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 #include <inttypes.h>
  22
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25
  26 #define VERSION "0.01"
  27
  28 int main(int argc, char* argv[])
  29 {
  30     char* input_path  = NULL;
  31     char* output_path = NULL;
  32     uint64_t bs = 512;
  33     uint32_t bs_modifier = 1;
  34     unsigned int count = 0;
  35     unsigned int r_in  = 0;
  36     unsigned int r_out = 0;
  37
  38     // flag parsing
  39     int arg = 0;
  40     for (arg = 1; arg < argc; arg++)
  41     {
  42         if (strstr(argv[arg], "if=")) {
  43             input_path  = strstr(argv[arg], "if=") + strlen("if=");
  44         } else if (strstr(argv[arg], "of=")) {
  45             output_path = strstr(argv[arg], "of=") + strlen("of=");
  46         } else if (strstr(argv[arg], "bs=")) {
  47             char* bs_value = strstr(argv[arg], "bs=") + strlen("bs=");
  48             char  bs_unit  = bs_value[strlen(bs_value) - 1];
  49             // if last character isn't a digit
  50             if (!isdigit(bs_unit)) {
  51                 switch(bs_unit)
  52                 {
  53                     case 'k':
  54                     case 'K':
  55                         bs_modifier = 1024;
  56                         break;
  57                     case 'm':
  58                     case 'M':
  59                         bs_modifier = 1024 * 1024;
  60                         break;
  61                     case 'g':
  62                     case 'G':
  63                         bs_modifier = 1024 * 1024 * 1024;
  64                         break;
  65                     default:
  66                         fprintf(stderr, "%s: invalid unit: '%c'\n",
  67                                          argv[0],           bs_unit);
  68                         return 1;
  69                 }
  70                 printf("%c\n", bs_unit);
  71                 // delete the unit, leaving just the number
  72                 bs_value[strlen(bs_value) - 1] = '\0';
  73             }
  74
  75             // validate input
  76             for (size_t i = 0; i < strlen(bs_value); i++)
  77             {
  78                 if (!isdigit(bs_value[i])) {
  79                     fprintf(stderr, "%s: invalid number: '%s'\n",
  80                                      argv[0],             bs_value);
  81                     return 1;
  82                 }
  83             }
  84
  85             bs = atoi(bs_value);
  86             if (bs == 0) {
  87                     fprintf(stderr, "%s: invalid number: '%"PRIu64"'\n",
  88                                      argv[0],             bs);
  89                     return 1;
  90                 }
  91
  92         } else if (strstr(argv[arg], "count=")) {
  93             char* count_value = strstr(argv[arg], "count=") + strlen("count=");
  94
  95             // validate input
  96             for (size_t i = 0; i < strlen(count_value); i++)
  97             {
  98                 if (!isdigit(count_value[i])) {
  99                     fprintf(stderr, "%s: invalid number: '%s'\n",
 100                                      argv[0],             count_value);
 101                     return 1;
 102                 }
 103             }
 104
 105             count = atoi(count_value);
 106             if (count == 0) {
 107                 fprintf(stderr, "0+0 records in\n"
 108                                 "0+0 records out\n"
 109                                 "0 bytes (0 B) copied\n");
 110                 return 0;
 111             }
 112         } else if (strcmp("--help", argv[arg]) == 0 || strcmp("-h", argv[arg]) == 0) {
 113             printf("Usage: %s\n", argv[0]);
 114             printf("[delim] must be a character and [field] starts at 1.\n"
 115                    "\n"
 116                    "    -h, --help              Print this message.\n"
 117                    "    -v, --version           Show version info.\n");
 118             return 0;
 119         } else if (strcmp("--version", argv[arg]) == 0 || strcmp("-v", argv[arg]) == 0) {
 120             printf("dd (mutos) v"VERSION"\n");
 121             return 0;
 122         } else {
 123             // no more flags left
 124             break;
 125         }
 126     }
 127
 128     FILE* input_file  = NULL;
 129     FILE* output_file = NULL;
 130
 131     int rc = 0;
 132
 133     if (!input_path || strcmp(input_path, "-") == 0) {
 134         input_file = stdin;
 135     } else {
 136         struct stat input_stat;
 137         rc = stat(input_path, &input_stat);
 138         if (rc < 0) {
 139             fprintf(stderr, "%s: %s: %s\n",
 140                              argv[0], strerror(errno), input_path);
 141             return 1;
 142         }
 143         input_file = fopen(input_path, "r");
 144     }
 145
 146     if (!input_file) {
 147         fprintf(stderr, "%s: %s: %s\n",
 148                          argv[0], strerror(errno), input_path);
 149         return 1;
 150     }
 151
 152     if (!output_path) {
 153         output_file = stdout;
 154     } else {
 155         struct stat output_stat;
 156         rc = stat(output_path, &output_stat);
 157         if (rc < 0 && errno != ENOENT) {
 158             fprintf(stderr, "%s: %s: %s\n",
 159                              argv[0], strerror(errno), input_path);
 160             return 1;
 161         }
 162         output_file = fopen(output_path, "w");
 163     }
 164
 165     if (!output_file) {
 166         fprintf(stderr, "%s: %s: %s\n",
 167                          argv[0], strerror(errno), output_path);
 168         return 1;
 169     }
 170
 171     int c = '\0';
 172     int bytes = 0;
 173
 174     c = fgetc(input_file);
 175     while (c != EOF)
 176     {
 177         bytes++;
 178         if (bytes % (bs*bs_modifier) == 0) {
 179             r_in++;
 180         }
 181         fputc(c, output_file);
 182         if (bytes % (bs*bs_modifier) == 0) {
 183             r_out++;
 184         }
 185         c = fgetc(input_file);
 186     }
 187
 188     fprintf(stderr, "%d+0 records in\n"
 189                     "%d+0 records out\n"
 190                     "%d bytes copied\n",
 191                      r_in, r_out, bytes);
 192     return 0;
 193 }