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-ht.h>
  27 #include <lttng-share.h>
  28 #include <lttng-sessiond-comm.h>
  29 #include <lttng/lttng-consumer.h>
  30
  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                 uid_t uid, gid_t gid)
  39 {
  40         int ret, fd;
  41         struct lttcomm_consumer_msg lum;
  42         struct ltt_ust_stream *stream, *tmp;
  43
  44         DBG("Sending streams of channel %s to UST consumer", uchan->name);
  45
  46         /* Send channel */
  47         lum.cmd_type = LTTNG_CONSUMER_ADD_CHANNEL;
  48
  49         /*
  50          * We need to keep shm_fd open while we transfer the stream file
  51          * descriptors to make sure this key stays unique within the
  52          * session daemon. We can free the channel shm_fd without
  53          * problem after we finished sending stream fds for that
  54          * channel.
  55          */
  56         lum.u.channel.channel_key = uchan->obj->shm_fd;
  57         lum.u.channel.max_sb_size = uchan->attr.subbuf_size;
  58         lum.u.channel.mmap_len = uchan->obj->memory_map_size;
  59         DBG("Sending channel %d to consumer", lum.u.channel.channel_key);
  60         ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
  61         if (ret < 0) {
  62                 perror("send consumer channel");
  63                 goto error;
  64         }
  65         fd = uchan->obj->shm_fd;
  66         ret = lttcomm_send_fds_unix_sock(sock, &fd, 1);
  67         if (ret < 0) {
  68                 perror("send consumer channel ancillary data");
  69                 goto error;
  70         }
  71
  72         cds_list_for_each_entry_safe(stream, tmp, &uchan->streams.head, list) {
  73                 int fds[2];
  74
  75                 if (!stream->obj->shm_fd) {
  76                         continue;
  77                 }
  78                 lum.cmd_type = LTTNG_CONSUMER_ADD_STREAM;
  79                 lum.u.stream.channel_key = uchan->obj->shm_fd;
  80                 lum.u.stream.stream_key = stream->obj->shm_fd;
  81                 lum.u.stream.state = LTTNG_CONSUMER_ACTIVE_STREAM;
  82                 /*
  83                  * FIXME Hack alert! we force MMAP for now. Mixup
  84                  * between EVENT and UST enums elsewhere.
  85                  */
  86                 lum.u.stream.output = DEFAULT_UST_CHANNEL_OUTPUT;
  87                 lum.u.stream.mmap_len = stream->obj->memory_map_size;
  88                 lum.u.stream.uid = uid;
  89                 lum.u.stream.gid = gid;
  90                 strncpy(lum.u.stream.path_name, stream->pathname, PATH_MAX - 1);
  91                 lum.u.stream.path_name[PATH_MAX - 1] = '\0';
  92                 DBG("Sending stream %d to consumer", lum.u.stream.stream_key);
  93                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
  94                 if (ret < 0) {
  95                         perror("send consumer stream");
  96                         goto error;
  97                 }
  98
  99                 fds[0] = stream->obj->shm_fd;
 100                 fds[1] = stream->obj->wait_fd;
 101                 ret = lttcomm_send_fds_unix_sock(sock, fds, 2);
 102                 if (ret < 0) {
 103                         perror("send consumer stream ancillary data");
 104                         goto error;
 105                 }
 106         }
 107
 108         DBG("consumer channel streams sent");
 109
 110         return 0;
 111
 112 error:
 113         return ret;
 114 }
 115
 116 /*
 117  * Send all stream fds of the UST session to the consumer.
 118  */
 119 int ust_consumer_send_session(int consumer_fd, struct ust_app_session *usess)
 120 {
 121         int ret = 0;
 122         int sock = consumer_fd;
 123         struct lttng_ht_iter iter;
 124         struct lttcomm_consumer_msg lum;
 125         struct ust_app_channel *ua_chan;
 126
 127         DBG("Sending metadata stream fd");
 128
 129         if (consumer_fd < 0) {
 130                 ERR("Consumer has negative file descriptor");
 131                 return -EINVAL;
 132         }
 133
 134         if (usess->metadata->obj->shm_fd != 0) {
 135                 int fd;
 136                 int fds[2];
 137
 138                 /* Send metadata channel fd */
 139                 lum.cmd_type = LTTNG_CONSUMER_ADD_CHANNEL;
 140                 lum.u.channel.channel_key = usess->metadata->obj->shm_fd;
 141                 lum.u.channel.max_sb_size = usess->metadata->attr.subbuf_size;
 142                 lum.u.channel.mmap_len = usess->metadata->obj->memory_map_size;
 143                 DBG("Sending metadata channel %d to consumer", lum.u.channel.channel_key);
 144                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
 145                 if (ret < 0) {
 146                         perror("send consumer channel");
 147                         goto error;
 148                 }
 149                 fd = usess->metadata->obj->shm_fd;
 150                 ret = lttcomm_send_fds_unix_sock(sock, &fd, 1);
 151                 if (ret < 0) {
 152                         perror("send consumer metadata channel");
 153                         goto error;
 154                 }
 155
 156                 /* Send metadata stream fd */
 157                 lum.cmd_type = LTTNG_CONSUMER_ADD_STREAM;
 158                 lum.u.stream.channel_key = usess->metadata->obj->shm_fd;
 159                 lum.u.stream.stream_key = usess->metadata->stream_obj->shm_fd;
 160                 lum.u.stream.state = LTTNG_CONSUMER_ACTIVE_STREAM;
 161                 lum.u.stream.output = DEFAULT_UST_CHANNEL_OUTPUT;
 162                 lum.u.stream.mmap_len = usess->metadata->stream_obj->memory_map_size;
 163                 lum.u.stream.uid = usess->uid;
 164                 lum.u.stream.gid = usess->gid;
 165                 strncpy(lum.u.stream.path_name, usess->metadata->pathname, PATH_MAX - 1);
 166                 lum.u.stream.path_name[PATH_MAX - 1] = '\0';
 167                 DBG("Sending metadata stream %d to consumer", lum.u.stream.stream_key);
 168                 ret = lttcomm_send_unix_sock(sock, &lum, sizeof(lum));
 169                 if (ret < 0) {
 170                         perror("send consumer metadata stream");
 171                         goto error;
 172                 }
 173                 fds[0] = usess->metadata->stream_obj->shm_fd;
 174                 fds[1] = usess->metadata->stream_obj->wait_fd;
 175                 ret = lttcomm_send_fds_unix_sock(sock, fds, 2);
 176                 if (ret < 0) {
 177                         perror("send consumer stream");
 178                         goto error;
 179                 }
 180         }
 181
 182         /* Send each channel fd streams of session */
 183         rcu_read_lock();
 184         cds_lfht_for_each_entry(usess->channels->ht, &iter.iter, ua_chan,
 185                         node.node) {
 186                 ret = send_channel_streams(sock, ua_chan, usess->uid, usess->gid);
 187                 if (ret < 0) {
 188                         rcu_read_unlock();
 189                         goto error;
 190                 }
 191         }
 192         rcu_read_unlock();
 193
 194         DBG("consumer fds (metadata and channel streams) sent");
 195
 196         return 0;
 197
 198 error:
 199         return ret;
 200 }