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                 goto error;
  92         }
  93
  94         lkc->fd = ret;
  95         lkc->channel = chan;
  96         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
  97
  98         cmd_ctx->session->kernel_session->channel = lkc;
  99
 100         return 0;
 101
 102 error:
 103         return ret;
 104 }
 105
 106 /*
 107  *  kernel_enable_event
 108  *
 109  *  Enable kernel event.
 110  */
 111 int kernel_enable_event(struct ltt_kernel_channel *channel, char *name)
 112 {
 113         int ret;
 114         struct ltt_kernel_event *event;
 115         struct lttng_kernel_event *lke;
 116
 117         event = malloc(sizeof(struct ltt_kernel_event));
 118         lke = malloc(sizeof(struct lttng_kernel_event));
 119
 120         if (event == NULL || lke == NULL) {
 121                 perror("kernel enable event malloc");
 122                 ret = -errno;
 123                 goto error;
 124         }
 125
 126         /* Setting up a kernel event */
 127         strncpy(lke->name, name, LTTNG_SYM_NAME_LEN);
 128         lke->instrumentation = LTTNG_KERNEL_TRACEPOINTS;
 129         event->event = lke;
 130
 131         ret = kernctl_create_event(channel->fd, lke);
 132         if (ret < 0) {
 133                 goto error;
 134         }
 135
 136         /* Add event to event list */
 137         cds_list_add(&event->list, &channel->events_list.head);
 138
 139         return 0;
 140
 141 error:
 142         return ret;
 143 }