libustd/libustd.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/shm.h>
  22 #include <unistd.h>
  23 #include <pthread.h>
  24 #include <signal.h>
  25
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <errno.h>
  30 #include <assert.h>
  31
  32 #include "libustd.h"
  33 #include "usterr.h"
  34 #include "ustcomm.h"
  35
  36 /* return value: 0 = subbuffer is finished, it won't produce data anymore
  37  *               1 = got subbuffer successfully
  38  *               <0 = error
  39  */
  40
  41 #define GET_SUBBUF_OK 1
  42 #define GET_SUBBUF_DONE 0
  43 #define GET_SUBBUF_DIED 2
  44
  45 #define PUT_SUBBUF_OK 1
  46 #define PUT_SUBBUF_DIED 0
  47 #define PUT_SUBBUF_PUSHED 2
  48 #define PUT_SUBBUF_DONE 3
  49
  50 #define UNIX_PATH_MAX 108
  51
  52 int get_subbuffer(struct buffer_info *buf)
  53 {
  54         char *send_msg=NULL;
  55         char *received_msg=NULL;
  56         char *rep_code=NULL;
  57         int retval;
  58         int result;
  59
  60         asprintf(&send_msg, "get_subbuffer %s", buf->name);
  61         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
  62         if((result == -1 && (errno == ECONNRESET || errno == EPIPE)) || result == 0) {
  63                 DBG("app died while being traced");
  64                 retval = GET_SUBBUF_DIED;
  65                 goto end;
  66         }
  67         else if(result < 0) {
  68                 ERR("get_subbuffer: ustcomm_send_request failed");
  69                 retval = -1;
  70                 goto end;
  71         }
  72
  73         result = sscanf(received_msg, "%as %ld", &rep_code, &buf->consumed_old);
  74         if(result != 2 && result != 1) {
  75                 ERR("unable to parse response to get_subbuffer");
  76                 retval = -1;
  77                 free(received_msg);
  78                 goto end_rep;
  79         }
  80
  81         if(!strcmp(rep_code, "OK")) {
  82                 DBG("got subbuffer %s", buf->name);
  83                 retval = GET_SUBBUF_OK;
  84         }
  85         else if(nth_token_is(received_msg, "END", 0) == 1) {
  86                 retval = GET_SUBBUF_DONE;
  87                 goto end_rep;
  88         }
  89         else if(!strcmp(received_msg, "NOTFOUND")) {
  90                 DBG("For buffer %s, the trace was not found. This likely means it was destroyed by the user.", buf->name);
  91                 retval = GET_SUBBUF_DIED;
  92                 goto end_rep;
  93         }
  94         else {
  95                 DBG("error getting subbuffer %s", buf->name);
  96                 retval = -1;
  97         }
  98
  99         /* FIXME: free correctly the stuff */
 100 end_rep:
 101         if(rep_code)
 102                 free(rep_code);
 103 end:
 104         if(send_msg)
 105                 free(send_msg);
 106         if(received_msg)
 107                 free(received_msg);
 108
 109         return retval;
 110 }
 111
 112 int put_subbuffer(struct buffer_info *buf)
 113 {
 114         char *send_msg=NULL;
 115         char *received_msg=NULL;
 116         char *rep_code=NULL;
 117         int retval;
 118         int result;
 119
 120         asprintf(&send_msg, "put_subbuffer %s %ld", buf->name, buf->consumed_old);
 121         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 122         if(result < 0 && (errno == ECONNRESET || errno == EPIPE)) {
 123                 retval = PUT_SUBBUF_DIED;
 124                 goto end;
 125         }
 126         else if(result < 0) {
 127                 ERR("put_subbuffer: send_message failed");
 128                 retval = -1;
 129                 goto end;
 130         }
 131         else if(result == 0) {
 132                 /* Program seems finished. However this might not be
 133                  * the last subbuffer that has to be collected.
 134                  */
 135                 retval = PUT_SUBBUF_DIED;
 136                 goto end;
 137         }
 138
 139         result = sscanf(received_msg, "%as", &rep_code);
 140         if(result != 1) {
 141                 ERR("unable to parse response to put_subbuffer");
 142                 retval = -1;
 143                 goto end_rep;
 144         }
 145
 146         if(!strcmp(rep_code, "OK")) {
 147                 DBG("subbuffer put %s", buf->name);
 148                 retval = PUT_SUBBUF_OK;
 149         }
 150         else if(!strcmp(received_msg, "NOTFOUND")) {
 151                 DBG("For buffer %s, the trace was not found. This likely means it was destroyed by the user.", buf->name);
 152                 /* However, maybe this was not the last subbuffer. So
 153                  * we return the program died.
 154                  */
 155                 retval = PUT_SUBBUF_DIED;
 156                 goto end_rep;
 157         }
 158         else {
 159                 DBG("put_subbuffer: received error, we were pushed");
 160                 retval = PUT_SUBBUF_PUSHED;
 161                 goto end_rep;
 162         }
 163
 164 end_rep:
 165         if(rep_code)
 166                 free(rep_code);
 167
 168 end:
 169         if(send_msg)
 170                 free(send_msg);
 171         if(received_msg)
 172                 free(received_msg);
 173
 174         return retval;
 175 }
 176
 177 void decrement_active_buffers(void *arg)
 178 {
 179         struct libustd_instance *instance = arg;
 180         pthread_mutex_lock(&instance->mutex);
 181         instance->active_buffers--;
 182         pthread_mutex_unlock(&instance->mutex);
 183 }
 184
 185 struct buffer_info *connect_buffer(struct libustd_instance *instance, pid_t pid, const char *bufname)
 186 {
 187         struct buffer_info *buf;
 188         char *send_msg;
 189         char *received_msg;
 190         int result;
 191         char *tmp;
 192         int fd;
 193         struct shmid_ds shmds;
 194
 195         buf = (struct buffer_info *) malloc(sizeof(struct buffer_info));
 196         if(buf == NULL) {
 197                 ERR("add_buffer: insufficient memory");
 198                 return NULL;
 199         }
 200
 201         buf->name = bufname;
 202         buf->pid = pid;
 203
 204         /* connect to app */
 205         result = ustcomm_connect_app(buf->pid, &buf->conn);
 206         if(result) {
 207                 WARN("unable to connect to process, it probably died before we were able to connect");
 208                 return NULL;
 209         }
 210
 211         /* get pidunique */
 212         asprintf(&send_msg, "get_pidunique");
 213         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 214         free(send_msg);
 215         if(result == -1) {
 216                 ERR("problem in ustcomm_send_request(get_pidunique)");
 217                 return NULL;
 218         }
 219         if(result == 0) {
 220                 goto error;
 221         }
 222
 223         result = sscanf(received_msg, "%lld", &buf->pidunique);
 224         if(result != 1) {
 225                 ERR("unable to parse response to get_pidunique");
 226                 return NULL;
 227         }
 228         free(received_msg);
 229         DBG("got pidunique %lld", buf->pidunique);
 230
 231         /* get shmid */
 232         asprintf(&send_msg, "get_shmid %s", buf->name);
 233         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 234         free(send_msg);
 235         if(result == -1) {
 236                 ERR("problem in ustcomm_send_request(get_shmid)");
 237                 return NULL;
 238         }
 239         if(result == 0) {
 240                 goto error;
 241         }
 242
 243         result = sscanf(received_msg, "%d %d", &buf->shmid, &buf->bufstruct_shmid);
 244         if(result != 2) {
 245                 ERR("unable to parse response to get_shmid (\"%s\")", received_msg);
 246                 return NULL;
 247         }
 248         free(received_msg);
 249         DBG("got shmids %d %d", buf->shmid, buf->bufstruct_shmid);
 250
 251         /* get n_subbufs */
 252         asprintf(&send_msg, "get_n_subbufs %s", buf->name);
 253         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 254         free(send_msg);
 255         if(result == -1) {
 256                 ERR("problem in ustcomm_send_request(g_n_subbufs)");
 257                 return NULL;
 258         }
 259         if(result == 0) {
 260                 goto error;
 261         }
 262
 263         result = sscanf(received_msg, "%d", &buf->n_subbufs);
 264         if(result != 1) {
 265                 ERR("unable to parse response to get_n_subbufs");
 266                 return NULL;
 267         }
 268         free(received_msg);
 269         DBG("got n_subbufs %d", buf->n_subbufs);
 270
 271         /* get subbuf size */
 272         asprintf(&send_msg, "get_subbuf_size %s", buf->name);
 273         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 274         free(send_msg);
 275         if(result == -1) {
 276                 ERR("problem in ustcomm_send_request(get_subbuf_size)");
 277                 return NULL;
 278         }
 279         if(result == 0) {
 280                 goto error;
 281         }
 282
 283         result = sscanf(received_msg, "%d", &buf->subbuf_size);
 284         if(result != 1) {
 285                 ERR("unable to parse response to get_subbuf_size");
 286                 return NULL;
 287         }
 288         free(received_msg);
 289         DBG("got subbuf_size %d", buf->subbuf_size);
 290
 291         /* attach memory */
 292         buf->mem = shmat(buf->shmid, NULL, 0);
 293         if(buf->mem == (void *) 0) {
 294                 PERROR("shmat");
 295                 return NULL;
 296         }
 297         DBG("successfully attached buffer memory");
 298
 299         buf->bufstruct_mem = shmat(buf->bufstruct_shmid, NULL, 0);
 300         if(buf->bufstruct_mem == (void *) 0) {
 301                 PERROR("shmat");
 302                 return NULL;
 303         }
 304         DBG("successfully attached buffer bufstruct memory");
 305
 306         /* obtain info on the memory segment */
 307         result = shmctl(buf->shmid, IPC_STAT, &shmds);
 308         if(result == -1) {
 309                 PERROR("shmctl");
 310                 return NULL;
 311         }
 312         buf->memlen = shmds.shm_segsz;
 313
 314         if(instance->callbacks->on_open_buffer)
 315                 instance->callbacks->on_open_buffer(instance->callbacks, buf);
 316
 317         pthread_mutex_lock(&instance->mutex);
 318         instance->active_buffers++;
 319         pthread_mutex_unlock(&instance->mutex);
 320
 321         return buf;
 322
 323 error:
 324         free(buf);
 325         return NULL;
 326 }
 327
 328 static void destroy_buffer(struct libustd_callbacks *callbacks,
 329                         struct buffer_info *buf)
 330 {
 331         int result;
 332
 333         result = ustcomm_close_app(&buf->conn);
 334         if(result == -1) {
 335                 WARN("problem calling ustcomm_close_app");
 336         }
 337
 338         result = shmdt(buf->mem);
 339         if(result == -1) {
 340                 PERROR("shmdt");
 341         }
 342
 343         result = shmdt(buf->bufstruct_mem);
 344         if(result == -1) {
 345                 PERROR("shmdt");
 346         }
 347
 348         if(callbacks->on_close_buffer)
 349                 callbacks->on_close_buffer(callbacks, buf);
 350
 351         free(buf);
 352 }
 353
 354 int consumer_loop(struct libustd_instance *instance, struct buffer_info *buf)
 355 {
 356         int result;
 357
 358         pthread_cleanup_push(decrement_active_buffers, instance);
 359
 360         for(;;) {
 361                 /* get the subbuffer */
 362                 result = get_subbuffer(buf);
 363                 if(result == -1) {
 364                         ERR("error getting subbuffer");
 365                         continue;
 366                 }
 367                 else if(result == GET_SUBBUF_DONE) {
 368                         /* this is done */
 369                         break;
 370                 }
 371                 else if(result == GET_SUBBUF_DIED) {
 372                         finish_consuming_dead_subbuffer(instance->callbacks, buf);
 373                         break;
 374                 }
 375
 376                 if(instance->callbacks->on_read_subbuffer)
 377                         instance->callbacks->on_read_subbuffer(instance->callbacks, buf);
 378
 379                 /* put the subbuffer */
 380                 result = put_subbuffer(buf);
 381                 if(result == -1) {
 382                         ERR("unknown error putting subbuffer (channel=%s)", buf->name);
 383                         break;
 384                 }
 385                 else if(result == PUT_SUBBUF_PUSHED) {
 386                         ERR("Buffer overflow (channel=%s), reader pushed. This channel will not be usable passed this point.", buf->name);
 387                         break;
 388                 }
 389                 else if(result == PUT_SUBBUF_DIED) {
 390                         DBG("application died while putting subbuffer");
 391                         /* Skip the first subbuffer. We are not sure it is trustable
 392                          * because the put_subbuffer() did not complete.
 393                          */
 394                         if(instance->callbacks->on_put_error)
 395                                 instance->callbacks->on_put_error(instance->callbacks, buf);
 396
 397                         finish_consuming_dead_subbuffer(instance->callbacks, buf);
 398                         break;
 399                 }
 400                 else if(result == PUT_SUBBUF_DONE) {
 401                         /* Done with this subbuffer */
 402                         /* FIXME: add a case where this branch is used? Upon
 403                          * normal trace termination, at put_subbuf time, a
 404                          * special last-subbuffer code could be returned by
 405                          * the listener.
 406                          */
 407                         break;
 408                 }
 409                 else if(result == PUT_SUBBUF_OK) {
 410                 }
 411         }
 412
 413         DBG("thread for buffer %s is stopping", buf->name);
 414
 415         /* FIXME: destroy, unalloc... */
 416
 417         pthread_cleanup_pop(1);
 418
 419         return 0;
 420 }
 421
 422 struct consumer_thread_args {
 423         pid_t pid;
 424         const char *bufname;
 425         struct libustd_instance *instance;
 426 };
 427
 428 void *consumer_thread(void *arg)
 429 {
 430         struct buffer_info *buf;
 431         struct consumer_thread_args *args = (struct consumer_thread_args *) arg;
 432         int result;
 433         sigset_t sigset;
 434
 435         DBG("GOT ARGS: pid %d bufname %s", args->pid, args->bufname);
 436
 437         if(args->instance->callbacks->on_new_thread)
 438                 args->instance->callbacks->on_new_thread(args->instance->callbacks);
 439
 440         /* Block signals that should be handled by the main thread. */
 441         result = sigemptyset(&sigset);
 442         if(result == -1) {
 443                 PERROR("sigemptyset");
 444                 goto end;
 445         }
 446         result = sigaddset(&sigset, SIGTERM);
 447         if(result == -1) {
 448                 PERROR("sigaddset");
 449                 goto end;
 450         }
 451         result = sigaddset(&sigset, SIGINT);
 452         if(result == -1) {
 453                 PERROR("sigaddset");
 454                 goto end;
 455         }
 456         result = sigprocmask(SIG_BLOCK, &sigset, NULL);
 457         if(result == -1) {
 458                 PERROR("sigprocmask");
 459                 goto end;
 460         }
 461
 462         buf = connect_buffer(args->instance, args->pid, args->bufname);
 463         if(buf == NULL) {
 464                 ERR("failed to connect to buffer");
 465                 goto end;
 466         }
 467
 468         consumer_loop(args->instance, buf);
 469
 470         destroy_buffer(args->instance->callbacks, buf);
 471
 472         end:
 473
 474         if(args->instance->callbacks->on_close_thread)
 475                 args->instance->callbacks->on_close_thread(args->instance->callbacks);
 476
 477         free((void *)args->bufname);
 478         free(args);
 479         return NULL;
 480 }
 481
 482 int start_consuming_buffer(
 483         struct libustd_instance *instance, pid_t pid, const char *bufname)
 484 {
 485         pthread_t thr;
 486         struct consumer_thread_args *args;
 487         int result;
 488
 489         DBG("beginning of start_consuming_buffer: args: pid %d bufname %s", pid, bufname);
 490
 491         args = (struct consumer_thread_args *) malloc(sizeof(struct consumer_thread_args));
 492
 493         args->pid = pid;
 494         args->bufname = strdup(bufname);
 495         args->instance = instance;
 496         DBG("beginning2 of start_consuming_buffer: args: pid %d bufname %s", args->pid, args->bufname);
 497
 498         result = pthread_create(&thr, NULL, consumer_thread, args);
 499         if(result == -1) {
 500                 ERR("pthread_create failed");
 501                 return -1;
 502         }
 503         result = pthread_detach(thr);
 504         if(result == -1) {
 505                 ERR("pthread_detach failed");
 506                 return -1;
 507         }
 508         DBG("end of start_consuming_buffer: args: pid %d bufname %s", args->pid, args->bufname);
 509
 510         return 0;
 511 }
 512
 513 int libustd_start_instance(struct libustd_instance *instance)
 514 {
 515         int result;
 516         int timeout = -1;
 517
 518         if(!instance->is_init) {
 519                 ERR("libustd instance not initialized");
 520                 return 1;
 521         }
 522
 523         /* app loop */
 524         for(;;) {
 525                 char *recvbuf;
 526
 527                 /* check for requests on our public socket */
 528                 result = ustcomm_ustd_recv_message(&instance->comm, &recvbuf, NULL, timeout);
 529                 if(result == -1 && errno == EINTR) {
 530                         /* Caught signal */
 531                 }
 532                 else if(result == -1) {
 533                         ERR("error in ustcomm_ustd_recv_message");
 534                         goto loop_end;
 535                 }
 536                 else if(result > 0) {
 537                         if(!strncmp(recvbuf, "collect", 7)) {
 538                                 pid_t pid;
 539                                 char *bufname;
 540                                 int result;
 541
 542                                 result = sscanf(recvbuf, "%*s %d %50as", &pid, &bufname);
 543                                 if(result != 2) {
 544                                         ERR("parsing error: %s", recvbuf);
 545                                         goto free_bufname;
 546                                 }
 547
 548                                 result = start_consuming_buffer(instance, pid, bufname);
 549                                 if(result < 0) {
 550                                         ERR("error in add_buffer");
 551                                         goto free_bufname;
 552                                 }
 553
 554                                 free_bufname:
 555                                 free(bufname);
 556                         }
 557                         else if(!strncmp(recvbuf, "exit", 4)) {
 558                                 /* Only there to force poll to return */
 559                         }
 560                         else {
 561                                 WARN("unknown command: %s", recvbuf);
 562                         }
 563
 564                         free(recvbuf);
 565                 }
 566
 567                 loop_end:
 568
 569                 if(instance->quit_program) {
 570                         pthread_mutex_lock(&instance->mutex);
 571                         if(instance->active_buffers == 0) {
 572                                 pthread_mutex_unlock(&instance->mutex);
 573                                 break;
 574                         }
 575                         pthread_mutex_unlock(&instance->mutex);
 576                         timeout = 100;
 577                 }
 578         }
 579
 580         if(instance->callbacks->on_trace_end)
 581                 instance->callbacks->on_trace_end(instance);
 582
 583         libustd_delete_instance(instance);
 584
 585         return 0;
 586 }
 587
 588 void libustd_delete_instance(struct libustd_instance *instance)
 589 {
 590         if(instance->is_init)
 591                 ustcomm_fini_ustd(&instance->comm);
 592
 593         pthread_mutex_destroy(&instance->mutex);
 594         free(instance->sock_path);
 595         free(instance);
 596 }
 597
 598 int libustd_stop_instance(struct libustd_instance *instance, int send_msg)
 599 {
 600         int result;
 601         int fd;
 602         int bytes = 0;
 603
 604         char msg[] = "exit";
 605
 606         instance->quit_program = 1;
 607
 608         if(!send_msg)
 609                 return 0;
 610
 611         /* Send a message through the socket to force poll to return */
 612
 613         struct sockaddr_un addr;
 614
 615         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 616         if(result == -1) {
 617                 PERROR("socket");
 618                 return 1;
 619         }
 620
 621         addr.sun_family = AF_UNIX;
 622
 623         strncpy(addr.sun_path, instance->sock_path, UNIX_PATH_MAX);
 624         addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 625
 626         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 627         if(result == -1) {
 628                 PERROR("connect");
 629         }
 630
 631         while(bytes != sizeof(msg))
 632                 bytes += send(fd, msg, sizeof(msg), 0);
 633
 634         close(fd);
 635
 636         return 0;
 637 }
 638
 639 struct libustd_instance *libustd_new_instance(
 640         struct libustd_callbacks *callbacks, char *sock_path)
 641 {
 642         struct libustd_instance *instance =
 643                 malloc(sizeof(struct libustd_instance));
 644         if(!instance)
 645                 return NULL;
 646
 647         instance->callbacks = callbacks;
 648         instance->quit_program = 0;
 649         instance->is_init = 0;
 650         instance->active_buffers = 0;
 651         pthread_mutex_init(&instance->mutex, NULL);
 652
 653         if(sock_path)
 654                 instance->sock_path = strdup(sock_path);
 655         else
 656                 instance->sock_path = NULL;
 657
 658         return instance;
 659 }
 660
 661 int libustd_init_instance(struct libustd_instance *instance)
 662 {
 663         int result;
 664         result = ustcomm_init_ustd(&instance->comm, instance->sock_path);
 665         if(result == -1) {
 666                 ERR("failed to initialize socket");
 667                 return 1;
 668         }
 669         instance->is_init = 1;
 670         return 0;
 671 }
 672