dd.c

   1 /*
   2     Copyright © 2013 Alastair Stuart
   3
   4     This program is open source software: you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation, either version 3 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12     GNU General Public License for more details.
  13 */
  14
  15 #include <stdio.h>
  16 #include <string.h>
  17 #include <stdint.h>
  18 #include <ctype.h>
  19 #include <stdlib.h>
  20 #include <errno.h>
  21
  22 #include <sys/types.h>
  23 #include <sys/stat.h>
  24
  25 #define VERSION "0.01"
  26
  27 int main(int argc, char* argv[])
  28 {
  29     char* input_path  = NULL;
  30     char* output_path = NULL;
  31     uint64_t bs = 512;
  32     uint32_t bs_modifier = 1;
  33     unsigned int count = 0;
  34     unsigned int r_in  = 0;
  35     unsigned int r_out = 0;
  36
  37     // flag parsing
  38     int arg = 0;
  39     for (arg = 1; arg < argc; arg++)
  40     {
  41         if (strstr(argv[arg], "if=")) {
  42             input_path  = strstr(argv[arg], "if=") + strlen("if=");
  43         } else if (strstr(argv[arg], "of=")) {
  44             output_path = strstr(argv[arg], "of=") + strlen("of=");
  45         } else if (strstr(argv[arg], "bs=")) {
  46             char* bs_value = strstr(argv[arg], "bs=") + strlen("bs=");
  47             char  bs_unit  = bs_value[strlen(bs_value) - 1];
  48             // if last character isn't a digit
  49             if (!isdigit(bs_unit)) {
  50                 switch(bs_unit)
  51                 {
  52                     case 'k':
  53                     case 'K':
  54                         bs_modifier = 1024;
  55                         break;
  56                     case 'm':
  57                     case 'M':
  58                         bs_modifier = 1024 * 1024;
  59                         break;
  60                     case 'g':
  61                     case 'G':
  62                         bs_modifier = 1024 * 1024 * 1024;
  63                         break;
  64                     default:
  65                         fprintf(stderr, "%s: invalid unit: '%c'\n",
  66                                          argv[0],           bs_unit);
  67                         return 1;
  68                 }
  69                 printf("%c\n", bs_unit);
  70                 // delete the unit, leaving just the number
  71                 bs_value[strlen(bs_value) - 1] = '\0';
  72             }
  73
  74             // validate input
  75             for (size_t i = 0; i < strlen(bs_value); i++)
  76             {
  77                 if (!isdigit(bs_value[i])) {
  78                     fprintf(stderr, "%s: invalid number: '%s'\n",
  79                                      argv[0],             bs_value);
  80                     return 1;
  81                 }
  82             }
  83
  84             bs = atoi(bs_value);
  85             if (bs == 0) {
  86                     fprintf(stderr, "%s: invalid number: '%zu'\n",
  87                                      argv[0],             bs);
  88                     return 1;
  89                 }
  90
  91         } else if (strstr(argv[arg], "count=")) {
  92             char* count_value = strstr(argv[arg], "count=") + strlen("count=");
  93
  94             // validate input
  95             for (size_t i = 0; i < strlen(count_value); i++)
  96             {
  97                 if (!isdigit(count_value[i])) {
  98                     fprintf(stderr, "%s: invalid number: '%s'\n",
  99                                      argv[0],             count_value);
 100                     return 1;
 101                 }
 102             }
 103
 104             count = atoi(count_value);
 105             if (count == 0) {
 106                 fprintf(stderr, "0+0 records in\n"
 107                                 "0+0 records out\n"
 108                                 "0 bytes (0 B) copied\n");
 109                 return 0;
 110             }
 111         } else if (strcmp("--help", argv[arg]) == 0 || strcmp("-h", argv[arg]) == 0) {
 112             printf("Usage: %s\n", argv[0]);
 113             printf("[delim] must be a character and [field] starts at 1.\n"
 114                    "\n"
 115                    "    -h, --help              Print this message.\n"
 116                    "    -v, --version           Show version info.\n");
 117             return 0;
 118         } else if (strcmp("--version", argv[arg]) == 0 || strcmp("-v", argv[arg]) == 0) {
 119             printf("dd (mutos) v"VERSION"\n");
 120             return 0;
 121         } else {
 122             // no more flags left
 123             break;
 124         }
 125     }
 126
 127     FILE* input_file  = NULL;
 128     FILE* output_file = NULL;
 129
 130     int rc = 0;
 131
 132     if (!input_path || strcmp(input_path, "-") == 0) {
 133         input_file = stdin;
 134     } else {
 135         struct stat input_stat;
 136         rc = stat(input_path, &input_stat);
 137         if (rc < 0) {
 138             fprintf(stderr, "%s: %s: %s\n",
 139                              argv[0], strerror(errno), input_path);
 140             return 1;
 141         }
 142         input_file = fopen(input_path, "r");
 143     }
 144
 145     if (!input_file) {
 146         fprintf(stderr, "%s: %s: %s\n",
 147                          argv[0], strerror(errno), input_path);
 148         return 1;
 149     }
 150
 151     if (!output_path) {
 152         output_file = stdout;
 153     } else {
 154         struct stat output_stat;
 155         rc = stat(output_path, &output_stat);
 156         if (rc < 0 && errno != ENOENT) {
 157             fprintf(stderr, "%s: %s: %s\n",
 158                              argv[0], strerror(errno), input_path);
 159             return 1;
 160         }
 161         output_file = fopen(output_path, "w");
 162     }
 163
 164     if (!output_file) {
 165         fprintf(stderr, "%s: %s: %s\n",
 166                          argv[0], strerror(errno), output_path);
 167         return 1;
 168     }
 169
 170     int c = '\0';
 171     int bytes = 0;
 172
 173     c = fgetc(input_file);
 174     while (c != EOF)
 175     {
 176         bytes++;
 177         if (bytes % (bs*bs_modifier) == 0) {
 178             r_in++;
 179         }
 180         fputc(c, output_file);
 181         if (bytes % (bs*bs_modifier) == 0) {
 182             r_out++;
 183         }
 184         c = fgetc(input_file);
 185     }
 186
 187     fprintf(stderr, "%d+0 records in\n"
 188                     "%d+0 records out\n"
 189                     "%d bytes copied\n",
 190                      r_in, r_out, bytes);
 191     return 0;
 192 }