dd.c

   1 /*
   2  * Copyright (c) 1999 by David I. Bell
   3  * Permission is granted to use, distribute, or modify this source,
   4  * provided that this copyright notice remains intact.
   5  *
   6  * The "dd" command, originally taken from sash.
   7  *
   8  * Permission to distribute this code under the GPL has been granted.
   9  * Majorly modified, and bugs fixed for busybox by Erik Andersen <andersee@debian.org> <andersen@lineo.com>
  10  */
  11
  12 #include "internal.h"
  13 #ifdef BB_DD
  14
  15 const char dd_usage[] =
  16 "Copy a file, converting and formatting according to options\n\
  17 \n\
  18 usage: [if=name] [of=name] [bs=n] [count=n]\n\
  19 \tif=FILE\tread from FILE instead of stdin\n\
  20 \tof=FILE\twrite to FILE instead of stout\n\
  21 \tbs=n\tread and write N bytes at a time\n\
  22 \tcount=n\tcopy only n input blocks\n\
  23 \n\
  24 BYTES may be suffixed: by k for x1024, b for x512, and w for x2.\n";
  25
  26
  27 #include <stdio.h>
  28 #include <dirent.h>
  29 #include <errno.h>
  30 #include <fcntl.h>
  31 #include <signal.h>
  32 #include <time.h>
  33
  34
  35 #define PAR_NONE        0
  36 #define PAR_IF          1
  37 #define PAR_OF          2
  38 #define PAR_BS          3
  39 #define PAR_COUNT       4
  40
  41
  42 typedef struct
  43 {
  44         const char *    name;
  45         int             value;
  46 } PARAM;
  47
  48
  49 static const PARAM      params[] =
  50 {
  51         {"if",          PAR_IF},
  52         {"of",          PAR_OF},
  53         {"bs",          PAR_BS},
  54         {"count",       PAR_COUNT},
  55         {NULL,          PAR_NONE}
  56 };
  57
  58
  59 static  long    getNum(const char * cp);
  60
  61 extern int
  62 dd_main (struct FileInfo *unused, int argc, char **argv)
  63 {
  64         const char *    str;
  65         const PARAM *   par;
  66         const char *    inFile;
  67         const char *    outFile;
  68         char *          cp;
  69         int             inFd;
  70         int             outFd;
  71         int             inCc=0;
  72         int             outCc;
  73         int             blockSize;
  74         long            count;
  75         long            intotal;
  76         long            outTotal;
  77         unsigned char*  buf;
  78         unsigned char   localBuf[BUF_SIZE];
  79
  80         inFile = NULL;
  81         outFile = NULL;
  82         blockSize = 512;
  83         count = 1;
  84
  85
  86         while (--argc > 0)
  87         {
  88                 str = *++argv;
  89                 cp = strchr(str, '=');
  90
  91                 if (cp == NULL)
  92                 {
  93                         fprintf(stderr, "Bad dd argument\n");
  94                         goto usage;
  95                 }
  96
  97                 *cp++ = '\0';
  98
  99                 for (par = params; par->name; par++)
 100                 {
 101                         if (strcmp(str, par->name) == 0)
 102                                 break;
 103                 }
 104
 105                 switch (par->value)
 106                 {
 107                         case PAR_IF:
 108                                 if (inFile)
 109                                 {
 110                                         fprintf(stderr, "Multiple input files illegal\n");
 111                                         goto usage;
 112                                 }
 113
 114                                 //fprintf(stderr, "if=%s\n", cp);
 115                                 inFile = cp;
 116                                 break;
 117
 118                         case PAR_OF:
 119                                 if (outFile)
 120                                 {
 121                                         fprintf(stderr, "Multiple output files illegal\n");
 122                                         goto usage;
 123                                 }
 124
 125                                 //fprintf(stderr, "of=%s\n", cp);
 126                                 outFile = cp;
 127                                 break;
 128
 129                         case PAR_BS:
 130                                 blockSize = getNum(cp);
 131                                 //fprintf(stderr, "bs=%d\n", blockSize);
 132
 133                                 if (blockSize <= 0)
 134                                 {
 135                                         fprintf(stderr, "Bad block size value\n");
 136                                         goto usage;
 137                                 }
 138
 139                                 break;
 140
 141                         case PAR_COUNT:
 142                                 count = getNum(cp);
 143                                 //fprintf(stderr, "count=%ld\n", count);
 144
 145                                 if (count < 0)
 146                                 {
 147                                         fprintf(stderr, "Bad count value\n");
 148                                         goto usage;
 149                                 }
 150
 151                                 break;
 152
 153                         default:
 154                                 goto usage;
 155                 }
 156         }
 157
 158         buf = localBuf;
 159
 160         if (blockSize > sizeof(localBuf))
 161         {
 162                 buf = malloc(blockSize);
 163
 164                 if (buf == NULL)
 165                 {
 166                         fprintf(stderr, "Cannot allocate buffer\n");
 167                         return 1;
 168                 }
 169         }
 170
 171         intotal = 0;
 172         outTotal = 0;
 173
 174         if (inFile == NULL)
 175             inFd = STDIN;
 176         else
 177             inFd = open(inFile, 0);
 178
 179         if (inFd < 0)
 180         {
 181                 perror(inFile);
 182
 183                 if (buf != localBuf)
 184                         free(buf);
 185
 186                 return 1;
 187         }
 188
 189         if (outFile == NULL)
 190             outFd = STDOUT;
 191         else
 192             outFd = creat(outFile, 0666);
 193
 194         if (outFd < 0)
 195         {
 196                 perror(outFile);
 197                 close(inFd);
 198
 199                 if (buf != localBuf)
 200                         free(buf);
 201
 202                 return 1;
 203         }
 204
 205         while ( outTotal < count*blockSize )
 206         {
 207                 inCc = read(inFd, buf, blockSize);
 208                 if (inCc < 0) {
 209                     perror(inFile);
 210                     goto cleanup;
 211                 }
 212                 //fprintf(stderr, "read in =%d\n", inCc);
 213                 intotal += inCc;
 214                 cp = buf;
 215
 216
 217                 while ( intotal > outTotal )
 218                 {
 219                         if (outTotal+inCc > count*blockSize)
 220                             inCc=count*blockSize-outTotal;
 221                         outCc = write(outFd, cp, inCc);
 222                         if (outCc < 0)
 223                         {
 224                                 perror(outFile);
 225                                 goto cleanup;
 226                         }
 227                         //fprintf(stderr, "wrote out =%d\n", outCc);
 228
 229                         inCc -= outCc;
 230                         cp += outCc;
 231                         outTotal += outCc;
 232                         //fprintf(stderr, "outTotal=%ld\n", outTotal);
 233                 }
 234         }
 235
 236         if (inCc < 0)
 237                 perror(inFile);
 238
 239 cleanup:
 240         close(inFd);
 241
 242         if (close(outFd) < 0)
 243                 perror(outFile);
 244
 245         if (buf != localBuf)
 246                 free(buf);
 247
 248         printf("%ld+%d records in\n", intotal / blockSize,
 249                 (intotal % blockSize) != 0);
 250
 251         printf("%ld+%d records out\n", outTotal / blockSize,
 252                 (outTotal % blockSize) != 0);
 253         return 0;
 254 usage:
 255
 256         fprintf(stderr, "%s", dd_usage);
 257         return 1;
 258 }
 259
 260
 261 /*
 262  * Read a number with a possible multiplier.
 263  * Returns -1 if the number format is illegal.
 264  */
 265 static long
 266 getNum(const char * cp)
 267 {
 268         long    value;
 269
 270         if (!isDecimal(*cp))
 271                 return -1;
 272
 273         value = 0;
 274
 275         while (isDecimal(*cp))
 276                 value = value * 10 + *cp++ - '0';
 277
 278         switch (*cp++)
 279         {
 280                 case 'k':
 281                         value *= 1024;
 282                         break;
 283
 284                 case 'b':
 285                         value *= 512;
 286                         break;
 287
 288                 case 'w':
 289                         value *= 2;
 290                         break;
 291
 292                 case '\0':
 293                         return value;
 294
 295                 default:
 296                         return -1;
 297         }
 298
 299         if (*cp)
 300                 return -1;
 301
 302         return value;
 303 }
 304
 305 #endif
 306 /* END CODE */
 307