lttng-sessiond/ust-consumer.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the Free
   6  * Software Foundation; only version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA  02111-1307, USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <errno.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #include <lttngerr.h>
  26 #include <lttng-share.h>
  27 #include <lttng-sessiond-comm.h>
  28 #include <lttng/lttng-consumer.h>
  29
  30 #include "hashtable.h"
  31 #include "ust-consumer.h"
  32
  33 /*
  34  * Send all stream fds of UST channel to the consumer.
  35  */
  36 static int send_channel_streams(int sock,
  37                 struct ust_app_channel *uchan)
  38 {
  39         int ret, fd;
  40         struct lttcomm_consumer_msg lum;
  41         struct ltt_ust_stream *stream, *tmp;
  42
  43         DBG("Sending streams of channel %s to UST consumer", uchan->name);
  44
  45         /* Send channel */
  46         lum.cmd_type = LTTNG_CONSUMER_ADD_CHANNEL;
  47
  48         /*
  49          * We need to keep shm_fd open while we transfer the stream file
  50          * descriptors to make sure this key stays unique within the
  51          * session daemon. We can free the channel shm_fd without
  52          * problem after we finished sending stream fds for that
  53          * channel.
  54          */
  55         lum.u.channel.channel_key = uchan->obj->shm_fd;
  56         lum.u.channel.max_sb_size = uchan->attr.subbuf_size;
  57         lum.u.channel.mmap_len = uchan->obj->memory_map_size;
  58         DBG("Sending channel %d to consumer", lum.u.channel.channel_key);
  59         ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
  60         if (ret < 0) {
  61                 perror("send consumer channel");
  62                 goto error;
  63         }
  64         fd = uchan->obj->shm_fd;
  65         ret = lttcomm_send_fds_unix_sock(sock, &fd, 1);
  66         if (ret < 0) {
  67                 perror("send consumer channel ancillary data");
  68                 goto error;
  69         }
  70
  71         cds_list_for_each_entry_safe(stream, tmp, &uchan->streams.head, list) {
  72                 int fds[2];
  73
  74                 if (!stream->obj->shm_fd) {
  75                         continue;
  76                 }
  77                 lum.cmd_type = LTTNG_CONSUMER_ADD_STREAM;
  78                 lum.u.stream.channel_key = uchan->obj->shm_fd;
  79                 lum.u.stream.stream_key = stream->obj->shm_fd;
  80                 lum.u.stream.state = LTTNG_CONSUMER_ACTIVE_STREAM;
  81                 /*
  82                  * FIXME Hack alert! we force MMAP for now. Mixup
  83                  * between EVENT and UST enums elsewhere.
  84                  */
  85                 lum.u.stream.output = DEFAULT_UST_CHANNEL_OUTPUT;
  86                 lum.u.stream.mmap_len = stream->obj->memory_map_size;
  87                 strncpy(lum.u.stream.path_name, stream->pathname, PATH_MAX - 1);
  88                 lum.u.stream.path_name[PATH_MAX - 1] = '\0';
  89                 DBG("Sending stream %d to consumer", lum.u.stream.stream_key);
  90                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
  91                 if (ret < 0) {
  92                         perror("send consumer stream");
  93                         goto error;
  94                 }
  95
  96                 fds[0] = stream->obj->shm_fd;
  97                 fds[1] = stream->obj->wait_fd;
  98                 ret = lttcomm_send_fds_unix_sock(sock, fds, 2);
  99                 if (ret < 0) {
 100                         perror("send consumer stream ancillary data");
 101                         goto error;
 102                 }
 103
 104                 /*
 105                  * We release the stream object here, as we have passed
 106                  * it to the consumer.
 107                  */
 108                 /* Ensure we don't let the app know (sock = -1). */
 109                 ustctl_release_object(-1, stream->obj);
 110                 cds_list_del(&stream->list);
 111                 free(stream);
 112         }
 113         /* Ensure we don't let the app know (sock = -1). */
 114         ustctl_release_object(-1, uchan->obj);
 115
 116         DBG("consumer channel streams sent");
 117
 118         return 0;
 119
 120 error:
 121         return ret;
 122 }
 123
 124 /*
 125  * Send all stream fds of the UST session to the consumer.
 126  */
 127 int ust_consumer_send_session(int consumer_fd, struct ust_app_session *usess)
 128 {
 129         int ret = 0;
 130         int sock = consumer_fd;
 131         struct cds_lfht_iter iter;
 132         struct cds_lfht_node *node;
 133         struct lttcomm_consumer_msg lum;
 134         struct ust_app_channel *uchan;
 135
 136         DBG("Sending metadata stream fd");
 137
 138         if (usess->metadata->obj->shm_fd != 0) {
 139                 int fd;
 140                 int fds[2];
 141
 142                 /* Send metadata channel fd */
 143                 lum.cmd_type = LTTNG_CONSUMER_ADD_CHANNEL;
 144                 lum.u.channel.channel_key = usess->metadata->obj->shm_fd;
 145                 lum.u.channel.max_sb_size = usess->metadata->attr.subbuf_size;
 146                 lum.u.channel.mmap_len = usess->metadata->obj->memory_map_size;
 147                 DBG("Sending metadata channel %d to consumer", lum.u.channel.channel_key);
 148                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
 149                 if (ret < 0) {
 150                         perror("send consumer channel");
 151                         goto error;
 152                 }
 153                 fd = usess->metadata->obj->shm_fd;
 154                 ret = lttcomm_send_fds_unix_sock(sock, &fd, 1);
 155                 if (ret < 0) {
 156                         perror("send consumer metadata channel");
 157                         goto error;
 158                 }
 159
 160                 /* Send metadata stream fd */
 161                 lum.cmd_type = LTTNG_CONSUMER_ADD_STREAM;
 162                 lum.u.stream.channel_key = usess->metadata->obj->shm_fd;
 163                 lum.u.stream.stream_key = usess->metadata->stream_obj->shm_fd;
 164                 lum.u.stream.state = LTTNG_CONSUMER_ACTIVE_STREAM;
 165                 lum.u.stream.output = DEFAULT_UST_CHANNEL_OUTPUT;
 166                 lum.u.stream.mmap_len = usess->metadata->stream_obj->memory_map_size;
 167                 strncpy(lum.u.stream.path_name, usess->metadata->pathname, PATH_MAX - 1);
 168                 lum.u.stream.path_name[PATH_MAX - 1] = '\0';
 169                 DBG("Sending metadata stream %d to consumer", lum.u.stream.stream_key);
 170                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
 171                 if (ret < 0) {
 172                         perror("send consumer metadata stream");
 173                         goto error;
 174                 }
 175                 fds[0] = usess->metadata->stream_obj->shm_fd;
 176                 fds[1] = usess->metadata->stream_obj->wait_fd;
 177                 ret = lttcomm_send_fds_unix_sock(sock, fds, 2);
 178                 if (ret < 0) {
 179                         perror("send consumer stream");
 180                         goto error;
 181                 }
 182                 /* Metadata fds passed to consumer, release them. */
 183                 /* Ensure we don't let the app know (sock = -1). */
 184                 ustctl_release_object(-1, usess->metadata->stream_obj);
 185                 ustctl_release_object(-1, usess->metadata->obj);
 186         }
 187
 188         /* Send each channel fd streams of session */
 189         rcu_read_lock();
 190         hashtable_get_first(usess->channels, &iter);
 191         while ((node = hashtable_iter_get_node(&iter)) != NULL) {
 192                 uchan = caa_container_of(node, struct ust_app_channel, node);
 193
 194                 ret = send_channel_streams(sock, uchan);
 195                 if (ret < 0) {
 196                         rcu_read_unlock();
 197                         goto error;
 198                 }
 199                 hashtable_get_next(usess->channels, &iter);
 200         }
 201         rcu_read_unlock();
 202
 203         DBG("consumer fds (metadata and channel streams) sent");
 204
 205         return 0;
 206
 207 error:
 208         return ret;
 209 }