ceph/src/tools/rbd/action/MergeDiff.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #define _LARGEFILE64_SOURCE
   5 #include <sys/types.h>
   6 #include <unistd.h>
   7
   8 #include "include/compat.h"
   9 #include "tools/rbd/ArgumentTypes.h"
  10 #include "tools/rbd/Shell.h"
  11 #include "tools/rbd/Utils.h"
  12 #include "common/safe_io.h"
  13 #include "common/debug.h"
  14 #include "common/errno.h"
  15 #include <iostream>
  16 #include <boost/program_options.hpp>
  17
  18 #define dout_context g_ceph_context
  19 #define dout_subsys ceph_subsys_rbd
  20
  21 namespace rbd {
  22 namespace action {
  23 namespace merge_diff {
  24
  25 namespace at = argument_types;
  26 namespace po = boost::program_options;
  27
  28 static int parse_diff_header(int fd, __u8 *tag, string *from, string *to, uint64_t *size)
  29 {
  30   int r;
  31
  32   {//header
  33     char buf[utils::RBD_DIFF_BANNER.size() + 1];
  34     r = safe_read_exact(fd, buf, utils::RBD_DIFF_BANNER.size());
  35     if (r < 0)
  36       return r;
  37
  38     buf[utils::RBD_DIFF_BANNER.size()] = '\0';
  39     if (strcmp(buf, utils::RBD_DIFF_BANNER.c_str())) {
  40       std::cerr << "invalid banner '" << buf << "', expected '"
  41                 << utils::RBD_DIFF_BANNER << "'" << std::endl;
  42       return -EINVAL;
  43     }
  44   }
  45
  46   while (true) {
  47     r = safe_read_exact(fd, tag, 1);
  48     if (r < 0)
  49       return r;
  50
  51     if (*tag == RBD_DIFF_FROM_SNAP) {
  52       r = utils::read_string(fd, 4096, from);   // 4k limit to make sure we don't get a garbage string
  53       if (r < 0)
  54         return r;
  55       dout(2) << " from snap " << *from << dendl;
  56     } else if (*tag == RBD_DIFF_TO_SNAP) {
  57       r = utils::read_string(fd, 4096, to);   // 4k limit to make sure we don't get a garbage string
  58       if (r < 0)
  59         return r;
  60       dout(2) << " to snap " << *to << dendl;
  61     } else if (*tag == RBD_DIFF_IMAGE_SIZE) {
  62       char buf[8];
  63       r = safe_read_exact(fd, buf, 8);
  64       if (r < 0)
  65         return r;
  66
  67       bufferlist bl;
  68       bl.append(buf, 8);
  69       bufferlist::iterator p = bl.begin();
  70       ::decode(*size, p);
  71     } else {
  72       break;
  73     }
  74   }
  75
  76   return 0;
  77 }
  78
  79 static int parse_diff_body(int fd, __u8 *tag, uint64_t *offset, uint64_t *length)
  80 {
  81   int r;
  82
  83   if (!(*tag)) {
  84     r = safe_read_exact(fd, tag, 1);
  85     if (r < 0)
  86       return r;
  87   }
  88
  89   if (*tag == RBD_DIFF_END) {
  90     offset = 0;
  91     length = 0;
  92     return 0;
  93   }
  94
  95   if (*tag != RBD_DIFF_WRITE && *tag != RBD_DIFF_ZERO)
  96     return -ENOTSUP;
  97
  98   char buf[16];
  99   r = safe_read_exact(fd, buf, 16);
 100   if (r < 0)
 101     return r;
 102
 103   bufferlist bl;
 104   bl.append(buf, 16);
 105   bufferlist::iterator p = bl.begin();
 106   ::decode(*offset, p);
 107   ::decode(*length, p);
 108
 109   if (!(*length))
 110     return -ENOTSUP;
 111
 112   return 0;
 113 }
 114
 115 /*
 116  * fd: the diff file to read from
 117  * pd: the diff file to be written into
 118  */
 119 static int accept_diff_body(int fd, int pd, __u8 tag, uint64_t offset, uint64_t length)
 120 {
 121   if (tag == RBD_DIFF_END)
 122     return 0;
 123
 124   bufferlist bl;
 125   ::encode(tag, bl);
 126   ::encode(offset, bl);
 127   ::encode(length, bl);
 128   int r;
 129   r = bl.write_fd(pd);
 130   if (r < 0)
 131     return r;
 132
 133   if (tag == RBD_DIFF_WRITE) {
 134     bufferptr bp = buffer::create(length);
 135     r = safe_read_exact(fd, bp.c_str(), length);
 136     if (r < 0)
 137       return r;
 138     bufferlist data;
 139     data.append(bp);
 140     r = data.write_fd(pd);
 141     if (r < 0)
 142       return r;
 143   }
 144
 145   return 0;
 146 }
 147
 148 /*
 149  * Merge two diff files into one single file
 150  * Note: It does not do the merging work if
 151  * either of the source diff files is stripped,
 152  * since which complicates the process and is
 153  * rarely used
 154  */
 155 static int do_merge_diff(const char *first, const char *second,
 156                          const char *path, bool no_progress)
 157 {
 158   utils::ProgressContext pc("Merging image diff", no_progress);
 159   int fd = -1, sd = -1, pd = -1, r;
 160
 161   string f_from, f_to;
 162   string s_from, s_to;
 163   uint64_t f_size = 0;
 164   uint64_t s_size = 0;
 165   uint64_t pc_size;
 166
 167   __u8 f_tag = 0, s_tag = 0;
 168   uint64_t f_off = 0, f_len = 0;
 169   uint64_t s_off = 0, s_len = 0;
 170   bool f_end = false, s_end = false;
 171
 172   bool first_stdin = !strcmp(first, "-");
 173   if (first_stdin) {
 174     fd = STDIN_FILENO;
 175   } else {
 176     fd = open(first, O_RDONLY);
 177     if (fd < 0) {
 178       r = -errno;
 179       std::cerr << "rbd: error opening " << first << std::endl;
 180       goto done;
 181     }
 182   }
 183
 184   sd = open(second, O_RDONLY);
 185   if (sd < 0) {
 186     r = -errno;
 187     std::cerr << "rbd: error opening " << second << std::endl;
 188     goto done;
 189   }
 190
 191   if (strcmp(path, "-") == 0) {
 192     pd = 1;
 193   } else {
 194     pd = open(path, O_WRONLY | O_CREAT | O_EXCL, 0644);
 195     if (pd < 0) {
 196       r = -errno;
 197       std::cerr << "rbd: error create " << path << std::endl;
 198       goto done;
 199     }
 200   }
 201
 202   //We just handle the case like 'banner, [ftag], [ttag], stag, [wztag]*,etag',
 203   // and the (offset,length) in wztag must be ascending order.
 204   r = parse_diff_header(fd, &f_tag, &f_from, &f_to, &f_size);
 205   if (r < 0) {
 206     std::cerr << "rbd: failed to parse first diff header" << std::endl;
 207     goto done;
 208   }
 209
 210   r = parse_diff_header(sd, &s_tag, &s_from, &s_to, &s_size);
 211   if (r < 0) {
 212     std::cerr << "rbd: failed to parse second diff header" << std::endl;
 213     goto done;
 214   }
 215
 216   if (f_to != s_from) {
 217     r = -EINVAL;
 218     std::cerr << "The first TO snapshot must be equal with the second FROM "
 219               << "snapshot, aborting" << std::endl;
 220     goto done;
 221   }
 222
 223   {
 224     // header
 225     bufferlist bl;
 226     bl.append(utils::RBD_DIFF_BANNER);
 227
 228     __u8 tag;
 229     if (f_from.size()) {
 230       tag = RBD_DIFF_FROM_SNAP;
 231       ::encode(tag, bl);
 232       ::encode(f_from, bl);
 233     }
 234
 235     if (s_to.size()) {
 236       tag = RBD_DIFF_TO_SNAP;
 237       ::encode(tag, bl);
 238       ::encode(s_to, bl);
 239     }
 240
 241     tag = RBD_DIFF_IMAGE_SIZE;
 242     ::encode(tag, bl);
 243     ::encode(s_size, bl);
 244
 245     r = bl.write_fd(pd);
 246     if (r < 0) {
 247       std::cerr << "rbd: failed to write merged diff header" << std::endl;
 248       goto done;
 249     }
 250   }
 251   if (f_size > s_size)
 252     pc_size = f_size << 1;
 253   else
 254     pc_size = s_size << 1;
 255
 256   //data block
 257   while (!f_end || !s_end) {
 258     // progress through input
 259     pc.update_progress(f_off + s_off, pc_size);
 260
 261     if (!f_end && !f_len) {
 262       uint64_t last_off = f_off;
 263
 264       r = parse_diff_body(fd, &f_tag, &f_off, &f_len);
 265       dout(2) << "first diff data chunk: tag=" << f_tag << ", "
 266               << "off=" << f_off << ", "
 267               << "len=" << f_len << dendl;
 268       if (r < 0) {
 269         std::cerr << "rbd: failed to read first diff data chunk header"
 270                   << std::endl;
 271         goto done;
 272       }
 273
 274       if (f_tag == RBD_DIFF_END) {
 275         f_end = true;
 276         f_tag = RBD_DIFF_ZERO;
 277         f_off = f_size;
 278         if (f_size < s_size)
 279           f_len = s_size - f_size;
 280         else
 281           f_len = 0;
 282       }
 283
 284       if (last_off > f_off) {
 285         r = -ENOTSUP;
 286         std::cerr << "rbd: out-of-order offset from first diff ("
 287              << last_off << " > " << f_off << ")" << std::endl;
 288         goto done;
 289       }
 290     }
 291
 292     if (!s_end && !s_len) {
 293       uint64_t last_off = s_off;
 294
 295       r = parse_diff_body(sd, &s_tag, &s_off, &s_len);
 296       dout(2) << "second diff data chunk: tag=" << s_tag << ", "
 297               << "off=" << s_off << ", "
 298               << "len=" << s_len << dendl;
 299       if (r < 0) {
 300         std::cerr << "rbd: failed to read second diff data chunk header"
 301                   << std::endl;
 302         goto done;
 303       }
 304
 305       if (s_tag == RBD_DIFF_END) {
 306         s_end = true;
 307         s_off = s_size;
 308         if (s_size < f_size)
 309           s_len = f_size - s_size;
 310         else
 311           s_len = 0;
 312       }
 313
 314       if (last_off > s_off) {
 315         r = -ENOTSUP;
 316         std::cerr << "rbd: out-of-order offset from second diff ("
 317                   << last_off << " > " << s_off << ")" << std::endl;
 318         goto done;
 319       }
 320     }
 321
 322     if (f_off < s_off && f_len) {
 323       uint64_t delta = s_off - f_off;
 324       if (delta > f_len)
 325         delta = f_len;
 326       r = accept_diff_body(fd, pd, f_tag, f_off, delta);
 327       if (r < 0) {
 328         std::cerr << "rbd: failed to merge diff chunk" << std::endl;
 329         goto done;
 330       }
 331       f_off += delta;
 332       f_len -= delta;
 333
 334       if (!f_len) {
 335         f_tag = 0;
 336         continue;
 337       }
 338     }
 339     assert(f_off >= s_off);
 340
 341     if (f_off < s_off + s_len && f_len) {
 342       uint64_t delta = s_off + s_len - f_off;
 343       if (delta > f_len)
 344         delta = f_len;
 345       if (f_tag == RBD_DIFF_WRITE) {
 346         if (first_stdin) {
 347           bufferptr bp = buffer::create(delta);
 348           r = safe_read_exact(fd, bp.c_str(), delta);
 349         } else {
 350           off64_t l = lseek64(fd, delta, SEEK_CUR);
 351           r = l < 0 ? -errno : 0;
 352         }
 353         if (r < 0) {
 354           std::cerr << "rbd: failed to skip first diff data" << std::endl;
 355           goto done;
 356         }
 357       }
 358       f_off += delta;
 359       f_len -= delta;
 360
 361       if (!f_len) {
 362         f_tag = 0;
 363         continue;
 364       }
 365     }
 366     assert(f_off >= s_off + s_len);
 367     if (s_len) {
 368       r = accept_diff_body(sd, pd, s_tag, s_off, s_len);
 369       if (r < 0) {
 370         std::cerr << "rbd: failed to merge diff chunk" << std::endl;
 371         goto done;
 372       }
 373       s_off += s_len;
 374       s_len = 0;
 375       s_tag = 0;
 376     } else {
 377       assert(f_end && s_end);
 378     }
 379     continue;
 380   }
 381
 382   {//tail
 383     __u8 tag = RBD_DIFF_END;
 384     bufferlist bl;
 385     ::encode(tag, bl);
 386     r = bl.write_fd(pd);
 387   }
 388
 389 done:
 390   if (pd > 2)
 391     close(pd);
 392   if (sd > 2)
 393     close(sd);
 394   if (fd > 2)
 395     close(fd);
 396
 397   if(r < 0) {
 398     pc.fail();
 399     if (pd > 2)
 400       unlink(path);
 401   } else
 402     pc.finish();
 403
 404   return r;
 405 }
 406
 407 void get_arguments(po::options_description *positional,
 408                    po::options_description *options) {
 409   positional->add_options()
 410     ("diff1-path", "path to first diff (or '-' for stdin)")
 411     ("diff2-path", "path to second diff");
 412   at::add_path_options(positional, options,
 413                        "path to merged diff (or '-' for stdout)");
 414   at::add_no_progress_option(options);
 415 }
 416
 417 int execute(const po::variables_map &vm) {
 418   std::string first_diff = utils::get_positional_argument(vm, 0);
 419   if (first_diff.empty()) {
 420     std::cerr << "rbd: first diff was not specified" << std::endl;
 421     return -EINVAL;
 422   }
 423
 424   std::string second_diff = utils::get_positional_argument(vm, 1);
 425   if (second_diff.empty()) {
 426     std::cerr << "rbd: second diff was not specified" << std::endl;
 427     return -EINVAL;
 428   }
 429
 430   std::string path;
 431   int r = utils::get_path(vm, utils::get_positional_argument(vm, 2),
 432                           &path);
 433   if (r < 0) {
 434     return r;
 435   }
 436
 437   r = do_merge_diff(first_diff.c_str(), second_diff.c_str(), path.c_str(),
 438                     vm[at::NO_PROGRESS].as<bool>());
 439   if (r < 0) {
 440     cerr << "rbd: merge-diff error" << std::endl;
 441     return -r;
 442   }
 443
 444   return 0;
 445 }
 446
 447 Shell::Action action(
 448   {"merge-diff"}, {}, "Merge two diff exports together.", "",
 449   &get_arguments, &execute);
 450
 451 } // namespace merge_diff
 452 } // namespace action
 453 } // namespace rbd