text: /*
   * Copyright (c) 2016-2019 Douglas Gilbert.
   * All rights reserved.
   * Use of this source code is governed by a BSD-style
   * license that can be found in the BSD_LICENSE file.
   *
   * SPDX-License-Identifier: BSD-2-Clause
   */
  
  #include <unistd.h>
  #include <fcntl.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <stdbool.h>
  #include <string.h>
  #include <ctype.h>
  #include <getopt.h>
  #define __STDC_FORMAT_MACROS 1
  #include <inttypes.h>
  
  #ifdef HAVE_CONFIG_H
  #include "config.h"
  #endif
  #include "sg_lib.h"
  #include "sg_lib_data.h"
  #include "sg_pt.h"
  #include "sg_cmds_basic.h"
  #include "sg_unaligned.h"
  #include "sg_pr2serr.h"
  
  /* A utility program originally written for the Linux OS SCSI subsystem.
   *
   *
   * This program issues the SCSI BACKGROUND CONTROL command to the given SCSI
   * device. Based on sbc4r10.pdf .
   */
  
  static const char * version_str = "1.10 20190113";
  
  #define BACKGROUND_CONTROL_SA 0x15
  
  #define SENSE_BUFF_LEN 64       /* Arbitrary, could be larger */
  #define DEF_PT_TIMEOUT  60      /* 60 seconds */
  
  static const char * cmd_name = "Background control";
  
  
  static struct option long_options[] = {
          {"ctl", required_argument, 0, 'c'},
          {"help", no_argument, 0, 'h'},
          {"time", required_argument, 0, 't'},
          {"verbose", no_argument, 0, 'v'},
          {"version", no_argument, 0, 'V'},
          {0, 0, 0, 0},
  };
  
  
  static void
  usage()
  {
      pr2serr("Usage: "
              "sg_bg_ctl  [--ctl=CTL] [--help] [--time=TN] [--verbose] "
              "[--version]\n"
              "                  DEVICE\n");
      pr2serr("  where:\n"
              "    --ctl=CTL|-c CTL    CTL is background operation control "
              "value\n"
              "                        default: 0 -> don't change background "
              "operations\n"
              "                        1 -> start; 2 -> stop\n"
              "    --help|-h          print out usage message\n"
              "    --time=TN|-t TN    TN (units 100 ms) is max time to perform "
              "background\n"
              "                       operations (def: 0 -> no limit)\n"
              "    --verbose|-v       increase verbosity\n"
              "    --version|-V       print version string and exit\n\n"
              "Performs a SCSI BACKGROUND CONTROL command. It can start or "
              "stop\n'advanced background operations'. Operations started by "
              "this command\n(i.e. when ctl=1) are termed as 'host initiated' "
              "and allow a resource or\nthin provisioned device (disk) to "
              "perform garbage collection type operations.\nThese may "
              "degrade performance while they occur. Hence it is best to\n"
              "perform this action while the computer is not too busy.\n");
  }
  
  /* Invokes a SCSI BACKGROUND CONTROL command (SBC-4).  Return of 0 -> success,
   * various SG_LIB_CAT_* positive values or -1 -> other errors */
  static int
  sg_ll_background_control(int sg_fd, unsigned int bo_ctl, unsigned int bo_time,
                           bool noisy, int verbose)
  {
      int k, ret, res, sense_cat;
      uint8_t bcCDB[16] = {SG_SERVICE_ACTION_IN_16,
             BACKGROUND_CONTROL_SA, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,
             0, 0, 0, 0};
      uint8_t sense_b[SENSE_BUFF_LEN];
      struct sg_pt_base * ptvp;
  
      if (bo_ctl)
          bcCDB[2] |= (bo_ctl & 0x3) << 6;
      if (bo_time)
          bcCDB[3] = bo_time;
      if (verbose) {
          pr2serr("    %s cdb: ", cmd_name);
          for (k = 0; k < (int)sizeof(bcCDB); ++k)
              pr2serr("%02x ", bcCDB[k]);
          pr2serr("\n");
      }
  
      ptvp = construct_scsi_pt_obj();
      if (NULL == ptvp) {
          pr2serr("%s: out of memory\n", cmd_name);
          return -1;
      }
      set_scsi_pt_cdb(ptvp, bcCDB, sizeof(bcCDB));
      set_scsi_pt_sense(ptvp, sense_b, sizeof(sense_b));
      res = do_scsi_pt(ptvp, sg_fd, DEF_PT_TIMEOUT, verbose);
      ret = sg_cmds_process_resp(ptvp, cmd_name, res, noisy, verbose,
                                 &sense_cat);
      if (-1 == ret)
          ret = sg_convert_errno(get_scsi_pt_os_err(ptvp));
      else if (-2 == ret) {
          switch (sense_cat) {
          case SG_LIB_CAT_RECOVERED:
          case SG_LIB_CAT_NO_SENSE:
              ret = 0;
              break;
          default:
              ret = sense_cat;
              break;
          }
      } else
          ret = 0;
      destruct_scsi_pt_obj(ptvp);
      return ret;
  }
  
  
  int
  main(int argc, char * argv[])
  {
      bool verbose_given = false;
      bool version_given = false;
      int sg_fd = -1;
      int res, c;
      unsigned int ctl = 0;
      unsigned int time_tnth = 0;
      int verbose = 0;
      const char * device_name = NULL;
      int ret = 0;
  
      while (1) {
          int option_index = 0;
  
          c = getopt_long(argc, argv, "c:ht:vV", long_options, &option_index);
          if (c == -1)
              break;
  
          switch (c) {
          case 'c':
              if ((1 != sscanf(optarg, "%4u", &ctl)) || (ctl > 3)) {
                  pr2serr("--ctl= expects a number from 0 to 3\n");
                  return SG_LIB_SYNTAX_ERROR;
              }
              break;
          case 'h':
          case '?':
              usage();
              return 0;
          case 't':
              if ((1 != sscanf(optarg, "%4u", &time_tnth)) ||
                  (time_tnth > 255)) {
                  pr2serr("--time= expects a number from 0 to 255\n");
                  return SG_LIB_SYNTAX_ERROR;
              }
              break;
          case 'v':
              verbose_given = true;
              ++verbose;
              break;
          case 'V':
              version_given = true;
              break;
          default:
              pr2serr("unrecognised option code 0x%x ??\n", c);
              usage();
              return SG_LIB_SYNTAX_ERROR;
          }
      }
      if (optind < argc) {
          if (NULL == device_name) {
              device_name = argv[optind];
              ++optind;
          }
          if (optind < argc) {
              for (; optind < argc; ++optind)
                  pr2serr("Unexpected extra argument: %s\n",
                          argv[optind]);
              usage();
              return SG_LIB_SYNTAX_ERROR;
          }
      }
  #ifdef DEBUG
      pr2serr("In DEBUG mode, ");
      if (verbose_given && version_given) {
          pr2serr("but override: '-vV' given, zero verbose and continue\n");
          verbose_given = false;
          version_given = false;
          verbose = 0;
      } else if (! verbose_given) {
          pr2serr("set '-vv'\n");
          verbose = 2;
      } else
          pr2serr("keep verbose=%d\n", verbose);
  #else
      if (verbose_given && version_given)
          pr2serr("Not in DEBUG mode, so '-vV' has no special action\n");
  #endif
      if (version_given) {
          pr2serr("version: %s\n", version_str);
          return 0;
      }
  
      if (NULL == device_name) {
          pr2serr("missing device name!\n\n");
          usage();
          return SG_LIB_SYNTAX_ERROR;
      }
  
      sg_fd = sg_cmds_open_device(device_name, false, verbose);
      if (sg_fd < 0) {
          if (verbose)
              pr2serr("open error: %s: %s\n", device_name,
                      safe_strerror(-sg_fd));
          ret = sg_convert_errno(-sg_fd);
          goto fini;
      }
  
      res = sg_ll_background_control(sg_fd, ctl, time_tnth, true, verbose);
      ret = res;
      if (res) {
          if (SG_LIB_CAT_INVALID_OP == res)
              pr2serr("%s command not supported\n", cmd_name);
          else {
              char b[80];
  
              sg_get_category_sense_str(res, sizeof(b), b, verbose);
              pr2serr("%s command: %s\n", cmd_name, b);
          }
      }
  
  fini:
      if (0 == verbose) {
          if (! sg_if_can2stderr("sg_bg_ctl failed: ", ret))
              pr2serr("Some error occurred, try again with '-v' or '-vv' for "
                      "more information\n");
      }
      if (sg_fd >= 0) {
          res = sg_cmds_close_device(sg_fd);
          if (res < 0) {
              pr2serr("close error: %s\n", safe_strerror(-res));
              if (0 == ret)
                  ret = sg_convert_errno(-res);
          }
      }
      return (ret >= 0) ? ret : SG_LIB_CAT_OTHER;
  }
  