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| | // SPDX-License-Identifier: GPL-2.0-or-later
// SPDX-FileCopyrightText: 2020-2021 Alyssa Ross <hi@alyssa.is>
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdnoreturn.h>
#include <string.h>
#include <sysexits.h>
#include <sys/socket.h>
#include <unistd.h>
#include <linux/vm_sockets.h>
#include "log.h"
#include "num.h"
#include "vsock.h"
noreturn static void ex_usage(void)
{
if (verbosity)
fprintf(stderr, "Usage: %s cid port prog...\n",
program_invocation_short_name);
exit(EX_USAGE);
}
int main(int argc, char *argv[])
{
int opt, fd;
uint32_t cid, port;
// A skeleton of an option parser to reject any options that
// are given, so we can add options in the future without
// worrying about breaking backwards compatibility because
// they were previously interpreted as a first argument.
while ((opt = getopt(argc, argv, "+")) != -1) {
switch (opt) {
default:
ex_usage();
}
}
// Check there are enough positional arguments (two for the
// address and at least one to exec into).
if (optind > argc - 3)
ex_usage();
// Parse the `cid' argument.
if (!strcmp(argv[optind], "-1"))
cid = VMADDR_CID_ANY;
else if (getu32(argv[optind], 0, UINT32_MAX, &cid))
ex_usage();
optind++;
// Parse the `port' argument.
if (!strcmp(argv[optind], "-1"))
port = VMADDR_PORT_ANY;
else if (getu32(argv[optind], 0, UINT32_MAX, &port))
ex_usage();
optind++;
// Set up the socket.
fd = socket(AF_VSOCK, SOCK_STREAM, 0);
if (fd == -1)
diee(EX_OSERR, "socket");
if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1)
diee(EX_OSERR, "fcntl");
if (vsock_bind(fd, cid, port) == -1)
diee(EX_OSERR, "bind");
if (listen(fd ,40) == -1)
diee(EX_OSERR, "listen");
// Place the socket at stdout.
if (dup2(fd, STDIN_FILENO) == -1)
diee(EX_OSERR, "dup2");
if (fd != STDIN_FILENO)
close(fd);
// Finally, exec into `prog'.
execvp(argv[optind], &argv[optind]);
diee(EX_OSERR, "execvp");
}
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