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                         fprintf(stderr, "AAAAA\n");
 179                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 180                         goto end_nosignal;
 181                 }
 182                 if (ctx->on_recv_channel != NULL) {
 183                         ret = ctx->on_recv_channel(new_channel);
 184                         if (ret == 0) {
 185                                 consumer_add_channel(new_channel);
 186                         } else if (ret < 0) {
 187                                 goto end_nosignal;
 188                         }
 189                 } else {
 190                         consumer_add_channel(new_channel);
 191                 }
 192                 goto end_nosignal;
 193         }
 194         case LTTNG_CONSUMER_ADD_STREAM:
 195         {
 196                 struct lttng_consumer_stream *new_stream;
 197                 int fds[2];
 198                 size_t nb_fd = 2;
 199
 200                 /* block */
 201                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 202                         return -EINTR;
 203                 }
 204                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 205                 if (ret != sizeof(fds)) {
 206                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 207                         return ret;
 208                 }
 209
 210                 DBG("consumer_add_stream %s (%d,%d)", msg.u.stream.path_name,
 211                         fds[0], fds[1]);
 212                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 213                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 214                                 msg.u.stream.stream_key,
 215                                 fds[0], fds[1],
 216                                 msg.u.stream.state,
 217                                 msg.u.stream.mmap_len,
 218                                 msg.u.stream.output,
 219                                 msg.u.stream.path_name);
 220                 if (new_stream == NULL) {
 221                         fprintf(stderr, "BBBBBB\n");
 222                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 223                         goto end;
 224                 }
 225                 if (ctx->on_recv_stream != NULL) {
 226                         ret = ctx->on_recv_stream(new_stream);
 227                         if (ret == 0) {
 228                                 consumer_add_stream(new_stream);
 229                         } else if (ret < 0) {
 230                                 goto end;
 231                         }
 232                 } else {
 233                         consumer_add_stream(new_stream);
 234                 }
 235                 break;
 236         }
 237         case LTTNG_CONSUMER_UPDATE_STREAM:
 238         {
 239                 if (ctx->on_update_stream != NULL) {
 240                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 241                         if (ret == 0) {
 242                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 243                         } else if (ret < 0) {
 244                                 goto end;
 245                         }
 246                 } else {
 247                         consumer_change_stream_state(msg.u.stream.stream_key,
 248                                 msg.u.stream.state);
 249                 }
 250                 break;
 251         }
 252         default:
 253                 break;
 254         }
 255 end:
 256         /* signal the poll thread */
 257         ret = write(ctx->consumer_poll_pipe[1], "4", 1);
 258         if (ret < 0) {
 259                 perror("write consumer poll");
 260         }
 261 end_nosignal:
 262         return 0;
 263 }
 264
 265 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 266 {
 267         struct lttng_ust_object_data obj;
 268
 269         obj.handle = -1;
 270         obj.shm_fd = chan->shm_fd;
 271         obj.wait_fd = chan->wait_fd;
 272         obj.memory_map_size = chan->mmap_len;
 273         chan->handle = ustctl_map_channel(&obj);
 274         if (!chan->handle) {
 275                 return -ENOMEM;
 276         }
 277         /*
 278          * The channel fds are passed to ustctl, we only keep a copy.
 279          */
 280         chan->shm_fd_is_copy = 1;
 281         chan->wait_fd_is_copy = 1;
 282
 283         return 0;
 284 }
 285
 286 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 287 {
 288         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 289 }
 290
 291 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 292 {
 293         ustctl_unmap_channel(chan->handle);
 294 }
 295
 296 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 297 {
 298         struct lttng_ust_object_data obj;
 299         int ret;
 300
 301         obj.handle = -1;
 302         obj.shm_fd = stream->shm_fd;
 303         obj.wait_fd = stream->wait_fd;
 304         obj.memory_map_size = stream->mmap_len;
 305         ret = ustctl_add_stream(stream->chan->handle, &obj);
 306         if (ret)
 307                 return ret;
 308         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 309         if (!stream->buf)
 310                 return -EBUSY;
 311         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 312         if (!stream->mmap_base) {
 313                 return -EINVAL;
 314         }
 315         /*
 316          * The stream fds are passed to ustctl, we only keep a copy.
 317          */
 318         stream->shm_fd_is_copy = 1;
 319         stream->wait_fd_is_copy = 1;
 320
 321         return 0;
 322 }
 323
 324 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 325 {
 326         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 327 }
 328
 329
 330 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 331                 struct lttng_consumer_local_data *ctx)
 332 {
 333         unsigned long len;
 334         int err;
 335         long ret = 0;
 336         struct lttng_ust_shm_handle *handle;
 337         struct lttng_ust_lib_ring_buffer *buf;
 338         char dummy;
 339         ssize_t readlen;
 340
 341         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 342                 stream->wait_fd, stream->key);
 343
 344         /* We can consume the 1 byte written into the wait_fd by UST */
 345         do {
 346                 readlen = read(stream->wait_fd, &dummy, 1);
 347         } while (readlen == -1 && errno == -EINTR);
 348         if (readlen == -1) {
 349                 ret = readlen;
 350                 goto end;
 351         }
 352
 353         buf = stream->buf;
 354         handle = stream->chan->handle;
 355         /* Get the next subbuffer */
 356         err = ustctl_get_next_subbuf(handle, buf);
 357         if (err != 0) {
 358                 ret = errno;
 359                 /*
 360                  * This is a debug message even for single-threaded consumer,
 361                  * because poll() have more relaxed criterions than get subbuf,
 362                  * so get_subbuf may fail for short race windows where poll()
 363                  * would issue wakeups.
 364                  */
 365                 DBG("Reserving sub buffer failed (everything is normal, "
 366                                 "it is due to concurrency)");
 367                 goto end;
 368         }
 369         assert(stream->output == LTTNG_EVENT_MMAP);
 370         /* read the used subbuffer size */
 371         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 372         if (err != 0) {
 373                 ret = errno;
 374                 perror("Getting sub-buffer len failed.");
 375                 goto end;
 376         }
 377         /* write the subbuffer to the tracefile */
 378         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 379         if (ret < 0) {
 380                 /*
 381                  * display the error but continue processing to try
 382                  * to release the subbuffer
 383                  */
 384                 ERR("Error writing to tracefile");
 385         }
 386         err = ustctl_put_next_subbuf(handle, buf);
 387         if (err != 0) {
 388                 ret = errno;
 389                 if (errno == EFAULT) {
 390                         perror("Error in unreserving sub buffer\n");
 391                 } else if (errno == EIO) {
 392                         /* Should never happen with newer LTTng versions */
 393                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 394                 }
 395                 goto end;
 396         }
 397 end:
 398         return ret;
 399 }
 400
 401 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 402 {
 403         int ret;
 404
 405         /* Opening the tracefile in write mode */
 406         if (stream->path_name != NULL) {
 407                 ret = open(stream->path_name,
 408                                 O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
 409                 if (ret < 0) {
 410                         ERR("Opening %s", stream->path_name);
 411                         perror("open");
 412                         goto error;
 413                 }
 414                 stream->out_fd = ret;
 415         }
 416
 417         /* we return 0 to let the library handle the FD internally */
 418         return 0;
 419
 420 error:
 421         return ret;
 422 }