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         { "K", 1024 },  // compat with coreutils dd
  21         { "MD", 1000000 },
  22         { "M", 1048576 },
  23         { "GD", 1000000000 },
  24         { "G", 1073741824 },
  25         { NULL, 0 }
  26 };
  27
  28 static off_t out_full, out_part, in_full, in_part;
  29
  30 static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
  31 {
  32         fprintf(stderr, "%"OFF_FMT"+%"OFF_FMT" records in\n"
  33                         "%"OFF_FMT"+%"OFF_FMT" records out\n",
  34                         in_full, in_part,
  35                         out_full, out_part);
  36 }
  37
  38 static ssize_t full_write_or_warn(int fd, const void *buf, size_t len,
  39                 const char* filename)
  40 {
  41         ssize_t n = full_write(fd, buf, len);
  42         if (n < 0)
  43                 bb_perror_msg("writing '%s'", filename);
  44         return n;
  45 }
  46
  47 int dd_main(int argc, char **argv)
  48 {
  49         enum {
  50                 sync_flag    = 1 << 0,
  51                 noerror      = 1 << 1,
  52                 trunc_flag   = 1 << 2,
  53                 twobufs_flag = 1 << 3,
  54         };
  55         int flags = trunc_flag;
  56         size_t oc = 0, ibs = 512, obs = 512;
  57         ssize_t n, w;
  58         off_t seek = 0, skip = 0, count = OFF_T_MAX;
  59         int oflag, ifd, ofd;
  60         const char *infile = NULL, *outfile = NULL;
  61         char *ibuf, *obuf;
  62
  63         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
  64                 struct sigaction sa;
  65
  66                 memset(&sa, 0, sizeof(sa));
  67                 sa.sa_handler = dd_output_status;
  68                 sa.sa_flags = SA_RESTART;
  69                 sigemptyset(&sa.sa_mask);
  70                 sigaction(SIGUSR1, &sa, 0);
  71         }
  72
  73         for (n = 1; n < argc; n++) {
  74                 char *arg = argv[n];
  75                 /* Must fit into positive ssize_t */
  76                 if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", arg, 4))
  77                         ibs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
  78                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", arg, 4))
  79                         obs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
  80                 else if (!strncmp("bs=", arg, 3))
  81                         ibs = obs = xatoul_range_sfx(arg+3, 0, ((size_t)-1L)/2, dd_suffixes);
  82                 // FIXME: make them capable of eating LARGE numbers
  83                 else if (!strncmp("count=", arg, 6))
  84                         count = xatoul_sfx(arg+6, dd_suffixes);
  85                 else if (!strncmp("seek=", arg, 5))
  86                         seek = xatoul_sfx(arg+5, dd_suffixes);
  87                 else if (!strncmp("skip=", arg, 5))
  88                         skip = xatoul_sfx(arg+5, dd_suffixes);
  89
  90                 else if (!strncmp("if=", arg, 3))
  91                         infile = arg+3;
  92                 else if (!strncmp("of=", arg, 3))
  93                         outfile = arg+3;
  94                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", arg, 5)) {
  95                         arg += 5;
  96                         while (1) {
  97                                 if (!strncmp("notrunc", arg, 7)) {
  98                                         flags &= ~trunc_flag;
  99                                         arg += 7;
 100                                 } else if (!strncmp("sync", arg, 4)) {
 101                                         flags |= sync_flag;
 102                                         arg += 4;
 103                                 } else if (!strncmp("noerror", arg, 7)) {
 104                                         flags |= noerror;
 105                                         arg += 7;
 106                                 } else {
 107                                         bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
 108                                 }
 109                                 if (arg[0] == '\0') break;
 110                                 if (*arg++ != ',') bb_show_usage();
 111                         }
 112                 } else
 113                         bb_show_usage();
 114         }
 115
 116         ibuf = obuf = xmalloc(ibs);
 117         if (ibs != obs) {
 118                 flags |= twobufs_flag;
 119                 obuf = xmalloc(obs);
 120         }
 121
 122         if (infile != NULL)
 123                 ifd = xopen(infile, O_RDONLY);
 124         else {
 125                 ifd = STDIN_FILENO;
 126                 infile = bb_msg_standard_input;
 127         }
 128
 129         if (outfile != NULL) {
 130                 oflag = O_WRONLY | O_CREAT;
 131
 132                 if (!seek && (flags & trunc_flag))
 133                         oflag |= O_TRUNC;
 134
 135                 ofd = xopen3(outfile, oflag, 0666);
 136
 137                 if (seek && (flags & trunc_flag)) {
 138                         if (ftruncate(ofd, seek * obs) < 0) {
 139                                 struct stat st;
 140
 141                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 142                                                 S_ISDIR(st.st_mode))
 143                                         goto die_outfile;
 144                         }
 145                 }
 146         } else {
 147                 ofd = STDOUT_FILENO;
 148                 outfile = bb_msg_standard_output;
 149         }
 150
 151         if (skip) {
 152                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 153                         while (skip-- > 0) {
 154                                 n = safe_read(ifd, ibuf, ibs);
 155                                 if (n < 0)
 156                                         bb_perror_msg_and_die("%s", infile);
 157                                 if (n == 0)
 158                                         break;
 159                         }
 160                 }
 161         }
 162
 163         if (seek) {
 164                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 165                         goto die_outfile;
 166         }
 167
 168         while (in_full + in_part != count) {
 169                 if (flags & noerror) {
 170                         /* Pre-zero the buffer when doing the noerror thing */
 171                         memset(ibuf, '\0', ibs);
 172                 }
 173
 174                 n = safe_read(ifd, ibuf, ibs);
 175                 if (n == 0)
 176                         break;
 177                 if (n < 0) {
 178                         if (flags & noerror) {
 179                                 n = ibs;
 180                                 bb_perror_msg("%s", infile);
 181                         } else
 182                                 bb_perror_msg_and_die("%s", infile);
 183                 }
 184                 if ((size_t)n == ibs)
 185                         in_full++;
 186                 else {
 187                         in_part++;
 188                         if (flags & sync_flag) {
 189                                 memset(ibuf + n, '\0', ibs - n);
 190                                 n = ibs;
 191                         }
 192                 }
 193                 if (flags & twobufs_flag) {
 194                         char *tmp = ibuf;
 195                         while (n) {
 196                                 size_t d = obs - oc;
 197
 198                                 if (d > n)
 199                                         d = n;
 200                                 memcpy(obuf + oc, tmp, d);
 201                                 n -= d;
 202                                 tmp += d;
 203                                 oc += d;
 204                                 if (oc == obs) {
 205                                         w = full_write_or_warn(ofd, obuf, obs, outfile);
 206                                         if (w < 0) goto out_status;
 207                                         if (w == obs)
 208                                                 out_full++;
 209                                         else if (w > 0)
 210                                                 out_part++;
 211                                         oc = 0;
 212                                 }
 213                         }
 214                 } else {
 215                         w = full_write_or_warn(ofd, ibuf, n, outfile);
 216                         if (w < 0) goto out_status;
 217                         if (w == obs)
 218                                 out_full++;
 219                         else if (w > 0)
 220                                 out_part++;
 221                 }
 222         }
 223
 224         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 225                 w = full_write_or_warn(ofd, obuf, oc, outfile);
 226                 if (w < 0) goto out_status;
 227                 if (w > 0)
 228                         out_part++;
 229         }
 230         if (close(ifd) < 0) {
 231                 bb_perror_msg_and_die("%s", infile);
 232         }
 233
 234         if (close(ofd) < 0) {
 235  die_outfile:
 236                 bb_perror_msg_and_die("%s", outfile);
 237         }
 238  out_status:
 239         dd_output_status(0);
 240
 241         return EXIT_SUCCESS;
 242 }