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"d+%"OFF_FMT"d records in\n"
  33                         "%"OFF_FMT"d+%"OFF_FMT"d 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 #if ENABLE_LFS
  48 #define XATOU_SFX xatoull_sfx
  49 #else
  50 #define XATOU_SFX xatoul_sfx
  51 #endif
  52
  53 int dd_main(int argc, char **argv)
  54 {
  55         enum {
  56                 sync_flag    = 1 << 0,
  57                 noerror      = 1 << 1,
  58                 trunc_flag   = 1 << 2,
  59                 twobufs_flag = 1 << 3,
  60         };
  61         int flags = trunc_flag;
  62         size_t oc = 0, ibs = 512, obs = 512;
  63         ssize_t n, w;
  64         off_t seek = 0, skip = 0, count = OFF_T_MAX;
  65         int oflag, ifd, ofd;
  66         const char *infile = NULL, *outfile = NULL;
  67         char *ibuf, *obuf;
  68
  69         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
  70                 struct sigaction sa;
  71
  72                 memset(&sa, 0, sizeof(sa));
  73                 sa.sa_handler = dd_output_status;
  74                 sa.sa_flags = SA_RESTART;
  75                 sigemptyset(&sa.sa_mask);
  76                 sigaction(SIGUSR1, &sa, 0);
  77         }
  78
  79         for (n = 1; n < argc; n++) {
  80                 char *arg = argv[n];
  81                 /* Must fit into positive ssize_t */
  82                 if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", arg, 4))
  83                         ibs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
  84                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", arg, 4))
  85                         obs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
  86                 else if (!strncmp("bs=", arg, 3))
  87                         ibs = obs = xatoul_range_sfx(arg+3, 0, ((size_t)-1L)/2, dd_suffixes);
  88                 /* These can be large: */
  89                 else if (!strncmp("count=", arg, 6))
  90                         count = XATOU_SFX(arg+6, dd_suffixes);
  91                 else if (!strncmp("seek=", arg, 5))
  92                         seek = XATOU_SFX(arg+5, dd_suffixes);
  93                 else if (!strncmp("skip=", arg, 5))
  94                         skip = XATOU_SFX(arg+5, dd_suffixes);
  95
  96                 else if (!strncmp("if=", arg, 3))
  97                         infile = arg+3;
  98                 else if (!strncmp("of=", arg, 3))
  99                         outfile = arg+3;
 100                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", arg, 5)) {
 101                         arg += 5;
 102                         while (1) {
 103                                 if (!strncmp("notrunc", arg, 7)) {
 104                                         flags &= ~trunc_flag;
 105                                         arg += 7;
 106                                 } else if (!strncmp("sync", arg, 4)) {
 107                                         flags |= sync_flag;
 108                                         arg += 4;
 109                                 } else if (!strncmp("noerror", arg, 7)) {
 110                                         flags |= noerror;
 111                                         arg += 7;
 112                                 } else {
 113                                         bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
 114                                 }
 115                                 if (arg[0] == '\0') break;
 116                                 if (*arg++ != ',') bb_show_usage();
 117                         }
 118                 } else
 119                         bb_show_usage();
 120         }
 121
 122         ibuf = obuf = xmalloc(ibs);
 123         if (ibs != obs) {
 124                 flags |= twobufs_flag;
 125                 obuf = xmalloc(obs);
 126         }
 127
 128         if (infile != NULL)
 129                 ifd = xopen(infile, O_RDONLY);
 130         else {
 131                 ifd = STDIN_FILENO;
 132                 infile = bb_msg_standard_input;
 133         }
 134
 135         if (outfile != NULL) {
 136                 oflag = O_WRONLY | O_CREAT;
 137
 138                 if (!seek && (flags & trunc_flag))
 139                         oflag |= O_TRUNC;
 140
 141                 ofd = xopen(outfile, oflag);
 142
 143                 if (seek && (flags & trunc_flag)) {
 144                         if (ftruncate(ofd, seek * obs) < 0) {
 145                                 struct stat st;
 146
 147                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 148                                                 S_ISDIR(st.st_mode))
 149                                         goto die_outfile;
 150                         }
 151                 }
 152         } else {
 153                 ofd = STDOUT_FILENO;
 154                 outfile = bb_msg_standard_output;
 155         }
 156
 157         if (skip) {
 158                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 159                         while (skip-- > 0) {
 160                                 n = safe_read(ifd, ibuf, ibs);
 161                                 if (n < 0)
 162                                         bb_perror_msg_and_die("%s", infile);
 163                                 if (n == 0)
 164                                         break;
 165                         }
 166                 }
 167         }
 168
 169         if (seek) {
 170                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 171                         goto die_outfile;
 172         }
 173
 174         while (in_full + in_part != count) {
 175                 if (flags & noerror) {
 176                         /* Pre-zero the buffer when doing the noerror thing */
 177                         memset(ibuf, '\0', ibs);
 178                 }
 179
 180                 n = safe_read(ifd, ibuf, ibs);
 181                 if (n == 0)
 182                         break;
 183                 if (n < 0) {
 184                         if (flags & noerror) {
 185                                 n = ibs;
 186                                 bb_perror_msg("%s", infile);
 187                         } else
 188                                 bb_perror_msg_and_die("%s", infile);
 189                 }
 190                 if ((size_t)n == ibs)
 191                         in_full++;
 192                 else {
 193                         in_part++;
 194                         if (flags & sync_flag) {
 195                                 memset(ibuf + n, '\0', ibs - n);
 196                                 n = ibs;
 197                         }
 198                 }
 199                 if (flags & twobufs_flag) {
 200                         char *tmp = ibuf;
 201                         while (n) {
 202                                 size_t d = obs - oc;
 203
 204                                 if (d > n)
 205                                         d = n;
 206                                 memcpy(obuf + oc, tmp, d);
 207                                 n -= d;
 208                                 tmp += d;
 209                                 oc += d;
 210                                 if (oc == obs) {
 211                                         w = full_write_or_warn(ofd, obuf, obs, outfile);
 212                                         if (w < 0) goto out_status;
 213                                         if (w == obs)
 214                                                 out_full++;
 215                                         else if (w > 0)
 216                                                 out_part++;
 217                                         oc = 0;
 218                                 }
 219                         }
 220                 } else {
 221                         w = full_write_or_warn(ofd, ibuf, n, outfile);
 222                         if (w < 0) goto out_status;
 223                         if (w == obs)
 224                                 out_full++;
 225                         else if (w > 0)
 226                                 out_part++;
 227                 }
 228         }
 229
 230         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 231                 w = full_write_or_warn(ofd, obuf, oc, outfile);
 232                 if (w < 0) goto out_status;
 233                 if (w > 0)
 234                         out_part++;
 235         }
 236         if (close(ifd) < 0) {
 237                 bb_perror_msg_and_die("%s", infile);
 238         }
 239
 240         if (close(ofd) < 0) {
 241  die_outfile:
 242                 bb_perror_msg_and_die("%s", outfile);
 243         }
 244  out_status:
 245         dd_output_status(0);
 246
 247         return EXIT_SUCCESS;
 248 }