root/lib/libcam/camlib.c
/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1997, 1998, 1999, 2002 Kenneth D. Merry.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <ctype.h>

#include <cam/cam.h>
#include <cam/scsi/scsi_all.h>
#include <cam/cam_ccb.h>
#include <cam/scsi/scsi_pass.h>
#include "camlib.h"


static const char *nonrewind_devs[] = {
        "sa"
};

char cam_errbuf[CAM_ERRBUF_SIZE];

static struct cam_device *cam_real_open_device(const char *path, int flags,
                                               struct cam_device *device,
                                               const char *given_path,
                                               const char *given_dev_name,
                                               int given_unit_number);
static struct cam_device *cam_lookup_pass(const char *dev_name, int unit,
                                          int flags, const char *given_path,
                                          struct cam_device *device);

/*
 * Send a ccb to a passthrough device.
 */
int
cam_send_ccb(struct cam_device *device, union ccb *ccb)
{
        return(ioctl(device->fd, CAMIOCOMMAND, ccb));
}

/*
 * Malloc a CCB, zero out the header and set its path, target and lun ids.
 */
union ccb *
cam_getccb(struct cam_device *dev)
{
        union ccb *ccb;

        ccb = calloc(1, sizeof(*ccb));
        if (ccb != NULL) {
                ccb->ccb_h.path_id = dev->path_id;
                ccb->ccb_h.target_id = dev->target_id;
                ccb->ccb_h.target_lun = dev->target_lun;
        }

        return(ccb);
}

/*
 * Free a CCB.
 */
void
cam_freeccb(union ccb *ccb)
{
        free(ccb);
}

/*
 * Take a device name or path passed in by the user, and attempt to figure
 * out the device name and unit number.  Some possible device name formats are:
 * /dev/foo0
 * foo0
 * nfoo0
 *
 * Some peripheral drivers create separate device nodes with 'n' prefix for
 * non-rewind operations.  Currently only sa(4) tape driver has this feature.
 * We extract pure peripheral name as device name for this special case.
 *
 * Input parameters:  device name/path, length of devname string
 * Output:            device name, unit number
 * Return values:     returns 0 for success, -1 for failure
 */
int
cam_get_device(const char *path, char *dev_name, int devnamelen, int *unit)
{
        char *tmpstr, *tmpstr2;
        char *newpath;
        int unit_offset;
        int i;

        if (path == NULL) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: device pathname was NULL", __func__);
                return(-1);
        }

        /*
         * Resolve the given path to a real device path in case we are given
         * an alias or other symbolic link.  If the path cannot be resolved
         * then try to parse it as is.
         */
        newpath = realpath(path, NULL);
        if (newpath == NULL)
                newpath = strdup(path);
        if (newpath == NULL)
                return (-1);

        tmpstr = newpath;

        /*
         * Check to see whether we have an absolute pathname.
         */
        if (*tmpstr == '/') {
                tmpstr2 = tmpstr;
                tmpstr = strrchr(tmpstr2, '/');
                /* We know that tmpstr2 contains a '/', so strrchr can't fail */
                assert(tmpstr != NULL && *tmpstr != '\0');
                tmpstr++;
        }

        if (*tmpstr == '\0') {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: no text after slash", __func__);
                free(newpath);
                return(-1);
        }

        /*
         * Check to see whether the user has given us a nonrewound tape
         * device.
         */
        if (*tmpstr == 'n' || *tmpstr == 'e') {
                for (i = 0; i < sizeof(nonrewind_devs)/sizeof(char *); i++) {
                        int len = strlen(nonrewind_devs[i]);
                        if (strncmp(tmpstr + 1, nonrewind_devs[i], len) == 0) {
                                if (isdigit(tmpstr[len + 1])) {
                                        tmpstr++;
                                        break;
                                }
                        }
                }
        }

        /*
         * We should now have just a device name and unit number.
         * That means that there must be at least 2 characters.
         * If we only have 1, we don't have a valid device name.
         */
        if (strlen(tmpstr) < 2) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: must have both device name and unit number",
                    __func__);
                free(newpath);
                return(-1);
        }

        /*
         * If the first character of the string is a digit, then the user
         * has probably given us all numbers.  Point out the error.
         */
        if (isdigit(*tmpstr)) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: device name cannot begin with a number",
                    __func__);
                free(newpath);
                return(-1);
        }

        /*
         * At this point, if the last character of the string isn't a
         * number, we know the user either didn't give us a device number,
         * or he gave us a device name/number format we don't recognize.
         */
        if (!isdigit(tmpstr[strlen(tmpstr) - 1])) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: unable to find device unit number", __func__);
                free(newpath);
                return(-1);
        }

        /*
         * Attempt to figure out where the device name ends and the unit
         * number begins.  As long as unit_offset is at least 1 less than
         * the length of the string, we can still potentially have a device
         * name at the front of the string.  When we get to something that
         * isn't a digit, we've hit the device name.  Because of the check
         * above, we know that this cannot happen when unit_offset == 1.
         * Therefore it is okay to decrement unit_offset -- it won't cause
         * us to go past the end of the character array.
         */
        for (unit_offset = 1;
            (unit_offset < (strlen(tmpstr)))
            && (isdigit(tmpstr[strlen(tmpstr) - unit_offset])); unit_offset++);

        unit_offset--;

        /*
         * Grab the unit number.
         */
        *unit = atoi(&tmpstr[strlen(tmpstr) - unit_offset]);

        /*
         * Put a null in place of the first number of the unit number so
         * that all we have left is the device name.
         */
        tmpstr[strlen(tmpstr) - unit_offset] = '\0';

        strlcpy(dev_name, tmpstr, devnamelen);

        /* Clean up allocated memory */
        free(newpath);

        return(0);

}

/*
 * Backwards compatible wrapper for the real open routine.  This translates
 * a pathname into a device name and unit number for use with the real open
 * routine.
 */
struct cam_device *
cam_open_device(const char *path, int flags)
{
        int unit;
        char dev_name[DEV_IDLEN + 1];

        /*
         * cam_get_device() has already put an error message in cam_errbuf,
         * so we don't need to.
         */
        if (cam_get_device(path, dev_name, sizeof(dev_name), &unit) == -1)
                return(NULL);

        return(cam_lookup_pass(dev_name, unit, flags, path, NULL));
}

/*
 * Open the passthrough device for a given bus, target and lun, if the
 * passthrough device exists.
 */
struct cam_device *
cam_open_btl(path_id_t path_id, target_id_t target_id, lun_id_t target_lun,
             int flags, struct cam_device *device)
{
        union ccb ccb;
        struct periph_match_pattern *match_pat;
        int fd, bufsize;

        if ((fd = open(XPT_DEVICE, O_RDWR)) < 0) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: couldn't open %s\n%s: %s", __func__, XPT_DEVICE,
                    __func__, strerror(errno));
                return(NULL);
        }

        bzero(&ccb, sizeof(union ccb));
        ccb.ccb_h.func_code = XPT_DEV_MATCH;
        ccb.ccb_h.path_id = CAM_XPT_PATH_ID;
        ccb.ccb_h.target_id = CAM_TARGET_WILDCARD;
        ccb.ccb_h.target_lun = CAM_LUN_WILDCARD;

        /* Setup the result buffer */
        bufsize = sizeof(struct dev_match_result);
        ccb.cdm.match_buf_len = bufsize;
        ccb.cdm.matches = (struct dev_match_result *)malloc(bufsize);
        if (ccb.cdm.matches == NULL) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: couldn't malloc match buffer", __func__);
                close(fd);
                return(NULL);
        }
        ccb.cdm.num_matches = 0;

        /* Setup the pattern buffer */
        ccb.cdm.num_patterns = 1;
        ccb.cdm.pattern_buf_len = sizeof(struct dev_match_pattern);
        ccb.cdm.patterns = (struct dev_match_pattern *)malloc(
                sizeof(struct dev_match_pattern));
        if (ccb.cdm.patterns == NULL) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: couldn't malloc pattern buffer", __func__);
                free(ccb.cdm.matches);
                ccb.cdm.matches = NULL;
                close(fd);
                return(NULL);
        }
        ccb.cdm.patterns[0].type = DEV_MATCH_PERIPH;
        match_pat = &ccb.cdm.patterns[0].pattern.periph_pattern;

        /*
         * We're looking for the passthrough device associated with this
         * particular bus/target/lun.
         */
        sprintf(match_pat->periph_name, "pass");
        match_pat->path_id = path_id;
        match_pat->target_id = target_id;
        match_pat->target_lun = target_lun;
        /* Now set the flags to indicate what we're looking for. */
        match_pat->flags = PERIPH_MATCH_PATH | PERIPH_MATCH_TARGET |
                           PERIPH_MATCH_LUN | PERIPH_MATCH_NAME;

        if (ioctl(fd, CAMIOCOMMAND, &ccb) == -1) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: CAMIOCOMMAND ioctl failed\n"
                    "%s: %s", __func__, __func__, strerror(errno));
                goto btl_bailout;
        }

        /*
         * Check for an outright error.
         */
        if ((ccb.ccb_h.status != CAM_REQ_CMP)
         || ((ccb.cdm.status != CAM_DEV_MATCH_LAST)
           && (ccb.cdm.status != CAM_DEV_MATCH_MORE))) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: CAM error %#x, CDM error %d "
                    "returned from XPT_DEV_MATCH ccb", __func__,
                    ccb.ccb_h.status, ccb.cdm.status);
                goto btl_bailout;
        }

        if (ccb.cdm.status == CAM_DEV_MATCH_MORE) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: CDM reported more than one"
                    " passthrough device at %d:%d:%jx!!\n",
                    __func__, path_id, target_id, (uintmax_t)target_lun);
                goto btl_bailout;
        }

        if (ccb.cdm.num_matches == 0) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: no passthrough device found at"
                    " %d:%d:%jx", __func__, path_id, target_id,
                    (uintmax_t)target_lun);
                goto btl_bailout;
        }

        switch(ccb.cdm.matches[0].type) {
        case DEV_MATCH_PERIPH: {
                int pass_unit;
                char dev_path[256];
                struct periph_match_result *periph_result;

                periph_result = &ccb.cdm.matches[0].result.periph_result;
                pass_unit = periph_result->unit_number;
                free(ccb.cdm.matches);
                ccb.cdm.matches = NULL;
                free(ccb.cdm.patterns);
                ccb.cdm.patterns = NULL;
                close(fd);
                sprintf(dev_path, "/dev/pass%d", pass_unit);
                return(cam_real_open_device(dev_path, flags, device, NULL,
                                            NULL, 0));
                break; /* NOTREACHED */
        }
        default:
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: asked for a peripheral match, but"
                    " got a bus or device match", __func__);
                goto btl_bailout;
                break; /* NOTREACHED */
        }

btl_bailout:
        free(ccb.cdm.matches);
        ccb.cdm.matches = NULL;
        free(ccb.cdm.patterns);
        ccb.cdm.patterns = NULL;
        close(fd);
        return(NULL);
}

struct cam_device *
cam_open_spec_device(const char *dev_name, int unit, int flags,
                     struct cam_device *device)
{
        return(cam_lookup_pass(dev_name, unit, flags, NULL, device));
}

struct cam_device *
cam_open_pass(const char *path, int flags, struct cam_device *device)
{
        return(cam_real_open_device(path, flags, device, path, NULL, 0));
}

static struct cam_device *
cam_lookup_pass(const char *dev_name, int unit, int flags,
                const char *given_path, struct cam_device *device)
{
        int fd;
        union ccb ccb;
        char dev_path[256];

        /*
         * The flags argument above only applies to the actual passthrough
         * device open, not our open of the given device to find the
         * passthrough device.
         */
        if ((fd = open(XPT_DEVICE, O_RDWR)) < 0) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: couldn't open %s\n%s: %s", __func__, XPT_DEVICE,
                    __func__, strerror(errno));
                return(NULL);
        }

        /* This isn't strictly necessary for the GETPASSTHRU ioctl. */
        ccb.ccb_h.func_code = XPT_GDEVLIST;

        /* These two are necessary for the GETPASSTHRU ioctl to work. */
        strlcpy(ccb.cgdl.periph_name, dev_name, sizeof(ccb.cgdl.periph_name));
        ccb.cgdl.unit_number = unit;

        /*
         * Attempt to get the passthrough device.  This ioctl will fail if
         * the device name is null, if the device doesn't exist, or if the
         * passthrough driver isn't in the kernel.
         */
        if (ioctl(fd, CAMGETPASSTHRU, &ccb) == -1) {
                char tmpstr[256];

                /*
                 * If we get ENOENT from the transport layer version of
                 * the CAMGETPASSTHRU ioctl, it means one of two things:
                 * either the device name/unit number passed in doesn't
                 * exist, or the passthrough driver isn't in the kernel.
                 */
                if (errno == ENOENT) {
                        snprintf(tmpstr, sizeof(tmpstr),
                                 "\n%s: either the pass driver isn't in "
                                 "your kernel\n%s: or %s%d doesn't exist",
                                 __func__, __func__, dev_name, unit);
                }
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: CAMGETPASSTHRU ioctl failed\n"
                    "%s: %s%s", __func__, __func__, strerror(errno),
                    (errno == ENOENT) ? tmpstr : "");

                close(fd);
                return(NULL);
        }

        close(fd);

        /*
         * If the ioctl returned the right status, but we got an error back
         * in the ccb, that means that the kernel found the device the user
         * passed in, but was unable to find the passthrough device for
         * the device the user gave us.
         */
        if (ccb.cgdl.status == CAM_GDEVLIST_ERROR) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: device %s%d does not exist!",
                    __func__, dev_name, unit);
                return(NULL);
        }

        sprintf(dev_path, "/dev/%s%d", ccb.cgdl.periph_name,
                ccb.cgdl.unit_number);

        return(cam_real_open_device(dev_path, flags, device, NULL,
                                    dev_name, unit));
}

/*
 * Open a given device.  The path argument isn't strictly necessary, but it
 * is copied into the cam_device structure as a convenience to the user.
 */
static struct cam_device *
cam_real_open_device(const char *path, int flags, struct cam_device *device,
                     const char *given_path, const char *given_dev_name,
                     int given_unit_number)
{
        union ccb ccb;
        int fd = -1, malloced_device = 0;

        /*
         * See if the user wants us to malloc a device for him.
         */
        if (device == NULL) {
                if ((device = (struct cam_device *)malloc(
                     sizeof(struct cam_device))) == NULL) {
                        snprintf(cam_errbuf, nitems(cam_errbuf),
                            "%s: device structure malloc"
                            " failed\n%s: %s", __func__, __func__,
                            strerror(errno));
                        return(NULL);
                }
                device->fd = -1;
                malloced_device = 1;
        }

        /*
         * If the user passed in a path, save it for him.
         */
        if (given_path != NULL)
                strlcpy(device->device_path, given_path,
                        sizeof(device->device_path));
        else
                device->device_path[0] = '\0';

        /*
         * If the user passed in a device name and unit number pair, save
         * those as well.
         */
        if (given_dev_name != NULL)
                strlcpy(device->given_dev_name, given_dev_name,
                        sizeof(device->given_dev_name));
        else
                device->given_dev_name[0] = '\0';
        device->given_unit_number = given_unit_number;

        if ((fd = open(path, flags)) < 0) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: couldn't open passthrough device %s\n"
                    "%s: %s", __func__, path, __func__,
                    strerror(errno));
                goto crod_bailout;
        }

        device->fd = fd;

        bzero(&ccb, sizeof(union ccb));

        /*
         * Unlike the transport layer version of the GETPASSTHRU ioctl,
         * we don't have to set any fields.
         */
        ccb.ccb_h.func_code = XPT_GDEVLIST;

        /*
         * We're only doing this to get some information on the device in
         * question.  Otherwise, we'd have to pass in yet another
         * parameter: the passthrough driver unit number.
         */
        if (ioctl(fd, CAMGETPASSTHRU, &ccb) == -1) {
                /*
                 * At this point we know the passthrough device must exist
                 * because we just opened it above.  The only way this
                 * ioctl can fail is if the ccb size is wrong.
                 */
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: CAMGETPASSTHRU ioctl failed\n"
                    "%s: %s", __func__, __func__, strerror(errno));
                goto crod_bailout;
        }

        /*
         * If the ioctl returned the right status, but we got an error back
         * in the ccb, that means that the kernel found the device the user
         * passed in, but was unable to find the passthrough device for
         * the device the user gave us.
         */
        if (ccb.cgdl.status == CAM_GDEVLIST_ERROR) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: passthrough device does not exist!", __func__);
                goto crod_bailout;
        }

        device->dev_unit_num = ccb.cgdl.unit_number;
        strlcpy(device->device_name, ccb.cgdl.periph_name,
                sizeof(device->device_name));
        device->path_id = ccb.ccb_h.path_id;
        device->target_id = ccb.ccb_h.target_id;
        device->target_lun = ccb.ccb_h.target_lun;

        ccb.ccb_h.func_code = XPT_PATH_INQ;
        if (ioctl(fd, CAMIOCOMMAND, &ccb) == -1) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: Path Inquiry CCB failed\n"
                    "%s: %s", __func__, __func__, strerror(errno));
                goto crod_bailout;
        }
        strlcpy(device->sim_name, ccb.cpi.dev_name, sizeof(device->sim_name));
        device->sim_unit_number = ccb.cpi.unit_number;
        device->bus_id = ccb.cpi.bus_id;

        /*
         * It doesn't really matter what is in the payload for a getdev
         * CCB, the kernel doesn't look at it.
         */
        ccb.ccb_h.func_code = XPT_GDEV_TYPE;
        if (ioctl(fd, CAMIOCOMMAND, &ccb) == -1) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: Get Device Type CCB failed\n"
                    "%s: %s", __func__, __func__, strerror(errno));
                goto crod_bailout;
        }
        device->pd_type = SID_TYPE(&ccb.cgd.inq_data);
        bcopy(&ccb.cgd.inq_data, &device->inq_data,
              sizeof(struct scsi_inquiry_data));
        device->serial_num_len = ccb.cgd.serial_num_len;
        bcopy(&ccb.cgd.serial_num, &device->serial_num, device->serial_num_len);

        /*
         * Zero the payload, the kernel does look at the flags.
         */
        CCB_CLEAR_ALL_EXCEPT_HDR(&ccb.cts);

        /*
         * Get transfer settings for this device.
         */
        ccb.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;

        ccb.cts.type = CTS_TYPE_CURRENT_SETTINGS;

        if (ioctl(fd, CAMIOCOMMAND, &ccb) == -1) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: Get Transfer Settings CCB failed\n"
                    "%s: %s", __func__, __func__, strerror(errno));
                goto crod_bailout;
        }
        if (ccb.cts.transport == XPORT_SPI) {
                struct ccb_trans_settings_spi *spi =
                    &ccb.cts.xport_specific.spi;
                device->sync_period = spi->sync_period;
                device->sync_offset = spi->sync_offset;
                device->bus_width = spi->bus_width;
        } else {
                device->sync_period = 0;
                device->sync_offset = 0;
                device->bus_width = 0;
        }

        return(device);

crod_bailout:

        if (fd >= 0)
                close(fd);

        if (malloced_device)
                free(device);

        return(NULL);
}

void
cam_close_device(struct cam_device *dev)
{
        if (dev == NULL)
                return;

        cam_close_spec_device(dev);

        free(dev);
}

void
cam_close_spec_device(struct cam_device *dev)
{
        if (dev == NULL)
                return;

        if (dev->fd >= 0) {
                close(dev->fd);
                dev->fd = -1;
        }
}

char *
cam_path_string(struct cam_device *dev, char *str, int len)
{
        if (dev == NULL) {
                snprintf(str, len, "No path");
                return(str);
        }

        snprintf(str, len, "(%s%d:%s%d:%d:%d:%jx): ",
                 (dev->device_name[0] != '\0') ? dev->device_name : "pass",
                 dev->dev_unit_num,
                 (dev->sim_name[0] != '\0') ? dev->sim_name : "unknown",
                 dev->sim_unit_number,
                 dev->bus_id,
                 dev->target_id,
                 (uintmax_t)dev->target_lun);

        return(str);
}

/*
 * Malloc/duplicate a CAM device structure.
 */
struct cam_device *
cam_device_dup(struct cam_device *device)
{
        struct cam_device *newdev;

        if (device == NULL) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: device is NULL", __func__);
                return (NULL);
        }

        newdev = malloc(sizeof(struct cam_device));
        if (newdev == NULL) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: couldn't malloc CAM device structure", __func__);
                return (NULL);
        }

        bcopy(device, newdev, sizeof(struct cam_device));

        return(newdev);
}

/*
 * Copy a CAM device structure.
 */
void
cam_device_copy(struct cam_device *src, struct cam_device *dst)
{

        if (src == NULL) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: source device struct was NULL", __func__);
                return;
        }

        if (dst == NULL) {
                snprintf(cam_errbuf, nitems(cam_errbuf),
                    "%s: destination device struct was NULL", __func__);
                return;
        }

        bcopy(src, dst, sizeof(struct cam_device));

}