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 "busybox.h"
  12 #include <signal.h>  /* For FEATURE_DD_SIGNAL_HANDLING */
  13
  14 static const struct suffix_mult dd_suffixes[] = {
  15         { "c", 1 },
  16         { "w", 2 },
  17         { "b", 512 },
  18         { "kD", 1000 },
  19         { "k", 1024 },
  20         { "MD", 1000000 },
  21         { "M", 1048576 },
  22         { "GD", 1000000000 },
  23         { "G", 1073741824 },
  24         { NULL, 0 }
  25 };
  26
  27 static size_t out_full, out_part, in_full, in_part;
  28
  29 static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
  30 {
  31         bb_fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
  32                         (long)in_full, (long)in_part,
  33                         (long)out_full, (long)out_part);
  34 }
  35
  36 int dd_main(int argc, char **argv)
  37 {
  38 #define sync_flag       (1<<0)
  39 #define noerror         (1<<1)
  40 #define trunc_flag      (1<<2)
  41 #define twobufs_flag (1<<3)
  42         int flags = trunc_flag;
  43         size_t count = -1, oc = 0, ibs = 512, obs = 512;
  44         ssize_t n;
  45         off_t seek = 0, skip = 0;
  46         int oflag, ifd, ofd;
  47         const char *infile = NULL, *outfile = NULL;
  48         char *ibuf, *obuf;
  49
  50         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
  51                 struct sigaction sa;
  52
  53                 memset(&sa, 0, sizeof(sa));
  54                 sa.sa_handler = dd_output_status;
  55                 sa.sa_flags = SA_RESTART;
  56                 sigemptyset(&sa.sa_mask);
  57                 sigaction(SIGUSR1, &sa, 0);
  58         }
  59
  60         for (n = 1; n < argc; n++) {
  61                 if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", argv[n], 4)) {
  62                         ibs = bb_xparse_number(argv[n]+4, dd_suffixes);
  63                         flags |= twobufs_flag;
  64                 } else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", argv[n], 4)) {
  65                         obs = bb_xparse_number(argv[n]+4, dd_suffixes);
  66                         flags |= twobufs_flag;
  67                 } else if (!strncmp("bs=", argv[n], 3))
  68                         ibs = obs = bb_xparse_number(argv[n]+3, dd_suffixes);
  69                 else if (!strncmp("count=", argv[n], 6))
  70                         count = bb_xparse_number(argv[n]+6, dd_suffixes);
  71                 else if (!strncmp("seek=", argv[n], 5))
  72                         seek = bb_xparse_number(argv[n]+5, dd_suffixes);
  73                 else if (!strncmp("skip=", argv[n], 5))
  74                         skip = bb_xparse_number(argv[n]+5, dd_suffixes);
  75                 else if (!strncmp("if=", argv[n], 3))
  76                         infile = argv[n]+3;
  77                 else if (!strncmp("of=", argv[n], 3))
  78                         outfile = argv[n]+3;
  79                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", argv[n], 5)) {
  80                         ibuf = argv[n]+5;
  81                         while (1) {
  82                                 if (!strncmp("notrunc", ibuf, 7)) {
  83                                         flags ^= trunc_flag;
  84                                         ibuf += 7;
  85                                 } else if (!strncmp("sync", ibuf, 4)) {
  86                                         flags |= sync_flag;
  87                                         ibuf += 4;
  88                                 } else if (!strncmp("noerror", ibuf, 7)) {
  89                                         flags |= noerror;
  90                                         ibuf += 7;
  91                                 } else {
  92                                         bb_error_msg_and_die(bb_msg_invalid_arg, argv[n]+5, "conv");
  93                                 }
  94                                 if (ibuf[0] == '\0') break;
  95                                 if (ibuf[0] == ',') ibuf++;
  96                         }
  97                 } else
  98                         bb_show_usage();
  99         }
 100         ibuf = xmalloc(ibs);
 101
 102         if (flags & twobufs_flag)
 103                 obuf = xmalloc(obs);
 104         else
 105                 obuf = ibuf;
 106
 107         if (infile != NULL)
 108                 ifd = xopen(infile, O_RDONLY);
 109         else {
 110                 ifd = STDIN_FILENO;
 111                 infile = bb_msg_standard_input;
 112         }
 113
 114         if (outfile != NULL) {
 115                 oflag = O_WRONLY | O_CREAT;
 116
 117                 if (!seek && (flags & trunc_flag))
 118                         oflag |= O_TRUNC;
 119
 120                 ofd = xopen3(outfile, oflag, 0666);
 121
 122                 if (seek && (flags & trunc_flag)) {
 123                         if (ftruncate(ofd, seek * obs) < 0) {
 124                                 struct stat st;
 125
 126                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 127                                                 S_ISDIR(st.st_mode))
 128                                         goto die_outfile;
 129                         }
 130                 }
 131         } else {
 132                 ofd = STDOUT_FILENO;
 133                 outfile = bb_msg_standard_output;
 134         }
 135
 136         if (skip) {
 137                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 138                         while (skip-- > 0) {
 139                                 n = safe_read(ifd, ibuf, ibs);
 140                                 if (n < 0)
 141                                         bb_perror_msg_and_die("%s", infile);
 142                                 if (n == 0)
 143                                         break;
 144                         }
 145                 }
 146         }
 147
 148         if (seek) {
 149                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 150                         goto die_outfile;
 151         }
 152
 153         while (in_full + in_part != count) {
 154                 if (flags & noerror) {
 155                         /* Pre-zero the buffer when doing the noerror thing */
 156                         memset(ibuf, '\0', ibs);
 157                 }
 158
 159                 n = safe_read(ifd, ibuf, ibs);
 160                 if (n == 0)
 161                         break;
 162                 if (n < 0) {
 163                         if (flags & noerror) {
 164                                 n = ibs;
 165                                 bb_perror_msg("%s", infile);
 166                         } else
 167                                 bb_perror_msg_and_die("%s", infile);
 168                 }
 169                 if ((size_t)n == ibs)
 170                         in_full++;
 171                 else {
 172                         in_part++;
 173                         if (sync_flag) {
 174                                 memset(ibuf + n, '\0', ibs - n);
 175                                 n = ibs;
 176                         }
 177                 }
 178                 if (flags & twobufs_flag) {
 179                         char *tmp = ibuf;
 180                         while (n) {
 181                                 size_t d = obs - oc;
 182
 183                                 if (d > n)
 184                                         d = n;
 185                                 memcpy(obuf + oc, tmp, d);
 186                                 n -= d;
 187                                 tmp += d;
 188                                 oc += d;
 189                                 if (oc == obs) {
 190                                         xwrite(ofd, obuf, obs);
 191                                         out_full++;
 192                                         oc = 0;
 193                                 }
 194                         }
 195                 } else {
 196                         xwrite(ofd, ibuf, n);
 197                         if (n == ibs)
 198                                 out_full++;
 199                         else
 200                                 out_part++;
 201                 }
 202         }
 203
 204         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 205                 xwrite(ofd, obuf, oc);
 206                 out_part++;
 207         }
 208         if (close (ifd) < 0) {
 209                 bb_perror_msg_and_die("%s", infile);
 210         }
 211
 212         if (close (ofd) < 0) {
 213 die_outfile:
 214                 bb_perror_msg_and_die("%s", outfile);
 215         }
 216
 217         dd_output_status(0);
 218
 219         return EXIT_SUCCESS;
 220 }