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