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 (2.7 kb)"
   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 //applet:IF_MT(APPLET(mt, BB_DIR_BIN, BB_SUID_DROP))
  14
  15 //kbuild:lib-$(CONFIG_MT) += mt.o
  16
  17 //usage:#define mt_trivial_usage
  18 //usage:       "[-f DEVICE] OPCODE VALUE"
  19 //usage:#define mt_full_usage "\n\n"
  20 //usage:       "Control magnetic tape drive operation\n"
  21 //usage:       "\n"
  22 //usage:       "Opcodes:\n"
  23 //usage:       "\n"
  24 //usage:       "bsf bsfm bsr bss datacompression drvbuffer eof eom erase\n"
  25 //usage:       "fsf fsfm fsr fss load lock mkpart nop offline ras1 ras2\n"
  26 //usage:       "ras3 reset retension rewind rewoffline seek setblk setdensity\n"
  27 //usage:       "setpart tell unload unlock weof wset"
  28
  29 #include "libbb.h"
  30 #include <sys/mtio.h>
  31
  32 /* missing: eod/seod, stoptions, stwrthreshold, densities */
  33 static const short opcode_value[] ALIGN2 = {
  34         MTBSF,
  35         MTBSFM,
  36         MTBSR,
  37         MTBSS,
  38         MTCOMPRESSION,
  39         MTEOM,
  40         MTERASE,
  41         MTFSF,
  42         MTFSFM,
  43         MTFSR,
  44         MTFSS,
  45         MTLOAD,
  46         MTLOCK,
  47         MTMKPART,
  48         MTNOP,
  49         MTOFFL,
  50         MTOFFL,
  51         MTRAS1,
  52         MTRAS2,
  53         MTRAS3,
  54         MTRESET,
  55         MTRETEN,
  56         MTREW,
  57         MTSEEK,
  58         MTSETBLK,
  59         MTSETDENSITY,
  60         MTSETDRVBUFFER,
  61         MTSETPART,
  62         MTTELL,
  63         MTWSM,
  64         MTUNLOAD,
  65         MTUNLOCK,
  66         MTWEOF,
  67         MTWEOF
  68 };
  69
  70 static const char opcode_name[] ALIGN1 =
  71         "bsf"             "\0"
  72         "bsfm"            "\0"
  73         "bsr"             "\0"
  74         "bss"             "\0"
  75         "datacompression" "\0"
  76         "eom"             "\0"
  77         "erase"           "\0"
  78         "fsf"             "\0"
  79         "fsfm"            "\0"
  80         "fsr"             "\0"
  81         "fss"             "\0"
  82         "load"            "\0"
  83         "lock"            "\0"
  84         "mkpart"          "\0"
  85         "nop"             "\0"
  86         "offline"         "\0"
  87         "rewoffline"      "\0"
  88         "ras1"            "\0"
  89         "ras2"            "\0"
  90         "ras3"            "\0"
  91         "reset"           "\0"
  92         "retension"       "\0"
  93         "rewind"          "\0"
  94         "seek"            "\0"
  95         "setblk"          "\0"
  96         "setdensity"      "\0"
  97         "drvbuffer"       "\0"
  98         "setpart"         "\0"
  99         "tell"            "\0"
 100         "wset"            "\0"
 101         "unload"          "\0"
 102         "unlock"          "\0"
 103         "eof"             "\0"
 104         "weof"            "\0";
 105
 106 int mt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 107 int mt_main(int argc UNUSED_PARAM, char **argv)
 108 {
 109         const char *file = "/dev/tape";
 110         struct mtop op;
 111         struct mtpos position;
 112         int fd, mode, idx;
 113
 114         if (!argv[1]) {
 115                 bb_show_usage();
 116         }
 117
 118         if (strcmp(argv[1], "-f") == 0) {
 119                 if (!argv[2] || !argv[3])
 120                         bb_show_usage();
 121                 file = argv[2];
 122                 argv += 2;
 123         }
 124
 125         idx = index_in_strings(opcode_name, argv[1]);
 126
 127         if (idx < 0)
 128                 bb_error_msg_and_die("unrecognized opcode %s", argv[1]);
 129
 130         op.mt_op = opcode_value[idx];
 131         if (argv[2])
 132                 op.mt_count = xatoi_positive(argv[2]);
 133         else
 134                 op.mt_count = 1;  /* One, not zero, right? */
 135
 136         switch (opcode_value[idx]) {
 137                 case MTWEOF:
 138                 case MTERASE:
 139                 case MTWSM:
 140                 case MTSETDRVBUFFER:
 141                         mode = O_WRONLY;
 142                         break;
 143
 144                 default:
 145                         mode = O_RDONLY;
 146                         break;
 147         }
 148
 149         fd = xopen(file, mode);
 150
 151         switch (opcode_value[idx]) {
 152                 case MTTELL:
 153                         ioctl_or_perror_and_die(fd, MTIOCPOS, &position, "%s", file);
 154                         printf("At block %d\n", (int) position.mt_blkno);
 155                         break;
 156
 157                 default:
 158                         ioctl_or_perror_and_die(fd, MTIOCTOP, &op, "%s", file);
 159                         break;
 160         }
 161
 162         return EXIT_SUCCESS;
 163 }