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