libustconsumer/libustconsumer.c

   1 /* Copyright (C) 2009  Pierre-Marc Fournier
   2  *               2010  Alexis Halle
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  17  */
  18
  19 #define _GNU_SOURCE
  20
  21 #include <sys/epoll.h>
  22 #include <sys/shm.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <unistd.h>
  26 #include <pthread.h>
  27 #include <signal.h>
  28
  29 #include <stdlib.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <errno.h>
  33 #include <assert.h>
  34
  35 #include <ust/ustconsumer.h>
  36 #include "lowlevel.h"
  37 #include "usterr.h"
  38 #include "ustcomm.h"
  39
  40 #define GET_SUBBUF_OK 1
  41 #define GET_SUBBUF_DONE 0
  42 #define GET_SUBBUF_DIED 2
  43
  44 #define PUT_SUBBUF_OK 1
  45 #define PUT_SUBBUF_DIED 0
  46 #define PUT_SUBBUF_PUSHED 2
  47 #define PUT_SUBBUF_DONE 3
  48
  49 #define UNIX_PATH_MAX 108
  50
  51 static int get_subbuffer(struct buffer_info *buf)
  52 {
  53         struct ustcomm_header _send_hdr, *send_hdr;
  54         struct ustcomm_header _recv_hdr, *recv_hdr;
  55         struct ustcomm_buffer_info _send_msg, _recv_msg;
  56         struct ustcomm_buffer_info *send_msg, *recv_msg;
  57         int result;
  58
  59         send_hdr = &_send_hdr;
  60         recv_hdr = &_recv_hdr;
  61         send_msg = &_send_msg;
  62         recv_msg = &_recv_msg;
  63
  64         result = ustcomm_pack_buffer_info(send_hdr, send_msg, buf->trace,
  65                                           buf->channel, buf->channel_cpu);
  66         if (result < 0) {
  67                 return result;
  68         }
  69
  70         send_hdr->command = GET_SUBBUFFER;
  71
  72         result = ustcomm_req(buf->app_sock, send_hdr, (char *)send_msg,
  73                              recv_hdr, (char *)recv_msg);
  74         if ((result < 0 && (errno == ECONNRESET || errno == EPIPE)) ||
  75             result == 0) {
  76                 DBG("app died while being traced");
  77                 return GET_SUBBUF_DIED;
  78         } else if (result < 0) {
  79                 ERR("get_subbuffer: ustcomm_req failed");
  80                 return result;
  81         }
  82
  83         if (!recv_hdr->result) {
  84                 DBG("got subbuffer %s", buf->name);
  85                 buf->consumed_old = recv_msg->consumed_old;
  86                 return GET_SUBBUF_OK;
  87         } else if (recv_hdr->result == -ENODATA) {
  88                 DBG("For buffer %s, the trace was not found. This likely means"
  89                     " it was destroyed by the user.", buf->name);
  90                 return GET_SUBBUF_DIED;
  91         }
  92
  93         DBG("error getting subbuffer %s", buf->name);
  94         return recv_hdr->result;
  95 }
  96
  97 static int put_subbuffer(struct buffer_info *buf)
  98 {
  99         struct ustcomm_header _send_hdr, *send_hdr;
 100         struct ustcomm_header _recv_hdr, *recv_hdr;
 101         struct ustcomm_buffer_info _send_msg, *send_msg;
 102         int result;
 103
 104         send_hdr = &_send_hdr;
 105         recv_hdr = &_recv_hdr;
 106         send_msg = &_send_msg;
 107
 108         result = ustcomm_pack_buffer_info(send_hdr, send_msg, buf->trace,
 109                                           buf->channel, buf->channel_cpu);
 110         if (result < 0) {
 111                 return result;
 112         }
 113
 114         send_hdr->command = PUT_SUBBUFFER;
 115         send_msg->consumed_old = buf->consumed_old;
 116
 117         result = ustcomm_req(buf->app_sock, send_hdr, (char *)send_msg,
 118                              recv_hdr, NULL);
 119         if ((result < 0 && (errno == ECONNRESET || errno == EPIPE)) ||
 120             result == 0) {
 121                 DBG("app died while being traced");
 122                 return PUT_SUBBUF_DIED;
 123         } else if (result < 0) {
 124                 ERR("put_subbuffer: ustcomm_req failed");
 125                 return result;
 126         }
 127
 128         if (!recv_hdr->result) {
 129                 DBG("put subbuffer %s", buf->name);
 130                 return PUT_SUBBUF_OK;
 131         } else if (recv_hdr->result == -ENODATA) {
 132                 DBG("For buffer %s, the trace was not found. This likely means"
 133                     " it was destroyed by the user.", buf->name);
 134                 return PUT_SUBBUF_DIED;
 135         }
 136
 137         DBG("error getting subbuffer %s", buf->name);
 138         return recv_hdr->result;
 139 }
 140
 141 void decrement_active_buffers(void *arg)
 142 {
 143         struct ustconsumer_instance *instance = arg;
 144         pthread_mutex_lock(&instance->mutex);
 145         instance->active_buffers--;
 146         pthread_mutex_unlock(&instance->mutex);
 147 }
 148
 149 static int get_pidunique(int sock, s64 *pidunique)
 150 {
 151         struct ustcomm_header _send_hdr, *send_hdr;
 152         struct ustcomm_header _recv_hdr, *recv_hdr;
 153         struct ustcomm_pidunique _recv_msg, *recv_msg;
 154         int result;
 155
 156         send_hdr = &_send_hdr;
 157         recv_hdr = &_recv_hdr;
 158         recv_msg = &_recv_msg;
 159
 160         memset(send_hdr, 0, sizeof(*send_hdr));
 161
 162         send_hdr->command = GET_PIDUNIQUE;
 163         result = ustcomm_req(sock, send_hdr, NULL, recv_hdr, (char *)recv_msg);
 164         if (result < 1) {
 165                 return -ENOTCONN;
 166         }
 167         if (recv_hdr->result < 0) {
 168                 ERR("App responded with error: %s", strerror(recv_hdr->result));
 169                 return recv_hdr->result;
 170         }
 171
 172         *pidunique = recv_msg->pidunique;
 173
 174         return 0;
 175 }
 176
 177 static int get_buf_shmid_pipe_fd(int sock, struct buffer_info *buf,
 178                                  int *buf_shmid, int *buf_struct_shmid,
 179                                  int *buf_pipe_fd)
 180 {
 181         struct ustcomm_header _send_hdr, *send_hdr;
 182         struct ustcomm_header _recv_hdr, *recv_hdr;
 183         struct ustcomm_buffer_info _send_msg, *send_msg;
 184         struct ustcomm_buffer_info _recv_msg, *recv_msg;
 185         int result, recv_pipe_fd;
 186
 187         send_hdr = &_send_hdr;
 188         recv_hdr = &_recv_hdr;
 189         send_msg = &_send_msg;
 190         recv_msg = &_recv_msg;
 191
 192         result = ustcomm_pack_buffer_info(send_hdr, send_msg, buf->trace,
 193                                           buf->channel, buf->channel_cpu);
 194         if (result < 0) {
 195                 ERR("Failed to pack buffer info");
 196                 return result;
 197         }
 198
 199         send_hdr->command = GET_BUF_SHMID_PIPE_FD;
 200
 201         result = ustcomm_send(sock, send_hdr, (char *)send_msg);
 202         if (result < 1) {
 203                 ERR("Failed to send request");
 204                 return -ENOTCONN;
 205         }
 206         result = ustcomm_recv_fd(sock, recv_hdr, (char *)recv_msg, &recv_pipe_fd);
 207         if (result < 1) {
 208                 ERR("Failed to receive message and fd");
 209                 return -ENOTCONN;
 210         }
 211         if (recv_hdr->result < 0) {
 212                 ERR("App responded with error %s", strerror(recv_hdr->result));
 213                 return recv_hdr->result;
 214         }
 215
 216         *buf_shmid = recv_msg->buf_shmid;
 217         *buf_struct_shmid = recv_msg->buf_struct_shmid;
 218         *buf_pipe_fd = recv_pipe_fd;
 219
 220         return 0;
 221 }
 222
 223 static int get_subbuf_num_size(int sock, struct buffer_info *buf,
 224                                int *subbuf_num, int *subbuf_size)
 225 {
 226         struct ustcomm_header _send_hdr, *send_hdr;
 227         struct ustcomm_header _recv_hdr, *recv_hdr;
 228         struct ustcomm_channel_info _send_msg, *send_msg;
 229         struct ustcomm_channel_info _recv_msg, *recv_msg;
 230         int result;
 231
 232         send_hdr = &_send_hdr;
 233         recv_hdr = &_recv_hdr;
 234         send_msg = &_send_msg;
 235         recv_msg = &_recv_msg;
 236
 237         result = ustcomm_pack_channel_info(send_hdr, send_msg, buf->trace,
 238                                            buf->channel);
 239         if (result < 0) {
 240                 return result;
 241         }
 242
 243         send_hdr->command = GET_SUBBUF_NUM_SIZE;
 244
 245         result = ustcomm_req(sock, send_hdr, (char *)send_msg,
 246                              recv_hdr, (char *)recv_msg);
 247         if (result < 1) {
 248                 return -ENOTCONN;
 249         }
 250
 251         *subbuf_num = recv_msg->subbuf_num;
 252         *subbuf_size = recv_msg->subbuf_size;
 253
 254         return recv_hdr->result;
 255 }
 256
 257
 258 static int notify_buffer_mapped(int sock, struct buffer_info *buf)
 259 {
 260         struct ustcomm_header _send_hdr, *send_hdr;
 261         struct ustcomm_header _recv_hdr, *recv_hdr;
 262         struct ustcomm_buffer_info _send_msg, *send_msg;
 263         int result;
 264
 265         send_hdr = &_send_hdr;
 266         recv_hdr = &_recv_hdr;
 267         send_msg = &_send_msg;
 268
 269         result = ustcomm_pack_buffer_info(send_hdr, send_msg, buf->trace,
 270                                           buf->channel, buf->channel_cpu);
 271         if (result < 0) {
 272                 return result;
 273         }
 274
 275         send_hdr->command = NOTIFY_BUF_MAPPED;
 276
 277         result = ustcomm_req(sock, send_hdr, (char *)send_msg,
 278                              recv_hdr, NULL);
 279         if (result < 1) {
 280                 return -ENOTCONN;
 281         }
 282
 283         return recv_hdr->result;
 284 }
 285
 286
 287 struct buffer_info *connect_buffer(struct ustconsumer_instance *instance, pid_t pid,
 288                                    const char *trace, const char *channel,
 289                                    int channel_cpu)
 290 {
 291         struct buffer_info *buf;
 292         int result;
 293         struct shmid_ds shmds;
 294
 295         buf = (struct buffer_info *) zmalloc(sizeof(struct buffer_info));
 296         if(buf == NULL) {
 297                 ERR("add_buffer: insufficient memory");
 298                 return NULL;
 299         }
 300
 301         buf->trace = strdup(trace);
 302         if (!buf->trace) {
 303                 goto free_buf;
 304         }
 305
 306         buf->channel = strdup(channel);
 307         if (!buf->channel) {
 308                 goto free_buf_trace;
 309         }
 310
 311         result = asprintf(&buf->name, "%s_%d", channel, channel_cpu);
 312         if (result < 0 || buf->name == NULL) {
 313                 goto free_buf_channel;
 314         }
 315
 316         buf->channel_cpu = channel_cpu;
 317         buf->pid = pid;
 318
 319         result = ustcomm_connect_app(buf->pid, &buf->app_sock);
 320         if(result) {
 321                 WARN("unable to connect to process, it probably died before we were able to connect");
 322                 goto free_buf_name;
 323         }
 324
 325         /* get pidunique */
 326         result = get_pidunique(buf->app_sock, &buf->pidunique);
 327         if (result < 0) {
 328                 ERR("Failed to get pidunique");
 329                 goto close_app_sock;
 330         }
 331
 332         /* get shmid and pipe fd */
 333         result = get_buf_shmid_pipe_fd(buf->app_sock, buf, &buf->shmid,
 334                                        &buf->bufstruct_shmid, &buf->pipe_fd);
 335         if (result < 0) {
 336                 ERR("Failed to get buf_shmid and pipe_fd");
 337                 goto close_app_sock;
 338         } else {
 339                 struct stat temp;
 340                 fstat(buf->pipe_fd, &temp);
 341                 if (!S_ISFIFO(temp.st_mode)) {
 342                         ERR("Didn't receive a fifo from the app");
 343                         goto close_app_sock;
 344                 }
 345         }
 346
 347
 348         /* get number of subbufs and subbuf size */
 349         result = get_subbuf_num_size(buf->app_sock, buf, &buf->n_subbufs,
 350                                      &buf->subbuf_size);
 351         if (result < 0) {
 352                 ERR("Failed to get subbuf number and size");
 353                 goto close_fifo;
 354         }
 355
 356         /* attach memory */
 357         buf->mem = shmat(buf->shmid, NULL, 0);
 358         if(buf->mem == (void *) 0) {
 359                 PERROR("shmat");
 360                 goto close_fifo;
 361         }
 362         DBG("successfully attached buffer memory");
 363
 364         buf->bufstruct_mem = shmat(buf->bufstruct_shmid, NULL, 0);
 365         if(buf->bufstruct_mem == (void *) 0) {
 366                 PERROR("shmat");
 367                 goto shmdt_mem;
 368         }
 369         DBG("successfully attached buffer bufstruct memory");
 370
 371         /* obtain info on the memory segment */
 372         result = shmctl(buf->shmid, IPC_STAT, &shmds);
 373         if(result == -1) {
 374                 PERROR("shmctl");
 375                 goto shmdt_bufstruct_mem;
 376         }
 377         buf->memlen = shmds.shm_segsz;
 378
 379         /* Notify the application that we have mapped the buffer */
 380         result = notify_buffer_mapped(buf->app_sock, buf);
 381         if (result < 0) {
 382                 goto shmdt_bufstruct_mem;
 383         }
 384
 385         if(instance->callbacks->on_open_buffer)
 386                 instance->callbacks->on_open_buffer(instance->callbacks, buf);
 387
 388         pthread_mutex_lock(&instance->mutex);
 389         instance->active_buffers++;
 390         pthread_mutex_unlock(&instance->mutex);
 391
 392         return buf;
 393
 394 shmdt_bufstruct_mem:
 395         shmdt(buf->bufstruct_mem);
 396
 397 shmdt_mem:
 398         shmdt(buf->mem);
 399
 400 close_fifo:
 401         close(buf->pipe_fd);
 402
 403 close_app_sock:
 404         close(buf->app_sock);
 405
 406 free_buf_name:
 407         free(buf->name);
 408
 409 free_buf_channel:
 410         free(buf->channel);
 411
 412 free_buf_trace:
 413         free(buf->trace);
 414
 415 free_buf:
 416         free(buf);
 417         return NULL;
 418 }
 419
 420 static void destroy_buffer(struct ustconsumer_callbacks *callbacks,
 421                         struct buffer_info *buf)
 422 {
 423         int result;
 424
 425         result = close(buf->app_sock);
 426         if(result == -1) {
 427                 WARN("problem calling ustcomm_close_app");
 428         }
 429
 430         result = shmdt(buf->mem);
 431         if(result == -1) {
 432                 PERROR("shmdt");
 433         }
 434
 435         result = shmdt(buf->bufstruct_mem);
 436         if(result == -1) {
 437                 PERROR("shmdt");
 438         }
 439
 440         if(callbacks->on_close_buffer)
 441                 callbacks->on_close_buffer(callbacks, buf);
 442
 443         free(buf);
 444 }
 445
 446 int consumer_loop(struct ustconsumer_instance *instance, struct buffer_info *buf)
 447 {
 448         int result, read_result;
 449         char read_buf;
 450
 451         pthread_cleanup_push(decrement_active_buffers, instance);
 452
 453         for(;;) {
 454                 read_result = read(buf->pipe_fd, &read_buf, 1);
 455                 /* get the subbuffer */
 456                 if (read_result == 1) {
 457                         result = get_subbuffer(buf);
 458                         if (result < 0) {
 459                                 ERR("error getting subbuffer");
 460                                 continue;
 461                         } else if (result == GET_SUBBUF_DIED) {
 462                                 finish_consuming_dead_subbuffer(instance->callbacks, buf);
 463                                 break;
 464                         }
 465                 } else if ((read_result == -1 && (errno == ECONNRESET || errno == EPIPE)) ||
 466                            result == 0) {
 467                         DBG("App died while being traced");
 468                         finish_consuming_dead_subbuffer(instance->callbacks, buf);
 469                         break;
 470                 }
 471
 472                 if(instance->callbacks->on_read_subbuffer)
 473                         instance->callbacks->on_read_subbuffer(instance->callbacks, buf);
 474
 475                 /* put the subbuffer */
 476                 result = put_subbuffer(buf);
 477                 if(result == -1) {
 478                         ERR("unknown error putting subbuffer (channel=%s)", buf->name);
 479                         break;
 480                 }
 481                 else if(result == PUT_SUBBUF_PUSHED) {
 482                         ERR("Buffer overflow (channel=%s), reader pushed. This channel will not be usable passed this point.", buf->name);
 483                         break;
 484                 }
 485                 else if(result == PUT_SUBBUF_DIED) {
 486                         DBG("application died while putting subbuffer");
 487                         /* Skip the first subbuffer. We are not sure it is trustable
 488                          * because the put_subbuffer() did not complete.
 489                          */
 490                         /* TODO: check on_put_error return value */
 491                         if(instance->callbacks->on_put_error)
 492                                 instance->callbacks->on_put_error(instance->callbacks, buf);
 493
 494                         finish_consuming_dead_subbuffer(instance->callbacks, buf);
 495                         break;
 496                 }
 497                 else if(result == PUT_SUBBUF_DONE) {
 498                         /* Done with this subbuffer */
 499                         /* FIXME: add a case where this branch is used? Upon
 500                          * normal trace termination, at put_subbuf time, a
 501                          * special last-subbuffer code could be returned by
 502                          * the listener.
 503                          */
 504                         break;
 505                 }
 506                 else if(result == PUT_SUBBUF_OK) {
 507                 }
 508         }
 509
 510         DBG("thread for buffer %s is stopping", buf->name);
 511
 512         /* FIXME: destroy, unalloc... */
 513
 514         pthread_cleanup_pop(1);
 515
 516         return 0;
 517 }
 518
 519 struct consumer_thread_args {
 520         pid_t pid;
 521         const char *trace;
 522         const char *channel;
 523         int channel_cpu;
 524         struct ustconsumer_instance *instance;
 525 };
 526
 527 void *consumer_thread(void *arg)
 528 {
 529         struct buffer_info *buf;
 530         struct consumer_thread_args *args = (struct consumer_thread_args *) arg;
 531         int result;
 532         sigset_t sigset;
 533
 534         if(args->instance->callbacks->on_new_thread)
 535                 args->instance->callbacks->on_new_thread(args->instance->callbacks);
 536
 537         /* Block signals that should be handled by the main thread. */
 538         result = sigemptyset(&sigset);
 539         if(result == -1) {
 540                 PERROR("sigemptyset");
 541                 goto end;
 542         }
 543         result = sigaddset(&sigset, SIGTERM);
 544         if(result == -1) {
 545                 PERROR("sigaddset");
 546                 goto end;
 547         }
 548         result = sigaddset(&sigset, SIGINT);
 549         if(result == -1) {
 550                 PERROR("sigaddset");
 551                 goto end;
 552         }
 553         result = sigprocmask(SIG_BLOCK, &sigset, NULL);
 554         if(result == -1) {
 555                 PERROR("sigprocmask");
 556                 goto end;
 557         }
 558
 559         buf = connect_buffer(args->instance, args->pid, args->trace,
 560                              args->channel, args->channel_cpu);
 561         if(buf == NULL) {
 562                 ERR("failed to connect to buffer");
 563                 goto end;
 564         }
 565
 566         consumer_loop(args->instance, buf);
 567
 568         destroy_buffer(args->instance->callbacks, buf);
 569
 570         end:
 571
 572         if(args->instance->callbacks->on_close_thread)
 573                 args->instance->callbacks->on_close_thread(args->instance->callbacks);
 574
 575         free((void *)args->channel);
 576         free(args);
 577         return NULL;
 578 }
 579
 580 int start_consuming_buffer(struct ustconsumer_instance *instance, pid_t pid,
 581                            const char *trace, const char *channel,
 582                            int channel_cpu)
 583 {
 584         pthread_t thr;
 585         struct consumer_thread_args *args;
 586         int result;
 587
 588         DBG("beginning of start_consuming_buffer: args: pid %d bufname %s_%d", pid, channel,
 589             channel_cpu);
 590
 591         args = (struct consumer_thread_args *) zmalloc(sizeof(struct consumer_thread_args));
 592         if (!args) {
 593                 return -ENOMEM;
 594         }
 595
 596         args->pid = pid;
 597         args->trace = strdup(trace);
 598         args->channel = strdup(channel);
 599         args->channel_cpu = channel_cpu;
 600         args->instance = instance;
 601         DBG("beginning2 of start_consuming_buffer: args: pid %d trace %s"
 602             " bufname %s_%d", args->pid, args->trace, args->channel, args->channel_cpu);
 603
 604         result = pthread_create(&thr, NULL, consumer_thread, args);
 605         if(result == -1) {
 606                 ERR("pthread_create failed");
 607                 return -1;
 608         }
 609         result = pthread_detach(thr);
 610         if(result == -1) {
 611                 ERR("pthread_detach failed");
 612                 return -1;
 613         }
 614         DBG("end of start_consuming_buffer: args: pid %d trace %s "
 615             "bufname %s_%d", args->pid, args->channel, args->trace, args->channel_cpu);
 616
 617         return 0;
 618 }
 619 static void process_client_cmd(int sock, struct ustcomm_header *req_header,
 620                                char *recvbuf, struct ustconsumer_instance *instance)
 621 {
 622         int result;
 623         struct ustcomm_header _res_header;
 624         struct ustcomm_header *res_header = &_res_header;
 625         struct ustcomm_buffer_info *buf_inf;
 626
 627         DBG("Processing client command");
 628
 629         switch (req_header->command) {
 630         case CONSUME_BUFFER:
 631
 632                 buf_inf = (struct ustcomm_buffer_info *)recvbuf;
 633                 result = ustcomm_unpack_buffer_info(buf_inf);
 634                 if (result < 0) {
 635                         ERR("Couldn't unpack buffer info");
 636                         return;
 637                 }
 638
 639                 DBG("Going to consume trace %s buffer %s_%d in process %d",
 640                     buf_inf->trace, buf_inf->channel, buf_inf->ch_cpu,
 641                     buf_inf->pid);
 642                 result = start_consuming_buffer(instance, buf_inf->pid,
 643                                                 buf_inf->trace,
 644                                                 buf_inf->channel,
 645                                                 buf_inf->ch_cpu);
 646                 if (result < 0) {
 647                         ERR("error in add_buffer");
 648                         return;
 649                 }
 650
 651                 res_header->result = 0;
 652                 break;
 653         case EXIT:
 654                 res_header->result = 0;
 655                 /* Only there to force poll to return */
 656                 break;
 657         default:
 658                 res_header->result = -EINVAL;
 659                 WARN("unknown command: %d", req_header->command);
 660         }
 661
 662         if (ustcomm_send(sock, res_header, NULL) <= 0) {
 663                 ERR("couldn't send command response");
 664         }
 665 }
 666
 667 #define MAX_EVENTS 10
 668
 669 int ustconsumer_start_instance(struct ustconsumer_instance *instance)
 670 {
 671         struct ustcomm_header recv_hdr;
 672         char recv_buf[USTCOMM_BUFFER_SIZE];
 673         struct ustcomm_sock *epoll_sock;
 674         struct epoll_event events[MAX_EVENTS];
 675         struct sockaddr addr;
 676         int result, epoll_fd, accept_fd, nfds, i, addr_size, timeout;
 677
 678         if(!instance->is_init) {
 679                 ERR("libustconsumer instance not initialized");
 680                 return 1;
 681         }
 682         epoll_fd = instance->epoll_fd;
 683
 684         timeout = -1;
 685
 686         /* app loop */
 687         for(;;) {
 688                 nfds = epoll_wait(epoll_fd, events, MAX_EVENTS, timeout);
 689                 if (nfds == -1 && errno == EINTR) {
 690                         /* Caught signal */
 691                 } else if (nfds == -1) {
 692                         PERROR("ustconsumer_start_instance: epoll_wait failed");
 693                         continue;
 694                 }
 695
 696                 for (i = 0; i < nfds; ++i) {
 697                         epoll_sock = (struct ustcomm_sock *)events[i].data.ptr;
 698                         if (epoll_sock == instance->listen_sock) {
 699                                 addr_size = sizeof(struct sockaddr);
 700                                 accept_fd = accept(epoll_sock->fd,
 701                                                    &addr,
 702                                                    (socklen_t *)&addr_size);
 703                                 if (accept_fd == -1) {
 704                                         PERROR("ustconsumer_start_instance: "
 705                                                "accept failed");
 706                                         continue;
 707                                 }
 708                                 ustcomm_init_sock(accept_fd, epoll_fd,
 709                                                  &instance->connections);
 710                         } else {
 711                                 result = ustcomm_recv(epoll_sock->fd, &recv_hdr,
 712                                                       recv_buf);
 713                                 if (result < 1) {
 714                                         ustcomm_del_sock(epoll_sock, 0);
 715                                 } else {
 716                                         process_client_cmd(epoll_sock->fd,
 717                                                            &recv_hdr, recv_buf,
 718                                                            instance);
 719                                 }
 720
 721                         }
 722                 }
 723
 724                 if (instance->quit_program) {
 725                         pthread_mutex_lock(&instance->mutex);
 726                         if(instance->active_buffers == 0) {
 727                                 pthread_mutex_unlock(&instance->mutex);
 728                                 break;
 729                         }
 730                         pthread_mutex_unlock(&instance->mutex);
 731                         timeout = 100;
 732                 }
 733         }
 734
 735         if(instance->callbacks->on_trace_end)
 736                 instance->callbacks->on_trace_end(instance);
 737
 738         ustconsumer_delete_instance(instance);
 739
 740         return 0;
 741 }
 742
 743 /* FIXME: threads and connections !? */
 744 void ustconsumer_delete_instance(struct ustconsumer_instance *instance)
 745 {
 746         if (instance->is_init) {
 747                 ustcomm_del_named_sock(instance->listen_sock, 0);
 748                 close(instance->epoll_fd);
 749         }
 750
 751         pthread_mutex_destroy(&instance->mutex);
 752         free(instance->sock_path);
 753         free(instance);
 754 }
 755
 756 /* FIXME: Do something about the fixed path length, maybe get rid
 757  * of the whole concept and use a pipe?
 758  */
 759 int ustconsumer_stop_instance(struct ustconsumer_instance *instance, int send_msg)
 760 {
 761         int result;
 762         int fd;
 763         int bytes = 0;
 764
 765         char msg[] = "exit";
 766
 767         instance->quit_program = 1;
 768
 769         if(!send_msg)
 770                 return 0;
 771
 772         /* Send a message through the socket to force poll to return */
 773
 774         struct sockaddr_un addr;
 775
 776         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 777         if(result == -1) {
 778                 PERROR("socket");
 779                 return 1;
 780         }
 781
 782         addr.sun_family = AF_UNIX;
 783
 784         strncpy(addr.sun_path, instance->sock_path, UNIX_PATH_MAX);
 785         addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 786
 787         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 788         if(result == -1) {
 789                 PERROR("connect");
 790         }
 791
 792         while(bytes != sizeof(msg))
 793                 bytes += send(fd, msg, sizeof(msg), 0);
 794
 795         close(fd);
 796
 797         return 0;
 798 }
 799
 800 struct ustconsumer_instance
 801 *ustconsumer_new_instance(struct ustconsumer_callbacks *callbacks,
 802                       char *sock_path)
 803 {
 804         struct ustconsumer_instance *instance =
 805                 zmalloc(sizeof(struct ustconsumer_instance));
 806         if(!instance) {
 807                 return NULL;
 808         }
 809
 810         instance->callbacks = callbacks;
 811         instance->quit_program = 0;
 812         instance->is_init = 0;
 813         instance->active_buffers = 0;
 814         pthread_mutex_init(&instance->mutex, NULL);
 815
 816         if (sock_path) {
 817                 instance->sock_path = strdup(sock_path);
 818         } else {
 819                 instance->sock_path = NULL;
 820         }
 821
 822         return instance;
 823 }
 824
 825 static int init_ustconsumer_socket(struct ustconsumer_instance *instance)
 826 {
 827         char *name;
 828
 829         if (instance->sock_path) {
 830                 if (asprintf(&name, "%s", instance->sock_path) < 0) {
 831                         ERR("ustcomm_init_ustconsumer : asprintf failed (sock_path %s)",
 832                             instance->sock_path);
 833                         return -1;
 834                 }
 835         } else {
 836                 int result;
 837
 838                 /* Only check if socket dir exists if we are using the default directory */
 839                 result = ensure_dir_exists(SOCK_DIR);
 840                 if (result == -1) {
 841                         ERR("Unable to create socket directory %s", SOCK_DIR);
 842                         return -1;
 843                 }
 844
 845                 if (asprintf(&name, "%s/%s", SOCK_DIR, "ustconsumer") < 0) {
 846                         ERR("ustcomm_init_ustconsumer : asprintf failed (%s/ustconsumer)",
 847                             SOCK_DIR);
 848                         return -1;
 849                 }
 850         }
 851
 852         /* Set up epoll */
 853         instance->epoll_fd = epoll_create(MAX_EVENTS);
 854         if (instance->epoll_fd == -1) {
 855                 ERR("epoll_create failed, start instance bailing");
 856                 goto free_name;
 857         }
 858
 859         /* Create the named socket */
 860         instance->listen_sock = ustcomm_init_named_socket(name,
 861                                                           instance->epoll_fd);
 862         if(!instance->listen_sock) {
 863                 ERR("error initializing named socket at %s", name);
 864                 goto close_epoll;
 865         }
 866
 867         CDS_INIT_LIST_HEAD(&instance->connections);
 868
 869         free(name);
 870
 871         return 0;
 872
 873 close_epoll:
 874         close(instance->epoll_fd);
 875 free_name:
 876         free(name);
 877
 878         return -1;
 879 }
 880
 881 int ustconsumer_init_instance(struct ustconsumer_instance *instance)
 882 {
 883         int result;
 884         result = init_ustconsumer_socket(instance);
 885         if(result == -1) {
 886                 ERR("failed to initialize socket");
 887                 return 1;
 888         }
 889         instance->is_init = 1;
 890         return 0;
 891 }
 892