minix/test/test76.c
David van Moolenbroek d95a36f6ae tests: add test76 for interrupting VFS operations
Change-Id: Ic436cac61de8c42e0c7ee2d442c647528654cde9
2014-02-18 11:25:03 +01:00

446 lines
10 KiB
C

/* Tests for interrupting VFS calls - by D.C. van Moolenbroek */
/* This test needs to be run as root; otherwise, openpty() won't work. */
#include <stdio.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include <netinet/in.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <util.h>
#define ITERATIONS 1
#include "common.h"
/*
* This signal handler does nothing. It just needs to be triggered, so that
* PM will tell VFS to unpause this process.
*/
static void dummy_handler(int sig)
{
/* Nothing. */
}
/*
* Interrupt a select(2) call.
*/
static void
test76a(void)
{
struct sigaction act, oact;
struct itimerval it;
struct sockaddr_in sin;
struct timeval tv;
fd_set set;
int tfd[2], pfd[2], sfd, maxfd;
subtest = 1;
act.sa_handler = dummy_handler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGALRM, &act, &oact) < 0) e(1);
memset(&it, 0, sizeof(it));
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 10000;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(2);
/* First try without any file descriptors. */
tv.tv_sec = 1;
tv.tv_usec = 0;
if (select(0, NULL, NULL, NULL, &tv) >= 0) e(3);
if (errno != EINTR) e(4);
/* Then try with different types of file descriptors, all blocking. */
if (openpty(&tfd[0], &tfd[1], NULL, NULL, NULL) < 0) e(5);
FD_ZERO(&set);
FD_SET(tfd[0], &set); /* reading from the PTY master should block */
maxfd = tfd[0];
if (pipe(pfd) < 0) e(6);
FD_SET(pfd[0], &set); /* reading from an empty pipe should block */
if (maxfd < pfd[0]) maxfd = pfd[0];
if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) e(7);
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
/* Binding to an arbitrary port is fine. */
if (bind(sfd, (struct sockaddr *)&sin, sizeof(sin)) < 0) e(8);
if (listen(sfd, 1) < 0) e(9);
FD_SET(sfd, &set); /* reading from a listening socket should block */
if (maxfd < sfd) maxfd = sfd;
memset(&it, 0, sizeof(it));
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 100000;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(10);
tv.tv_sec = 1;
tv.tv_usec = 0;
if (select(maxfd + 1, &set, NULL, NULL, &tv) >= 0) e(11);
if (errno != EINTR) e(12);
if (close(tfd[0]) < 0) e(13);
if (close(tfd[1]) < 0) e(14);
if (close(pfd[0]) < 0) e(15);
if (close(pfd[1]) < 0) e(16);
if (close(sfd) < 0) e(17);
if (sigaction(SIGUSR1, &oact, NULL) < 0) e(18);
}
/*
* Interrupt reads and writes to a pipe. POSIX states that if the operation
* was partially successful, the number of bytes written so far should be
* returned; otherwise, the we should get the normal EINTR.
*/
static void
test76b(void)
{
struct sigaction act, oact;
struct itimerval it;
char *buf;
int pfd[2];
subtest = 2;
if ((buf = malloc(PIPE_BUF * 2)) == NULL) e(1);
if (pipe(pfd) < 0) e(2);
act.sa_handler = dummy_handler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGALRM, &act, &oact) < 0) e(3);
memset(&it, 0, sizeof(it));
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 10000;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(4);
/*
* This write is too large for the pipe, so it will block until the
* signal arrives. When being interrupted, it should return the pipe
* size, as that is the part that has been filled successfully so far.
*/
if (write(pfd[1], buf, PIPE_BUF * 2) != PIPE_BUF) e(5);
/*
* Since the write partially succeeded, we should be able to read all
* we wrote so far, without blocking.
*/
if (read(pfd[0], buf, PIPE_BUF) != PIPE_BUF) e(6);
/* We should now be able to fill the pipe up to its full size again. */
if (write(pfd[1], buf, PIPE_BUF) != PIPE_BUF) e(7);
memset(&it, 0, sizeof(it));
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 10000;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(8);
/* Now interrupt a write attempt on a full pipe. */
if (write(pfd[1], buf, 1) >= 0) e(9);
if (errno != EINTR) e(10);
/* Empty the pipe again. */
if (read(pfd[0], buf, PIPE_BUF) != PIPE_BUF) e(11);
memset(&it, 0, sizeof(it));
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 10000;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(12);
/* Now interrupt a read on an empty pipe. */
if (read(pfd[0], buf, PIPE_BUF) >= 0) e(13);
if (errno != EINTR) e(14);
if (close(pfd[0]) < 0) e(15);
if (close(pfd[1]) < 0) e(16);
if (sigaction(SIGUSR1, &oact, NULL) < 0) e(17);
free(buf);
}
/*
* Interrupt an ioctl(2) call. We use an alarm to interrupt an accept(3) call
* on a TCP socket - the accept procedure is (currently) implemented using
* ioctl(2) calls.
*/
static void
test76c(void)
{
struct sigaction act, oact;
struct itimerval it;
struct sockaddr_in sin;
socklen_t len;
int sfd;
subtest = 3;
if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) e(1);
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
/* Binding to an arbitrary port is fine. */
if (bind(sfd, (struct sockaddr *)&sin, sizeof(sin)) < 0) e(2);
if (listen(sfd, 1) < 0) e(3);
act.sa_handler = dummy_handler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGALRM, &act, &oact) < 0) e(4);
memset(&it, 0, sizeof(it));
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 10000;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(5);
/* This will block until the timer fires. */
len = sizeof(sin);
if (accept(sfd, (struct sockaddr *)&sin, &len) >= 0) e(6);
if (errno != EINTR) e(7);
if (close(sfd) < 0) e(8);
if (sigaction(SIGUSR1, &oact, NULL) < 0) e(9);
}
/*
* Try to trigger semi-concurrent processing of normal system calls and
* postponed PM requests for a single process within VFS.
*/
static void
test76d(void)
{
struct utsname name;
struct sigaction act, oact;
struct itimerval it;
int r, fd, pfd[2], count, status;
time_t stime, etime, runtime = 30 /*seconds*/;
char buf[3], *pbuf;
subtest = 4;
/* This test would kill wimpy platforms such as ARM. */
if (uname(&name) < 0) e(1);
if (!strcmp(name.machine, "arm")) return;
act.sa_handler = dummy_handler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGALRM, &act, &oact) < 0) e(2);
if (pipe(pfd) < 0) e(3);
/* Pre-fill the pipe. */
if ((pbuf = malloc(PIPE_BUF - 1)) == NULL) e(4);
if (write(pfd[1], pbuf, PIPE_BUF - 1) != PIPE_BUF - 1) e(5);
free(pbuf);
switch (fork()) {
case 0:
if (close(pfd[1]) < 0) e(6);
/* Read from the pipe, but more slowly than the writer. */
while ((r = read(pfd[0], buf, 2)) != 0)
if (r < 0) e(7);
exit(0);
case -1:
e(8);
default:
break;
}
switch (fork()) {
case 0:
if (close(pfd[0]) < 0) e(9);
time(&stime);
/* Start an alarm mayhem. */
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 1;
it.it_interval.tv_sec = 0;
it.it_interval.tv_usec = 1;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(10);
/*
* Then start writing to the pipe, in such a way that the
* write operation will be suspended in every so many cases.
*/
do {
if (write(pfd[1], buf, 3) < 0 && errno != EINTR)
e(11);
time(&etime);
} while ((int)(etime - stime) < runtime);
exit(0);
case -1:
e(12);
default:
break;
}
if (close(pfd[0]) < 0) e(13);
if (close(pfd[1]) < 0) e(14);
/*
* First give the two processes a while to run regularly. Then start
* creating additional noise to keep the VFS worker threads busy.
*/
runtime /= 2;
sleep(runtime);
/*
* As of writing, VFS has less than 20 worker threads. Create more
* processes than that.
*/
for (count = 2; count < 20; count++) {
switch (fork()) {
case 0:
time(&stime);
do {
/*
* Opening a character device blocks the
* calling thread, hopefully causing work to be
* queued. Sadly, in practice, the high
* priorities of system processes prevent this
* case from occurring frequently. It works
* better with a driver that has a priority
* below that of of user processes.
*/
if ((fd = open("/dev/null", O_WRONLY)) < 0)
e(15);
close(fd);
time(&etime);
} while ((int)(etime - stime) < runtime);
exit(0);
case -1:
e(16);
default:
break;
}
}
/* Wait for all children to shut down. */
while (count-- > 0) {
if (wait(&status) <= 0) e(17);
if (!WIFEXITED(status)) e(18);
if (WEXITSTATUS(status) != 0) e(19);
}
if (sigaction(SIGUSR1, &oact, NULL) < 0) e(20);
}
/*
* Try to get a nonblocking select(2) call to be interrupted by a signal.
* In the future, VFS should prevent this from happening at all; for now, we
* just want to make sure it does not result in disaster when it does happen.
*/
static void
test76e(void)
{
struct utsname name;
struct sigaction act, oact;
struct itimerval it;
struct timeval tv;
fd_set set;
int tfd[2], left;
subtest = 5;
/* This test would kill wimpy platforms such as ARM. */
if (uname(&name) < 0) e(1);
if (!strcmp(name.machine, "arm")) return;
if (openpty(&tfd[0], &tfd[1], NULL, NULL, NULL) < 0) e(2);
act.sa_handler = dummy_handler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGALRM, &act, &oact) < 0) e(3);
/*
* Start an alarm mayhem. We have to try to get a signal in between
* VFS sending a select request to TTY, and TTY replying to VFS with
* initial results.
*/
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 1;
it.it_interval.tv_sec = 0;
it.it_interval.tv_usec = 1;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(4);
/*
* Now issue nonblocking selects until we get interrupted, or until
* we have gone through a hardcoded maximum of attempts.
*/
left = 100000;
do {
if (--left == 0) break;
FD_ZERO(&set);
FD_SET(tfd[0], &set); /* reading from master should block */
tv.tv_sec = 0;
tv.tv_usec = 0;
} while (select(2, &set, NULL, NULL, &tv) >= 0);
if (left > 0 && errno != EINTR) e(5);
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 0;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) e(6);
/* The call failed, so the set must be unmodified. */
if (left > 0 && !FD_SET(tfd[0], &set)) e(7);
if (close(tfd[0]) < 0) e(8);
if (close(tfd[1]) < 0) e(9);
if (sigaction(SIGUSR1, &oact, NULL) < 0) e(10);
}
int
main(int argc, char **argv)
{
int i, m;
start(76);
if (argc == 2)
m = atoi(argv[1]);
else
m = 0xFF;
for (i = 0; i < ITERATIONS; i++) {
if (m & 0x01) test76a();
if (m & 0x02) test76b();
if (m & 0x04) test76c();
if (m & 0x08) test76d();
if (m & 0x10) test76e();
}
quit();
}