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 #define _GNU_SOURCE
  14 #include <config.h>
  15 #include <stdio.h>
  16 #include <unistd.h>
  17 #include <errno.h>
  18 #include <sys/types.h>
  19 #include <sys/stat.h>
  20 #include <stdlib.h>
  21 #include <dirent.h>
  22 #include <string.h>
  23 #include <fcntl.h>
  24 #include <sys/poll.h>
  25 #include <sys/mman.h>
  26 #include <signal.h>
  27
  28 /* Relayfs IOCTL */
  29 #include <asm/ioctl.h>
  30 #include <asm/types.h>
  31
  32 /* Get the next sub buffer that can be read. */
  33 #define RELAYFS_GET_SUBBUF        _IOR(0xF4, 0x00,__u32)
  34 /* Release the oldest reserved (by "get") sub buffer. */
  35 #define RELAYFS_PUT_SUBBUF        _IO(0xF4, 0x01)
  36 /* returns the number of sub buffers in the per cpu channel. */
  37 #define RELAYFS_GET_N_SUBBUFS     _IOR(0xF4, 0x02,__u32)
  38 /* returns the size of the sub buffers. */
  39 #define RELAYFS_GET_SUBBUF_SIZE   _IOR(0xF4, 0x03,__u32)
  40
  41
  42
  43 enum {
  44         GET_SUBBUF,
  45         PUT_SUBBUF,
  46         GET_N_BUBBUFS,
  47         GET_SUBBUF_SIZE
  48 };
  49
  50 struct fd_pair {
  51         int channel;
  52         int trace;
  53         unsigned int n_subbufs;
  54         unsigned int subbuf_size;
  55         void *mmap;
  56 };
  57
  58 struct channel_trace_fd {
  59         struct fd_pair *pair;
  60         int num_pairs;
  61 };
  62
  63 static char *trace_name = NULL;
  64 static char *channel_name = NULL;
  65 static int      daemon_mode = 0;
  66 static int      append_mode = 0;
  67 static int      sig_parent = 0;
  68 volatile static int     quit_program = 0;       /* For signal handler */
  69
  70 /* Args :
  71  *
  72  * -t directory         Directory name of the trace to write to. Will be created.
  73  * -c directory         Root directory of the relayfs trace channels.
  74  * -d                   Run in background (daemon).
  75  * -a                                                   Trace append mode.
  76  * -s                                                   Send SIGIO to parent when ready for IO.
  77  */
  78 void show_arguments(void)
  79 {
  80         printf("Please use the following arguments :\n");
  81         printf("\n");
  82         printf("-t directory  Directory name of the trace to write to.\n"
  83                                  "              It will be created.\n");
  84         printf("-c directory  Root directory of the relayfs trace channels.\n");
  85         printf("-d            Run in background (daemon).\n");
  86         printf("-a            Append to an possibly existing trace.\n");
  87         printf("-s            Send SIGIO to parent when ready for IO.\n");
  88         printf("\n");
  89 }
  90
  91
  92 /* parse_arguments
  93  *
  94  * Parses the command line arguments.
  95  *
  96  * Returns 1 if the arguments were correct, but doesn't ask for program
  97  * continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
  98  */
  99 int parse_arguments(int argc, char **argv)
 100 {
 101         int ret = 0;
 102         int argn = 1;
 103
 104         if(argc == 2) {
 105                 if(strcmp(argv[1], "-h") == 0) {
 106                         return 1;
 107                 }
 108         }
 109
 110         while(argn < argc) {
 111
 112                 switch(argv[argn][0]) {
 113                         case '-':
 114                                 switch(argv[argn][1]) {
 115                                         case 't':
 116                                                 if(argn+1 < argc) {
 117                                                         trace_name = argv[argn+1];
 118                                                         argn++;
 119                                                 }
 120                                                 break;
 121                                         case 'c':
 122                                                 if(argn+1 < argc) {
 123                                                         channel_name = argv[argn+1];
 124                                                         argn++;
 125                                                 }
 126                                                 break;
 127                                         case 'd':
 128                                                 daemon_mode = 1;
 129                                                 break;
 130                                         case 'a':
 131                                                 append_mode = 1;
 132                                                 break;
 133                                         case 's':
 134                                                 sig_parent = 1;
 135                                                 break;
 136                                         default:
 137                                                 printf("Invalid argument '%s'.\n", argv[argn]);
 138                                                 printf("\n");
 139                                                 ret = -1;
 140                                 }
 141                                 break;
 142                         default:
 143                                 printf("Invalid argument '%s'.\n", argv[argn]);
 144                                 printf("\n");
 145                                 ret = -1;
 146                 }
 147                 argn++;
 148         }
 149
 150         if(trace_name == NULL) {
 151                 printf("Please specify a trace name.\n");
 152                 printf("\n");
 153                 ret = -1;
 154         }
 155
 156         if(channel_name == NULL) {
 157                 printf("Please specify a channel name.\n");
 158                 printf("\n");
 159                 ret = -1;
 160         }
 161
 162         return ret;
 163 }
 164
 165 void show_info(void)
 166 {
 167         printf("Linux Trace Toolkit Trace Daemon\n");
 168         printf("\n");
 169         printf("Reading from relayfs directory : %s\n", channel_name);
 170         printf("Writing to trace directory : %s\n", trace_name);
 171         printf("\n");
 172 }
 173
 174
 175 /* signal handling */
 176
 177 static void handler(int signo)
 178 {
 179         printf("Signal %d received : exiting cleanly\n", signo);
 180         quit_program = 1;
 181 }
 182
 183
 184
 185 int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
 186                 struct channel_trace_fd *fd_pairs)
 187 {
 188         DIR *channel_dir = opendir(subchannel_name);
 189         struct dirent *entry;
 190         struct stat stat_buf;
 191         int ret;
 192         char path_channel[PATH_MAX];
 193         int path_channel_len;
 194         char *path_channel_ptr;
 195         char path_trace[PATH_MAX];
 196         int path_trace_len;
 197         char *path_trace_ptr;
 198
 199         if(channel_dir == NULL) {
 200                 perror(subchannel_name);
 201                 return ENOENT;
 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 && append_mode) {
 208                         printf("Appending to directory %s as resquested\n", subtrace_name);
 209                 } else {
 210                         perror(subtrace_name);
 211                         return -1;
 212                 }
 213         }
 214
 215         strncpy(path_channel, subchannel_name, PATH_MAX-1);
 216         path_channel_len = strlen(path_channel);
 217         path_channel[path_channel_len] = '/';
 218         path_channel_len++;
 219         path_channel_ptr = path_channel + path_channel_len;
 220
 221         strncpy(path_trace, subtrace_name, PATH_MAX-1);
 222         path_trace_len = strlen(path_trace);
 223         path_trace[path_trace_len] = '/';
 224         path_trace_len++;
 225         path_trace_ptr = path_trace + path_trace_len;
 226
 227         while((entry = readdir(channel_dir)) != NULL) {
 228
 229                 if(entry->d_name[0] == '.') continue;
 230
 231                 strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
 232                 strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
 233
 234                 ret = stat(path_channel, &stat_buf);
 235                 if(ret == -1) {
 236                         perror(path_channel);
 237                         continue;
 238                 }
 239
 240                 printf("Channel file : %s\n", path_channel);
 241
 242                 if(S_ISDIR(stat_buf.st_mode)) {
 243
 244                         printf("Entering channel subdirectory...\n");
 245                         ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
 246                         if(ret < 0) continue;
 247                 } else if(S_ISREG(stat_buf.st_mode)) {
 248                         printf("Opening file.\n");
 249
 250                         fd_pairs->pair = realloc(fd_pairs->pair,
 251                                         ++fd_pairs->num_pairs * sizeof(struct fd_pair));
 252
 253                         /* Open the channel in read mode */
 254                         fd_pairs->pair[fd_pairs->num_pairs-1].channel =
 255                                 open(path_channel, O_RDONLY | O_NONBLOCK);
 256                         if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
 257                                 perror(path_channel);
 258                                 fd_pairs->num_pairs--;
 259                                 continue;
 260                         }
 261                         /* Open the trace in write mode, only append if append_mode */
 262                         ret = stat(path_trace, &stat_buf);
 263                         if(ret == 0) {
 264                                 if(append_mode) {
 265                                         printf("Appending to file %s as requested\n", path_trace);
 266
 267                                         fd_pairs->pair[fd_pairs->num_pairs-1].trace =
 268                                                 open(path_trace, O_WRONLY|O_APPEND,
 269                                                                 S_IRWXU|S_IRWXG|S_IRWXO);
 270
 271                                         if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
 272                                                 perror(path_trace);
 273                                         }
 274                                 } else {
 275                                         printf("File %s exists, cannot open. Try append mode.\n", path_trace);
 276                                         return -1;
 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         closedir(channel_dir);
 292
 293         return 0;
 294 }
 295
 296
 297 int read_subbuffer(struct fd_pair *pair)
 298 {
 299         unsigned int    subbuf_index;
 300         int err, ret;
 301
 302
 303         err = ioctl(pair->channel, RELAYFS_GET_SUBBUF,
 304                                                                 &subbuf_index);
 305         printf("index : %u\n", subbuf_index);
 306         if(err != 0) {
 307                 perror("Error in reserving sub buffer");
 308                 ret = -EPERM;
 309                 goto get_error;
 310         }
 311
 312         err = TEMP_FAILURE_RETRY(write(pair->trace,
 313                                 pair->mmap + (subbuf_index * pair->subbuf_size),
 314                                 pair->subbuf_size));
 315
 316         if(err < 0) {
 317                 perror("Error in writing to file");
 318                 ret = err;
 319                 goto write_error;
 320         }
 321
 322
 323 write_error:
 324         err = ioctl(pair->channel, RELAYFS_PUT_SUBBUF);
 325         if(err != 0) {
 326                 perror("Error in unreserving sub buffer");
 327                 ret = -EPERM;
 328                 goto get_error;
 329         }
 330
 331 get_error:
 332         return ret;
 333 }
 334
 335
 336 /* read_channels
 337  *
 338  * Read the realyfs channels and write them in the paired tracefiles.
 339  *
 340  * @fd_pairs : paired channels and trace files.
 341  *
 342  * returns 0 on success, -1 on error.
 343  *
 344  * Note that the high priority polled channels are consumed first. We then poll
 345  * again to see if these channels are still in priority. Only when no
 346  * high priority channel is left, we start reading low priority channels.
 347  *
 348  * Note that a channel is considered high priority when the buffer is almost
 349  * full.
 350  */
 351
 352 int read_channels(struct channel_trace_fd *fd_pairs)
 353 {
 354         struct pollfd *pollfd;
 355         int i,j;
 356         int num_rdy, num_hup;
 357         int high_prio;
 358         int ret;
 359
 360         if(fd_pairs->num_pairs <= 0) {
 361                 printf("No channel to read\n");
 362                 goto end;
 363         }
 364
 365         /* Get the subbuf sizes and number */
 366
 367         for(i=0;i<fd_pairs->num_pairs;i++) {
 368                 struct fd_pair *pair = &fd_pairs->pair[i];
 369
 370                 ret = ioctl(pair->channel, RELAYFS_GET_N_SUBBUFS,
 371                                                         &pair->n_subbufs);
 372                 if(ret != 0) {
 373                         perror("Error in getting the number of subbuffers");
 374                         goto end;
 375                 }
 376                 ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF_SIZE,
 377                                                         &pair->subbuf_size);
 378                 if(ret != 0) {
 379                         perror("Error in getting the size of the subbuffers");
 380                         goto end;
 381                 }
 382         }
 383
 384         /* Mmap each FD */
 385         for(i=0;i<fd_pairs->num_pairs;i++) {
 386                 struct fd_pair *pair = &fd_pairs->pair[i];
 387
 388                 pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
 389                                 MAP_SHARED, pair->channel, 0);
 390                 if(pair->mmap == MAP_FAILED) {
 391                         perror("Mmap error");
 392                         goto munmap;
 393                 }
 394         }
 395
 396
 397         /* Start polling the FD */
 398
 399         pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));
 400
 401         /* Note : index in pollfd is the same index as fd_pair->pair */
 402         for(i=0;i<fd_pairs->num_pairs;i++) {
 403                 pollfd[i].fd = fd_pairs->pair[i].channel;
 404                 pollfd[i].events = POLLIN|POLLPRI;
 405         }
 406
 407         /* Signal the parent that ready for IO */
 408         if(sig_parent) kill(getppid(), SIGIO);
 409
 410         while(1) {
 411                 high_prio = 0;
 412                 num_hup = 0;
 413 #ifdef DEBUG
 414                 printf("Press a key for next poll...\n");
 415                 char buf[1];
 416                 read(STDIN_FILENO, &buf, 1);
 417                 printf("Next poll (polling %d fd) :\n", fd_pairs->num_pairs);
 418 #endif //DEBUG
 419
 420                 /* Have we received a signal ? */
 421                 if(quit_program) break;
 422
 423                 num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
 424                 if(num_rdy == -1) {
 425                         perror("Poll error");
 426                         goto free_fd;
 427                 }
 428
 429                 printf("Data received\n");
 430
 431                 for(i=0;i<fd_pairs->num_pairs;i++) {
 432                         switch(pollfd[i].revents) {
 433                                 case POLLERR:
 434                                         printf("Error returned in polling fd %d.\n", pollfd[i].fd);
 435                                         num_hup++;
 436                                         break;
 437                                 case POLLHUP:
 438                                         printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
 439                                         num_hup++;
 440                                         break;
 441                                 case POLLNVAL:
 442                                         printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
 443                                         num_hup++;
 444                                         break;
 445                                 case POLLPRI:
 446                                         printf("Urgent read on fd %d\n", pollfd[i].fd);
 447                                         /* Take care of high priority channels first. */
 448                                         high_prio = 1;
 449                                         ret |= read_subbuffer(&fd_pairs->pair[i]);
 450                                         break;
 451                         }
 452                 }
 453                 /* If every FD has hung up, we end the read loop here */
 454                 if(num_hup == fd_pairs->num_pairs) break;
 455
 456                 if(!high_prio) {
 457                         for(i=0;i<fd_pairs->num_pairs;i++) {
 458                                 switch(pollfd[i].revents) {
 459                                         case POLLIN:
 460                                                 /* Take care of low priority channels. */
 461                                                 printf("Normal read on fd %d\n", pollfd[i].fd);
 462                                                 ret |= read_subbuffer(&fd_pairs->pair[i]);
 463                                                 break;
 464                                 }
 465                         }
 466                 }
 467
 468         }
 469
 470 free_fd:
 471         free(pollfd);
 472
 473         /* munmap only the successfully mmapped indexes */
 474         i = fd_pairs->num_pairs;
 475 munmap:
 476                 /* Munmap each FD */
 477         for(j=0;j<i;j++) {
 478                 struct fd_pair *pair = &fd_pairs->pair[j];
 479                 int err_ret;
 480
 481                 err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
 482                 if(err_ret != 0) {
 483                         perror("Error in munmap");
 484                 }
 485                 ret |= err_ret;
 486         }
 487
 488 end:
 489         return ret;
 490 }
 491
 492
 493 void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
 494 {
 495         int i;
 496         int ret;
 497
 498         for(i=0;i<fd_pairs->num_pairs;i++) {
 499                 ret = close(fd_pairs->pair[i].channel);
 500                 if(ret == -1) perror("Close error on channel");
 501                 ret = close(fd_pairs->pair[i].trace);
 502                 if(ret == -1) perror("Close error on trace");
 503         }
 504         free(fd_pairs->pair);
 505 }
 506
 507 int main(int argc, char ** argv)
 508 {
 509         int ret;
 510         pid_t pid;
 511         struct channel_trace_fd fd_pairs = { NULL, 0 };
 512         struct sigaction act;
 513
 514         ret = parse_arguments(argc, argv);
 515
 516         if(ret != 0) show_arguments();
 517         if(ret < 0) return EINVAL;
 518         if(ret > 0) return 0;
 519
 520         show_info();
 521
 522         if(daemon_mode) {
 523                 pid = fork();
 524
 525                 if(pid > 0) {
 526                         /* parent */
 527                         return 0;
 528                 } else if(pid < 0) {
 529                         /* error */
 530                         printf("An error occured while forking.\n");
 531                         return -1;
 532                 }
 533                 /* else, we are the child, continue... */
 534         }
 535
 536         /* Connect the signal handlers */
 537         act.sa_handler = handler;
 538         act.sa_flags = 0;
 539         sigemptyset(&(act.sa_mask));
 540         sigaddset(&(act.sa_mask), SIGTERM);
 541         sigaddset(&(act.sa_mask), SIGQUIT);
 542         sigaddset(&(act.sa_mask), SIGINT);
 543         sigaction(SIGTERM, &act, NULL);
 544         sigaction(SIGQUIT, &act, NULL);
 545         sigaction(SIGINT, &act, NULL);
 546
 547         //return 0;
 548         if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
 549                 goto close_channel;
 550
 551         ret = read_channels(&fd_pairs);
 552
 553 close_channel:
 554         close_channel_trace_pairs(&fd_pairs);
 555
 556         return ret;
 557 }