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scsi_ioctl.c

/*
 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 *
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/cdrom.h>
#include <linux/slab.h>
#include <linux/times.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsi_cmnd.h>

/* Command group 3 is reserved and should never be used.  */
const unsigned char scsi_command_size[8] =
{
      6, 10, 10, 12,
      16, 12, 10, 10
};

EXPORT_SYMBOL(scsi_command_size);

#include <scsi/sg.h>

static int sg_get_version(int __user *p)
{
      static const int sg_version_num = 30527;
      return put_user(sg_version_num, p);
}

static int scsi_get_idlun(struct request_queue *q, int __user *p)
{
      return put_user(0, p);
}

static int scsi_get_bus(struct request_queue *q, int __user *p)
{
      return put_user(0, p);
}

static int sg_get_timeout(struct request_queue *q)
{
      return q->sg_timeout / (HZ / USER_HZ);
}

static int sg_set_timeout(struct request_queue *q, int __user *p)
{
      int timeout, err = get_user(timeout, p);

      if (!err)
            q->sg_timeout = timeout * (HZ / USER_HZ);

      return err;
}

static int sg_get_reserved_size(struct request_queue *q, int __user *p)
{
      unsigned val = min(q->sg_reserved_size, q->max_sectors << 9);

      return put_user(val, p);
}

static int sg_set_reserved_size(struct request_queue *q, int __user *p)
{
      int size, err = get_user(size, p);

      if (err)
            return err;

      if (size < 0)
            return -EINVAL;
      if (size > (q->max_sectors << 9))
            size = q->max_sectors << 9;

      q->sg_reserved_size = size;
      return 0;
}

/*
 * will always return that we are ATAPI even for a real SCSI drive, I'm not
 * so sure this is worth doing anything about (why would you care??)
 */
static int sg_emulated_host(struct request_queue *q, int __user *p)
{
      return put_user(1, p);
}

#define CMD_READ_SAFE   0x01
#define CMD_WRITE_SAFE  0x02
#define CMD_WARNED      0x04
#define safe_for_read(cmd)    [cmd] = CMD_READ_SAFE
#define safe_for_write(cmd)   [cmd] = CMD_WRITE_SAFE

int blk_verify_command(unsigned char *cmd, int has_write_perm)
{
      static unsigned char cmd_type[256] = {

            /* Basic read-only commands */
            safe_for_read(TEST_UNIT_READY),
            safe_for_read(REQUEST_SENSE),
            safe_for_read(READ_6),
            safe_for_read(READ_10),
            safe_for_read(READ_12),
            safe_for_read(READ_16),
            safe_for_read(READ_BUFFER),
            safe_for_read(READ_DEFECT_DATA),
            safe_for_read(READ_LONG),
            safe_for_read(INQUIRY),
            safe_for_read(MODE_SENSE),
            safe_for_read(MODE_SENSE_10),
            safe_for_read(LOG_SENSE),
            safe_for_read(START_STOP),
            safe_for_read(GPCMD_VERIFY_10),
            safe_for_read(VERIFY_16),

            /* Audio CD commands */
            safe_for_read(GPCMD_PLAY_CD),
            safe_for_read(GPCMD_PLAY_AUDIO_10),
            safe_for_read(GPCMD_PLAY_AUDIO_MSF),
            safe_for_read(GPCMD_PLAY_AUDIO_TI),
            safe_for_read(GPCMD_PAUSE_RESUME),

            /* CD/DVD data reading */
            safe_for_read(GPCMD_READ_BUFFER_CAPACITY),
            safe_for_read(GPCMD_READ_CD),
            safe_for_read(GPCMD_READ_CD_MSF),
            safe_for_read(GPCMD_READ_DISC_INFO),
            safe_for_read(GPCMD_READ_CDVD_CAPACITY),
            safe_for_read(GPCMD_READ_DVD_STRUCTURE),
            safe_for_read(GPCMD_READ_HEADER),
            safe_for_read(GPCMD_READ_TRACK_RZONE_INFO),
            safe_for_read(GPCMD_READ_SUBCHANNEL),
            safe_for_read(GPCMD_READ_TOC_PMA_ATIP),
            safe_for_read(GPCMD_REPORT_KEY),
            safe_for_read(GPCMD_SCAN),
            safe_for_read(GPCMD_GET_CONFIGURATION),
            safe_for_read(GPCMD_READ_FORMAT_CAPACITIES),
            safe_for_read(GPCMD_GET_EVENT_STATUS_NOTIFICATION),
            safe_for_read(GPCMD_GET_PERFORMANCE),
            safe_for_read(GPCMD_SEEK),
            safe_for_read(GPCMD_STOP_PLAY_SCAN),

            /* Basic writing commands */
            safe_for_write(WRITE_6),
            safe_for_write(WRITE_10),
            safe_for_write(WRITE_VERIFY),
            safe_for_write(WRITE_12),
            safe_for_write(WRITE_VERIFY_12),
            safe_for_write(WRITE_16),
            safe_for_write(WRITE_LONG),
            safe_for_write(WRITE_LONG_2),
            safe_for_write(ERASE),
            safe_for_write(GPCMD_MODE_SELECT_10),
            safe_for_write(MODE_SELECT),
            safe_for_write(LOG_SELECT),
            safe_for_write(GPCMD_BLANK),
            safe_for_write(GPCMD_CLOSE_TRACK),
            safe_for_write(GPCMD_FLUSH_CACHE),
            safe_for_write(GPCMD_FORMAT_UNIT),
            safe_for_write(GPCMD_REPAIR_RZONE_TRACK),
            safe_for_write(GPCMD_RESERVE_RZONE_TRACK),
            safe_for_write(GPCMD_SEND_DVD_STRUCTURE),
            safe_for_write(GPCMD_SEND_EVENT),
            safe_for_write(GPCMD_SEND_KEY),
            safe_for_write(GPCMD_SEND_OPC),
            safe_for_write(GPCMD_SEND_CUE_SHEET),
            safe_for_write(GPCMD_SET_SPEED),
            safe_for_write(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL),
            safe_for_write(GPCMD_LOAD_UNLOAD),
            safe_for_write(GPCMD_SET_STREAMING),
      };
      unsigned char type = cmd_type[cmd[0]];

      /* Anybody who can open the device can do a read-safe command */
      if (type & CMD_READ_SAFE)
            return 0;

      /* Write-safe commands just require a writable open.. */
      if ((type & CMD_WRITE_SAFE) && has_write_perm)
            return 0;

      /* And root can do any command.. */
      if (capable(CAP_SYS_RAWIO))
            return 0;

      if (!type) {
            cmd_type[cmd[0]] = CMD_WARNED;
            printk(KERN_WARNING "scsi: unknown opcode 0x%02x\n", cmd[0]);
      }

      /* Otherwise fail it with an "Operation not permitted" */
      return -EPERM;
}
EXPORT_SYMBOL_GPL(blk_verify_command);

static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq,
                       struct sg_io_hdr *hdr, int has_write_perm)
{
      memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */

      if (copy_from_user(rq->cmd, hdr->cmdp, hdr->cmd_len))
            return -EFAULT;
      if (blk_verify_command(rq->cmd, has_write_perm))
            return -EPERM;

      /*
       * fill in request structure
       */
      rq->cmd_len = hdr->cmd_len;
      rq->cmd_type = REQ_TYPE_BLOCK_PC;

      rq->timeout = msecs_to_jiffies(hdr->timeout);
      if (!rq->timeout)
            rq->timeout = q->sg_timeout;
      if (!rq->timeout)
            rq->timeout = BLK_DEFAULT_SG_TIMEOUT;

      return 0;
}

/*
 * unmap a request that was previously mapped to this sg_io_hdr. handles
 * both sg and non-sg sg_io_hdr.
 */
static int blk_unmap_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr)
{
      blk_rq_unmap_user(rq->bio);
      blk_put_request(rq);
      return 0;
}

static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
                         struct bio *bio)
{
      int r, ret = 0;

      /*
       * fill in all the output members
       */
      hdr->status = rq->errors & 0xff;
      hdr->masked_status = status_byte(rq->errors);
      hdr->msg_status = msg_byte(rq->errors);
      hdr->host_status = host_byte(rq->errors);
      hdr->driver_status = driver_byte(rq->errors);
      hdr->info = 0;
      if (hdr->masked_status || hdr->host_status || hdr->driver_status)
            hdr->info |= SG_INFO_CHECK;
      hdr->resid = rq->data_len;
      hdr->sb_len_wr = 0;

      if (rq->sense_len && hdr->sbp) {
            int len = min((unsigned int) hdr->mx_sb_len, rq->sense_len);

            if (!copy_to_user(hdr->sbp, rq->sense, len))
                  hdr->sb_len_wr = len;
            else
                  ret = -EFAULT;
      }

      rq->bio = bio;
      r = blk_unmap_sghdr_rq(rq, hdr);
      if (ret)
            r = ret;

      return r;
}

static int sg_io(struct file *file, struct request_queue *q,
            struct gendisk *bd_disk, struct sg_io_hdr *hdr)
{
      unsigned long start_time;
      int writing = 0, ret = 0, has_write_perm = 0;
      struct request *rq;
      char sense[SCSI_SENSE_BUFFERSIZE];
      struct bio *bio;

      if (hdr->interface_id != 'S')
            return -EINVAL;
      if (hdr->cmd_len > BLK_MAX_CDB)
            return -EINVAL;

      if (hdr->dxfer_len > (q->max_hw_sectors << 9))
            return -EIO;

      if (hdr->dxfer_len)
            switch (hdr->dxfer_direction) {
            default:
                  return -EINVAL;
            case SG_DXFER_TO_DEV:
                  writing = 1;
                  break;
            case SG_DXFER_TO_FROM_DEV:
            case SG_DXFER_FROM_DEV:
                  break;
            }

      rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
      if (!rq)
            return -ENOMEM;

      if (file)
            has_write_perm = file->f_mode & FMODE_WRITE;

      if (blk_fill_sghdr_rq(q, rq, hdr, has_write_perm)) {
            blk_put_request(rq);
            return -EFAULT;
      }

      if (hdr->iovec_count) {
            const int size = sizeof(struct sg_iovec) * hdr->iovec_count;
            struct sg_iovec *iov;

            iov = kmalloc(size, GFP_KERNEL);
            if (!iov) {
                  ret = -ENOMEM;
                  goto out;
            }

            if (copy_from_user(iov, hdr->dxferp, size)) {
                  kfree(iov);
                  ret = -EFAULT;
                  goto out;
            }

            ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count,
                                hdr->dxfer_len);
            kfree(iov);
      } else if (hdr->dxfer_len)
            ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);

      if (ret)
            goto out;

      bio = rq->bio;
      memset(sense, 0, sizeof(sense));
      rq->sense = sense;
      rq->sense_len = 0;
      rq->retries = 0;

      start_time = jiffies;

      /* ignore return value. All information is passed back to caller
       * (if he doesn't check that is his problem).
       * N.B. a non-zero SCSI status is _not_ necessarily an error.
       */
      blk_execute_rq(q, bd_disk, rq, 0);

      hdr->duration = jiffies_to_msecs(jiffies - start_time);

      return blk_complete_sghdr_rq(rq, hdr, bio);
out:
      blk_put_request(rq);
      return ret;
}

/**
 * sg_scsi_ioctl  --  handle deprecated SCSI_IOCTL_SEND_COMMAND ioctl
 * @file:   file this ioctl operates on (optional)
 * @q:            request queue to send scsi commands down
 * @disk:   gendisk to operate on (option)
 * @sic:    userspace structure describing the command to perform
 *
 * Send down the scsi command described by @sic to the device below
 * the request queue @q.  If @file is non-NULL it's used to perform
 * fine-grained permission checks that allow users to send down
 * non-destructive SCSI commands.  If the caller has a struct gendisk
 * available it should be passed in as @disk to allow the low level
 * driver to use the information contained in it.  A non-NULL @disk
 * is only allowed if the caller knows that the low level driver doesn't
 * need it (e.g. in the scsi subsystem).
 *
 * Notes:
 *   -  This interface is deprecated - users should use the SG_IO
 *      interface instead, as this is a more flexible approach to
 *      performing SCSI commands on a device.
 *   -  The SCSI command length is determined by examining the 1st byte
 *      of the given command. There is no way to override this.
 *   -  Data transfers are limited to PAGE_SIZE
 *   -  The length (x + y) must be at least OMAX_SB_LEN bytes long to
 *      accommodate the sense buffer when an error occurs.
 *      The sense buffer is truncated to OMAX_SB_LEN (16) bytes so that
 *      old code will not be surprised.
 *   -  If a Unix error occurs (e.g. ENOMEM) then the user will receive
 *      a negative return and the Unix error code in 'errno'.
 *      If the SCSI command succeeds then 0 is returned.
 *      Positive numbers returned are the compacted SCSI error codes (4
 *      bytes in one int) where the lowest byte is the SCSI status.
 */
#define OMAX_SB_LEN 16          /* For backward compatibility */
int sg_scsi_ioctl(struct file *file, struct request_queue *q,
              struct gendisk *disk, struct scsi_ioctl_command __user *sic)
{
      struct request *rq;
      int err;
      unsigned int in_len, out_len, bytes, opcode, cmdlen;
      char *buffer = NULL, sense[SCSI_SENSE_BUFFERSIZE];

      if (!sic)
            return -EINVAL;

      /*
       * get in an out lengths, verify they don't exceed a page worth of data
       */
      if (get_user(in_len, &sic->inlen))
            return -EFAULT;
      if (get_user(out_len, &sic->outlen))
            return -EFAULT;
      if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
            return -EINVAL;
      if (get_user(opcode, sic->data))
            return -EFAULT;

      bytes = max(in_len, out_len);
      if (bytes) {
            buffer = kzalloc(bytes, q->bounce_gfp | GFP_USER| __GFP_NOWARN);
            if (!buffer)
                  return -ENOMEM;

      }

      rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);

      cmdlen = COMMAND_SIZE(opcode);

      /*
       * get command and data to send to device, if any
       */
      err = -EFAULT;
      rq->cmd_len = cmdlen;
      if (copy_from_user(rq->cmd, sic->data, cmdlen))
            goto error;

      if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
            goto error;

      err = blk_verify_command(rq->cmd, file->f_mode & FMODE_WRITE);
      if (err)
            goto error;

      /* default.  possible overriden later */
      rq->retries = 5;

      switch (opcode) {
      case SEND_DIAGNOSTIC:
      case FORMAT_UNIT:
            rq->timeout = FORMAT_UNIT_TIMEOUT;
            rq->retries = 1;
            break;
      case START_STOP:
            rq->timeout = START_STOP_TIMEOUT;
            break;
      case MOVE_MEDIUM:
            rq->timeout = MOVE_MEDIUM_TIMEOUT;
            break;
      case READ_ELEMENT_STATUS:
            rq->timeout = READ_ELEMENT_STATUS_TIMEOUT;
            break;
      case READ_DEFECT_DATA:
            rq->timeout = READ_DEFECT_DATA_TIMEOUT;
            rq->retries = 1;
            break;
      default:
            rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
            break;
      }

      if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_WAIT)) {
            err = DRIVER_ERROR << 24;
            goto out;
      }

      memset(sense, 0, sizeof(sense));
      rq->sense = sense;
      rq->sense_len = 0;
      rq->cmd_type = REQ_TYPE_BLOCK_PC;

      blk_execute_rq(q, disk, rq, 0);

out:
      err = rq->errors & 0xff;      /* only 8 bit SCSI status */
      if (err) {
            if (rq->sense_len && rq->sense) {
                  bytes = (OMAX_SB_LEN > rq->sense_len) ?
                        rq->sense_len : OMAX_SB_LEN;
                  if (copy_to_user(sic->data, rq->sense, bytes))
                        err = -EFAULT;
            }
      } else {
            if (copy_to_user(sic->data, buffer, out_len))
                  err = -EFAULT;
      }
      
error:
      kfree(buffer);
      blk_put_request(rq);
      return err;
}
EXPORT_SYMBOL_GPL(sg_scsi_ioctl);

/* Send basic block requests */
static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
                        int cmd, int data)
{
      struct request *rq;
      int err;

      rq = blk_get_request(q, WRITE, __GFP_WAIT);
      rq->cmd_type = REQ_TYPE_BLOCK_PC;
      rq->data = NULL;
      rq->data_len = 0;
      rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
      memset(rq->cmd, 0, sizeof(rq->cmd));
      rq->cmd[0] = cmd;
      rq->cmd[4] = data;
      rq->cmd_len = 6;
      err = blk_execute_rq(q, bd_disk, rq, 0);
      blk_put_request(rq);

      return err;
}

static inline int blk_send_start_stop(struct request_queue *q,
                              struct gendisk *bd_disk, int data)
{
      return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data);
}

int scsi_cmd_ioctl(struct file *file, struct request_queue *q,
               struct gendisk *bd_disk, unsigned int cmd, void __user *arg)
{
      int err;

      if (!q || blk_get_queue(q))
            return -ENXIO;

      switch (cmd) {
            /*
             * new sgv3 interface
             */
            case SG_GET_VERSION_NUM:
                  err = sg_get_version(arg);
                  break;
            case SCSI_IOCTL_GET_IDLUN:
                  err = scsi_get_idlun(q, arg);
                  break;
            case SCSI_IOCTL_GET_BUS_NUMBER:
                  err = scsi_get_bus(q, arg);
                  break;
            case SG_SET_TIMEOUT:
                  err = sg_set_timeout(q, arg);
                  break;
            case SG_GET_TIMEOUT:
                  err = sg_get_timeout(q);
                  break;
            case SG_GET_RESERVED_SIZE:
                  err = sg_get_reserved_size(q, arg);
                  break;
            case SG_SET_RESERVED_SIZE:
                  err = sg_set_reserved_size(q, arg);
                  break;
            case SG_EMULATED_HOST:
                  err = sg_emulated_host(q, arg);
                  break;
            case SG_IO: {
                  struct sg_io_hdr hdr;

                  err = -EFAULT;
                  if (copy_from_user(&hdr, arg, sizeof(hdr)))
                        break;
                  err = sg_io(file, q, bd_disk, &hdr);
                  if (err == -EFAULT)
                        break;

                  if (copy_to_user(arg, &hdr, sizeof(hdr)))
                        err = -EFAULT;
                  break;
            }
            case CDROM_SEND_PACKET: {
                  struct cdrom_generic_command cgc;
                  struct sg_io_hdr hdr;

                  err = -EFAULT;
                  if (copy_from_user(&cgc, arg, sizeof(cgc)))
                        break;
                  cgc.timeout = clock_t_to_jiffies(cgc.timeout);
                  memset(&hdr, 0, sizeof(hdr));
                  hdr.interface_id = 'S';
                  hdr.cmd_len = sizeof(cgc.cmd);
                  hdr.dxfer_len = cgc.buflen;
                  err = 0;
                  switch (cgc.data_direction) {
                        case CGC_DATA_UNKNOWN:
                              hdr.dxfer_direction = SG_DXFER_UNKNOWN;
                              break;
                        case CGC_DATA_WRITE:
                              hdr.dxfer_direction = SG_DXFER_TO_DEV;
                              break;
                        case CGC_DATA_READ:
                              hdr.dxfer_direction = SG_DXFER_FROM_DEV;
                              break;
                        case CGC_DATA_NONE:
                              hdr.dxfer_direction = SG_DXFER_NONE;
                              break;
                        default:
                              err = -EINVAL;
                  }
                  if (err)
                        break;

                  hdr.dxferp = cgc.buffer;
                  hdr.sbp = cgc.sense;
                  if (hdr.sbp)
                        hdr.mx_sb_len = sizeof(struct request_sense);
                  hdr.timeout = cgc.timeout;
                  hdr.cmdp = ((struct cdrom_generic_command __user*) arg)->cmd;
                  hdr.cmd_len = sizeof(cgc.cmd);

                  err = sg_io(file, q, bd_disk, &hdr);
                  if (err == -EFAULT)
                        break;

                  if (hdr.status)
                        err = -EIO;

                  cgc.stat = err;
                  cgc.buflen = hdr.resid;
                  if (copy_to_user(arg, &cgc, sizeof(cgc)))
                        err = -EFAULT;

                  break;
            }

            /*
             * old junk scsi send command ioctl
             */
            case SCSI_IOCTL_SEND_COMMAND:
                  printk(KERN_WARNING "program %s is using a deprecated SCSI ioctl, please convert it to SG_IO\n", current->comm);
                  err = -EINVAL;
                  if (!arg)
                        break;

                  err = sg_scsi_ioctl(file, q, bd_disk, arg);
                  break;
            case CDROMCLOSETRAY:
                  err = blk_send_start_stop(q, bd_disk, 0x03);
                  break;
            case CDROMEJECT:
                  err = blk_send_start_stop(q, bd_disk, 0x02);
                  break;
            default:
                  err = -ENOTTY;
      }

      blk_put_queue(q);
      return err;
}

EXPORT_SYMBOL(scsi_cmd_ioctl);

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