/usr/src/lttng-modules-2.7.1/lttng-context-vppid.c is in lttng-modules-dkms 2.7.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 | /*
* lttng-context-vppid.c
*
* LTTng vPPID context.
*
* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; only
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include "lttng-events.h"
#include "wrapper/ringbuffer/frontend_types.h"
#include "wrapper/vmalloc.h"
#include "lttng-tracer.h"
static
size_t vppid_get_size(size_t offset)
{
size_t size = 0;
size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
size += sizeof(pid_t);
return size;
}
static
void vppid_record(struct lttng_ctx_field *field,
struct lib_ring_buffer_ctx *ctx,
struct lttng_channel *chan)
{
struct task_struct *parent;
pid_t vppid;
/*
* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
* the current thread nsproxy to perform the lookup.
*/
/*
* TODO: when we eventually add RCU subsystem instrumentation,
* taking the rcu read lock here will trigger RCU tracing
* recursively. We should modify the kernel synchronization so
* it synchronizes both for RCU and RCU sched, and rely on
* rcu_read_lock_sched_notrace.
*/
rcu_read_lock();
parent = rcu_dereference(current->real_parent);
if (!current->nsproxy)
vppid = 0;
else
vppid = task_tgid_vnr(parent);
rcu_read_unlock();
lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
chan->ops->event_write(ctx, &vppid, sizeof(vppid));
}
static
void vppid_get_value(struct lttng_ctx_field *field,
union lttng_ctx_value *value)
{
struct task_struct *parent;
pid_t vppid;
/*
* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
* the current thread nsproxy to perform the lookup.
*/
/*
* TODO: when we eventually add RCU subsystem instrumentation,
* taking the rcu read lock here will trigger RCU tracing
* recursively. We should modify the kernel synchronization so
* it synchronizes both for RCU and RCU sched, and rely on
* rcu_read_lock_sched_notrace.
*/
rcu_read_lock();
parent = rcu_dereference(current->real_parent);
if (!current->nsproxy)
vppid = 0;
else
vppid = task_tgid_vnr(parent);
rcu_read_unlock();
value->s64 = vppid;
}
int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
{
struct lttng_ctx_field *field;
field = lttng_append_context(ctx);
if (!field)
return -ENOMEM;
if (lttng_find_context(*ctx, "vppid")) {
lttng_remove_context_field(ctx, field);
return -EEXIST;
}
field->event_field.name = "vppid";
field->event_field.type.atype = atype_integer;
field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
field->event_field.type.u.basic.integer.reverse_byte_order = 0;
field->event_field.type.u.basic.integer.base = 10;
field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
field->get_size = vppid_get_size;
field->record = vppid_record;
field->get_value = vppid_get_value;
lttng_context_update(*ctx);
wrapper_vmalloc_sync_all();
return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);
MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Linux Trace Toolkit vPPID Context");
MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
__stringify(LTTNG_MODULES_MINOR_VERSION) "."
__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
LTTNG_MODULES_EXTRAVERSION);
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