kernel: some boottime sanitychecks

[minix.git] / test / blocktest / blocktest.c

/* Block Device Driver Test driver, by D.C. van Moolenbroek */
#include <stdlib.h>
#include <minix/blockdriver.h>
#include <minix/drvlib.h>
#include <minix/ds.h>
#include <minix/optset.h>
#include <sys/ioc_disk.h>
#include <assert.h>

enum {
        RESULT_OK,                      /* exactly as expected */
        RESULT_DEATH,                   /* driver died */
        RESULT_COMMFAIL,                /* communication failed */
        RESULT_BADTYPE,                 /* bad type in message */
        RESULT_BADID,                   /* bad request ID in message */
        RESULT_BADSTATUS,               /* bad/unexpected status in message */
        RESULT_TRUNC,                   /* request truncated unexpectedly */
        RESULT_CORRUPT,                 /* buffer touched erroneously */
        RESULT_MISSING,                 /* buffer left untouched erroneously */
        RESULT_OVERFLOW,                /* area around buffer touched */
        RESULT_BADVALUE                 /* bad/unexpected return value */
};

typedef struct {
        int type;
        ssize_t value;
} result_t;

static char driver_label[32] = "";      /* driver DS label */
static dev_t driver_minor = -1; /* driver's partition minor to use */
static endpoint_t driver_endpt; /* driver endpoint */

static int may_write = FALSE;           /* may we write to the device? */
static int sector_size = 512;           /* size of a single disk sector */
static int min_read = 512;              /* minimum total size of read req */
static int element_size = 512;          /* minimum I/O vector element size */
static int max_size = 131072;           /* maximum total size of any req */
/* Note that we do not test exceeding the max_size limit, so it is safe to set
 * it to a value lower than the driver supports.
 */

static struct partition part;           /* base and size of target partition */

#define NR_OPENED 10                    /* maximum number of opened devices */
static dev_t opened[NR_OPENED]; /* list of currently opened devices */
static int nr_opened = 0;               /* current number of opened devices */

static int total_tests = 0;             /* total number of tests performed */
static int failed_tests = 0;            /* number of tests that failed */
static int failed_groups = 0;           /* nr of groups that had failures */
static int group_failure;               /* has this group had a failure yet? */
static int driver_deaths = 0;           /* number of restarts that we saw */

/* Options supported by this driver. */
static struct optset optset_table[] = {
        { "label",      OPT_STRING,     driver_label,   sizeof(driver_label) },
        { "minor",      OPT_INT,        &driver_minor,  10                   },
        { "rw",         OPT_BOOL,       &may_write,     TRUE                 },
        { "ro",         OPT_BOOL,       &may_write,     FALSE                },
        { "sector",     OPT_INT,        &sector_size,   10                   },
        { "element",    OPT_INT,        &element_size,  10                   },
        { "min_read",   OPT_INT,        &min_read,      10                   },
        { "max",        OPT_INT,        &max_size,      10                   },
        { NULL,         0,              NULL,           0                    }
};

static int set_result(result_t *res, int type, ssize_t value)
{
        /* Set the result to the given result type and with the given optional
         * extra value. Return the type.
         */
        res->type = type;
        res->value = value;

        return type;
}

static int accept_result(result_t *res, int type, ssize_t value)
{
        /* If the result is of the given type and value, reset it to a success
         * result. This allows for a logical OR on error codes. Return whether
         * the result was indeed reset.
         */

        if (res->type == type && res->value == value) {
                set_result(res, RESULT_OK, 0);

                return TRUE;
        }

        return FALSE;
}

static void got_result(result_t *res, char *desc)
{
        /* Process the result of a test. Keep statistics.
         */
        static int i = 0;

        total_tests++;
        if (res->type != RESULT_OK) {
                failed_tests++;

                if (group_failure == FALSE) {
                        failed_groups++;
                        group_failure = TRUE;
                }
        }

        printf("#%02d: %-38s\t[%s]\n", ++i, desc,
                (res->type == RESULT_OK) ? "PASS" : "FAIL");

        switch (res->type) {
        case RESULT_DEATH:
                printf("- driver died\n");
                break;
        case RESULT_COMMFAIL:
                printf("- communication failed; sendrec returned %d\n",
                        res->value);
                break;
        case RESULT_BADTYPE:
                printf("- bad type %d in reply message\n", res->value);
                break;
        case RESULT_BADID:
                printf("- mismatched ID %d in reply message\n", res->value);
                break;
        case RESULT_BADSTATUS:
                printf("- bad or unexpected status %d in reply message\n",
                        res->value);
                break;
        case RESULT_TRUNC:
                printf("- result size not as expected (%u bytes left)\n",
                        res->value);
                break;
        case RESULT_CORRUPT:
                printf("- buffer has been modified erroneously\n");
                break;
        case RESULT_MISSING:
                printf("- buffer has been left untouched erroneously\n");
                break;
        case RESULT_OVERFLOW:
                printf("- area around target buffer modified\n");
                break;
        case RESULT_BADVALUE:
                printf("- bad or unexpected return value %d from call\n",
                        res->value);
                break;
        }
}

static void test_group(char *name, int exec)
{
        /* Start a new group of tests.
         */

        printf("Test group: %s%s\n", name, exec ? "" : " (skipping)");

        group_failure = FALSE;
}

static void reopen_device(dev_t minor)
{
        /* Reopen a device after we were notified that the driver has died.
         * Explicitly ignore any errors here; this is a feeble attempt to get
         * ourselves back into business again.
         */
        message m;

        memset(&m, 0, sizeof(m));
        m.m_type = BDEV_OPEN;
        m.BDEV_MINOR = minor;
        m.BDEV_ACCESS = (may_write) ? (R_BIT | W_BIT) : R_BIT;
        m.BDEV_ID = 0;

        (void) sendrec(driver_endpt, &m);
}

static int sendrec_driver(message *m_ptr, ssize_t exp, result_t *res)
{
        /* Make a call to the driver, and perform basic checks on the return
         * message. Fill in the result structure, wiping out what was in there
         * before. If the driver dies in the process, attempt to recover but
         * fail the request.
         */
        message m_orig;
        endpoint_t last_endpt;
        int i, r;

        m_orig = *m_ptr;

        r = sendrec(driver_endpt, m_ptr);

        if (r == EDEADSRCDST) {
                /* The driver has died. Find its new endpoint, and reopen all
                 * devices that we opened earlier. Then return failure.
                 */
                printf("WARNING: driver has died, attempting to proceed\n");

                driver_deaths++;

                /* Keep trying until we get a new endpoint. */
                last_endpt = driver_endpt;
                for (;;) {
                        r = ds_retrieve_label_endpt(driver_label,
                                &driver_endpt);

                        if (r == OK && last_endpt != driver_endpt)
                                break;

                        micro_delay(100000);
                }

                for (i = 0; i < nr_opened; i++)
                        reopen_device(opened[i]);

                return set_result(res, RESULT_DEATH, 0);
        }

        if (r != OK)
                return set_result(res, RESULT_COMMFAIL, r);

        if (m_ptr->m_type != BDEV_REPLY)
                return set_result(res, RESULT_BADTYPE, m_ptr->m_type);

        if (m_ptr->BDEV_ID != m_orig.BDEV_ID)
                return set_result(res, RESULT_BADID, m_ptr->BDEV_ID);

        if ((exp < 0 && m_ptr->BDEV_STATUS >= 0) ||
                        (exp >= 0 && m_ptr->BDEV_STATUS < 0))
                return set_result(res, RESULT_BADSTATUS, m_ptr->BDEV_STATUS);

        return set_result(res, RESULT_OK, 0);
}

static void raw_xfer(dev_t minor, u64_t pos, iovec_s_t *iovec, int nr_req,
        int write, ssize_t exp, result_t *res)
{
        /* Perform a transfer with a safecopy iovec already supplied.
         */
        cp_grant_id_t grant;
        message m;
        int r;

        assert(nr_req <= NR_IOREQS);
        assert(!write || may_write);

        if ((grant = cpf_grant_direct(driver_endpt, (vir_bytes) iovec,
                        sizeof(*iovec) * nr_req, CPF_READ)) == GRANT_INVALID)
                panic("unable to allocate grant");

        memset(&m, 0, sizeof(m));
        m.m_type = write ? BDEV_SCATTER : BDEV_GATHER;
        m.BDEV_MINOR = minor;
        m.BDEV_POS_LO = ex64lo(pos);
        m.BDEV_POS_HI = ex64hi(pos);
        m.BDEV_COUNT = nr_req;
        m.BDEV_GRANT = grant;
        m.BDEV_ID = lrand48();

        r = sendrec_driver(&m, exp, res);

        if (cpf_revoke(grant) != OK)
                panic("unable to revoke grant");

        if (r != RESULT_OK)
                return;

        if (m.BDEV_STATUS == exp)
                return;

        if (exp < 0)
                set_result(res, RESULT_BADSTATUS, m.BDEV_STATUS);
        else
                set_result(res, RESULT_TRUNC, exp - m.BDEV_STATUS);
}

static void vir_xfer(dev_t minor, u64_t pos, iovec_t *iovec, int nr_req,
        int write, ssize_t exp, result_t *res)
{
        /* Perform a transfer, creating and revoking grants for the I/O vector.
         */
        iovec_s_t iov_s[NR_IOREQS];
        int i;

        assert(nr_req <= NR_IOREQS);

        for (i = 0; i < nr_req; i++) {
                iov_s[i].iov_size = iovec[i].iov_size;

                if ((iov_s[i].iov_grant = cpf_grant_direct(driver_endpt,
                        (vir_bytes) iovec[i].iov_addr, iovec[i].iov_size,
                        write ? CPF_READ : CPF_WRITE)) == GRANT_INVALID)
                        panic("unable to allocate grant");
        }

        raw_xfer(minor, pos, iov_s, nr_req, write, exp, res);

        for (i = 0; i < nr_req; i++) {
                iovec[i].iov_size = iov_s[i].iov_size;

                if (cpf_revoke(iov_s[i].iov_grant) != OK)
                        panic("unable to revoke grant");
        }
}

static void simple_xfer(dev_t minor, u64_t pos, u8_t *buf, size_t size,
        int write, ssize_t exp, result_t *res)
{
        /* Perform a transfer involving a single buffer.
         */
        iovec_t iov;

        iov.iov_addr = (vir_bytes) buf;
        iov.iov_size = size;

        vir_xfer(minor, pos, &iov, 1, write, exp, res);
}

static void alloc_buf_and_grant(u8_t **ptr, cp_grant_id_t *grant,
        size_t size, int perms)
{
        /* Allocate a buffer suitable for DMA (i.e. contiguous) and create a
         * grant for it with the requested CPF_* grant permissions.
         */

        *ptr = alloc_contig(size, 0, NULL);
        if (*ptr == NULL)
                panic("unable to allocate memory");

        if ((*grant = cpf_grant_direct(driver_endpt, (vir_bytes) *ptr, size,
                        perms)) == GRANT_INVALID)
                panic("unable to allocate grant");
}

static void free_buf_and_grant(u8_t *ptr, cp_grant_id_t grant, size_t size)
{
        /* Revoke a grant and free a buffer.
         */

        cpf_revoke(grant);

        free_contig(ptr, size);
}

static void bad_read1(void)
{
        /* Test various illegal read transfer requests, part 1.
         */
        message mt, m;
        iovec_s_t iovt, iov;
        cp_grant_id_t grant, grant2, grant3;
        u8_t *buf_ptr;
        vir_bytes buf_size;
        result_t res;

        test_group("bad read requests, part one", TRUE);

#define BUF_SIZE        4096
        buf_size = BUF_SIZE;

        alloc_buf_and_grant(&buf_ptr, &grant2, buf_size, CPF_WRITE);

        if ((grant = cpf_grant_direct(driver_endpt, (vir_bytes) &iov,
                        sizeof(iov), CPF_READ)) == GRANT_INVALID)
                panic("unable to allocate grant");

        /* Initialize the defaults for some of the tests.
         * This is a legitimate request for the first block of the partition.
         */
        memset(&mt, 0, sizeof(mt));
        mt.m_type = BDEV_GATHER;
        mt.BDEV_MINOR = driver_minor;
        mt.BDEV_POS_LO = 0L;
        mt.BDEV_POS_HI = 0L;
        mt.BDEV_COUNT = 1;
        mt.BDEV_GRANT = grant;
        mt.BDEV_ID = lrand48();

        memset(&iovt, 0, sizeof(iovt));
        iovt.iov_grant = grant2;
        iovt.iov_size = buf_size;

        /* Test normal request. */
        m = mt;
        iov = iovt;

        sendrec_driver(&m, OK, &res);

        if (res.type == RESULT_OK && m.BDEV_STATUS != (ssize_t) iov.iov_size) {
                res.type = RESULT_TRUNC;
                res.value = m.BDEV_STATUS;
        }

        got_result(&res, "normal request");

        /* Test zero iovec elements. */
        m = mt;
        iov = iovt;

        m.BDEV_COUNT = 0;

        sendrec_driver(&m, EINVAL, &res);

        got_result(&res, "zero iovec elements");

        /* Test bad iovec grant. */
        m = mt;

        m.BDEV_GRANT = GRANT_INVALID;

        sendrec_driver(&m, EINVAL, &res);

        got_result(&res, "bad iovec grant");

        /* Test revoked iovec grant. */
        m = mt;
        iov = iovt;

        if ((grant3 = cpf_grant_direct(driver_endpt, (vir_bytes) &iov,
                        sizeof(iov), CPF_READ)) == GRANT_INVALID)
                panic("unable to allocate grant");

        cpf_revoke(grant3);

        m.BDEV_GRANT = grant3;

        sendrec_driver(&m, EINVAL, &res);

        accept_result(&res, RESULT_BADSTATUS, EPERM);

        got_result(&res, "revoked iovec grant");

        /* Test normal request (final check). */
        m = mt;
        iov = iovt;

        sendrec_driver(&m, OK, &res);

        if (res.type == RESULT_OK && m.BDEV_STATUS != (ssize_t) iov.iov_size) {
                res.type = RESULT_TRUNC;
                res.value = m.BDEV_STATUS;
        }

        got_result(&res, "normal request");

        /* Clean up. */
        free_buf_and_grant(buf_ptr, grant2, buf_size);

        cpf_revoke(grant);
}

static u32_t get_sum(u8_t *ptr, size_t size)
{
        /* Compute a checksum over the given buffer.
         */
        u32_t sum;

        for (sum = 0; size > 0; size--, ptr++)
                sum = sum ^ (sum << 5) ^ *ptr;

        return sum;
}

static u32_t fill_rand(u8_t *ptr, size_t size)
{
        /* Fill the given buffer with random data. Return a checksum over the
         * resulting data.
         */
        size_t i;

        for (i = 0; i < size; i++)
                ptr[i] = lrand48() % 256;

        return get_sum(ptr, size);
}

static void test_sum(u8_t *ptr, size_t size, u32_t sum, int should_match,
        result_t *res)
{
        /* If the test succeeded so far, check whether the given buffer does
         * or does not match the given checksum, and adjust the test result
         * accordingly.
         */
        u32_t sum2;

        if (res->type != RESULT_OK)
                return;

        sum2 = get_sum(ptr, size);

        if ((sum == sum2) != should_match) {
                res->type = should_match ? RESULT_CORRUPT : RESULT_MISSING;
                res->value = 0;         /* not much that's useful here */
        }
}

static void bad_read2(void)
{
        /* Test various illegal read transfer requests, part 2.
         *
         * Consider allowing this test to be run twice, with different buffer
         * sizes. It appears that we can make at_wini misbehave by making the
         * size exceed the per-operation size (128KB ?). On the other hand, we
         * then need to start checking partition sizes, possibly.
         */
        u8_t *buf_ptr, *buf2_ptr, *buf3_ptr, c1, c2;
        size_t buf_size, buf2_size, buf3_size;
        cp_grant_id_t buf_grant, buf2_grant, buf3_grant, grant;
        u32_t buf_sum, buf2_sum, buf3_sum;
        iovec_s_t iov[3], iovt[3];
        result_t res;

        test_group("bad read requests, part two", TRUE);

        buf_size = buf2_size = buf3_size = BUF_SIZE;

        alloc_buf_and_grant(&buf_ptr, &buf_grant, buf_size, CPF_WRITE);
        alloc_buf_and_grant(&buf2_ptr, &buf2_grant, buf2_size, CPF_WRITE);
        alloc_buf_and_grant(&buf3_ptr, &buf3_grant, buf3_size, CPF_WRITE);

        iovt[0].iov_grant = buf_grant;
        iovt[0].iov_size = buf_size;
        iovt[1].iov_grant = buf2_grant;
        iovt[1].iov_size = buf2_size;
        iovt[2].iov_grant = buf3_grant;
        iovt[2].iov_size = buf3_size;

        /* Test normal vector request. */
        memcpy(iov, iovt, sizeof(iovt));

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE,
                buf_size + buf2_size + buf3_size, &res);

        test_sum(buf_ptr, buf_size, buf_sum, FALSE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, FALSE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, FALSE, &res);

        got_result(&res, "normal vector request");

        /* Test zero sized iovec element. */
        memcpy(iov, iovt, sizeof(iovt));
        iov[1].iov_size = 0;

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, EINVAL, &res);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "zero size in iovec element");

        /* Test negative sized iovec element. */
        memcpy(iov, iovt, sizeof(iovt));
        iov[1].iov_size = (vir_bytes) LONG_MAX + 1;

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, EINVAL, &res);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "negative size in iovec element");

        /* Test iovec with negative total size. */
        memcpy(iov, iovt, sizeof(iovt));
        iov[0].iov_size = LONG_MAX / 2 - 1;
        iov[1].iov_size = LONG_MAX / 2 - 1;

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, EINVAL, &res);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "negative total size");

        /* Test iovec with wrapping total size. */
        memcpy(iov, iovt, sizeof(iovt));
        iov[0].iov_size = LONG_MAX - 1;
        iov[1].iov_size = LONG_MAX - 1;

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, EINVAL, &res);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "wrapping total size");

        /* Test word-unaligned iovec element size. */
        memcpy(iov, iovt, sizeof(iovt));
        iov[1].iov_size--;

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);
        c1 = buf2_ptr[buf2_size - 1];

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, BUF_SIZE * 3 - 1,
                &res);

        if (accept_result(&res, RESULT_BADSTATUS, EINVAL)) {
                /* Do not test the first buffer, as it may contain a partial
                 * result.
                 */
                test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
                test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);
        } else {
                test_sum(buf_ptr, buf_size, buf_sum, FALSE, &res);
                test_sum(buf2_ptr, buf2_size, buf2_sum, FALSE, &res);
                test_sum(buf3_ptr, buf3_size, buf3_sum, FALSE, &res);
                if (c1 != buf2_ptr[buf2_size - 1])
                        set_result(&res, RESULT_CORRUPT, 0);
        }

        got_result(&res, "word-unaligned size in iovec element");

        /* Test invalid grant in iovec element. */
        memcpy(iov, iovt, sizeof(iovt));
        iov[1].iov_grant = GRANT_INVALID;

        fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, EINVAL, &res);

        /* Do not test the first buffer, as it may contain a partial result. */
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "invalid grant in iovec element");

        /* Test revoked grant in iovec element. */
        memcpy(iov, iovt, sizeof(iovt));
        if ((grant = cpf_grant_direct(driver_endpt, (vir_bytes) buf2_ptr,
                        buf2_size, CPF_WRITE)) == GRANT_INVALID)
                panic("unable to allocate grant");

        cpf_revoke(grant);

        iov[1].iov_grant = grant;

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, EINVAL, &res);

        accept_result(&res, RESULT_BADSTATUS, EPERM);

        /* Do not test the first buffer, as it may contain a partial result. */
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "revoked grant in iovec element");

        /* Test read-only grant in iovec element. */
        memcpy(iov, iovt, sizeof(iovt));
        if ((grant = cpf_grant_direct(driver_endpt, (vir_bytes) buf2_ptr,
                        buf2_size, CPF_READ)) == GRANT_INVALID)
                panic("unable to allocate grant");

        iov[1].iov_grant = grant;

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, EINVAL, &res);

        accept_result(&res, RESULT_BADSTATUS, EPERM);

        /* Do not test the first buffer, as it may contain a partial result. */
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "read-only grant in iovec element");

        cpf_revoke(grant);

        /* Test word-unaligned iovec element buffer. */
        memcpy(iov, iovt, sizeof(iovt));
        if ((grant = cpf_grant_direct(driver_endpt, (vir_bytes) (buf2_ptr + 1),
                        buf2_size - 2, CPF_WRITE)) == GRANT_INVALID)
                panic("unable to allocate grant");

        iov[1].iov_grant = grant;
        iov[1].iov_size = buf2_size - 2;

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);
        c1 = buf2_ptr[0];
        c2 = buf2_ptr[buf2_size - 1];

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE, BUF_SIZE * 3 - 2,
                &res);

        if (accept_result(&res, RESULT_BADSTATUS, EINVAL)) {
                /* Do not test the first buffer, as it may contain a partial
                 * result.
                 */
                test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
                test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);
        } else {
                test_sum(buf_ptr, buf_size, buf_sum, FALSE, &res);
                test_sum(buf2_ptr, buf2_size, buf2_sum, FALSE, &res);
                test_sum(buf3_ptr, buf3_size, buf3_sum, FALSE, &res);
                if (c1 != buf2_ptr[0] || c2 != buf2_ptr[buf2_size - 1])
                        set_result(&res, RESULT_CORRUPT, 0);
        }

        got_result(&res, "word-unaligned buffer in iovec element");

        cpf_revoke(grant);

        /* Test word-unaligned position. */
        memcpy(iov, iovt, sizeof(iovt));

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(1), iov, 3, FALSE, EINVAL, &res);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "word-unaligned position");

        /* Test normal vector request (final check). */
        memcpy(iov, iovt, sizeof(iovt));

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, FALSE,
                buf_size + buf2_size + buf3_size, &res);

        test_sum(buf_ptr, buf_size, buf_sum, FALSE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, FALSE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, FALSE, &res);

        got_result(&res, "normal vector request");

        /* Clean up. */
        free_buf_and_grant(buf3_ptr, buf3_grant, buf3_size);
        free_buf_and_grant(buf2_ptr, buf2_grant, buf2_size);
        free_buf_and_grant(buf_ptr, buf_grant, buf_size);
}

#define SECTOR_UNALIGN  2       /* word-aligned and sector-unaligned */

static void bad_write(void)
{
        /* Test various illegal write transfer requests, if writing is allowed.
         * If handled correctly, these requests will not actually write data.
         * However, the last test currently erroneously does end up writing.
         */
        u8_t *buf_ptr, *buf2_ptr, *buf3_ptr;
        size_t buf_size, buf2_size, buf3_size;
        cp_grant_id_t buf_grant, buf2_grant, buf3_grant;
        cp_grant_id_t grant;
        u32_t buf_sum, buf2_sum, buf3_sum;
        iovec_s_t iov[3], iovt[3];
        result_t res;

        test_group("bad write requests", may_write);

        if (!may_write)
                return;

        buf_size = buf2_size = buf3_size = BUF_SIZE;

        alloc_buf_and_grant(&buf_ptr, &buf_grant, buf_size, CPF_READ);
        alloc_buf_and_grant(&buf2_ptr, &buf2_grant, buf2_size, CPF_READ);
        alloc_buf_and_grant(&buf3_ptr, &buf3_grant, buf3_size, CPF_READ);

        iovt[0].iov_grant = buf_grant;
        iovt[0].iov_size = buf_size;
        iovt[1].iov_grant = buf2_grant;
        iovt[1].iov_size = buf2_size;
        iovt[2].iov_grant = buf3_grant;
        iovt[2].iov_size = buf3_size;

        /* Test sector-unaligned write position. */
        memcpy(iov, iovt, sizeof(iovt));

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(SECTOR_UNALIGN), iov, 3, TRUE, EINVAL,
                &res);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "sector-unaligned write position");

        /* Test sector-unaligned write size. */
        memcpy(iov, iovt, sizeof(iovt));
        iov[1].iov_size -= SECTOR_UNALIGN;

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, TRUE, EINVAL, &res);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "sector-unaligned write size");

        /* Test write-only grant in iovec element. */
        memcpy(iov, iovt, sizeof(iovt));
        if ((grant = cpf_grant_direct(driver_endpt, (vir_bytes) buf2_ptr,
                        buf2_size, CPF_WRITE)) == GRANT_INVALID)
                panic("unable to allocate grant");

        iov[1].iov_grant = grant;

        buf_sum = fill_rand(buf_ptr, buf_size);
        buf2_sum = fill_rand(buf2_ptr, buf2_size);
        buf3_sum = fill_rand(buf3_ptr, buf3_size);

        raw_xfer(driver_minor, cvu64(0), iov, 3, TRUE, EINVAL, &res);

        accept_result(&res, RESULT_BADSTATUS, EPERM);

        test_sum(buf_ptr, buf_size, buf_sum, TRUE, &res);
        test_sum(buf2_ptr, buf2_size, buf2_sum, TRUE, &res);
        test_sum(buf3_ptr, buf3_size, buf3_sum, TRUE, &res);

        got_result(&res, "write-only grant in iovec element");

        cpf_revoke(grant);

        /* Clean up. */
        free_buf_and_grant(buf3_ptr, buf3_grant, buf3_size);
        free_buf_and_grant(buf2_ptr, buf2_grant, buf2_size);
        free_buf_and_grant(buf_ptr, buf_grant, buf_size);
}

static void vector_and_large_sub(size_t small_size)
{
        /* Check whether large vectored requests, and large single requests,
         * succeed.
         */
        size_t large_size, buf_size, buf2_size;
        u8_t *buf_ptr, *buf2_ptr;
        iovec_t iovec[NR_IOREQS];
        u64_t base_pos;
        result_t res;
        int i;

        base_pos = cvu64(sector_size);

        large_size = small_size * NR_IOREQS;

        buf_size = large_size + sizeof(u32_t) * 2;
        buf2_size = large_size + sizeof(u32_t) * (NR_IOREQS + 1);

        buf_ptr = alloc_contig(buf_size, 0, NULL);
        buf2_ptr = alloc_contig(buf2_size, 0, NULL);
        if (buf_ptr == NULL || buf2_ptr == NULL)
                panic("unable to allocate memory");

        /* The first buffer has one large chunk with dword-sized guards on each
         * side. LPTR(n) points to the start of the nth small data chunk within
         * the large chunk. The second buffer contains several small chunks. It
         * has dword-sized guards before each chunk and after the last chunk.
         * SPTR(n) points to the start of the nth small chunk.
         */
#define SPTR(n) (buf2_ptr + sizeof(u32_t) + (n) * (sizeof(u32_t) + small_size))
#define LPTR(n) (buf_ptr + sizeof(u32_t) + small_size * (n))

        /* Write one large chunk, if writing is allowed. */
        if (may_write) {
                fill_rand(buf_ptr, buf_size); /* don't need the checksum */

                iovec[0].iov_addr = (vir_bytes) (buf_ptr + sizeof(u32_t));
                iovec[0].iov_size = large_size;

                vir_xfer(driver_minor, base_pos, iovec, 1, TRUE, large_size,
                        &res);

                got_result(&res, "large write");
        }

        /* Read back in many small chunks. If writing is not allowed, do not
         * check checksums.
         */
        for (i = 0; i < NR_IOREQS; i++) {
                * (((u32_t *) SPTR(i)) - 1) = 0xDEADBEEFL + i;
                iovec[i].iov_addr = (vir_bytes) SPTR(i);
                iovec[i].iov_size = small_size;
        }
        * (((u32_t *) SPTR(i)) - 1) = 0xFEEDFACEL;

        vir_xfer(driver_minor, base_pos, iovec, NR_IOREQS, FALSE, large_size,
                &res);

        if (res.type == RESULT_OK) {
                for (i = 0; i < NR_IOREQS; i++) {
                        if (* (((u32_t *) SPTR(i)) - 1) != 0xDEADBEEFL + i)
                                set_result(&res, RESULT_OVERFLOW, 0);
                }
                if (* (((u32_t *) SPTR(i)) - 1) != 0xFEEDFACEL)
                        set_result(&res, RESULT_OVERFLOW, 0);
        }

        if (res.type == RESULT_OK && may_write) {
                for (i = 0; i < NR_IOREQS; i++) {
                        test_sum(SPTR(i), small_size,
                                get_sum(LPTR(i), small_size), TRUE, &res);
                }
        }

        got_result(&res, "vectored read");

        /* Write new data in many small chunks, if writing is allowed. */
        if (may_write) {
                fill_rand(buf2_ptr, buf2_size); /* don't need the checksum */

                for (i = 0; i < NR_IOREQS; i++) {
                        iovec[i].iov_addr = (vir_bytes) SPTR(i);
                        iovec[i].iov_size = small_size;
                }

                vir_xfer(driver_minor, base_pos, iovec, NR_IOREQS, TRUE,
                        large_size, &res);

                got_result(&res, "vectored write");
        }

        /* Read back in one large chunk. If writing is allowed, the checksums
         * must match the last write; otherwise, they must match the last read.
         * In both cases, the expected content is in the second buffer.
         */

        * (u32_t *) buf_ptr = 0xCAFEBABEL;
        * (u32_t *) (buf_ptr + sizeof(u32_t) + large_size) = 0xDECAFBADL;

        iovec[0].iov_addr = (vir_bytes) (buf_ptr + sizeof(u32_t));
        iovec[0].iov_size = large_size;

        vir_xfer(driver_minor, base_pos, iovec, 1, FALSE, large_size, &res);

        if (res.type == RESULT_OK) {
                if (* (u32_t *) buf_ptr != 0xCAFEBABEL)
                        set_result(&res, RESULT_OVERFLOW, 0);
                if (* (u32_t *) (buf_ptr + sizeof(u32_t) + large_size) !=
                                0xDECAFBADL)
                        set_result(&res, RESULT_OVERFLOW, 0);
        }

        if (res.type == RESULT_OK) {
                for (i = 0; i < NR_IOREQS; i++) {
                        test_sum(SPTR(i), small_size,
                                get_sum(LPTR(i), small_size), TRUE, &res);
                }
        }

        got_result(&res, "large read");

#undef LPTR
#undef SPTR

        /* Clean up. */
        free_contig(buf2_ptr, buf2_size);
        free_contig(buf_ptr, buf_size);
}

static void vector_and_large(void)
{
        /* Check whether large vectored requests, and large single requests,
         * succeed. These are request patterns commonly used by MFS and the
         * filter driver, respectively. We try the same test twice: once with
         * a common block size, and once to push against the max request size.
         */
        size_t max_block;

        /* Compute the largest sector multiple which, when multiplied by
         * NR_IOREQS, is no more than the maximum transfer size. Note that if
         * max_size is not a multiple of sector_size, we're not going up to the
         * limit entirely this way.
         */
        max_block = max_size / NR_IOREQS;
        max_block -= max_block % sector_size;

#define COMMON_BLOCK_SIZE       4096

        test_group("vector and large, common block", TRUE);

        vector_and_large_sub(COMMON_BLOCK_SIZE);

        if (max_block != COMMON_BLOCK_SIZE) {
                test_group("vector and large, large block", TRUE);

                vector_and_large_sub(max_block);
        }
}

static void open_device(dev_t minor)
{
        /* Open a partition or subpartition. Remember that it has been opened,
         * so that we can reopen it later in the event of a driver crash.
         */
        message m;
        result_t res;

        memset(&m, 0, sizeof(m));
        m.m_type = BDEV_OPEN;
        m.BDEV_MINOR = minor;
        m.BDEV_ACCESS = may_write ? (R_BIT | W_BIT) : R_BIT;
        m.BDEV_ID = lrand48();

        sendrec_driver(&m, OK, &res);

        /* We assume that this call is supposed to succeed. We pretend it
         * always succeeds, so that close_device() won't get confused later.
         */
        assert(nr_opened < NR_OPENED);
        opened[nr_opened++] = minor;

        got_result(&res, minor == driver_minor ? "opening the main partition" :
                "opening a subpartition");
}

static void close_device(dev_t minor)
{
        /* Close a partition or subpartition. Remove it from the list of opened
         * devices.
         */
        message m;
        result_t res;
        int i;

        memset(&m, 0, sizeof(m));
        m.m_type = BDEV_CLOSE;
        m.BDEV_MINOR = minor;
        m.BDEV_ID = lrand48();

        sendrec_driver(&m, OK, &res);

        assert(nr_opened > 0);
        for (i = 0; i < nr_opened; i++) {
                if (opened[i] == minor) {
                        opened[i] = opened[--nr_opened];
                        break;
                }
        }

        got_result(&res, minor == driver_minor ? "closing the main partition" :
                "closing a subpartition");
}

static int vir_ioctl(dev_t minor, int req, void *ptr, ssize_t exp,
        result_t *res)
{
        /* Perform an I/O control request, using a local buffer.
         */
        cp_grant_id_t grant;
        message m;
        int r, perm;

        assert(!_MINIX_IOCTL_BIG(req)); /* not supported */

        perm = 0;
        if (_MINIX_IOCTL_IOR(req)) perm |= CPF_WRITE;
        if (_MINIX_IOCTL_IOW(req)) perm |= CPF_READ;

        if ((grant = cpf_grant_direct(driver_endpt, (vir_bytes) ptr,
                        _MINIX_IOCTL_SIZE(req), perm)) == GRANT_INVALID)
                panic("unable to allocate grant");

        memset(&m, 0, sizeof(m));
        m.m_type = BDEV_IOCTL;
        m.BDEV_MINOR = minor;
        m.BDEV_POS_LO = 0L;
        m.BDEV_POS_HI = 0L;
        m.BDEV_REQUEST = req;
        m.BDEV_GRANT = grant;
        m.BDEV_ID = lrand48();

        r = sendrec_driver(&m, exp, res);

        if (cpf_revoke(grant) != OK)
                panic("unable to revoke grant");

        return r;
}

static void misc_ioctl(void)
{
        /* Test some ioctls.
         */
        result_t res;
        int openct;

        test_group("test miscellaneous ioctls", TRUE);

        /* Retrieve the main partition's base and size. Save for later. */
        vir_ioctl(driver_minor, DIOCGETP, &part, OK, &res);

        got_result(&res, "ioctl to get partition");

        /* The other tests do not check whether there is sufficient room. */
        if (res.type == RESULT_OK && cmp64u(part.size, max_size * 2) < 0)
                printf("WARNING: small partition, some tests may fail\n");

        /* Test retrieving global driver open count. */
        openct = 0x0badcafe;

        vir_ioctl(driver_minor, DIOCOPENCT, &openct, OK, &res);

        /* We assume that we're the only client to the driver right now. */
        if (res.type == RESULT_OK && openct != 1) {
                res.type = RESULT_BADVALUE;
                res.value = openct;
        }

        got_result(&res, "ioctl to get open count");

        /* Test increasing and re-retrieving open count. */
        open_device(driver_minor);

        openct = 0x0badcafe;

        vir_ioctl(driver_minor, DIOCOPENCT, &openct, OK, &res);

        if (res.type == RESULT_OK && openct != 2) {
                res.type = RESULT_BADVALUE;
                res.value = openct;
        }

        got_result(&res, "increased open count after opening");

        /* Test decreasing and re-retrieving open count. */
        close_device(driver_minor);

        openct = 0x0badcafe;

        vir_ioctl(driver_minor, DIOCOPENCT, &openct, OK, &res);

        if (res.type == RESULT_OK && openct != 1) {
                res.type = RESULT_BADVALUE;
                res.value = openct;
        }

        got_result(&res, "decreased open count after closing");
}

static void read_limits(dev_t sub0_minor, dev_t sub1_minor, size_t sub_size)
{
        /* Test reads up to, across, and beyond partition limits.
         */
        u8_t *buf_ptr;
        size_t buf_size;
        u32_t sum, sum2, sum3;
        result_t res;

        test_group("read around subpartition limits", TRUE);

        buf_size = sector_size * 3;

        if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        /* Read one sector up to the partition limit. */
        fill_rand(buf_ptr, buf_size);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size), buf_ptr,
                sector_size, FALSE, sector_size, &res);

        sum = get_sum(buf_ptr, sector_size);

        got_result(&res, "one sector read up to partition end");

        /* Read three sectors up to the partition limit. */
        fill_rand(buf_ptr, buf_size);

        simple_xfer(sub0_minor, cvu64(sub_size - buf_size), buf_ptr, buf_size,
                FALSE, buf_size, &res);

        test_sum(buf_ptr + sector_size * 2, sector_size, sum, TRUE, &res);

        sum2 = get_sum(buf_ptr + sector_size, sector_size * 2);

        got_result(&res, "multisector read up to partition end");

        /* Read three sectors, two up to and one beyond the partition end. */
        fill_rand(buf_ptr, buf_size);
        sum3 = get_sum(buf_ptr + sector_size * 2, sector_size);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size * 2), buf_ptr,
                buf_size, FALSE, sector_size * 2, &res);

        test_sum(buf_ptr, sector_size * 2, sum2, TRUE, &res);
        test_sum(buf_ptr + sector_size * 2, sector_size, sum3, TRUE, &res);

        got_result(&res, "read somewhat across partition end");

        /* Read three sectors, one up to and two beyond the partition end. */
        fill_rand(buf_ptr, buf_size);
        sum2 = get_sum(buf_ptr + sector_size, sector_size * 2);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size), buf_ptr,
                buf_size, FALSE, sector_size, &res);

        test_sum(buf_ptr, sector_size, sum, TRUE, &res);
        test_sum(buf_ptr + sector_size, sector_size * 2, sum2, TRUE, &res);

        got_result(&res, "read mostly across partition end");

        /* Read one sector starting at the partition end. */
        sum = fill_rand(buf_ptr, buf_size);
        sum2 = get_sum(buf_ptr, sector_size);

        simple_xfer(sub0_minor, cvu64(sub_size), buf_ptr, sector_size, FALSE,
                0, &res);

        test_sum(buf_ptr, sector_size, sum2, TRUE, &res);

        got_result(&res, "one sector read at partition end");

        /* Read three sectors starting at the partition end. */
        simple_xfer(sub0_minor, cvu64(sub_size), buf_ptr, buf_size, FALSE, 0,
                &res);

        test_sum(buf_ptr, buf_size, sum, TRUE, &res);

        got_result(&res, "multisector read at partition end");

        /* Read one sector beyond the partition end. */
        simple_xfer(sub0_minor, cvu64(sub_size + sector_size), buf_ptr,
                buf_size, FALSE, 0, &res);

        test_sum(buf_ptr, sector_size, sum2, TRUE, &res);

        got_result(&res, "single sector read beyond partition end");

        /* Read three sectors way beyond the partition end. */
        simple_xfer(sub0_minor, make64(0L, 0x10000000L), buf_ptr,
                buf_size, FALSE, 0, &res);

        test_sum(buf_ptr, buf_size, sum, TRUE, &res);

        /* Test negative offsets. This request should return EOF or fail; we
         * assume that it return EOF here (because that is what the AHCI driver
         * does, to avoid producing errors for requests close to the 2^64 byte
         * position limit [yes, this will indeed never happen anyway]). This is
         * more or less a bad requests test, but we cannot do it without
         * setting up subpartitions first.
         */
        simple_xfer(sub1_minor, make64(0xffffffffL - sector_size + 1,
                0xffffffffL), buf_ptr, sector_size, FALSE, 0, &res);

        test_sum(buf_ptr, sector_size, sum2, TRUE, &res);

        got_result(&res, "read with negative offset");

        /* Clean up. */
        free_contig(buf_ptr, buf_size);
}

static void write_limits(dev_t sub0_minor, dev_t sub1_minor, size_t sub_size)
{
        /* Test writes up to, across, and beyond partition limits. Use the
         * first given subpartition to test, and the second to make sure there
         * are no overruns. The given size is the size of each of the
         * subpartitions. Note that the necessity to check the results using
         * readback, makes this more or less a superset of the read test.
         */
        u8_t *buf_ptr;
        size_t buf_size;
        u32_t sum, sum2, sum3, sub1_sum;
        result_t res;

        test_group("write around subpartition limits", may_write);

        if (!may_write)
                return;

        buf_size = sector_size * 3;

        if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        /* Write to the start of the second subpartition, so that we can
         * reliably check whether the contents have changed later.
         */
        sub1_sum = fill_rand(buf_ptr, buf_size);

        simple_xfer(sub1_minor, cvu64(0), buf_ptr, buf_size, TRUE, buf_size,
                &res);

        got_result(&res, "write to second subpartition");

        /* Write one sector, up to the partition limit. */
        sum = fill_rand(buf_ptr, sector_size);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size), buf_ptr,
                sector_size, TRUE, sector_size, &res);

        got_result(&res, "write up to partition end");

        /* Read back to make sure the results have persisted. */
        fill_rand(buf_ptr, sector_size * 2);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size * 2), buf_ptr,
                sector_size * 2, FALSE, sector_size * 2, &res);

        test_sum(buf_ptr + sector_size, sector_size, sum, TRUE, &res);

        got_result(&res, "read up to partition end");

        /* Write three sectors, two up to and one beyond the partition end. */
        fill_rand(buf_ptr, buf_size);
        sum = get_sum(buf_ptr + sector_size, sector_size);
        sum3 = get_sum(buf_ptr, sector_size);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size * 2), buf_ptr,
                buf_size, TRUE, sector_size * 2, &res);

        got_result(&res, "write somewhat across partition end");

        /* Read three sectors, one up to and two beyond the partition end. */
        fill_rand(buf_ptr, buf_size);
        sum2 = get_sum(buf_ptr + sector_size, sector_size * 2);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size), buf_ptr,
                buf_size, FALSE, sector_size, &res);

        test_sum(buf_ptr, sector_size, sum, TRUE, &res);
        test_sum(buf_ptr + sector_size, sector_size * 2, sum2, TRUE, &res);

        got_result(&res, "read mostly across partition end");

        /* Repeat this but with write and read start positions swapped. */
        fill_rand(buf_ptr, buf_size);
        sum = get_sum(buf_ptr, sector_size);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size), buf_ptr,
                buf_size, TRUE, sector_size, &res);

        got_result(&res, "write mostly across partition end");

        fill_rand(buf_ptr, buf_size);
        sum2 = get_sum(buf_ptr + sector_size * 2, sector_size);

        simple_xfer(sub0_minor, cvu64(sub_size - sector_size * 2), buf_ptr,
                buf_size, FALSE, sector_size * 2, &res);

        test_sum(buf_ptr, sector_size, sum3, TRUE, &res);
        test_sum(buf_ptr + sector_size, sector_size, sum, TRUE, &res);
        test_sum(buf_ptr + sector_size * 2, sector_size, sum2, TRUE, &res);

        got_result(&res, "read somewhat across partition end");

        /* Write one sector at the end of the partition. */
        fill_rand(buf_ptr, sector_size);

        simple_xfer(sub0_minor, cvu64(sub_size), buf_ptr, sector_size, TRUE, 0,
                &res);

        got_result(&res, "write at partition end");

        /* Write one sector beyond the end of the partition. */
        simple_xfer(sub0_minor, cvu64(sub_size + sector_size), buf_ptr,
                sector_size, TRUE, 0, &res);

        got_result(&res, "write beyond partition end");

        /* Read from the start of the second subpartition, and see if it
         * matches what we wrote into it earlier.
         */
        fill_rand(buf_ptr, buf_size);

        simple_xfer(sub1_minor, cvu64(0), buf_ptr, buf_size, FALSE, buf_size,
                &res);

        test_sum(buf_ptr, buf_size, sub1_sum, TRUE, &res);

        got_result(&res, "read from second subpartition");

        /* Test offset wrapping, but this time for writes. */
        fill_rand(buf_ptr, sector_size);

        simple_xfer(sub1_minor, make64(0xffffffffL - sector_size + 1,
                0xffffffffL), buf_ptr, sector_size, TRUE, 0, &res);

        got_result(&res, "write with negative offset");

        /* If the last request erroneously succeeded, it would have overwritten
         * the last sector of the first subpartition.
         */
        simple_xfer(sub0_minor, cvu64(sub_size - sector_size), buf_ptr,
                sector_size, FALSE, sector_size, &res);

        test_sum(buf_ptr, sector_size, sum, TRUE, &res);

        got_result(&res, "read up to partition end");

        /* Clean up. */
        free_contig(buf_ptr, buf_size);
}

static void vir_limits(dev_t sub0_minor, dev_t sub1_minor, int part_secs)
{
        /* Create virtual, temporary subpartitions through the DIOCSETP ioctl,
         * and perform tests on the resulting subpartitions.
         */
        struct partition subpart, subpart2;
        size_t sub_size;
        result_t res;

        test_group("virtual subpartition limits", TRUE);

        /* Open the subpartitions. This is somewhat dodgy; we rely on the
         * driver allowing this even if no subpartitions exist. We cannot do
         * this test without doing a DIOCSETP on an open subdevice, though.
         */
        open_device(sub0_minor);
        open_device(sub1_minor);

        sub_size = sector_size * part_secs;

        /* Set, and check, the size of the first subpartition. */
        subpart = part;
        subpart.size = cvu64(sub_size);

        vir_ioctl(sub0_minor, DIOCSETP, &subpart, OK, &res);

        got_result(&res, "ioctl to set first subpartition");

        vir_ioctl(sub0_minor, DIOCGETP, &subpart2, OK, &res);

        if (res.type == RESULT_OK && (cmp64(subpart.base, subpart2.base) ||
                        cmp64(subpart.size, subpart2.size))) {
                res.type = RESULT_BADVALUE;
                res.value = 0;
        }

        got_result(&res, "ioctl to get first subpartition");

        /* Set, and check, the base and size of the second subpartition. */
        subpart = part;
        subpart.base = add64u(subpart.base, sub_size);
        subpart.size = cvu64(sub_size);

        vir_ioctl(sub1_minor, DIOCSETP, &subpart, OK, &res);

        got_result(&res, "ioctl to set second subpartition");

        vir_ioctl(sub1_minor, DIOCGETP, &subpart2, OK, &res);

        if (res.type == RESULT_OK && (cmp64(subpart.base, subpart2.base) ||
                        cmp64(subpart.size, subpart2.size))) {
                res.type = RESULT_BADVALUE;
                res.value = 0;
        }

        got_result(&res, "ioctl to get second subpartition");

        /* Perform the actual I/O tests. */
        read_limits(sub0_minor, sub1_minor, sub_size);

        write_limits(sub0_minor, sub1_minor, sub_size);

        /* Clean up. */
        close_device(sub1_minor);
        close_device(sub0_minor);
}

static void real_limits(dev_t sub0_minor, dev_t sub1_minor, int part_secs)
{
        /* Create our own subpartitions by writing a partition table, and
         * perform tests on the resulting real subpartitions.
         */
        u8_t *buf_ptr;
        size_t buf_size, sub_size;
        struct partition subpart;
        struct part_entry *entry;
        result_t res;

        test_group("real subpartition limits", may_write);

        if (!may_write)
                return;

        sub_size = sector_size * part_secs;

        /* Technically, we should be using 512 instead of sector_size in
         * various places, because even on CD-ROMs, the partition tables are
         * 512 bytes and the sector counts are based on 512-byte sectors in it.
         * We ignore this subtlety because CD-ROMs are assumed to be read-only
         * anyway.
         */
        buf_size = sector_size;

        if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        memset(buf_ptr, 0, buf_size);

        /* Write an invalid partition table. */
        simple_xfer(driver_minor, cvu64(0), buf_ptr, buf_size, TRUE, buf_size,
                &res);

        got_result(&res, "write of invalid partition table");

        /* Get the disk driver to reread the partition table. This should
         * happen (at least) when the device is fully closed and then reopened.
         * The ioctl test already made sure that we're the only client.
         */
        close_device(driver_minor);
        open_device(driver_minor);

        /* See if our changes are visible. We expect the subpartitions to have
         * a size of zero now, indicating that they're not there. For actual
         * subpartitions (as opposed to normal partitions), this requires the
         * driver to zero them out, because the partition code does not do so.
         */
        open_device(sub0_minor);
        open_device(sub1_minor);

        vir_ioctl(sub0_minor, DIOCGETP, &subpart, 0, &res);

        if (res.type == RESULT_OK && cmp64u(subpart.size, 0)) {
                res.type = RESULT_BADVALUE;
                res.value = ex64lo(subpart.size);
        }

        got_result(&res, "ioctl to get first subpartition");

        vir_ioctl(sub1_minor, DIOCGETP, &subpart, 0, &res);

        if (res.type == RESULT_OK && cmp64u(subpart.size, 0)) {
                res.type = RESULT_BADVALUE;
                res.value = ex64lo(subpart.size);
        }

        got_result(&res, "ioctl to get second subpartition");

        close_device(sub1_minor);
        close_device(sub0_minor);

        /* Now write a valid partition table. */
        memset(buf_ptr, 0, buf_size);

        entry = (struct part_entry *) &buf_ptr[PART_TABLE_OFF];

        entry[0].sysind = MINIX_PART;
        entry[0].lowsec = div64u(part.base, sector_size) + 1;
        entry[0].size = part_secs;
        entry[1].sysind = MINIX_PART;
        entry[1].lowsec = entry[0].lowsec + entry[0].size;
        entry[1].size = part_secs;

        buf_ptr[510] = 0x55;
        buf_ptr[511] = 0xAA;

        simple_xfer(driver_minor, cvu64(0), buf_ptr, buf_size, TRUE, buf_size,
                &res);

        got_result(&res, "write of valid partition table");

        /* Same as above. */
        close_device(driver_minor);
        open_device(driver_minor);

        /* Again, see if our changes are visible. This time the proper base and
         * size should be there.
         */
        open_device(sub0_minor);
        open_device(sub1_minor);

        vir_ioctl(sub0_minor, DIOCGETP, &subpart, 0, &res);

        if (res.type == RESULT_OK && (cmp64(subpart.base,
                add64u(part.base, sector_size)) ||
                cmp64u(subpart.size, part_secs * sector_size))) {

                res.type = RESULT_BADVALUE;
                res.value = 0;
        }

        got_result(&res, "ioctl to get first subpartition");

        vir_ioctl(sub1_minor, DIOCGETP, &subpart, 0, &res);

        if (res.type == RESULT_OK && (cmp64(subpart.base,
                add64u(part.base, (1 + part_secs) * sector_size)) ||
                cmp64u(subpart.size, part_secs * sector_size))) {

                res.type = RESULT_BADVALUE;
                res.value = 0;
        }

        got_result(&res, "ioctl to get second subpartition");

        /* Now perform the actual I/O tests. */
        read_limits(sub0_minor, sub1_minor, sub_size);

        write_limits(sub0_minor, sub1_minor, sub_size);

        /* Clean up. */
        close_device(sub0_minor);
        close_device(sub1_minor);

        free_contig(buf_ptr, buf_size);
}

static void part_limits(void)
{
        /* Test reads and writes up to, across, and beyond partition limits.
         * As a side effect, test reading and writing partition sizes and
         * rereading partition tables.
         */
        dev_t par, sub0_minor, sub1_minor;

        /* First determine the first two subpartitions of the partition that we
         * are operating on. If we are already operating on a subpartition, we
         * cannot conduct this test.
         */
        if (driver_minor >= MINOR_d0p0s0) {
                printf("WARNING: operating on subpartition, "
                        "skipping partition tests\n");
                return;
        }
        par = driver_minor % DEV_PER_DRIVE;
        if (par > 0) /* adapted from libdriver's drvlib code */
                sub0_minor = MINOR_d0p0s0 + ((driver_minor / DEV_PER_DRIVE) *
                        NR_PARTITIONS + par - 1) * NR_PARTITIONS;
        else
                sub0_minor = driver_minor + 1;
        sub1_minor = sub0_minor + 1;

#define PART_SECS       9       /* sectors in each partition. must be >= 4. */

        /* First try the test with temporarily specified subpartitions. */
        vir_limits(sub0_minor, sub1_minor, PART_SECS);

        /* Then, if we're allowed to write, try the test with real, persisted
         * subpartitions.
         */
        real_limits(sub0_minor, sub1_minor, PART_SECS - 1);

}

static void unaligned_size_io(u64_t base_pos, u8_t *buf_ptr, size_t buf_size,
        u8_t *sec_ptr[2], int sectors, int pattern, u32_t ssum[5])
{
        /* Perform a single small-element I/O read, write, readback test.
         * The number of sectors and the pattern varies with each call.
         * The ssum array has to be updated to reflect the five sectors'
         * checksums on disk, if writing is enabled. Note that for
         */
        iovec_t iov[3], iovt[3];
        u32_t rsum[3];
        result_t res;
        size_t total_size;
        int i, nr_req;

        base_pos = add64u(base_pos, sector_size);
        total_size = sector_size * sectors;

        /* If the limit is two elements per sector, we cannot test three
         * elements in a single sector.
         */
        if (sector_size / element_size == 2 && sectors == 1 && pattern == 2)
                return;

        /* Set up the buffers and I/O vector. We use different buffers for the
         * elements to minimize the chance that something "accidentally" goes
         * right, but that means we have to do memory copying to do checksum
         * computation.
         */
        fill_rand(sec_ptr[0], sector_size);
        rsum[0] =
                get_sum(sec_ptr[0] + element_size, sector_size - element_size);

        fill_rand(buf_ptr, buf_size);

        switch (pattern) {
        case 0:
                /* First pattern: a small element on the left. */
                iovt[0].iov_addr = (vir_bytes) sec_ptr[0];
                iovt[0].iov_size = element_size;

                iovt[1].iov_addr = (vir_bytes) buf_ptr;
                iovt[1].iov_size = total_size - element_size;
                rsum[1] = get_sum(buf_ptr + iovt[1].iov_size, element_size);

                nr_req = 2;
                break;
        case 1:
                /* Second pattern: a small element on the right. */
                iovt[0].iov_addr = (vir_bytes) buf_ptr;
                iovt[0].iov_size = total_size - element_size;
                rsum[1] = get_sum(buf_ptr + iovt[0].iov_size, element_size);

                iovt[1].iov_addr = (vir_bytes) sec_ptr[0];
                iovt[1].iov_size = element_size;

                nr_req = 2;
                break;
        case 2:
                /* Third pattern: a small element on each side. */
                iovt[0].iov_addr = (vir_bytes) sec_ptr[0];
                iovt[0].iov_size = element_size;

                iovt[1].iov_addr = (vir_bytes) buf_ptr;
                iovt[1].iov_size = total_size - element_size * 2;
                rsum[1] = get_sum(buf_ptr + iovt[1].iov_size,
                        element_size * 2);

                fill_rand(sec_ptr[1], sector_size);
                iovt[2].iov_addr = (vir_bytes) sec_ptr[1];
                iovt[2].iov_size = element_size;
                rsum[2] = get_sum(sec_ptr[1] + element_size,
                        sector_size - element_size);

                nr_req = 3;
                break;
        default:
                assert(0);
        }

        /* Perform a read with small elements, and test whether the result is
         * as expected.
         */
        memcpy(iov, iovt, sizeof(iov));
        vir_xfer(driver_minor, base_pos, iov, nr_req, FALSE, total_size, &res);

        test_sum(sec_ptr[0] + element_size, sector_size - element_size,
                rsum[0], TRUE, &res);

        switch (pattern) {
        case 0:
                test_sum(buf_ptr + iovt[1].iov_size, element_size, rsum[1],
                        TRUE, &res);
                memmove(buf_ptr + element_size, buf_ptr, iovt[1].iov_size);
                memcpy(buf_ptr, sec_ptr[0], element_size);
                break;
        case 1:
                test_sum(buf_ptr + iovt[0].iov_size, element_size, rsum[1],
                        TRUE, &res);
                memcpy(buf_ptr + iovt[0].iov_size, sec_ptr[0], element_size);
                break;
        case 2:
                test_sum(buf_ptr + iovt[1].iov_size, element_size * 2, rsum[1],
                        TRUE, &res);
                test_sum(sec_ptr[1] + element_size, sector_size - element_size,
                        rsum[2], TRUE, &res);
                memmove(buf_ptr + element_size, buf_ptr, iovt[1].iov_size);
                memcpy(buf_ptr, sec_ptr[0], element_size);
                memcpy(buf_ptr + element_size + iovt[1].iov_size, sec_ptr[1],
                        element_size);

                break;
        }

        for (i = 0; i < sectors; i++)
                test_sum(buf_ptr + sector_size * i, sector_size, ssum[1 + i],
                        TRUE, &res);

        got_result(&res, "read with small elements");

        /* In read-only mode, we have nothing more to do. */
        if (!may_write)
                return;

        /* Use the same I/O vector to perform a write with small elements.
         * This will cause the checksums of the target sectors to change,
         * so we need to update those for both verification and later usage.
         */
        for (i = 0; i < sectors; i++)
                ssum[1 + i] =
                        fill_rand(buf_ptr + sector_size * i, sector_size);

        switch (pattern) {
        case 0:
                memcpy(sec_ptr[0], buf_ptr, element_size);
                memmove(buf_ptr, buf_ptr + element_size, iovt[1].iov_size);
                fill_rand(buf_ptr + iovt[1].iov_size, element_size);
                break;
        case 1:
                memcpy(sec_ptr[0], buf_ptr + iovt[0].iov_size, element_size);
                fill_rand(buf_ptr + iovt[0].iov_size, element_size);
                break;
        case 2:
                memcpy(sec_ptr[0], buf_ptr, element_size);
                memcpy(sec_ptr[1], buf_ptr + element_size + iovt[1].iov_size,
                        element_size);
                memmove(buf_ptr, buf_ptr + element_size, iovt[1].iov_size);
                fill_rand(buf_ptr + iovt[1].iov_size, element_size * 2);
                break;
        }

        memcpy(iov, iovt, sizeof(iov));

        vir_xfer(driver_minor, base_pos, iov, nr_req, TRUE, total_size, &res);

        got_result(&res, "write with small elements");

        /* Now perform normal readback verification. */
        fill_rand(buf_ptr, sector_size * 3);

        simple_xfer(driver_minor, base_pos, buf_ptr, sector_size * 3, FALSE,
                sector_size * 3, &res);

        for (i = 0; i < 3; i++)
                test_sum(buf_ptr + sector_size * i, sector_size, ssum[1 + i],
                        TRUE, &res);

        got_result(&res, "readback verification");
}

static void unaligned_size(void)
{
        /* Test sector-unaligned sizes in I/O vector elements. The total size
         * of the request, however, has to add up to the sector size.
         */
        u8_t *buf_ptr, *sec_ptr[2];
        size_t buf_size;
        u32_t sum = 0L, ssum[5];
        u64_t base_pos;
        result_t res;
        int i;

        test_group("sector-unaligned elements", sector_size != element_size);

        /* We can only do this test if the driver allows small elements. */
        if (sector_size == element_size)
                return;

        /* Crashing on bad user input, terrible! */
        assert(sector_size % element_size == 0);

        /* Establish a baseline by writing and reading back five sectors; or
         * by reading only, if writing is disabled.
         */
        buf_size = sector_size * 5;

        base_pos = cvu64(sector_size * 2);

        if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        if ((sec_ptr[0] = alloc_contig(sector_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        if ((sec_ptr[1] = alloc_contig(sector_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        if (may_write) {
                sum = fill_rand(buf_ptr, buf_size);

                for (i = 0; i < 5; i++)
                        ssum[i] = get_sum(buf_ptr + sector_size * i,
                                sector_size);

                simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, TRUE,
                        buf_size, &res);

                got_result(&res, "write several sectors");
        }

        fill_rand(buf_ptr, buf_size);

        simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, FALSE, buf_size,
                &res);

        if (may_write) {
                test_sum(buf_ptr, buf_size, sum, TRUE, &res);
        }
        else {
                for (i = 0; i < 5; i++)
                        ssum[i] = get_sum(buf_ptr + sector_size * i,
                                sector_size);
        }

        got_result(&res, "read several sectors");

        /* We do nine subtests. The first three involve only the second sector;
         * the second three involve the second and third sectors, and the third
         * three involve all of the middle sectors. Each triplet tests small
         * elements at the left, at the right, and at both the left and the
         * right of the area. For each operation, we first do an unaligned
         * read, and if writing is enabled, an unaligned write and an aligned
         * read.
         */
        for (i = 0; i < 9; i++) {
                unaligned_size_io(base_pos, buf_ptr, buf_size, sec_ptr,
                        i / 3 + 1, i % 3, ssum);
        }

        /* If writing was enabled, make sure that the first and fifth sector
         * have remained untouched.
         */
        if (may_write) {
                fill_rand(buf_ptr, buf_size);

                simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, FALSE,
                        buf_size, &res);

                test_sum(buf_ptr, sector_size, ssum[0], TRUE, &res);
                test_sum(buf_ptr + sector_size * 4, sector_size, ssum[4], TRUE,
                        &res);

                got_result(&res, "check first and last sectors");
        }

        /* Clean up. */
        free_contig(sec_ptr[1], sector_size);
        free_contig(sec_ptr[0], sector_size);
        free_contig(buf_ptr, buf_size);
}

static void unaligned_pos1(void)
{
        /* Test sector-unaligned positions and total sizes for requests. This
         * is a read-only test as no driver currently supports sector-unaligned
         * writes. In this context, the term "lead" means an unwanted first
         * part of a sector, and "trail" means an unwanted last part of a
         * sector.
         */
        u8_t *buf_ptr, *buf2_ptr;
        size_t buf_size, buf2_size, size;
        u32_t sum, sum2;
        u64_t base_pos;
        result_t res;

        test_group("sector-unaligned positions, part one",
                min_read != sector_size);

        /* We can only do this test if the driver allows small read requests.
         */
        if (min_read == sector_size)
                return;

        assert(sector_size % min_read == 0);
        assert(min_read % element_size == 0);

        /* Establish a baseline by writing and reading back three sectors; or
         * by reading only, if writing is disabled.
         */
        buf_size = buf2_size = sector_size * 3;

        base_pos = cvu64(sector_size * 3);

        if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        if ((buf2_ptr = alloc_contig(buf2_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        if (may_write) {
                sum = fill_rand(buf_ptr, buf_size);

                simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, TRUE,
                        buf_size, &res);

                got_result(&res, "write several sectors");
        }

        fill_rand(buf_ptr, buf_size);

        simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, FALSE, buf_size,
                &res);

        if (may_write)
                test_sum(buf_ptr, buf_size, sum, TRUE, &res);

        got_result(&res, "read several sectors");

        /* Start with a simple test that operates within a single sector,
         * first using a lead.
         */
        fill_rand(buf2_ptr, sector_size);
        sum = get_sum(buf2_ptr + min_read, sector_size - min_read);

        simple_xfer(driver_minor, add64u(base_pos, sector_size - min_read),
                buf2_ptr, min_read, FALSE, min_read, &res);

        test_sum(buf2_ptr, min_read, get_sum(buf_ptr + sector_size - min_read,
                min_read), TRUE, &res);
        test_sum(buf2_ptr + min_read, sector_size - min_read, sum, TRUE,
                &res);

        got_result(&res, "single sector read with lead");

        /* Then a trail. */
        fill_rand(buf2_ptr, sector_size);
        sum = get_sum(buf2_ptr, sector_size - min_read);

        simple_xfer(driver_minor, base_pos, buf2_ptr + sector_size - min_read,
                min_read, FALSE, min_read, &res);

        test_sum(buf2_ptr + sector_size - min_read, min_read, get_sum(buf_ptr,
                min_read), TRUE, &res);
        test_sum(buf2_ptr, sector_size - min_read, sum, TRUE, &res);

        got_result(&res, "single sector read with trail");

        /* And then a lead and a trail, unless min_read is half the sector
         * size, in which case this will be another lead test.
         */
        fill_rand(buf2_ptr, sector_size);
        sum = get_sum(buf2_ptr, min_read);
        sum2 = get_sum(buf2_ptr + min_read * 2, sector_size - min_read * 2);

        simple_xfer(driver_minor, add64u(base_pos, min_read),
                buf2_ptr + min_read, min_read, FALSE, min_read, &res);

        test_sum(buf2_ptr + min_read, min_read, get_sum(buf_ptr + min_read,
                min_read), TRUE, &res);
        test_sum(buf2_ptr, min_read, sum, TRUE, &res);
        test_sum(buf2_ptr + min_read * 2, sector_size - min_read * 2, sum2,
                TRUE, &res);

        got_result(&res, "single sector read with lead and trail");

        /* Now do the same but with three sectors, and still only one I/O
         * vector element. First up: lead.
         */
        size = min_read + sector_size * 2;

        fill_rand(buf2_ptr, buf2_size);
        sum = get_sum(buf2_ptr + size, buf2_size - size);

        simple_xfer(driver_minor, add64u(base_pos, sector_size - min_read),
                buf2_ptr, size, FALSE, size, &res);

        test_sum(buf2_ptr, size, get_sum(buf_ptr + sector_size - min_read,
                size), TRUE, &res);
        test_sum(buf2_ptr + size, buf2_size - size, sum, TRUE, &res);

        got_result(&res, "multisector read with lead");

        /* Then trail. */
        fill_rand(buf2_ptr, buf2_size);
        sum = get_sum(buf2_ptr + size, buf2_size - size);

        simple_xfer(driver_minor, base_pos, buf2_ptr, size, FALSE, size, &res);

        test_sum(buf2_ptr, size, get_sum(buf_ptr, size), TRUE, &res);
        test_sum(buf2_ptr + size, buf2_size - size, sum, TRUE, &res);

        got_result(&res, "multisector read with trail");

        /* Then lead and trail. Use sector size as transfer unit to throw off
         * simplistic lead/trail detection.
         */
        fill_rand(buf2_ptr, buf2_size);
        sum = get_sum(buf2_ptr + sector_size, buf2_size - sector_size);

        simple_xfer(driver_minor, add64u(base_pos, min_read), buf2_ptr,
                sector_size, FALSE, sector_size, &res);

        test_sum(buf2_ptr, sector_size, get_sum(buf_ptr + min_read,
                sector_size), TRUE, &res);
        test_sum(buf2_ptr + sector_size, buf2_size - sector_size, sum, TRUE,
                &res);

        got_result(&res, "multisector read with lead and trail");

        /* Clean up. */
        free_contig(buf2_ptr, buf2_size);
        free_contig(buf_ptr, buf_size);
}

static void unaligned_pos2(void)
{
        /* Test sector-unaligned positions and total sizes for requests, second
         * part. This one tests the use of multiple I/O vector elements, and
         * tries to push the limits of the driver by completely filling an I/O
         * vector and going up to the maximum request size.
         */
        u8_t *buf_ptr, *buf2_ptr;
        size_t buf_size, buf2_size, max_block;
        u32_t sum = 0L, sum2 = 0L, rsum[NR_IOREQS];
        u64_t base_pos;
        iovec_t iov[NR_IOREQS];
        result_t res;
        int i;

        test_group("sector-unaligned positions, part two",
                min_read != sector_size);

        /* We can only do this test if the driver allows small read requests.
         */
        if (min_read == sector_size)
                return;

        buf_size = buf2_size = max_size + sector_size;

        base_pos = cvu64(sector_size * 3);

        if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        if ((buf2_ptr = alloc_contig(buf2_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        /* First establish a baseline. We need two requests for this, as the
         * total area intentionally exceeds the max request size.
         */
        if (may_write) {
                sum = fill_rand(buf_ptr, max_size);

                simple_xfer(driver_minor, base_pos, buf_ptr, max_size, TRUE,
                        max_size, &res);

                got_result(&res, "large baseline write");

                sum2 = fill_rand(buf_ptr + max_size, sector_size);

                simple_xfer(driver_minor, add64u(base_pos, max_size),
                        buf_ptr + max_size, sector_size, TRUE, sector_size,
                        &res);

                got_result(&res, "small baseline write");
        }

        fill_rand(buf_ptr, buf_size);

        simple_xfer(driver_minor, base_pos, buf_ptr, max_size, FALSE, max_size,
                &res);

        if (may_write)
                test_sum(buf_ptr, max_size, sum, TRUE, &res);

        got_result(&res, "large baseline read");

        simple_xfer(driver_minor, add64u(base_pos, max_size), buf_ptr +
                max_size, sector_size, FALSE, sector_size, &res);

        if (may_write)
                test_sum(buf_ptr + max_size, sector_size, sum2, TRUE, &res);

        got_result(&res, "small baseline read");

        /* First construct a full vector with minimal sizes. The resulting area
         * may well fall within a single sector, if min_read is small enough.
         */
        fill_rand(buf2_ptr, buf2_size);

        for (i = 0; i < NR_IOREQS; i++) {
                iov[i].iov_addr = (vir_bytes) buf2_ptr + i * sector_size;
                iov[i].iov_size = min_read;

                rsum[i] = get_sum(buf2_ptr + i * sector_size + min_read,
                        sector_size - min_read);
        }

        vir_xfer(driver_minor, add64u(base_pos, min_read), iov, NR_IOREQS,
                FALSE, min_read * NR_IOREQS, &res);

        for (i = 0; i < NR_IOREQS; i++) {
                test_sum(buf2_ptr + i * sector_size + min_read,
                        sector_size - min_read, rsum[i], TRUE, &res);
                memmove(buf2_ptr + i * min_read, buf2_ptr + i * sector_size,
                        min_read);
        }

        test_sum(buf2_ptr, min_read * NR_IOREQS, get_sum(buf_ptr + min_read,
                min_read * NR_IOREQS), TRUE, &res);

        got_result(&res, "small fully unaligned filled vector");

        /* Sneak in a maximum sized request with a single I/O vector element,
         * unaligned. If the driver splits up such large requests into smaller
         * chunks, this tests whether it does so correctly in the presence of
         * leads and trails.
         */
        fill_rand(buf2_ptr, buf2_size);

        simple_xfer(driver_minor, add64u(base_pos, min_read), buf2_ptr,
                max_size, FALSE, max_size, &res);

        test_sum(buf2_ptr, max_size, get_sum(buf_ptr + min_read, max_size),
                TRUE, &res);

        got_result(&res, "large fully unaligned single element");

        /* Then try with a vector where each element is as large as possible.
         * We don't have room to do bounds integrity checking here (we could
         * make room, but this may be a lot of memory already).
         */
        /* Compute the largest sector multiple which, when multiplied by
         * NR_IOREQS, is no more than the maximum transfer size.
         */
        max_block = max_size / NR_IOREQS;
        max_block -= max_block % sector_size;

        fill_rand(buf2_ptr, buf2_size);

        for (i = 0; i < NR_IOREQS; i++) {
                iov[i].iov_addr = (vir_bytes) buf2_ptr + i * max_block;
                iov[i].iov_size = max_block;
        }

        vir_xfer(driver_minor, add64u(base_pos, min_read), iov, NR_IOREQS,
                FALSE, max_block * NR_IOREQS, &res);

        test_sum(buf2_ptr, max_block * NR_IOREQS, get_sum(buf_ptr + min_read,
                max_block * NR_IOREQS), TRUE, &res);

        got_result(&res, "large fully unaligned filled vector");

        /* Clean up. */
        free_contig(buf2_ptr, buf2_size);
        free_contig(buf_ptr, buf_size);
}

static void sweep_area(u64_t base_pos)
{
        /* Go over an eight-sector area from left (low address) to right (high
         * address), reading and optionally writing in three-sector chunks, and
         * advancing one sector at a time.
         */
        u8_t *buf_ptr;
        size_t buf_size;
        u32_t sum = 0L, ssum[8];
        result_t res;
        int i, j;

        buf_size = sector_size * 8;

        if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                panic("unable to allocate memory");

        /* First (write to, if allowed, and) read from the entire area in one
         * go, so that we know the (initial) contents of the area.
         */
        if (may_write) {
                sum = fill_rand(buf_ptr, buf_size);

                simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, TRUE,
                        buf_size, &res);

                got_result(&res, "write to full area");
        }

        fill_rand(buf_ptr, buf_size);

        simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, FALSE, buf_size,
                &res);

        if (may_write)
                test_sum(buf_ptr, buf_size, sum, TRUE, &res);

        for (i = 0; i < 8; i++)
                ssum[i] = get_sum(buf_ptr + sector_size * i, sector_size);

        got_result(&res, "read from full area");

        /* For each of the six three-sector subareas, first read from the
         * subarea, check its checksum, and then (if allowed) write new content
         * to it.
         */
        for (i = 0; i < 6; i++) {
                fill_rand(buf_ptr, sector_size * 3);

                simple_xfer(driver_minor, add64u(base_pos, sector_size * i),
                        buf_ptr, sector_size * 3, FALSE, sector_size * 3,
                        &res);

                for (j = 0; j < 3; j++)
                        test_sum(buf_ptr + sector_size * j, sector_size,
                                ssum[i + j], TRUE, &res);

                got_result(&res, "read from subarea");

                if (!may_write)
                        continue;

                fill_rand(buf_ptr, sector_size * 3);

                simple_xfer(driver_minor, add64u(base_pos, sector_size * i),
                        buf_ptr, sector_size * 3, TRUE, sector_size * 3, &res);

                for (j = 0; j < 3; j++)
                        ssum[i + j] = get_sum(buf_ptr + sector_size * j,
                                sector_size);

                got_result(&res, "write to subarea");
        }

        /* Finally, if writing was enabled, do one final readback. */
        if (may_write) {
                fill_rand(buf_ptr, buf_size);

                simple_xfer(driver_minor, base_pos, buf_ptr, buf_size, FALSE,
                        buf_size, &res);

                for (i = 0; i < 8; i++)
                        test_sum(buf_ptr + sector_size * i, sector_size,
                                ssum[i], TRUE, &res);

                got_result(&res, "readback from full area");
        }

        /* Clean up. */
        free_contig(buf_ptr, buf_size);
}

static void sweep_and_check(u64_t pos, int check_integ)
{
        /* Perform an area sweep at the given position. If asked for, get an
         * integrity checksum over the beginning of the disk (first writing
         * known data into it if that is allowed) before doing the sweep, and
         * test the integrity checksum against the disk contents afterwards.
         */
        u8_t *buf_ptr;
        size_t buf_size;
        u32_t sum = 0L;
        result_t res;

        if (check_integ) {
                buf_size = sector_size * 3;

                if ((buf_ptr = alloc_contig(buf_size, 0, NULL)) == NULL)
                        panic("unable to allocate memory");

                if (may_write) {
                        sum = fill_rand(buf_ptr, buf_size);

                        simple_xfer(driver_minor, cvu64(0), buf_ptr, buf_size,
                                TRUE, buf_size, &res);

                        got_result(&res, "write integrity zone");
                }

                fill_rand(buf_ptr, buf_size);

                simple_xfer(driver_minor, cvu64(0), buf_ptr, buf_size, FALSE,
                        buf_size, &res);

                if (may_write)
                        test_sum(buf_ptr, buf_size, sum, TRUE, &res);
                else
                        sum = get_sum(buf_ptr, buf_size);

                got_result(&res, "read integrity zone");
        }

        sweep_area(pos);

        if (check_integ) {
                fill_rand(buf_ptr, buf_size);

                simple_xfer(driver_minor, cvu64(0), buf_ptr, buf_size, FALSE,
                        buf_size, &res);

                test_sum(buf_ptr, buf_size, sum, TRUE, &res);

                got_result(&res, "check integrity zone");

                free_contig(buf_ptr, buf_size);
        }
}

static void basic_sweep(void)
{
        /* Perform a basic area sweep.
         */

        test_group("basic area sweep", TRUE);

        sweep_area(cvu64(sector_size));
}

static void high_disk_pos(void)
{
        /* Test 64-bit absolute disk positions. This means that after adding
         * partition base to the given position, the driver will be dealing
         * with a position above 32 bit. We want to test the transition area
         * only; if the entire partition base is above 32 bit, we have already
         * effectively performed this test many times over. In other words, for
         * this test, the partition must start below 4GB and end above 4GB,
         * with at least four sectors on each side.
         */
        u64_t base_pos;

        base_pos = make64(sector_size * 4, 1L);
        base_pos = sub64u(base_pos, rem64u(base_pos, sector_size));

        /* The partition end must exceed 32 bits. */
        if (cmp64(add64(part.base, part.size), base_pos) < 0) {
                test_group("high disk positions", FALSE);

                return;
        }

        base_pos = sub64u(base_pos, sector_size * 8);

        /* The partition start must not. */
        if (cmp64(base_pos, part.base) < 0) {
                test_group("high disk positions", FALSE);
                return;
        }

        test_group("high disk positions", TRUE);

        base_pos = sub64(base_pos, part.base);

        sweep_and_check(base_pos, !cmp64u(part.base, 0));
}

static void high_part_pos(void)
{
        /* Test 64-bit partition-relative disk positions. In other words, use
         * within the current partition a position that exceeds a 32-bit value.
         * This requires the partition to be more than 4GB in size; we need an
         * additional 4 sectors, to be exact.
         */
        u64_t base_pos;

        /* If the partition starts at the beginning of the disk, this test is
         * no different from the high disk position test.
         */
        if (cmp64u(part.base, 0) == 0) {
                /* don't complain: the test is simply superfluous now */
                return;
        }

        base_pos = make64(sector_size * 4, 1L);
        base_pos = sub64u(base_pos, rem64u(base_pos, sector_size));

        if (cmp64(part.size, base_pos) < 0) {
                test_group("high partition positions", FALSE);

                return;
        }

        test_group("high partition positions", TRUE);

        base_pos = sub64u(base_pos, sector_size * 8);

        sweep_and_check(base_pos, TRUE);
}

static void high_lba_pos1(void)
{
        /* Test 48-bit LBA positions, as opposed to *24-bit*. Drivers that only
         * support 48-bit LBA ATA transfers, will treat the lower and upper 24
         * bits differently. This is again relative to the disk start, not the
         * partition start. For 512-byte sectors, the lowest position exceeding
         * 24 bit is at 8GB. As usual, we need four sectors more, and fewer, on
         * the other side. The partition that we're operating on, must cover
         * this area.
         */
        u64_t base_pos;

        base_pos = mul64u(1L << 24, sector_size);

        /* The partition end must exceed the 24-bit sector point. */
        if (cmp64(add64(part.base, part.size), base_pos) < 0) {
                test_group("high LBA positions, part one", FALSE);

                return;
        }

        base_pos = sub64u(base_pos, sector_size * 8);

        /* The partition start must not. */
        if (cmp64(base_pos, part.base) < 0) {
                test_group("high LBA positions, part one", FALSE);

                return;
        }

        test_group("high LBA positions, part one", TRUE);

        base_pos = sub64(base_pos, part.base);

        sweep_and_check(base_pos, !cmp64u(part.base, 0));
}

static void high_lba_pos2(void)
{
        /* Test 48-bit LBA positions, as opposed to *28-bit*. That means sector
         * numbers in excess of 28-bit values; the old ATA upper limit. The
         * same considerations as above apply, except that we now need a 128+GB
         * partition.
         */
        u64_t base_pos;

        base_pos = mul64u(1L << 28, sector_size);

        /* The partition end must exceed the 28-bit sector point. */
        if (cmp64(add64(part.base, part.size), base_pos) < 0) {
                test_group("high LBA positions, part two", FALSE);

                return;
        }

        base_pos = sub64u(base_pos, sector_size * 8);

        /* The partition start must not. */
        if (cmp64(base_pos, part.base) < 0) {
                test_group("high LBA positions, part two", FALSE);

                return;
        }

        test_group("high LBA positions, part two", TRUE);

        base_pos = sub64(base_pos, part.base);

        sweep_and_check(base_pos, !cmp64u(part.base, 0));
}

static void high_pos(void)
{
        /* Check whether the driver deals well with 64-bit positions and
         * 48-bit LBA addresses. We test three cases: disk byte position beyond
         * what fits in 32 bit, in-partition byte position beyond what fits in
         * 32 bit, and disk sector position beyond what fits in 24 bit. With
         * the partition we've been given, we may not be able to test all of
         * them (or any, for that matter).
         */
        /* In certain rare cases, we might be able to perform integrity
         * checking on the area that would be affected if a 32-bit/24-bit
         * counter were to wrap. More specifically: we can do that if we can
         * access the start of the disk. This is why we should be given the
         * entire disk as test area if at all possible.
         */

        basic_sweep();

        high_disk_pos();

        high_part_pos();

        high_lba_pos1();

        high_lba_pos2();
}

static void open_primary(void)
{
        /* Open the primary device. This call has its own test group.
         */

        test_group("device open", TRUE);

        open_device(driver_minor);
}

static void close_primary(void)
{
        /* Close the primary device. This call has its own test group.
         */

        test_group("device close", TRUE);

        close_device(driver_minor);

        assert(nr_opened == 0);
}

static void do_tests(void)
{
        /* Perform all the tests.
         */

        open_primary();

        misc_ioctl();

        bad_read1();

        bad_read2();

        /* It is assumed that the driver implementation uses shared
         * code paths for read and write for the basic checks, so we do
         * not repeat those for writes.
         */
        bad_write();

        vector_and_large();

        part_limits();

        unaligned_size();

        unaligned_pos1();

        unaligned_pos2();

        high_pos();

        close_primary();
}

static int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
{
        /* Initialize.
         */
        int r;
        clock_t now;

        if (env_argc > 1)
                optset_parse(optset_table, env_argv[1]);

        if (driver_label[0] == '\0')
                panic("no driver label given");

        if (ds_retrieve_label_endpt(driver_label, &driver_endpt))
                panic("unable to resolve driver label");

        if (driver_minor > 255)
                panic("invalid or no driver minor given");

        if ((r = getuptime(&now)) != OK)
                panic("unable to get uptime: %d", r);

        srand48(now);

        return OK;
}

static void sef_local_startup(void)
{
        /* Initialize the SEF framework.
         */

        sef_setcb_init_fresh(sef_cb_init_fresh);

        sef_startup();
}

int main(int argc, char **argv)
{
        /* Driver task.
         */

        env_setargs(argc, argv);
        sef_local_startup();

        printf("BLOCKTEST: driver label '%s' (endpt %d), minor %d\n",
                driver_label, driver_endpt, driver_minor);

        do_tests();

        printf("BLOCKTEST: summary: %d out of %d tests failed "
                "across %d group%s; %d driver deaths\n",
                failed_tests, total_tests, failed_groups,
                failed_groups == 1 ? "" : "s", driver_deaths);

        return 0;
}