src/common/ust-consumer/ust-consumer.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <assert.h>
  21 #include <lttng/ust-ctl.h>
  22 #include <poll.h>
  23 #include <pthread.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/mman.h>
  27 #include <sys/socket.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <inttypes.h>
  31 #include <unistd.h>
  32
  33 #include <common/common.h>
  34 #include <common/sessiond-comm/sessiond-comm.h>
  35 #include <common/relayd/relayd.h>
  36 #include <common/compat/fcntl.h>
  37
  38 #include "ust-consumer.h"
  39
  40 extern struct lttng_consumer_global_data consumer_data;
  41 extern int consumer_poll_timeout;
  42 extern volatile int consumer_quit;
  43
  44 /*
  45  * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
  46  * compiled out, we isolate it in this library.
  47  */
  48 int lttng_ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
  49                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
  50 {
  51         return ustctl_get_mmap_read_offset(handle, buf, off);
  52 };
  53
  54 /*
  55  * Take a snapshot for a specific fd
  56  *
  57  * Returns 0 on success, < 0 on error
  58  */
  59 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
  60                 struct lttng_consumer_stream *stream)
  61 {
  62         int ret = 0;
  63
  64         ret = ustctl_snapshot(stream->chan->handle, stream->buf);
  65         if (ret != 0) {
  66                 errno = -ret;
  67                 PERROR("Getting sub-buffer snapshot.");
  68         }
  69
  70         return ret;
  71 }
  72
  73 /*
  74  * Get the produced position
  75  *
  76  * Returns 0 on success, < 0 on error
  77  */
  78 int lttng_ustconsumer_get_produced_snapshot(
  79                 struct lttng_consumer_local_data *ctx,
  80                 struct lttng_consumer_stream *stream,
  81                 unsigned long *pos)
  82 {
  83         int ret;
  84
  85         ret = ustctl_snapshot_get_produced(stream->chan->handle,
  86                         stream->buf, pos);
  87         if (ret != 0) {
  88                 errno = -ret;
  89                 PERROR("kernctl_snapshot_get_produced");
  90         }
  91
  92         return ret;
  93 }
  94
  95 /*
  96  * Receive command from session daemon and process it.
  97  *
  98  * Return 1 on success else a negative value or 0.
  99  */
 100 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 101                 int sock, struct pollfd *consumer_sockpoll)
 102 {
 103         ssize_t ret;
 104         struct lttcomm_consumer_msg msg;
 105
 106         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 107         if (ret != sizeof(msg)) {
 108                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 109                         ret, sizeof(msg));
 110                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 111                 return ret;
 112         }
 113         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 114                 return -ENOENT;
 115         }
 116
 117         /* relayd needs RCU read-side lock */
 118         rcu_read_lock();
 119
 120         switch (msg.cmd_type) {
 121         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 122         {
 123                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 124                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 125                                 &msg.u.relayd_sock.sock);
 126                 goto end_nosignal;
 127         }
 128         case LTTNG_CONSUMER_ADD_CHANNEL:
 129         {
 130                 struct lttng_consumer_channel *new_channel;
 131                 int fds[1];
 132                 size_t nb_fd = 1;
 133
 134                 DBG("UST Consumer adding channel");
 135
 136                 /* block */
 137                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 138                         rcu_read_unlock();
 139                         return -EINTR;
 140                 }
 141                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 142                 if (ret != sizeof(fds)) {
 143                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 144                         rcu_read_unlock();
 145                         return ret;
 146                 }
 147
 148                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 149
 150                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 151                                 fds[0], -1,
 152                                 msg.u.channel.mmap_len,
 153                                 msg.u.channel.max_sb_size);
 154                 if (new_channel == NULL) {
 155                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 156                         goto end_nosignal;
 157                 }
 158                 if (ctx->on_recv_channel != NULL) {
 159                         ret = ctx->on_recv_channel(new_channel);
 160                         if (ret == 0) {
 161                                 consumer_add_channel(new_channel);
 162                         } else if (ret < 0) {
 163                                 goto end_nosignal;
 164                         }
 165                 } else {
 166                         consumer_add_channel(new_channel);
 167                 }
 168                 goto end_nosignal;
 169         }
 170         case LTTNG_CONSUMER_ADD_STREAM:
 171         {
 172                 struct lttng_consumer_stream *new_stream;
 173                 int fds[2];
 174                 size_t nb_fd = 2;
 175                 struct consumer_relayd_sock_pair *relayd = NULL;
 176
 177                 DBG("UST Consumer adding stream");
 178
 179                 /* block */
 180                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 181                         rcu_read_unlock();
 182                         return -EINTR;
 183                 }
 184                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 185                 if (ret != sizeof(fds)) {
 186                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 187                         rcu_read_unlock();
 188                         return ret;
 189                 }
 190
 191                 DBG("consumer_add_stream chan %d stream %d",
 192                                 msg.u.stream.channel_key,
 193                                 msg.u.stream.stream_key);
 194
 195                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 196                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 197                                 msg.u.stream.stream_key,
 198                                 fds[0], fds[1],
 199                                 msg.u.stream.state,
 200                                 msg.u.stream.mmap_len,
 201                                 msg.u.stream.output,
 202                                 msg.u.stream.path_name,
 203                                 msg.u.stream.uid,
 204                                 msg.u.stream.gid,
 205                                 msg.u.stream.net_index,
 206                                 msg.u.stream.metadata_flag);
 207                 if (new_stream == NULL) {
 208                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 209                         goto end_nosignal;
 210                 }
 211
 212                 /* The stream is not metadata. Get relayd reference if exists. */
 213                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 214                 if (relayd != NULL) {
 215                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 216                         /* Add stream on the relayd */
 217                         ret = relayd_add_stream(&relayd->control_sock,
 218                                         msg.u.stream.name, msg.u.stream.path_name,
 219                                         &new_stream->relayd_stream_id);
 220                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 221                         if (ret < 0) {
 222                                 goto end_nosignal;
 223                         }
 224                 } else if (msg.u.stream.net_index != -1) {
 225                         ERR("Network sequence index %d unknown. Not adding stream.",
 226                                         msg.u.stream.net_index);
 227                         free(new_stream);
 228                         goto end_nosignal;
 229                 }
 230
 231                 if (ctx->on_recv_stream != NULL) {
 232                         ret = ctx->on_recv_stream(new_stream);
 233                         if (ret == 0) {
 234                                 consumer_add_stream(new_stream);
 235                         } else if (ret < 0) {
 236                                 goto end_nosignal;
 237                         }
 238                 } else {
 239                         consumer_add_stream(new_stream);
 240                 }
 241
 242                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
 243                                 msg.u.stream.path_name, fds[0], fds[1],
 244                                 new_stream->relayd_stream_id);
 245                 break;
 246         }
 247         case LTTNG_CONSUMER_DESTROY_RELAYD:
 248         {
 249                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 250                 struct consumer_relayd_sock_pair *relayd;
 251
 252                 DBG("UST consumer destroying relayd %" PRIu64, index);
 253
 254                 /* Get relayd reference if exists. */
 255                 relayd = consumer_find_relayd(index);
 256                 if (relayd == NULL) {
 257                         ERR("Unable to find relayd %" PRIu64, index);
 258                         goto end_nosignal;
 259                 }
 260
 261                 /*
 262                  * Each relayd socket pair has a refcount of stream attached to it
 263                  * which tells if the relayd is still active or not depending on the
 264                  * refcount value.
 265                  *
 266                  * This will set the destroy flag of the relayd object and destroy it
 267                  * if the refcount reaches zero when called.
 268                  *
 269                  * The destroy can happen either here or when a stream fd hangs up.
 270                  */
 271                 consumer_flag_relayd_for_destroy(relayd);
 272
 273                 goto end_nosignal;
 274         }
 275         case LTTNG_CONSUMER_UPDATE_STREAM:
 276         {
 277                 rcu_read_unlock();
 278                 return -ENOSYS;
 279 #if 0
 280                 if (ctx->on_update_stream != NULL) {
 281                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 282                         if (ret == 0) {
 283                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 284                         } else if (ret < 0) {
 285                                 goto end;
 286                         }
 287                 } else {
 288                         consumer_change_stream_state(msg.u.stream.stream_key,
 289                                 msg.u.stream.state);
 290                 }
 291                 break;
 292 #endif
 293         }
 294         default:
 295                 break;
 296         }
 297
 298         /*
 299          * Wake-up the other end by writing a null byte in the pipe (non-blocking).
 300          * Important note: Because writing into the pipe is non-blocking (and
 301          * therefore we allow dropping wakeup data, as long as there is wakeup data
 302          * present in the pipe buffer to wake up the other end), the other end
 303          * should perform the following sequence for waiting:
 304          *
 305          * 1) empty the pipe (reads).
 306          * 2) perform update operation.
 307          * 3) wait on the pipe (poll).
 308          */
 309         do {
 310                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 311         } while (ret < 0 && errno == EINTR);
 312 end_nosignal:
 313         rcu_read_unlock();
 314
 315         /*
 316          * Return 1 to indicate success since the 0 value can be a socket
 317          * shutdown during the recv() or send() call.
 318          */
 319         return 1;
 320 }
 321
 322 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 323 {
 324         struct lttng_ust_object_data obj;
 325
 326         obj.handle = -1;
 327         obj.shm_fd = chan->shm_fd;
 328         obj.wait_fd = chan->wait_fd;
 329         obj.memory_map_size = chan->mmap_len;
 330         chan->handle = ustctl_map_channel(&obj);
 331         if (!chan->handle) {
 332                 return -ENOMEM;
 333         }
 334         chan->wait_fd_is_copy = 1;
 335         chan->shm_fd = -1;
 336
 337         return 0;
 338 }
 339
 340 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 341 {
 342         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 343         stream->hangup_flush_done = 1;
 344 }
 345
 346 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 347 {
 348         ustctl_unmap_channel(chan->handle);
 349 }
 350
 351 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 352 {
 353         struct lttng_ust_object_data obj;
 354         int ret;
 355
 356         obj.handle = -1;
 357         obj.shm_fd = stream->shm_fd;
 358         obj.wait_fd = stream->wait_fd;
 359         obj.memory_map_size = stream->mmap_len;
 360         ret = ustctl_add_stream(stream->chan->handle, &obj);
 361         if (ret)
 362                 return ret;
 363         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 364         if (!stream->buf)
 365                 return -EBUSY;
 366         /* ustctl_open_stream_read has closed the shm fd. */
 367         stream->wait_fd_is_copy = 1;
 368         stream->shm_fd = -1;
 369
 370         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 371         if (!stream->mmap_base) {
 372                 return -EINVAL;
 373         }
 374
 375         return 0;
 376 }
 377
 378 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 379 {
 380         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 381 }
 382
 383
 384 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 385                 struct lttng_consumer_local_data *ctx)
 386 {
 387         unsigned long len;
 388         int err;
 389         long ret = 0;
 390         struct lttng_ust_shm_handle *handle;
 391         struct lttng_ust_lib_ring_buffer *buf;
 392         char dummy;
 393         ssize_t readlen;
 394
 395         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 396                 stream->wait_fd, stream->key);
 397
 398         /* We can consume the 1 byte written into the wait_fd by UST */
 399         if (!stream->hangup_flush_done) {
 400                 do {
 401                         readlen = read(stream->wait_fd, &dummy, 1);
 402                 } while (readlen == -1 && errno == EINTR);
 403                 if (readlen == -1) {
 404                         ret = readlen;
 405                         goto end;
 406                 }
 407         }
 408
 409         buf = stream->buf;
 410         handle = stream->chan->handle;
 411         /* Get the next subbuffer */
 412         err = ustctl_get_next_subbuf(handle, buf);
 413         if (err != 0) {
 414                 ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 415                 /*
 416                  * This is a debug message even for single-threaded consumer,
 417                  * because poll() have more relaxed criterions than get subbuf,
 418                  * so get_subbuf may fail for short race windows where poll()
 419                  * would issue wakeups.
 420                  */
 421                 DBG("Reserving sub buffer failed (everything is normal, "
 422                                 "it is due to concurrency)");
 423                 goto end;
 424         }
 425         assert(stream->output == LTTNG_EVENT_MMAP);
 426         /* read the used subbuffer size */
 427         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 428         assert(err == 0);
 429         /* write the subbuffer to the tracefile */
 430         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 431         if (ret != len) {
 432                 /*
 433                  * display the error but continue processing to try
 434                  * to release the subbuffer
 435                  */
 436                 ERR("Error writing to tracefile (expected: %ld, got: %ld)", ret, len);
 437         }
 438         err = ustctl_put_next_subbuf(handle, buf);
 439         assert(err == 0);
 440 end:
 441         return ret;
 442 }
 443
 444 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 445 {
 446         int ret;
 447
 448         /* Opening the tracefile in write mode */
 449         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 450                 ret = run_as_open(stream->path_name,
 451                                 O_WRONLY|O_CREAT|O_TRUNC,
 452                                 S_IRWXU|S_IRWXG|S_IRWXO,
 453                                 stream->uid, stream->gid);
 454                 if (ret < 0) {
 455                         ERR("Opening %s", stream->path_name);
 456                         PERROR("open");
 457                         goto error;
 458                 }
 459                 stream->out_fd = ret;
 460         }
 461
 462         /* we return 0 to let the library handle the FD internally */
 463         return 0;
 464
 465 error:
 466         return ret;
 467 }