Fix: Add statedump exit so module is not permanent
[lttng-modules.git] / lttng-context-pid.c
1 /*
2 * lttng-context-pid.c
3 *
4 * LTTng PID context.
5 *
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
21 */
22
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/sched.h>
26 #include "lttng-events.h"
27 #include "wrapper/ringbuffer/frontend_types.h"
28 #include "wrapper/vmalloc.h"
29 #include "lttng-tracer.h"
30
31 static
32 size_t pid_get_size(size_t offset)
33 {
34 size_t size = 0;
35
36 size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
37 size += sizeof(pid_t);
38 return size;
39 }
40
41 static
42 void pid_record(struct lttng_ctx_field *field,
43 struct lib_ring_buffer_ctx *ctx,
44 struct lttng_channel *chan)
45 {
46 pid_t pid;
47
48 pid = task_tgid_nr(current);
49 lib_ring_buffer_align_ctx(ctx, lttng_alignof(pid));
50 chan->ops->event_write(ctx, &pid, sizeof(pid));
51 }
52
53 int lttng_add_pid_to_ctx(struct lttng_ctx **ctx)
54 {
55 struct lttng_ctx_field *field;
56
57 field = lttng_append_context(ctx);
58 if (!field)
59 return -ENOMEM;
60 if (lttng_find_context(*ctx, "pid")) {
61 lttng_remove_context_field(ctx, field);
62 return -EEXIST;
63 }
64 field->event_field.name = "pid";
65 field->event_field.type.atype = atype_integer;
66 field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
67 field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
68 field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
69 field->event_field.type.u.basic.integer.reverse_byte_order = 0;
70 field->event_field.type.u.basic.integer.base = 10;
71 field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
72 field->get_size = pid_get_size;
73 field->record = pid_record;
74 wrapper_vmalloc_sync_all();
75 return 0;
76 }
77 EXPORT_SYMBOL_GPL(lttng_add_pid_to_ctx);
78
79 MODULE_LICENSE("GPL and additional rights");
80 MODULE_AUTHOR("Mathieu Desnoyers");
81 MODULE_DESCRIPTION("Linux Trace Toolkit PID Context");
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