liblttng-ustconsumer/lttng-ustconsumer.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
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; only version 2
   8  * of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18  */
  19
  20 #define _GNU_SOURCE
  21 #include <assert.h>
  22 #include <fcntl.h>
  23 #include <poll.h>
  24 #include <pthread.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/mman.h>
  28 #include <sys/socket.h>
  29 #include <sys/types.h>
  30 #include <unistd.h>
  31
  32 #include <lttng-sessiond-comm.h>
  33 #include <lttng/lttng-ustconsumer.h>
  34 #include <lttng/ust-ctl.h>
  35 #include <lttngerr.h>
  36
  37 extern struct lttng_consumer_global_data consumer_data;
  38 extern int consumer_poll_timeout;
  39 extern volatile int consumer_quit;
  40
  41 /*
  42  * Mmap the ring buffer, read it and write the data to the tracefile.
  43  *
  44  * Returns the number of bytes written
  45  */
  46 int lttng_ustconsumer_on_read_subbuffer_mmap(
  47                 struct lttng_consumer_local_data *ctx,
  48                 struct lttng_consumer_stream *stream, unsigned long len)
  49 {
  50         unsigned long mmap_offset;
  51         long ret = 0;
  52         off_t orig_offset = stream->out_fd_offset;
  53         int outfd = stream->out_fd;
  54
  55         /* get the offset inside the fd to mmap */
  56         ret = ustctl_get_mmap_read_offset(stream->chan->handle,
  57                 stream->buf, &mmap_offset);
  58         if (ret != 0) {
  59                 ret = -errno;
  60                 perror("ustctl_get_mmap_read_offset");
  61                 goto end;
  62         }
  63         while (len > 0) {
  64                 ret = write(outfd, stream->mmap_base + mmap_offset, len);
  65                 if (ret >= len) {
  66                         len = 0;
  67                 } else if (ret < 0) {
  68                         ret = -errno;
  69                         perror("Error in file write");
  70                         goto end;
  71                 }
  72                 /* This won't block, but will start writeout asynchronously */
  73                 sync_file_range(outfd, stream->out_fd_offset, ret,
  74                                 SYNC_FILE_RANGE_WRITE);
  75                 stream->out_fd_offset += ret;
  76         }
  77
  78         lttng_consumer_sync_trace_file(stream, orig_offset);
  79
  80         goto end;
  81
  82 end:
  83         return ret;
  84 }
  85
  86 /*
  87  * Splice the data from the ring buffer to the tracefile.
  88  *
  89  * Returns the number of bytes spliced.
  90  */
  91 int lttng_ustconsumer_on_read_subbuffer_splice(
  92                 struct lttng_consumer_local_data *ctx,
  93                 struct lttng_consumer_stream *stream, unsigned long len)
  94 {
  95         return -ENOSYS;
  96 }
  97
  98 /*
  99  * Take a snapshot for a specific fd
 100  *
 101  * Returns 0 on success, < 0 on error
 102  */
 103 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 104                 struct lttng_consumer_stream *stream)
 105 {
 106         int ret = 0;
 107
 108         ret = ustctl_snapshot(stream->chan->handle, stream->buf);
 109         if (ret != 0) {
 110                 ret = errno;
 111                 perror("Getting sub-buffer snapshot.");
 112         }
 113
 114         return ret;
 115 }
 116
 117 /*
 118  * Get the produced position
 119  *
 120  * Returns 0 on success, < 0 on error
 121  */
 122 int lttng_ustconsumer_get_produced_snapshot(
 123                 struct lttng_consumer_local_data *ctx,
 124                 struct lttng_consumer_stream *stream,
 125                 unsigned long *pos)
 126 {
 127         int ret;
 128
 129         ret = ustctl_snapshot_get_produced(stream->chan->handle,
 130                         stream->buf, pos);
 131         if (ret != 0) {
 132                 ret = errno;
 133                 perror("kernctl_snapshot_get_produced");
 134         }
 135
 136         return ret;
 137 }
 138
 139 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 140                 int sock, struct pollfd *consumer_sockpoll)
 141 {
 142         ssize_t ret;
 143         struct lttcomm_consumer_msg msg;
 144
 145         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 146         if (ret != sizeof(msg)) {
 147                 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 148                 return ret;
 149         }
 150         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 151                 return -ENOENT;
 152         }
 153
 154         switch (msg.cmd_type) {
 155         case LTTNG_CONSUMER_ADD_CHANNEL:
 156         {
 157                 struct lttng_consumer_channel *new_channel;
 158                 int fds[1];
 159                 size_t nb_fd = 1;
 160
 161                 /* block */
 162                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 163                         return -EINTR;
 164                 }
 165                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 166                 if (ret != sizeof(fds)) {
 167                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 168                         return ret;
 169                 }
 170
 171                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 172
 173                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 174                                 fds[0], -1,
 175                                 msg.u.channel.mmap_len,
 176                                 msg.u.channel.max_sb_size);
 177                 if (new_channel == NULL) {
 178                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 179                         goto end_nosignal;
 180                 }
 181                 if (ctx->on_recv_channel != NULL) {
 182                         ret = ctx->on_recv_channel(new_channel);
 183                         if (ret == 0) {
 184                                 consumer_add_channel(new_channel);
 185                         } else if (ret < 0) {
 186                                 goto end_nosignal;
 187                         }
 188                 } else {
 189                         consumer_add_channel(new_channel);
 190                 }
 191                 goto end_nosignal;
 192         }
 193         case LTTNG_CONSUMER_ADD_STREAM:
 194         {
 195                 struct lttng_consumer_stream *new_stream;
 196                 int fds[2];
 197                 size_t nb_fd = 2;
 198
 199                 /* block */
 200                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 201                         return -EINTR;
 202                 }
 203                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 204                 if (ret != sizeof(fds)) {
 205                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 206                         return ret;
 207                 }
 208
 209                 DBG("consumer_add_stream %s (%d,%d)", msg.u.stream.path_name,
 210                         fds[0], fds[1]);
 211                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 212                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 213                                 msg.u.stream.stream_key,
 214                                 fds[0], fds[1],
 215                                 msg.u.stream.state,
 216                                 msg.u.stream.mmap_len,
 217                                 msg.u.stream.output,
 218                                 msg.u.stream.path_name);
 219                 if (new_stream == NULL) {
 220                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 221                         goto end;
 222                 }
 223                 if (ctx->on_recv_stream != NULL) {
 224                         ret = ctx->on_recv_stream(new_stream);
 225                         if (ret == 0) {
 226                                 consumer_add_stream(new_stream);
 227                         } else if (ret < 0) {
 228                                 goto end;
 229                         }
 230                 } else {
 231                         consumer_add_stream(new_stream);
 232                 }
 233                 break;
 234         }
 235         case LTTNG_CONSUMER_UPDATE_STREAM:
 236         {
 237                 if (ctx->on_update_stream != NULL) {
 238                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 239                         if (ret == 0) {
 240                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 241                         } else if (ret < 0) {
 242                                 goto end;
 243                         }
 244                 } else {
 245                         consumer_change_stream_state(msg.u.stream.stream_key,
 246                                 msg.u.stream.state);
 247                 }
 248                 break;
 249         }
 250         default:
 251                 break;
 252         }
 253 end:
 254         /* signal the poll thread */
 255         ret = write(ctx->consumer_poll_pipe[1], "4", 1);
 256         if (ret < 0) {
 257                 perror("write consumer poll");
 258         }
 259 end_nosignal:
 260         return 0;
 261 }
 262
 263 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 264 {
 265         struct lttng_ust_object_data obj;
 266
 267         obj.handle = -1;
 268         obj.shm_fd = chan->shm_fd;
 269         obj.wait_fd = chan->wait_fd;
 270         obj.memory_map_size = chan->mmap_len;
 271         chan->handle = ustctl_map_channel(&obj);
 272         if (!chan->handle) {
 273                 return -ENOMEM;
 274         }
 275         /*
 276          * The channel fds are passed to ustctl, we only keep a copy.
 277          */
 278         chan->shm_fd_is_copy = 1;
 279         chan->wait_fd_is_copy = 1;
 280
 281         return 0;
 282 }
 283
 284 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 285 {
 286         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 287 }
 288
 289 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 290 {
 291         ustctl_unmap_channel(chan->handle);
 292 }
 293
 294 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 295 {
 296         struct lttng_ust_object_data obj;
 297         int ret;
 298
 299         obj.handle = -1;
 300         obj.shm_fd = stream->shm_fd;
 301         obj.wait_fd = stream->wait_fd;
 302         obj.memory_map_size = stream->mmap_len;
 303         ret = ustctl_add_stream(stream->chan->handle, &obj);
 304         if (ret)
 305                 return ret;
 306         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 307         if (!stream->buf)
 308                 return -EBUSY;
 309         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 310         if (!stream->mmap_base) {
 311                 return -EINVAL;
 312         }
 313         /*
 314          * The stream fds are passed to ustctl, we only keep a copy.
 315          */
 316         stream->shm_fd_is_copy = 1;
 317         stream->wait_fd_is_copy = 1;
 318
 319         return 0;
 320 }
 321
 322 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 323 {
 324         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 325 }
 326
 327
 328 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 329                 struct lttng_consumer_local_data *ctx)
 330 {
 331         unsigned long len;
 332         int err;
 333         long ret = 0;
 334         struct lttng_ust_shm_handle *handle;
 335         struct lttng_ust_lib_ring_buffer *buf;
 336         char dummy;
 337         ssize_t readlen;
 338
 339         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 340                 stream->wait_fd, stream->key);
 341
 342         /* We can consume the 1 byte written into the wait_fd by UST */
 343         do {
 344                 readlen = read(stream->wait_fd, &dummy, 1);
 345         } while (readlen == -1 && errno == -EINTR);
 346         if (readlen == -1) {
 347                 ret = readlen;
 348                 goto end;
 349         }
 350
 351         buf = stream->buf;
 352         handle = stream->chan->handle;
 353         /* Get the next subbuffer */
 354         err = ustctl_get_next_subbuf(handle, buf);
 355         if (err != 0) {
 356                 ret = errno;
 357                 /*
 358                  * This is a debug message even for single-threaded consumer,
 359                  * because poll() have more relaxed criterions than get subbuf,
 360                  * so get_subbuf may fail for short race windows where poll()
 361                  * would issue wakeups.
 362                  */
 363                 DBG("Reserving sub buffer failed (everything is normal, "
 364                                 "it is due to concurrency)");
 365                 goto end;
 366         }
 367         assert(stream->output == LTTNG_EVENT_MMAP);
 368         /* read the used subbuffer size */
 369         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 370         if (err != 0) {
 371                 ret = errno;
 372                 perror("Getting sub-buffer len failed.");
 373                 goto end;
 374         }
 375         /* write the subbuffer to the tracefile */
 376         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 377         if (ret < 0) {
 378                 /*
 379                  * display the error but continue processing to try
 380                  * to release the subbuffer
 381                  */
 382                 ERR("Error writing to tracefile");
 383         }
 384         err = ustctl_put_next_subbuf(handle, buf);
 385         if (err != 0) {
 386                 ret = errno;
 387                 if (errno == EFAULT) {
 388                         perror("Error in unreserving sub buffer\n");
 389                 } else if (errno == EIO) {
 390                         /* Should never happen with newer LTTng versions */
 391                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 392                 }
 393                 goto end;
 394         }
 395 end:
 396         return ret;
 397 }
 398
 399 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 400 {
 401         int ret;
 402
 403         /* Opening the tracefile in write mode */
 404         if (stream->path_name != NULL) {
 405                 ret = open(stream->path_name,
 406                                 O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
 407                 if (ret < 0) {
 408                         ERR("Opening %s", stream->path_name);
 409                         perror("open");
 410                         goto error;
 411                 }
 412                 stream->out_fd = ret;
 413         }
 414
 415         /* we return 0 to let the library handle the FD internally */
 416         return 0;
 417
 418 error:
 419         return ret;
 420 }