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         struct shmid_ds shmds;
 192
 193         buf = (struct buffer_info *) malloc(sizeof(struct buffer_info));
 194         if(buf == NULL) {
 195                 ERR("add_buffer: insufficient memory");
 196                 return NULL;
 197         }
 198
 199         buf->name = bufname;
 200         buf->pid = pid;
 201
 202         /* connect to app */
 203         result = ustcomm_connect_app(buf->pid, &buf->conn);
 204         if(result) {
 205                 WARN("unable to connect to process, it probably died before we were able to connect");
 206                 return NULL;
 207         }
 208
 209         /* get pidunique */
 210         asprintf(&send_msg, "get_pidunique");
 211         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 212         free(send_msg);
 213         if(result == -1) {
 214                 ERR("problem in ustcomm_send_request(get_pidunique)");
 215                 return NULL;
 216         }
 217         if(result == 0) {
 218                 goto error;
 219         }
 220
 221         result = sscanf(received_msg, "%lld", &buf->pidunique);
 222         if(result != 1) {
 223                 ERR("unable to parse response to get_pidunique");
 224                 return NULL;
 225         }
 226         free(received_msg);
 227         DBG("got pidunique %lld", buf->pidunique);
 228
 229         /* get shmid */
 230         asprintf(&send_msg, "get_shmid %s", buf->name);
 231         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 232         free(send_msg);
 233         if(result == -1) {
 234                 ERR("problem in ustcomm_send_request(get_shmid)");
 235                 return NULL;
 236         }
 237         if(result == 0) {
 238                 goto error;
 239         }
 240
 241         result = sscanf(received_msg, "%d %d", &buf->shmid, &buf->bufstruct_shmid);
 242         if(result != 2) {
 243                 ERR("unable to parse response to get_shmid (\"%s\")", received_msg);
 244                 return NULL;
 245         }
 246         free(received_msg);
 247         DBG("got shmids %d %d", buf->shmid, buf->bufstruct_shmid);
 248
 249         /* get n_subbufs */
 250         asprintf(&send_msg, "get_n_subbufs %s", buf->name);
 251         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 252         free(send_msg);
 253         if(result == -1) {
 254                 ERR("problem in ustcomm_send_request(g_n_subbufs)");
 255                 return NULL;
 256         }
 257         if(result == 0) {
 258                 goto error;
 259         }
 260
 261         result = sscanf(received_msg, "%d", &buf->n_subbufs);
 262         if(result != 1) {
 263                 ERR("unable to parse response to get_n_subbufs");
 264                 return NULL;
 265         }
 266         free(received_msg);
 267         DBG("got n_subbufs %d", buf->n_subbufs);
 268
 269         /* get subbuf size */
 270         asprintf(&send_msg, "get_subbuf_size %s", buf->name);
 271         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 272         free(send_msg);
 273         if(result == -1) {
 274                 ERR("problem in ustcomm_send_request(get_subbuf_size)");
 275                 return NULL;
 276         }
 277         if(result == 0) {
 278                 goto error;
 279         }
 280
 281         result = sscanf(received_msg, "%d", &buf->subbuf_size);
 282         if(result != 1) {
 283                 ERR("unable to parse response to get_subbuf_size");
 284                 return NULL;
 285         }
 286         free(received_msg);
 287         DBG("got subbuf_size %d", buf->subbuf_size);
 288
 289         /* attach memory */
 290         buf->mem = shmat(buf->shmid, NULL, 0);
 291         if(buf->mem == (void *) 0) {
 292                 PERROR("shmat");
 293                 return NULL;
 294         }
 295         DBG("successfully attached buffer memory");
 296
 297         buf->bufstruct_mem = shmat(buf->bufstruct_shmid, NULL, 0);
 298         if(buf->bufstruct_mem == (void *) 0) {
 299                 PERROR("shmat");
 300                 return NULL;
 301         }
 302         DBG("successfully attached buffer bufstruct memory");
 303
 304         /* obtain info on the memory segment */
 305         result = shmctl(buf->shmid, IPC_STAT, &shmds);
 306         if(result == -1) {
 307                 PERROR("shmctl");
 308                 return NULL;
 309         }
 310         buf->memlen = shmds.shm_segsz;
 311
 312         if(instance->callbacks->on_open_buffer)
 313                 instance->callbacks->on_open_buffer(instance->callbacks, buf);
 314
 315         pthread_mutex_lock(&instance->mutex);
 316         instance->active_buffers++;
 317         pthread_mutex_unlock(&instance->mutex);
 318
 319         return buf;
 320
 321 error:
 322         free(buf);
 323         return NULL;
 324 }
 325
 326 static void destroy_buffer(struct libustd_callbacks *callbacks,
 327                         struct buffer_info *buf)
 328 {
 329         int result;
 330
 331         result = ustcomm_close_app(&buf->conn);
 332         if(result == -1) {
 333                 WARN("problem calling ustcomm_close_app");
 334         }
 335
 336         result = shmdt(buf->mem);
 337         if(result == -1) {
 338                 PERROR("shmdt");
 339         }
 340
 341         result = shmdt(buf->bufstruct_mem);
 342         if(result == -1) {
 343                 PERROR("shmdt");
 344         }
 345
 346         if(callbacks->on_close_buffer)
 347                 callbacks->on_close_buffer(callbacks, buf);
 348
 349         free(buf);
 350 }
 351
 352 int consumer_loop(struct libustd_instance *instance, struct buffer_info *buf)
 353 {
 354         int result;
 355
 356         pthread_cleanup_push(decrement_active_buffers, instance);
 357
 358         for(;;) {
 359                 /* get the subbuffer */
 360                 result = get_subbuffer(buf);
 361                 if(result == -1) {
 362                         ERR("error getting subbuffer");
 363                         continue;
 364                 }
 365                 else if(result == GET_SUBBUF_DONE) {
 366                         /* this is done */
 367                         break;
 368                 }
 369                 else if(result == GET_SUBBUF_DIED) {
 370                         finish_consuming_dead_subbuffer(instance->callbacks, buf);
 371                         break;
 372                 }
 373
 374                 if(instance->callbacks->on_read_subbuffer)
 375                         instance->callbacks->on_read_subbuffer(instance->callbacks, buf);
 376
 377                 /* put the subbuffer */
 378                 result = put_subbuffer(buf);
 379                 if(result == -1) {
 380                         ERR("unknown error putting subbuffer (channel=%s)", buf->name);
 381                         break;
 382                 }
 383                 else if(result == PUT_SUBBUF_PUSHED) {
 384                         ERR("Buffer overflow (channel=%s), reader pushed. This channel will not be usable passed this point.", buf->name);
 385                         break;
 386                 }
 387                 else if(result == PUT_SUBBUF_DIED) {
 388                         DBG("application died while putting subbuffer");
 389                         /* Skip the first subbuffer. We are not sure it is trustable
 390                          * because the put_subbuffer() did not complete.
 391                          */
 392                         if(instance->callbacks->on_put_error)
 393                                 instance->callbacks->on_put_error(instance->callbacks, buf);
 394
 395                         finish_consuming_dead_subbuffer(instance->callbacks, buf);
 396                         break;
 397                 }
 398                 else if(result == PUT_SUBBUF_DONE) {
 399                         /* Done with this subbuffer */
 400                         /* FIXME: add a case where this branch is used? Upon
 401                          * normal trace termination, at put_subbuf time, a
 402                          * special last-subbuffer code could be returned by
 403                          * the listener.
 404                          */
 405                         break;
 406                 }
 407                 else if(result == PUT_SUBBUF_OK) {
 408                 }
 409         }
 410
 411         DBG("thread for buffer %s is stopping", buf->name);
 412
 413         /* FIXME: destroy, unalloc... */
 414
 415         pthread_cleanup_pop(1);
 416
 417         return 0;
 418 }
 419
 420 struct consumer_thread_args {
 421         pid_t pid;
 422         const char *bufname;
 423         struct libustd_instance *instance;
 424 };
 425
 426 void *consumer_thread(void *arg)
 427 {
 428         struct buffer_info *buf;
 429         struct consumer_thread_args *args = (struct consumer_thread_args *) arg;
 430         int result;
 431         sigset_t sigset;
 432
 433         DBG("GOT ARGS: pid %d bufname %s", args->pid, args->bufname);
 434
 435         if(args->instance->callbacks->on_new_thread)
 436                 args->instance->callbacks->on_new_thread(args->instance->callbacks);
 437
 438         /* Block signals that should be handled by the main thread. */
 439         result = sigemptyset(&sigset);
 440         if(result == -1) {
 441                 PERROR("sigemptyset");
 442                 goto end;
 443         }
 444         result = sigaddset(&sigset, SIGTERM);
 445         if(result == -1) {
 446                 PERROR("sigaddset");
 447                 goto end;
 448         }
 449         result = sigaddset(&sigset, SIGINT);
 450         if(result == -1) {
 451                 PERROR("sigaddset");
 452                 goto end;
 453         }
 454         result = sigprocmask(SIG_BLOCK, &sigset, NULL);
 455         if(result == -1) {
 456                 PERROR("sigprocmask");
 457                 goto end;
 458         }
 459
 460         buf = connect_buffer(args->instance, args->pid, args->bufname);
 461         if(buf == NULL) {
 462                 ERR("failed to connect to buffer");
 463                 goto end;
 464         }
 465
 466         consumer_loop(args->instance, buf);
 467
 468         destroy_buffer(args->instance->callbacks, buf);
 469
 470         end:
 471
 472         if(args->instance->callbacks->on_close_thread)
 473                 args->instance->callbacks->on_close_thread(args->instance->callbacks);
 474
 475         free((void *)args->bufname);
 476         free(args);
 477         return NULL;
 478 }
 479
 480 int start_consuming_buffer(
 481         struct libustd_instance *instance, pid_t pid, const char *bufname)
 482 {
 483         pthread_t thr;
 484         struct consumer_thread_args *args;
 485         int result;
 486
 487         DBG("beginning of start_consuming_buffer: args: pid %d bufname %s", pid, bufname);
 488
 489         args = (struct consumer_thread_args *) malloc(sizeof(struct consumer_thread_args));
 490
 491         args->pid = pid;
 492         args->bufname = strdup(bufname);
 493         args->instance = instance;
 494         DBG("beginning2 of start_consuming_buffer: args: pid %d bufname %s", args->pid, args->bufname);
 495
 496         result = pthread_create(&thr, NULL, consumer_thread, args);
 497         if(result == -1) {
 498                 ERR("pthread_create failed");
 499                 return -1;
 500         }
 501         result = pthread_detach(thr);
 502         if(result == -1) {
 503                 ERR("pthread_detach failed");
 504                 return -1;
 505         }
 506         DBG("end of start_consuming_buffer: args: pid %d bufname %s", args->pid, args->bufname);
 507
 508         return 0;
 509 }
 510
 511 int libustd_start_instance(struct libustd_instance *instance)
 512 {
 513         int result;
 514         int timeout = -1;
 515
 516         if(!instance->is_init) {
 517                 ERR("libustd instance not initialized");
 518                 return 1;
 519         }
 520
 521         /* app loop */
 522         for(;;) {
 523                 char *recvbuf;
 524
 525                 /* check for requests on our public socket */
 526                 result = ustcomm_ustd_recv_message(&instance->comm, &recvbuf, NULL, timeout);
 527                 if(result == -1 && errno == EINTR) {
 528                         /* Caught signal */
 529                 }
 530                 else if(result == -1) {
 531                         ERR("error in ustcomm_ustd_recv_message");
 532                         goto loop_end;
 533                 }
 534                 else if(result > 0) {
 535                         if(!strncmp(recvbuf, "collect", 7)) {
 536                                 pid_t pid;
 537                                 char *bufname;
 538                                 int result;
 539
 540                                 result = sscanf(recvbuf, "%*s %d %50as", &pid, &bufname);
 541                                 if(result != 2) {
 542                                         ERR("parsing error: %s", recvbuf);
 543                                         goto free_bufname;
 544                                 }
 545
 546                                 result = start_consuming_buffer(instance, pid, bufname);
 547                                 if(result < 0) {
 548                                         ERR("error in add_buffer");
 549                                         goto free_bufname;
 550                                 }
 551
 552                                 free_bufname:
 553                                 free(bufname);
 554                         }
 555                         else if(!strncmp(recvbuf, "exit", 4)) {
 556                                 /* Only there to force poll to return */
 557                         }
 558                         else {
 559                                 WARN("unknown command: %s", recvbuf);
 560                         }
 561
 562                         free(recvbuf);
 563                 }
 564
 565                 loop_end:
 566
 567                 if(instance->quit_program) {
 568                         pthread_mutex_lock(&instance->mutex);
 569                         if(instance->active_buffers == 0) {
 570                                 pthread_mutex_unlock(&instance->mutex);
 571                                 break;
 572                         }
 573                         pthread_mutex_unlock(&instance->mutex);
 574                         timeout = 100;
 575                 }
 576         }
 577
 578         if(instance->callbacks->on_trace_end)
 579                 instance->callbacks->on_trace_end(instance);
 580
 581         libustd_delete_instance(instance);
 582
 583         return 0;
 584 }
 585
 586 void libustd_delete_instance(struct libustd_instance *instance)
 587 {
 588         if(instance->is_init)
 589                 ustcomm_fini_ustd(&instance->comm);
 590
 591         pthread_mutex_destroy(&instance->mutex);
 592         free(instance->sock_path);
 593         free(instance);
 594 }
 595
 596 int libustd_stop_instance(struct libustd_instance *instance, int send_msg)
 597 {
 598         int result;
 599         int fd;
 600         int bytes = 0;
 601
 602         char msg[] = "exit";
 603
 604         instance->quit_program = 1;
 605
 606         if(!send_msg)
 607                 return 0;
 608
 609         /* Send a message through the socket to force poll to return */
 610
 611         struct sockaddr_un addr;
 612
 613         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 614         if(result == -1) {
 615                 PERROR("socket");
 616                 return 1;
 617         }
 618
 619         addr.sun_family = AF_UNIX;
 620
 621         strncpy(addr.sun_path, instance->sock_path, UNIX_PATH_MAX);
 622         addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 623
 624         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 625         if(result == -1) {
 626                 PERROR("connect");
 627         }
 628
 629         while(bytes != sizeof(msg))
 630                 bytes += send(fd, msg, sizeof(msg), 0);
 631
 632         close(fd);
 633
 634         return 0;
 635 }
 636
 637 struct libustd_instance *libustd_new_instance(
 638         struct libustd_callbacks *callbacks, char *sock_path)
 639 {
 640         struct libustd_instance *instance =
 641                 malloc(sizeof(struct libustd_instance));
 642         if(!instance)
 643                 return NULL;
 644
 645         instance->callbacks = callbacks;
 646         instance->quit_program = 0;
 647         instance->is_init = 0;
 648         instance->active_buffers = 0;
 649         pthread_mutex_init(&instance->mutex, NULL);
 650
 651         if(sock_path)
 652                 instance->sock_path = strdup(sock_path);
 653         else
 654                 instance->sock_path = NULL;
 655
 656         return instance;
 657 }
 658
 659 int libustd_init_instance(struct libustd_instance *instance)
 660 {
 661         int result;
 662         result = ustcomm_init_ustd(&instance->comm, instance->sock_path);
 663         if(result == -1) {
 664                 ERR("failed to initialize socket");
 665                 return 1;
 666         }
 667         instance->is_init = 1;
 668         return 0;
 669 }
 670