drivers/scsi/scsi_ioctl.c

   1 /*
   2  * Changes:
   3  * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 08/23/2000
   4  * - get rid of some verify_areas and use __copy*user and __get/put_user
   5  *   for the ones that remain
   6  */
   7 #include <linux/module.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/errno.h>
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/string.h>
  15 #include <linux/uaccess.h>
  16
  17 #include <scsi/scsi.h>
  18 #include <scsi/scsi_cmnd.h>
  19 #include <scsi/scsi_device.h>
  20 #include <scsi/scsi_eh.h>
  21 #include <scsi/scsi_host.h>
  22 #include <scsi/scsi_ioctl.h>
  23 #include <scsi/sg.h>
  24 #include <scsi/scsi_dbg.h>
  25
  26 #include "scsi_logging.h"
  27
  28 #define NORMAL_RETRIES                  5
  29 #define IOCTL_NORMAL_TIMEOUT                    (10 * HZ)
  30
  31 #define MAX_BUF PAGE_SIZE
  32
  33 /**
  34  * ioctl_probe  --  return host identification
  35  * @host:       host to identify
  36  * @buffer:     userspace buffer for identification
  37  *
  38  * Return an identifying string at @buffer, if @buffer is non-NULL, filling
  39  * to the length stored at * (int *) @buffer.
  40  */
  41 static int ioctl_probe(struct Scsi_Host *host, void __user *buffer)
  42 {
  43         unsigned int len, slen;
  44         const char *string;
  45
  46         if (buffer) {
  47                 if (get_user(len, (unsigned int __user *) buffer))
  48                         return -EFAULT;
  49
  50                 if (host->hostt->info)
  51                         string = host->hostt->info(host);
  52                 else
  53                         string = host->hostt->name;
  54                 if (string) {
  55                         slen = strlen(string);
  56                         if (len > slen)
  57                                 len = slen + 1;
  58                         if (copy_to_user(buffer, string, len))
  59                                 return -EFAULT;
  60                 }
  61         }
  62         return 1;
  63 }
  64
  65 /*
  66
  67  * The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
  68  * The IOCTL_NORMAL_TIMEOUT and NORMAL_RETRIES  variables are used.
  69  *
  70  * dev is the SCSI device struct ptr, *(int *) arg is the length of the
  71  * input data, if any, not including the command string & counts,
  72  * *((int *)arg + 1) is the output buffer size in bytes.
  73  *
  74  * *(char *) ((int *) arg)[2] the actual command byte.
  75  *
  76  * Note that if more than MAX_BUF bytes are requested to be transferred,
  77  * the ioctl will fail with error EINVAL.
  78  *
  79  * This size *does not* include the initial lengths that were passed.
  80  *
  81  * The SCSI command is read from the memory location immediately after the
  82  * length words, and the input data is right after the command.  The SCSI
  83  * routines know the command size based on the opcode decode.
  84  *
  85  * The output area is then filled in starting from the command byte.
  86  */
  87
  88 static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
  89                                   int timeout, int retries)
  90 {
  91         int result;
  92         struct scsi_sense_hdr sshdr;
  93
  94         SCSI_LOG_IOCTL(1, sdev_printk(KERN_INFO, sdev,
  95                                       "Trying ioctl with scsi command %d\n", *cmd));
  96
  97         result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0,
  98                                   &sshdr, timeout, retries, NULL);
  99
 100         SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
 101                                       "Ioctl returned  0x%x\n", result));
 102
 103         if ((driver_byte(result) & DRIVER_SENSE) &&
 104             (scsi_sense_valid(&sshdr))) {
 105                 switch (sshdr.sense_key) {
 106                 case ILLEGAL_REQUEST:
 107                         if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
 108                                 sdev->lockable = 0;
 109                         else
 110                                 sdev_printk(KERN_INFO, sdev,
 111                                             "ioctl_internal_command: "
 112                                             "ILLEGAL REQUEST "
 113                                             "asc=0x%x ascq=0x%x\n",
 114                                             sshdr.asc, sshdr.ascq);
 115                         break;
 116                 case NOT_READY: /* This happens if there is no disc in drive */
 117                         if (sdev->removable)
 118                                 break;
 119                         /* FALLTHROUGH */
 120                 case UNIT_ATTENTION:
 121                         if (sdev->removable) {
 122                                 sdev->changed = 1;
 123                                 result = 0;     /* This is no longer considered an error */
 124                                 break;
 125                         }
 126                         /* FALLTHROUGH -- for non-removable media */
 127                 default:
 128                         sdev_printk(KERN_INFO, sdev,
 129                                     "ioctl_internal_command return code = %x\n",
 130                                     result);
 131                         scsi_print_sense_hdr(sdev, NULL, &sshdr);
 132                         break;
 133                 }
 134         }
 135
 136         SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
 137                                       "IOCTL Releasing command\n"));
 138         return result;
 139 }
 140
 141 int scsi_set_medium_removal(struct scsi_device *sdev, char state)
 142 {
 143         char scsi_cmd[MAX_COMMAND_SIZE];
 144         int ret;
 145
 146         if (!sdev->removable || !sdev->lockable)
 147                return 0;
 148
 149         scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
 150         scsi_cmd[1] = 0;
 151         scsi_cmd[2] = 0;
 152         scsi_cmd[3] = 0;
 153         scsi_cmd[4] = state;
 154         scsi_cmd[5] = 0;
 155
 156         ret = ioctl_internal_command(sdev, scsi_cmd,
 157                         IOCTL_NORMAL_TIMEOUT, NORMAL_RETRIES);
 158         if (ret == 0)
 159                 sdev->locked = (state == SCSI_REMOVAL_PREVENT);
 160         return ret;
 161 }
 162 EXPORT_SYMBOL(scsi_set_medium_removal);
 163
 164 /*
 165  * The scsi_ioctl_get_pci() function places into arg the value
 166  * pci_dev::slot_name (8 characters) for the PCI device (if any).
 167  * Returns: 0 on success
 168  *          -ENXIO if there isn't a PCI device pointer
 169  *                 (could be because the SCSI driver hasn't been
 170  *                  updated yet, or because it isn't a SCSI
 171  *                  device)
 172  *          any copy_to_user() error on failure there
 173  */
 174 static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
 175 {
 176         struct device *dev = scsi_get_device(sdev->host);
 177         const char *name;
 178
 179         if (!dev)
 180                 return -ENXIO;
 181
 182         name = dev_name(dev);
 183
 184         /* compatibility with old ioctl which only returned
 185          * 20 characters */
 186         return copy_to_user(arg, name, min(strlen(name), (size_t)20))
 187                 ? -EFAULT: 0;
 188 }
 189
 190
 191 /**
 192  * scsi_ioctl - Dispatch ioctl to scsi device
 193  * @sdev: scsi device receiving ioctl
 194  * @cmd: which ioctl is it
 195  * @arg: data associated with ioctl
 196  *
 197  * Description: The scsi_ioctl() function differs from most ioctls in that it
 198  * does not take a major/minor number as the dev field.  Rather, it takes
 199  * a pointer to a &struct scsi_device.
 200  */
 201 int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 202 {
 203         char scsi_cmd[MAX_COMMAND_SIZE];
 204         struct scsi_sense_hdr sense_hdr;
 205
 206         /* Check for deprecated ioctls ... all the ioctls which don't
 207          * follow the new unique numbering scheme are deprecated */
 208         switch (cmd) {
 209         case SCSI_IOCTL_SEND_COMMAND:
 210         case SCSI_IOCTL_TEST_UNIT_READY:
 211         case SCSI_IOCTL_BENCHMARK_COMMAND:
 212         case SCSI_IOCTL_SYNC:
 213         case SCSI_IOCTL_START_UNIT:
 214         case SCSI_IOCTL_STOP_UNIT:
 215                 printk(KERN_WARNING "program %s is using a deprecated SCSI "
 216                        "ioctl, please convert it to SG_IO\n", current->comm);
 217                 break;
 218         default:
 219                 break;
 220         }
 221
 222         switch (cmd) {
 223         case SCSI_IOCTL_GET_IDLUN:
 224                 if (!access_ok(VERIFY_WRITE, arg, sizeof(struct scsi_idlun)))
 225                         return -EFAULT;
 226
 227                 __put_user((sdev->id & 0xff)
 228                          + ((sdev->lun & 0xff) << 8)
 229                          + ((sdev->channel & 0xff) << 16)
 230                          + ((sdev->host->host_no & 0xff) << 24),
 231                          &((struct scsi_idlun __user *)arg)->dev_id);
 232                 __put_user(sdev->host->unique_id,
 233                          &((struct scsi_idlun __user *)arg)->host_unique_id);
 234                 return 0;
 235         case SCSI_IOCTL_GET_BUS_NUMBER:
 236                 return put_user(sdev->host->host_no, (int __user *)arg);
 237         case SCSI_IOCTL_PROBE_HOST:
 238                 return ioctl_probe(sdev->host, arg);
 239         case SCSI_IOCTL_SEND_COMMAND:
 240                 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
 241                         return -EACCES;
 242                 return sg_scsi_ioctl(sdev->request_queue, NULL, 0, arg);
 243         case SCSI_IOCTL_DOORLOCK:
 244                 return scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
 245         case SCSI_IOCTL_DOORUNLOCK:
 246                 return scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
 247         case SCSI_IOCTL_TEST_UNIT_READY:
 248                 return scsi_test_unit_ready(sdev, IOCTL_NORMAL_TIMEOUT,
 249                                             NORMAL_RETRIES, &sense_hdr);
 250         case SCSI_IOCTL_START_UNIT:
 251                 scsi_cmd[0] = START_STOP;
 252                 scsi_cmd[1] = 0;
 253                 scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 254                 scsi_cmd[4] = 1;
 255                 return ioctl_internal_command(sdev, scsi_cmd,
 256                                      START_STOP_TIMEOUT, NORMAL_RETRIES);
 257         case SCSI_IOCTL_STOP_UNIT:
 258                 scsi_cmd[0] = START_STOP;
 259                 scsi_cmd[1] = 0;
 260                 scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 261                 scsi_cmd[4] = 0;
 262                 return ioctl_internal_command(sdev, scsi_cmd,
 263                                      START_STOP_TIMEOUT, NORMAL_RETRIES);
 264         case SCSI_IOCTL_GET_PCI:
 265                 return scsi_ioctl_get_pci(sdev, arg);
 266         case SG_SCSI_RESET:
 267                 return scsi_ioctl_reset(sdev, arg);
 268         default:
 269                 if (sdev->host->hostt->ioctl)
 270                         return sdev->host->hostt->ioctl(sdev, cmd, arg);
 271         }
 272         return -EINVAL;
 273 }
 274 EXPORT_SYMBOL(scsi_ioctl);
 275
 276 /*
 277  * We can process a reset even when a device isn't fully operable.
 278  */
 279 int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev, int cmd,
 280                 bool ndelay)
 281 {
 282         if (cmd == SG_SCSI_RESET && ndelay) {
 283                 if (scsi_host_in_recovery(sdev->host))
 284                         return -EAGAIN;
 285         } else {
 286                 if (!scsi_block_when_processing_errors(sdev))
 287                         return -ENODEV;
 288         }
 289
 290         return 0;
 291 }
 292 EXPORT_SYMBOL_GPL(scsi_ioctl_block_when_processing_errors);