ltt-sessiond/kernel-ctl.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
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #include <errno.h>
  20 #include <stdlib.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23
  24 #include "ltt-sessiond.h"
  25 #include "libkernelctl.h"
  26 #include "kernel-ctl.h"
  27 #include "trace.h"
  28
  29 /*
  30  *  kernel_create_session
  31  *
  32  *  Create a new kernel session using the command context session.
  33  */
  34 int kernel_create_session(struct command_ctx *cmd_ctx, int tracer_fd)
  35 {
  36         int ret;
  37         struct ltt_kernel_session *lks;
  38
  39         /* Allocate a new kernel session */
  40         lks = malloc(sizeof(struct ltt_kernel_session));
  41         if (lks == NULL) {
  42                 perror("kernel session malloc");
  43                 ret = -errno;
  44                 goto error;
  45         }
  46
  47         ret = kernctl_create_session(tracer_fd);
  48         if (ret < 0) {
  49                 goto error;
  50         }
  51
  52         /* Assigning session fd and to the command context */
  53         lks->fd = ret;
  54         cmd_ctx->session->kernel_session = lks;
  55         cmd_ctx->session->kern_session_count++;
  56
  57         return 0;
  58
  59 error:
  60         return ret;
  61 }
  62
  63 /*
  64  *  kernel_create_channel
  65  *
  66  *  Create a kernel channel within the kernel session.
  67  */
  68 int kernel_create_channel(struct command_ctx *cmd_ctx)
  69 {
  70         int ret;
  71         struct ltt_kernel_channel *lkc;
  72         struct lttng_kernel_channel *chan;
  73
  74         lkc = malloc(sizeof(struct ltt_kernel_channel));
  75         chan = malloc(sizeof(struct lttng_kernel_channel));
  76
  77         if (lkc == NULL || chan == NULL) {
  78                 perror("kernel channel malloc");
  79                 ret = -errno;
  80                 goto error;
  81         }
  82
  83         chan->overwrite = DEFAULT_KERNEL_OVERWRITE;
  84         chan->subbuf_size = DEFAULT_KERNEL_SUBBUF_SIZE;
  85         chan->num_subbuf = DEFAULT_KERNEL_SUBBUF_NUM;
  86         chan->switch_timer_interval = DEFAULT_KERNEL_SWITCH_TIMER;
  87         chan->read_timer_interval = DEFAULT_KERNEL_READ_TIMER;
  88
  89         ret = kernctl_create_channel(cmd_ctx->session->kernel_session->fd, chan);
  90         if (ret < 0) {
  91                 perror("ioctl create channel");
  92                 goto error;
  93         }
  94
  95         lkc->fd = ret;
  96         lkc->channel = chan;
  97         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
  98
  99         cmd_ctx->session->kernel_session->channel = lkc;
 100
 101         return 0;
 102
 103 error:
 104         return ret;
 105 }
 106
 107 /*
 108  *  kernel_enable_event
 109  *
 110  *  Enable kernel event.
 111  */
 112 int kernel_enable_event(struct ltt_kernel_channel *channel, char *name)
 113 {
 114         int ret;
 115         struct ltt_kernel_event *event;
 116         struct lttng_kernel_event *lke;
 117
 118         event = malloc(sizeof(struct ltt_kernel_event));
 119         lke = malloc(sizeof(struct lttng_kernel_event));
 120
 121         if (event == NULL || lke == NULL) {
 122                 perror("kernel enable event malloc");
 123                 ret = -errno;
 124                 goto error;
 125         }
 126
 127         /* Setting up a kernel event */
 128         strncpy(lke->name, name, LTTNG_SYM_NAME_LEN);
 129         lke->instrumentation = LTTNG_KERNEL_TRACEPOINTS;
 130         event->event = lke;
 131
 132         ret = kernctl_create_event(channel->fd, lke);
 133         if (ret < 0) {
 134                 goto error;
 135         }
 136
 137         /* Add event to event list */
 138         cds_list_add(&event->list, &channel->events_list.head);
 139
 140         return 0;
 141
 142 error:
 143         return ret;
 144 }
 145
 146 /*
 147  *  kernel_open_metadata
 148  *
 149  *  Open metadata stream.
 150  */
 151 int kernel_open_metadata(struct ltt_kernel_session *session)
 152 {
 153         int ret;
 154         struct ltt_kernel_metadata *lkm;
 155         struct lttng_kernel_channel *conf;
 156
 157         lkm = malloc(sizeof(struct ltt_kernel_metadata));
 158         conf = malloc(sizeof(struct lttng_kernel_channel));
 159
 160         if (lkm == NULL || conf == NULL) {
 161                 perror("kernel open metadata malloc");
 162                 ret = -errno;
 163                 goto error;
 164         }
 165
 166         conf->overwrite = DEFAULT_KERNEL_OVERWRITE;
 167         conf->subbuf_size = DEFAULT_KERNEL_SUBBUF_SIZE;
 168         conf->num_subbuf = DEFAULT_KERNEL_SUBBUF_NUM;
 169         conf->switch_timer_interval = DEFAULT_KERNEL_SWITCH_TIMER;
 170         conf->read_timer_interval = DEFAULT_KERNEL_READ_TIMER;
 171
 172         ret = kernctl_open_metadata(session->fd, conf);
 173         if (ret < 0) {
 174                 goto error;
 175         }
 176
 177         session->metadata = lkm;
 178         session->metadata->fd = ret;
 179         session->metadata->conf = conf;
 180
 181         return 0;
 182
 183 error:
 184         return ret;
 185 }