lttng-context-interruptible.c

   1 /*
   2  * lttng-context-interruptible.c
   3  *
   4  * LTTng interruptible context.
   5  *
   6  * Copyright (C) 2009-2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/sched.h>
  26 #include <linux/irqflags.h>
  27 #include <lttng-events.h>
  28 #include <wrapper/ringbuffer/frontend_types.h>
  29 #include <wrapper/vmalloc.h>
  30 #include <lttng-tracer.h>
  31
  32 /*
  33  * Interruptible at value -1 means "unknown".
  34  */
  35
  36 static
  37 size_t interruptible_get_size(size_t offset)
  38 {
  39         size_t size = 0;
  40
  41         size += lib_ring_buffer_align(offset, lttng_alignof(int8_t));
  42         size += sizeof(int8_t);
  43         return size;
  44 }
  45
  46 static
  47 void interruptible_record(struct lttng_ctx_field *field,
  48                 struct lib_ring_buffer_ctx *ctx,
  49                 struct lttng_channel *chan)
  50 {
  51         struct lttng_probe_ctx *lttng_probe_ctx = ctx->priv;
  52         int8_t interruptible = lttng_probe_ctx->interruptible;
  53
  54         lib_ring_buffer_align_ctx(ctx, lttng_alignof(interruptible));
  55         chan->ops->event_write(ctx, &interruptible, sizeof(interruptible));
  56 }
  57
  58 static
  59 void interruptible_get_value(struct lttng_ctx_field *field,
  60                 struct lttng_probe_ctx *lttng_probe_ctx,
  61                 union lttng_ctx_value *value)
  62 {
  63         int8_t interruptible = lttng_probe_ctx->interruptible;
  64
  65         value->s64 = interruptible;
  66 }
  67
  68 int lttng_add_interruptible_to_ctx(struct lttng_ctx **ctx)
  69 {
  70         struct lttng_ctx_field *field;
  71
  72         field = lttng_append_context(ctx);
  73         if (!field)
  74                 return -ENOMEM;
  75         if (lttng_find_context(*ctx, "interruptible")) {
  76                 lttng_remove_context_field(ctx, field);
  77                 return -EEXIST;
  78         }
  79         field->event_field.name = "interruptible";
  80         field->event_field.type.atype = atype_integer;
  81         field->event_field.type.u.basic.integer.size = sizeof(int8_t) * CHAR_BIT;
  82         field->event_field.type.u.basic.integer.alignment = lttng_alignof(int8_t) * CHAR_BIT;
  83         field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(int8_t);
  84         field->event_field.type.u.basic.integer.reverse_byte_order = 0;
  85         field->event_field.type.u.basic.integer.base = 10;
  86         field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
  87         field->get_size = interruptible_get_size;
  88         field->record = interruptible_record;
  89         field->get_value = interruptible_get_value;
  90         lttng_context_update(*ctx);
  91         wrapper_vmalloc_sync_all();
  92         return 0;
  93 }
  94 EXPORT_SYMBOL_GPL(lttng_add_interruptible_to_ctx);