ustd/ustd.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 #define _GNU_SOURCE
  19
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22 #include <sys/shm.h>
  23 #include <fcntl.h>
  24 #include <unistd.h>
  25 #include <pthread.h>
  26 #include <signal.h>
  27
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <errno.h>
  32 #include <assert.h>
  33 #include <getopt.h>
  34
  35 #include "ustd.h"
  36 #include "usterr.h"
  37 #include "ustcomm.h"
  38
  39 /* return value: 0 = subbuffer is finished, it won't produce data anymore
  40  *               1 = got subbuffer successfully
  41  *               <0 = error
  42  */
  43
  44 #define GET_SUBBUF_OK 1
  45 #define GET_SUBBUF_DONE 0
  46 #define GET_SUBBUF_DIED 2
  47
  48 #define PUT_SUBBUF_OK 1
  49 #define PUT_SUBBUF_DIED 0
  50 #define PUT_SUBBUF_PUSHED 2
  51 #define PUT_SUBBUF_DONE 3
  52
  53 char *sock_path=NULL;
  54 char *trace_path=NULL;
  55 int daemon_mode = 0;
  56 char *pidfile = NULL;
  57
  58 /* Number of active buffers and the mutex to protect it. */
  59 int active_buffers = 0;
  60 pthread_mutex_t active_buffers_mutex = PTHREAD_MUTEX_INITIALIZER;
  61 /* Whether a request to end the program was received. */
  62 volatile sig_atomic_t terminate_req = 0;
  63
  64 int get_subbuffer(struct buffer_info *buf)
  65 {
  66         char *send_msg=NULL;
  67         char *received_msg=NULL;
  68         char *rep_code=NULL;
  69         int retval;
  70         int result;
  71
  72         asprintf(&send_msg, "get_subbuffer %s", buf->name);
  73         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
  74         if((result == -1 && (errno == ECONNRESET || errno == EPIPE)) || result == 0) {
  75                 DBG("app died while being traced");
  76                 retval = GET_SUBBUF_DIED;
  77                 goto end;
  78         }
  79         else if(result < 0) {
  80                 ERR("get_subbuffer: ustcomm_send_request failed");
  81                 retval = -1;
  82                 goto end;
  83         }
  84
  85         result = sscanf(received_msg, "%as %ld", &rep_code, &buf->consumed_old);
  86         if(result != 2 && result != 1) {
  87                 ERR("unable to parse response to get_subbuffer");
  88                 retval = -1;
  89                 free(received_msg);
  90                 goto end_rep;
  91         }
  92
  93         if(!strcmp(rep_code, "OK")) {
  94                 DBG("got subbuffer %s", buf->name);
  95                 retval = GET_SUBBUF_OK;
  96         }
  97         else if(nth_token_is(received_msg, "END", 0) == 1) {
  98                 retval = GET_SUBBUF_DONE;
  99                 goto end_rep;
 100         }
 101         else if(!strcmp(received_msg, "NOTFOUND")) {
 102                 DBG("For buffer %s, the trace was not found. This likely means it was destroyed by the user.", buf->name);
 103                 retval = GET_SUBBUF_DIED;
 104                 goto end_rep;
 105         }
 106         else {
 107                 DBG("error getting subbuffer %s", buf->name);
 108                 retval = -1;
 109         }
 110
 111         /* FIMXE: free correctly the stuff */
 112 end_rep:
 113         if(rep_code)
 114                 free(rep_code);
 115 end:
 116         if(send_msg)
 117                 free(send_msg);
 118         if(received_msg)
 119                 free(received_msg);
 120
 121         return retval;
 122 }
 123
 124 int put_subbuffer(struct buffer_info *buf)
 125 {
 126         char *send_msg=NULL;
 127         char *received_msg=NULL;
 128         char *rep_code=NULL;
 129         int retval;
 130         int result;
 131
 132         asprintf(&send_msg, "put_subbuffer %s %ld", buf->name, buf->consumed_old);
 133         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 134         if(result < 0 && (errno == ECONNRESET || errno == EPIPE)) {
 135                 retval = PUT_SUBBUF_DIED;
 136                 goto end;
 137         }
 138         else if(result < 0) {
 139                 ERR("put_subbuffer: send_message failed");
 140                 retval = -1;
 141                 goto end;
 142         }
 143         else if(result == 0) {
 144                 /* Program seems finished. However this might not be
 145                  * the last subbuffer that has to be collected.
 146                  */
 147                 retval = PUT_SUBBUF_DIED;
 148                 goto end;
 149         }
 150
 151         result = sscanf(received_msg, "%as", &rep_code);
 152         if(result != 1) {
 153                 ERR("unable to parse response to put_subbuffer");
 154                 retval = -1;
 155                 goto end_rep;
 156         }
 157
 158         if(!strcmp(rep_code, "OK")) {
 159                 DBG("subbuffer put %s", buf->name);
 160                 retval = PUT_SUBBUF_OK;
 161         }
 162         else if(!strcmp(received_msg, "NOTFOUND")) {
 163                 DBG("For buffer %s, the trace was not found. This likely means it was destroyed by the user.", buf->name);
 164                 /* However, maybe this was not the last subbuffer. So
 165                  * we return the program died.
 166                  */
 167                 retval = PUT_SUBBUF_DIED;
 168                 goto end_rep;
 169         }
 170         else {
 171                 DBG("put_subbuffer: received error, we were pushed");
 172                 retval = PUT_SUBBUF_PUSHED;
 173                 goto end_rep;
 174         }
 175
 176 end_rep:
 177         if(rep_code)
 178                 free(rep_code);
 179
 180 end:
 181         if(send_msg)
 182                 free(send_msg);
 183         if(received_msg)
 184                 free(received_msg);
 185
 186         return retval;
 187 }
 188
 189 void decrement_active_buffers(void *arg)
 190 {
 191         pthread_mutex_lock(&active_buffers_mutex);
 192         active_buffers--;
 193         pthread_mutex_unlock(&active_buffers_mutex);
 194 }
 195
 196 int create_dir_if_needed(char *dir)
 197 {
 198         int result;
 199         result = mkdir(dir, 0777);
 200         if(result == -1) {
 201                 if(errno != EEXIST) {
 202                         PERROR("mkdir");
 203                         return -1;
 204                 }
 205         }
 206
 207         return 0;
 208 }
 209
 210 int is_directory(const char *dir)
 211 {
 212         int result;
 213         struct stat st;
 214
 215         result = stat(dir, &st);
 216         if(result == -1) {
 217                 PERROR("stat");
 218                 return 0;
 219         }
 220
 221         if(!S_ISDIR(st.st_mode)) {
 222                 return 0;
 223         }
 224
 225         return 1;
 226 }
 227
 228 struct buffer_info *connect_buffer(pid_t pid, const char *bufname)
 229 {
 230         struct buffer_info *buf;
 231         char *send_msg;
 232         char *received_msg;
 233         int result;
 234         char *tmp;
 235         int fd;
 236         struct shmid_ds shmds;
 237
 238         buf = (struct buffer_info *) malloc(sizeof(struct buffer_info));
 239         if(buf == NULL) {
 240                 ERR("add_buffer: insufficient memory");
 241                 return NULL;
 242         }
 243
 244         buf->name = bufname;
 245         buf->pid = pid;
 246
 247         /* connect to app */
 248         result = ustcomm_connect_app(buf->pid, &buf->conn);
 249         if(result) {
 250                 WARN("unable to connect to process, it probably died before we were able to connect");
 251                 return NULL;
 252         }
 253
 254         /* get pidunique */
 255         asprintf(&send_msg, "get_pidunique");
 256         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 257         free(send_msg);
 258         if(result == -1) {
 259                 ERR("problem in ustcomm_send_request(get_pidunique)");
 260                 return NULL;
 261         }
 262         if(result == 0) {
 263                 goto error;
 264         }
 265
 266         result = sscanf(received_msg, "%lld", &buf->pidunique);
 267         if(result != 1) {
 268                 ERR("unable to parse response to get_pidunique");
 269                 return NULL;
 270         }
 271         free(received_msg);
 272         DBG("got pidunique %lld", buf->pidunique);
 273
 274         /* get shmid */
 275         asprintf(&send_msg, "get_shmid %s", buf->name);
 276         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 277         free(send_msg);
 278         if(result == -1) {
 279                 ERR("problem in ustcomm_send_request(get_shmid)");
 280                 return NULL;
 281         }
 282         if(result == 0) {
 283                 goto error;
 284         }
 285
 286         result = sscanf(received_msg, "%d %d", &buf->shmid, &buf->bufstruct_shmid);
 287         if(result != 2) {
 288                 ERR("unable to parse response to get_shmid (\"%s\")", received_msg);
 289                 return NULL;
 290         }
 291         free(received_msg);
 292         DBG("got shmids %d %d", buf->shmid, buf->bufstruct_shmid);
 293
 294         /* get n_subbufs */
 295         asprintf(&send_msg, "get_n_subbufs %s", buf->name);
 296         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 297         free(send_msg);
 298         if(result == -1) {
 299                 ERR("problem in ustcomm_send_request(g_n_subbufs)");
 300                 return NULL;
 301         }
 302         if(result == 0) {
 303                 goto error;
 304         }
 305
 306         result = sscanf(received_msg, "%d", &buf->n_subbufs);
 307         if(result != 1) {
 308                 ERR("unable to parse response to get_n_subbufs");
 309                 return NULL;
 310         }
 311         free(received_msg);
 312         DBG("got n_subbufs %d", buf->n_subbufs);
 313
 314         /* get subbuf size */
 315         asprintf(&send_msg, "get_subbuf_size %s", buf->name);
 316         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 317         free(send_msg);
 318         if(result == -1) {
 319                 ERR("problem in ustcomm_send_request(get_subbuf_size)");
 320                 return NULL;
 321         }
 322         if(result == 0) {
 323                 goto error;
 324         }
 325
 326         result = sscanf(received_msg, "%d", &buf->subbuf_size);
 327         if(result != 1) {
 328                 ERR("unable to parse response to get_subbuf_size");
 329                 return NULL;
 330         }
 331         free(received_msg);
 332         DBG("got subbuf_size %d", buf->subbuf_size);
 333
 334         /* attach memory */
 335         buf->mem = shmat(buf->shmid, NULL, 0);
 336         if(buf->mem == (void *) 0) {
 337                 PERROR("shmat");
 338                 return NULL;
 339         }
 340         DBG("successfully attached buffer memory");
 341
 342         buf->bufstruct_mem = shmat(buf->bufstruct_shmid, NULL, 0);
 343         if(buf->bufstruct_mem == (void *) 0) {
 344                 PERROR("shmat");
 345                 return NULL;
 346         }
 347         DBG("successfully attached buffer bufstruct memory");
 348
 349         /* obtain info on the memory segment */
 350         result = shmctl(buf->shmid, IPC_STAT, &shmds);
 351         if(result == -1) {
 352                 PERROR("shmctl");
 353                 return NULL;
 354         }
 355         buf->memlen = shmds.shm_segsz;
 356
 357         /* open file for output */
 358         if(!trace_path) {
 359                 /* Only create the directory if using the default path, because
 360                  * of the risk of typo when using trace path override. We don't
 361                  * want to risk creating plenty of useless directories in that case.
 362                  */
 363                 result = create_dir_if_needed(USTD_DEFAULT_TRACE_PATH);
 364                 if(result == -1) {
 365                         ERR("could not create directory %s", USTD_DEFAULT_TRACE_PATH);
 366                         return NULL;
 367                 }
 368
 369                 trace_path = USTD_DEFAULT_TRACE_PATH;
 370         }
 371
 372         asprintf(&tmp, "%s/%u_%lld", trace_path, buf->pid, buf->pidunique);
 373         result = create_dir_if_needed(tmp);
 374         if(result == -1) {
 375                 ERR("could not create directory %s", tmp);
 376                 free(tmp);
 377                 return NULL;
 378         }
 379         free(tmp);
 380
 381         asprintf(&tmp, "%s/%u_%lld/%s", trace_path, buf->pid, buf->pidunique, buf->name);
 382         result = fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 00600);
 383         if(result == -1) {
 384                 PERROR("open");
 385                 ERR("failed opening trace file %s", tmp);
 386                 return NULL;
 387         }
 388         buf->file_fd = fd;
 389         free(tmp);
 390
 391         pthread_mutex_lock(&active_buffers_mutex);
 392         active_buffers++;
 393         pthread_mutex_unlock(&active_buffers_mutex);
 394
 395         return buf;
 396
 397 error:
 398         free(buf);
 399         return NULL;
 400 }
 401
 402 static void destroy_buffer(struct buffer_info *buf)
 403 {
 404         int result;
 405
 406         result = ustcomm_close_app(&buf->conn);
 407         if(result == -1) {
 408                 WARN("problem calling ustcomm_close_app");
 409         }
 410
 411         result = shmdt(buf->mem);
 412         if(result == -1) {
 413                 PERROR("shmdt");
 414         }
 415
 416         result = shmdt(buf->bufstruct_mem);
 417         if(result == -1) {
 418                 PERROR("shmdt");
 419         }
 420
 421         result = close(buf->file_fd);
 422         if(result == -1) {
 423                 PERROR("close");
 424         }
 425
 426         free(buf);
 427 }
 428
 429 int unwrite_last_subbuffer(struct buffer_info *buf)
 430 {
 431         int result;
 432
 433         result = ftruncate(buf->file_fd, buf->previous_offset);
 434         if(result == -1) {
 435                 PERROR("ftruncate");
 436                 return -1;
 437         }
 438
 439         result = lseek(buf->file_fd, buf->previous_offset, SEEK_SET);
 440         if(result == (int)(off_t)-1) {
 441                 PERROR("lseek");
 442                 return -1;
 443         }
 444
 445         return 0;
 446 }
 447
 448 int write_current_subbuffer(struct buffer_info *buf)
 449 {
 450         int result;
 451
 452         void *subbuf_mem = buf->mem + (buf->consumed_old & (buf->n_subbufs * buf->subbuf_size-1));
 453
 454         size_t cur_sb_size = subbuffer_data_size(subbuf_mem);
 455
 456         off_t cur_offset = lseek(buf->file_fd, 0, SEEK_CUR);
 457         if(cur_offset == (off_t)-1) {
 458                 PERROR("lseek");
 459                 return -1;
 460         }
 461
 462         buf->previous_offset = cur_offset;
 463         DBG("previous_offset: %ld", cur_offset);
 464
 465         result = patient_write(buf->file_fd, subbuf_mem, cur_sb_size);
 466         if(result == -1) {
 467                 PERROR("write");
 468                 /* FIXME: maybe drop this trace */
 469                 return -1;
 470         }
 471
 472         return 0;
 473 }
 474
 475 int consumer_loop(struct buffer_info *buf)
 476 {
 477         int result;
 478
 479         pthread_cleanup_push(decrement_active_buffers, NULL);
 480
 481         for(;;) {
 482                 /* get the subbuffer */
 483                 result = get_subbuffer(buf);
 484                 if(result == -1) {
 485                         ERR("error getting subbuffer");
 486                         continue;
 487                 }
 488                 else if(result == GET_SUBBUF_DONE) {
 489                         /* this is done */
 490                         break;
 491                 }
 492                 else if(result == GET_SUBBUF_DIED) {
 493                         finish_consuming_dead_subbuffer(buf);
 494                         break;
 495                 }
 496
 497                 /* write data to file */
 498                 write_current_subbuffer(buf);
 499                 /* FIXME: handle return value? */
 500
 501                 /* put the subbuffer */
 502                 result = put_subbuffer(buf);
 503                 if(result == -1) {
 504                         ERR("unknown error putting subbuffer (channel=%s)", buf->name);
 505                         break;
 506                 }
 507                 else if(result == PUT_SUBBUF_PUSHED) {
 508                         ERR("Buffer overflow (channel=%s), reader pushed. This channel will not be usable passed this point.", buf->name);
 509                         break;
 510                 }
 511                 else if(result == PUT_SUBBUF_DIED) {
 512                         DBG("application died while putting subbuffer");
 513                         /* Skip the first subbuffer. We are not sure it is trustable
 514                          * because the put_subbuffer() did not complete.
 515                          */
 516                         unwrite_last_subbuffer(buf);
 517                         finish_consuming_dead_subbuffer(buf);
 518                         break;
 519                 }
 520                 else if(result == PUT_SUBBUF_DONE) {
 521                         /* Done with this subbuffer */
 522                         /* FIXME: add a case where this branch is used? Upon
 523                          * normal trace termination, at put_subbuf time, a
 524                          * special last-subbuffer code could be returned by
 525                          * the listener.
 526                          */
 527                         break;
 528                 }
 529                 else if(result == PUT_SUBBUF_OK) {
 530                 }
 531         }
 532
 533         DBG("thread for buffer %s is stopping", buf->name);
 534
 535         /* FIXME: destroy, unalloc... */
 536
 537         pthread_cleanup_pop(1);
 538
 539         return 0;
 540 }
 541
 542 struct consumer_thread_args {
 543         pid_t pid;
 544         const char *bufname;
 545 };
 546
 547 void *consumer_thread(void *arg)
 548 {
 549         struct buffer_info *buf = (struct buffer_info *) arg;
 550         struct consumer_thread_args *args = (struct consumer_thread_args *) arg;
 551
 552         DBG("GOT ARGS: pid %d bufname %s", args->pid, args->bufname);
 553
 554         buf = connect_buffer(args->pid, args->bufname);
 555         if(buf == NULL) {
 556                 ERR("failed to connect to buffer");
 557                 goto end;
 558         }
 559
 560         consumer_loop(buf);
 561
 562         free((void *)args->bufname);
 563         destroy_buffer(buf);
 564
 565         end:
 566         free(args);
 567         return NULL;
 568 }
 569
 570 int start_consuming_buffer(pid_t pid, const char *bufname)
 571 {
 572         pthread_t thr;
 573         struct consumer_thread_args *args;
 574         int result;
 575
 576         DBG("beginning of start_consuming_buffer: args: pid %d bufname %s", pid, bufname);
 577
 578         args = (struct consumer_thread_args *) malloc(sizeof(struct consumer_thread_args));
 579
 580         args->pid = pid;
 581         args->bufname = strdup(bufname);
 582         DBG("beginning2 of start_consuming_buffer: args: pid %d bufname %s", args->pid, args->bufname);
 583
 584         result = pthread_create(&thr, NULL, consumer_thread, args);
 585         if(result == -1) {
 586                 ERR("pthread_create failed");
 587                 return -1;
 588         }
 589         result = pthread_detach(thr);
 590         if(result == -1) {
 591                 ERR("pthread_detach failed");
 592                 return -1;
 593         }
 594         DBG("end of start_consuming_buffer: args: pid %d bufname %s", args->pid, args->bufname);
 595
 596         return 0;
 597 }
 598
 599 void usage(void)
 600 {
 601         fprintf(stderr, "Usage:\nustd OPTIONS\n\nOptions:\n"
 602                         "\t-h\t\tDisplay this usage.\n"
 603                         "\t-o DIR\t\tSpecify the directory where to output the traces.\n"
 604                         "\t-s PATH\t\tSpecify the path to use for the daemon socket.\n"
 605                         "\t-d\t\tStart as a daemon.\n"
 606                         "\t--pidfile FILE\tWrite the PID in this file (when using -d).\n");
 607 }
 608
 609 int parse_args(int argc, char **argv)
 610 {
 611         int c;
 612
 613         while (1) {
 614                 int option_index = 0;
 615                 static struct option long_options[] = {
 616                         {"pidfile", 1, 0, 'p'},
 617                         {"help", 0, 0, 'h'},
 618                         {"version", 0, 0, 'V'},
 619                         {0, 0, 0, 0}
 620                 };
 621
 622                 c = getopt_long(argc, argv, "hs:o:d", long_options, &option_index);
 623                 if (c == -1)
 624                         break;
 625
 626                 switch (c) {
 627                 case 0:
 628                         printf("option %s", long_options[option_index].name);
 629                         if (optarg)
 630                                 printf(" with arg %s", optarg);
 631                         printf("\n");
 632                         break;
 633                 case 's':
 634                         sock_path = optarg;
 635                         break;
 636                 case 'o':
 637                         trace_path = optarg;
 638                         if(!is_directory(trace_path)) {
 639                                 ERR("Not a valid directory. (%s)", trace_path);
 640                                 return -1;
 641                         }
 642                         break;
 643                 case 'd':
 644                         daemon_mode = 1;
 645                         break;
 646                 case 'p':
 647                         pidfile = strdup(optarg);
 648                         break;
 649                 case 'h':
 650                         usage();
 651                         exit(0);
 652                 case 'V':
 653                         printf("Version 0.0\n");
 654                         break;
 655
 656                 default:
 657                         /* unknown option or other error; error is
 658                         printed by getopt, just return */
 659                         return -1;
 660                 }
 661         }
 662
 663         return 0;
 664 }
 665
 666 void sigterm_handler(int sig)
 667 {
 668         terminate_req = 1;
 669 }
 670
 671 static int write_pidfile(const char *file_name, pid_t pid)
 672 {
 673         FILE *pidfp;
 674
 675         pidfp = fopen(file_name, "w");
 676         if(!pidfp) {
 677                 PERROR("fopen (%s)", pidfile);
 678                 WARN("killing child process");
 679                 return -1;
 680         }
 681
 682         fprintf(pidfp, "%d\n", pid);
 683
 684         fclose(pidfp);
 685
 686         return 0;
 687 }
 688
 689 int start_ustd(int fd)
 690 {
 691         struct ustcomm_ustd ustd;
 692         int result;
 693         sigset_t sigset;
 694         struct sigaction sa;
 695
 696         result = sigemptyset(&sigset);
 697         if(result == -1) {
 698                 PERROR("sigemptyset");
 699                 return 1;
 700         }
 701         sa.sa_handler = sigterm_handler;
 702         sa.sa_mask = sigset;
 703         sa.sa_flags = SA_RESTART;
 704         result = sigaction(SIGTERM, &sa, NULL);
 705         if(result == -1) {
 706                 PERROR("sigaction");
 707                 return 1;
 708         }
 709         result = sigaction(SIGINT, &sa, NULL);
 710         if(result == -1) {
 711                 PERROR("sigaction");
 712                 return 1;
 713         }
 714
 715         result = ustcomm_init_ustd(&ustd, sock_path);
 716         if(result == -1) {
 717                 ERR("failed to initialize socket");
 718                 return 1;
 719         }
 720
 721         /* setup handler for SIGPIPE */
 722         result = sigemptyset(&sigset);
 723         if(result == -1) {
 724                 PERROR("sigemptyset");
 725                 return 1;
 726         }
 727         result = sigaddset(&sigset, SIGPIPE);
 728         if(result == -1) {
 729                 PERROR("sigaddset");
 730                 return 1;
 731         }
 732         result = sigprocmask(SIG_BLOCK, &sigset, NULL);
 733         if(result == -1) {
 734                 PERROR("sigprocmask");
 735                 return 1;
 736         }
 737
 738         /* Write pidfile */
 739         if(pidfile) {
 740                 result = write_pidfile(pidfile, getpid());
 741                 if(result == -1) {
 742                         ERR("failed to write pidfile");
 743                         return 1;
 744                 }
 745         }
 746
 747         /* Notify parent that we are successfully started. */
 748         if(fd != -1) {
 749                 /* write any one character */
 750                 result = write(fd, "!", 1);
 751                 if(result == -1) {
 752                         PERROR("write");
 753                         return -1;
 754                 }
 755                 if(result != 1) {
 756                         ERR("Problem sending confirmation of daemon start to parent");
 757                         return -1;
 758                 }
 759                 result = close(fd);
 760                 if(result == -1) {
 761                         PERROR("close");
 762                 }
 763         }
 764
 765         /* app loop */
 766         for(;;) {
 767                 char *recvbuf;
 768
 769                 /* check for requests on our public socket */
 770                 result = ustcomm_ustd_recv_message(&ustd, &recvbuf, NULL, 100);
 771                 if(result == -1) {
 772                         ERR("error in ustcomm_ustd_recv_message");
 773                         goto loop_end;
 774                 }
 775                 if(result > 0) {
 776                         if(!strncmp(recvbuf, "collect", 7)) {
 777                                 pid_t pid;
 778                                 char *bufname;
 779                                 int result;
 780
 781                                 result = sscanf(recvbuf, "%*s %d %50as", &pid, &bufname);
 782                                 if(result != 2) {
 783                                         ERR("parsing error: %s", recvbuf);
 784                                         goto free_bufname;
 785                                 }
 786
 787                                 result = start_consuming_buffer(pid, bufname);
 788                                 if(result < 0) {
 789                                         ERR("error in add_buffer");
 790                                         goto free_bufname;
 791                                 }
 792
 793                                 free_bufname:
 794                                 free(bufname);
 795                         }
 796                         else {
 797                                 WARN("unknown command: %s", recvbuf);
 798                         }
 799
 800                         free(recvbuf);
 801                 }
 802
 803                 loop_end:
 804
 805                 if(terminate_req) {
 806                         pthread_mutex_lock(&active_buffers_mutex);
 807                         if(active_buffers == 0) {
 808                                 pthread_mutex_unlock(&active_buffers_mutex);
 809                                 break;
 810                         }
 811                         pthread_mutex_unlock(&active_buffers_mutex);
 812                 }
 813         }
 814
 815         ustcomm_fini_ustd(&ustd);
 816
 817         return 0;
 818 }
 819
 820 int start_ustd_daemon()
 821 {
 822         int result;
 823         int fd[2];
 824         pid_t child_pid;
 825
 826         result = pipe(fd);
 827
 828         result = child_pid = fork();
 829         if(result == -1) {
 830                 PERROR("fork");
 831                 return -1;
 832         }
 833         else if(result == 0) {
 834                 return start_ustd(fd[1]);
 835         }
 836         else {
 837                 char buf;
 838
 839                 result = read(fd[0], &buf, 1);
 840                 if(result == -1) {
 841                         PERROR("read");
 842                         return -1;
 843                 }
 844                 if(result != 1) {
 845                         ERR("did not receive valid confirmation that the daemon is started");
 846                         return -1;
 847                 }
 848
 849                 result = close(fd[0]);
 850                 if(result == -1) {
 851                         PERROR("close");
 852                 }
 853
 854                 DBG("The daemon is now successfully started");
 855         }
 856
 857         /* Wait for confirmation that the server is ready. */
 858
 859
 860         return 0;
 861 }
 862
 863 int main(int argc, char **argv)
 864 {
 865         int result;
 866
 867         result = parse_args(argc, argv);
 868         if(result == -1) {
 869                 exit(1);
 870         }
 871
 872         if(daemon_mode) {
 873                 result = start_ustd_daemon();
 874         }
 875         else {
 876                 result = start_ustd(-1);
 877         }
 878
 879         return result;
 880 }