src/bin/lttng-crash/lttng-crash.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <getopt.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <sys/mman.h>
  29 #include <fcntl.h>
  30 #include <sys/wait.h>
  31 #include <unistd.h>
  32 #include <config.h>
  33 #include <ctype.h>
  34 #include <dirent.h>
  35 #include <byteswap.h>
  36 #include <inttypes.h>
  37
  38 #include <version.h>
  39 #include <lttng/lttng.h>
  40 #include <common/common.h>
  41
  42 #define DEFAULT_VIEWER "babeltrace"
  43
  44 #define COPY_BUFLEN             4096
  45 #define RB_CRASH_DUMP_ABI_LEN   32
  46
  47 #define RB_CRASH_DUMP_ABI_MAGIC_LEN     16
  48
  49 /*
  50  * The 128-bit magic number is xor'd in the process data so it does not
  51  * cause a false positive when searching for buffers by scanning memory.
  52  * The actual magic number is:
  53  *   0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1,
  54  *   0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17,
  55  */
  56 #define RB_CRASH_DUMP_ABI_MAGIC_XOR                                     \
  57         {                                                               \
  58                 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF,     \
  59                 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF,     \
  60                 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF,     \
  61                 0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF,     \
  62         }
  63
  64 /*
  65  * Non-static to ensure the compiler does not optimize away the xor.
  66  */
  67 uint8_t lttng_crash_expected_magic_xor[] = RB_CRASH_DUMP_ABI_MAGIC_XOR;
  68
  69 #define RB_CRASH_ENDIAN                 0x1234
  70 #define RB_CRASH_ENDIAN_REVERSE         0x3412
  71
  72 enum lttng_crash_type {
  73         LTTNG_CRASH_TYPE_UST = 0,
  74         LTTNG_CRASH_TYPE_KERNEL = 1,
  75 };
  76
  77 /* LTTng ring buffer defines (copied) */
  78
  79 #define HALF_ULONG_BITS(wl)     (((wl) * CHAR_BIT) >> 1)
  80
  81 #define SB_ID_OFFSET_SHIFT(wl)  (HALF_ULONG_BITS(wl) + 1)
  82 #define SB_ID_OFFSET_COUNT(wl)  (1UL << SB_ID_OFFSET_SHIFT(wl))
  83 #define SB_ID_OFFSET_MASK(wl)   (~(SB_ID_OFFSET_COUNT(wl) - 1))
  84 /*
  85  * Lowest bit of top word half belongs to noref. Used only for overwrite mode.
  86  */
  87 #define SB_ID_NOREF_SHIFT(wl)   (SB_ID_OFFSET_SHIFT(wl) - 1)
  88 #define SB_ID_NOREF_COUNT(wl)   (1UL << SB_ID_NOREF_SHIFT(wl))
  89 #define SB_ID_NOREF_MASK(wl)    SB_ID_NOREF_COUNT(wl)
  90 /*
  91  * In overwrite mode: lowest half of word is used for index.
  92  * Limit of 2^16 subbuffers per buffer on 32-bit, 2^32 on 64-bit.
  93  * In producer-consumer mode: whole word used for index.
  94  */
  95 #define SB_ID_INDEX_SHIFT(wl)   0
  96 #define SB_ID_INDEX_COUNT(wl)   (1UL << SB_ID_INDEX_SHIFT(wl))
  97 #define SB_ID_INDEX_MASK(wl)    (SB_ID_NOREF_COUNT(wl) - 1)
  98
  99 enum rb_modes {
 100         RING_BUFFER_OVERWRITE = 0,      /* Overwrite when buffer full */
 101         RING_BUFFER_DISCARD = 1,        /* Discard when buffer full */
 102 };
 103
 104 struct crash_abi_unknown {
 105         uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN];
 106         uint64_t mmap_length;   /* Overall length of crash record */
 107         uint16_t endian;        /*
 108                                  * { 0x12, 0x34 }: big endian
 109                                  * { 0x34, 0x12 }: little endian
 110                                  */
 111         uint16_t major;         /* Major number. */
 112         uint16_t minor;         /* Minor number. */
 113         uint8_t word_size;      /* Word size (bytes). */
 114         uint8_t layout_type;    /* enum lttng_crash_layout */
 115 } __attribute__((packed));
 116
 117 struct crash_abi_0_0 {
 118         struct crash_abi_unknown parent;
 119
 120         struct {
 121                 uint32_t prod_offset;
 122                 uint32_t consumed_offset;
 123                 uint32_t commit_hot_array;
 124                 uint32_t commit_hot_seq;
 125                 uint32_t buf_wsb_array;
 126                 uint32_t buf_wsb_id;
 127                 uint32_t sb_array;
 128                 uint32_t sb_array_shmp_offset;
 129                 uint32_t sb_backend_p_offset;
 130                 uint32_t content_size;
 131                 uint32_t packet_size;
 132         } __attribute__((packed)) offset;
 133         struct {
 134                 uint8_t prod_offset;
 135                 uint8_t consumed_offset;
 136                 uint8_t commit_hot_seq;
 137                 uint8_t buf_wsb_id;
 138                 uint8_t sb_array_shmp_offset;
 139                 uint8_t sb_backend_p_offset;
 140                 uint8_t content_size;
 141                 uint8_t packet_size;
 142         } __attribute__((packed)) length;
 143         struct {
 144                 uint32_t commit_hot_array;
 145                 uint32_t buf_wsb_array;
 146                 uint32_t sb_array;
 147         } __attribute__((packed)) stride;
 148
 149         uint64_t buf_size;      /* Size of the buffer */
 150         uint64_t subbuf_size;   /* Sub-buffer size */
 151         uint64_t num_subbuf;    /* Number of sub-buffers for writer */
 152         uint32_t mode;          /* Buffer mode: 0: overwrite, 1: discard */
 153 } __attribute__((packed));
 154
 155 struct lttng_crash_layout {
 156         struct {
 157                 int prod_offset, consumed_offset,
 158                         commit_hot_array, commit_hot_seq,
 159                         buf_wsb_array, buf_wsb_id,
 160                         sb_array, sb_array_shmp_offset,
 161                         sb_backend_p_offset, content_size,
 162                         packet_size;
 163         } offset;
 164         struct {
 165                 int prod_offset, consumed_offset,
 166                         commit_hot_seq, buf_wsb_id,
 167                         sb_array_shmp_offset, sb_backend_p_offset,
 168                         content_size, packet_size;
 169         } length;
 170         struct {
 171                 int commit_hot_array, buf_wsb_array, sb_array;
 172         } stride;
 173
 174         int reverse_byte_order;
 175         int word_size;
 176
 177         uint64_t mmap_length;   /* Length of crash record */
 178         uint64_t buf_size;      /* Size of the buffer */
 179         uint64_t subbuf_size;   /* Sub-buffer size */
 180         uint64_t num_subbuf;    /* Number of sub-buffers for writer */
 181         uint32_t mode;          /* Buffer mode: 0: overwrite, 1: discard */
 182 };
 183
 184 /* Variables */
 185 static char *progname,
 186         *opt_viewer_path = NULL,
 187         *opt_output_path = NULL;
 188
 189 static char *input_path;
 190
 191 int lttng_opt_quiet, lttng_opt_verbose, lttng_opt_mi;
 192
 193 enum {
 194         OPT_DUMP_OPTIONS,
 195 };
 196
 197 /* Getopt options. No first level command. */
 198 static struct option long_options[] = {
 199         { "version",            0, NULL, 'V' },
 200         { "help",               0, NULL, 'h' },
 201         { "verbose",            0, NULL, 'v' },
 202         { "viewer",             1, NULL, 'e' },
 203         { "extract",            1, NULL, 'x' },
 204         { "list-options",       0, NULL, OPT_DUMP_OPTIONS },
 205         { NULL, 0, NULL, 0 },
 206 };
 207
 208 static void usage(FILE *ofp)
 209 {
 210         fprintf(ofp, "LTTng Crash Trace Viewer " VERSION " - " VERSION_NAME "%s\n\n",
 211                 GIT_VERSION[0] == '\0' ? "" : " - " GIT_VERSION);
 212         fprintf(ofp, "usage: lttng-crash [OPTIONS] FILE\n");
 213         fprintf(ofp, "\n");
 214         fprintf(ofp, "Options:\n");
 215         fprintf(ofp, "  -V, --version              Show version.\n");
 216         fprintf(ofp, "  -h, --help                 Show this help.\n");
 217         fprintf(ofp, "      --list-options         Simple listing of lttng-crash options.\n");
 218         fprintf(ofp, "  -v, --verbose              Increase verbosity.\n");
 219         fprintf(ofp, "  -e, --viewer               Specify viewer and/or options to use. This will\n"
 220                      "                             completely override the default viewers so please\n"
 221                      "                             make sure to specify the full command. The trace\n"
 222                      "                             directory paths appended at the end to the\n"
 223                      "                             arguments.\n");
 224         fprintf(ofp, "  -x, --extract PATH         Extract trace(s) to specified path. Don't view\n"
 225                      "                             trace.\n");
 226         fprintf(ofp, "\n");
 227         fprintf(ofp, "Please see the lttng-crash(1) man page for full documentation.\n");
 228         fprintf(ofp, "See http://lttng.org for updates, bug reports and news.\n");
 229 }
 230
 231 static void version(FILE *ofp)
 232 {
 233         fprintf(ofp, "%s (LTTng Crash Trace Viewer) " VERSION " - " VERSION_NAME
 234 "%s\n",
 235                         progname,
 236                         GIT_VERSION[0] == '\0' ? "" : " - " GIT_VERSION);
 237 }
 238
 239 /*
 240  *  list_options
 241  *
 242  *  List options line by line. This is mostly for bash auto completion and to
 243  *  avoid difficult parsing.
 244  */
 245 static void list_options(FILE *ofp)
 246 {
 247         int i = 0;
 248         struct option *option = NULL;
 249
 250         option = &long_options[i];
 251         while (option->name != NULL) {
 252                 fprintf(ofp, "--%s\n", option->name);
 253
 254                 if (isprint(option->val)) {
 255                         fprintf(ofp, "-%c\n", option->val);
 256                 }
 257
 258                 i++;
 259                 option = &long_options[i];
 260         }
 261 }
 262
 263 /*
 264  * Parse command line arguments.
 265  *
 266  * Return 0 if OK, else -1
 267  */
 268 static int parse_args(int argc, char **argv)
 269 {
 270         int opt, ret = 0;
 271
 272         if (argc < 2) {
 273                 usage(stderr);
 274                 exit(EXIT_FAILURE);
 275         }
 276
 277         while ((opt = getopt_long(argc, argv, "+Vhve:x:", long_options, NULL)) != -1) {
 278                 switch (opt) {
 279                 case 'V':
 280                         version(stdout);
 281                         ret = 1;
 282                         goto end;
 283                 case 'h':
 284                         usage(stdout);
 285                         ret = 1;
 286                         goto end;
 287                 case 'v':
 288                         /* There is only 3 possible level of verbosity. (-vvv) */
 289                         if (lttng_opt_verbose < 3) {
 290                                 lttng_opt_verbose += 1;
 291                         }
 292                         break;
 293                 case 'e':
 294                         free(opt_viewer_path);
 295                         opt_viewer_path = strdup(optarg);
 296                         break;
 297                 case 'x':
 298                         free(opt_output_path);
 299                         opt_output_path = strdup(optarg);
 300                         break;
 301                 case OPT_DUMP_OPTIONS:
 302                         list_options(stdout);
 303                         ret = 1;
 304                         goto end;
 305                 default:
 306                         usage(stderr);
 307                         goto error;
 308                 }
 309         }
 310
 311         if (!opt_viewer_path) {
 312                 opt_viewer_path = DEFAULT_VIEWER;
 313         }
 314
 315         /* No leftovers, or more than one input path, print usage and quit */
 316         if ((argc - optind) == 0 || (argc - optind) > 1) {
 317                 usage(stderr);
 318                 goto error;
 319         }
 320
 321         input_path = argv[optind];
 322 end:
 323         return ret;
 324
 325 error:
 326         return -1;
 327 }
 328
 329 static
 330 int copy_file(const char *file_dest, const char *file_src)
 331 {
 332         int fd_src = -1, fd_dest = -1;
 333         ssize_t readlen, writelen;
 334         char buf[COPY_BUFLEN];
 335         int ret;
 336
 337         DBG("Copy metadata file '%s' into '%s'", file_src, file_dest);
 338
 339         fd_src = open(file_src, O_RDONLY);
 340         if (fd_src < 0) {
 341                 PERROR("Error opening %s for reading", file_src);
 342                 ret = -errno;
 343                 goto error;
 344         }
 345         fd_dest = open(file_dest, O_RDWR | O_CREAT | O_EXCL,
 346                         S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
 347         if (fd_dest < 0) {
 348                 PERROR("Error opening %s for writing", file_dest);
 349                 ret = -errno;
 350                 goto error;
 351         }
 352
 353         for (;;) {
 354                 readlen = lttng_read(fd_src, buf, COPY_BUFLEN);
 355                 if (readlen < 0) {
 356                         PERROR("Error reading input file");
 357                         ret = -1;
 358                         goto error;
 359                 }
 360                 if (!readlen) {
 361                         break;
 362                 }
 363                 writelen = lttng_write(fd_dest, buf, readlen);
 364                 if (writelen < readlen) {
 365                         PERROR("Error writing to output file");
 366                         ret = -1;
 367                         goto error;
 368                 }
 369         }
 370
 371         ret = 0;
 372 error:
 373         if (fd_src >= 0) {
 374                 if (close(fd_src) < 0) {
 375                         PERROR("Error closing %s", file_src);
 376                 }
 377         }
 378
 379         if (fd_dest >= 0) {
 380                 if (close(fd_dest) < 0) {
 381                         PERROR("Error closing %s", file_dest);
 382                 }
 383         }
 384         return ret;
 385 }
 386
 387 static
 388 uint64_t _crash_get_field(const struct lttng_crash_layout *layout,
 389                 const char *ptr, size_t size)
 390 {
 391         switch (size) {
 392         case 1: return *(uint8_t *) ptr;
 393         case 2: if (layout->reverse_byte_order) {
 394                         return __bswap_16(*(uint16_t *) ptr);
 395                 } else {
 396                         return *(uint16_t *) ptr;
 397
 398                 }
 399         case 4: if (layout->reverse_byte_order) {
 400                         return __bswap_32(*(uint32_t *) ptr);
 401                 } else {
 402                         return *(uint32_t *) ptr;
 403
 404                 }
 405         case 8: if (layout->reverse_byte_order) {
 406                         return __bswap_64(*(uint64_t *) ptr);
 407                 } else {
 408                         return *(uint64_t *) ptr;
 409                 }
 410         default:
 411                 abort();
 412                 return -1;
 413         }
 414
 415 }
 416
 417 #define crash_get_field(layout, map, name)                              \
 418         _crash_get_field(layout, (map) + (layout)->offset.name,         \
 419                 layout->length.name)
 420
 421 #define crash_get_array_field(layout, map, array_name, idx, field_name) \
 422         _crash_get_field(layout,                                        \
 423                 (map) + (layout)->offset.array_name                     \
 424                         + (idx * (layout)->stride.array_name)           \
 425                         + (layout)->offset.field_name,                  \
 426                 (layout)->length.field_name)
 427
 428 #define crash_get_hdr_raw_field(layout, hdr, name)      ((hdr)->name)
 429
 430 #define crash_get_hdr_field(layout, hdr, name)                          \
 431         _crash_get_field(layout, (const char *) &(hdr)->name,           \
 432                 sizeof((hdr)->name))
 433
 434 #define crash_get_layout(layout, hdr, name)                             \
 435         do {                                                            \
 436                 (layout)->name = crash_get_hdr_field(layout, hdr,       \
 437                                         name);                          \
 438                 DBG("layout.%s = %" PRIu64, #name,                      \
 439                         (uint64_t) (layout)->name);                     \
 440         } while (0)
 441
 442 static
 443 int get_crash_layout_0_0(struct lttng_crash_layout *layout,
 444                 char *map)
 445 {
 446         const struct crash_abi_0_0 *abi = (const struct crash_abi_0_0 *) map;
 447
 448         crash_get_layout(layout, abi, offset.prod_offset);
 449         crash_get_layout(layout, abi, offset.consumed_offset);
 450         crash_get_layout(layout, abi, offset.commit_hot_array);
 451         crash_get_layout(layout, abi, offset.commit_hot_seq);
 452         crash_get_layout(layout, abi, offset.buf_wsb_array);
 453         crash_get_layout(layout, abi, offset.buf_wsb_id);
 454         crash_get_layout(layout, abi, offset.sb_array);
 455         crash_get_layout(layout, abi, offset.sb_array_shmp_offset);
 456         crash_get_layout(layout, abi, offset.sb_backend_p_offset);
 457         crash_get_layout(layout, abi, offset.content_size);
 458         crash_get_layout(layout, abi, offset.packet_size);
 459
 460         crash_get_layout(layout, abi, length.prod_offset);
 461         crash_get_layout(layout, abi, length.consumed_offset);
 462         crash_get_layout(layout, abi, length.commit_hot_seq);
 463         crash_get_layout(layout, abi, length.buf_wsb_id);
 464         crash_get_layout(layout, abi, length.sb_array_shmp_offset);
 465         crash_get_layout(layout, abi, length.sb_backend_p_offset);
 466         crash_get_layout(layout, abi, length.content_size);
 467         crash_get_layout(layout, abi, length.packet_size);
 468
 469         crash_get_layout(layout, abi, stride.commit_hot_array);
 470         crash_get_layout(layout, abi, stride.buf_wsb_array);
 471         crash_get_layout(layout, abi, stride.sb_array);
 472
 473         crash_get_layout(layout, abi, buf_size);
 474         crash_get_layout(layout, abi, subbuf_size);
 475         crash_get_layout(layout, abi, num_subbuf);
 476         crash_get_layout(layout, abi, mode);
 477
 478         return 0;
 479 }
 480
 481 static
 482 void print_dbg_magic(const uint8_t *magic)
 483 {
 484         DBG("magic: 0x%X%X%X%X%X%X%X%X%X%X%X%X%X%X%X%X",
 485                 magic[0], magic[1], magic[2], magic[3],
 486                 magic[4], magic[5], magic[6], magic[7],
 487                 magic[8], magic[9], magic[10], magic[11],
 488                 magic[12], magic[13], magic[14], magic[15]);
 489 }
 490
 491 static
 492 int check_magic(const uint8_t *magic)
 493 {
 494         int i;
 495
 496         for (i = 0; i < RB_CRASH_DUMP_ABI_MAGIC_LEN; i++) {
 497                 if ((magic[i] ^ 0xFF) != lttng_crash_expected_magic_xor[i]) {
 498                         return -1;
 499                 }
 500         }
 501         return 0;
 502 }
 503
 504 static
 505 int get_crash_layout(struct lttng_crash_layout *layout, int fd)
 506 {
 507         char *map;
 508         int ret = 0, unmapret;
 509         const uint8_t *magic;
 510         uint64_t mmap_length;
 511         uint16_t major, minor;
 512         uint8_t word_size;
 513         const struct crash_abi_unknown *abi;
 514         uint16_t endian;
 515         enum lttng_crash_type layout_type;
 516
 517         map = mmap(NULL, RB_CRASH_DUMP_ABI_LEN, PROT_READ, MAP_PRIVATE,
 518                 fd, 0);
 519         if (map == MAP_FAILED) {
 520                 PERROR("Mapping file");
 521                 return -1;
 522         }
 523         abi = (const struct crash_abi_unknown *) map;
 524         magic = crash_get_hdr_raw_field(layout, abi, magic);
 525         print_dbg_magic(magic);
 526         if (check_magic(magic)) {
 527                 DBG("Unknown magic number");
 528                 ret = 1;        /* positive return value, skip */
 529                 goto end;
 530         }
 531         endian = crash_get_hdr_field(layout, abi, endian);
 532         switch (endian) {
 533         case RB_CRASH_ENDIAN:
 534                 break;
 535         case RB_CRASH_ENDIAN_REVERSE:
 536                 layout->reverse_byte_order = 1;
 537                 break;
 538         default:
 539                 DBG("Unknown endianness value: 0x%X", (unsigned int) endian);
 540                 ret = 1;        /* positive return value, skip */
 541                 goto end;
 542         }
 543         layout_type = (enum lttng_crash_type) crash_get_hdr_field(layout, abi, layout_type);
 544         switch (layout_type) {
 545         case LTTNG_CRASH_TYPE_UST:
 546                 break;
 547         case LTTNG_CRASH_TYPE_KERNEL:
 548                 ERR("lttng-modules buffer layout support not implemented");
 549                 ret = 1;        /* positive return value, skip */
 550                 goto end;
 551         default:
 552                 ERR("Unknown layout type %u", (unsigned int) layout_type);
 553                 ret = 1;        /* positive return value, skip */
 554                 goto end;
 555         }
 556         mmap_length = crash_get_hdr_field(layout, abi, mmap_length);
 557         DBG("mmap_length: %" PRIu64, mmap_length);
 558         layout->mmap_length = mmap_length;
 559         major = crash_get_hdr_field(layout, abi, major);
 560         DBG("major: %u", major);
 561         minor = crash_get_hdr_field(layout, abi, minor);
 562         DBG("minor: %u", minor);
 563         word_size = crash_get_hdr_field(layout, abi, word_size);
 564         DBG("word_size: %u", word_size);
 565         switch (major) {
 566         case 0:
 567                 switch (minor) {
 568                 case 0:
 569                         ret = get_crash_layout_0_0(layout, map);
 570                         if (ret)
 571                                 goto end;
 572                         break;
 573                 default:
 574                         ret = -1;
 575                         ERR("Unsupported crash ABI %u.%u\n", major, minor);
 576                         goto end;
 577                 }
 578                 break;
 579         default:
 580                 ERR("Unsupported crash ABI %u.%u\n", major, minor);
 581                 ret = -1;
 582                 goto end;
 583         }
 584         layout->word_size = word_size;
 585 end:
 586         unmapret = munmap(map, RB_CRASH_DUMP_ABI_LEN);
 587         if (unmapret) {
 588                 PERROR("munmap");
 589         }
 590         return ret;
 591 }
 592
 593 /* buf_trunc mask selects only the buffer number. */
 594 static inline
 595 uint64_t buf_trunc(uint64_t offset, uint64_t buf_size)
 596 {
 597         return offset & ~(buf_size - 1);
 598 }
 599
 600 /* subbuf_trunc mask selects the subbuffer number. */
 601 static inline
 602 uint64_t subbuf_trunc(uint64_t offset, uint64_t subbuf_size)
 603 {
 604         return offset & ~(subbuf_size - 1);
 605 }
 606
 607 /* buf_offset mask selects only the offset within the current buffer. */
 608 static inline
 609 uint64_t buf_offset(uint64_t offset, uint64_t buf_size)
 610 {
 611         return offset & (buf_size - 1);
 612 }
 613
 614 /* subbuf_offset mask selects the offset within the current subbuffer. */
 615 static inline
 616 uint64_t subbuf_offset(uint64_t offset, uint64_t subbuf_size)
 617 {
 618         return offset & (subbuf_size - 1);
 619 }
 620
 621 /* subbuf_index returns the index of the current subbuffer within the buffer. */
 622 static inline
 623 uint64_t subbuf_index(uint64_t offset, uint64_t buf_size, uint64_t subbuf_size)
 624 {
 625         return buf_offset(offset, buf_size) / subbuf_size;
 626 }
 627
 628 static inline
 629 uint64_t subbuffer_id_get_index(uint32_t mode, uint64_t id,
 630                 unsigned int wl)
 631 {
 632         if (mode == RING_BUFFER_OVERWRITE)
 633                 return id & SB_ID_INDEX_MASK(wl);
 634         else
 635                 return id;
 636 }
 637
 638 static
 639 int copy_crash_subbuf(const struct lttng_crash_layout *layout,
 640                 int fd_dest, char *buf, uint64_t offset)
 641 {
 642         uint64_t buf_size, subbuf_size, num_subbuf, sbidx, id,
 643                 sb_bindex, rpages_offset, p_offset, seq_cc,
 644                 committed, commit_count_mask, consumed_cur,
 645                 packet_size;
 646         char *subbuf_ptr;
 647         ssize_t writelen;
 648
 649         /*
 650          * Get the current subbuffer by applying the proper mask to
 651          * "offset", and looking up the subbuf location within the
 652          * source file buf.
 653          */
 654
 655         buf_size = layout->buf_size;
 656         subbuf_size = layout->subbuf_size;
 657         num_subbuf = layout->num_subbuf;
 658
 659         switch (layout->word_size) {
 660         case 4: commit_count_mask = 0xFFFFFFFFULL / num_subbuf;
 661                 break;
 662         case 8: commit_count_mask = 0xFFFFFFFFFFFFFFFFULL / num_subbuf;
 663                 break;
 664         default:
 665                 ERR("Unsupported word size: %u",
 666                         (unsigned int) layout->word_size);
 667                 return -EINVAL;
 668         }
 669
 670         DBG("Copy crash subbuffer at offset %" PRIu64, offset);
 671         sbidx = subbuf_index(offset, buf_size, subbuf_size);
 672
 673         /*
 674          * Find where the seq cc is located. Compute length of data to
 675          * copy.
 676          */
 677         seq_cc = crash_get_array_field(layout, buf, commit_hot_array,
 678                 sbidx, commit_hot_seq);
 679         consumed_cur = crash_get_field(layout, buf, consumed_offset);
 680
 681         /*
 682          * Check that the buffer we are getting is after or at
 683          * consumed_cur position.
 684          */
 685         if ((long) subbuf_trunc(offset, subbuf_size)
 686                         - (long) subbuf_trunc(consumed_cur, subbuf_size) < 0) {
 687                 DBG("No data: position is before consumed_cur");
 688                 goto nodata;
 689         }
 690
 691         /*
 692          * Check if subbuffer has been fully committed.
 693          */
 694         if (((seq_cc - subbuf_size) & commit_count_mask)
 695                         - (buf_trunc(offset, buf_size) / num_subbuf)
 696                         == 0) {
 697                 committed = subbuf_size;
 698         } else {
 699                 committed = subbuf_offset(seq_cc, subbuf_size);
 700                 if (!committed) {
 701                         DBG("No data committed, seq_cc: %" PRIu64, seq_cc);
 702                         goto nodata;
 703                 }
 704         }
 705
 706         /* Find actual physical offset in subbuffer table */
 707         id = crash_get_array_field(layout, buf, buf_wsb_array,
 708                 sbidx, buf_wsb_id);
 709         sb_bindex = subbuffer_id_get_index(layout->mode, id,
 710                 layout->word_size);
 711         rpages_offset = crash_get_array_field(layout, buf, sb_array,
 712                 sb_bindex, sb_array_shmp_offset);
 713         p_offset = crash_get_field(layout, buf + rpages_offset,
 714                 sb_backend_p_offset);
 715         subbuf_ptr = buf + p_offset;
 716
 717         if (committed == subbuf_size) {
 718                 /*
 719                  * Packet header can be used.
 720                  */
 721                 if (layout->length.packet_size) {
 722                         memcpy(&packet_size,
 723                                 subbuf_ptr + layout->offset.packet_size,
 724                                 layout->length.packet_size);
 725                         if (layout->reverse_byte_order) {
 726                                 packet_size = __bswap_64(packet_size);
 727                         }
 728                         packet_size /= CHAR_BIT;
 729                 } else {
 730                         packet_size = subbuf_size;
 731                 }
 732         } else {
 733                 uint64_t patch_size;
 734
 735                 /*
 736                  * Find where to patch the sub-buffer header with actual
 737                  * readable data len and packet len, derived from seq
 738                  * cc. Patch it in our in-memory copy.
 739                  */
 740                 patch_size = committed * CHAR_BIT;
 741                 if (layout->reverse_byte_order) {
 742                         patch_size = __bswap_64(patch_size);
 743                 }
 744                 if (layout->length.content_size) {
 745                         memcpy(subbuf_ptr + layout->offset.content_size,
 746                                 &patch_size, layout->length.content_size);
 747                 }
 748                 if (layout->length.packet_size) {
 749                         memcpy(subbuf_ptr + layout->offset.packet_size,
 750                                 &patch_size, layout->length.packet_size);
 751                 }
 752                 packet_size = committed;
 753         }
 754
 755         /*
 756          * Copy packet into fd_dest.
 757          */
 758         writelen = lttng_write(fd_dest, subbuf_ptr, packet_size);
 759         if (writelen < packet_size) {
 760                 PERROR("Error writing to output file");
 761                 return -1;
 762         }
 763         DBG("Copied %" PRIu64 " bytes of data", packet_size);
 764         return 0;
 765
 766 nodata:
 767         return -ENODATA;
 768 }
 769
 770 static
 771 int copy_crash_data(const struct lttng_crash_layout *layout, int fd_dest,
 772                 int fd_src)
 773 {
 774         char *buf;
 775         int ret = 0, has_data = 0;
 776         struct stat statbuf;
 777         size_t src_file_len;
 778         uint64_t prod_offset, consumed_offset;
 779         uint64_t offset, subbuf_size;
 780         ssize_t readlen;
 781
 782         ret = fstat(fd_src, &statbuf);
 783         if (ret) {
 784                 return ret;
 785         }
 786         src_file_len = layout->mmap_length;
 787         buf = zmalloc(src_file_len);
 788         if (!buf) {
 789                 return -1;
 790         }
 791         readlen = lttng_read(fd_src, buf, src_file_len);
 792         if (readlen < 0) {
 793                 PERROR("Error reading input file");
 794                 ret = -1;
 795                 goto end;
 796         }
 797
 798         prod_offset = crash_get_field(layout, buf, prod_offset);
 799         DBG("prod_offset: 0x%" PRIx64, prod_offset);
 800         consumed_offset = crash_get_field(layout, buf, consumed_offset);
 801         DBG("consumed_offset: 0x%" PRIx64, consumed_offset);
 802         subbuf_size = layout->subbuf_size;
 803
 804         for (offset = consumed_offset; offset < prod_offset;
 805                         offset += subbuf_size) {
 806                 ret = copy_crash_subbuf(layout, fd_dest, buf, offset);
 807                 if (!ret) {
 808                         has_data = 1;
 809                 }
 810                 if (ret) {
 811                         goto end;
 812                 }
 813         }
 814 end:
 815         free(buf);
 816         if (ret && ret != -ENODATA) {
 817                 return ret;
 818         }
 819         if (has_data) {
 820                 return 0;
 821         } else {
 822                 return -ENODATA;
 823         }
 824 }
 825
 826 static
 827 int extract_file(int output_dir_fd, const char *output_file,
 828                 int input_dir_fd, const char *input_file)
 829 {
 830         int fd_dest, fd_src, ret = 0, closeret;
 831         struct lttng_crash_layout layout;
 832
 833         layout.reverse_byte_order = 0;  /* For reading magic number */
 834
 835         DBG("Extract file '%s'", input_file);
 836         fd_src = openat(input_dir_fd, input_file, O_RDONLY);
 837         if (fd_src < 0) {
 838                 PERROR("Error opening '%s' for reading",
 839                         input_file);
 840                 ret = -1;
 841                 goto end;
 842         }
 843
 844         /* Query the crash ABI layout */
 845         ret = get_crash_layout(&layout, fd_src);
 846         if (ret) {
 847                 goto close_src;
 848         }
 849
 850         fd_dest = openat(output_dir_fd, output_file,
 851                         O_RDWR | O_CREAT | O_EXCL,
 852                         S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
 853         if (fd_dest < 0) {
 854                 PERROR("Error opening '%s' for writing",
 855                         output_file);
 856                 ret = -1;
 857                 goto close_src;
 858         }
 859
 860         ret = copy_crash_data(&layout, fd_dest, fd_src);
 861         if (ret) {
 862                 goto close_dest;
 863         }
 864
 865 close_dest:
 866         closeret = close(fd_dest);
 867         if (closeret) {
 868                 PERROR("close");
 869         }
 870         if (ret == -ENODATA) {
 871                 closeret = unlinkat(output_dir_fd, output_file, 0);
 872                 if (closeret) {
 873                         PERROR("unlinkat");
 874                 }
 875         }
 876 close_src:
 877         closeret = close(fd_src);
 878         if (closeret) {
 879                 PERROR("close");
 880         }
 881 end:
 882         return ret;
 883 }
 884
 885 static
 886 int extract_all_files(const char *output_path,
 887                 const char *input_path)
 888 {
 889         DIR *input_dir, *output_dir;
 890         int input_dir_fd, output_dir_fd, ret = 0, closeret;
 891         struct dirent *entry;   /* input */
 892
 893         /* Open input directory */
 894         input_dir = opendir(input_path);
 895         if (!input_dir) {
 896                 PERROR("Cannot open '%s' path", input_path);
 897                 return -1;
 898         }
 899         input_dir_fd = dirfd(input_dir);
 900         if (input_dir_fd < 0) {
 901                 PERROR("dirfd");
 902                 return -1;
 903         }
 904
 905         /* Open output directory */
 906         output_dir = opendir(output_path);
 907         if (!output_dir) {
 908                 PERROR("Cannot open '%s' path", output_path);
 909                 return -1;
 910         }
 911         output_dir_fd = dirfd(output_dir);
 912         if (output_dir_fd < 0) {
 913                 PERROR("dirfd");
 914                 return -1;
 915         }
 916
 917         while ((entry = readdir(input_dir))) {
 918                 if (!strcmp(entry->d_name, ".")
 919                                 || !strcmp(entry->d_name, ".."))
 920                         continue;
 921                 ret = extract_file(output_dir_fd, entry->d_name,
 922                         input_dir_fd, entry->d_name);
 923                 if (ret == -ENODATA) {
 924                         DBG("No data in file '%s', skipping", entry->d_name);
 925                         ret = 0;
 926                         continue;
 927                 } else if (ret < 0) {
 928                         break;
 929                 } else if (ret > 0) {
 930                         DBG("Skipping file '%s'", entry->d_name);
 931                         ret = 0;
 932                         continue;
 933                 }
 934         }
 935         closeret = closedir(output_dir);
 936         if (closeret) {
 937                 PERROR("closedir");
 938         }
 939         closeret = closedir(input_dir);
 940         if (closeret) {
 941                 PERROR("closedir");
 942         }
 943         return ret;
 944 }
 945
 946 static
 947 int extract_one_trace(const char *output_path,
 948                 const char *input_path)
 949 {
 950         char dest[PATH_MAX], src[PATH_MAX];
 951         int ret;
 952
 953         DBG("Extract crash trace '%s' into '%s'", input_path, output_path);
 954
 955         /* Copy metadata */
 956         strncpy(dest, output_path, PATH_MAX);
 957         dest[PATH_MAX - 1] = '\0';
 958         strncat(dest, "/metadata", PATH_MAX - strlen(dest) - 1);
 959
 960         strncpy(src, input_path, PATH_MAX);
 961         src[PATH_MAX - 1] = '\0';
 962         strncat(src, "/metadata", PATH_MAX - strlen(dest) - 1);
 963
 964         ret = copy_file(dest, src);
 965         if (ret) {
 966                 return ret;
 967         }
 968
 969         /* Extract each other file that has expected header */
 970         return extract_all_files(output_path, input_path);
 971 }
 972
 973 static
 974 int extract_trace_recursive(const char *output_path,
 975                 const char *input_path)
 976 {
 977         DIR *dir;
 978         int dir_fd, ret = 0, closeret;
 979         struct dirent *entry;
 980         size_t path_len;
 981         int has_warning = 0;
 982
 983         /* Open directory */
 984         dir = opendir(input_path);
 985         if (!dir) {
 986                 PERROR("Cannot open '%s' path", input_path);
 987                 return -1;
 988         }
 989
 990         path_len = strlen(input_path);
 991
 992         dir_fd = dirfd(dir);
 993         if (dir_fd < 0) {
 994                 PERROR("dirfd");
 995                 return -1;
 996         }
 997
 998         while ((entry = readdir(dir))) {
 999                 struct stat st;
1000                 size_t name_len;
1001                 char filename[PATH_MAX];
1002
1003                 if (!strcmp(entry->d_name, ".")
1004                                 || !strcmp(entry->d_name, "..")) {
1005                         continue;
1006                 }
1007
1008                 name_len = strlen(entry->d_name);
1009                 if (path_len + name_len + 2 > sizeof(filename)) {
1010                         ERR("Failed to remove file: path name too long (%s/%s)",
1011                                 input_path, entry->d_name);
1012                         continue;
1013                 }
1014
1015                 if (snprintf(filename, sizeof(filename), "%s/%s",
1016                                 input_path, entry->d_name) < 0) {
1017                         ERR("Failed to format path.");
1018                         continue;
1019                 }
1020
1021                 if (stat(filename, &st)) {
1022                         PERROR("stat");
1023                         continue;
1024                 }
1025
1026                 if (S_ISDIR(st.st_mode)) {
1027                         char output_subpath[PATH_MAX];
1028                         char input_subpath[PATH_MAX];
1029
1030                         strncpy(output_subpath, output_path,
1031                                 sizeof(output_subpath));
1032                         output_subpath[sizeof(output_subpath) - 1] = '\0';
1033                         strncat(output_subpath, "/",
1034                                 sizeof(output_subpath) - strlen(output_subpath) - 1);
1035                         strncat(output_subpath, entry->d_name,
1036                                 sizeof(output_subpath) - strlen(output_subpath) - 1);
1037
1038                         ret = mkdir(output_subpath, S_IRWXU | S_IRWXG);
1039                         if (ret) {
1040                                 PERROR("mkdir");
1041                                 has_warning = 1;
1042                                 goto end;
1043                         }
1044
1045                         strncpy(input_subpath, input_path,
1046                                 sizeof(input_subpath));
1047                         input_subpath[sizeof(input_subpath) - 1] = '\0';
1048                         strncat(input_subpath, "/",
1049                                 sizeof(input_subpath) - strlen(input_subpath) - 1);
1050                         strncat(input_subpath, entry->d_name,
1051                                 sizeof(input_subpath) - strlen(input_subpath) - 1);
1052
1053                         ret = extract_trace_recursive(output_subpath,
1054                                 input_subpath);
1055                         if (ret) {
1056                                 has_warning = 1;
1057                         }
1058                 } else if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
1059                         if (!strcmp(entry->d_name, "metadata")) {
1060                                 ret = extract_one_trace(output_path,
1061                                         input_path);
1062                                 if (ret) {
1063                                         WARN("Error extracting trace '%s', continuing anyway.",
1064                                                 input_path);
1065                                         has_warning = 1;
1066                                 }
1067                         }
1068                 } else {
1069                         has_warning = 1;
1070                         goto end;
1071                 }
1072         }
1073 end:
1074         closeret = closedir(dir);
1075         if (closeret) {
1076                 PERROR("closedir");
1077         }
1078         return has_warning;
1079 }
1080
1081 static
1082 int delete_dir_recursive(const char *path)
1083 {
1084         DIR *dir;
1085         int dir_fd, ret = 0, closeret;
1086         size_t path_len;
1087         struct dirent *entry;
1088
1089         /* Open trace directory */
1090         dir = opendir(path);
1091         if (!dir) {
1092                 PERROR("Cannot open '%s' path", path);
1093                 ret = -errno;
1094                 goto end;
1095         }
1096
1097         path_len = strlen(path);
1098
1099         dir_fd = dirfd(dir);
1100         if (dir_fd < 0) {
1101                 PERROR("dirfd");
1102                 ret = -errno;
1103                 goto end;
1104         }
1105
1106         while ((entry = readdir(dir))) {
1107                 struct stat st;
1108                 size_t name_len;
1109                 char filename[PATH_MAX];
1110
1111                 if (!strcmp(entry->d_name, ".")
1112                                 || !strcmp(entry->d_name, "..")) {
1113                         continue;
1114                 }
1115
1116                 name_len = strlen(entry->d_name);
1117                 if (path_len + name_len + 2 > sizeof(filename)) {
1118                         ERR("Failed to remove file: path name too long (%s/%s)",
1119                                 path, entry->d_name);
1120                         continue;
1121                 }
1122
1123                 if (snprintf(filename, sizeof(filename), "%s/%s",
1124                                 path, entry->d_name) < 0) {
1125                         ERR("Failed to format path.");
1126                         continue;
1127                 }
1128
1129                 if (stat(filename, &st)) {
1130                         PERROR("stat");
1131                         continue;
1132                 }
1133
1134                 if (S_ISDIR(st.st_mode)) {
1135                         char *subpath = zmalloc(PATH_MAX);
1136
1137                         if (!subpath) {
1138                                 PERROR("zmalloc path");
1139                                 ret = -1;
1140                                 goto end;
1141                         }
1142                         strncpy(subpath, path, PATH_MAX);
1143                         subpath[PATH_MAX - 1] = '\0';
1144                         strncat(subpath, "/",
1145                                         PATH_MAX - strlen(subpath) - 1);
1146                         strncat(subpath, entry->d_name,
1147                                         PATH_MAX - strlen(subpath) - 1);
1148
1149                         ret = delete_dir_recursive(subpath);
1150                         free(subpath);
1151                         if (ret) {
1152                                 /* Error occured, abort traversal. */
1153                                 goto end;
1154                         }
1155                 } else if (S_ISREG(st.st_mode)) {
1156                         ret = unlinkat(dir_fd, entry->d_name, 0);
1157                         if (ret) {
1158                                 PERROR("Unlinking '%s'", entry->d_name);
1159                                 goto end;
1160                         }
1161                 } else {
1162                         ret = -EINVAL;
1163                         goto end;
1164                 }
1165         }
1166 end:
1167         if (!ret) {
1168                 ret = rmdir(path);
1169                 if (ret) {
1170                         PERROR("rmdir '%s'", path);
1171                 }
1172         }
1173         closeret = closedir(dir);
1174         if (closeret) {
1175                 PERROR("closedir");
1176         }
1177         return ret;
1178 }
1179
1180 static
1181 int view_trace(const char *viewer_path, const char *trace_path)
1182 {
1183         pid_t pid;
1184
1185         pid = fork();
1186         if (pid < 0) {
1187                 /* Error */
1188                 PERROR("fork");
1189                 return -1;
1190         } else if (pid > 0) {
1191                 /* Parent */
1192                 int status;
1193
1194                 pid = waitpid(pid, &status, 0);
1195                 if (pid < 0 || !WIFEXITED(status)) {
1196                         return -1;
1197                 }
1198         } else {
1199                 /* Child */
1200                 int ret;
1201
1202                 ret = execlp(viewer_path, viewer_path,
1203                         trace_path, (char *) NULL);
1204                 if (ret) {
1205                         PERROR("execlp");
1206                         exit(EXIT_FAILURE);
1207                 }
1208                 exit(EXIT_SUCCESS);     /* Never reached */
1209         }
1210         return 0;
1211 }
1212
1213 /*
1214  *  main
1215  */
1216 int main(int argc, char *argv[])
1217 {
1218         int ret, has_warning = 0;
1219         const char *output_path = NULL;
1220         char tmppath[] = "/tmp/lttng-crash-XXXXXX";
1221
1222         progname = argv[0] ? argv[0] : "lttng-crash";
1223
1224         ret = parse_args(argc, argv);
1225         if (ret > 0) {
1226                 exit(EXIT_SUCCESS);
1227         } else if (ret < 0) {
1228                 exit(EXIT_FAILURE);
1229         }
1230
1231         if (opt_output_path) {
1232                 output_path = opt_output_path;
1233                 ret = mkdir(output_path, S_IRWXU | S_IRWXG);
1234                 if (ret) {
1235                         PERROR("mkdir");
1236                         exit(EXIT_FAILURE);
1237                 }
1238         } else {
1239                 output_path = mkdtemp(tmppath);
1240                 if (!output_path) {
1241                         PERROR("mkdtemp");
1242                         exit(EXIT_FAILURE);
1243                 }
1244         }
1245
1246         ret = extract_trace_recursive(output_path, input_path);
1247         if (ret < 0) {
1248                 exit(EXIT_FAILURE);
1249         } else if (ret > 0) {
1250                 has_warning = 1;
1251         }
1252         if (!opt_output_path) {
1253                 /* View trace */
1254                 ret = view_trace(opt_viewer_path, output_path);
1255                 if (ret)
1256                         has_warning = 1;
1257
1258                 /* unlink temporary trace */
1259                 ret = delete_dir_recursive(output_path);
1260                 if (ret) {
1261                         has_warning = 1;
1262                 }
1263         }
1264         if (has_warning)
1265                 exit(EXIT_FAILURE);
1266         exit(EXIT_SUCCESS);
1267 }