &&
 128             (errno == EAGAIN || errno == EINTR)) {
 129                 (void)poll(&pfd, 1, -1);
 130         }
 131         switch (n) {
 132         case -1:
 133                 err(1, "%s: recvmsg", __func__);
 134         case 1:
 135                 break;
 136         default:
 137                 errx(1, "%s: recvmsg: expected received 1 got %ld",
 138                     __func__, (long)n);
 139         }
 140
 141         cmsg = CMSG_FIRSTHDR(&msg);
 142         if (cmsg == NULL)
 143                 errx(1, "%s: no message header", __func__);
 144
 145         if (cmsg->cmsg_type != SCM_RIGHTS)
 146                 err(1, "%s: expected type %d got %d", __func__,
 147                     SCM_RIGHTS, cmsg->cmsg_type);
 148         fd = (*(int *)CMSG_DATA(cmsg));
 149         if (debug)
 150                 fprintf(stderr, "%d: recv fd %d\n", getpid(), fd);
 151         return fd;
 152 }
 153
 154 static void usage(void) __attribute__((__noreturn__));
 155
 156 static void
 157 usage(void)
 158 {
 159         fprintf(stderr, "Usage: %s [-vd] -i <input> -o <output>\n"
 160             "\t %s [-v] -p <progname>\n", getprogname(), getprogname());
 161         exit(EXIT_FAILURE);
 162 }
 163
 164 int
 165 main(int argc, char *argv[])
 166 {
 167         int s[2], fd, status, c, verbose;
 168         char buf[1024], *prog;
 169
 170         prog = NULL;
 171         s[0] = s[1] = -1;
 172         verbose = 0;
 173
 174         while ((c = getopt(argc, argv, "di:o:p:")) != -1)
 175                 switch (c) {
 176                 case 'd':
 177                         debug++;
 178                         break;
 179                 case 'i':
 180                         s[0] = atoi(optarg);
 181                         break;
 182                 case 'o':
 183                         s[1] = atoi(optarg);
 184                         break;
 185                 case 'p':
 186                         prog = optarg;
 187                         break;
 188                 default:
 189                         usage();
 190                 }
 191
 192         if ((s[0] == -1 && s[1] != -1) || (s[0] != -1 && s[1] == -1))
 193                 usage();
 194
 195         if (s[0] == -1) {
 196                 if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, s) == -1)
 197                         err(1, "socketpair");
 198         } else
 199                 goto recv;
 200
 201         switch (fork()) {
 202         case -1:
 203                 err(1, "fork");
 204         default:
 205                 fd = open("foo", O_RDWR|O_CREAT|O_TRUNC, 0666);
 206                 if (fd == -1)
 207                         err(1, "open");
 208                 send_fd(s[0], fd);
 209                 wait(&status);
 210                 return 0;
 211         case 0:
 212                 if (prog != NULL) {
 213                         char i[64], o[64];
 214                         snprintf(i, sizeof(i), "%d", s[0]);
 215                         snprintf(o, sizeof(o), "%d", s[1]);
 216                         execlp(prog, prog, "-i", i, "-o", o, NULL);
 217                         err(1, "execlp");
 218                 }
 219         recv:
 220                 fd = recv_fd(s[1]);
 221                 if (verbose) {
 222                         snprintf(buf, sizeof(buf), "ls -l /proc/%d/fd",
 223                             getpid());
 224                         system(buf);
 225                 }
 226                 if (write(fd, "foo\n", 4) == -1)
 227                         err(1, "write");
 228                 close(fd);
 229                 return 0;
 230         }
 231 }