LXR linux/drivers/scsi/scsi

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Changes:
   4 * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 08/23/2000
   5 * - get rid of some verify_areas and use __copy*user and __get/put_user
   6 *   for the ones that remain
   7 */
   8#include <linux/module.h>
   9#include <linux/blkdev.h>
  10#include <linux/interrupt.h>
  11#include <linux/errno.h>
  12#include <linux/kernel.h>
  13#include <linux/sched.h>
  14#include <linux/mm.h>
  15#include <linux/string.h>
  16#include <linux/uaccess.h>
  17
  18#include <scsi/scsi.h>
  19#include <scsi/scsi_cmnd.h>
  20#include <scsi/scsi_device.h>
  21#include <scsi/scsi_eh.h>
  22#include <scsi/scsi_host.h>
  23#include <scsi/scsi_ioctl.h>
  24#include <scsi/sg.h>
  25#include <scsi/scsi_dbg.h>
  26
  27#include "scsi_logging.h"
  28
  29#define NORMAL_RETRIES                  5
  30#define IOCTL_NORMAL_TIMEOUT                    (10 * HZ)
  31
  32#define MAX_BUF PAGE_SIZE
  33
  34/**
  35 * ioctl_probe  --  return host identification
  36 * @host:       host to identify
  37 * @buffer:     userspace buffer for identification
  38 *
  39 * Return an identifying string at @buffer, if @buffer is non-NULL, filling
  40 * to the length stored at * (int *) @buffer.
  41 */
  42static int ioctl_probe(struct Scsi_Host *host, void __user *buffer)
  43{
  44        unsigned int len, slen;
  45        const char *string;
  46
  47        if (buffer) {
  48                if (get_user(len, (unsigned int __user *) buffer))
  49                        return -EFAULT;
  50
  51                if (host->hostt->info)
  52                        string = host->hostt->info(host);
  53                else
  54                        string = host->hostt->name;
  55                if (string) {
  56                        slen = strlen(string);
  57                        if (len > slen)
  58                                len = slen + 1;
  59                        if (copy_to_user(buffer, string, len))
  60                                return -EFAULT;
  61                }
  62        }
  63        return 1;
  64}
  65
  66/*
  67
  68 * The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
  69 * The IOCTL_NORMAL_TIMEOUT and NORMAL_RETRIES  variables are used.  
  70 * 
  71 * dev is the SCSI device struct ptr, *(int *) arg is the length of the
  72 * input data, if any, not including the command string & counts, 
  73 * *((int *)arg + 1) is the output buffer size in bytes.
  74 * 
  75 * *(char *) ((int *) arg)[2] the actual command byte.   
  76 * 
  77 * Note that if more than MAX_BUF bytes are requested to be transferred,
  78 * the ioctl will fail with error EINVAL.
  79 * 
  80 * This size *does not* include the initial lengths that were passed.
  81 * 
  82 * The SCSI command is read from the memory location immediately after the
  83 * length words, and the input data is right after the command.  The SCSI
  84 * routines know the command size based on the opcode decode.  
  85 * 
  86 * The output area is then filled in starting from the command byte. 
  87 */
  88
  89static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
  90                                  int timeout, int retries)
  91{
  92        int result;
  93        struct scsi_sense_hdr sshdr;
  94
  95        SCSI_LOG_IOCTL(1, sdev_printk(KERN_INFO, sdev,
  96                                      "Trying ioctl with scsi command %d\n", *cmd));
  97
  98        result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0,
  99                                  &sshdr, timeout, retries, NULL);
 100
 101        SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
 102                                      "Ioctl returned  0x%x\n", result));
 103
 104        if (result < 0)
 105                goto out;
 106        if (scsi_sense_valid(&sshdr)) {
 107                switch (sshdr.sense_key) {
 108                case ILLEGAL_REQUEST:
 109                        if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
 110                                sdev->lockable = 0;
 111                        else
 112                                sdev_printk(KERN_INFO, sdev,
 113                                            "ioctl_internal_command: "
 114                                            "ILLEGAL REQUEST "
 115                                            "asc=0x%x ascq=0x%x\n",
 116                                            sshdr.asc, sshdr.ascq);
 117                        break;
 118                case NOT_READY: /* This happens if there is no disc in drive */
 119                        if (sdev->removable)
 120                                break;
 121                        fallthrough;
 122                case UNIT_ATTENTION:
 123                        if (sdev->removable) {
 124                                sdev->changed = 1;
 125                                result = 0;     /* This is no longer considered an error */
 126                                break;
 127                        }
 128                        fallthrough;    /* for non-removable media */
 129                default:
 130                        sdev_printk(KERN_INFO, sdev,
 131                                    "ioctl_internal_command return code = %x\n",
 132                                    result);
 133                        scsi_print_sense_hdr(sdev, NULL, &sshdr);
 134                        break;
 135                }
 136        }
 137out:
 138        SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
 139                                      "IOCTL Releasing command\n"));
 140        return result;
 141}
 142
 143int scsi_set_medium_removal(struct scsi_device *sdev, char state)
 144{
 145        char scsi_cmd[MAX_COMMAND_SIZE];
 146        int ret;
 147
 148        if (!sdev->removable || !sdev->lockable)
 149               return 0;
 150
 151        scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
 152        scsi_cmd[1] = 0;
 153        scsi_cmd[2] = 0;
 154        scsi_cmd[3] = 0;
 155        scsi_cmd[4] = state;
 156        scsi_cmd[5] = 0;
 157
 158        ret = ioctl_internal_command(sdev, scsi_cmd,
 159                        IOCTL_NORMAL_TIMEOUT, NORMAL_RETRIES);
 160        if (ret == 0)
 161                sdev->locked = (state == SCSI_REMOVAL_PREVENT);
 162        return ret;
 163}
 164EXPORT_SYMBOL(scsi_set_medium_removal);
 165
 166/*
 167 * The scsi_ioctl_get_pci() function places into arg the value
 168 * pci_dev::slot_name (8 characters) for the PCI device (if any).
 169 * Returns: 0 on success
 170 *          -ENXIO if there isn't a PCI device pointer
 171 *                 (could be because the SCSI driver hasn't been
 172 *                  updated yet, or because it isn't a SCSI
 173 *                  device)
 174 *          any copy_to_user() error on failure there
 175 */
 176static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
 177{
 178        struct device *dev = scsi_get_device(sdev->host);
 179        const char *name;
 180
 181        if (!dev)
 182                return -ENXIO;
 183
 184        name = dev_name(dev);
 185
 186        /* compatibility with old ioctl which only returned
 187         * 20 characters */
 188        return copy_to_user(arg, name, min(strlen(name), (size_t)20))
 189                ? -EFAULT: 0;
 190}
 191
 192
 193static int scsi_ioctl_common(struct scsi_device *sdev, int cmd, void __user *arg)
 194{
 195        char scsi_cmd[MAX_COMMAND_SIZE];
 196        struct scsi_sense_hdr sense_hdr;
 197
 198        /* Check for deprecated ioctls ... all the ioctls which don't
 199         * follow the new unique numbering scheme are deprecated */
 200        switch (cmd) {
 201        case SCSI_IOCTL_SEND_COMMAND:
 202        case SCSI_IOCTL_TEST_UNIT_READY:
 203        case SCSI_IOCTL_BENCHMARK_COMMAND:
 204        case SCSI_IOCTL_SYNC:
 205        case SCSI_IOCTL_START_UNIT:
 206        case SCSI_IOCTL_STOP_UNIT:
 207                printk(KERN_WARNING "program %s is using a deprecated SCSI "
 208                       "ioctl, please convert it to SG_IO\n", current->comm);
 209                break;
 210        default:
 211                break;
 212        }
 213
 214        switch (cmd) {
 215        case SCSI_IOCTL_GET_IDLUN: {
 216                struct scsi_idlun v = {
 217                        .dev_id = (sdev->id & 0xff)
 218                                 + ((sdev->lun & 0xff) << 8)
 219                                 + ((sdev->channel & 0xff) << 16)
 220                                 + ((sdev->host->host_no & 0xff) << 24),
 221                        .host_unique_id = sdev->host->unique_id
 222                };
 223                if (copy_to_user(arg, &v, sizeof(struct scsi_idlun)))
 224                        return -EFAULT;
 225                return 0;
 226        }
 227        case SCSI_IOCTL_GET_BUS_NUMBER:
 228                return put_user(sdev->host->host_no, (int __user *)arg);
 229        case SCSI_IOCTL_PROBE_HOST:
 230                return ioctl_probe(sdev->host, arg);
 231        case SCSI_IOCTL_SEND_COMMAND:
 232                if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
 233                        return -EACCES;
 234                return sg_scsi_ioctl(sdev->request_queue, NULL, 0, arg);
 235        case SCSI_IOCTL_DOORLOCK:
 236                return scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
 237        case SCSI_IOCTL_DOORUNLOCK:
 238                return scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
 239        case SCSI_IOCTL_TEST_UNIT_READY:
 240                return scsi_test_unit_ready(sdev, IOCTL_NORMAL_TIMEOUT,
 241                                            NORMAL_RETRIES, &sense_hdr);
 242        case SCSI_IOCTL_START_UNIT:
 243                scsi_cmd[0] = START_STOP;
 244                scsi_cmd[1] = 0;
 245                scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 246                scsi_cmd[4] = 1;
 247                return ioctl_internal_command(sdev, scsi_cmd,
 248                                     START_STOP_TIMEOUT, NORMAL_RETRIES);
 249        case SCSI_IOCTL_STOP_UNIT:
 250                scsi_cmd[0] = START_STOP;
 251                scsi_cmd[1] = 0;
 252                scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 253                scsi_cmd[4] = 0;
 254                return ioctl_internal_command(sdev, scsi_cmd,
 255                                     START_STOP_TIMEOUT, NORMAL_RETRIES);
 256        case SCSI_IOCTL_GET_PCI:
 257                return scsi_ioctl_get_pci(sdev, arg);
 258        case SG_SCSI_RESET:
 259                return scsi_ioctl_reset(sdev, arg);
 260        }
 261        return -ENOIOCTLCMD;
 262}
 263
 264/**
 265 * scsi_ioctl - Dispatch ioctl to scsi device
 266 * @sdev: scsi device receiving ioctl
 267 * @cmd: which ioctl is it
 268 * @arg: data associated with ioctl
 269 *
 270 * Description: The scsi_ioctl() function differs from most ioctls in that it
 271 * does not take a major/minor number as the dev field.  Rather, it takes
 272 * a pointer to a &struct scsi_device.
 273 */
 274int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 275{
 276        int ret = scsi_ioctl_common(sdev, cmd, arg);
 277
 278        if (ret != -ENOIOCTLCMD)
 279                return ret;
 280
 281        if (sdev->host->hostt->ioctl)
 282                return sdev->host->hostt->ioctl(sdev, cmd, arg);
 283
 284        return -EINVAL;
 285}
 286EXPORT_SYMBOL(scsi_ioctl);
 287
 288#ifdef CONFIG_COMPAT
 289int scsi_compat_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 290{
 291        int ret = scsi_ioctl_common(sdev, cmd, arg);
 292
 293        if (ret != -ENOIOCTLCMD)
 294                return ret;
 295
 296        if (sdev->host->hostt->compat_ioctl)
 297                return sdev->host->hostt->compat_ioctl(sdev, cmd, arg);
 298
 299        return ret;
 300}
 301EXPORT_SYMBOL(scsi_compat_ioctl);
 302#endif
 303
 304/*
 305 * We can process a reset even when a device isn't fully operable.
 306 */
 307int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev, int cmd,
 308                bool ndelay)
 309{
 310        if (cmd == SG_SCSI_RESET && ndelay) {
 311                if (scsi_host_in_recovery(sdev->host))
 312                        return -EAGAIN;
 313        } else {
 314                if (!scsi_block_when_processing_errors(sdev))
 315                        return -ENODEV;
 316        }
 317
 318        return 0;
 319}
 320EXPORT_SYMBOL_GPL(scsi_ioctl_block_when_processing_errors);
 321