miscutils/mt.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   4  */
   5 //config:config MT
   6 //config:       bool "mt"
   7 //config:       default y
   8 //config:       help
   9 //config:         mt is used to control tape devices. You can use the mt utility
  10 //config:         to advance or rewind a tape past a specified number of archive
  11 //config:         files on the tape.
  12
  13 //usage:#define mt_trivial_usage
  14 //usage:       "[-f device] opcode value"
  15 //usage:#define mt_full_usage "\n\n"
  16 //usage:       "Control magnetic tape drive operation\n"
  17 //usage:       "\n"
  18 //usage:       "Available Opcodes:\n"
  19 //usage:       "\n"
  20 //usage:       "bsf bsfm bsr bss datacompression drvbuffer eof eom erase\n"
  21 //usage:       "fsf fsfm fsr fss load lock mkpart nop offline ras1 ras2\n"
  22 //usage:       "ras3 reset retension rewind rewoffline seek setblk setdensity\n"
  23 //usage:       "setpart tell unload unlock weof wset"
  24
  25 #include "libbb.h"
  26 #include <sys/mtio.h>
  27
  28 /* missing: eod/seod, stoptions, stwrthreshold, densities */
  29 static const short opcode_value[] = {
  30         MTBSF,
  31         MTBSFM,
  32         MTBSR,
  33         MTBSS,
  34         MTCOMPRESSION,
  35         MTEOM,
  36         MTERASE,
  37         MTFSF,
  38         MTFSFM,
  39         MTFSR,
  40         MTFSS,
  41         MTLOAD,
  42         MTLOCK,
  43         MTMKPART,
  44         MTNOP,
  45         MTOFFL,
  46         MTOFFL,
  47         MTRAS1,
  48         MTRAS2,
  49         MTRAS3,
  50         MTRESET,
  51         MTRETEN,
  52         MTREW,
  53         MTSEEK,
  54         MTSETBLK,
  55         MTSETDENSITY,
  56         MTSETDRVBUFFER,
  57         MTSETPART,
  58         MTTELL,
  59         MTWSM,
  60         MTUNLOAD,
  61         MTUNLOCK,
  62         MTWEOF,
  63         MTWEOF
  64 };
  65
  66 static const char opcode_name[] ALIGN1 =
  67         "bsf"             "\0"
  68         "bsfm"            "\0"
  69         "bsr"             "\0"
  70         "bss"             "\0"
  71         "datacompression" "\0"
  72         "eom"             "\0"
  73         "erase"           "\0"
  74         "fsf"             "\0"
  75         "fsfm"            "\0"
  76         "fsr"             "\0"
  77         "fss"             "\0"
  78         "load"            "\0"
  79         "lock"            "\0"
  80         "mkpart"          "\0"
  81         "nop"             "\0"
  82         "offline"         "\0"
  83         "rewoffline"      "\0"
  84         "ras1"            "\0"
  85         "ras2"            "\0"
  86         "ras3"            "\0"
  87         "reset"           "\0"
  88         "retension"       "\0"
  89         "rewind"          "\0"
  90         "seek"            "\0"
  91         "setblk"          "\0"
  92         "setdensity"      "\0"
  93         "drvbuffer"       "\0"
  94         "setpart"         "\0"
  95         "tell"            "\0"
  96         "wset"            "\0"
  97         "unload"          "\0"
  98         "unlock"          "\0"
  99         "eof"             "\0"
 100         "weof"            "\0";
 101
 102 int mt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 103 int mt_main(int argc UNUSED_PARAM, char **argv)
 104 {
 105         const char *file = "/dev/tape";
 106         struct mtop op;
 107         struct mtpos position;
 108         int fd, mode, idx;
 109
 110         if (!argv[1]) {
 111                 bb_show_usage();
 112         }
 113
 114         if (strcmp(argv[1], "-f") == 0) {
 115                 if (!argv[2] || !argv[3])
 116                         bb_show_usage();
 117                 file = argv[2];
 118                 argv += 2;
 119         }
 120
 121         idx = index_in_strings(opcode_name, argv[1]);
 122
 123         if (idx < 0)
 124                 bb_error_msg_and_die("unrecognized opcode %s", argv[1]);
 125
 126         op.mt_op = opcode_value[idx];
 127         if (argv[2])
 128                 op.mt_count = xatoi_positive(argv[2]);
 129         else
 130                 op.mt_count = 1;  /* One, not zero, right? */
 131
 132         switch (opcode_value[idx]) {
 133                 case MTWEOF:
 134                 case MTERASE:
 135                 case MTWSM:
 136                 case MTSETDRVBUFFER:
 137                         mode = O_WRONLY;
 138                         break;
 139
 140                 default:
 141                         mode = O_RDONLY;
 142                         break;
 143         }
 144
 145         fd = xopen(file, mode);
 146
 147         switch (opcode_value[idx]) {
 148                 case MTTELL:
 149                         ioctl_or_perror_and_die(fd, MTIOCPOS, &position, "%s", file);
 150                         printf("At block %d\n", (int) position.mt_blkno);
 151                         break;
 152
 153                 default:
 154                         ioctl_or_perror_and_die(fd, MTIOCTOP, &op, "%s", file);
 155                         break;
 156         }
 157
 158         return EXIT_SUCCESS;
 159 }