minix/tests/net/fdpass/fdpass.c

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/* $NetBSD: fdpass.c,v 1.1 2012/08/13 11:15:05 christos Exp $ */
/* $OpenBSD: monitor_fdpass.c,v 1.19 2010/01/12 00:58:25 djm Exp $ */
/*
* Copyright 2001 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: fdpass.c,v 1.1 2012/08/13 11:15:05 christos Exp $");
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <stdio.h>
#include <errno.h>
#include <err.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#include <string.h>
static int debug;
static int
send_fd(int sock, int fd)
{
struct msghdr msg;
union {
struct cmsghdr hdr;
char buf[1024];
} cmsgbuf;
struct cmsghdr *cmsg;
struct iovec vec;
char ch = '\0';
ssize_t n;
struct pollfd pfd;
if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int)))
errx(1, "%s: %zu < %zu, recompile", __func__,
sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
memset(&msg, 0, sizeof(msg));
msg.msg_control = &cmsgbuf.buf;
msg.msg_controllen = CMSG_SPACE(sizeof(int));
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
*(int *)CMSG_DATA(cmsg) = fd;
msg.msg_controllen = cmsg->cmsg_len;
vec.iov_base = &ch;
vec.iov_len = 1;
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
pfd.fd = sock;
pfd.events = POLLOUT;
while ((n = sendmsg(sock, &msg, 0)) == -1 &&
(errno == EAGAIN || errno == EINTR)) {
(void)poll(&pfd, 1, -1);
}
switch (n) {
case -1:
err(1, "%s: sendmsg(%d)", __func__, fd);
case 1:
if (debug)
fprintf(stderr, "%d: send fd %d\n", getpid(), fd);
return 0;
default:
errx(1, "%s: sendmsg: expected sent 1 got %ld",
__func__, (long)n);
}
}
static int
recv_fd(int sock)
{
struct msghdr msg;
union {
struct cmsghdr hdr;
char buf[1024];
} cmsgbuf;
struct cmsghdr *cmsg;
struct iovec vec;
ssize_t n;
char ch;
int fd;
struct pollfd pfd;
if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int)))
errx(1, "%s: %zu < %zu, recompile", __func__,
sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
memset(&msg, 0, sizeof(msg));
vec.iov_base = &ch;
vec.iov_len = 1;
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
msg.msg_control = &cmsgbuf.buf;
msg.msg_controllen = CMSG_SPACE(sizeof(int));
pfd.fd = sock;
pfd.events = POLLIN;
while ((n = recvmsg(sock, &msg, 0)) == -1 &&
(errno == EAGAIN || errno == EINTR)) {
(void)poll(&pfd, 1, -1);
}
switch (n) {
case -1:
err(1, "%s: recvmsg", __func__);
case 1:
break;
default:
errx(1, "%s: recvmsg: expected received 1 got %ld",
__func__, (long)n);
}
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg == NULL)
errx(1, "%s: no message header", __func__);
if (cmsg->cmsg_type != SCM_RIGHTS)
err(1, "%s: expected type %d got %d", __func__,
SCM_RIGHTS, cmsg->cmsg_type);
fd = (*(int *)CMSG_DATA(cmsg));
if (debug)
fprintf(stderr, "%d: recv fd %d\n", getpid(), fd);
return fd;
}
static void usage(void) __attribute__((__noreturn__));
static void
usage(void)
{
fprintf(stderr, "Usage: %s [-vd] -i <input> -o <output>\n"
"\t %s [-v] -p <progname>\n", getprogname(), getprogname());
exit(EXIT_FAILURE);
}
int
main(int argc, char *argv[])
{
int s[2], fd, status, c, verbose;
char buf[1024], *prog;
prog = NULL;
s[0] = s[1] = -1;
verbose = 0;
while ((c = getopt(argc, argv, "di:o:p:")) != -1)
switch (c) {
case 'd':
debug++;
break;
case 'i':
s[0] = atoi(optarg);
break;
case 'o':
s[1] = atoi(optarg);
break;
case 'p':
prog = optarg;
break;
default:
usage();
}
if ((s[0] == -1 && s[1] != -1) || (s[0] != -1 && s[1] == -1))
usage();
if (s[0] == -1) {
if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, s) == -1)
err(1, "socketpair");
} else
goto recv;
switch (fork()) {
case -1:
err(1, "fork");
default:
fd = open("foo", O_RDWR|O_CREAT|O_TRUNC, 0666);
if (fd == -1)
err(1, "open");
send_fd(s[0], fd);
wait(&status);
return 0;
case 0:
if (prog != NULL) {
char i[64], o[64];
snprintf(i, sizeof(i), "%d", s[0]);
snprintf(o, sizeof(o), "%d", s[1]);
execlp(prog, prog, "-i", i, "-o", o, NULL);
err(1, "execlp");
}
recv:
fd = recv_fd(s[1]);
if (verbose) {
snprintf(buf, sizeof(buf), "ls -l /proc/%d/fd",
getpid());
system(buf);
}
if (write(fd, "foo\n", 4) == -1)
err(1, "write");
close(fd);
return 0;
}
}