dd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini dd implementation for busybox
   4  *
   5  *
   6  * Copyright (C) 2000 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  *
  22  */
  23
  24 #include <sys/types.h>
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <unistd.h>
  28 #include <string.h>
  29 #include <fcntl.h>
  30 #include "busybox.h"
  31
  32
  33 static const struct suffix_mult dd_suffixes[] = {
  34         { "c", 1 },
  35         { "w", 2 },
  36         { "b", 512 },
  37         { "kD", 1000 },
  38         { "k", 1024 },
  39         { "MD", 1000000 },
  40         { "M", 1048576 },
  41         { "GD", 1000000000 },
  42         { "G", 1073741824 },
  43         { NULL, 0 }
  44 };
  45
  46 int dd_main(int argc, char **argv)
  47 {
  48         int i, ifd, ofd, oflag, sync_flag = FALSE, trunc = TRUE;
  49         size_t in_full = 0, in_part = 0, out_full = 0, out_part = 0;
  50         size_t bs = 512, count = -1;
  51         ssize_t n;
  52         off_t seek = 0, skip = 0;
  53         FILE *statusfp;
  54         char *infile = NULL, *outfile = NULL, *buf;
  55
  56         for (i = 1; i < argc; i++) {
  57                 if (strncmp("bs=", argv[i], 3) == 0)
  58                         bs = parse_number(argv[i]+3, dd_suffixes);
  59                 else if (strncmp("count=", argv[i], 6) == 0)
  60                         count = parse_number(argv[i]+6, dd_suffixes);
  61                 else if (strncmp("seek=", argv[i], 5) == 0)
  62                         seek = parse_number(argv[i]+5, dd_suffixes);
  63                 else if (strncmp("skip=", argv[i], 5) == 0)
  64                         skip = parse_number(argv[i]+5, dd_suffixes);
  65                 else if (strncmp("if=", argv[i], 3) == 0)
  66                         infile = argv[i]+3;
  67                 else if (strncmp("of=", argv[i], 3) == 0)
  68                         outfile = argv[i]+3;
  69                 else if (strncmp("conv=", argv[i], 5) == 0) {
  70                         buf = argv[i]+5;
  71                         while (1) {
  72                                 if (strncmp("notrunc", buf, 7) == 0) {
  73                                         trunc = FALSE;
  74                                         buf += 7;
  75                                 } else if (strncmp("sync", buf, 4) == 0) {
  76                                         sync_flag = TRUE;
  77                                         buf += 4;
  78                                 } else {
  79                                         error_msg_and_die("invalid conversion `%s'", argv[i]+5);
  80                                 }
  81                                 if (buf[0] == '\0')
  82                                         break;
  83                                 if (buf[0] == ',')
  84                                         buf++;
  85                         }
  86                 } else
  87                         show_usage();
  88         }
  89
  90         buf = xmalloc(bs);
  91
  92         if (infile != NULL) {
  93                 if ((ifd = open(infile, O_RDONLY)) < 0)
  94                         perror_msg_and_die("%s", infile);
  95         } else {
  96                 ifd = STDIN_FILENO;
  97                 infile = "standard input";
  98         }
  99
 100         if (outfile != NULL) {
 101                 oflag = O_WRONLY | O_CREAT;
 102
 103                 if (!seek && trunc)
 104                         oflag |= O_TRUNC;
 105
 106                 if ((ofd = open(outfile, oflag, 0666)) < 0)
 107                         perror_msg_and_die("%s", outfile);
 108
 109                 if (seek && trunc) {
 110                         if (ftruncate(ofd, seek * bs) < 0)
 111                                 perror_msg_and_die("%s", outfile);
 112                 }
 113
 114                 statusfp = stdout;
 115         } else {
 116                 ofd = STDOUT_FILENO;
 117                 outfile = "standard output";
 118                 statusfp = stderr;
 119         }
 120
 121         if (skip) {
 122                 if (lseek(ifd, skip * bs, SEEK_CUR) < 0)
 123                         perror_msg_and_die("%s", infile);
 124         }
 125
 126         if (seek) {
 127                 if (lseek(ofd, seek * bs, SEEK_CUR) < 0)
 128                         perror_msg_and_die("%s", outfile);
 129         }
 130
 131         while (in_full + in_part != count) {
 132                 n = safe_read(ifd, buf, bs);
 133                 if (n < 0)
 134                         perror_msg_and_die("%s", infile);
 135                 if (n == 0)
 136                         break;
 137                 if (n == bs)
 138                         in_full++;
 139                 else
 140                         in_part++;
 141                 if (sync_flag) {
 142                         memset(buf + n, '\0', bs - n);
 143                         n = bs;
 144                 }
 145                 n = full_write(ofd, buf, n);
 146                 if (n < 0)
 147                         perror_msg_and_die("%s", outfile);
 148                 if (n == bs)
 149                         out_full++;
 150                 else
 151                         out_part++;
 152         }
 153
 154         fprintf(statusfp, "%ld+%ld records in\n", (long)in_full, (long)in_part);
 155         fprintf(statusfp, "%ld+%ld records out\n", (long)out_full, (long)out_part);
 156
 157         return EXIT_SUCCESS;
 158 }