tests/ust-basic-tracing/ust-basic-tracing.c

   1 /*
   2  * ust-basic-tracing.c - Basic single-session, single-channel, single-process UST tracing
   3  *
   4  * Copyright (C) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; version 2 of the License only.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #define _LARGEFILE64_SOURCE
  22 #define _GNU_SOURCE
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <signal.h>
  28 #include <unistd.h>
  29 #include <sys/wait.h>
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <sys/time.h>
  33 #include <sys/resource.h>
  34 #include <fcntl.h>
  35 #include <sys/mman.h>
  36 #include <limits.h>
  37 #include <urcu/futex.h>
  38 #include <urcu/uatomic.h>
  39 #include <assert.h>
  40 #include <sys/socket.h>
  41
  42 #include <ust-comm.h>
  43 #include <lttng/ust-error.h>
  44 #include "../../libringbuffer/backend.h"
  45 #include "../../libringbuffer/frontend.h"
  46 #include "../../liblttng-ust/compat.h"  /* For ENODATA */
  47
  48 #define MAX_NR_STREAMS  64
  49 #define MAX_NR_EVENTS   128
  50
  51 static int session_handle;
  52 static struct lttng_ust_object_data metadata_stream_data;
  53 static struct lttng_ust_object_data metadata_data;
  54 static struct lttng_ust_object_data channel_data;
  55 static struct lttng_ust_object_data stream_data[MAX_NR_STREAMS];
  56 static int event_handle[MAX_NR_EVENTS];
  57 static int context_handle;
  58
  59 static int apps_socket = -1;
  60 static char apps_sock_path[PATH_MAX];
  61 static char local_apps_wait_shm_path[PATH_MAX];
  62
  63 static volatile int quit_program;
  64
  65 static void handle_signals(int signo)
  66 {
  67         quit_program = 1;
  68 }
  69
  70 static
  71 int open_streams(int sock, int channel_handle, struct lttng_ust_object_data *stream_datas,
  72                 int nr_check)
  73 {
  74         int ret, k = 0;
  75
  76         for (;;) {
  77                 struct ustcomm_ust_msg lum;
  78                 struct ustcomm_ust_reply lur;
  79
  80                 memset(&lum, 0, sizeof(lum));
  81                 lum.handle = channel_handle;
  82                 lum.cmd = LTTNG_UST_STREAM;
  83                 ret = ustcomm_send_app_cmd(sock, &lum, &lur);
  84                 if (!ret) {
  85                         assert(k < nr_check);
  86                         stream_datas[k].handle = lur.ret_val;
  87                         printf("received stream handle %u\n",
  88                                 stream_datas[k].handle);
  89                         if (lur.ret_code == LTTNG_UST_OK) {
  90                                 ssize_t len;
  91
  92                                 stream_datas[k].memory_map_size = lur.u.stream.memory_map_size;
  93                                 /* get shm fd */
  94                                 len = ustcomm_recv_fd(sock);
  95                                 if (len < 0)
  96                                         return -EINVAL;
  97                                 stream_datas[k].shm_fd = len;
  98                                 /* get wait fd */
  99                                 len = ustcomm_recv_fd(sock);
 100                                 if (len < 0)
 101                                         return -EINVAL;
 102                                 stream_datas[k].wait_fd = len;
 103                         }
 104                         k++;
 105                 }
 106                 if (ret == -LTTNG_UST_ERR_NOENT)
 107                         break;
 108                 if (ret)
 109                         return ret;
 110         }
 111         return 0;
 112 }
 113
 114 static
 115 int close_streams(int sock, struct lttng_ust_object_data *stream_datas, int nr_check)
 116 {
 117         int ret, k;
 118
 119         for (k = 0; k < nr_check; k++) {
 120                 struct ustcomm_ust_msg lum;
 121                 struct ustcomm_ust_reply lur;
 122
 123                 if (!stream_datas[k].handle)
 124                         continue;
 125                 memset(&lum, 0, sizeof(lum));
 126                 lum.handle = stream_datas[k].handle;
 127                 lum.cmd = LTTNG_UST_RELEASE;
 128                 ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 129                 if (ret) {
 130                         printf("Error closing stream\n");
 131                         return ret;
 132                 }
 133                 if (stream_datas[k].shm_fd >= 0) {
 134                         ret = close(stream_datas[k].shm_fd);
 135                         if (ret) {
 136                                 printf("Error closing stream shm_fd\n");
 137                                 return ret;
 138                         }
 139                 }
 140                 if (stream_datas[k].wait_fd >= 0) {
 141                         ret = close(stream_datas[k].wait_fd);
 142                         if (ret) {
 143                                 printf("Error closing stream wait_fd\n");
 144                                 return ret;
 145                         }
 146                 }
 147         }
 148         return 0;
 149 }
 150
 151 static
 152 struct lttng_ust_shm_handle *map_channel(struct lttng_ust_object_data *chan_data,
 153                 struct lttng_ust_object_data *stream_datas, int nr_check)
 154 {
 155         struct lttng_ust_shm_handle *handle;
 156         struct channel *chan;
 157         int k, ret;
 158
 159         /* map metadata channel */
 160         handle = channel_handle_create(chan_data->shm_fd,
 161                 chan_data->wait_fd,
 162                 chan_data->memory_map_size);
 163         if (!handle) {
 164                 printf("create handle error\n");
 165                 return NULL;
 166         }
 167         chan_data->shm_fd = -1;
 168         chan_data->wait_fd = -1;
 169         chan = shmp(handle, handle->chan);
 170
 171         for (k = 0; k < nr_check; k++) {
 172                 struct lttng_ust_object_data *stream_data = &stream_datas[k];
 173
 174                 if (!stream_data->handle)
 175                         break;
 176                 /* map stream */
 177                 ret = channel_handle_add_stream(handle,
 178                         stream_data->shm_fd,
 179                         stream_data->wait_fd,
 180                         stream_data->memory_map_size);
 181                 if (ret) {
 182                         printf("add stream error\n");
 183                         goto error_destroy;
 184                 }
 185                 stream_data->shm_fd = -1;
 186                 stream_data->wait_fd = -1;
 187         }
 188         return handle;
 189
 190 error_destroy:
 191         channel_destroy(chan, handle, 1);
 192         return NULL;
 193 }
 194
 195 static
 196 void unmap_channel(struct lttng_ust_shm_handle *handle)
 197 {
 198         struct channel *chan;
 199
 200         chan = shmp(handle, handle->chan);
 201         /* unmap channel */
 202         channel_destroy(chan, handle, 1);
 203 }
 204
 205 static
 206 int consume_stream(struct lttng_ust_shm_handle *handle, int cpu, char *outfile)
 207 {
 208         struct channel *chan;
 209         struct lttng_ust_lib_ring_buffer *buf;
 210         int outfd, ret;
 211         int *shm_fd, *wait_fd;
 212         uint64_t *memory_map_size;
 213
 214         chan = shmp(handle, handle->chan);
 215
 216         /* open stream */
 217         buf = channel_get_ring_buffer(&chan->backend.config,
 218                 chan, cpu, handle, &shm_fd, &wait_fd, &memory_map_size);
 219         if (!buf)
 220                 return -ENOENT;
 221         ret = lib_ring_buffer_open_read(buf, handle, 1);
 222         if (ret) {
 223                 return -1;
 224         }
 225
 226         /* copy */
 227         outfd = open(outfile, O_WRONLY | O_CREAT | O_TRUNC,
 228                         S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
 229         if (outfd < 0) {
 230                 perror("open output");
 231                 return -1;
 232         }
 233
 234         printf("Waiting for buffer data for %s\n", outfile);
 235         for (;;) {
 236                 unsigned long read_size;
 237                 unsigned long copy_size;
 238                 char *ptr;
 239
 240                 ret = lib_ring_buffer_get_next_subbuf(buf, handle);
 241                 printf("get next ret %d\n", ret);
 242                 if (ret == -ENODATA)
 243                         break;
 244                 if (ret == -EAGAIN) {
 245                         sleep(1);
 246                         continue;
 247                 }
 248                 if (ret) {
 249                         printf("Error %d in lib_ring_buffer_get_next_subbuf\n", ret);
 250                         return -1;
 251                 }
 252                 read_size = lib_ring_buffer_get_read_data_size(
 253                         &chan->backend.config, buf, handle);
 254                 read_size = PAGE_ALIGN(read_size);
 255                 ptr = lib_ring_buffer_read_offset_address(
 256                         &buf->backend, 0, handle);
 257                 printf("WRITE: copy %lu bytes\n", read_size);
 258                 copy_size = write(outfd, ptr, read_size);
 259                 if (copy_size < read_size) {
 260                         printf("write issue: copied %lu, expected %lu\n", copy_size, read_size);
 261                 }
 262                 lib_ring_buffer_put_next_subbuf(buf, handle);
 263         }
 264
 265         ret = close(outfd);
 266         if (ret) {
 267                 perror("close");
 268                 return -1;
 269         }
 270
 271         /* close stream */
 272         lib_ring_buffer_release_read(buf, handle, 1);
 273         return 0;
 274 }
 275
 276 static
 277 int consume_buffers(const char *outputpath)
 278 {
 279         int k, ret;
 280         mode_t old_umask;
 281         char pathname[PATH_MAX];
 282         struct lttng_ust_shm_handle *handle;
 283
 284         snprintf(pathname, PATH_MAX - 1, "%s", outputpath);
 285         old_umask = umask(0);
 286         ret = mkdir(pathname, S_IRWXU | S_IRWXG);
 287         if (ret && errno != EEXIST) {
 288                 perror("mkdir");
 289                 umask(old_umask);
 290                 return -1;
 291         }
 292         umask(old_umask);
 293
 294         /* copy metadata */
 295         handle = map_channel(&metadata_data,
 296                         &metadata_stream_data, 1);
 297         if (!handle)
 298                 return -1;
 299         snprintf(pathname, PATH_MAX - 1,
 300                 "%s/metadata", outputpath);
 301         ret = consume_stream(handle, -1, pathname);
 302         if (ret && ret != -ENOENT) {
 303                 printf("Error in consume_stream\n");
 304                 return ret;
 305         }
 306         unmap_channel(handle);
 307
 308         /* copy binary data */
 309         handle = map_channel(&channel_data,
 310                         stream_data, MAX_NR_STREAMS);
 311         if (!handle)
 312                 return -1;
 313         for (k = 0; k < MAX_NR_STREAMS; k++) {
 314                 snprintf(pathname, PATH_MAX - 1,
 315                         "%s/data_%u", outputpath, k);
 316                 ret = consume_stream(handle, k, pathname);
 317                 if (ret && ret != -ENOENT) {
 318                         printf("Error in consume_stream\n");
 319                         return ret;
 320                 }
 321         }
 322         unmap_channel(handle);
 323
 324         return 0;
 325 }
 326
 327 static
 328 int send_app_msgs(int sock, const char *outputpath,
 329                 unsigned int nr_events, const char **event_names)
 330 {
 331         struct ustcomm_ust_msg lum;
 332         struct ustcomm_ust_reply lur;
 333         int ret, k;
 334
 335         /* Create session */
 336         memset(&lum, 0, sizeof(lum));
 337         lum.handle = LTTNG_UST_ROOT_HANDLE;
 338         lum.cmd = LTTNG_UST_SESSION;
 339         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 340         if (ret)
 341                 return ret;
 342         session_handle = lur.ret_val;
 343         printf("received session handle %u\n", session_handle);
 344
 345         /* Create metadata channel */
 346         memset(&lum, 0, sizeof(lum));
 347         lum.handle = session_handle;
 348         lum.cmd = LTTNG_UST_METADATA;
 349         lum.u.channel.overwrite = 0;
 350         lum.u.channel.subbuf_size = 32768;
 351         lum.u.channel.num_subbuf = 4;
 352         lum.u.channel.switch_timer_interval = 0;
 353         lum.u.channel.read_timer_interval = 0;
 354         lum.u.channel.output = LTTNG_UST_MMAP;
 355         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 356         if (ret)
 357                 return ret;
 358         metadata_data.handle = lur.ret_val;
 359         printf("received metadata handle %u\n", metadata_data.handle);
 360         if (lur.ret_code == LTTNG_UST_OK) {
 361                 ssize_t len;
 362
 363                 metadata_data.memory_map_size = lur.u.channel.memory_map_size;
 364                 /* get shm fd */
 365                 len = ustcomm_recv_fd(sock);
 366                 if (len < 0)
 367                         return -EINVAL;
 368                 metadata_data.shm_fd = len;
 369                 /* get wait fd */
 370                 len = ustcomm_recv_fd(sock);
 371                 if (len < 0)
 372                         return -EINVAL;
 373                 metadata_data.wait_fd = len;
 374         }
 375
 376         ret = open_streams(sock, metadata_data.handle,
 377                         &metadata_stream_data, 1);
 378         if (ret) {
 379                 printf("Error in open_streams\n");
 380                 return ret;
 381         }
 382
 383         /* Create data channel */
 384         memset(&lum, 0, sizeof(lum));
 385         lum.handle = session_handle;
 386         lum.cmd = LTTNG_UST_CHANNEL;
 387         //lum.u.channel.overwrite = 0;
 388         lum.u.channel.overwrite = 1;
 389         lum.u.channel.subbuf_size = 32768;
 390         lum.u.channel.num_subbuf = 8;
 391         //lum.u.channel.num_subbuf = 4;
 392         //lum.u.channel.num_subbuf = 2;
 393         lum.u.channel.switch_timer_interval = 0;
 394         lum.u.channel.read_timer_interval = 0;
 395         lum.u.channel.output = LTTNG_UST_MMAP;
 396         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 397         if (ret)
 398                 return ret;
 399         channel_data.handle = lur.ret_val;
 400         printf("received channel handle %u\n", channel_data.handle);
 401         if (lur.ret_code == LTTNG_UST_OK) {
 402                 ssize_t len;
 403
 404                 channel_data.memory_map_size = lur.u.channel.memory_map_size;
 405                 /* get shm fd */
 406                 len = ustcomm_recv_fd(sock);
 407                 if (len < 0)
 408                         return -EINVAL;
 409                 channel_data.shm_fd = len;
 410                 /* get wait fd */
 411                 len = ustcomm_recv_fd(sock);
 412                 if (len < 0)
 413                         return -EINVAL;
 414                 channel_data.wait_fd = len;
 415         }
 416
 417         /* Create events */
 418         for (k = 0; k < nr_events; k++) {
 419                 memset(&lum, 0, sizeof(lum));
 420                 lum.handle = channel_data.handle;
 421                 lum.cmd = LTTNG_UST_EVENT;
 422                 strncpy(lum.u.event.name, event_names[k],
 423                         LTTNG_UST_SYM_NAME_LEN);
 424                 lum.u.event.instrumentation = LTTNG_UST_TRACEPOINT;
 425                 ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 426                 if (ret)
 427                         return ret;
 428                 event_handle[k] = lur.ret_val;
 429                 printf("received event handle %u\n", event_handle[k]);
 430         }
 431
 432         /* Attach vtid context */
 433         memset(&lum, 0, sizeof(lum));
 434         lum.handle = channel_data.handle;
 435         lum.cmd = LTTNG_UST_CONTEXT;
 436         lum.u.context.ctx = LTTNG_UST_CONTEXT_VTID;
 437         //lum.u.context.ctx = LTTNG_UST_CONTEXT_PTHREAD_ID;
 438         //lum.u.context.ctx = LTTNG_UST_CONTEXT_VPID;
 439         //lum.u.context.ctx = LTTNG_UST_CONTEXT_PROCNAME;
 440         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 441         if (ret)
 442                 return ret;
 443         context_handle = lur.ret_val;
 444         printf("received context handle %u\n", context_handle);
 445
 446         /* Get references to channel streams */
 447         ret = open_streams(sock, channel_data.handle,
 448                         stream_data, MAX_NR_STREAMS);
 449         if (ret) {
 450                 printf("Error in open_streams\n");
 451                 return ret;
 452         }
 453
 454         memset(&lum, 0, sizeof(lum));
 455         lum.handle = session_handle;
 456         lum.cmd = LTTNG_UST_SESSION_START;
 457         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 458         if (ret)
 459                 return ret;
 460         printf("Session handle %u started.\n", session_handle);
 461
 462         /* Tell application registration is done */
 463         memset(&lum, 0, sizeof(lum));
 464         lum.handle = LTTNG_UST_ROOT_HANDLE;
 465         lum.cmd = LTTNG_UST_REGISTER_DONE;
 466         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 467         if (ret)
 468                 return ret;
 469         printf("Registration done acknowledged.\n");
 470
 471         sleep(4);
 472
 473         ret = consume_buffers(outputpath);
 474         if (ret) {
 475                 printf("Error in consume_buffers\n");
 476                 return ret;
 477         }
 478
 479         /* Release data channel */
 480         /* Release streams */
 481         ret = close_streams(sock, stream_data,
 482                         MAX_NR_STREAMS);
 483         if (ret)
 484                 return ret;
 485
 486         /* Release context */
 487         memset(&lum, 0, sizeof(lum));
 488         lum.handle = context_handle;
 489         lum.cmd = LTTNG_UST_RELEASE;
 490         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 491         if (ret)
 492                 return ret;
 493
 494         /* Release events */
 495         for (k = 0; k < nr_events; k++) {
 496                 memset(&lum, 0, sizeof(lum));
 497                 lum.handle = event_handle[k];
 498                 lum.cmd = LTTNG_UST_RELEASE;
 499                 ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 500                 if (ret)
 501                         return ret;
 502         }
 503         memset(&lum, 0, sizeof(lum));
 504         lum.handle = channel_data.handle;
 505         lum.cmd = LTTNG_UST_RELEASE;
 506         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 507         if (ret)
 508                 return ret;
 509         if (channel_data.shm_fd >= 0) {
 510                 ret = close(channel_data.shm_fd);
 511                 if (ret)
 512                         return ret;
 513         }
 514         if (channel_data.wait_fd >= 0) {
 515                 ret = close(channel_data.wait_fd);
 516                 if (ret)
 517                         return ret;
 518         }
 519
 520         /* Release metadata channel */
 521         ret = close_streams(sock, &metadata_stream_data, 1);
 522         if (ret)
 523                 return ret;
 524
 525         memset(&lum, 0, sizeof(lum));
 526         lum.handle = metadata_data.handle;
 527         lum.cmd = LTTNG_UST_RELEASE;
 528         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 529         if (ret)
 530                 return ret;
 531         if (metadata_data.shm_fd >= 0) {
 532                 ret = close(metadata_data.shm_fd);
 533                 if (ret)
 534                         return ret;
 535         }
 536         if (metadata_data.wait_fd >= 0) {
 537                 ret = close(metadata_data.wait_fd);
 538                 if (ret)
 539                         return ret;
 540         }
 541
 542         /* Release session */
 543         memset(&lum, 0, sizeof(lum));
 544         lum.handle = session_handle;
 545         lum.cmd = LTTNG_UST_RELEASE;
 546         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 547         if (ret)
 548                 return ret;
 549
 550         return 0;
 551 }
 552
 553 /*
 554  * Using fork to set umask in the child process (not multi-thread safe). We
 555  * deal with the shm_open vs ftruncate race (happening when the sessiond owns
 556  * the shm and does not let everybody modify it, to ensure safety against
 557  * shm_unlink) by simply letting the mmap fail and retrying after a few
 558  * seconds. For global shm, everybody has rw access to it until the sessiond
 559  * starts.
 560  */
 561 static int get_wait_shm(char *shm_path, size_t mmap_size, int global)
 562 {
 563         int wait_shm_fd, ret;
 564         mode_t mode;
 565
 566         /* Default permissions */
 567         mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
 568
 569         /* Change owner of the shm path */
 570         if (global) {
 571                 ret = chown(shm_path, 0, 0);
 572                 if (ret < 0) {
 573                         if (errno != ENOENT) {
 574                                 perror("chown wait shm");
 575                                 goto error;
 576                         }
 577                 }
 578
 579                 /*
 580                  * If global session daemon, any application can register so the shm
 581                  * needs to be set in read-only mode for others.
 582                  */
 583                 mode |= S_IROTH;
 584         } else {
 585                 ret = chown(shm_path, getuid(), getgid());
 586                 if (ret < 0) {
 587                         if (errno != ENOENT) {
 588                                 perror("chown wait shm");
 589                                 goto error;
 590                         }
 591                 }
 592         }
 593
 594         /*
 595          * Set permissions to the shm even if we did not create the shm.
 596          */
 597         ret = chmod(shm_path, mode);
 598         if (ret < 0) {
 599                 if (errno != ENOENT) {
 600                         perror("chmod wait shm");
 601                         goto error;
 602                 }
 603         }
 604
 605         /*
 606          * We're alone in a child process, so we can modify the process-wide
 607          * umask.
 608          */
 609         umask(~mode);
 610
 611         /*
 612          * Try creating shm (or get rw access). We don't do an exclusive open,
 613          * because we allow other processes to create+ftruncate it concurrently.
 614          */
 615         wait_shm_fd = shm_open(shm_path, O_RDWR | O_CREAT, mode);
 616         if (wait_shm_fd < 0) {
 617                 perror("shm_open wait shm");
 618                 goto error;
 619         }
 620
 621         ret = ftruncate(wait_shm_fd, mmap_size);
 622         if (ret < 0) {
 623                 perror("ftruncate wait shm");
 624                 exit(EXIT_FAILURE);
 625         }
 626
 627         ret = fchmod(wait_shm_fd, mode);
 628         if (ret < 0) {
 629                 perror("fchmod");
 630                 exit(EXIT_FAILURE);
 631         }
 632
 633         printf("Got the wait shm fd %d\n", wait_shm_fd);
 634
 635         return wait_shm_fd;
 636
 637 error:
 638         printf("Failing to get the wait shm fd\n");
 639
 640         return -1;
 641 }
 642
 643 int update_futex(int fd, int active)
 644 {
 645         long page_size;
 646         char *wait_shm_mmap;
 647         int ret;
 648
 649         page_size = sysconf(_SC_PAGE_SIZE);
 650         if (page_size <= 0) {
 651                 if (!page_size) {
 652                         errno = EINVAL;
 653                 }
 654                 perror("Error in sysconf(_SC_PAGE_SIZE)");
 655                 goto error;
 656         }
 657         wait_shm_mmap = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
 658                   MAP_SHARED, fd, 0);
 659         if (wait_shm_mmap == MAP_FAILED) {
 660                 perror("mmap");
 661                 goto error;
 662         }
 663
 664         if (active) {
 665                 uatomic_set((int32_t *) wait_shm_mmap, 1);
 666                 if (futex_async((int32_t *) wait_shm_mmap, FUTEX_WAKE,
 667                                 INT_MAX, NULL, NULL, 0) < 0) {
 668                         perror("futex_async");
 669                         goto error;
 670                 }
 671         } else {
 672                 uatomic_set((int32_t *) wait_shm_mmap, 0);
 673         }
 674         ret = munmap(wait_shm_mmap, page_size);
 675         if (ret) {
 676                 perror("Error unmapping wait shm");
 677                 goto error;
 678         }
 679         return 0;
 680 error:
 681         return -1;
 682 }
 683
 684 /*
 685  * Set open files limit to unlimited. This daemon can open a large number of
 686  * file descriptors in order to consumer multiple kernel traces.
 687  */
 688 static void set_ulimit(void)
 689 {
 690         int ret;
 691         struct rlimit lim;
 692
 693         /*
 694          * If not root, we cannot increase our max open files. But our
 695          * scope is then limited to processes from a single user.
 696          */
 697         if (getuid() != 0)
 698                 return;
 699         /* The kernel does not allowed an infinite limit for open files */
 700         lim.rlim_cur = 65535;
 701         lim.rlim_max = 65535;
 702
 703         ret = setrlimit(RLIMIT_NOFILE, &lim);
 704         if (ret < 0) {
 705                 perror("failed to set open files limit");
 706         }
 707 }
 708
 709 /*
 710  * Usage:
 711  * ./ust-basic-tracing outputpath event_name1 event_name2 ....
 712  */
 713 int main(int argc, const char **argv)
 714 {
 715         const char *home_dir;
 716         char home_rundir[PATH_MAX];
 717         char *cmd = NULL;
 718         int ret, wait_shm_fd;
 719         struct sigaction act;
 720         mode_t old_umask = 0;
 721         const char *outputpath;
 722         const char **event_names;
 723         unsigned int nr_events;
 724         long page_size;
 725
 726         if (argc < 2) {
 727                 printf("Usage:\n");
 728                 printf("%s outputpath event_name1 event_name2 ...\n",
 729                         argv[0]);
 730                 exit(-1);
 731         }
 732         outputpath = argv[1];
 733         event_names = &argv[2];
 734         nr_events = argc - 2;
 735
 736         set_ulimit();
 737
 738         /* Ignore sigpipe */
 739         memset(&act, 0, sizeof(act));
 740         ret = sigemptyset(&act.sa_mask);
 741         if (ret == -1) {
 742                 perror("sigemptyset");
 743                 return -1;
 744         }
 745
 746         act.sa_handler = SIG_IGN;
 747         ret = sigaction(SIGPIPE, &act, NULL);
 748         if (ret == -1) {
 749                 perror("sigaction");
 750                 return -1;
 751         }
 752
 753         /* Handle SIGTERM */
 754         act.sa_handler = handle_signals;
 755         ret = sigaction(SIGTERM, &act, NULL);
 756         if (ret == -1) {
 757                 perror("sigaction");
 758                 return -1;
 759         }
 760         /* Handle SIGINT */
 761         ret = sigaction(SIGINT, &act, NULL);
 762         if (ret == -1) {
 763                 perror("sigaction");
 764                 return -1;
 765         }
 766
 767         page_size = sysconf(_SC_PAGE_SIZE);
 768         if (page_size <= 0) {
 769                 if (!page_size) {
 770                         errno = EINVAL;
 771                 }
 772                 perror("Error in sysconf(_SC_PAGE_SIZE)");
 773                 return -1;
 774         }
 775
 776         if (geteuid() == 0) {
 777                 ret = mkdir(LTTNG_RUNDIR, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
 778                 if (ret && errno != EEXIST) {
 779                         perror("mkdir");
 780                         return -1;
 781                 }
 782                 wait_shm_fd = get_wait_shm(DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH,
 783                                         page_size, 1);
 784                 if (wait_shm_fd < 0) {
 785                         perror("global wait shm error");
 786                         return -1;
 787                 }
 788                 strcpy(apps_sock_path, DEFAULT_GLOBAL_APPS_UNIX_SOCK);
 789                 old_umask = umask(0);
 790         } else {
 791                 home_dir = (const char *) getenv("HOME");
 792                 if (!home_dir) {
 793                         perror("getenv error");
 794                         return -ENOENT;
 795                 }
 796
 797                 snprintf(home_rundir, PATH_MAX,
 798                          LTTNG_HOME_RUNDIR, home_dir);
 799
 800                 ret = mkdir(home_rundir, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
 801                 if (ret && errno != EEXIST) {
 802                         perror("mkdir");
 803                         return -1;
 804                 }
 805
 806                 snprintf(local_apps_wait_shm_path, PATH_MAX,
 807                          DEFAULT_HOME_APPS_WAIT_SHM_PATH, getuid());
 808                 wait_shm_fd = get_wait_shm(local_apps_wait_shm_path,
 809                                         page_size, 0);
 810                 if (wait_shm_fd < 0) {
 811                         perror("local wait shm error");
 812                         return -1;
 813                 }
 814                 snprintf(apps_sock_path, PATH_MAX,
 815                          DEFAULT_HOME_APPS_UNIX_SOCK, home_dir);
 816         }
 817
 818         ret = ustcomm_create_unix_sock(apps_sock_path);
 819         if (ret < 0) {
 820                 perror("create error");
 821                 return ret;
 822         }
 823         apps_socket = ret;
 824
 825         if (getuid() == 0) {
 826                 /* File permission MUST be 666 */
 827                 ret = chmod(apps_sock_path,
 828                                 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
 829                 if (ret < 0) {
 830                         printf("Set file permissions failed: %s\n", apps_sock_path);
 831                         perror("chmod");
 832                         goto end;
 833                 }
 834                 umask(old_umask);
 835         }
 836         ret = ustcomm_listen_unix_sock(apps_socket);
 837         if (ret < 0) {
 838                 perror("listen error");
 839                 return ret;
 840         }
 841
 842         /* wake up futexes */
 843         ret = update_futex(wait_shm_fd, 1);
 844         if (ret) {
 845                 fprintf(stderr, "Error wakeup futex\n");
 846                 return -1;
 847         }
 848
 849         for (;;) {
 850                 int sock;
 851                 ssize_t len;
 852                 struct {
 853                         uint32_t major;
 854                         uint32_t minor;
 855                         pid_t pid;
 856                         pid_t ppid;
 857                         uid_t uid;
 858                         gid_t gid;
 859                         uint32_t bits_per_long;
 860                         char name[16];  /* Process name */
 861                 } reg_msg;
 862                 char bufname[17];
 863
 864                 if (quit_program)
 865                         break;
 866
 867                 printf("Accepting application registration\n");
 868                 sock = ustcomm_accept_unix_sock(apps_socket);
 869                 if (sock < 0) {
 870                         perror("accept error");
 871                         goto end;
 872                 }
 873
 874                 /*
 875                  * Basic recv here to handle the very simple data
 876                  * that the libust send to register (reg_msg).
 877                  */
 878                 len = ustcomm_recv_unix_sock(sock, &reg_msg, sizeof(reg_msg));
 879                 if (len < 0 || len != sizeof(reg_msg)) {
 880                         perror("ustcomm_recv_unix_sock");
 881                         continue;
 882                 }
 883                 memcpy(bufname, reg_msg.name, 16);
 884                 bufname[16] = '\0';
 885                 printf("Application %s pid %u ppid %u uid %u gid %u has registered (version : %u.%u)\n",
 886                         bufname, reg_msg.pid, reg_msg.ppid, reg_msg.uid,
 887                         reg_msg.gid, reg_msg.major, reg_msg.minor);
 888                 ret = send_app_msgs(sock, outputpath, nr_events, event_names);
 889                 if (ret) {
 890                         printf("Error in send_app_msgs.\n");
 891                         sleep(1);
 892                 }
 893                 close(sock);
 894         }
 895
 896 end:
 897         printf("quitting.\n");
 898         /* Let applications know we are not responding anymore */
 899         ret = update_futex(wait_shm_fd, 0);
 900         if (ret) {
 901                 fprintf(stderr, "Error wakeup futex\n");
 902                 return -1;
 903         }
 904
 905         if (geteuid()) {
 906                 printf("Removing %s directory\n", home_rundir);
 907                 ret = asprintf(&cmd, "rm -rf %s", home_rundir);
 908                 if (ret < 0) {
 909                         printf("asprintf failed. Something is really wrong!\n");
 910                         return -1;
 911                 }
 912
 913                 /* Remove lttng run directory */
 914                 ret = system(cmd);
 915                 if (ret < 0) {
 916                         printf("Unable to clean %s\n", home_rundir);
 917                         return -1;
 918                 }
 919         }
 920
 921
 922         return 0;
 923 }