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/types.h>
  30 #include <sys/socket.h>
  31 #include <sys/un.h>
  32 #include <fcntl.h>
  33 #include <poll.h>
  34 #include <regex.h>
  35 #include <urcu/uatomic_arch.h>
  36
  37 #include <ust/marker.h>
  38 #include <ust/tracectl.h>
  39 #include "tracer.h"
  40 #include "usterr.h"
  41 #include "ustcomm.h"
  42 #include "buffers.h"
  43 #include "marker-control.h"
  44 #include "multipoll.h"
  45
  46 #define USTSIGNAL SIGIO
  47
  48 #define MAX_MSG_SIZE (100)
  49 #define MSG_NOTIF 1
  50 #define MSG_REGISTER_NOTIF 2
  51
  52 /* This should only be accessed by the constructor, before the creation
  53  * of the listener, and then only by the listener.
  54  */
  55 s64 pidunique = -1LL;
  56
  57 extern struct chan_info_struct chan_infos[];
  58
  59 struct list_head blocked_consumers = LIST_HEAD_INIT(blocked_consumers);
  60
  61 static struct ustcomm_app ustcomm_app;
  62
  63 struct tracecmd { /* no padding */
  64         uint32_t size;
  65         uint16_t command;
  66 };
  67
  68 /* volatile because shared between the listener and the main thread */
  69 int buffers_to_export = 0;
  70
  71 struct trctl_msg {
  72         /* size: the size of all the fields except size itself */
  73         uint32_t size;
  74         uint16_t type;
  75         /* Only the necessary part of the payload is transferred. It
  76          * may even be none of it.
  77          */
  78         char payload[94];
  79 };
  80
  81 struct consumer_channel {
  82         int fd;
  83         struct ltt_channel_struct *chan;
  84 };
  85
  86 struct blocked_consumer {
  87         int fd_consumer;
  88         int fd_producer;
  89         int tmp_poll_idx;
  90
  91         /* args to ustcomm_send_reply */
  92         struct ustcomm_server server;
  93         struct ustcomm_source src;
  94
  95         /* args to ust_buffers_get_subbuf */
  96         struct ust_buffer *buf;
  97
  98         struct list_head list;
  99 };
 100
 101 static long long make_pidunique(void)
 102 {
 103         s64 retval;
 104         struct timeval tv;
 105
 106         gettimeofday(&tv, NULL);
 107
 108         retval = tv.tv_sec;
 109         retval <<= 32;
 110         retval |= tv.tv_usec;
 111
 112         return retval;
 113 }
 114
 115 static void print_markers(FILE *fp)
 116 {
 117         struct marker_iter iter;
 118
 119         lock_markers();
 120         marker_iter_reset(&iter);
 121         marker_iter_start(&iter);
 122
 123         while(iter.marker) {
 124                 fprintf(fp, "marker: %s/%s %d \"%s\" %p\n", iter.marker->channel, iter.marker->name, (int)imv_read(iter.marker->state), iter.marker->format, iter.marker->location);
 125                 marker_iter_next(&iter);
 126         }
 127         unlock_markers();
 128 }
 129
 130 static int init_socket(void);
 131
 132 /* Ask the daemon to collect a trace called trace_name and being
 133  * produced by this pid.
 134  *
 135  * The trace must be at least allocated. (It can also be started.)
 136  * This is because _ltt_trace_find is used.
 137  */
 138
 139 static void inform_consumer_daemon(const char *trace_name)
 140 {
 141         int i,j;
 142         struct ust_trace *trace;
 143         pid_t pid = getpid();
 144         int result;
 145
 146         ltt_lock_traces();
 147
 148         trace = _ltt_trace_find(trace_name);
 149         if(trace == NULL) {
 150                 WARN("inform_consumer_daemon: could not find trace \"%s\"; it is probably already destroyed", trace_name);
 151                 goto finish;
 152         }
 153
 154         for(i=0; i < trace->nr_channels; i++) {
 155                 if(trace->channels[i].request_collection) {
 156                         /* iterate on all cpus */
 157                         for(j=0; j<trace->channels[i].n_cpus; j++) {
 158                                 char *buf;
 159                                 if (asprintf(&buf, "%s_%d", trace->channels[i].channel_name, j) < 0) {
 160                                        ERR("inform_consumer_daemon : asprintf failed (%s_%d)",
 161                                            trace->channels[i].channel_name, j);
 162                                        goto finish;
 163                                 }
 164                                 result = ustcomm_request_consumer(pid, buf);
 165                                 if(result == -1) {
 166                                         WARN("Failed to request collection for channel %s. Is the daemon available?", trace->channels[i].channel_name);
 167                                         /* continue even if fail */
 168                                 }
 169                                 free(buf);
 170                                 STORE_SHARED(buffers_to_export, LOAD_SHARED(buffers_to_export)+1);
 171                         }
 172                 }
 173         }
 174
 175         finish:
 176         ltt_unlock_traces();
 177 }
 178
 179 int process_blkd_consumer_act(void *priv, int fd, short events)
 180 {
 181         int result;
 182         long consumed_old = 0;
 183         char *reply;
 184         struct blocked_consumer *bc = (struct blocked_consumer *) priv;
 185         char inbuf;
 186
 187         result = read(bc->fd_producer, &inbuf, 1);
 188         if(result == -1) {
 189                 PERROR("read");
 190                 return -1;
 191         }
 192         if(result == 0) {
 193                 int res;
 194                 DBG("listener: got messsage that a buffer ended");
 195
 196                 res = close(bc->fd_producer);
 197                 if(res == -1) {
 198                         PERROR("close");
 199                 }
 200
 201                 list_del(&bc->list);
 202
 203                 result = ustcomm_send_reply(&bc->server, "END", &bc->src);
 204                 if(result < 0) {
 205                         ERR("ustcomm_send_reply failed");
 206                         return -1;
 207                 }
 208
 209                 return 0;
 210         }
 211
 212         result = ust_buffers_get_subbuf(bc->buf, &consumed_old);
 213         if(result == -EAGAIN) {
 214                 WARN("missed buffer?");
 215                 return 0;
 216         }
 217         else if(result < 0) {
 218                 ERR("ust_buffers_get_subbuf: error: %s", strerror(-result));
 219         }
 220         if (asprintf(&reply, "%s %ld", "OK", consumed_old) < 0) {
 221                ERR("process_blkd_consumer_act : asprintf failed (OK %ld)",
 222                    consumed_old);
 223                return -1;
 224         }
 225         result = ustcomm_send_reply(&bc->server, reply, &bc->src);
 226         if(result < 0) {
 227                 ERR("ustcomm_send_reply failed");
 228                 free(reply);
 229                 return -1;
 230         }
 231         free(reply);
 232
 233         list_del(&bc->list);
 234
 235         return 0;
 236 }
 237
 238 void blocked_consumers_add_to_mp(struct mpentries *ent)
 239 {
 240         struct blocked_consumer *bc;
 241
 242         list_for_each_entry(bc, &blocked_consumers, list) {
 243                 multipoll_add(ent, bc->fd_producer, POLLIN, process_blkd_consumer_act, bc, NULL);
 244         }
 245
 246 }
 247
 248 void seperate_channel_cpu(const char *channel_and_cpu, char **channel, int *cpu)
 249 {
 250         const char *sep;
 251
 252         sep = rindex(channel_and_cpu, '_');
 253         if(sep == NULL) {
 254                 *cpu = -1;
 255                 sep = channel_and_cpu + strlen(channel_and_cpu);
 256         }
 257         else {
 258                 *cpu = atoi(sep+1);
 259         }
 260
 261         if (asprintf(channel, "%.*s", (int)(sep-channel_and_cpu), channel_and_cpu) < 0) {
 262                 ERR("seperate_channel_cpu : asprintf failed (%.*s)",
 263                     (int)(sep-channel_and_cpu), channel_and_cpu);
 264                 return;
 265         }
 266 }
 267
 268 static int do_cmd_get_shmid(const char *recvbuf, struct ustcomm_source *src)
 269 {
 270         int retval = 0;
 271         struct ust_trace *trace;
 272         char trace_name[] = "auto";
 273         int i;
 274         char *channel_and_cpu;
 275         int found = 0;
 276         int result;
 277         char *ch_name;
 278         int ch_cpu;
 279
 280         DBG("get_shmid");
 281
 282         channel_and_cpu = nth_token(recvbuf, 1);
 283         if(channel_and_cpu == NULL) {
 284                 ERR("cannot parse channel");
 285                 retval = -1;
 286                 goto end;
 287         }
 288
 289         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 290         if(ch_cpu == -1) {
 291                 ERR("problem parsing channel name");
 292                 retval = -1;
 293                 goto free_short_chan_name;
 294         }
 295
 296         ltt_lock_traces();
 297         trace = _ltt_trace_find(trace_name);
 298         ltt_unlock_traces();
 299
 300         if(trace == NULL) {
 301                 ERR("cannot find trace!");
 302                 retval = -1;
 303                 goto free_short_chan_name;
 304         }
 305
 306         for(i=0; i<trace->nr_channels; i++) {
 307                 struct ust_channel *channel = &trace->channels[i];
 308                 struct ust_buffer *buf = channel->buf[ch_cpu];
 309
 310                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 311                         char *reply;
 312
 313 //                      DBG("the shmid for the requested channel is %d", buf->shmid);
 314 //                      DBG("the shmid for its buffer structure is %d", channel->buf_struct_shmids);
 315                         if (asprintf(&reply, "%d %d", buf->shmid, channel->buf_struct_shmids[ch_cpu]) < 0) {
 316                                 ERR("do_cmd_get_shmid : asprintf failed (%d %d)",
 317                                     buf->shmid, channel->buf_struct_shmids[ch_cpu]);
 318                                 retval = -1;
 319                                 goto free_short_chan_name;
 320                         }
 321
 322                         result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
 323                         if(result) {
 324                                 ERR("ustcomm_send_reply failed");
 325                                 free(reply);
 326                                 retval = -1;
 327                                 goto free_short_chan_name;
 328                         }
 329
 330                         free(reply);
 331
 332                         found = 1;
 333                         break;
 334                 }
 335         }
 336
 337         if(!found) {
 338                 ERR("channel not found (%s)", channel_and_cpu);
 339         }
 340
 341         free_short_chan_name:
 342         free(ch_name);
 343
 344         end:
 345         return retval;
 346 }
 347
 348 static int do_cmd_get_n_subbufs(const char *recvbuf, struct ustcomm_source *src)
 349 {
 350         int retval = 0;
 351         struct ust_trace *trace;
 352         char trace_name[] = "auto";
 353         int i;
 354         char *channel_and_cpu;
 355         int found = 0;
 356         int result;
 357         char *ch_name;
 358         int ch_cpu;
 359
 360         DBG("get_n_subbufs");
 361
 362         channel_and_cpu = nth_token(recvbuf, 1);
 363         if(channel_and_cpu == NULL) {
 364                 ERR("cannot parse channel");
 365                 retval = -1;
 366                 goto end;
 367         }
 368
 369         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 370         if(ch_cpu == -1) {
 371                 ERR("problem parsing channel name");
 372                 retval = -1;
 373                 goto free_short_chan_name;
 374         }
 375
 376         ltt_lock_traces();
 377         trace = _ltt_trace_find(trace_name);
 378         ltt_unlock_traces();
 379
 380         if(trace == NULL) {
 381                 ERR("cannot find trace!");
 382                 retval = -1;
 383                 goto free_short_chan_name;
 384         }
 385
 386         for(i=0; i<trace->nr_channels; i++) {
 387                 struct ust_channel *channel = &trace->channels[i];
 388
 389                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 390                         char *reply;
 391
 392                         DBG("the n_subbufs for the requested channel is %d", channel->subbuf_cnt);
 393                         if (asprintf(&reply, "%d", channel->subbuf_cnt) < 0) {
 394                                 ERR("do_cmd_get_n_subbufs : asprintf failed (%d)",
 395                                     channel->subbuf_cnt);
 396                                 retval = -1;
 397                                 goto free_short_chan_name;
 398                         }
 399
 400                         result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
 401                         if(result) {
 402                                 ERR("ustcomm_send_reply failed");
 403                                 free(reply);
 404                                 retval = -1;
 405                                 goto free_short_chan_name;
 406                         }
 407
 408                         free(reply);
 409                         found = 1;
 410                         break;
 411                 }
 412         }
 413         if(found == 0) {
 414                 ERR("unable to find channel");
 415         }
 416
 417         free_short_chan_name:
 418         free(ch_name);
 419
 420         end:
 421         return retval;
 422 }
 423
 424 static int do_cmd_get_subbuf_size(const char *recvbuf, struct ustcomm_source *src)
 425 {
 426         int retval = 0;
 427         struct ust_trace *trace;
 428         char trace_name[] = "auto";
 429         int i;
 430         char *channel_and_cpu;
 431         int found = 0;
 432         int result;
 433         char *ch_name;
 434         int ch_cpu;
 435
 436         DBG("get_subbuf_size");
 437
 438         channel_and_cpu = nth_token(recvbuf, 1);
 439         if(channel_and_cpu == NULL) {
 440                 ERR("cannot parse channel");
 441                 retval = -1;
 442                 goto end;
 443         }
 444
 445         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 446         if(ch_cpu == -1) {
 447                 ERR("problem parsing channel name");
 448                 retval = -1;
 449                 goto free_short_chan_name;
 450         }
 451
 452         ltt_lock_traces();
 453         trace = _ltt_trace_find(trace_name);
 454         ltt_unlock_traces();
 455
 456         if(trace == NULL) {
 457                 ERR("cannot find trace!");
 458                 retval = -1;
 459                 goto free_short_chan_name;
 460         }
 461
 462         for(i=0; i<trace->nr_channels; i++) {
 463                 struct ust_channel *channel = &trace->channels[i];
 464
 465                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 466                         char *reply;
 467
 468                         DBG("the subbuf_size for the requested channel is %zd", channel->subbuf_size);
 469                         if (asprintf(&reply, "%zd", channel->subbuf_size) < 0) {
 470                                 ERR("do_cmd_get_subbuf_size : asprintf failed (%zd)",
 471                                     channel->subbuf_size);
 472                                 retval = -1;
 473                                 goto free_short_chan_name;
 474                         }
 475
 476                         result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
 477                         if(result) {
 478                                 ERR("ustcomm_send_reply failed");
 479                                 free(reply);
 480                                 retval = -1;
 481                                 goto free_short_chan_name;
 482                         }
 483
 484                         free(reply);
 485                         found = 1;
 486                         break;
 487                 }
 488         }
 489         if(found == 0) {
 490                 ERR("unable to find channel");
 491         }
 492
 493         free_short_chan_name:
 494         free(ch_name);
 495
 496         end:
 497         return retval;
 498 }
 499
 500 /* Return the power of two which is equal or higher to v */
 501
 502 static unsigned int pow2_higher_or_eq(unsigned int v)
 503 {
 504         int hb = fls(v);
 505         int retval = 1<<(hb-1);
 506
 507         if(v-retval == 0)
 508                 return retval;
 509         else
 510                 return retval<<1;
 511 }
 512
 513 static int do_cmd_set_subbuf_size(const char *recvbuf, struct ustcomm_source *src)
 514 {
 515         char *channel_slash_size;
 516         char ch_name[256]="";
 517         unsigned int size, power;
 518         int retval = 0;
 519         struct ust_trace *trace;
 520         char trace_name[] = "auto";
 521         int i;
 522         int found = 0;
 523
 524         DBG("set_subbuf_size");
 525
 526         channel_slash_size = nth_token(recvbuf, 1);
 527         sscanf(channel_slash_size, "%255[^/]/%u", ch_name, &size);
 528
 529         if(ch_name == NULL) {
 530                 ERR("cannot parse channel");
 531                 retval = -1;
 532                 goto end;
 533         }
 534
 535         power = pow2_higher_or_eq(size);
 536         power = max_t(unsigned int, 2u, power);
 537         if (power != size)
 538                 WARN("using the next power of two for buffer size = %u\n", power);
 539
 540         ltt_lock_traces();
 541         trace = _ltt_trace_find_setup(trace_name);
 542         if(trace == NULL) {
 543                 ERR("cannot find trace!");
 544                 retval = -1;
 545                 goto end;
 546         }
 547
 548         for(i = 0; i < trace->nr_channels; i++) {
 549                 struct ust_channel *channel = &trace->channels[i];
 550
 551                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 552
 553                         channel->subbuf_size = power;
 554                         DBG("the set_subbuf_size for the requested channel is %zd", channel->subbuf_size);
 555
 556                         found = 1;
 557                         break;
 558                 }
 559         }
 560         if(found == 0) {
 561                 ERR("unable to find channel");
 562         }
 563
 564         end:
 565         ltt_unlock_traces();
 566         return retval;
 567 }
 568
 569 static int do_cmd_set_subbuf_num(const char *recvbuf, struct ustcomm_source *src)
 570 {
 571         char *channel_slash_num;
 572         char ch_name[256]="";
 573         unsigned int num;
 574         int retval = 0;
 575         struct ust_trace *trace;
 576         char trace_name[] = "auto";
 577         int i;
 578         int found = 0;
 579
 580         DBG("set_subbuf_num");
 581
 582         channel_slash_num = nth_token(recvbuf, 1);
 583         sscanf(channel_slash_num, "%255[^/]/%u", ch_name, &num);
 584
 585         if(ch_name == NULL) {
 586                 ERR("cannot parse channel");
 587                 retval = -1;
 588                 goto end;
 589         }
 590         if (num < 2) {
 591                 ERR("subbuffer count should be greater than 2");
 592                 retval = -1;
 593                 goto end;
 594         }
 595
 596         ltt_lock_traces();
 597         trace = _ltt_trace_find_setup(trace_name);
 598         if(trace == NULL) {
 599                 ERR("cannot find trace!");
 600                 retval = -1;
 601                 goto end;
 602         }
 603
 604         for(i = 0; i < trace->nr_channels; i++) {
 605                 struct ust_channel *channel = &trace->channels[i];
 606
 607                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 608
 609                         channel->subbuf_cnt = num;
 610                         DBG("the set_subbuf_cnt for the requested channel is %zd", channel->subbuf_cnt);
 611
 612                         found = 1;
 613                         break;
 614                 }
 615         }
 616         if(found == 0) {
 617                 ERR("unable to find channel");
 618         }
 619
 620         end:
 621         ltt_unlock_traces();
 622         return retval;
 623 }
 624
 625 static int do_cmd_get_subbuffer(const char *recvbuf, struct ustcomm_source *src)
 626 {
 627         int retval = 0;
 628         struct ust_trace *trace;
 629         char trace_name[] = "auto";
 630         int i;
 631         char *channel_and_cpu;
 632         int found = 0;
 633         char *ch_name;
 634         int ch_cpu;
 635
 636         DBG("get_subbuf");
 637
 638         channel_and_cpu = nth_token(recvbuf, 1);
 639         if(channel_and_cpu == NULL) {
 640                 ERR("cannot parse channel");
 641                 retval = -1;
 642                 goto end;
 643         }
 644
 645         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 646         if(ch_cpu == -1) {
 647                 ERR("problem parsing channel name");
 648                 retval = -1;
 649                 goto free_short_chan_name;
 650         }
 651
 652         ltt_lock_traces();
 653         trace = _ltt_trace_find(trace_name);
 654
 655         if(trace == NULL) {
 656                 int result;
 657
 658                 DBG("Cannot find trace. It was likely destroyed by the user.");
 659                 result = ustcomm_send_reply(&ustcomm_app.server, "NOTFOUND", src);
 660                 if(result) {
 661                         ERR("ustcomm_send_reply failed");
 662                         retval = -1;
 663                         goto unlock_traces;
 664                 }
 665
 666                 goto unlock_traces;
 667         }
 668
 669         for(i=0; i<trace->nr_channels; i++) {
 670                 struct ust_channel *channel = &trace->channels[i];
 671
 672                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 673                         struct ust_buffer *buf = channel->buf[ch_cpu];
 674                         struct blocked_consumer *bc;
 675
 676                         found = 1;
 677
 678                         bc = (struct blocked_consumer *) malloc(sizeof(struct blocked_consumer));
 679                         if(bc == NULL) {
 680                                 ERR("malloc returned NULL");
 681                                 goto unlock_traces;
 682                         }
 683                         bc->fd_consumer = src->fd;
 684                         bc->fd_producer = buf->data_ready_fd_read;
 685                         bc->buf = buf;
 686                         bc->src = *src;
 687                         bc->server = ustcomm_app.server;
 688
 689                         list_add(&bc->list, &blocked_consumers);
 690
 691                         /* Being here is the proof the daemon has mapped the buffer in its
 692                          * memory. We may now decrement buffers_to_export.
 693                          */
 694                         if(uatomic_read(&buf->consumed) == 0) {
 695                                 DBG("decrementing buffers_to_export");
 696                                 STORE_SHARED(buffers_to_export, LOAD_SHARED(buffers_to_export)-1);
 697                         }
 698
 699                         break;
 700                 }
 701         }
 702         if(found == 0) {
 703                 ERR("unable to find channel");
 704         }
 705
 706         unlock_traces:
 707         ltt_unlock_traces();
 708
 709         free_short_chan_name:
 710         free(ch_name);
 711
 712         end:
 713         return retval;
 714 }
 715
 716 static int do_cmd_put_subbuffer(const char *recvbuf, struct ustcomm_source *src)
 717 {
 718         int retval = 0;
 719         struct ust_trace *trace;
 720         char trace_name[] = "auto";
 721         int i;
 722         char *channel_and_cpu;
 723         int found = 0;
 724         int result;
 725         char *ch_name;
 726         int ch_cpu;
 727         long consumed_old;
 728         char *consumed_old_str;
 729         char *endptr;
 730         char *reply = NULL;
 731
 732         DBG("put_subbuf");
 733
 734         channel_and_cpu = strdup(nth_token(recvbuf, 1));
 735         if(channel_and_cpu == NULL) {
 736                 ERR("cannot parse channel");
 737                 retval = -1;
 738                 goto end;
 739         }
 740
 741         consumed_old_str = strdup(nth_token(recvbuf, 2));
 742         if(consumed_old_str == NULL) {
 743                 ERR("cannot parse consumed_old");
 744                 retval = -1;
 745                 goto free_channel_and_cpu;
 746         }
 747         consumed_old = strtol(consumed_old_str, &endptr, 10);
 748         if(*endptr != '\0') {
 749                 ERR("invalid value for consumed_old");
 750                 retval = -1;
 751                 goto free_consumed_old_str;
 752         }
 753
 754         seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
 755         if(ch_cpu == -1) {
 756                 ERR("problem parsing channel name");
 757                 retval = -1;
 758                 goto free_short_chan_name;
 759         }
 760
 761         ltt_lock_traces();
 762         trace = _ltt_trace_find(trace_name);
 763
 764         if(trace == NULL) {
 765                 DBG("Cannot find trace. It was likely destroyed by the user.");
 766                 result = ustcomm_send_reply(&ustcomm_app.server, "NOTFOUND", src);
 767                 if(result) {
 768                         ERR("ustcomm_send_reply failed");
 769                         retval = -1;
 770                         goto unlock_traces;
 771                 }
 772
 773                 goto unlock_traces;
 774         }
 775
 776         for(i=0; i<trace->nr_channels; i++) {
 777                 struct ust_channel *channel = &trace->channels[i];
 778
 779                 if(!strcmp(trace->channels[i].channel_name, ch_name)) {
 780                         struct ust_buffer *buf = channel->buf[ch_cpu];
 781
 782                         found = 1;
 783
 784                         result = ust_buffers_put_subbuf(buf, consumed_old);
 785                         if(result < 0) {
 786                                 WARN("ust_buffers_put_subbuf: error (subbuf=%s)", channel_and_cpu);
 787                                 if (asprintf(&reply, "%s", "ERROR") < 0) {
 788                                         ERR("do_cmd_put_subbuffer : asprintf failed (ERROR)");
 789                                         retval = -1;
 790                                         goto unlock_traces;
 791                                 }
 792                         }
 793                         else {
 794                                 DBG("ust_buffers_put_subbuf: success (subbuf=%s)", channel_and_cpu);
 795                                 if (asprintf(&reply, "%s", "OK") < 0) {
 796                                         ERR("do_cmd_put_subbuffer : asprintf failed (OK)");
 797                                         retval = -1;
 798                                         goto unlock_traces;
 799                                 }
 800                         }
 801
 802                         result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
 803                         if(result) {
 804                                 ERR("ustcomm_send_reply failed");
 805                                 free(reply);
 806                                 retval = -1;
 807                                 goto unlock_traces;
 808                         }
 809
 810                         free(reply);
 811                         break;
 812                 }
 813         }
 814         if(found == 0) {
 815                 ERR("unable to find channel");
 816         }
 817
 818         unlock_traces:
 819         ltt_unlock_traces();
 820         free_short_chan_name:
 821         free(ch_name);
 822         free_consumed_old_str:
 823         free(consumed_old_str);
 824         free_channel_and_cpu:
 825         free(channel_and_cpu);
 826
 827         end:
 828         return retval;
 829 }
 830
 831 static void listener_cleanup(void *ptr)
 832 {
 833         ustcomm_fini_app(&ustcomm_app, 0);
 834 }
 835
 836 static void do_cmd_force_switch()
 837 {
 838         struct blocked_consumer *bc;
 839
 840         list_for_each_entry(bc, &blocked_consumers, list) {
 841                 ltt_force_switch(bc->buf, FORCE_FLUSH);
 842         }
 843 }
 844
 845 int process_client_cmd(char *recvbuf, struct ustcomm_source *src)
 846 {
 847         int result;
 848         char trace_name[] = "auto";
 849         char trace_type[] = "ustrelay";
 850         int len;
 851
 852         DBG("received a message! it's: %s", recvbuf);
 853         len = strlen(recvbuf);
 854
 855         if(!strcmp(recvbuf, "print_markers")) {
 856                 print_markers(stderr);
 857         }
 858         else if(!strcmp(recvbuf, "list_markers")) {
 859                 char *ptr;
 860                 size_t size;
 861                 FILE *fp;
 862
 863                 fp = open_memstream(&ptr, &size);
 864                 print_markers(fp);
 865                 fclose(fp);
 866
 867                 result = ustcomm_send_reply(&ustcomm_app.server, ptr, src);
 868
 869                 free(ptr);
 870         }
 871         else if(!strcmp(recvbuf, "start")) {
 872                 /* start is an operation that setups the trace, allocates it and starts it */
 873                 result = ltt_trace_setup(trace_name);
 874                 if(result < 0) {
 875                         ERR("ltt_trace_setup failed");
 876                         return -1;
 877                 }
 878
 879                 result = ltt_trace_set_type(trace_name, trace_type);
 880                 if(result < 0) {
 881                         ERR("ltt_trace_set_type failed");
 882                         return -1;
 883                 }
 884
 885                 result = ltt_trace_alloc(trace_name);
 886                 if(result < 0) {
 887                         ERR("ltt_trace_alloc failed");
 888                         return -1;
 889                 }
 890
 891                 inform_consumer_daemon(trace_name);
 892
 893                 result = ltt_trace_start(trace_name);
 894                 if(result < 0) {
 895                         ERR("ltt_trace_start failed");
 896                         return -1;
 897                 }
 898         }
 899         else if(!strcmp(recvbuf, "trace_setup")) {
 900                 DBG("trace setup");
 901
 902                 result = ltt_trace_setup(trace_name);
 903                 if(result < 0) {
 904                         ERR("ltt_trace_setup failed");
 905                         return -1;
 906                 }
 907
 908                 result = ltt_trace_set_type(trace_name, trace_type);
 909                 if(result < 0) {
 910                         ERR("ltt_trace_set_type failed");
 911                         return -1;
 912                 }
 913         }
 914         else if(!strcmp(recvbuf, "trace_alloc")) {
 915                 DBG("trace alloc");
 916
 917                 result = ltt_trace_alloc(trace_name);
 918                 if(result < 0) {
 919                         ERR("ltt_trace_alloc failed");
 920                         return -1;
 921                 }
 922                 inform_consumer_daemon(trace_name);
 923         }
 924         else if(!strcmp(recvbuf, "trace_create")) {
 925                 DBG("trace create");
 926
 927                 result = ltt_trace_setup(trace_name);
 928                 if(result < 0) {
 929                         ERR("ltt_trace_setup failed");
 930                         return -1;
 931                 }
 932
 933                 result = ltt_trace_set_type(trace_name, trace_type);
 934                 if(result < 0) {
 935                         ERR("ltt_trace_set_type failed");
 936                         return -1;
 937                 }
 938         }
 939         else if(!strcmp(recvbuf, "trace_start")) {
 940                 DBG("trace start");
 941
 942                 result = ltt_trace_alloc(trace_name);
 943                 if(result < 0) {
 944                         ERR("ltt_trace_alloc failed");
 945                         return -1;
 946                 }
 947                 if(!result) {
 948                         inform_consumer_daemon(trace_name);
 949                 }
 950
 951                 result = ltt_trace_start(trace_name);
 952                 if(result < 0) {
 953                         ERR("ltt_trace_start failed");
 954                         return -1;
 955                 }
 956         }
 957         else if(!strcmp(recvbuf, "trace_stop")) {
 958                 DBG("trace stop");
 959
 960                 result = ltt_trace_stop(trace_name);
 961                 if(result < 0) {
 962                         ERR("ltt_trace_stop failed");
 963                         return -1;
 964                 }
 965         }
 966         else if(!strcmp(recvbuf, "trace_destroy")) {
 967
 968                 DBG("trace destroy");
 969
 970                 result = ltt_trace_destroy(trace_name, 0);
 971                 if(result < 0) {
 972                         ERR("ltt_trace_destroy failed");
 973                         return -1;
 974                 }
 975         }
 976         else if(nth_token_is(recvbuf, "get_shmid", 0) == 1) {
 977                 do_cmd_get_shmid(recvbuf, src);
 978         }
 979         else if(nth_token_is(recvbuf, "get_n_subbufs", 0) == 1) {
 980                 do_cmd_get_n_subbufs(recvbuf, src);
 981         }
 982         else if(nth_token_is(recvbuf, "get_subbuf_size", 0) == 1) {
 983                 do_cmd_get_subbuf_size(recvbuf, src);
 984         }
 985         else if(nth_token_is(recvbuf, "load_probe_lib", 0) == 1) {
 986                 char *libfile;
 987
 988                 libfile = nth_token(recvbuf, 1);
 989
 990                 DBG("load_probe_lib loading %s", libfile);
 991
 992                 free(libfile);
 993         }
 994         else if(nth_token_is(recvbuf, "get_subbuffer", 0) == 1) {
 995                 do_cmd_get_subbuffer(recvbuf, src);
 996         }
 997         else if(nth_token_is(recvbuf, "put_subbuffer", 0) == 1) {
 998                 do_cmd_put_subbuffer(recvbuf, src);
 999         }
1000         else if(nth_token_is(recvbuf, "set_subbuf_size", 0) == 1) {
1001                 do_cmd_set_subbuf_size(recvbuf, src);
1002         }
1003         else if(nth_token_is(recvbuf, "set_subbuf_num", 0) == 1) {
1004                 do_cmd_set_subbuf_num(recvbuf, src);
1005         }
1006         else if(nth_token_is(recvbuf, "enable_marker", 0) == 1) {
1007                 char *channel_slash_name = nth_token(recvbuf, 1);
1008                 char channel_name[256]="";
1009                 char marker_name[256]="";
1010
1011                 result = sscanf(channel_slash_name, "%255[^/]/%255s", channel_name, marker_name);
1012
1013                 if(channel_name == NULL || marker_name == NULL) {
1014                         WARN("invalid marker name");
1015                         goto next_cmd;
1016                 }
1017
1018                 result = ltt_marker_connect(channel_name, marker_name, "default");
1019                 if(result < 0) {
1020                         WARN("could not enable marker; channel=%s, name=%s", channel_name, marker_name);
1021                 }
1022         }
1023         else if(nth_token_is(recvbuf, "disable_marker", 0) == 1) {
1024                 char *channel_slash_name = nth_token(recvbuf, 1);
1025                 char *marker_name;
1026                 char *channel_name;
1027
1028                 result = sscanf(channel_slash_name, "%a[^/]/%as", &channel_name, &marker_name);
1029
1030                 if(marker_name == NULL) {
1031                 }
1032
1033                 result = ltt_marker_disconnect(channel_name, marker_name, "default");
1034                 if(result < 0) {
1035                         WARN("could not disable marker; channel=%s, name=%s", channel_name, marker_name);
1036                 }
1037         }
1038         else if(nth_token_is(recvbuf, "get_pidunique", 0) == 1) {
1039                 char *reply;
1040
1041                 if (asprintf(&reply, "%lld", pidunique) < 0) {
1042                         ERR("process_client_cmd : asprintf failed (%lld)",
1043                             pidunique);
1044                         goto next_cmd;
1045                 }
1046
1047                 result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
1048                 if(result) {
1049                         ERR("listener: get_pidunique: ustcomm_send_reply failed");
1050                         goto next_cmd;
1051                 }
1052
1053                 free(reply);
1054         }
1055         else if(nth_token_is(recvbuf, "get_sock_path", 0) == 1) {
1056                 char *reply = getenv("UST_DAEMON_SOCKET");
1057                 if(!reply) {
1058                         if (asprintf(&reply, "%s/%s", SOCK_DIR, "ustd") < 0) {
1059                                 ERR("process_client_cmd : asprintf failed (%s/ustd)",
1060                                     SOCK_DIR);
1061                                 goto next_cmd;
1062                         }
1063                         result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
1064                         free(reply);
1065                 }
1066                 else {
1067                         result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
1068                 }
1069                 if(result)
1070                         ERR("ustcomm_send_reply failed");
1071         }
1072         else if(nth_token_is(recvbuf, "set_sock_path", 0) == 1) {
1073                 char *sock_path = nth_token(recvbuf, 1);
1074                 result = setenv("UST_DAEMON_SOCKET", sock_path, 1);
1075                 if(result)
1076                         ERR("cannot set UST_DAEMON_SOCKET environment variable");
1077         }
1078         else if(nth_token_is(recvbuf, "force_switch", 0) == 1) {
1079                 do_cmd_force_switch();
1080         }
1081         else {
1082                 ERR("unable to parse message: %s", recvbuf);
1083         }
1084
1085 next_cmd:
1086
1087         return 0;
1088 }
1089
1090 void *listener_main(void *p)
1091 {
1092         int result;
1093
1094         DBG("LISTENER");
1095
1096         pthread_cleanup_push(listener_cleanup, NULL);
1097
1098         for(;;) {
1099                 struct mpentries mpent;
1100
1101                 multipoll_init(&mpent);
1102
1103                 blocked_consumers_add_to_mp(&mpent);
1104                 ustcomm_mp_add_app_clients(&mpent, &ustcomm_app, process_client_cmd);
1105
1106                 result = multipoll_poll(&mpent, -1);
1107                 if(result == -1) {
1108                         ERR("error in multipoll_poll");
1109                 }
1110
1111                 multipoll_destroy(&mpent);
1112         }
1113
1114         pthread_cleanup_pop(1);
1115 }
1116
1117 /* These should only be accessed in the parent thread,
1118  * not the listener.
1119  */
1120 static volatile sig_atomic_t have_listener = 0;
1121 static pthread_t listener_thread;
1122
1123 void create_listener(void)
1124 {
1125         int result;
1126         sigset_t sig_all_blocked;
1127         sigset_t orig_parent_mask;
1128
1129         if(have_listener) {
1130                 WARN("not creating listener because we already had one");
1131                 return;
1132         }
1133
1134         /* A new thread created by pthread_create inherits the signal mask
1135          * from the parent. To avoid any signal being received by the
1136          * listener thread, we block all signals temporarily in the parent,
1137          * while we create the listener thread.
1138          */
1139
1140         sigfillset(&sig_all_blocked);
1141
1142         result = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
1143         if(result) {
1144                 PERROR("pthread_sigmask: %s", strerror(result));
1145         }
1146
1147         result = pthread_create(&listener_thread, NULL, listener_main, NULL);
1148         if(result == -1) {
1149                 PERROR("pthread_create");
1150         }
1151
1152         /* Restore original signal mask in parent */
1153         result = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
1154         if(result) {
1155                 PERROR("pthread_sigmask: %s", strerror(result));
1156         }
1157         else {
1158                 have_listener = 1;
1159         }
1160 }
1161
1162 static int init_socket(void)
1163 {
1164         return ustcomm_init_app(getpid(), &ustcomm_app);
1165 }
1166
1167 #define AUTOPROBE_DISABLED      0
1168 #define AUTOPROBE_ENABLE_ALL    1
1169 #define AUTOPROBE_ENABLE_REGEX  2
1170 static int autoprobe_method = AUTOPROBE_DISABLED;
1171 static regex_t autoprobe_regex;
1172
1173 static void auto_probe_connect(struct marker *m)
1174 {
1175         int result;
1176
1177         char* concat_name = NULL;
1178         const char *probe_name = "default";
1179
1180         if(autoprobe_method == AUTOPROBE_DISABLED) {
1181                 return;
1182         }
1183         else if(autoprobe_method == AUTOPROBE_ENABLE_REGEX) {
1184                 result = asprintf(&concat_name, "%s/%s", m->channel, m->name);
1185                 if(result == -1) {
1186                         ERR("auto_probe_connect: asprintf failed (marker %s/%s)",
1187                                 m->channel, m->name);
1188                         return;
1189                 }
1190                 if (regexec(&autoprobe_regex, concat_name, 0, NULL, 0)) {
1191                         free(concat_name);
1192                         return;
1193                 }
1194                 free(concat_name);
1195         }
1196
1197         result = ltt_marker_connect(m->channel, m->name, probe_name);
1198         if(result && result != -EEXIST)
1199                 ERR("ltt_marker_connect (marker = %s/%s, errno = %d)", m->channel, m->name, -result);
1200
1201         DBG("auto connected marker %s (addr: %p) %s to probe default", m->channel, m, m->name);
1202
1203 }
1204
1205 static void __attribute__((constructor)) init()
1206 {
1207         int result;
1208         char* autoprobe_val = NULL;
1209         char* subbuffer_size_val = NULL;
1210         char* subbuffer_count_val = NULL;
1211         unsigned int subbuffer_size;
1212         unsigned int subbuffer_count;
1213         unsigned int power;
1214
1215         /* Assign the pidunique, to be able to differentiate the processes with same
1216          * pid, (before and after an exec).
1217          */
1218         pidunique = make_pidunique();
1219
1220         DBG("Tracectl constructor");
1221
1222         result = init_socket();
1223         if(result == -1) {
1224                 ERR("init_socket error");
1225                 return;
1226         }
1227
1228         create_listener();
1229
1230         autoprobe_val = getenv("UST_AUTOPROBE");
1231         if(autoprobe_val) {
1232                 struct marker_iter iter;
1233
1234                 DBG("Autoprobe enabled.");
1235
1236                 /* Ensure markers are initialized */
1237                 //init_markers();
1238
1239                 /* Ensure marker control is initialized, for the probe */
1240                 init_marker_control();
1241
1242                 /* first, set the callback that will connect the
1243                  * probe on new markers
1244                  */
1245                 if(autoprobe_val[0] == '/') {
1246                         result = regcomp(&autoprobe_regex, autoprobe_val+1, 0);
1247                         if (result) {
1248                                 char regexerr[150];
1249
1250                                 regerror(result, &autoprobe_regex, regexerr, sizeof(regexerr));
1251                                 ERR("cannot parse regex %s (%s), will ignore UST_AUTOPROBE", autoprobe_val, regexerr);
1252                                 /* don't crash the application just for this */
1253                         }
1254                         else {
1255                                 autoprobe_method = AUTOPROBE_ENABLE_REGEX;
1256                         }
1257                 }
1258                 else {
1259                         /* just enable all instrumentation */
1260                         autoprobe_method = AUTOPROBE_ENABLE_ALL;
1261                 }
1262
1263                 marker_set_new_marker_cb(auto_probe_connect);
1264
1265                 /* Now, connect the probes that were already registered. */
1266                 marker_iter_reset(&iter);
1267                 marker_iter_start(&iter);
1268
1269                 DBG("now iterating on markers already registered");
1270                 while(iter.marker) {
1271                         DBG("now iterating on marker %s", iter.marker->name);
1272                         auto_probe_connect(iter.marker);
1273                         marker_iter_next(&iter);
1274                 }
1275         }
1276
1277         if(getenv("UST_OVERWRITE")) {
1278                 int val = atoi(getenv("UST_OVERWRITE"));
1279                 if(val == 0 || val == 1) {
1280                         STORE_SHARED(ust_channels_overwrite_by_default, val);
1281                 }
1282                 else {
1283                         WARN("invalid value for UST_OVERWRITE");
1284                 }
1285         }
1286
1287         if(getenv("UST_AUTOCOLLECT")) {
1288                 int val = atoi(getenv("UST_AUTOCOLLECT"));
1289                 if(val == 0 || val == 1) {
1290                         STORE_SHARED(ust_channels_request_collection_by_default, val);
1291                 }
1292                 else {
1293                         WARN("invalid value for UST_AUTOCOLLECT");
1294                 }
1295         }
1296
1297         subbuffer_size_val = getenv("UST_SUBBUF_SIZE");
1298         if(subbuffer_size_val) {
1299                 sscanf(subbuffer_size_val, "%u", &subbuffer_size);
1300                 power = pow2_higher_or_eq(subbuffer_size);
1301                 if(power != subbuffer_size)
1302                         WARN("using the next power of two for buffer size = %u\n", power);
1303                 chan_infos[LTT_CHANNEL_UST].def_subbufsize = power;
1304         }
1305
1306         subbuffer_count_val = getenv("UST_SUBBUF_NUM");
1307         if(subbuffer_count_val) {
1308                 sscanf(subbuffer_count_val, "%u", &subbuffer_count);
1309                 if(subbuffer_count < 2)
1310                         subbuffer_count = 2;
1311                 chan_infos[LTT_CHANNEL_UST].def_subbufcount = subbuffer_count;
1312         }
1313
1314         if(getenv("UST_TRACE")) {
1315                 char trace_name[] = "auto";
1316                 char trace_type[] = "ustrelay";
1317
1318                 DBG("starting early tracing");
1319
1320                 /* Ensure marker control is initialized */
1321                 init_marker_control();
1322
1323                 /* Ensure markers are initialized */
1324                 init_markers();
1325
1326                 /* Ensure buffers are initialized, for the transport to be available.
1327                  * We are about to set a trace type and it will fail without this.
1328                  */
1329                 init_ustrelay_transport();
1330
1331                 /* FIXME: When starting early tracing (here), depending on the
1332                  * order of constructors, it is very well possible some marker
1333                  * sections are not yet registered. Because of this, some
1334                  * channels may not be registered. Yet, we are about to ask the
1335                  * daemon to collect the channels. Channels which are not yet
1336                  * registered will not be collected.
1337                  *
1338                  * Currently, in LTTng, there is no way to add a channel after
1339                  * trace start. The reason for this is that it induces complex
1340                  * concurrency issues on the trace structures, which can only
1341                  * be resolved using RCU. This has not been done yet. As a
1342                  * workaround, we are forcing the registration of the "ust"
1343                  * channel here. This is the only channel (apart from metadata)
1344                  * that can be reliably used in early tracing.
1345                  *
1346                  * Non-early tracing does not have this problem and can use
1347                  * arbitrary channel names.
1348                  */
1349                 ltt_channels_register("ust");
1350
1351                 result = ltt_trace_setup(trace_name);
1352                 if(result < 0) {
1353                         ERR("ltt_trace_setup failed");
1354                         return;
1355                 }
1356
1357                 result = ltt_trace_set_type(trace_name, trace_type);
1358                 if(result < 0) {
1359                         ERR("ltt_trace_set_type failed");
1360                         return;
1361                 }
1362
1363                 result = ltt_trace_alloc(trace_name);
1364                 if(result < 0) {
1365                         ERR("ltt_trace_alloc failed");
1366                         return;
1367                 }
1368
1369                 result = ltt_trace_start(trace_name);
1370                 if(result < 0) {
1371                         ERR("ltt_trace_start failed");
1372                         return;
1373                 }
1374
1375                 /* Do this after the trace is started in order to avoid creating confusion
1376                  * if the trace fails to start. */
1377                 inform_consumer_daemon(trace_name);
1378         }
1379
1380         return;
1381
1382         /* should decrementally destroy stuff if error */
1383
1384 }
1385
1386 /* This is only called if we terminate normally, not with an unhandled signal,
1387  * so we cannot rely on it. However, for now, LTTV requires that the header of
1388  * the last sub-buffer contain a valid end time for the trace. This is done
1389  * automatically only when the trace is properly stopped.
1390  *
1391  * If the traced program crashed, it is always possible to manually add the
1392  * right value in the header, or to open the trace in text mode.
1393  *
1394  * FIXME: Fix LTTV so it doesn't need this.
1395  */
1396
1397 static void destroy_traces(void)
1398 {
1399         int result;
1400
1401         /* if trace running, finish it */
1402
1403         DBG("destructor stopping traces");
1404
1405         result = ltt_trace_stop("auto");
1406         if(result == -1) {
1407                 ERR("ltt_trace_stop error");
1408         }
1409
1410         result = ltt_trace_destroy("auto", 0);
1411         if(result == -1) {
1412                 ERR("ltt_trace_destroy error");
1413         }
1414 }
1415
1416 static int trace_recording(void)
1417 {
1418         int retval = 0;
1419         struct ust_trace *trace;
1420
1421         ltt_lock_traces();
1422
1423         list_for_each_entry(trace, &ltt_traces.head, list) {
1424                 if(trace->active) {
1425                         retval = 1;
1426                         break;
1427                 }
1428         }
1429
1430         ltt_unlock_traces();
1431
1432         return retval;
1433 }
1434
1435 #if 0
1436 static int have_consumer(void)
1437 {
1438         return !list_empty(&blocked_consumers);
1439 }
1440 #endif
1441
1442 int restarting_usleep(useconds_t usecs)
1443 {
1444         struct timespec tv;
1445         int result;
1446
1447         tv.tv_sec = 0;
1448         tv.tv_nsec = usecs * 1000;
1449
1450         do {
1451                 result = nanosleep(&tv, &tv);
1452         } while(result == -1 && errno == EINTR);
1453
1454         return result;
1455 }
1456
1457 static void stop_listener(void)
1458 {
1459         int result;
1460
1461         if(!have_listener)
1462                 return;
1463
1464         result = pthread_cancel(listener_thread);
1465         if(result != 0) {
1466                 ERR("pthread_cancel: %s", strerror(result));
1467         }
1468         result = pthread_join(listener_thread, NULL);
1469         if(result != 0) {
1470                 ERR("pthread_join: %s", strerror(result));
1471         }
1472 }
1473
1474 /* This destructor keeps the process alive for a few seconds in order
1475  * to leave time to ustd to connect to its buffers. This is necessary
1476  * for programs whose execution is very short. It is also useful in all
1477  * programs when tracing is started close to the end of the program
1478  * execution.
1479  *
1480  * FIXME: For now, this only works for the first trace created in a
1481  * process.
1482  */
1483
1484 static void __attribute__((destructor)) keepalive()
1485 {
1486         if(trace_recording() && LOAD_SHARED(buffers_to_export)) {
1487                 int total = 0;
1488                 DBG("Keeping process alive for consumer daemon...");
1489                 while(LOAD_SHARED(buffers_to_export)) {
1490                         const int interv = 200000;
1491                         restarting_usleep(interv);
1492                         total += interv;
1493
1494                         if(total >= 3000000) {
1495                                 WARN("non-consumed buffers remaining after wait limit; not waiting anymore");
1496                                 break;
1497                         }
1498                 }
1499                 DBG("Finally dying...");
1500         }
1501
1502         destroy_traces();
1503
1504         /* Ask the listener to stop and clean up. */
1505         stop_listener();
1506 }
1507
1508 void ust_potential_exec(void)
1509 {
1510         trace_mark(ust, potential_exec, MARK_NOARGS);
1511
1512         DBG("test");
1513
1514         keepalive();
1515 }
1516
1517 /* Notify ust that there was a fork. This needs to be called inside
1518  * the new process, anytime a process whose memory is not shared with
1519  * the parent is created. If this function is not called, the events
1520  * of the new process will not be collected.
1521  *
1522  * Signals should be disabled before the fork and reenabled only after
1523  * this call in order to guarantee tracing is not started before ust_fork()
1524  * sanitizes the new process.
1525  */
1526
1527 static void ust_fork(void)
1528 {
1529         struct blocked_consumer *bc;
1530         struct blocked_consumer *deletable_bc = NULL;
1531         int result;
1532
1533         /* FIXME: technically, the locks could have been taken before the fork */
1534         DBG("ust: forking");
1535
1536         /* break lock if necessary */
1537         ltt_unlock_traces();
1538
1539         ltt_trace_stop("auto");
1540         ltt_trace_destroy("auto", 1);
1541         /* Delete all active connections */
1542         ustcomm_close_all_connections(&ustcomm_app.server);
1543
1544         /* Delete all blocked consumers */
1545         list_for_each_entry(bc, &blocked_consumers, list) {
1546                 result = close(bc->fd_producer);
1547                 if(result == -1) {
1548                         PERROR("close");
1549                 }
1550                 free(deletable_bc);
1551                 deletable_bc = bc;
1552                 list_del(&bc->list);
1553         }
1554
1555         /* free app, keeping socket file */
1556         ustcomm_fini_app(&ustcomm_app, 1);
1557
1558         STORE_SHARED(buffers_to_export, 0);
1559         have_listener = 0;
1560         init_socket();
1561         create_listener();
1562         ltt_trace_setup("auto");
1563         result = ltt_trace_set_type("auto", "ustrelay");
1564         if(result < 0) {
1565                 ERR("ltt_trace_set_type failed");
1566                 return;
1567         }
1568
1569         ltt_trace_alloc("auto");
1570         ltt_trace_start("auto");
1571         inform_consumer_daemon("auto");
1572 }
1573
1574 void ust_before_fork(ust_fork_info_t *fork_info)
1575 {
1576         /* Disable signals. This is to avoid that the child
1577          * intervenes before it is properly setup for tracing. It is
1578          * safer to disable all signals, because then we know we are not
1579          * breaking anything by restoring the original mask.
1580          */
1581         sigset_t all_sigs;
1582         int result;
1583
1584         /* FIXME:
1585                 - only do this if tracing is active
1586         */
1587
1588         /* Disable signals */
1589         sigfillset(&all_sigs);
1590         result = sigprocmask(SIG_BLOCK, &all_sigs, &fork_info->orig_sigs);
1591         if(result == -1) {
1592                 PERROR("sigprocmask");
1593                 return;
1594         }
1595 }
1596
1597 /* Don't call this function directly in a traced program */
1598 static void ust_after_fork_common(ust_fork_info_t *fork_info)
1599 {
1600         int result;
1601
1602         /* Restore signals */
1603         result = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL);
1604         if(result == -1) {
1605                 PERROR("sigprocmask");
1606                 return;
1607         }
1608 }
1609
1610 void ust_after_fork_parent(ust_fork_info_t *fork_info)
1611 {
1612         /* Reenable signals */
1613         ust_after_fork_common(fork_info);
1614 }
1615
1616 void ust_after_fork_child(ust_fork_info_t *fork_info)
1617 {
1618         /* First sanitize the child */
1619         ust_fork();
1620
1621         /* Then reenable interrupts */
1622         ust_after_fork_common(fork_info);
1623 }
1624