bad_waitpid.c

/*
 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
 *      The President and Fellows of Harvard College.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``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 UNIVERSITY OR CONTRIBUTORS 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.
 */

/*
 * bad calls to waitpid()
 */

#include <sys/types.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <err.h>

#include "config.h"
#include "test.h"

static
void
wait_badpid(int pid, const char *desc)
{
        int rv, x;
        rv = waitpid(pid, &x, 0);
        report_test2(rv, errno, EINVAL, NOSUCHPID_ERROR, desc);
}

static
void
wait_badstatus(void *ptr, const char *desc)
{
        int rv, pid, x;

        pid = fork();
        if (pid<0) {
                warn("UH-OH: fork failed");
                return;
        }
        if (pid==0) {
                exit(0);
        }

        rv = waitpid(pid, ptr, 0);
        report_test(rv, errno, EFAULT, desc);
        waitpid(pid, &x, 0);
}

static
void
wait_unaligned(void)
{
        int rv, pid, x;
        int status[2];  /* will have integer alignment */
        char *ptr;

        pid = fork();
        if (pid<0) {
                warn("UH-OH: fork failed");
                return;
        }
        if (pid==0) {
                exit(0);
        }

        /* start with proper integer alignment */
        ptr = (char *)(&status[0]);

        /* generate improper alignment on platforms with restrictions*/
        ptr++;

        rv = waitpid(pid, (int *)ptr, 0);
        report_survival(rv, errno, "wait with unaligned status");
        if (rv<0) {
                waitpid(pid, &x, 0);
        }
}

static
void
wait_badflags(void)
{
        int rv, x, pid;

        pid = fork();
        if (pid<0) {
                warn("UH-OH: fork failed");
                return;
        }
        if (pid==0) {
                exit(0);
        }

        rv = waitpid(pid, &x, 309429);
        report_test(rv, errno, EINVAL, "wait with bad flags");
        waitpid(pid, &x, 0);
}

static
void
wait_self(void)
{
        int rv, x;
        rv = waitpid(getpid(), &x, 0);
        report_survival(rv, errno, "wait for self");
}

static
void
wait_parent(void)
{
        int mypid, childpid, rv, x;

        mypid = getpid();
        childpid = fork();
        if (childpid<0) {
                warn("UH-OH: can't fork");
                return;
        }
        if (childpid==0) {
                /* Child. Wait for parent. */
                rv = waitpid(mypid, &x, 0);
                report_survival(rv, errno, "wait for parent (from child)");
                _exit(0);
        }
        rv = waitpid(childpid, &x, 0);
        report_survival(rv, errno, "wait for parent test (from parent)");
}

////////////////////////////////////////////////////////////

static
void
wait_siblings_child(void)
{
        int pids[2], mypid, otherpid, fd, rv, x;

        mypid = getpid();

        fd = open(TESTFILE, O_RDONLY);
        if (fd<0) {
                warn("UH-OH: child process (pid %d) can't open %s",
                     mypid, TESTFILE);
                return;
        }

        /*
         * Busy-wait until the parent writes the pids into the file.
         * This sucks, but there's not a whole lot else we can do.
         */
        do {
                rv = lseek(fd, 0, SEEK_SET);
                if (rv<0) {
                        warn("UH-OH: child process (pid %d) lseek error",
                             mypid);
                        return;
                }
                rv = read(fd, pids, sizeof(pids));
                if (rv<0) {
                        warn("UH-OH: child process (pid %d) read error",
                             mypid);
                        return;
                }
        } while (rv < (int)sizeof(pids));

        if (mypid==pids[0]) {
                otherpid = pids[1];
        }
        else if (mypid==pids[1]) {
                otherpid = pids[0];
        }
        else {
                warn("UH-OH: child process (pid %d) got garbage in comm file",
                     mypid);
                return;
        }
        close(fd);

        rv = waitpid(otherpid, &x, 0);
        report_survival(rv, errno, "sibling wait");
}

static
void
wait_siblings(void)
{
        int pids[2], fd, rv, x;

        /* Note: this may also blow up if FS synchronization is substandard */

        fd = open_testfile(NULL);
        if (fd<0) {
                return;
        }

        pids[0] = fork();
        if (pids[0]<0) {
                warn("UH-OH: can't fork");
                return;
        }
        if (pids[0]==0) {
                close(fd);
                wait_siblings_child();
                _exit(0);
        }

        pids[1] = fork();
        if (pids[1]<0) {
                warn("UH-OH: can't fork");
                /* abandon the other child process :( */
                return;
        }
        if (pids[1]==0) {
                close(fd);
                wait_siblings_child();
                _exit(0);
        }

        rv = write(fd, pids, sizeof(pids));
        if (rv < 0) {
                warn("UH-OH: write error on %s", TESTFILE);
                /* abandon child procs :( */
                return;
        }
        if (rv != (int)sizeof(pids)) {
                warnx("UH-OH: write error on %s: short count", TESTFILE);
                /* abandon child procs :( */
                return;
        }

        rv = waitpid(pids[0], &x, 0);
        if (rv<0) {
                warn("UH-OH: error waiting for child 0 (pid %d)", pids[0]);
        }
        rv = waitpid(pids[1], &x, 0);
        if (rv<0) {
                warn("UH-OH: error waiting for child 1 (pid %d)", pids[1]);
        }
        warnx("passed: siblings wait for each other");
        close(fd);
        remove(TESTFILE);
}

////////////////////////////////////////////////////////////

void
test_waitpid(void)
{
        wait_badpid(-8, "wait for pid -8");
        wait_badpid(-1, "wait for pid -1");
        wait_badpid(0, "pid zero");
        wait_badpid(NONEXIST_PID, "nonexistent pid");

        wait_badstatus(NULL, "wait with NULL status");
        wait_badstatus(INVAL_PTR, "wait with invalid pointer status");
        wait_badstatus(KERN_PTR, "wait with kernel pointer status");

        wait_unaligned();

        wait_badflags();

        wait_self();
        wait_parent();
        wait_siblings();
}