src/bin/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 <common/common.h>
  26 #include <common/consumer.h>
  27 #include <common/defaults.h>
  28 #include <common/sessiond-comm/sessiond-comm.h>
  29
  30 #include "ust-consumer.h"
  31
  32 /*
  33  * Send all stream fds of UST channel to the consumer.
  34  */
  35 static int send_channel_streams(int sock,
  36                 struct ust_app_channel *uchan,
  37                 uid_t uid, gid_t gid)
  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                 lum.u.stream.uid = uid;
  88                 lum.u.stream.gid = gid;
  89                 strncpy(lum.u.stream.path_name, stream->pathname, PATH_MAX - 1);
  90                 lum.u.stream.path_name[PATH_MAX - 1] = '\0';
  91                 DBG("Sending stream %d to consumer", lum.u.stream.stream_key);
  92                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
  93                 if (ret < 0) {
  94                         PERROR("send consumer stream");
  95                         goto error;
  96                 }
  97
  98                 fds[0] = stream->obj->shm_fd;
  99                 fds[1] = stream->obj->wait_fd;
 100                 ret = lttcomm_send_fds_unix_sock(sock, fds, 2);
 101                 if (ret < 0) {
 102                         PERROR("send consumer stream ancillary data");
 103                         goto error;
 104                 }
 105         }
 106
 107         DBG("consumer channel streams sent");
 108
 109         return 0;
 110
 111 error:
 112         return ret;
 113 }
 114
 115 /*
 116  * Send all stream fds of the UST session to the consumer.
 117  */
 118 int ust_consumer_send_session(int consumer_fd, struct ust_app_session *usess)
 119 {
 120         int ret = 0;
 121         int sock = consumer_fd;
 122         struct lttng_ht_iter iter;
 123         struct lttcomm_consumer_msg lum;
 124         struct ust_app_channel *ua_chan;
 125
 126         DBG("Sending metadata stream fd");
 127
 128         if (consumer_fd < 0) {
 129                 ERR("Consumer has negative file descriptor");
 130                 return -EINVAL;
 131         }
 132
 133         if (usess->metadata->obj->shm_fd != 0) {
 134                 int fd;
 135                 int fds[2];
 136
 137                 /* Send metadata channel fd */
 138                 lum.cmd_type = LTTNG_CONSUMER_ADD_CHANNEL;
 139                 lum.u.channel.channel_key = usess->metadata->obj->shm_fd;
 140                 lum.u.channel.max_sb_size = usess->metadata->attr.subbuf_size;
 141                 lum.u.channel.mmap_len = usess->metadata->obj->memory_map_size;
 142                 DBG("Sending metadata channel %d to consumer", lum.u.channel.channel_key);
 143                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
 144                 if (ret < 0) {
 145                         PERROR("send consumer channel");
 146                         goto error;
 147                 }
 148                 fd = usess->metadata->obj->shm_fd;
 149                 ret = lttcomm_send_fds_unix_sock(sock, &fd, 1);
 150                 if (ret < 0) {
 151                         PERROR("send consumer metadata channel");
 152                         goto error;
 153                 }
 154
 155                 /* Send metadata stream fd */
 156                 lum.cmd_type = LTTNG_CONSUMER_ADD_STREAM;
 157                 lum.u.stream.channel_key = usess->metadata->obj->shm_fd;
 158                 lum.u.stream.stream_key = usess->metadata->stream_obj->shm_fd;
 159                 lum.u.stream.state = LTTNG_CONSUMER_ACTIVE_STREAM;
 160                 lum.u.stream.output = DEFAULT_UST_CHANNEL_OUTPUT;
 161                 lum.u.stream.mmap_len = usess->metadata->stream_obj->memory_map_size;
 162                 lum.u.stream.uid = usess->uid;
 163                 lum.u.stream.gid = usess->gid;
 164                 strncpy(lum.u.stream.path_name, usess->metadata->pathname, PATH_MAX - 1);
 165                 lum.u.stream.path_name[PATH_MAX - 1] = '\0';
 166                 DBG("Sending metadata stream %d to consumer", lum.u.stream.stream_key);
 167                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
 168                 if (ret < 0) {
 169                         PERROR("send consumer metadata stream");
 170                         goto error;
 171                 }
 172                 fds[0] = usess->metadata->stream_obj->shm_fd;
 173                 fds[1] = usess->metadata->stream_obj->wait_fd;
 174                 ret = lttcomm_send_fds_unix_sock(sock, fds, 2);
 175                 if (ret < 0) {
 176                         PERROR("send consumer stream");
 177                         goto error;
 178                 }
 179         }
 180
 181         /* Send each channel fd streams of session */
 182         rcu_read_lock();
 183         cds_lfht_for_each_entry(usess->channels->ht, &iter.iter, ua_chan,
 184                         node.node) {
 185                 /*
 186                  * Indicate that the channel was not created on the tracer side so skip
 187                  * sending unexisting streams.
 188                  */
 189                 if (ua_chan->obj == NULL) {
 190                         continue;
 191                 }
 192
 193                 ret = send_channel_streams(sock, ua_chan, usess->uid, usess->gid);
 194                 if (ret < 0) {
 195                         rcu_read_unlock();
 196                         goto error;
 197                 }
 198         }
 199         rcu_read_unlock();
 200
 201         DBG("consumer fds (metadata and channel streams) sent");
 202
 203         return 0;
 204
 205 error:
 206         return ret;
 207 }