libust/tracectl.c

   1 /* Copyright (C) 2009  Pierre-Marc Fournier
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  16  */
  17
  18 /* This file contains the implementation of the UST listener thread, which
  19  * receives trace control commands. It also coordinates the initialization of
  20  * libust.
  21  */
  22
  23 #define _GNU_SOURCE
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <stdint.h>
  27 #include <pthread.h>
  28 #include <signal.h>
  29 #include <sys/epoll.h>
  30 #include <sys/time.h>
  31 #include <sys/types.h>
  32 #include <sys/socket.h>
  33 #include <fcntl.h>
  34 #include <poll.h>
  35 #include <regex.h>
  36 #include <urcu/uatomic_arch.h>
  37 #include <urcu/list.h>
  38
  39 #include <ust/marker.h>
  40 #include <ust/tracepoint.h>
  41 #include <ust/tracectl.h>
  42 #include "tracer.h"
  43 #include "usterr.h"
  44 #include "ustcomm.h"
  45 #include "buffers.h"
  46 #include "marker-control.h"
  47
  48 #define USTSIGNAL SIGIO
  49
  50 #define MAX_MSG_SIZE (100)
  51 #define MSG_NOTIF 1
  52 #define MSG_REGISTER_NOTIF 2
  53
  54 /* This should only be accessed by the constructor, before the creation
  55  * of the listener, and then only by the listener.
  56  */
  57 s64 pidunique = -1LL;
  58
  59 static int epoll_fd;
  60 static struct ustcomm_sock *listen_sock;
  61
  62 extern struct chan_info_struct chan_infos[];
  63
  64 static struct list_head open_buffers_list = LIST_HEAD_INIT(open_buffers_list);
  65
  66 static struct list_head ust_socks = LIST_HEAD_INIT(ust_socks);
  67
  68 /* volatile because shared between the listener and the main thread */
  69 int buffers_to_export = 0;
  70
  71 static long long make_pidunique(void)
  72 {
  73         s64 retval;
  74         struct timeval tv;
  75
  76         gettimeofday(&tv, NULL);
  77
  78         retval = tv.tv_sec;
  79         retval <<= 32;
  80         retval |= tv.tv_usec;
  81
  82         return retval;
  83 }
  84
  85 static void print_markers(FILE *fp)
  86 {
  87         struct marker_iter iter;
  88
  89         lock_markers();
  90         marker_iter_reset(&iter);
  91         marker_iter_start(&iter);
  92
  93         while (iter.marker) {
  94                 fprintf(fp, "marker: %s/%s %d \"%s\" %p\n",
  95                         iter.marker->channel,
  96                         iter.marker->name,
  97                         (int)imv_read(iter.marker->state),
  98                         iter.marker->format,
  99                         iter.marker->location);
 100                 marker_iter_next(&iter);
 101         }
 102         unlock_markers();
 103 }
 104
 105 static void print_trace_events(FILE *fp)
 106 {
 107         struct trace_event_iter iter;
 108
 109         lock_trace_events();
 110         trace_event_iter_reset(&iter);
 111         trace_event_iter_start(&iter);
 112
 113         while (iter.trace_event) {
 114                 fprintf(fp, "trace_event: %s\n", iter.trace_event->name);
 115                 trace_event_iter_next(&iter);
 116         }
 117         unlock_trace_events();
 118 }
 119
 120 /* Ask the daemon to collect a trace called trace_name and being
 121  * produced by this pid.
 122  *
 123  * The trace must be at least allocated. (It can also be started.)
 124  * This is because _ltt_trace_find is used.
 125  */
 126
 127 static void inform_consumer_daemon(const char *trace_name)
 128 {
 129         int i,j;
 130         struct ust_trace *trace;
 131         pid_t pid = getpid();
 132         int result;
 133
 134         ltt_lock_traces();
 135
 136         trace = _ltt_trace_find(trace_name);
 137         if (trace == NULL) {
 138                 WARN("inform_consumer_daemon: could not find trace \"%s\"; it is probably already destroyed", trace_name);
 139                 goto finish;
 140         }
 141
 142         for (i=0; i < trace->nr_channels; i++) {
 143                 if (trace->channels[i].request_collection) {
 144                         /* iterate on all cpus */
 145                         for (j=0; j<trace->channels[i].n_cpus; j++) {
 146                                 char *buf;
 147                                 if (asprintf(&buf, "%s_%d", trace->channels[i].channel_name, j) < 0) {
 148                                        ERR("inform_consumer_daemon : asprintf failed (%s_%d)",
 149                                            trace->channels[i].channel_name, j);
 150                                        goto finish;
 151                                 }
 152                                 result = ustcomm_request_consumer(pid, buf);
 153                                 if (result == -1) {
 154                                         WARN("Failed to request collection for channel %s. Is the daemon available?",
 155                                              trace->channels[i].channel_name);
 156                                         /* continue even if fail */
 157                                 }
 158                                 free(buf);
 159                                 STORE_SHARED(buffers_to_export, LOAD_SHARED(buffers_to_export)+1);
 160                         }
 161                 }
 162         }
 163
 164         finish:
 165         ltt_unlock_traces();
 166 }
 167
 168 void seperate_channel_cpu(const char *channel_and_cpu, char **channel, int *cpu)
 169 {
 170         const char *sep;
 171
 172         sep = rindex(channel_and_cpu, '_');
 173         if (sep == NULL) {
 174                 *cpu = -1;
 175                 sep = channel_and_cpu + strlen(channel_and_cpu);
 176         } else {
 177                 *cpu = atoi(sep+1);
 178         }
 179
 180         if (asprintf(channel, "%.*s", (int)(sep-channel_and_cpu), channel_and_cpu) < 0) {
 181                 ERR("seperate_channel_cpu : asprintf failed (%.*s)",
 182                     (int)(sep-channel_and_cpu), channel_and_cpu);
 183                 return;
 184         }
 185 }
 186
 187 static int do_cmd_get_shmid(const char *recvbuf, int sock)
 188 {
 189         int retval = 0;
 190         struct ust_trace *trace;
 191         char trace_name[] = "auto";
 192         int i;
 193         char *channel_and_cpu;
 194         int found = 0;
 195         int result;
 196         char *ch_name;
 197         int ch_cpu;
 198
 199         DBG("get_shmid");
 200
 201         channel_and_cpu = nth_token(recvbuf, 1);
 202         if (channel_and_cpu == NULL) {
 203                 ERR("cannot parse channel");
 204                 retval = -1;
 205                 goto end;
 206         }
 207
 208         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 209         if (ch_cpu == -1) {
 210                 ERR("problem parsing channel name");
 211                 retval = -1;
 212                 goto free_short_chan_name;
 213         }
 214
 215         ltt_lock_traces();
 216         trace = _ltt_trace_find(trace_name);
 217         ltt_unlock_traces();
 218
 219         if (trace == NULL) {
 220                 ERR("cannot find trace!");
 221                 retval = -1;
 222                 goto free_short_chan_name;
 223         }
 224
 225         for (i=0; i<trace->nr_channels; i++) {
 226                 struct ust_channel *channel = &trace->channels[i];
 227                 struct ust_buffer *buf = channel->buf[ch_cpu];
 228
 229                 if (!strcmp(trace->channels[i].channel_name, ch_name)) {
 230                         char *reply;
 231
 232 //                      DBG("the shmid for the requested channel is %d", buf->shmid);
 233 //                      DBG("the shmid for its buffer structure is %d", channel->buf_struct_shmids);
 234                         if (asprintf(&reply, "%d %d", buf->shmid, channel->buf_struct_shmids[ch_cpu]) < 0) {
 235                                 ERR("do_cmd_get_shmid : asprintf failed (%d %d)",
 236                                     buf->shmid, channel->buf_struct_shmids[ch_cpu]);
 237                                 retval = -1;
 238                                 goto free_short_chan_name;
 239                         }
 240
 241                         result = ustcomm_send_reply(reply, sock);
 242                         if (result) {
 243                                 ERR("ustcomm_send_reply failed");
 244                                 free(reply);
 245                                 retval = -1;
 246                                 goto free_short_chan_name;
 247                         }
 248
 249                         free(reply);
 250
 251                         found = 1;
 252                         break;
 253                 }
 254         }
 255
 256         if (!found) {
 257                 ERR("channel not found (%s)", channel_and_cpu);
 258         }
 259
 260         free_short_chan_name:
 261         free(ch_name);
 262
 263         end:
 264         return retval;
 265 }
 266
 267 static int do_cmd_get_n_subbufs(const char *recvbuf, int sock)
 268 {
 269         int retval = 0;
 270         struct ust_trace *trace;
 271         char trace_name[] = "auto";
 272         int i;
 273         char *channel_and_cpu;
 274         int found = 0;
 275         int result;
 276         char *ch_name;
 277         int ch_cpu;
 278
 279         DBG("get_n_subbufs");
 280
 281         channel_and_cpu = nth_token(recvbuf, 1);
 282         if (channel_and_cpu == NULL) {
 283                 ERR("cannot parse channel");
 284                 retval = -1;
 285                 goto end;
 286         }
 287
 288         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 289         if (ch_cpu == -1) {
 290                 ERR("problem parsing channel name");
 291                 retval = -1;
 292                 goto free_short_chan_name;
 293         }
 294
 295         ltt_lock_traces();
 296         trace = _ltt_trace_find(trace_name);
 297         ltt_unlock_traces();
 298
 299         if (trace == NULL) {
 300                 ERR("cannot find trace!");
 301                 retval = -1;
 302                 goto free_short_chan_name;
 303         }
 304
 305         for (i=0; i<trace->nr_channels; i++) {
 306                 struct ust_channel *channel = &trace->channels[i];
 307
 308                 if (!strcmp(trace->channels[i].channel_name, ch_name)) {
 309                         char *reply;
 310
 311                         DBG("the n_subbufs for the requested channel is %d", channel->subbuf_cnt);
 312                         if (asprintf(&reply, "%d", channel->subbuf_cnt) < 0) {
 313                                 ERR("do_cmd_get_n_subbufs : asprintf failed (%d)",
 314                                     channel->subbuf_cnt);
 315                                 retval = -1;
 316                                 goto free_short_chan_name;
 317                         }
 318
 319                         result = ustcomm_send_reply(reply, sock);
 320                         if (result) {
 321                                 ERR("ustcomm_send_reply failed");
 322                                 free(reply);
 323                                 retval = -1;
 324                                 goto free_short_chan_name;
 325                         }
 326
 327                         free(reply);
 328                         found = 1;
 329                         break;
 330                 }
 331         }
 332         if (found == 0) {
 333                 ERR("unable to find channel");
 334         }
 335
 336         free_short_chan_name:
 337         free(ch_name);
 338
 339         end:
 340         return retval;
 341 }
 342
 343 static int do_cmd_get_subbuf_size(const char *recvbuf, int sock)
 344 {
 345         int retval = 0;
 346         struct ust_trace *trace;
 347         char trace_name[] = "auto";
 348         int i;
 349         char *channel_and_cpu;
 350         int found = 0;
 351         int result;
 352         char *ch_name;
 353         int ch_cpu;
 354
 355         DBG("get_subbuf_size");
 356
 357         channel_and_cpu = nth_token(recvbuf, 1);
 358         if (channel_and_cpu == NULL) {
 359                 ERR("cannot parse channel");
 360                 retval = -1;
 361                 goto end;
 362         }
 363
 364         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 365         if (ch_cpu == -1) {
 366                 ERR("problem parsing channel name");
 367                 retval = -1;
 368                 goto free_short_chan_name;
 369         }
 370
 371         ltt_lock_traces();
 372         trace = _ltt_trace_find(trace_name);
 373         ltt_unlock_traces();
 374
 375         if (trace == NULL) {
 376                 ERR("cannot find trace!");
 377                 retval = -1;
 378                 goto free_short_chan_name;
 379         }
 380
 381         for (i=0; i<trace->nr_channels; i++) {
 382                 struct ust_channel *channel = &trace->channels[i];
 383
 384                 if (!strcmp(trace->channels[i].channel_name, ch_name)) {
 385                         char *reply;
 386
 387                         DBG("the subbuf_size for the requested channel is %zd", channel->subbuf_size);
 388                         if (asprintf(&reply, "%zd", channel->subbuf_size) < 0) {
 389                                 ERR("do_cmd_get_subbuf_size : asprintf failed (%zd)",
 390                                     channel->subbuf_size);
 391                                 retval = -1;
 392                                 goto free_short_chan_name;
 393                         }
 394
 395                         result = ustcomm_send_reply(reply, sock);
 396                         if (result) {
 397                                 ERR("ustcomm_send_reply failed");
 398                                 free(reply);
 399                                 retval = -1;
 400                                 goto free_short_chan_name;
 401                         }
 402
 403                         free(reply);
 404                         found = 1;
 405                         break;
 406                 }
 407         }
 408         if (found == 0) {
 409                 ERR("unable to find channel");
 410         }
 411
 412         free_short_chan_name:
 413         free(ch_name);
 414
 415         end:
 416         return retval;
 417 }
 418
 419 /* Return the power of two which is equal or higher to v */
 420
 421 static unsigned int pow2_higher_or_eq(unsigned int v)
 422 {
 423         int hb = fls(v);
 424         int retval = 1<<(hb-1);
 425
 426         if (v-retval == 0)
 427                 return retval;
 428         else
 429                 return retval<<1;
 430 }
 431
 432 static int do_cmd_set_subbuf_size(const char *recvbuf, int sock)
 433 {
 434         char *channel_slash_size;
 435         char *ch_name = NULL;
 436         unsigned int size, power;
 437         int retval = 0;
 438         struct ust_trace *trace;
 439         char trace_name[] = "auto";
 440         int i;
 441         int found = 0;
 442
 443         DBG("set_subbuf_size");
 444
 445         channel_slash_size = nth_token(recvbuf, 1);
 446         sscanf(channel_slash_size, "%a[^/]/%u", &ch_name, &size);
 447
 448         if (ch_name == NULL) {
 449                 ERR("cannot parse channel");
 450                 retval = -1;
 451                 goto end;
 452         }
 453
 454         power = pow2_higher_or_eq(size);
 455         power = max_t(unsigned int, 2u, power);
 456         if (power != size)
 457                 WARN("using the next power of two for buffer size = %u\n", power);
 458
 459         ltt_lock_traces();
 460         trace = _ltt_trace_find_setup(trace_name);
 461         if (trace == NULL) {
 462                 ERR("cannot find trace!");
 463                 retval = -1;
 464                 goto end;
 465         }
 466
 467         for (i = 0; i < trace->nr_channels; i++) {
 468                 struct ust_channel *channel = &trace->channels[i];
 469
 470                 if (!strcmp(trace->channels[i].channel_name, ch_name)) {
 471
 472                         channel->subbuf_size = power;
 473                         DBG("the set_subbuf_size for the requested channel is %zd", channel->subbuf_size);
 474
 475                         found = 1;
 476                         break;
 477                 }
 478         }
 479         if (found == 0) {
 480                 ERR("unable to find channel");
 481         }
 482
 483         end:
 484         ltt_unlock_traces();
 485         free(ch_name);
 486         return retval;
 487 }
 488
 489 static int do_cmd_set_subbuf_num(const char *recvbuf, int sock)
 490 {
 491         char *channel_slash_num;
 492         char *ch_name = NULL;
 493         unsigned int num;
 494         int retval = 0;
 495         struct ust_trace *trace;
 496         char trace_name[] = "auto";
 497         int i;
 498         int found = 0;
 499
 500         DBG("set_subbuf_num");
 501
 502         channel_slash_num = nth_token(recvbuf, 1);
 503         sscanf(channel_slash_num, "%a[^/]/%u", &ch_name, &num);
 504
 505         if (ch_name == NULL) {
 506                 ERR("cannot parse channel");
 507                 retval = -1;
 508                 goto end;
 509         }
 510         if (num < 2) {
 511                 ERR("subbuffer count should be greater than 2");
 512                 retval = -1;
 513                 goto end;
 514         }
 515
 516         ltt_lock_traces();
 517         trace = _ltt_trace_find_setup(trace_name);
 518         if (trace == NULL) {
 519                 ERR("cannot find trace!");
 520                 retval = -1;
 521                 goto end;
 522         }
 523
 524         for (i = 0; i < trace->nr_channels; i++) {
 525                 struct ust_channel *channel = &trace->channels[i];
 526
 527                 if (!strcmp(trace->channels[i].channel_name, ch_name)) {
 528
 529                         channel->subbuf_cnt = num;
 530                         DBG("the set_subbuf_cnt for the requested channel is %zd", channel->subbuf_cnt);
 531
 532                         found = 1;
 533                         break;
 534                 }
 535         }
 536         if (found == 0) {
 537                 ERR("unable to find channel");
 538         }
 539
 540         end:
 541         ltt_unlock_traces();
 542         free(ch_name);
 543         return retval;
 544 }
 545
 546 static int do_cmd_get_subbuffer(const char *recvbuf, int sock)
 547 {
 548         int retval = 0, found = 0;;
 549         int i, ch_cpu, result;
 550         long consumed_old = 0;
 551         struct ust_trace *trace;
 552         char trace_name[] = "auto";
 553         char *channel_and_cpu;
 554         char *ch_name;
 555
 556         DBG("get_subbuf");
 557
 558         channel_and_cpu = nth_token(recvbuf, 1);
 559         if(channel_and_cpu == NULL) {
 560                 ERR("cannot parse channel");
 561                 retval = -1;
 562                 goto end;
 563         }
 564
 565         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 566         if(ch_cpu == -1) {
 567                 ERR("problem parsing channel name");
 568                 retval = -1;
 569                 goto free_short_chan_name;
 570         }
 571
 572         ltt_lock_traces();
 573         trace = _ltt_trace_find(trace_name);
 574
 575         if(trace == NULL) {
 576                 int result;
 577
 578                 DBG("Cannot find trace. It was likely destroyed by the user.");
 579                 result = ustcomm_send_reply("NOTFOUND", sock);
 580                 if(result) {
 581                         ERR("ustcomm_send_reply failed");
 582                         retval = -1;
 583                         goto unlock_traces;
 584                 }
 585
 586                 goto unlock_traces;
 587         }
 588
 589         for(i=0; i<trace->nr_channels; i++) {
 590                 struct ust_channel *channel = &trace->channels[i];
 591
 592                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 593                         struct ust_buffer *buf = channel->buf[ch_cpu];
 594                         char *reply;
 595
 596                         found = 1;
 597
 598                         result = ust_buffers_get_subbuf(buf, &consumed_old);
 599                         if(result == -EAGAIN) {
 600                                 WARN("missed buffer?");
 601                                 retval = 0;
 602
 603                                 goto unlock_traces;
 604                         } else if (result < 0) {
 605                                 ERR("ust_buffers_get_subbuf: error: %s", strerror(-result));
 606                                 retval = -1;
 607
 608                                 goto unlock_traces;
 609                         }
 610                         if (asprintf(&reply, "%s %ld", "OK", consumed_old) < 0) {
 611                                 ERR("do_cmd_get_subbuffer: asprintf failed (OK %ld)",
 612                                     consumed_old);
 613                                 retval = -1;
 614
 615                                 goto unlock_traces;
 616                         }
 617                         result = ustcomm_send_reply(reply, sock);
 618                         if (result < 0) {
 619                                 ERR("ustcomm_send_reply failed");
 620                                 free(reply);
 621                                 retval = -1;
 622
 623                                 goto unlock_traces;
 624                         }
 625                         free(reply);
 626
 627                         break;
 628                 }
 629         }
 630         if(found == 0) {
 631                 result = ustcomm_send_reply("NOTFOUND", sock);
 632                 if (result <= 0) {
 633                         ERR("ustcomm_send_reply failed");
 634                         retval = -1;
 635
 636                         goto unlock_traces;
 637                 }
 638                 ERR("unable to find channel");
 639         }
 640
 641         unlock_traces:
 642         ltt_unlock_traces();
 643
 644         free_short_chan_name:
 645         free(ch_name);
 646
 647         end:
 648         return retval;
 649 }
 650
 651
 652 static int do_cmd_get_buffer_fd(const char *recvbuf, int sock)
 653 {
 654         int retval = 0;
 655         struct ust_trace *trace;
 656         char trace_name[] = "auto";
 657         int i;
 658         char *channel_and_cpu;
 659         int found = 0;
 660         char *ch_name;
 661         int ch_cpu;
 662         struct ustcomm_header header;
 663
 664         DBG("get_buffer_fd");
 665
 666         channel_and_cpu = nth_token(recvbuf, 1);
 667         if (channel_and_cpu == NULL) {
 668                 ERR("cannot parse channel");
 669                 retval = -1;
 670                 goto end;
 671         }
 672
 673         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 674         if (ch_cpu == -1) {
 675                 ERR("problem parsing channel name");
 676                 retval = -1;
 677                 goto free_short_chan_name;
 678         }
 679
 680         ltt_lock_traces();
 681         trace = _ltt_trace_find(trace_name);
 682
 683         if (trace == NULL) {
 684                 int result;
 685
 686                 DBG("Cannot find trace. It was likely destroyed by the user.");
 687                 result = ustcomm_send_reply("NOTFOUND", sock);
 688                 if (result) {
 689                         ERR("ustcomm_send_reply failed");
 690                         retval = -1;
 691                         goto unlock_traces;
 692                 }
 693
 694                 goto unlock_traces;
 695         }
 696
 697         for (i=0; i<trace->nr_channels; i++) {
 698                 struct ust_channel *channel = &trace->channels[i];
 699
 700                 if (!strcmp(trace->channels[i].channel_name, ch_name)) {
 701                         struct ust_buffer *buf = channel->buf[ch_cpu];
 702
 703                         found = 1;
 704
 705                         header.size = 0;
 706                         header.fd_included = 1;
 707                         if (ustcomm_send_fd(sock, &header, NULL,
 708                                             &buf->data_ready_fd_read) <= 0) {
 709                                 ERR("ustcomm_send_fd failed\n");
 710                                 goto unlock_traces;
 711                         }
 712
 713                         /* Being here is the proof the daemon has mapped the buffer in its
 714                          * memory. We may now decrement buffers_to_export.
 715                          */
 716                         if (uatomic_read(&buf->consumed) == 0) {
 717                                 DBG("decrementing buffers_to_export");
 718                                 STORE_SHARED(buffers_to_export, LOAD_SHARED(buffers_to_export)-1);
 719                         }
 720
 721                         /* The buffer has been exported, ergo, we can add it to the
 722                          * list of open buffers
 723                          */
 724                         list_add(&buf->open_buffers_list, &open_buffers_list);
 725                         break;
 726                 }
 727         }
 728         if (found == 0) {
 729                 ERR("unable to find channel");
 730         }
 731
 732         unlock_traces:
 733         ltt_unlock_traces();
 734
 735         free_short_chan_name:
 736         free(ch_name);
 737
 738         end:
 739         return retval;
 740 }
 741
 742 static int do_cmd_put_subbuffer(const char *recvbuf, int sock)
 743 {
 744         int retval = 0;
 745         struct ust_trace *trace;
 746         char trace_name[] = "auto";
 747         int i;
 748         char *channel_and_cpu;
 749         int found = 0;
 750         int result;
 751         char *ch_name;
 752         int ch_cpu;
 753         long consumed_old;
 754         char *consumed_old_str;
 755         char *endptr;
 756         char *reply = NULL;
 757
 758         DBG("put_subbuf");
 759
 760         channel_and_cpu = strdup(nth_token(recvbuf, 1));
 761         if (channel_and_cpu == NULL) {
 762                 ERR("cannot parse channel");
 763                 retval = -1;
 764                 goto end;
 765         }
 766
 767         consumed_old_str = strdup(nth_token(recvbuf, 2));
 768         if (consumed_old_str == NULL) {
 769                 ERR("cannot parse consumed_old");
 770                 retval = -1;
 771                 goto free_channel_and_cpu;
 772         }
 773         consumed_old = strtol(consumed_old_str, &endptr, 10);
 774         if (*endptr != '\0') {
 775                 ERR("invalid value for consumed_old");
 776                 retval = -1;
 777                 goto free_consumed_old_str;
 778         }
 779
 780         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 781         if (ch_cpu == -1) {
 782                 ERR("problem parsing channel name");
 783                 retval = -1;
 784                 goto free_short_chan_name;
 785         }
 786
 787         ltt_lock_traces();
 788         trace = _ltt_trace_find(trace_name);
 789
 790         if (trace == NULL) {
 791                 DBG("Cannot find trace. It was likely destroyed by the user.");
 792                 result = ustcomm_send_reply("NOTFOUND", sock);
 793                 if (result) {
 794                         ERR("ustcomm_send_reply failed");
 795                         retval = -1;
 796                         goto unlock_traces;
 797                 }
 798
 799                 goto unlock_traces;
 800         }
 801
 802         for (i=0; i<trace->nr_channels; i++) {
 803                 struct ust_channel *channel = &trace->channels[i];
 804
 805                 if (!strcmp(trace->channels[i].channel_name, ch_name)) {
 806                         struct ust_buffer *buf = channel->buf[ch_cpu];
 807
 808                         found = 1;
 809
 810                         result = ust_buffers_put_subbuf(buf, consumed_old);
 811                         if (result < 0) {
 812                                 WARN("ust_buffers_put_subbuf: error (subbuf=%s)", channel_and_cpu);
 813                                 if (asprintf(&reply, "%s", "ERROR") < 0) {
 814                                         ERR("do_cmd_put_subbuffer : asprintf failed (ERROR)");
 815                                         retval = -1;
 816                                         goto unlock_traces;
 817                                 }
 818                         } else {
 819                                 DBG("ust_buffers_put_subbuf: success (subbuf=%s)", channel_and_cpu);
 820                                 if (asprintf(&reply, "%s", "OK") < 0) {
 821                                         ERR("do_cmd_put_subbuffer : asprintf failed (OK)");
 822                                         retval = -1;
 823                                         goto unlock_traces;
 824                                 }
 825                         }
 826
 827                         result = ustcomm_send_reply(reply, sock);
 828                         if (result) {
 829                                 ERR("ustcomm_send_reply failed");
 830                                 free(reply);
 831                                 retval = -1;
 832                                 goto unlock_traces;
 833                         }
 834
 835                         free(reply);
 836                         break;
 837                 }
 838         }
 839         if (found == 0) {
 840                 ERR("unable to find channel");
 841         }
 842
 843         unlock_traces:
 844         ltt_unlock_traces();
 845         free_short_chan_name:
 846         free(ch_name);
 847         free_consumed_old_str:
 848         free(consumed_old_str);
 849         free_channel_and_cpu:
 850         free(channel_and_cpu);
 851
 852         end:
 853         return retval;
 854 }
 855
 856 static void listener_cleanup(void *ptr)
 857 {
 858         ustcomm_del_named_sock(listen_sock, 0);
 859 }
 860
 861 static void do_cmd_force_switch()
 862 {
 863         struct ust_buffer *buf;
 864
 865         list_for_each_entry(buf, &open_buffers_list,
 866                             open_buffers_list) {
 867                 ltt_force_switch(buf, FORCE_FLUSH);
 868         }
 869 }
 870
 871 static int process_client_cmd(char *recvbuf, int sock)
 872 {
 873         int result;
 874         char trace_name[] = "auto";
 875         char trace_type[] = "ustrelay";
 876         int len;
 877
 878         len = strlen(recvbuf);
 879
 880         if (!strcmp(recvbuf, "print_markers")) {
 881                 print_markers(stderr);
 882         } else if (!strcmp(recvbuf, "list_markers")) {
 883                 char *ptr;
 884                 size_t size;
 885                 FILE *fp;
 886
 887                 fp = open_memstream(&ptr, &size);
 888                 print_markers(fp);
 889                 fclose(fp);
 890
 891                 result = ustcomm_send_reply(ptr, sock);
 892
 893                 free(ptr);
 894         } else if (!strcmp(recvbuf, "print_trace_events")) {
 895                 print_trace_events(stderr);
 896
 897         } else if (!strcmp(recvbuf, "list_trace_events")) {
 898                 char *ptr;
 899                 size_t size;
 900                 FILE *fp;
 901
 902                 fp = open_memstream(&ptr, &size);
 903                 if (fp == NULL) {
 904                         ERR("opening memstream failed");
 905                         return -1;
 906                 }
 907                 print_trace_events(fp);
 908                 fclose(fp);
 909
 910                 result = ustcomm_send_reply(ptr, sock);
 911                 if (result < 0) {
 912                         ERR("list_trace_events failed");
 913                         return -1;
 914                 }
 915                 free(ptr);
 916         } else if (!strcmp(recvbuf, "start")) {
 917                 /* start is an operation that setups the trace, allocates it and starts it */
 918                 result = ltt_trace_setup(trace_name);
 919                 if (result < 0) {
 920                         ERR("ltt_trace_setup failed");
 921                         return -1;
 922                 }
 923
 924                 result = ltt_trace_set_type(trace_name, trace_type);
 925                 if (result < 0) {
 926                         ERR("ltt_trace_set_type failed");
 927                         return -1;
 928                 }
 929
 930                 result = ltt_trace_alloc(trace_name);
 931                 if (result < 0) {
 932                         ERR("ltt_trace_alloc failed");
 933                         return -1;
 934                 }
 935
 936                 inform_consumer_daemon(trace_name);
 937
 938                 result = ltt_trace_start(trace_name);
 939                 if (result < 0) {
 940                         ERR("ltt_trace_start failed");
 941                         return -1;
 942                 }
 943         } else if (!strcmp(recvbuf, "trace_setup")) {
 944                 DBG("trace setup");
 945
 946                 result = ltt_trace_setup(trace_name);
 947                 if (result < 0) {
 948                         ERR("ltt_trace_setup failed");
 949                         return -1;
 950                 }
 951
 952                 result = ltt_trace_set_type(trace_name, trace_type);
 953                 if (result < 0) {
 954                         ERR("ltt_trace_set_type failed");
 955                         return -1;
 956                 }
 957         } else if (!strcmp(recvbuf, "trace_alloc")) {
 958                 DBG("trace alloc");
 959
 960                 result = ltt_trace_alloc(trace_name);
 961                 if (result < 0) {
 962                         ERR("ltt_trace_alloc failed");
 963                         return -1;
 964                 }
 965                 inform_consumer_daemon(trace_name);
 966         } else if (!strcmp(recvbuf, "trace_create")) {
 967                 DBG("trace create");
 968
 969                 result = ltt_trace_setup(trace_name);
 970                 if (result < 0) {
 971                         ERR("ltt_trace_setup failed");
 972                         return -1;
 973                 }
 974
 975                 result = ltt_trace_set_type(trace_name, trace_type);
 976                 if (result < 0) {
 977                         ERR("ltt_trace_set_type failed");
 978                         return -1;
 979                 }
 980         } else if (!strcmp(recvbuf, "trace_start")) {
 981                 DBG("trace start");
 982
 983                 result = ltt_trace_alloc(trace_name);
 984                 if (result < 0) {
 985                         ERR("ltt_trace_alloc failed");
 986                         return -1;
 987                 }
 988                 if (!result) {
 989                         inform_consumer_daemon(trace_name);
 990                 }
 991
 992                 result = ltt_trace_start(trace_name);
 993                 if (result < 0) {
 994                         ERR("ltt_trace_start failed");
 995                         return -1;
 996                 }
 997         } else if (!strcmp(recvbuf, "trace_stop")) {
 998                 DBG("trace stop");
 999
1000                 result = ltt_trace_stop(trace_name);
1001                 if (result < 0) {
1002                         ERR("ltt_trace_stop failed");
1003                         return -1;
1004                 }
1005         } else if (!strcmp(recvbuf, "trace_destroy")) {
1006
1007                 DBG("trace destroy");
1008
1009                 result = ltt_trace_destroy(trace_name, 0);
1010                 if (result < 0) {
1011                         ERR("ltt_trace_destroy failed");
1012                         return -1;
1013                 }
1014         } else if (nth_token_is(recvbuf, "get_shmid", 0) == 1) {
1015                 do_cmd_get_shmid(recvbuf, sock);
1016         } else if (nth_token_is(recvbuf, "get_n_subbufs", 0) == 1) {
1017                 do_cmd_get_n_subbufs(recvbuf, sock);
1018         } else if (nth_token_is(recvbuf, "get_subbuf_size", 0) == 1) {
1019                 do_cmd_get_subbuf_size(recvbuf, sock);
1020         } else if (nth_token_is(recvbuf, "load_probe_lib", 0) == 1) {
1021                 char *libfile;
1022
1023                 libfile = nth_token(recvbuf, 1);
1024
1025                 DBG("load_probe_lib loading %s", libfile);
1026
1027                 free(libfile);
1028         } else if (nth_token_is(recvbuf, "get_subbuffer", 0) == 1) {
1029                 do_cmd_get_subbuffer(recvbuf, sock);
1030         }
1031         else if(nth_token_is(recvbuf, "get_buffer_fd", 0) == 1) {
1032                 do_cmd_get_buffer_fd(recvbuf, sock);
1033         }
1034         else if(nth_token_is(recvbuf, "put_subbuffer", 0) == 1) {
1035                 do_cmd_put_subbuffer(recvbuf, sock);
1036         } else if (nth_token_is(recvbuf, "set_subbuf_size", 0) == 1) {
1037                 do_cmd_set_subbuf_size(recvbuf, sock);
1038         } else if (nth_token_is(recvbuf, "set_subbuf_num", 0) == 1) {
1039                 do_cmd_set_subbuf_num(recvbuf, sock);
1040         } else if (nth_token_is(recvbuf, "enable_marker", 0) == 1) {
1041                 char *channel_slash_name = nth_token(recvbuf, 1);
1042                 char *channel_name = NULL;
1043                 char *marker_name = NULL;
1044
1045                 result = sscanf(channel_slash_name, "%a[^/]/%as", &channel_name, &marker_name);
1046
1047                 if (channel_name == NULL || marker_name == NULL) {
1048                         WARN("invalid marker name");
1049                         free(channel_name);
1050                         free(marker_name);
1051                         goto next_cmd;
1052                 }
1053
1054                 result = ltt_marker_connect(channel_name, marker_name, "default");
1055                 if (result < 0) {
1056                         WARN("could not enable marker; channel=%s, name=%s", channel_name, marker_name);
1057                 }
1058
1059                 free(channel_name);
1060                 free(marker_name);
1061         } else if (nth_token_is(recvbuf, "disable_marker", 0) == 1) {
1062                 char *channel_slash_name = nth_token(recvbuf, 1);
1063                 char *marker_name = NULL;
1064                 char *channel_name = NULL;
1065
1066                 result = sscanf(channel_slash_name, "%a[^/]/%as", &channel_name, &marker_name);
1067
1068                 if (channel_name == NULL || marker_name == NULL) {
1069                         WARN("invalid marker name");
1070                         free(channel_name);
1071                         free(marker_name);
1072                         goto next_cmd;
1073                 }
1074
1075                 result = ltt_marker_disconnect(channel_name, marker_name, "default");
1076                 if (result < 0) {
1077                         WARN("could not disable marker; channel=%s, name=%s", channel_name, marker_name);
1078                 }
1079
1080                 free(channel_name);
1081                 free(marker_name);
1082         } else if (nth_token_is(recvbuf, "get_pidunique", 0) == 1) {
1083                 char *reply;
1084
1085                 if (asprintf(&reply, "%lld", pidunique) < 0) {
1086                         ERR("process_client_cmd : asprintf failed (%lld)",
1087                             pidunique);
1088                         goto next_cmd;
1089                 }
1090
1091                 result = ustcomm_send_reply(reply, sock);
1092                 if (result) {
1093                         ERR("listener: get_pidunique: ustcomm_send_reply failed");
1094                         goto next_cmd;
1095                 }
1096
1097                 free(reply);
1098         } else if (nth_token_is(recvbuf, "get_sock_path", 0) == 1) {
1099                 char *reply = getenv("UST_DAEMON_SOCKET");
1100                 if (!reply) {
1101                         if (asprintf(&reply, "%s/%s", SOCK_DIR, "ustd") < 0) {
1102                                 ERR("process_client_cmd : asprintf failed (%s/ustd)",
1103                                     SOCK_DIR);
1104                                 goto next_cmd;
1105                         }
1106                         result = ustcomm_send_reply(reply, sock);
1107                         free(reply);
1108                 } else {
1109                         result = ustcomm_send_reply(reply, sock);
1110                 }
1111                 if (result)
1112                         ERR("ustcomm_send_reply failed");
1113         } else if (nth_token_is(recvbuf, "set_sock_path", 0) == 1) {
1114                 char *sock_path = nth_token(recvbuf, 1);
1115                 result = setenv("UST_DAEMON_SOCKET", sock_path, 1);
1116                 if (result)
1117                         ERR("cannot set UST_DAEMON_SOCKET environment variable");
1118         } else if (nth_token_is(recvbuf, "force_switch", 0) == 1) {
1119                 do_cmd_force_switch();
1120         } else {
1121                 ERR("unable to parse message: %s", recvbuf);
1122         }
1123
1124 next_cmd:
1125
1126         return 0;
1127 }
1128
1129 #define MAX_EVENTS 10
1130
1131 void *listener_main(void *p)
1132 {
1133         struct ustcomm_sock *epoll_sock;
1134         struct epoll_event events[MAX_EVENTS];
1135         struct sockaddr addr;
1136         int accept_fd, nfds, result, i, addr_size;
1137
1138         DBG("LISTENER");
1139
1140         pthread_cleanup_push(listener_cleanup, NULL);
1141
1142         for(;;) {
1143                 nfds = epoll_wait(epoll_fd, events, MAX_EVENTS, -1);
1144                 if (nfds == -1) {
1145                         PERROR("listener_main: epoll_wait failed");
1146                         continue;
1147                 }
1148
1149                 for (i = 0; i < nfds; i++) {
1150                         epoll_sock = (struct ustcomm_sock *)events[i].data.ptr;
1151                         if (epoll_sock == listen_sock) {
1152                                 addr_size = sizeof(struct sockaddr);
1153                                 accept_fd = accept(epoll_sock->fd,
1154                                                    &addr,
1155                                                    (socklen_t *)&addr_size);
1156                                 if (accept_fd == -1) {
1157                                         PERROR("listener_main: accept failed");
1158                                         continue;
1159                                 }
1160                                 ustcomm_init_sock(accept_fd, epoll_fd,
1161                                                  &ust_socks);
1162                         } else {
1163                                 char *msg = NULL;
1164                                 result = recv_message_conn(epoll_sock->fd, &msg);
1165                                 if (result == 0) {
1166                                         ustcomm_del_sock(epoll_sock, 0);
1167                                 } else if (msg) {
1168                                         process_client_cmd(msg, epoll_sock->fd);
1169                                         free(msg);
1170                                 }
1171                         }
1172                 }
1173         }
1174
1175         pthread_cleanup_pop(1);
1176 }
1177
1178 /* These should only be accessed in the parent thread,
1179  * not the listener.
1180  */
1181 static volatile sig_atomic_t have_listener = 0;
1182 static pthread_t listener_thread;
1183
1184 void create_listener(void)
1185 {
1186         int result;
1187         sigset_t sig_all_blocked;
1188         sigset_t orig_parent_mask;
1189
1190         if (have_listener) {
1191                 WARN("not creating listener because we already had one");
1192                 return;
1193         }
1194
1195         /* A new thread created by pthread_create inherits the signal mask
1196          * from the parent. To avoid any signal being received by the
1197          * listener thread, we block all signals temporarily in the parent,
1198          * while we create the listener thread.
1199          */
1200
1201         sigfillset(&sig_all_blocked);
1202
1203         result = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
1204         if (result) {
1205                 PERROR("pthread_sigmask: %s", strerror(result));
1206         }
1207
1208         result = pthread_create(&listener_thread, NULL, listener_main, NULL);
1209         if (result == -1) {
1210                 PERROR("pthread_create");
1211         }
1212
1213         /* Restore original signal mask in parent */
1214         result = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
1215         if (result) {
1216                 PERROR("pthread_sigmask: %s", strerror(result));
1217         } else {
1218                 have_listener = 1;
1219         }
1220 }
1221
1222 #define AUTOPROBE_DISABLED      0
1223 #define AUTOPROBE_ENABLE_ALL    1
1224 #define AUTOPROBE_ENABLE_REGEX  2
1225 static int autoprobe_method = AUTOPROBE_DISABLED;
1226 static regex_t autoprobe_regex;
1227
1228 static void auto_probe_connect(struct marker *m)
1229 {
1230         int result;
1231
1232         char* concat_name = NULL;
1233         const char *probe_name = "default";
1234
1235         if (autoprobe_method == AUTOPROBE_DISABLED) {
1236                 return;
1237         } else if (autoprobe_method == AUTOPROBE_ENABLE_REGEX) {
1238                 result = asprintf(&concat_name, "%s/%s", m->channel, m->name);
1239                 if (result == -1) {
1240                         ERR("auto_probe_connect: asprintf failed (marker %s/%s)",
1241                                 m->channel, m->name);
1242                         return;
1243                 }
1244                 if (regexec(&autoprobe_regex, concat_name, 0, NULL, 0)) {
1245                         free(concat_name);
1246                         return;
1247                 }
1248                 free(concat_name);
1249         }
1250
1251         result = ltt_marker_connect(m->channel, m->name, probe_name);
1252         if (result && result != -EEXIST)
1253                 ERR("ltt_marker_connect (marker = %s/%s, errno = %d)", m->channel, m->name, -result);
1254
1255         DBG("auto connected marker %s (addr: %p) %s to probe default", m->channel, m, m->name);
1256
1257 }
1258
1259 static struct ustcomm_sock * init_app_socket(int epoll_fd)
1260 {
1261         char *name;
1262         int result;
1263         struct ustcomm_sock *sock;
1264
1265         result = asprintf(&name, "%s/%d", SOCK_DIR, (int)getpid());
1266         if (result < 0) {
1267                 ERR("string overflow allocating socket name, "
1268                     "UST thread bailing");
1269                 return NULL;
1270         }
1271
1272         result = ensure_dir_exists(SOCK_DIR);
1273         if (result == -1) {
1274                 ERR("Unable to create socket directory %s, UST thread bailing",
1275                     SOCK_DIR);
1276                 goto free_name;
1277         }
1278
1279         sock = ustcomm_init_named_socket(name, epoll_fd);
1280         if (!sock) {
1281                 ERR("Error initializing named socket (%s). Check that directory"
1282                     "exists and that it is writable. UST thread bailing", name);
1283                 goto free_name;
1284         }
1285
1286         free(name);
1287         return sock;
1288
1289 free_name:
1290         free(name);
1291         return NULL;
1292 }
1293
1294 static void __attribute__((constructor)) init()
1295 {
1296         int result;
1297         char* autoprobe_val = NULL;
1298         char* subbuffer_size_val = NULL;
1299         char* subbuffer_count_val = NULL;
1300         unsigned int subbuffer_size;
1301         unsigned int subbuffer_count;
1302         unsigned int power;
1303
1304         /* Assign the pidunique, to be able to differentiate the processes with same
1305          * pid, (before and after an exec).
1306          */
1307         pidunique = make_pidunique();
1308
1309         DBG("Tracectl constructor");
1310
1311         /* Set up epoll */
1312         epoll_fd = epoll_create(MAX_EVENTS);
1313         if (epoll_fd == -1) {
1314                 ERR("epoll_create failed, tracing shutting down");
1315                 return;
1316         }
1317
1318         /* Create the socket */
1319         listen_sock = init_app_socket(epoll_fd);
1320         if (!listen_sock) {
1321                 ERR("failed to create application socket,"
1322                     " tracing shutting down");
1323                 return;
1324         }
1325
1326         create_listener();
1327
1328         autoprobe_val = getenv("UST_AUTOPROBE");
1329         if (autoprobe_val) {
1330                 struct marker_iter iter;
1331
1332                 DBG("Autoprobe enabled.");
1333
1334                 /* Ensure markers are initialized */
1335                 //init_markers();
1336
1337                 /* Ensure marker control is initialized, for the probe */
1338                 init_marker_control();
1339
1340                 /* first, set the callback that will connect the
1341                  * probe on new markers
1342                  */
1343                 if (autoprobe_val[0] == '/') {
1344                         result = regcomp(&autoprobe_regex, autoprobe_val+1, 0);
1345                         if (result) {
1346                                 char regexerr[150];
1347
1348                                 regerror(result, &autoprobe_regex, regexerr, sizeof(regexerr));
1349                                 ERR("cannot parse regex %s (%s), will ignore UST_AUTOPROBE", autoprobe_val, regexerr);
1350                                 /* don't crash the application just for this */
1351                         } else {
1352                                 autoprobe_method = AUTOPROBE_ENABLE_REGEX;
1353                         }
1354                 } else {
1355                         /* just enable all instrumentation */
1356                         autoprobe_method = AUTOPROBE_ENABLE_ALL;
1357                 }
1358
1359                 marker_set_new_marker_cb(auto_probe_connect);
1360
1361                 /* Now, connect the probes that were already registered. */
1362                 marker_iter_reset(&iter);
1363                 marker_iter_start(&iter);
1364
1365                 DBG("now iterating on markers already registered");
1366                 while (iter.marker) {
1367                         DBG("now iterating on marker %s", iter.marker->name);
1368                         auto_probe_connect(iter.marker);
1369                         marker_iter_next(&iter);
1370                 }
1371         }
1372
1373         if (getenv("UST_OVERWRITE")) {
1374                 int val = atoi(getenv("UST_OVERWRITE"));
1375                 if (val == 0 || val == 1) {
1376                         STORE_SHARED(ust_channels_overwrite_by_default, val);
1377                 } else {
1378                         WARN("invalid value for UST_OVERWRITE");
1379                 }
1380         }
1381
1382         if (getenv("UST_AUTOCOLLECT")) {
1383                 int val = atoi(getenv("UST_AUTOCOLLECT"));
1384                 if (val == 0 || val == 1) {
1385                         STORE_SHARED(ust_channels_request_collection_by_default, val);
1386                 } else {
1387                         WARN("invalid value for UST_AUTOCOLLECT");
1388                 }
1389         }
1390
1391         subbuffer_size_val = getenv("UST_SUBBUF_SIZE");
1392         if (subbuffer_size_val) {
1393                 sscanf(subbuffer_size_val, "%u", &subbuffer_size);
1394                 power = pow2_higher_or_eq(subbuffer_size);
1395                 if (power != subbuffer_size)
1396                         WARN("using the next power of two for buffer size = %u\n", power);
1397                 chan_infos[LTT_CHANNEL_UST].def_subbufsize = power;
1398         }
1399
1400         subbuffer_count_val = getenv("UST_SUBBUF_NUM");
1401         if (subbuffer_count_val) {
1402                 sscanf(subbuffer_count_val, "%u", &subbuffer_count);
1403                 if (subbuffer_count < 2)
1404                         subbuffer_count = 2;
1405                 chan_infos[LTT_CHANNEL_UST].def_subbufcount = subbuffer_count;
1406         }
1407
1408         if (getenv("UST_TRACE")) {
1409                 char trace_name[] = "auto";
1410                 char trace_type[] = "ustrelay";
1411
1412                 DBG("starting early tracing");
1413
1414                 /* Ensure marker control is initialized */
1415                 init_marker_control();
1416
1417                 /* Ensure markers are initialized */
1418                 init_markers();
1419
1420                 /* Ensure buffers are initialized, for the transport to be available.
1421                  * We are about to set a trace type and it will fail without this.
1422                  */
1423                 init_ustrelay_transport();
1424
1425                 /* FIXME: When starting early tracing (here), depending on the
1426                  * order of constructors, it is very well possible some marker
1427                  * sections are not yet registered. Because of this, some
1428                  * channels may not be registered. Yet, we are about to ask the
1429                  * daemon to collect the channels. Channels which are not yet
1430                  * registered will not be collected.
1431                  *
1432                  * Currently, in LTTng, there is no way to add a channel after
1433                  * trace start. The reason for this is that it induces complex
1434                  * concurrency issues on the trace structures, which can only
1435                  * be resolved using RCU. This has not been done yet. As a
1436                  * workaround, we are forcing the registration of the "ust"
1437                  * channel here. This is the only channel (apart from metadata)
1438                  * that can be reliably used in early tracing.
1439                  *
1440                  * Non-early tracing does not have this problem and can use
1441                  * arbitrary channel names.
1442                  */
1443                 ltt_channels_register("ust");
1444
1445                 result = ltt_trace_setup(trace_name);
1446                 if (result < 0) {
1447                         ERR("ltt_trace_setup failed");
1448                         return;
1449                 }
1450
1451                 result = ltt_trace_set_type(trace_name, trace_type);
1452                 if (result < 0) {
1453                         ERR("ltt_trace_set_type failed");
1454                         return;
1455                 }
1456
1457                 result = ltt_trace_alloc(trace_name);
1458                 if (result < 0) {
1459                         ERR("ltt_trace_alloc failed");
1460                         return;
1461                 }
1462
1463                 result = ltt_trace_start(trace_name);
1464                 if (result < 0) {
1465                         ERR("ltt_trace_start failed");
1466                         return;
1467                 }
1468
1469                 /* Do this after the trace is started in order to avoid creating confusion
1470                  * if the trace fails to start. */
1471                 inform_consumer_daemon(trace_name);
1472         }
1473
1474         return;
1475
1476         /* should decrementally destroy stuff if error */
1477
1478 }
1479
1480 /* This is only called if we terminate normally, not with an unhandled signal,
1481  * so we cannot rely on it. However, for now, LTTV requires that the header of
1482  * the last sub-buffer contain a valid end time for the trace. This is done
1483  * automatically only when the trace is properly stopped.
1484  *
1485  * If the traced program crashed, it is always possible to manually add the
1486  * right value in the header, or to open the trace in text mode.
1487  *
1488  * FIXME: Fix LTTV so it doesn't need this.
1489  */
1490
1491 static void destroy_traces(void)
1492 {
1493         int result;
1494
1495         /* if trace running, finish it */
1496
1497         DBG("destructor stopping traces");
1498
1499         result = ltt_trace_stop("auto");
1500         if (result == -1) {
1501                 ERR("ltt_trace_stop error");
1502         }
1503
1504         result = ltt_trace_destroy("auto", 0);
1505         if (result == -1) {
1506                 ERR("ltt_trace_destroy error");
1507         }
1508 }
1509
1510 static int trace_recording(void)
1511 {
1512         int retval = 0;
1513         struct ust_trace *trace;
1514
1515         ltt_lock_traces();
1516
1517         list_for_each_entry(trace, &ltt_traces.head, list) {
1518                 if (trace->active) {
1519                         retval = 1;
1520                         break;
1521                 }
1522         }
1523
1524         ltt_unlock_traces();
1525
1526         return retval;
1527 }
1528
1529 int restarting_usleep(useconds_t usecs)
1530 {
1531         struct timespec tv;
1532         int result;
1533
1534         tv.tv_sec = 0;
1535         tv.tv_nsec = usecs * 1000;
1536
1537         do {
1538                 result = nanosleep(&tv, &tv);
1539         } while (result == -1 && errno == EINTR);
1540
1541         return result;
1542 }
1543
1544 static void stop_listener(void)
1545 {
1546         int result;
1547
1548         if (!have_listener)
1549                 return;
1550
1551         result = pthread_cancel(listener_thread);
1552         if (result != 0) {
1553                 ERR("pthread_cancel: %s", strerror(result));
1554         }
1555         result = pthread_join(listener_thread, NULL);
1556         if (result != 0) {
1557                 ERR("pthread_join: %s", strerror(result));
1558         }
1559 }
1560
1561 /* This destructor keeps the process alive for a few seconds in order
1562  * to leave time to ustd to connect to its buffers. This is necessary
1563  * for programs whose execution is very short. It is also useful in all
1564  * programs when tracing is started close to the end of the program
1565  * execution.
1566  *
1567  * FIXME: For now, this only works for the first trace created in a
1568  * process.
1569  */
1570
1571 static void __attribute__((destructor)) keepalive()
1572 {
1573         if (trace_recording() && LOAD_SHARED(buffers_to_export)) {
1574                 int total = 0;
1575                 DBG("Keeping process alive for consumer daemon...");
1576                 while (LOAD_SHARED(buffers_to_export)) {
1577                         const int interv = 200000;
1578                         restarting_usleep(interv);
1579                         total += interv;
1580
1581                         if (total >= 3000000) {
1582                                 WARN("non-consumed buffers remaining after wait limit; not waiting anymore");
1583                                 break;
1584                         }
1585                 }
1586                 DBG("Finally dying...");
1587         }
1588
1589         destroy_traces();
1590
1591         /* Ask the listener to stop and clean up. */
1592         stop_listener();
1593 }
1594
1595 void ust_potential_exec(void)
1596 {
1597         trace_mark(ust, potential_exec, MARK_NOARGS);
1598
1599         DBG("test");
1600
1601         keepalive();
1602 }
1603
1604 /* Notify ust that there was a fork. This needs to be called inside
1605  * the new process, anytime a process whose memory is not shared with
1606  * the parent is created. If this function is not called, the events
1607  * of the new process will not be collected.
1608  *
1609  * Signals should be disabled before the fork and reenabled only after
1610  * this call in order to guarantee tracing is not started before ust_fork()
1611  * sanitizes the new process.
1612  */
1613
1614 static void ust_fork(void)
1615 {
1616         struct ust_buffer *buf, *buf_tmp;
1617         struct ustcomm_sock *sock, *sock_tmp;
1618         int result;
1619
1620         /* FIXME: technically, the locks could have been taken before the fork */
1621         DBG("ust: forking");
1622
1623         /* break lock if necessary */
1624         ltt_unlock_traces();
1625
1626         ltt_trace_stop("auto");
1627         ltt_trace_destroy("auto", 1);
1628         /* Delete all active connections, but leave them in the epoll set */
1629         list_for_each_entry_safe(sock, sock_tmp, &ust_socks, list) {
1630                 ustcomm_del_sock(sock, 1);
1631         }
1632
1633         /* Delete all blocked consumers */
1634         list_for_each_entry_safe(buf, buf_tmp, &open_buffers_list,
1635                                  open_buffers_list) {
1636                 result = close(buf->data_ready_fd_read);
1637                 if(result == -1) {
1638                         PERROR("close");
1639                 }
1640                 result = close(buf->data_ready_fd_write);
1641                 if(result == -1) {
1642                         PERROR("close");
1643                 }
1644                 list_del(&buf->open_buffers_list);
1645         }
1646
1647         /* Clean up the listener socket and epoll, keeping the scoket file */
1648         ustcomm_del_named_sock(listen_sock, 1);
1649         close(epoll_fd);
1650
1651         /* Re-start the launch sequence */
1652         STORE_SHARED(buffers_to_export, 0);
1653         have_listener = 0;
1654
1655         /* Set up epoll */
1656         epoll_fd = epoll_create(MAX_EVENTS);
1657         if (epoll_fd == -1) {
1658                 ERR("epoll_create failed, tracing shutting down");
1659                 return;
1660         }
1661
1662         /* Create the socket */
1663         listen_sock = init_app_socket(epoll_fd);
1664         if (!listen_sock) {
1665                 ERR("failed to create application socket,"
1666                     " tracing shutting down");
1667                 return;
1668         }
1669         create_listener();
1670         ltt_trace_setup("auto");
1671         result = ltt_trace_set_type("auto", "ustrelay");
1672         if (result < 0) {
1673                 ERR("ltt_trace_set_type failed");
1674                 return;
1675         }
1676
1677         ltt_trace_alloc("auto");
1678         ltt_trace_start("auto");
1679         inform_consumer_daemon("auto");
1680 }
1681
1682 void ust_before_fork(ust_fork_info_t *fork_info)
1683 {
1684         /* Disable signals. This is to avoid that the child
1685          * intervenes before it is properly setup for tracing. It is
1686          * safer to disable all signals, because then we know we are not
1687          * breaking anything by restoring the original mask.
1688          */
1689         sigset_t all_sigs;
1690         int result;
1691
1692         /* FIXME:
1693                 - only do this if tracing is active
1694         */
1695
1696         /* Disable signals */
1697         sigfillset(&all_sigs);
1698         result = sigprocmask(SIG_BLOCK, &all_sigs, &fork_info->orig_sigs);
1699         if (result == -1) {
1700                 PERROR("sigprocmask");
1701                 return;
1702         }
1703 }
1704
1705 /* Don't call this function directly in a traced program */
1706 static void ust_after_fork_common(ust_fork_info_t *fork_info)
1707 {
1708         int result;
1709
1710         /* Restore signals */
1711         result = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL);
1712         if (result == -1) {
1713                 PERROR("sigprocmask");
1714                 return;
1715         }
1716 }
1717
1718 void ust_after_fork_parent(ust_fork_info_t *fork_info)
1719 {
1720         /* Reenable signals */
1721         ust_after_fork_common(fork_info);
1722 }
1723
1724 void ust_after_fork_child(ust_fork_info_t *fork_info)
1725 {
1726         /* First sanitize the child */
1727         ust_fork();
1728
1729         /* Then reenable interrupts */
1730         ust_after_fork_common(fork_info);
1731 }
1732