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