ltt/branches/poly/lttd/lttd.c

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