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| | /* Fuzzing wrapper
* Derived from libnbd fuzzing wrapper
* Copyright (C) 2013-2022 Red Hat Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <poll.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <libnbd.h>
static void passt (int s);
static void qemu (int fd, int s);
int
main (int argc, char *argv[])
{
int fd;
pid_t pid;
int sv[2];
if (argc == 2) {
/* Open the test case before we fork so we know the file exists. */
fd = open (argv[1], O_RDONLY);
if (fd == -1) {
fprintf (stderr, "fuzz-wrapper: ");
perror (argv[1]);
exit (EXIT_FAILURE);
}
}
else {
fprintf (stderr, "fuzz-wrapper testcase\n");
exit (EXIT_FAILURE);
}
/* Create a connected socket. */
if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv) == -1) {
perror ("fuzz-wrapper: socketpair");
exit (EXIT_FAILURE);
}
/* Fork: The parent will be the passt process. The child will be
* the phony qemu.
*/
pid = fork ();
if (pid == -1) {
perror ("fuzz-wrapper: fork");
exit (EXIT_FAILURE);
}
if (pid > 0) {
/* Parent: passt. */
close (sv[1]);
close (fd);
passt (sv[0]);
}
/* Child: qemu. */
close (sv[0]);
qemu (fd, sv[1]);
close (sv[1]);
_exit (EXIT_SUCCESS);
}
/* This is the parent process running passt. */
static void
passt (int sock)
{
char sock_str[32];
snprintf (sock_str, sizeof sock_str, "%d", sock);
/* XXX Assumes passt is compiled in the top directory: */
execlp ("../passt", "passt", "-f", "-e", "-1", "--fd", sock_str, NULL);
perror ("fuzz-wrapper: execlp");
_exit (EXIT_FAILURE);
}
/* This is the child process acting like qemu. */
static void
qemu (int fd, int sock)
{
struct pollfd pfds[1];
char rbuf[512], wbuf[512];
size_t wsize = 0;
ssize_t r;
for (;;) {
pfds[0].fd = sock;
pfds[0].events = POLLIN;
if (wsize > 0 || fd >= 0) pfds[0].events |= POLLOUT;
pfds[0].revents = 0;
if (poll (pfds, 1, -1) == -1) {
if (errno == EINTR)
continue;
perror ("fuzz-wrapper: poll");
/* This is not an error. */
return;
}
/* We can read from the passt socket. Just throw away anything sent. */
if ((pfds[0].revents & POLLIN) != 0) {
r = read (sock, rbuf, sizeof rbuf);
if (r == -1 && errno != EINTR) {
perror ("fuzz-wrapper: read");
return;
}
else if (r == 0) /* end of input from the server */
return;
}
/* We can write to the passt socket. */
if ((pfds[0].revents & POLLOUT) != 0) {
/* Write more data from the wbuf. */
if (wsize > 0) {
morewrite:
r = write (sock, wbuf, wsize);
if (r == -1 && errno != EAGAIN && errno != EWOULDBLOCK) {
perror ("fuzz-wrapper: write");
return;
}
else if (r > 0) {
memmove (wbuf, &wbuf[r], wsize-r);
wsize -= r;
}
}
/* Write more data from the file. */
else if (fd >= 0) {
r = read (fd, wbuf, sizeof wbuf);
if (r == -1) {
perror ("fuzz-wrapper: read");
_exit (EXIT_FAILURE);
}
else if (r == 0) {
fd = -1; /* ignore the file from now on */
shutdown (sock, SHUT_WR);
}
else {
wsize = r;
goto morewrite;
}
}
}
} /* for (;;) */
}
|