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 (driver_byte(result) == DRIVER_SENSE &&
 105            scsi_sense_valid(&sshdr)) {
 106                switch (sshdr.sense_key) {
 107                case ILLEGAL_REQUEST:
 108                        if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
 109                                sdev->lockable = 0;
 110                        else
 111                                sdev_printk(KERN_INFO, sdev,
 112                                            "ioctl_internal_command: "
 113                                            "ILLEGAL REQUEST "
 114                                            "asc=0x%x ascq=0x%x\n",
 115                                            sshdr.asc, sshdr.ascq);
 116                        break;
 117                case NOT_READY: /* This happens if there is no disc in drive */
 118                        if (sdev->removable)
 119                                break;
 120                        /* FALLTHROUGH */
 121                case UNIT_ATTENTION:
 122                        if (sdev->removable) {
 123                                sdev->changed = 1;
 124                                result = 0;     /* This is no longer considered an error */
 125                                break;
 126                        }
 127                        /* FALLTHROUGH -- for non-removable media */
 128                default:
 129                        sdev_printk(KERN_INFO, sdev,
 130                                    "ioctl_internal_command return code = %x\n",
 131                                    result);
 132                        scsi_print_sense_hdr(sdev, NULL, &sshdr);
 133                        break;
 134                }
 135        }
 136
 137        SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
 138                                      "IOCTL Releasing command\n"));
 139        return result;
 140}
 141
 142int scsi_set_medium_removal(struct scsi_device *sdev, char state)
 143{
 144        char scsi_cmd[MAX_COMMAND_SIZE];
 145        int ret;
 146
 147        if (!sdev->removable || !sdev->lockable)
 148               return 0;
 149
 150        scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
 151        scsi_cmd[1] = 0;
 152        scsi_cmd[2] = 0;
 153        scsi_cmd[3] = 0;
 154        scsi_cmd[4] = state;
 155        scsi_cmd[5] = 0;
 156
 157        ret = ioctl_internal_command(sdev, scsi_cmd,
 158                        IOCTL_NORMAL_TIMEOUT, NORMAL_RETRIES);
 159        if (ret == 0)
 160                sdev->locked = (state == SCSI_REMOVAL_PREVENT);
 161        return ret;
 162}
 163EXPORT_SYMBOL(scsi_set_medium_removal);
 164
 165/*
 166 * The scsi_ioctl_get_pci() function places into arg the value
 167 * pci_dev::slot_name (8 characters) for the PCI device (if any).
 168 * Returns: 0 on success
 169 *          -ENXIO if there isn't a PCI device pointer
 170 *                 (could be because the SCSI driver hasn't been
 171 *                  updated yet, or because it isn't a SCSI
 172 *                  device)
 173 *          any copy_to_user() error on failure there
 174 */
 175static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
 176{
 177        struct device *dev = scsi_get_device(sdev->host);
 178        const char *name;
 179
 180        if (!dev)
 181                return -ENXIO;
 182
 183        name = dev_name(dev);
 184
 185        /* compatibility with old ioctl which only returned
 186         * 20 characters */
 187        return copy_to_user(arg, name, min(strlen(name), (size_t)20))
 188                ? -EFAULT: 0;
 189}
 190
 191
 192/**
 193 * scsi_ioctl - Dispatch ioctl to scsi device
 194 * @sdev: scsi device receiving ioctl
 195 * @cmd: which ioctl is it
 196 * @arg: data associated with ioctl
 197 *
 198 * Description: The scsi_ioctl() function differs from most ioctls in that it
 199 * does not take a major/minor number as the dev field.  Rather, it takes
 200 * a pointer to a &struct scsi_device.
 201 */
 202int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 203{
 204        char scsi_cmd[MAX_COMMAND_SIZE];
 205        struct scsi_sense_hdr sense_hdr;
 206
 207        /* Check for deprecated ioctls ... all the ioctls which don't
 208         * follow the new unique numbering scheme are deprecated */
 209        switch (cmd) {
 210        case SCSI_IOCTL_SEND_COMMAND:
 211        case SCSI_IOCTL_TEST_UNIT_READY:
 212        case SCSI_IOCTL_BENCHMARK_COMMAND:
 213        case SCSI_IOCTL_SYNC:
 214        case SCSI_IOCTL_START_UNIT:
 215        case SCSI_IOCTL_STOP_UNIT:
 216                printk(KERN_WARNING "program %s is using a deprecated SCSI "
 217                       "ioctl, please convert it to SG_IO\n", current->comm);
 218                break;
 219        default:
 220                break;
 221        }
 222
 223        switch (cmd) {
 224        case SCSI_IOCTL_GET_IDLUN:
 225                if (!access_ok(arg, sizeof(struct scsi_idlun)))
 226                        return -EFAULT;
 227
 228                __put_user((sdev->id & 0xff)
 229                         + ((sdev->lun & 0xff) << 8)
 230                         + ((sdev->channel & 0xff) << 16)
 231                         + ((sdev->host->host_no & 0xff) << 24),
 232                         &((struct scsi_idlun __user *)arg)->dev_id);
 233                __put_user(sdev->host->unique_id,
 234                         &((struct scsi_idlun __user *)arg)->host_unique_id);
 235                return 0;
 236        case SCSI_IOCTL_GET_BUS_NUMBER:
 237                return put_user(sdev->host->host_no, (int __user *)arg);
 238        case SCSI_IOCTL_PROBE_HOST:
 239                return ioctl_probe(sdev->host, arg);
 240        case SCSI_IOCTL_SEND_COMMAND:
 241                if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
 242                        return -EACCES;
 243                return sg_scsi_ioctl(sdev->request_queue, NULL, 0, arg);
 244        case SCSI_IOCTL_DOORLOCK:
 245                return scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
 246        case SCSI_IOCTL_DOORUNLOCK:
 247                return scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
 248        case SCSI_IOCTL_TEST_UNIT_READY:
 249                return scsi_test_unit_ready(sdev, IOCTL_NORMAL_TIMEOUT,
 250                                            NORMAL_RETRIES, &sense_hdr);
 251        case SCSI_IOCTL_START_UNIT:
 252                scsi_cmd[0] = START_STOP;
 253                scsi_cmd[1] = 0;
 254                scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 255                scsi_cmd[4] = 1;
 256                return ioctl_internal_command(sdev, scsi_cmd,
 257                                     START_STOP_TIMEOUT, NORMAL_RETRIES);
 258        case SCSI_IOCTL_STOP_UNIT:
 259                scsi_cmd[0] = START_STOP;
 260                scsi_cmd[1] = 0;
 261                scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 262                scsi_cmd[4] = 0;
 263                return ioctl_internal_command(sdev, scsi_cmd,
 264                                     START_STOP_TIMEOUT, NORMAL_RETRIES);
 265        case SCSI_IOCTL_GET_PCI:
 266                return scsi_ioctl_get_pci(sdev, arg);
 267        case SG_SCSI_RESET:
 268                return scsi_ioctl_reset(sdev, arg);
 269        default:
 270                if (sdev->host->hostt->ioctl)
 271                        return sdev->host->hostt->ioctl(sdev, cmd, arg);
 272        }
 273        return -EINVAL;
 274}
 275EXPORT_SYMBOL(scsi_ioctl);
 276
 277/*
 278 * We can process a reset even when a device isn't fully operable.
 279 */
 280int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev, int cmd,
 281                bool ndelay)
 282{
 283        if (cmd == SG_SCSI_RESET && ndelay) {
 284                if (scsi_host_in_recovery(sdev->host))
 285                        return -EAGAIN;
 286        } else {
 287                if (!scsi_block_when_processing_errors(sdev))
 288                        return -ENODEV;
 289        }
 290
 291        return 0;
 292}
 293EXPORT_SYMBOL_GPL(scsi_ioctl_block_when_processing_errors);
 294