lib/iterator.c

   1 /*
   2  * iterator.c
   3  *
   4  * Babeltrace Library
   5  *
   6  * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
   7  *
   8  * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  */
  20
  21 #include <stdlib.h>
  22 #include <babeltrace/babeltrace.h>
  23 #include <babeltrace/context.h>
  24 #include <babeltrace/context-internal.h>
  25 #include <babeltrace/iterator-internal.h>
  26 #include <babeltrace/iterator.h>
  27 #include <babeltrace/prio_heap.h>
  28 #include <babeltrace/ctf/metadata.h>
  29 #include <babeltrace/ctf/events.h>
  30 #include <inttypes.h>
  31
  32 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
  33                 const struct bt_iter_pos *begin_pos,
  34                 unsigned long stream_id);
  35
  36 struct stream_saved_pos {
  37         /*
  38          * Use file_stream pointer to check if the trace collection we
  39          * restore to match the one we saved from, for each stream.
  40          */
  41         struct ctf_file_stream *file_stream;
  42         size_t cur_index;       /* current index in packet index */
  43         ssize_t offset;         /* offset from base, in bits. EOF for end of file. */
  44         uint64_t current_real_timestamp;
  45         uint64_t current_cycles_timestamp;
  46 };
  47
  48 struct bt_saved_pos {
  49         struct trace_collection *tc;
  50         GArray *stream_saved_pos;       /* Contains struct stream_saved_pos */
  51 };
  52
  53 static int stream_read_event(struct ctf_file_stream *sin)
  54 {
  55         int ret;
  56
  57         ret = sin->pos.parent.event_cb(&sin->pos.parent, &sin->parent);
  58         if (ret == EOF)
  59                 return EOF;
  60         else if (ret) {
  61                 fprintf(stderr, "[error] Reading event failed.\n");
  62                 return ret;
  63         }
  64         return 0;
  65 }
  66
  67 /*
  68  * returns true if a < b, false otherwise.
  69  */
  70 int stream_compare(void *a, void *b)
  71 {
  72         struct ctf_file_stream *s_a = a, *s_b = b;
  73
  74         if (s_a->parent.real_timestamp < s_b->parent.real_timestamp)
  75                 return 1;
  76         else
  77                 return 0;
  78 }
  79
  80 void bt_iter_free_pos(struct bt_iter_pos *iter_pos)
  81 {
  82         if (!iter_pos)
  83                 return;
  84
  85         if (iter_pos->type == BT_SEEK_RESTORE && iter_pos->u.restore) {
  86                 if (iter_pos->u.restore->stream_saved_pos) {
  87                         g_array_free(
  88                                 iter_pos->u.restore->stream_saved_pos,
  89                                 TRUE);
  90                 }
  91                 g_free(iter_pos->u.restore);
  92         }
  93         g_free(iter_pos);
  94 }
  95
  96 /*
  97  * seek_file_stream_by_timestamp
  98  *
  99  * Browse a filestream by index, if an index contains the timestamp passed in
 100  * argument, seek inside the corresponding packet it until we find the event we
 101  * are looking for (either the exact timestamp or the event just after the
 102  * timestamp).
 103  *
 104  * Return 0 if the seek succeded, EOF if we didn't find any packet
 105  * containing the timestamp, or a positive integer for error.
 106  */
 107 static int seek_file_stream_by_timestamp(struct ctf_file_stream *cfs,
 108                 uint64_t timestamp)
 109 {
 110         struct ctf_stream_pos *stream_pos;
 111         struct packet_index *index;
 112         int i, ret;
 113
 114         stream_pos = &cfs->pos;
 115         for (i = 0; i < stream_pos->packet_real_index->len; i++) {
 116                 index = &g_array_index(stream_pos->packet_real_index,
 117                                 struct packet_index, i);
 118                 if (index->timestamp_end < timestamp)
 119                         continue;
 120
 121                 stream_pos->packet_seek(&stream_pos->parent, i, SEEK_SET);
 122                 do {
 123                         ret = stream_read_event(cfs);
 124                 } while (cfs->parent.real_timestamp < timestamp && ret == 0);
 125
 126                 /* Can return either EOF, 0, or error (> 0). */
 127                 return ret;
 128         }
 129         /*
 130          * Cannot find the timestamp within the stream packets, return
 131          * EOF.
 132          */
 133         return EOF;
 134 }
 135
 136 /*
 137  * seek_ctf_trace_by_timestamp : for each file stream, seek to the event with
 138  * the corresponding timestamp
 139  *
 140  * Return 0 on success.
 141  * If the timestamp is not part of any file stream, return EOF to inform the
 142  * user the timestamp is out of the scope.
 143  * On other errors, return positive value.
 144  */
 145 static int seek_ctf_trace_by_timestamp(struct ctf_trace *tin,
 146                 uint64_t timestamp, struct ptr_heap *stream_heap)
 147 {
 148         int i, j, ret;
 149         int found = 0;
 150
 151         /* for each stream_class */
 152         for (i = 0; i < tin->streams->len; i++) {
 153                 struct ctf_stream_declaration *stream_class;
 154
 155                 stream_class = g_ptr_array_index(tin->streams, i);
 156                 if (!stream_class)
 157                         continue;
 158                 /* for each file_stream */
 159                 for (j = 0; j < stream_class->streams->len; j++) {
 160                         struct ctf_stream_definition *stream;
 161                         struct ctf_file_stream *cfs;
 162
 163                         stream = g_ptr_array_index(stream_class->streams, j);
 164                         if (!stream)
 165                                 continue;
 166                         cfs = container_of(stream, struct ctf_file_stream,
 167                                         parent);
 168                         ret = seek_file_stream_by_timestamp(cfs, timestamp);
 169                         if (ret == 0) {
 170                                 /* Add to heap */
 171                                 ret = heap_insert(stream_heap, cfs);
 172                                 if (ret) {
 173                                         /* Return positive error. */
 174                                         return -ret;
 175                                 }
 176                                 found = 1;
 177                         } else if (ret > 0) {
 178                                 /*
 179                                  * Error in seek (not EOF), failure.
 180                                  */
 181                                 return ret;
 182                         }
 183                         /* on EOF just do not put stream into heap. */
 184                 }
 185         }
 186
 187         return found ? 0 : EOF;
 188 }
 189
 190 int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *iter_pos)
 191 {
 192         struct trace_collection *tc;
 193         int i, ret;
 194
 195         switch (iter_pos->type) {
 196         case BT_SEEK_RESTORE:
 197                 if (!iter_pos->u.restore)
 198                         return -EINVAL;
 199
 200                 heap_free(iter->stream_heap);
 201                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 202                 if (ret < 0)
 203                         goto error_heap_init;
 204
 205                 for (i = 0; i < iter_pos->u.restore->stream_saved_pos->len;
 206                                 i++) {
 207                         struct stream_saved_pos *saved_pos;
 208                         struct ctf_stream_pos *stream_pos;
 209                         struct ctf_stream_definition *stream;
 210
 211                         saved_pos = &g_array_index(
 212                                         iter_pos->u.restore->stream_saved_pos,
 213                                         struct stream_saved_pos, i);
 214                         stream = &saved_pos->file_stream->parent;
 215                         stream_pos = &saved_pos->file_stream->pos;
 216
 217                         stream_pos->packet_seek(&stream_pos->parent,
 218                                         saved_pos->cur_index, SEEK_SET);
 219
 220                         /*
 221                          * the timestamp needs to be restored after
 222                          * packet_seek, because this function resets
 223                          * the timestamp to the beginning of the packet
 224                          */
 225                         stream->real_timestamp = saved_pos->current_real_timestamp;
 226                         stream->cycles_timestamp = saved_pos->current_cycles_timestamp;
 227                         stream_pos->offset = saved_pos->offset;
 228                         stream_pos->last_offset = LAST_OFFSET_POISON;
 229
 230                         stream->prev_real_timestamp = 0;
 231                         stream->prev_real_timestamp_end = 0;
 232                         stream->prev_cycles_timestamp = 0;
 233                         stream->prev_cycles_timestamp_end = 0;
 234
 235                         printf_debug("restored to cur_index = %zd and "
 236                                 "offset = %zd, timestamp = %" PRIu64 "\n",
 237                                 stream_pos->cur_index,
 238                                 stream_pos->offset, stream->real_timestamp);
 239
 240                         stream_read_event(saved_pos->file_stream);
 241
 242                         /* Add to heap */
 243                         ret = heap_insert(iter->stream_heap,
 244                                         saved_pos->file_stream);
 245                         if (ret)
 246                                 goto error;
 247                 }
 248                 return 0;
 249         case BT_SEEK_TIME:
 250                 tc = iter->ctx->tc;
 251
 252                 heap_free(iter->stream_heap);
 253                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 254                 if (ret < 0)
 255                         goto error_heap_init;
 256
 257                 /* for each trace in the trace_collection */
 258                 for (i = 0; i < tc->array->len; i++) {
 259                         struct ctf_trace *tin;
 260                         struct trace_descriptor *td_read;
 261
 262                         td_read = g_ptr_array_index(tc->array, i);
 263                         if (!td_read)
 264                                 continue;
 265                         tin = container_of(td_read, struct ctf_trace, parent);
 266
 267                         ret = seek_ctf_trace_by_timestamp(tin,
 268                                         iter_pos->u.seek_time,
 269                                         iter->stream_heap);
 270                         /*
 271                          * Positive errors are failure. Negative value
 272                          * is EOF (for which we continue with other
 273                          * traces). 0 is success. Note: on EOF, it just
 274                          * means that no stream has been added to the
 275                          * iterator for that trace, which is fine.
 276                          */
 277                         if (ret != 0 && ret != EOF)
 278                                 goto error;
 279                 }
 280                 return 0;
 281         case BT_SEEK_BEGIN:
 282                 tc = iter->ctx->tc;
 283                 heap_free(iter->stream_heap);
 284                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 285                 if (ret < 0)
 286                         goto error_heap_init;
 287
 288                 for (i = 0; i < tc->array->len; i++) {
 289                         struct ctf_trace *tin;
 290                         struct trace_descriptor *td_read;
 291                         int stream_id;
 292
 293                         td_read = g_ptr_array_index(tc->array, i);
 294                         if (!td_read)
 295                                 continue;
 296                         tin = container_of(td_read, struct ctf_trace, parent);
 297
 298                         /* Populate heap with each stream */
 299                         for (stream_id = 0; stream_id < tin->streams->len;
 300                                         stream_id++) {
 301                                 struct ctf_stream_declaration *stream;
 302                                 int filenr;
 303
 304                                 stream = g_ptr_array_index(tin->streams,
 305                                                 stream_id);
 306                                 if (!stream)
 307                                         continue;
 308                                 for (filenr = 0; filenr < stream->streams->len;
 309                                                 filenr++) {
 310                                         struct ctf_file_stream *file_stream;
 311                                         file_stream = g_ptr_array_index(
 312                                                         stream->streams,
 313                                                         filenr);
 314                                         if (!file_stream)
 315                                                 continue;
 316                                         ret = babeltrace_filestream_seek(
 317                                                         file_stream, iter_pos,
 318                                                         stream_id);
 319                                         if (ret != 0 && ret != EOF) {
 320                                                 goto error;
 321                                         }
 322                                         ret = heap_insert(iter->stream_heap, file_stream);
 323                                         if (ret)
 324                                                 goto error;
 325                                 }
 326                         }
 327                 }
 328                 break;
 329         default:
 330                 /* not implemented */
 331                 return -EINVAL;
 332         }
 333
 334         return 0;
 335
 336 error:
 337         heap_free(iter->stream_heap);
 338 error_heap_init:
 339         if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
 340                 heap_free(iter->stream_heap);
 341                 g_free(iter->stream_heap);
 342                 iter->stream_heap = NULL;
 343                 ret = -ENOMEM;
 344         }
 345
 346         return ret;
 347 }
 348
 349 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
 350 {
 351         struct bt_iter_pos *pos;
 352         struct trace_collection *tc = iter->ctx->tc;
 353         struct ctf_file_stream *file_stream = NULL, *removed;
 354         struct ptr_heap iter_heap_copy;
 355         int ret;
 356
 357         pos = g_new0(struct bt_iter_pos, 1);
 358         pos->type = BT_SEEK_RESTORE;
 359         pos->u.restore = g_new0(struct bt_saved_pos, 1);
 360         pos->u.restore->tc = tc;
 361         pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
 362                         sizeof(struct stream_saved_pos));
 363         if (!pos->u.restore->stream_saved_pos)
 364                 goto error;
 365
 366         ret = heap_copy(&iter_heap_copy, iter->stream_heap);
 367         if (ret < 0)
 368                 goto error_heap;
 369
 370         /* iterate over each stream in the heap */
 371         file_stream = heap_maximum(&iter_heap_copy);
 372         while (file_stream != NULL) {
 373                 struct stream_saved_pos saved_pos;
 374
 375                 assert(file_stream->pos.last_offset != LAST_OFFSET_POISON);
 376                 saved_pos.offset = file_stream->pos.last_offset;
 377                 saved_pos.file_stream = file_stream;
 378                 saved_pos.cur_index = file_stream->pos.cur_index;
 379
 380                 saved_pos.current_real_timestamp = file_stream->parent.real_timestamp;
 381                 saved_pos.current_cycles_timestamp = file_stream->parent.cycles_timestamp;
 382
 383                 g_array_append_val(
 384                                 pos->u.restore->stream_saved_pos,
 385                                 saved_pos);
 386
 387                 printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
 388                                 "offset : %zd, "
 389                                 "timestamp = %" PRIu64 "\n",
 390                                 file_stream->parent.stream_id,
 391                                 saved_pos.cur_index, saved_pos.offset,
 392                                 saved_pos.current_real_timestamp);
 393
 394                 /* remove the stream from the heap copy */
 395                 removed = heap_remove(&iter_heap_copy);
 396                 assert(removed == file_stream);
 397
 398                 file_stream = heap_maximum(&iter_heap_copy);
 399         }
 400         heap_free(&iter_heap_copy);
 401         return pos;
 402
 403 error_heap:
 404         g_array_free(pos->u.restore->stream_saved_pos, TRUE);
 405 error:
 406         g_free(pos);
 407         return NULL;
 408 }
 409
 410 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 411                 uint64_t timestamp)
 412 {
 413         struct bt_iter_pos *pos;
 414
 415         pos = g_new0(struct bt_iter_pos, 1);
 416         pos->type = BT_SEEK_TIME;
 417         pos->u.seek_time = timestamp;
 418         return pos;
 419 }
 420
 421 /*
 422  * babeltrace_filestream_seek: seek a filestream to given position.
 423  *
 424  * The stream_id parameter is only useful for BT_SEEK_RESTORE.
 425  */
 426 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
 427                 const struct bt_iter_pos *begin_pos,
 428                 unsigned long stream_id)
 429 {
 430         int ret = 0;
 431
 432         switch (begin_pos->type) {
 433         case BT_SEEK_CUR:
 434                 /*
 435                  * just insert into the heap we should already know
 436                  * the timestamps
 437                  */
 438                 break;
 439         case BT_SEEK_BEGIN:
 440                 file_stream->pos.packet_seek(&file_stream->pos.parent,
 441                                 0, SEEK_SET);
 442                 ret = stream_read_event(file_stream);
 443                 break;
 444         case BT_SEEK_TIME:
 445         case BT_SEEK_RESTORE:
 446         case BT_SEEK_END:
 447         default:
 448                 assert(0); /* Not yet defined */
 449         }
 450
 451         return ret;
 452 }
 453
 454 int bt_iter_init(struct bt_iter *iter,
 455                 struct bt_context *ctx,
 456                 const struct bt_iter_pos *begin_pos,
 457                 const struct bt_iter_pos *end_pos)
 458 {
 459         int i, stream_id;
 460         int ret = 0;
 461
 462         if (ctx->current_iterator) {
 463                 ret = -1;
 464                 goto error_ctx;
 465         }
 466
 467         iter->stream_heap = g_new(struct ptr_heap, 1);
 468         iter->end_pos = end_pos;
 469         bt_context_get(ctx);
 470         iter->ctx = ctx;
 471
 472         ret = heap_init(iter->stream_heap, 0, stream_compare);
 473         if (ret < 0)
 474                 goto error_heap_init;
 475
 476         for (i = 0; i < ctx->tc->array->len; i++) {
 477                 struct ctf_trace *tin;
 478                 struct trace_descriptor *td_read;
 479
 480                 td_read = g_ptr_array_index(ctx->tc->array, i);
 481                 if (!td_read)
 482                         continue;
 483                 tin = container_of(td_read, struct ctf_trace, parent);
 484
 485                 /* Populate heap with each stream */
 486                 for (stream_id = 0; stream_id < tin->streams->len;
 487                                 stream_id++) {
 488                         struct ctf_stream_declaration *stream;
 489                         int filenr;
 490
 491                         stream = g_ptr_array_index(tin->streams, stream_id);
 492                         if (!stream)
 493                                 continue;
 494                         for (filenr = 0; filenr < stream->streams->len;
 495                                         filenr++) {
 496                                 struct ctf_file_stream *file_stream;
 497
 498                                 file_stream = g_ptr_array_index(stream->streams,
 499                                                 filenr);
 500                                 if (!file_stream)
 501                                         continue;
 502                                 if (begin_pos) {
 503                                         ret = babeltrace_filestream_seek(
 504                                                         file_stream,
 505                                                         begin_pos,
 506                                                         stream_id);
 507                                 } else {
 508                                         struct bt_iter_pos pos;
 509                                         pos.type = BT_SEEK_BEGIN;
 510                                         ret = babeltrace_filestream_seek(
 511                                                         file_stream, &pos,
 512                                                         stream_id);
 513                                 }
 514                                 if (ret == EOF) {
 515                                         ret = 0;
 516                                         continue;
 517                                 } else if (ret) {
 518                                         goto error;
 519                                 }
 520                                 /* Add to heap */
 521                                 ret = heap_insert(iter->stream_heap, file_stream);
 522                                 if (ret)
 523                                         goto error;
 524                         }
 525                 }
 526         }
 527
 528         ctx->current_iterator = iter;
 529         return 0;
 530
 531 error:
 532         heap_free(iter->stream_heap);
 533 error_heap_init:
 534         g_free(iter->stream_heap);
 535         iter->stream_heap = NULL;
 536 error_ctx:
 537         return ret;
 538 }
 539
 540 struct bt_iter *bt_iter_create(struct bt_context *ctx,
 541                 const struct bt_iter_pos *begin_pos,
 542                 const struct bt_iter_pos *end_pos)
 543 {
 544         struct bt_iter *iter;
 545         int ret;
 546
 547         iter = g_new0(struct bt_iter, 1);
 548         ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
 549         if (ret) {
 550                 g_free(iter);
 551                 return NULL;
 552         }
 553         return iter;
 554 }
 555
 556 void bt_iter_fini(struct bt_iter *iter)
 557 {
 558         if (iter->stream_heap) {
 559                 heap_free(iter->stream_heap);
 560                 g_free(iter->stream_heap);
 561         }
 562         iter->ctx->current_iterator = NULL;
 563         bt_context_put(iter->ctx);
 564 }
 565
 566 void bt_iter_destroy(struct bt_iter *iter)
 567 {
 568         bt_iter_fini(iter);
 569         g_free(iter);
 570 }
 571
 572 int bt_iter_next(struct bt_iter *iter)
 573 {
 574         struct ctf_file_stream *file_stream, *removed;
 575         int ret;
 576
 577         file_stream = heap_maximum(iter->stream_heap);
 578         if (!file_stream) {
 579                 /* end of file for all streams */
 580                 ret = 0;
 581                 goto end;
 582         }
 583
 584         ret = stream_read_event(file_stream);
 585         if (ret == EOF) {
 586                 removed = heap_remove(iter->stream_heap);
 587                 assert(removed == file_stream);
 588                 ret = 0;
 589                 goto end;
 590         } else if (ret) {
 591                 goto end;
 592         }
 593         /* Reinsert the file stream into the heap, and rebalance. */
 594         removed = heap_replace_max(iter->stream_heap, file_stream);
 595         assert(removed == file_stream);
 596
 597 end:
 598         return ret;
 599 }