trunk/attic/lttng-xenomai/ltt-control-0.24-xenoltt/lttd/lttd.c

   1 /* lttd
   2  *
   3  * Linux Trace Toolkit Daemon
   4  *
   5  * This is a simple daemon that reads a few relay+debugfs channels and save
   6  * them in a trace.
   7  *
   8  *
   9  * Copyright 2005 -
  10  *      Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  11  */
  12
  13 #ifdef HAVE_CONFIG_H
  14 #include <config.h>
  15 #endif
  16
  17 #define _REENTRANT
  18 #define _GNU_SOURCE
  19 #include <features.h>
  20 #include <stdio.h>
  21 #include <unistd.h>
  22 #include <errno.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <stdlib.h>
  26 #include <dirent.h>
  27 #include <string.h>
  28 #include <fcntl.h>
  29 #include <sys/poll.h>
  30 #include <sys/mman.h>
  31 #include <signal.h>
  32 #include <pthread.h>
  33
  34 /* Relayfs IOCTL */
  35 #include <asm/ioctl.h>
  36 #include <asm/types.h>
  37
  38 /* Get the next sub buffer that can be read. */
  39 #define RELAY_GET_SUBBUF        _IOR(0xF4, 0x00,__u32)
  40 /* Release the oldest reserved (by "get") sub buffer. */
  41 #define RELAY_PUT_SUBBUF        _IOW(0xF4, 0x01,__u32)
  42 /* returns the number of sub buffers in the per cpu channel. */
  43 #define RELAY_GET_N_SUBBUFS     _IOR(0xF4, 0x02,__u32)
  44 /* returns the size of the sub buffers. */
  45 #define RELAY_GET_SUBBUF_SIZE   _IOR(0xF4, 0x03,__u32)
  46
  47
  48
  49 enum {
  50         GET_SUBBUF,
  51         PUT_SUBBUF,
  52         GET_N_BUBBUFS,
  53         GET_SUBBUF_SIZE
  54 };
  55
  56 struct fd_pair {
  57         int channel;
  58         int trace;
  59         unsigned int n_subbufs;
  60         unsigned int subbuf_size;
  61         void *mmap;
  62         pthread_mutex_t mutex;
  63 };
  64
  65 struct channel_trace_fd {
  66         struct fd_pair *pair;
  67         int num_pairs;
  68 };
  69
  70 static char             *trace_name = NULL;
  71 static char             *channel_name = NULL;
  72 static int              daemon_mode = 0;
  73 static int              append_mode = 0;
  74 static unsigned long    num_threads = 1;
  75 volatile static int     quit_program = 0;       /* For signal handler */
  76 static int              dump_flight_only = 0;
  77 static int              dump_normal_only = 0;
  78
  79 /* Args :
  80  *
  81  * -t directory         Directory name of the trace to write to. Will be created.
  82  * -c directory         Root directory of the debugfs trace channels.
  83  * -d                   Run in background (daemon).
  84  * -a                                                   Trace append mode.
  85  * -s                                                   Send SIGUSR1 to parent when ready for IO.
  86  */
  87 void show_arguments(void)
  88 {
  89         printf("Please use the following arguments :\n");
  90         printf("\n");
  91         printf("-t directory  Directory name of the trace to write to.\n"
  92                                  "              It will be created.\n");
  93         printf("-c directory  Root directory of the debugfs trace channels.\n");
  94         printf("-d            Run in background (daemon).\n");
  95         printf("-a            Append to an possibly existing trace.\n");
  96         printf("-N            Number of threads to start.\n");
  97         printf("-f            Dump only flight recorder channels.\n");
  98         printf("-n            Dump only normal channels.\n");
  99         printf("\n");
 100 }
 101
 102
 103 /* parse_arguments
 104  *
 105  * Parses the command line arguments.
 106  *
 107  * Returns 1 if the arguments were correct, but doesn't ask for program
 108  * continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
 109  */
 110 int parse_arguments(int argc, char **argv)
 111 {
 112         int ret = 0;
 113         int argn = 1;
 114
 115         if(argc == 2) {
 116                 if(strcmp(argv[1], "-h") == 0) {
 117                         return 1;
 118                 }
 119         }
 120
 121         while(argn < argc) {
 122
 123                 switch(argv[argn][0]) {
 124                         case '-':
 125                                 switch(argv[argn][1]) {
 126                                         case 't':
 127                                                 if(argn+1 < argc) {
 128                                                         trace_name = argv[argn+1];
 129                                                         argn++;
 130                                                 }
 131                                                 break;
 132                                         case 'c':
 133                                                 if(argn+1 < argc) {
 134                                                         channel_name = argv[argn+1];
 135                                                         argn++;
 136                                                 }
 137                                                 break;
 138                                         case 'd':
 139                                                 daemon_mode = 1;
 140                                                 break;
 141                                         case 'a':
 142                                                 append_mode = 1;
 143                                                 break;
 144                                         case 'N':
 145                                                 if(argn+1 < argc) {
 146                                                         num_threads = strtoul(argv[argn+1], NULL, 0);
 147                                                         argn++;
 148                                                 }
 149                                                 break;
 150                                         case 'f':
 151                                                 dump_flight_only = 1;
 152                                                 break;
 153                                         case 'n':
 154                                                 dump_normal_only = 1;
 155                                                 break;
 156                                         default:
 157                                                 printf("Invalid argument '%s'.\n", argv[argn]);
 158                                                 printf("\n");
 159                                                 ret = -1;
 160                                 }
 161                                 break;
 162                         default:
 163                                 printf("Invalid argument '%s'.\n", argv[argn]);
 164                                 printf("\n");
 165                                 ret = -1;
 166                 }
 167                 argn++;
 168         }
 169
 170         if(trace_name == NULL) {
 171                 printf("Please specify a trace name.\n");
 172                 printf("\n");
 173                 ret = -1;
 174         }
 175
 176         if(channel_name == NULL) {
 177                 printf("Please specify a channel name.\n");
 178                 printf("\n");
 179                 ret = -1;
 180         }
 181
 182         return ret;
 183 }
 184
 185 void show_info(void)
 186 {
 187         printf("Linux Trace Toolkit Trace Daemon\n");
 188         printf("\n");
 189         printf("Reading from debugfs directory : %s\n", channel_name);
 190         printf("Writing to trace directory : %s\n", trace_name);
 191         printf("\n");
 192 }
 193
 194
 195 /* signal handling */
 196
 197 static void handler(int signo)
 198 {
 199         printf("Signal %d received : exiting cleanly\n", signo);
 200         quit_program = 1;
 201 }
 202
 203
 204
 205 int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
 206                 struct channel_trace_fd *fd_pairs)
 207 {
 208         DIR *channel_dir = opendir(subchannel_name);
 209         struct dirent *entry;
 210         struct stat stat_buf;
 211         int ret;
 212         char path_channel[PATH_MAX];
 213         int path_channel_len;
 214         char *path_channel_ptr;
 215         char path_trace[PATH_MAX];
 216         int path_trace_len;
 217         char *path_trace_ptr;
 218         int open_ret = 0;
 219
 220         if(channel_dir == NULL) {
 221                 perror(subchannel_name);
 222                 open_ret = ENOENT;
 223                 goto end;
 224         }
 225
 226         printf("Creating trace subdirectory %s\n", subtrace_name);
 227         ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO);
 228         if(ret == -1) {
 229                 if(errno != EEXIST) {
 230                         perror(subtrace_name);
 231                         open_ret = -1;
 232                         goto end;
 233                 }
 234         }
 235
 236         strncpy(path_channel, subchannel_name, PATH_MAX-1);
 237         path_channel_len = strlen(path_channel);
 238         path_channel[path_channel_len] = '/';
 239         path_channel_len++;
 240         path_channel_ptr = path_channel + path_channel_len;
 241
 242         strncpy(path_trace, subtrace_name, PATH_MAX-1);
 243         path_trace_len = strlen(path_trace);
 244         path_trace[path_trace_len] = '/';
 245         path_trace_len++;
 246         path_trace_ptr = path_trace + path_trace_len;
 247
 248         while((entry = readdir(channel_dir)) != NULL) {
 249
 250                 if(entry->d_name[0] == '.') continue;
 251
 252                 strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
 253                 strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
 254
 255                 ret = stat(path_channel, &stat_buf);
 256                 if(ret == -1) {
 257                         perror(path_channel);
 258                         continue;
 259                 }
 260
 261                 printf("Channel file : %s\n", path_channel);
 262
 263                 if(S_ISDIR(stat_buf.st_mode)) {
 264
 265                         printf("Entering channel subdirectory...\n");
 266                         ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
 267                         if(ret < 0) continue;
 268                 } else if(S_ISREG(stat_buf.st_mode)) {
 269                         if(strncmp(entry->d_name, "flight-", sizeof("flight-")-1) != 0) {
 270                                 if(dump_flight_only) {
 271                                         printf("Skipping normal channel %s\n", path_channel);
 272                                         continue;
 273                                 }
 274                         } else {
 275                                 if(dump_normal_only) {
 276                                         printf("Skipping flight channel %s\n", path_channel);
 277                                         continue;
 278                                 }
 279                         }
 280                         printf("Opening file.\n");
 281
 282                         fd_pairs->pair = realloc(fd_pairs->pair,
 283                                         ++fd_pairs->num_pairs * sizeof(struct fd_pair));
 284
 285                         /* Open the channel in read mode */
 286                         fd_pairs->pair[fd_pairs->num_pairs-1].channel =
 287                                 open(path_channel, O_RDONLY | O_NONBLOCK);
 288                         if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
 289                                 perror(path_channel);
 290                                 fd_pairs->num_pairs--;
 291                                 continue;
 292                         }
 293                         /* Open the trace in write mode, only append if append_mode */
 294                         ret = stat(path_trace, &stat_buf);
 295                         if(ret == 0) {
 296                                 if(append_mode) {
 297                                         printf("Appending to file %s as requested\n", path_trace);
 298
 299                                         fd_pairs->pair[fd_pairs->num_pairs-1].trace =
 300                                                 open(path_trace, O_WRONLY|O_APPEND,
 301                                                                 S_IRWXU|S_IRWXG|S_IRWXO);
 302
 303                                         if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
 304                                                 perror(path_trace);
 305                                         }
 306                                 } else {
 307                                         printf("File %s exists, cannot open. Try append mode.\n", path_trace);
 308                                         open_ret = -1;
 309                                         goto end;
 310                                 }
 311                         } else {
 312                                 if(errno == ENOENT) {
 313                                         fd_pairs->pair[fd_pairs->num_pairs-1].trace =
 314                                                 open(path_trace, O_WRONLY|O_CREAT|O_EXCL,
 315                                                                 S_IRWXU|S_IRWXG|S_IRWXO);
 316                                         if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
 317                                                 perror(path_trace);
 318                                         }
 319                                 }
 320                         }
 321                 }
 322         }
 323
 324 end:
 325         closedir(channel_dir);
 326
 327         return open_ret;
 328 }
 329
 330
 331 int read_subbuffer(struct fd_pair *pair)
 332 {
 333         unsigned int    consumed_old;
 334         int err, ret=0;
 335
 336
 337         err = ioctl(pair->channel, RELAY_GET_SUBBUF,
 338                                                                 &consumed_old);
 339         printf("cookie : %u\n", consumed_old);
 340         if(err != 0) {
 341                 ret = errno;
 342                 perror("Reserving sub buffer failed (everything is normal, it is due to concurrency)");
 343                 goto get_error;
 344         }
 345
 346         err = TEMP_FAILURE_RETRY(write(pair->trace,
 347                                 pair->mmap
 348                                         + (consumed_old & ((pair->n_subbufs * pair->subbuf_size)-1)),
 349                                 pair->subbuf_size));
 350
 351         if(err < 0) {
 352                 ret = errno;
 353                 perror("Error in writing to file");
 354                 goto write_error;
 355         }
 356 #if 0
 357         err = fsync(pair->trace);
 358         if(err < 0) {
 359                 ret = errno;
 360                 perror("Error in writing to file");
 361                 goto write_error;
 362         }
 363 #endif //0
 364 write_error:
 365         err = ioctl(pair->channel, RELAY_PUT_SUBBUF, &consumed_old);
 366         if(err != 0) {
 367                 ret = errno;
 368                 if(errno == EFAULT) {
 369                         perror("Error in unreserving sub buffer\n");
 370                 } else if(errno == EIO) {
 371                         perror("Reader has been pushed by the writer, last subbuffer corrupted.");
 372                         /* FIXME : we may delete the last written buffer if we wish. */
 373                 }
 374                 goto get_error;
 375         }
 376
 377 get_error:
 378         return ret;
 379 }
 380
 381
 382
 383 int map_channels(struct channel_trace_fd *fd_pairs)
 384 {
 385         int i,j;
 386         int ret=0;
 387
 388         if(fd_pairs->num_pairs <= 0) {
 389                 printf("No channel to read\n");
 390                 goto end;
 391         }
 392
 393         /* Get the subbuf sizes and number */
 394
 395         for(i=0;i<fd_pairs->num_pairs;i++) {
 396                 struct fd_pair *pair = &fd_pairs->pair[i];
 397
 398                 ret = ioctl(pair->channel, RELAY_GET_N_SUBBUFS,
 399                                                         &pair->n_subbufs);
 400                 if(ret != 0) {
 401                         perror("Error in getting the number of subbuffers");
 402                         goto end;
 403                 }
 404                 ret = ioctl(pair->channel, RELAY_GET_SUBBUF_SIZE,
 405                                                         &pair->subbuf_size);
 406                 if(ret != 0) {
 407                         perror("Error in getting the size of the subbuffers");
 408                         goto end;
 409                 }
 410                 ret = pthread_mutex_init(&pair->mutex, NULL);   /* Fast mutex */
 411                 if(ret != 0) {
 412                         perror("Error in mutex init");
 413                         goto end;
 414                 }
 415         }
 416
 417         /* Mmap each FD */
 418         for(i=0;i<fd_pairs->num_pairs;i++) {
 419                 struct fd_pair *pair = &fd_pairs->pair[i];
 420
 421                 pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
 422                                 MAP_SHARED, pair->channel, 0);
 423                 if(pair->mmap == MAP_FAILED) {
 424                         perror("Mmap error");
 425                         goto munmap;
 426                 }
 427         }
 428
 429         goto end; /* success */
 430
 431         /* Error handling */
 432         /* munmap only the successfully mmapped indexes */
 433 munmap:
 434                 /* Munmap each FD */
 435         for(j=0;j<i;j++) {
 436                 struct fd_pair *pair = &fd_pairs->pair[j];
 437                 int err_ret;
 438
 439                 err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
 440                 if(err_ret != 0) {
 441                         perror("Error in munmap");
 442                 }
 443                 ret |= err_ret;
 444         }
 445
 446 end:
 447         return ret;
 448
 449
 450 }
 451
 452
 453 int unmap_channels(struct channel_trace_fd *fd_pairs)
 454 {
 455         int j;
 456         int ret=0;
 457
 458         /* Munmap each FD */
 459         for(j=0;j<fd_pairs->num_pairs;j++) {
 460                 struct fd_pair *pair = &fd_pairs->pair[j];
 461                 int err_ret;
 462
 463                 err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
 464                 if(err_ret != 0) {
 465                         perror("Error in munmap");
 466                 }
 467                 ret |= err_ret;
 468                 err_ret = pthread_mutex_destroy(&pair->mutex);
 469                 if(err_ret != 0) {
 470                         perror("Error in mutex destroy");
 471                 }
 472                 ret |= err_ret;
 473         }
 474
 475         return ret;
 476 }
 477
 478
 479 /* read_channels
 480  *
 481  * Thread worker.
 482  *
 483  * Read the debugfs channels and write them in the paired tracefiles.
 484  *
 485  * @fd_pairs : paired channels and trace files.
 486  *
 487  * returns (void*)0 on success, (void*)-1 on error.
 488  *
 489  * Note that the high priority polled channels are consumed first. We then poll
 490  * again to see if these channels are still in priority. Only when no
 491  * high priority channel is left, we start reading low priority channels.
 492  *
 493  * Note that a channel is considered high priority when the buffer is almost
 494  * full.
 495  */
 496
 497 void * read_channels(void *arg)
 498 {
 499         struct pollfd *pollfd;
 500         int i,j;
 501         int num_rdy, num_hup;
 502         int high_prio;
 503         int ret = 0;
 504         struct channel_trace_fd *fd_pairs = (struct channel_trace_fd *)arg;
 505
 506         /* Start polling the FD */
 507
 508         pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));
 509
 510         /* Note : index in pollfd is the same index as fd_pair->pair */
 511         for(i=0;i<fd_pairs->num_pairs;i++) {
 512                 pollfd[i].fd = fd_pairs->pair[i].channel;
 513                 pollfd[i].events = POLLIN|POLLPRI;
 514         }
 515
 516         while(1) {
 517                 high_prio = 0;
 518                 num_hup = 0;
 519 #ifdef DEBUG
 520                 printf("Press a key for next poll...\n");
 521                 char buf[1];
 522                 read(STDIN_FILENO, &buf, 1);
 523                 printf("Next poll (polling %d fd) :\n", fd_pairs->num_pairs);
 524 #endif //DEBUG
 525
 526                 /* Have we received a signal ? */
 527                 if(quit_program) break;
 528
 529                 num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
 530                 if(num_rdy == -1) {
 531                         perror("Poll error");
 532                         goto free_fd;
 533                 }
 534
 535                 printf("Data received\n");
 536
 537                 for(i=0;i<fd_pairs->num_pairs;i++) {
 538                         switch(pollfd[i].revents) {
 539                                 case POLLERR:
 540                                         printf("Error returned in polling fd %d.\n", pollfd[i].fd);
 541                                         num_hup++;
 542                                         break;
 543                                 case POLLHUP:
 544                                         printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
 545                                         num_hup++;
 546                                         break;
 547                                 case POLLNVAL:
 548                                         printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
 549                                         num_hup++;
 550                                         break;
 551                                 case POLLPRI:
 552                                         if(pthread_mutex_trylock(&fd_pairs->pair[i].mutex) == 0) {
 553                                                 printf("Urgent read on fd %d\n", pollfd[i].fd);
 554                                                 /* Take care of high priority channels first. */
 555                                                 high_prio = 1;
 556                                                 /* it's ok to have an unavailable subbuffer */
 557                                                 ret = read_subbuffer(&fd_pairs->pair[i]);
 558                                                 if(ret == EAGAIN) ret = 0;
 559
 560                                                 ret = pthread_mutex_unlock(&fd_pairs->pair[i].mutex);
 561                                                 if(ret)
 562                                                         printf("Error in mutex unlock : %s\n", strerror(ret));
 563                                         }
 564                                         break;
 565                         }
 566                 }
 567                 /* If every FD has hung up, we end the read loop here */
 568                 if(num_hup == fd_pairs->num_pairs) break;
 569
 570                 if(!high_prio) {
 571                         for(i=0;i<fd_pairs->num_pairs;i++) {
 572                                 switch(pollfd[i].revents) {
 573                                         case POLLIN:
 574                                                 if(pthread_mutex_trylock(&fd_pairs->pair[i].mutex) == 0) {
 575                                                         /* Take care of low priority channels. */
 576                                                         printf("Normal read on fd %d\n", pollfd[i].fd);
 577                                                         /* it's ok to have an unavailable subbuffer */
 578                                                         ret = read_subbuffer(&fd_pairs->pair[i]);
 579                                                         if(ret == EAGAIN) ret = 0;
 580
 581                                                         ret = pthread_mutex_unlock(&fd_pairs->pair[i].mutex);
 582                                                         if(ret)
 583                                                                 printf("Error in mutex unlock : %s\n", strerror(ret));
 584                                                 }
 585                                                 break;
 586                                 }
 587                         }
 588                 }
 589
 590         }
 591
 592 free_fd:
 593         free(pollfd);
 594
 595 end:
 596         return (void*)ret;
 597 }
 598
 599
 600 void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
 601 {
 602         int i;
 603         int ret;
 604
 605         for(i=0;i<fd_pairs->num_pairs;i++) {
 606                 ret = close(fd_pairs->pair[i].channel);
 607                 if(ret == -1) perror("Close error on channel");
 608                 ret = close(fd_pairs->pair[i].trace);
 609                 if(ret == -1) perror("Close error on trace");
 610         }
 611         free(fd_pairs->pair);
 612 }
 613
 614 int main(int argc, char ** argv)
 615 {
 616         int ret = 0;
 617         struct channel_trace_fd fd_pairs = { NULL, 0 };
 618         struct sigaction act;
 619         pthread_t *tids;
 620         unsigned int i;
 621         void *tret;
 622
 623         ret = parse_arguments(argc, argv);
 624
 625         if(ret != 0) show_arguments();
 626         if(ret < 0) return EINVAL;
 627         if(ret > 0) return 0;
 628
 629         show_info();
 630
 631         if(daemon_mode) {
 632                 ret = daemon(0, 0);
 633
 634                 if(ret == -1) {
 635                         perror("An error occured while daemonizing.");
 636                         exit(-1);
 637                 }
 638         }
 639
 640         /* Connect the signal handlers */
 641         act.sa_handler = handler;
 642         act.sa_flags = 0;
 643         sigemptyset(&(act.sa_mask));
 644         sigaddset(&(act.sa_mask), SIGTERM);
 645         sigaddset(&(act.sa_mask), SIGQUIT);
 646         sigaddset(&(act.sa_mask), SIGINT);
 647         sigaction(SIGTERM, &act, NULL);
 648         sigaction(SIGQUIT, &act, NULL);
 649         sigaction(SIGINT, &act, NULL);
 650
 651
 652         if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
 653                 goto close_channel;
 654
 655         if(ret = map_channels(&fd_pairs))
 656                 goto close_channel;
 657
 658         tids = malloc(sizeof(pthread_t) * num_threads);
 659         for(i=0; i<num_threads; i++) {
 660                 ret = pthread_create(&tids[i], NULL, read_channels, &fd_pairs);
 661                 if(ret) {
 662                         perror("Error creating thread");
 663                         break;
 664                 }
 665         }
 666
 667         for(i=0; i<num_threads; i++) {
 668                 ret = pthread_join(tids[i], &tret);
 669                 if(ret) {
 670                         perror("Error joining thread");
 671                         break;
 672                 }
 673                 if((int)tret != 0) {
 674                         printf("Error %s occured in thread %u\n", strerror((int)tret), i);
 675                 }
 676         }
 677
 678         free(tids);
 679
 680         ret |= unmap_channels(&fd_pairs);
 681
 682 close_channel:
 683         close_channel_trace_pairs(&fd_pairs);
 684
 685         return ret;
 686 }