/*
 *  File: stress.c
 *  Date: 16 November 1998
 *  Acct: David Powell (dep)
 *  Desc: Miscellaneous VM tests
 */

#include "mm.h"
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>

static void check_failed(const char *cmd)
{
    (void)printf("stress: %s failed: errno %d\n", cmd, errno);
    exit(1);
}

static int myfork()
{
    int result;

    result = fork();
    if (result == -1)
    {
        (void)printf("Fork failed (errno=%d)\n", errno);
        exit(1);
    }

    sched_yield();
    return result;
}

static void fork_test()
{
    (void)printf("-- Fork torture test start\n");

    (void)printf(
        "The final test: forking up a storm.\n"
        "If this doesn't crash your kernel, "
        "you might be in good shape\n");
    (void)printf("(note that this is running in the background)\n");
    if (!myfork())
    {
        for (;;)
        {
            if (myfork())
            {
                exit(0);
            }
        }
    }
}

static void cow_fork()
{
    int status;
    int foo = 0;

    (void)printf("-- COW fork test start\n");

    if (!myfork())
    {
        /* We are in the child process, and should be accessing
         * our own memory
         */
        foo = 1;
        exit(0);
    }

    if (wait(&status) == -1)
    {
        (void)printf("wait failed (errno=%d)\n", errno);
        exit(1);
    }

    if (foo)
    {
        (void)printf(
            "Data changed in child affected parent.\n"
            "Make sure you mark writable private mappings copy-on-write.\n");
        (void)printf("Copy-on-write failed.\n");
        exit(1);
    }

    (void)printf("-- COW fork test passed\n");
}

static void fault_test()
{
    int status;

    (void)printf("-- fault test start\n");

    (void)printf(
        "Fault test.  If this hangs, check your page fault handler...\n");
    (void)printf("Do you properly kill processes that segv?  ");

    if (!myfork())
    {
        *(int *)0 = 0;
        printf("P%d didn't fault!\n", getpid());
        exit(0);
    }

    if (wait(&status) == -1)
    {
        (void)printf("wait failed (errno=%d)\n", errno);
        exit(1);
    }
    if (status)
    {
        (void)printf("yes\n");
        ;
    }
    else
    {
        (void)printf("no\n");
        exit(1);
    }

    (void)printf("-- fault test passed\n");
}

void mmap_test()
{
    int fd;
    void *addr1, *addr2;
    const char *str1 = "Coconuts!!!!\n";
    const char *str2 = "Hello there.\n";
    size_t len;

    (void)printf("-- mmap test start\n");

    /* Create a file with some data. */

    fd = open("/test/stress0", O_RDWR | O_CREAT, 0);
    if (fd < 0)
    {
        check_failed("open");
    }

    /* Give us some space */
    if (1 > write(fd, "\0", 1))
    {
        check_failed("write");
    }

    /* Map the file MAP_PRIVATE */

    printf("MAP_PRIVATE test\n");
    len = strlen(str1) + 1;
    addr1 = mmap(0, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (addr1 == MAP_FAILED)
    {
        check_failed("mmap");
    }
    addr2 = mmap(0, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
    if (addr2 == MAP_FAILED)
    {
        check_failed("mmap");
    }

    if (close(fd))
    {
        check_failed("close");
    }

    printf("writing into %p\n", addr1);
    (void)snprintf((char *)addr1, len, "%s", str1);

    /* Read from the private mapped page for good measure
     * (this _shouldn't_ do anything) */
    printf("reading from privmap page\n");

    /* Verify that the string is initially in the mapping. */

    printf("making sure string in mapping okay\n");
    if (strcmp(str1, (char *)addr1))
    {
        (void)printf("stress: write to shared mapping failed\n");
        exit(1);
    }
    if (strcmp(str1, (char *)addr2))
    {
        (void)printf("stress: private mapping prematurely copied\n");
        exit(1);
    }

    (void)snprintf((char *)addr2, len, "%s", str2);

    /* Verify that the string has been overwritten in the mapping. */

    printf("making sure overwriting okay\n");
    if (strcmp(str2, (char *)addr2))
    {
        (void)printf("stress: write to private mapping failed\n");
        exit(1);
    }

    if (!strcmp(str2, (char *)addr1))
    {
        (void)printf("stress: wrote through private mapping!\n");
        exit(1);
    }

    printf("unmapping at %p\n", addr1);
    if (munmap(addr1, len))
    {
        check_failed("munmap");
    }
    printf("unmapping at %p\n", addr2);
    if (munmap(addr2, len))
    {
        check_failed("munmap");
    }

    if (!munmap((void *)USER_MEM_HIGH, 15) || (errno != EINVAL))
    {
        printf("munmap bad one fail errno=%d einval=%d\n", errno, EINVAL);
        exit(1);
    }

    if (!munmap(0, 0) || (errno != EINVAL))
    {
        printf("munmap bad two fail errno=%d einval=%d\n", errno, EINVAL);
        exit(1);
    }

    if (!munmap((void *)137, 100) || (errno != EINVAL))
    {
        printf("munmap bad three fail errno=%d einval=%d\n", errno, EINVAL);
        exit(1);
    }

    (void)printf("-- mmap test passed\n");
}

void null_test()
{
    int fd;
    int nbytes;
    char buf[256];

    (void)printf("-- null test start\n");

    fd = open("/dev/null", O_RDWR, 0600);
    if (fd < 0)
    {
        check_failed("open");
    }

    (void)memset(buf, 0xCC, sizeof(buf));

    /* Try writing to /dev/null.  Should return buffer size.
     */

    nbytes = write(fd, buf, sizeof(buf));
    if (nbytes != sizeof(buf))
    {
        check_failed("write");
    }

    /* Try reading from /dev/null.  Should return zero.
     */

    nbytes = read(fd, buf, sizeof(buf));
    if (nbytes != 0)
    {
        check_failed("read");
    }

    if (close(fd))
    {
        check_failed("close");
    }

    (void)printf("-- null test passed\n");
}

void zero_test()
{
    void *addr;
    int fd;
    char buf[256];
    int nbytes;
    unsigned int ii;
    size_t len;
    unsigned long *lp;
    unsigned char *cp;

    (void)printf("-- zero test start\n");

    fd = open("/dev/zero", O_RDWR, 0600);
    if (fd < 0)
    {
        check_failed("open");
    }

    /* Set buffer to a non-zero value, then read from /dev/zero
     * and make sure that the buffer is cleared.
     */

    memset(buf, 0xCC, sizeof(buf));

    nbytes = read(fd, buf, sizeof(buf));
    if (nbytes != sizeof(buf))
    {
        check_failed("read");
    }

    for (ii = 0; ii < sizeof(buf); ii++)
    {
        if (buf[ii] != 0)
        {
            printf("read %x not zero\n", buf[ii]);
            check_failed("verify read");
        }
    }

    /* Map /dev/zero and make sure all pages are initially zero.
     */

    len = 8192 * 5;

    addr = mmap(0, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
    if (addr == MAP_FAILED)
    {
        check_failed("mmap");
    }

    if (close(fd))
    {
        check_failed("close");
    }

    cp = (unsigned char *)addr;
    for (ii = 0; ii < len; ii++, cp++)
    {
        if (*cp != 0)
        {
            check_failed("verify mmap zeros");
        }
    }

    /* ... make sure writes are allowed.
     */

    lp = (unsigned long *)addr;
    for (ii = 0; ii < (len / sizeof(*lp)); ii++, lp++)
    {
        *lp = ii;
    }

    lp = (unsigned long *)addr;
    for (ii = 0; ii < (len / sizeof(*lp)); ii++, lp++)
    {
        if (*lp != ii)
        {
            check_failed("verify map write");
        }
    }

    if (munmap(addr, len))
    {
        check_failed("munmap");
    }

    (void)printf("-- zero test passed\n");
}

void wait_test()
{
    int status;

    (void)printf("-- wait test start\n");

    if (!wait(&status) || (errno != ECHILD))
    {
        (void)printf(
            "error: wait() didn't return an error of "
            "ECHILD when no children existed!\n");
        exit(1);
    }

    (void)printf("-- wait test passed\n");
}

void brk_test()
{
    void *oldbrk1, *oldbrk2;
    const void *brk_failed = (void *)-1;
    int len;
    unsigned int *tmp;
    unsigned int ii;

    (void)printf("-- brk test start\n");

    /* A length which is not a page multiple, yet a multiple of 8.
     */
    len = 8192 * 5 + 128;

    /* Try allocating some memory.
     */
    oldbrk1 = sbrk(len);
    if (oldbrk1 == brk_failed)
    {
        check_failed("sbrk alloc");
    }

    /* Try writing to the memory.
     */
    printf("writing to memory at %p\n", oldbrk1);
    tmp = (unsigned int *)oldbrk1;
    for (ii = 0; ii < (len / sizeof(int)); ii++)
    {
        *tmp++ = ii;
    }

    /* Try verifying what we wrote.
     */
    printf("verifying memory\n");
    tmp = (unsigned int *)oldbrk1;
    for (ii = 0; ii < (len / sizeof(int)); ii++)
    {
        if (*tmp++ != ii)
        {
            (void)printf("verify failed at 0x%lx\n", (unsigned long)tmp);
            exit(1);
        }
    }

    /* Try freeing the memory.
     */
    printf("freeing memory\n");
    oldbrk2 = sbrk(-len);
    if (oldbrk2 == brk_failed)
    {
        check_failed("sbrk dealloc");
    }

    /* oldbrk2 should be at least "len" greater than oldbrk1.
     */
    if ((unsigned long)oldbrk2 < ((unsigned long)oldbrk1 + len))
    {
        (void)printf("sbrk didn't return old brk??\n");
        exit(1);
    }

    (void)printf("-- brk test passed\n");
}

int main(int argc, char **argv)
{
    (void)printf("Congrats!  You're running this executable.\n");
    (void)printf("Now let's see how you handle the tests...\n");

    mmap_test();

    null_test();
    zero_test();
    brk_test();

    fault_test();

    wait_test();
    cow_fork();

    fork_test();

    return 0;
}