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