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

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