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