tests/clone.c

/* **********************************************************
 * Copyright (c) 2015 Google, Inc.  All rights reserved.
 * Copyright (c) 2009 VMware, Inc.  All rights reserved.
 * **********************************************************/

/* Dr. Memory: the memory debugger
 *
 * 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;
 * version 2.1 of the License, and no 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
 * Library 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.
 */

/* **********************************************************
 * Copyright (c) 2003-2008 VMware, Inc.  All rights reserved.
 * **********************************************************/

/*
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * * 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.
 *
 * * Neither the name of VMware, Inc. 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 COPYRIGHT HOLDERS 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 VMWARE, INC. 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.
 */

/* Largely identical to DynamoRIO's clone and thread tests.
 * Cleaned up some warnings.
 */

/*
 * test of clone call
 */

#include <sys/types.h> /* for wait and mmap */
#include <sys/wait.h>  /* for wait */
#include <time.h>      /* for nanosleep */
#include <sys/mman.h>  /* for mmap */
#include <assert.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>    /* memset */

#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>   /* For SYS_xxx definitions */

/* PR 426162: we want all 7 args to avoid non-deterministic UNINIT
 * and UNADDR from glibc passing uninit stack slots to syscall.
 * There's no way to use the sched.h defines w/o its clone() decl,
 * which takes only 4 args and ends up with uninit values to the other 3
 * SYS_clone params, so we have to duplicate the defines:
 */
#define CLONE_VM      0x00000100 /* Set if VM shared between processes.  */
#define CLONE_FS      0x00000200 /* Set if fs info shared between processes.  */
#define CLONE_FILES   0x00000400 /* Set if open files shared between processes.  */
#define CLONE_SIGHAND 0x00000800 /* Set if signal handlers shared.  */
extern int clone(int (*fn)(void *arg), void *child_stack,
                 int flags, void *arg,
                 pid_t *ptid, void *tls, pid_t *ctid);

/* with newer headers, these are in linux/sched.h, though not including anyway */
#define CLONE_THREAD	0x00010000	/* Same thread group? */
#define CLONE_CHILD_CLEARTID 0x00200000      /* clear the TID in the child */

#ifdef X86
# ifdef __i386__
#  define __NR_set_tid_address 258
#  define __NR_gettid 224
#  define __NR_exit 1
# else
#  define __NR_set_tid_address 218
#  define __NR_gettid 186
#  define __NR_exit 60
# endif
# define SYS_set_tid_address __NR_set_tid_address
# define SYS_gettid __NR_gettid
# define SYS_exit __NR_exit
#endif

#define false (0)
#define true (1)
typedef int bool;
#define THREAD_STACK_SIZE   (32*1024)

/* forward declarations */
static pid_t create_thread(int (*fcn)(void *), void *arg, void **stack);
static void delete_thread(pid_t pid, void *stack);
int run(void *arg);
static void* stack_alloc(int size);
static void stack_free(void *p, int size);

/* vars for child thread */
static pid_t child;
static void *stack;

/* these are used solely to provide deterministic output */
/* this is read by child, written by parent, tells child whether to exit */
static volatile bool child_exit;
/* this is read by parent, written by child, tells parent whether child done */
static volatile bool child_done;

static struct timespec sleeptime;

int main()
{
    sleeptime.tv_sec = 0;
    sleeptime.tv_nsec = 10*1000*1000; /* 10ms */

    child_exit = false;
    child_done = false;
    child = create_thread(run, NULL, &stack);
    assert(child > -1);

    /* waste some time */
    nanosleep(&sleeptime, NULL);

    child_exit = true;
    /* we want deterministic printf ordering */
    while (!child_done)
        nanosleep(&sleeptime, NULL);
    delete_thread(child, stack);

    return 0;
}

/* Procedure executed by sideline threads
 */
int run(void *arg)
{
    int i = 0;
    /* for CLONE_CHILD_CLEARTID for signaling parent.  if we used raw
     * clone system call we could get kernel to do this for us.
     * update: newer glibc takes in tidptr now
     */
    child = syscall(SYS_gettid);
    syscall(SYS_set_tid_address, &child);
    fprintf(stderr, "Sideline thread started\n");
    while (true) {
	/* do nothing for now */
	i++;
	if (i % 250000 == 0)
	    fprintf(stderr, "i = %d\n", i);
	if (i % 2500000 == 0)
	    break;
    }
    while (!child_exit)
        nanosleep(&sleeptime, NULL);
    fprintf(stderr, "Sideline thread finished\n");
    child_done = true;
#ifdef X64
    /* FIXME: returning here invokes SYS_exit_group and takes down the
     * parent...what's up with that?  Xref i#94.
     */
    syscall(SYS_exit);
#endif
    return 0;
}

/* Create a new thread. It should be passed "fcn", a function which
 * takes two arguments, (the second one is a dummy, always 4). The
 * first argument is passed in "arg". Returns the TID of the new
 * thread */
static pid_t
create_thread(int (*fcn)(void *), void *arg, void **stack)
{
    pid_t newpid;
    int flags;
    void *my_stack;

    my_stack = stack_alloc(THREAD_STACK_SIZE);
    /* need SIGCHLD so parent will get that signal when child dies,
     * else have errors doing a wait */
    flags = SIGCHLD | CLONE_THREAD | CLONE_VM |
        /* CLONE_THREAD => no signal to parent on termination; have to use
         * CLONE_CHILD_CLEARTID to get that.  Since we're using library call
         * instead of raw system call we don't have child_tidptr argument,
         * so we set the location in the child itself via set_tid_address(). */
        CLONE_CHILD_CLEARTID |
        CLONE_FS | CLONE_FILES | CLONE_SIGHAND;
    /* leaving args as NULL and set_tid_address() call in child since
     * don't feel like changing that code
     */
    newpid = clone(fcn, my_stack, flags, arg, NULL, NULL, NULL);
    /* this is really a tid since we passed CLONE_THREAD: child has same pid as us */

    if (newpid == -1) {
	fprintf(stderr, "smp.c: Error calling clone\n");
	stack_free(my_stack, THREAD_STACK_SIZE);
	return -1;
    }

    *stack = my_stack;
    return newpid;
}

static void
delete_thread(pid_t pid, void *stack)
{
    /* do not print out pids to make diff easy */
    fprintf(stderr, "Waiting for child to exit\n");
    /* pid is really a tid, and since we used CLONE_THREAD, we cannot use
     * any wait() routine since our parent has the child not us.
     * so we rely on CLONE_CHILD_CLEARTID.  FIXME: use futex here.
     * for now being really simple.
     */
    while (child != 0)
        nanosleep(&sleeptime, NULL);
    fprintf(stderr, "Child has exited\n");
    stack_free(stack, THREAD_STACK_SIZE);
}

/* allocate stack storage on the app's heap */
void*
stack_alloc(int size)
{
    size_t sp;
    void *q = NULL;
    void *p;

#if STACK_OVERFLOW_PROTECT
    /* allocate an extra page and mark it non-accessible to trap stack overflow */
    q = mmap(0, PAGE_SIZE, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
    assert(q);
    stack_redzone_start = (size_t) q;
#endif

    p = mmap(q, size, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
    assert(p);
#ifdef DEBUG
    memset(p, 0xab, size);
#endif

    /* stack grows from high to low addresses, so return a ptr to the top of the
       allocated region */
    sp = (size_t)p + size;

    return (void*) sp;
}

/* free memory-mapped stack storage */
void
stack_free(void *p, int size)
{
    size_t sp = (size_t)p - size;

    /* there was a memset of the stack here, which DrMem complained about
     * as unaddressable: xref PR 418629 where we do not un-mark, which I
     * think is the right thing to do (see comments there)
     */
    munmap((void *)sp, size);

#if STACK_OVERFLOW_PROTECT
    sp = sp - PAGE_SIZE;
    munmap((void*) sp, PAGE_SIZE);
#endif
}