scsi_ioctl.c

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/*
 * Changes:
 * Arnaldo Carvalho de Melo <[email protected]> 08/23/2000
 * - get rid of some verify_areas and use __copy*user and __get/put_user
 *   for the ones that remain
 */
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/sg.h>
#include <scsi/scsi_dbg.h>

#include "scsi_logging.h"

#define NORMAL_RETRIES          5
#define IOCTL_NORMAL_TIMEOUT            (10 * HZ)

#define MAX_BUF PAGE_SIZE

static int ioctl_probe(struct Scsi_Host *host, void __user *buffer)
{
    unsigned int len, slen;
    const char *string;

    if (buffer) {
        if (get_user(len, (unsigned int __user *) buffer))
            return -EFAULT;

        if (host->hostt->info)
            string = host->hostt->info(host);
        else
            string = host->hostt->name;
        if (string) {
            slen = strlen(string);
            if (len > slen)
                len = slen + 1;
            if (copy_to_user(buffer, string, len))
                return -EFAULT;
        }
    }
    return 1;
}

/*

 * The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
 * The IOCTL_NORMAL_TIMEOUT and NORMAL_RETRIES  variables are used.  
 * 
 * dev is the SCSI device struct ptr, *(int *) arg is the length of the
 * input data, if any, not including the command string & counts, 
 * *((int *)arg + 1) is the output buffer size in bytes.
 * 
 * *(char *) ((int *) arg)[2] the actual command byte.   
 * 
 * Note that if more than MAX_BUF bytes are requested to be transferred,
 * the ioctl will fail with error EINVAL.
 * 
 * This size *does not* include the initial lengths that were passed.
 * 
 * The SCSI command is read from the memory location immediately after the
 * length words, and the input data is right after the command.  The SCSI
 * routines know the command size based on the opcode decode.  
 * 
 * The output area is then filled in starting from the command byte. 
 */

static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
                  int timeout, int retries)
{
    int result;
    struct scsi_sense_hdr sshdr;

    SCSI_LOG_IOCTL(1, printk("Trying ioctl with scsi command %d\n", *cmd));

    result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0,
                  &sshdr, timeout, retries, NULL);

    SCSI_LOG_IOCTL(2, printk("Ioctl returned  0x%x\n", result));

    if ((driver_byte(result) & DRIVER_SENSE) &&
        (scsi_sense_valid(&sshdr))) {
        switch (sshdr.sense_key) {
        case ILLEGAL_REQUEST:
            if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
                sdev->lockable = 0;
            else
                printk(KERN_INFO "ioctl_internal_command: "
                       "ILLEGAL REQUEST asc=0x%x ascq=0x%x\n",
                       sshdr.asc, sshdr.ascq);
            break;
        case NOT_READY: /* This happens if there is no disc in drive */
            if (sdev->removable)
                break;
        case UNIT_ATTENTION:
            if (sdev->removable) {
                sdev->changed = 1;
                result = 0; /* This is no longer considered an error */
                break;
            }
        default:    /* Fall through for non-removable media */
            sdev_printk(KERN_INFO, sdev,
                    "ioctl_internal_command return code = %x\n",
                    result);
            scsi_print_sense_hdr("   ", &sshdr);
            break;
        }
    }

    SCSI_LOG_IOCTL(2, printk("IOCTL Releasing command\n"));
    return result;
}

int scsi_set_medium_removal(struct scsi_device *sdev, char state)
{
    char scsi_cmd[MAX_COMMAND_SIZE];
    int ret;

    if (!sdev->removable || !sdev->lockable)
           return 0;

    scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
    scsi_cmd[1] = 0;
    scsi_cmd[2] = 0;
    scsi_cmd[3] = 0;
    scsi_cmd[4] = state;
    scsi_cmd[5] = 0;

    ret = ioctl_internal_command(sdev, scsi_cmd,
            IOCTL_NORMAL_TIMEOUT, NORMAL_RETRIES);
    if (ret == 0)
        sdev->locked = (state == SCSI_REMOVAL_PREVENT);
    return ret;
}
EXPORT_SYMBOL(scsi_set_medium_removal);

/*
 * The scsi_ioctl_get_pci() function places into arg the value
 * pci_dev::slot_name (8 characters) for the PCI device (if any).
 * Returns: 0 on success
 *          -ENXIO if there isn't a PCI device pointer
 *                 (could be because the SCSI driver hasn't been
 *                  updated yet, or because it isn't a SCSI
 *                  device)
 *          any copy_to_user() error on failure there
 */
static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
{
    struct device *dev = scsi_get_device(sdev->host);
    const char *name;

        if (!dev)
        return -ENXIO;

    name = dev_name(dev);

    /* compatibility with old ioctl which only returned
     * 20 characters */
        return copy_to_user(arg, name, min(strlen(name), (size_t)20))
        ? -EFAULT: 0;
}


int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
{
    char scsi_cmd[MAX_COMMAND_SIZE];

    /* No idea how this happens.... */
    if (!sdev)
        return -ENXIO;

    /*
     * If we are in the middle of error recovery, don't let anyone
     * else try and use this device.  Also, if error recovery fails, it
     * may try and take the device offline, in which case all further
     * access to the device is prohibited.
     */
    if (!scsi_block_when_processing_errors(sdev))
        return -ENODEV;

    /* Check for deprecated ioctls ... all the ioctls which don't
     * follow the new unique numbering scheme are deprecated */
    switch (cmd) {
    case SCSI_IOCTL_SEND_COMMAND:
    case SCSI_IOCTL_TEST_UNIT_READY:
    case SCSI_IOCTL_BENCHMARK_COMMAND:
    case SCSI_IOCTL_SYNC:
    case SCSI_IOCTL_START_UNIT:
    case SCSI_IOCTL_STOP_UNIT:
        printk(KERN_WARNING "program %s is using a deprecated SCSI "
               "ioctl, please convert it to SG_IO\n", current->comm);
        break;
    default:
        break;
    }

    switch (cmd) {
    case SCSI_IOCTL_GET_IDLUN:
        if (!access_ok(VERIFY_WRITE, arg, sizeof(struct scsi_idlun)))
            return -EFAULT;

        __put_user((sdev->id & 0xff)
             + ((sdev->lun & 0xff) << 8)
             + ((sdev->channel & 0xff) << 16)
             + ((sdev->host->host_no & 0xff) << 24),
             &((struct scsi_idlun __user *)arg)->dev_id);
        __put_user(sdev->host->unique_id,
             &((struct scsi_idlun __user *)arg)->host_unique_id);
        return 0;
    case SCSI_IOCTL_GET_BUS_NUMBER:
        return put_user(sdev->host->host_no, (int __user *)arg);
    case SCSI_IOCTL_PROBE_HOST:
        return ioctl_probe(sdev->host, arg);
    case SCSI_IOCTL_SEND_COMMAND:
        if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
            return -EACCES;
        return sg_scsi_ioctl(sdev->request_queue, NULL, 0, arg);
    case SCSI_IOCTL_DOORLOCK:
        return scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
    case SCSI_IOCTL_DOORUNLOCK:
        return scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
    case SCSI_IOCTL_TEST_UNIT_READY:
        return scsi_test_unit_ready(sdev, IOCTL_NORMAL_TIMEOUT,
                        NORMAL_RETRIES, NULL);
    case SCSI_IOCTL_START_UNIT:
        scsi_cmd[0] = START_STOP;
        scsi_cmd[1] = 0;
        scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
        scsi_cmd[4] = 1;
        return ioctl_internal_command(sdev, scsi_cmd,
                     START_STOP_TIMEOUT, NORMAL_RETRIES);
    case SCSI_IOCTL_STOP_UNIT:
        scsi_cmd[0] = START_STOP;
        scsi_cmd[1] = 0;
        scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
        scsi_cmd[4] = 0;
        return ioctl_internal_command(sdev, scsi_cmd,
                     START_STOP_TIMEOUT, NORMAL_RETRIES);
        case SCSI_IOCTL_GET_PCI:
                return scsi_ioctl_get_pci(sdev, arg);
    default:
        if (sdev->host->hostt->ioctl)
            return sdev->host->hostt->ioctl(sdev, cmd, arg);
    }
    return -EINVAL;
}
EXPORT_SYMBOL(scsi_ioctl);

int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
                void __user *arg, int ndelay)
{
    int val, result;

    /* The first set of iocts may be executed even if we're doing
     * error processing, as long as the device was opened
     * non-blocking */
    if (ndelay) {
        if (scsi_host_in_recovery(sdev->host))
            return -ENODEV;
    } else if (!scsi_block_when_processing_errors(sdev))
        return -ENODEV;

    switch (cmd) {
    case SG_SCSI_RESET:
        result = get_user(val, (int __user *)arg);
        if (result)
            return result;
        if (val == SG_SCSI_RESET_NOTHING)
            return 0;
        switch (val) {
        case SG_SCSI_RESET_DEVICE:
            val = SCSI_TRY_RESET_DEVICE;
            break;
        case SG_SCSI_RESET_TARGET:
            val = SCSI_TRY_RESET_TARGET;
            break;
        case SG_SCSI_RESET_BUS:
            val = SCSI_TRY_RESET_BUS;
            break;
        case SG_SCSI_RESET_HOST:
            val = SCSI_TRY_RESET_HOST;
            break;
        default:
            return -EINVAL;
        }
        if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
            return -EACCES;
        return (scsi_reset_provider(sdev, val) ==
            SUCCESS) ? 0 : -EIO;
    }
    return -ENODEV;
}
EXPORT_SYMBOL(scsi_nonblockable_ioctl);