Fix: pid tracker should track "pgid"
[deliverable/lttng-modules.git] / lttng-context-vtid.c
1 /*
2 * lttng-context-vtid.c
3 *
4 * LTTng vTID 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 vtid_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 vtid_record(struct lttng_ctx_field *field,
43 struct lib_ring_buffer_ctx *ctx,
44 struct lttng_channel *chan)
45 {
46 pid_t vtid;
47
48 /*
49 * nsproxy can be NULL when scheduled out of exit.
50 */
51 if (!current->nsproxy)
52 vtid = 0;
53 else
54 vtid = task_pid_vnr(current);
55 lib_ring_buffer_align_ctx(ctx, lttng_alignof(vtid));
56 chan->ops->event_write(ctx, &vtid, sizeof(vtid));
57 }
58
59 static
60 void vtid_get_value(struct lttng_ctx_field *field,
61 struct lttng_probe_ctx *lttng_probe_ctx,
62 union lttng_ctx_value *value)
63 {
64 pid_t vtid;
65
66 /*
67 * nsproxy can be NULL when scheduled out of exit.
68 */
69 if (!current->nsproxy)
70 vtid = 0;
71 else
72 vtid = task_pid_vnr(current);
73 value->s64 = vtid;
74 }
75
76 int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
77 {
78 struct lttng_ctx_field *field;
79
80 field = lttng_append_context(ctx);
81 if (!field)
82 return -ENOMEM;
83 if (lttng_find_context(*ctx, "vtid")) {
84 lttng_remove_context_field(ctx, field);
85 return -EEXIST;
86 }
87 field->event_field.name = "vtid";
88 field->event_field.type.atype = atype_integer;
89 field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
90 field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
91 field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
92 field->event_field.type.u.basic.integer.reverse_byte_order = 0;
93 field->event_field.type.u.basic.integer.base = 10;
94 field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
95 field->get_size = vtid_get_size;
96 field->record = vtid_record;
97 field->get_value = vtid_get_value;
98 lttng_context_update(*ctx);
99 wrapper_vmalloc_sync_all();
100 return 0;
101 }
102 EXPORT_SYMBOL_GPL(lttng_add_vtid_to_ctx);
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