Version 2.4.4
[lttng-modules.git] / lttng-context-vpid.c
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b64bc438 1/*
886d51a3 2 * lttng-context-vpid.c
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3 *
4 * LTTng vPID context.
5 *
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6 * Copyright (C) 2009-2012 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
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21 */
22
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/sched.h>
a90917c3 26#include "lttng-events.h"
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27#include "wrapper/ringbuffer/frontend_types.h"
28#include "wrapper/vmalloc.h"
a90917c3 29#include "lttng-tracer.h"
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30
31static
32size_t vpid_get_size(size_t offset)
33{
34 size_t size = 0;
35
a90917c3 36 size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
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37 size += sizeof(pid_t);
38 return size;
39}
40
41static
42void vpid_record(struct lttng_ctx_field *field,
43 struct lib_ring_buffer_ctx *ctx,
a90917c3 44 struct lttng_channel *chan)
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45{
46 pid_t vpid;
47
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48 /*
49 * nsproxy can be NULL when scheduled out of exit.
50 */
51 if (!current->nsproxy)
52 vpid = 0;
53 else
54 vpid = task_tgid_vnr(current);
a90917c3 55 lib_ring_buffer_align_ctx(ctx, lttng_alignof(vpid));
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56 chan->ops->event_write(ctx, &vpid, sizeof(vpid));
57}
58
59int lttng_add_vpid_to_ctx(struct lttng_ctx **ctx)
60{
61 struct lttng_ctx_field *field;
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62
63 field = lttng_append_context(ctx);
64 if (!field)
09fec6b4 65 return -ENOMEM;
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66 if (lttng_find_context(*ctx, "vpid")) {
67 lttng_remove_context_field(ctx, field);
68 return -EEXIST;
69 }
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70 field->event_field.name = "vpid";
71 field->event_field.type.atype = atype_integer;
72 field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
a90917c3 73 field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
06254b0f 74 field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
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75 field->event_field.type.u.basic.integer.reverse_byte_order = 0;
76 field->event_field.type.u.basic.integer.base = 10;
77 field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
78 field->get_size = vpid_get_size;
79 field->record = vpid_record;
338e5cc9 80 lttng_context_update(*ctx);
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81 wrapper_vmalloc_sync_all();
82 return 0;
83}
84EXPORT_SYMBOL_GPL(lttng_add_vpid_to_ctx);
85
86MODULE_LICENSE("GPL and additional rights");
87MODULE_AUTHOR("Mathieu Desnoyers");
88MODULE_DESCRIPTION("Linux Trace Toolkit vPID Context");
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89MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
90 __stringify(LTTNG_MODULES_MINOR_VERSION) "."
91 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
92 LTTNG_MODULES_EXTRAVERSION);
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