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                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 212                                 msg.u.stream.stream_key,
 213                                 fds[0], fds[1],
 214                                 msg.u.stream.state,
 215                                 msg.u.stream.mmap_len,
 216                                 msg.u.stream.output,
 217                                 msg.u.stream.path_name);
 218                 if (new_stream == NULL) {
 219                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 220                         goto end;
 221                 }
 222                 if (ctx->on_recv_stream != NULL) {
 223                         ret = ctx->on_recv_stream(new_stream);
 224                         if (ret == 0) {
 225                                 consumer_add_stream(new_stream);
 226                         } else if (ret < 0) {
 227                                 goto end;
 228                         }
 229                 } else {
 230                         consumer_add_stream(new_stream);
 231                 }
 232                 break;
 233         }
 234         case LTTNG_CONSUMER_UPDATE_STREAM:
 235         {
 236                 if (ctx->on_update_stream != NULL) {
 237                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 238                         if (ret == 0) {
 239                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 240                         } else if (ret < 0) {
 241                                 goto end;
 242                         }
 243                 } else {
 244                         consumer_change_stream_state(msg.u.stream.stream_key,
 245                                 msg.u.stream.state);
 246                 }
 247                 break;
 248         }
 249         default:
 250                 break;
 251         }
 252 end:
 253         /* signal the poll thread */
 254         ret = write(ctx->consumer_poll_pipe[1], "4", 1);
 255         if (ret < 0) {
 256                 perror("write consumer poll");
 257         }
 258 end_nosignal:
 259         return 0;
 260 }
 261
 262 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 263 {
 264         struct lttng_ust_object_data obj;
 265
 266         obj.handle = -1;
 267         obj.shm_fd = chan->shm_fd;
 268         obj.wait_fd = chan->wait_fd;
 269         obj.memory_map_size = chan->mmap_len;
 270         chan->handle = ustctl_map_channel(&obj);
 271         if (!chan->handle) {
 272                 return -ENOMEM;
 273         }
 274         /*
 275          * The channel fds are passed to ustctl, we only keep a copy.
 276          */
 277         chan->shm_fd_is_copy = 1;
 278         chan->wait_fd_is_copy = 1;
 279
 280         return 0;
 281 }
 282
 283 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 284 {
 285         ustctl_unmap_channel(chan->handle);
 286 }
 287
 288 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 289 {
 290         struct lttng_ust_object_data obj;
 291         int ret;
 292
 293         obj.handle = -1;
 294         obj.shm_fd = stream->shm_fd;
 295         obj.wait_fd = stream->wait_fd;
 296         obj.memory_map_size = stream->mmap_len;
 297         ret = ustctl_add_stream(stream->chan->handle, &obj);
 298         if (ret)
 299                 return ret;
 300         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 301         if (!stream->buf)
 302                 return -EBUSY;
 303         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 304         if (!stream->mmap_base) {
 305                 return -EINVAL;
 306         }
 307         /*
 308          * The stream fds are passed to ustctl, we only keep a copy.
 309          */
 310         stream->shm_fd_is_copy = 1;
 311         stream->wait_fd_is_copy = 1;
 312
 313         return 0;
 314 }
 315
 316 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 317 {
 318         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 319 }