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 <signal.h>  // For FEATURE_DD_SIGNAL_HANDLING
  19 #include "busybox.h"
  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 static size_t out_full;
  35 static size_t out_part;
  36 static size_t in_full;
  37 static size_t in_part;
  38
  39 static void dd_output_status(int cur_signal)
  40 {
  41         fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
  42                         (long)in_full, (long)in_part,
  43                         (long)out_full, (long)out_part);
  44 }
  45
  46 int dd_main(int argc, char **argv)
  47 {
  48         size_t count = -1;
  49         size_t bs = 512;
  50         ssize_t n;
  51         off_t seek = 0;
  52         off_t skip = 0;
  53         int sync_flag = FALSE;
  54         int noerror = FALSE;
  55         int trunc_flag = TRUE;
  56         int oflag;
  57         int ifd;
  58         int ofd;
  59         int i;
  60         const char *infile = NULL;
  61         const char *outfile = NULL;
  62         char *buf;
  63
  64         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING)
  65         {
  66                 struct sigaction sa;
  67
  68                 memset(&sa, 0, sizeof(sa));
  69                 sa.sa_handler = dd_output_status;
  70                 sa.sa_flags = SA_RESTART;
  71                 sigemptyset(&sa.sa_mask);
  72                 sigaction(SIGUSR1, &sa, 0);
  73         }
  74
  75         for (i = 1; i < argc; i++) {
  76                 if (strncmp("bs=", argv[i], 3) == 0)
  77                         bs = bb_xparse_number(argv[i]+3, dd_suffixes);
  78                 else if (strncmp("count=", argv[i], 6) == 0)
  79                         count = bb_xparse_number(argv[i]+6, dd_suffixes);
  80                 else if (strncmp("seek=", argv[i], 5) == 0)
  81                         seek = bb_xparse_number(argv[i]+5, dd_suffixes);
  82                 else if (strncmp("skip=", argv[i], 5) == 0)
  83                         skip = bb_xparse_number(argv[i]+5, dd_suffixes);
  84                 else if (strncmp("if=", argv[i], 3) == 0)
  85                         infile = argv[i]+3;
  86                 else if (strncmp("of=", argv[i], 3) == 0)
  87                         outfile = argv[i]+3;
  88                 else if (strncmp("conv=", argv[i], 5) == 0) {
  89                         buf = argv[i]+5;
  90                         while (1) {
  91                                 if (strncmp("notrunc", buf, 7) == 0) {
  92                                         trunc_flag = FALSE;
  93                                         buf += 7;
  94                                 } else if (strncmp("sync", buf, 4) == 0) {
  95                                         sync_flag = TRUE;
  96                                         buf += 4;
  97                                 } else if (strncmp("noerror", buf, 7) == 0) {
  98                                         noerror = TRUE;
  99                                         buf += 7;
 100                                 } else {
 101                                         bb_error_msg_and_die("invalid conversion `%s'", argv[i]+5);
 102                                 }
 103                                 if (buf[0] == '\0')
 104                                         break;
 105                                 if (buf[0] == ',')
 106                                         buf++;
 107                         }
 108                 } else
 109                         bb_show_usage();
 110         }
 111
 112         buf = xmalloc(bs);
 113
 114         if (infile != NULL) {
 115                 ifd = bb_xopen(infile, O_RDONLY);
 116         } else {
 117                 ifd = STDIN_FILENO;
 118                 infile = bb_msg_standard_input;
 119         }
 120
 121         if (outfile != NULL) {
 122                 oflag = O_WRONLY | O_CREAT;
 123
 124                 if (!seek && trunc_flag) {
 125                         oflag |= O_TRUNC;
 126                 }
 127
 128                 ofd = bb_xopen3(outfile, oflag, 0666);
 129
 130                 if (seek && trunc_flag) {
 131                         if (ftruncate(ofd, seek * bs) < 0) {
 132                                 struct stat st;
 133
 134                                 if (fstat (ofd, &st) < 0 || S_ISREG (st.st_mode) ||
 135                                                 S_ISDIR (st.st_mode)) {
 136                                         bb_perror_msg_and_die("%s", outfile);
 137                                 }
 138                         }
 139                 }
 140         } else {
 141                 ofd = STDOUT_FILENO;
 142                 outfile = bb_msg_standard_output;
 143         }
 144
 145         if (skip) {
 146                 if (lseek(ifd, skip * bs, SEEK_CUR) < 0) {
 147                         bb_perror_msg_and_die("%s", infile);
 148                 }
 149         }
 150
 151         if (seek) {
 152                 if (lseek(ofd, seek * bs, SEEK_CUR) < 0) {
 153                         bb_perror_msg_and_die("%s", outfile);
 154                 }
 155         }
 156
 157         while (in_full + in_part != count) {
 158                 if (noerror) {
 159                         /* Pre-zero the buffer when doing the noerror thing */
 160                         memset(buf, '\0', bs);
 161                 }
 162                 n = safe_read(ifd, buf, bs);
 163                 if (n < 0) {
 164                         if (noerror) {
 165                                 n = bs;
 166                                 bb_perror_msg("%s", infile);
 167                         } else {
 168                                 bb_perror_msg_and_die("%s", infile);
 169                         }
 170                 }
 171                 if (n == 0) {
 172                         break;
 173                 }
 174                 if ((size_t)n == bs) {
 175                         in_full++;
 176                 } else {
 177                         in_part++;
 178                 }
 179                 if (sync_flag) {
 180                         memset(buf + n, '\0', bs - n);
 181                         n = bs;
 182                 }
 183                 n = bb_full_write(ofd, buf, n);
 184                 if (n < 0) {
 185                         bb_perror_msg_and_die("%s", outfile);
 186                 }
 187                 if ((size_t)n == bs) {
 188                         out_full++;
 189                 } else {
 190                         out_part++;
 191                 }
 192         }
 193
 194         if (close (ifd) < 0) {
 195                 bb_perror_msg_and_die("%s", infile);
 196         }
 197
 198         if (close (ofd) < 0) {
 199                 bb_perror_msg_and_die("%s", outfile);
 200         }
 201
 202         dd_output_status(0);
 203
 204         return EXIT_SUCCESS;
 205 }