Cleanup: arm sys_mmap whitespace
[lttng-modules.git] / lttng-context-ppid.c
1 /*
2 * lttng-context-ppid.c
3 *
4 * LTTng PPID 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 <linux/syscalls.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 static
33 size_t ppid_get_size(size_t offset)
34 {
35 size_t size = 0;
36
37 size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
38 size += sizeof(pid_t);
39 return size;
40 }
41
42 static
43 void ppid_record(struct lttng_ctx_field *field,
44 struct lib_ring_buffer_ctx *ctx,
45 struct lttng_channel *chan)
46 {
47 pid_t ppid;
48
49
50 /*
51 * TODO: when we eventually add RCU subsystem instrumentation,
52 * taking the rcu read lock here will trigger RCU tracing
53 * recursively. We should modify the kernel synchronization so
54 * it synchronizes both for RCU and RCU sched, and rely on
55 * rcu_read_lock_sched_notrace.
56 */
57
58 rcu_read_lock();
59 ppid = task_tgid_nr(current->real_parent);
60 rcu_read_unlock();
61 lib_ring_buffer_align_ctx(ctx, lttng_alignof(ppid));
62 chan->ops->event_write(ctx, &ppid, sizeof(ppid));
63 }
64
65 int lttng_add_ppid_to_ctx(struct lttng_ctx **ctx)
66 {
67 struct lttng_ctx_field *field;
68
69 field = lttng_append_context(ctx);
70 if (!field)
71 return -ENOMEM;
72 if (lttng_find_context(*ctx, "ppid")) {
73 lttng_remove_context_field(ctx, field);
74 return -EEXIST;
75 }
76 field->event_field.name = "ppid";
77 field->event_field.type.atype = atype_integer;
78 field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
79 field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
80 field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
81 field->event_field.type.u.basic.integer.reverse_byte_order = 0;
82 field->event_field.type.u.basic.integer.base = 10;
83 field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
84 field->get_size = ppid_get_size;
85 field->record = ppid_record;
86 wrapper_vmalloc_sync_all();
87 return 0;
88 }
89 EXPORT_SYMBOL_GPL(lttng_add_ppid_to_ctx);
90
91 MODULE_LICENSE("GPL and additional rights");
92 MODULE_AUTHOR("Mathieu Desnoyers");
93 MODULE_DESCRIPTION("Linux Trace Toolkit PPID Context");
This page took 0.031471 seconds and 4 git commands to generate.