coreutils/dd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini dd implementation for busybox
   4  *
   5  *
   6  * Copyright (C) 2000,2001  Matt Kraai
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9  */
  10
  11 #include <sys/types.h>
  12 #include <sys/stat.h>
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 #include <fcntl.h>
  18 #include "busybox.h"
  19
  20
  21 static const struct suffix_mult dd_suffixes[] = {
  22         { "c", 1 },
  23         { "w", 2 },
  24         { "b", 512 },
  25         { "kD", 1000 },
  26         { "k", 1024 },
  27         { "MD", 1000000 },
  28         { "M", 1048576 },
  29         { "GD", 1000000000 },
  30         { "G", 1073741824 },
  31         { NULL, 0 }
  32 };
  33
  34 int dd_main(int argc, char **argv)
  35 {
  36         size_t out_full = 0;
  37         size_t out_part = 0;
  38         size_t in_full = 0;
  39         size_t in_part = 0;
  40         size_t count = -1;
  41         size_t bs = 512;
  42         ssize_t n;
  43         off_t seek = 0;
  44         off_t skip = 0;
  45         int sync_flag = FALSE;
  46         int noerror = FALSE;
  47         int trunc_flag = TRUE;
  48         int oflag;
  49         int ifd;
  50         int ofd;
  51         int i;
  52         const char *infile = NULL;
  53         const char *outfile = NULL;
  54         char *buf;
  55
  56         for (i = 1; i < argc; i++) {
  57                 if (strncmp("bs=", argv[i], 3) == 0)
  58                         bs = bb_xparse_number(argv[i]+3, dd_suffixes);
  59                 else if (strncmp("count=", argv[i], 6) == 0)
  60                         count = bb_xparse_number(argv[i]+6, dd_suffixes);
  61                 else if (strncmp("seek=", argv[i], 5) == 0)
  62                         seek = bb_xparse_number(argv[i]+5, dd_suffixes);
  63                 else if (strncmp("skip=", argv[i], 5) == 0)
  64                         skip = bb_xparse_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_flag = FALSE;
  74                                         buf += 7;
  75                                 } else if (strncmp("sync", buf, 4) == 0) {
  76                                         sync_flag = TRUE;
  77                                         buf += 4;
  78                                 } else if (strncmp("noerror", buf, 7) == 0) {
  79                                         noerror = TRUE;
  80                                         buf += 7;
  81                                 } else {
  82                                         bb_error_msg_and_die("invalid conversion `%s'", argv[i]+5);
  83                                 }
  84                                 if (buf[0] == '\0')
  85                                         break;
  86                                 if (buf[0] == ',')
  87                                         buf++;
  88                         }
  89                 } else
  90                         bb_show_usage();
  91         }
  92
  93         buf = xmalloc(bs);
  94
  95         if (infile != NULL) {
  96                 ifd = bb_xopen(infile, O_RDONLY);
  97         } else {
  98                 ifd = STDIN_FILENO;
  99                 infile = bb_msg_standard_input;
 100         }
 101
 102         if (outfile != NULL) {
 103                 oflag = O_WRONLY | O_CREAT;
 104
 105                 if (!seek && trunc_flag) {
 106                         oflag |= O_TRUNC;
 107                 }
 108
 109                 ofd = bb_xopen3(outfile, oflag, 0666);
 110
 111                 if (seek && trunc_flag) {
 112                         if (ftruncate(ofd, seek * bs) < 0) {
 113                                 struct stat st;
 114
 115                                 if (fstat (ofd, &st) < 0 || S_ISREG (st.st_mode) ||
 116                                                 S_ISDIR (st.st_mode)) {
 117                                         bb_perror_msg_and_die("%s", outfile);
 118                                 }
 119                         }
 120                 }
 121         } else {
 122                 ofd = STDOUT_FILENO;
 123                 outfile = bb_msg_standard_output;
 124         }
 125
 126         if (skip) {
 127                 if (lseek(ifd, skip * bs, SEEK_CUR) < 0) {
 128                         bb_perror_msg_and_die("%s", infile);
 129                 }
 130         }
 131
 132         if (seek) {
 133                 if (lseek(ofd, seek * bs, SEEK_CUR) < 0) {
 134                         bb_perror_msg_and_die("%s", outfile);
 135                 }
 136         }
 137
 138         while (in_full + in_part != count) {
 139                 if (noerror) {
 140                         /* Pre-zero the buffer when doing the noerror thing */
 141                         memset(buf, '\0', bs);
 142                 }
 143                 n = safe_read(ifd, buf, bs);
 144                 if (n < 0) {
 145                         if (noerror) {
 146                                 n = bs;
 147                                 bb_perror_msg("%s", infile);
 148                         } else {
 149                                 bb_perror_msg_and_die("%s", infile);
 150                         }
 151                 }
 152                 if (n == 0) {
 153                         break;
 154                 }
 155                 if ((size_t)n == bs) {
 156                         in_full++;
 157                 } else {
 158                         in_part++;
 159                 }
 160                 if (sync_flag) {
 161                         memset(buf + n, '\0', bs - n);
 162                         n = bs;
 163                 }
 164                 n = bb_full_write(ofd, buf, n);
 165                 if (n < 0) {
 166                         bb_perror_msg_and_die("%s", outfile);
 167                 }
 168                 if ((size_t)n == bs) {
 169                         out_full++;
 170                 } else {
 171                         out_part++;
 172                 }
 173         }
 174
 175         if (close (ifd) < 0) {
 176                 bb_perror_msg_and_die("%s", infile);
 177         }
 178
 179         if (close (ofd) < 0) {
 180                 bb_perror_msg_and_die("%s", outfile);
 181         }
 182
 183         fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
 184                         (long)in_full, (long)in_part,
 185                         (long)out_full, (long)out_part);
 186
 187         return EXIT_SUCCESS;
 188 }