[lttng-modules.git] / lttng-context-cgroup-ns.c

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-context-cgroup-ns.c
 *
 * LTTng cgroup namespace context.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *               2019 Michael Jeanson <mjeanson@efficios.com>
 *
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/cgroup.h>
#include <lttng-events.h>
#include <wrapper/ringbuffer/frontend_types.h>
#include <wrapper/namespace.h>
#include <lttng-tracer.h>

#if defined(CONFIG_CGROUPS) && \
	((LINUX_VERSION_CODE >= KERNEL_VERSION(4,6,0)) || \
	 LTTNG_UBUNTU_KERNEL_RANGE(4,4,0,0, 4,5,0,0))

static
size_t cgroup_ns_get_size(size_t offset)
{
	size_t size = 0;

	size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int));
	size += sizeof(unsigned int);
	return size;
}

static
void cgroup_ns_record(struct lttng_ctx_field *field,
		 struct lib_ring_buffer_ctx *ctx,
		 struct lttng_channel *chan)
{
	unsigned int cgroup_ns_inum = 0;

	/*
	 * nsproxy can be NULL when scheduled out of exit.
	 *
	 * As documented in 'linux/nsproxy.h' namespaces access rules, no
	 * precautions should be taken when accessing the current task's
	 * namespaces, just dereference the pointers.
	 */
	if (current->nsproxy)
		cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum;

	lib_ring_buffer_align_ctx(ctx, lttng_alignof(cgroup_ns_inum));
	chan->ops->event_write(ctx, &cgroup_ns_inum, sizeof(cgroup_ns_inum));
}

static
void cgroup_ns_get_value(struct lttng_ctx_field *field,
		struct lttng_probe_ctx *lttng_probe_ctx,
		union lttng_ctx_value *value)
{
	unsigned int cgroup_ns_inum = 0;

	/*
	 * nsproxy can be NULL when scheduled out of exit.
	 *
	 * As documented in 'linux/nsproxy.h' namespaces access rules, no
	 * precautions should be taken when accessing the current task's
	 * namespaces, just dereference the pointers.
	 */
	if (current->nsproxy)
		cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum;

	value->s64 = cgroup_ns_inum;
}

int lttng_add_cgroup_ns_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, "cgroup_ns")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "cgroup_ns";
	field->event_field.type.atype = atype_integer;
	field->event_field.type.u.integer.size = sizeof(unsigned int) * CHAR_BIT;
	field->event_field.type.u.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT;
	field->event_field.type.u.integer.signedness = lttng_is_signed_type(unsigned int);
	field->event_field.type.u.integer.reverse_byte_order = 0;
	field->event_field.type.u.integer.base = 10;
	field->event_field.type.u.integer.encoding = lttng_encode_none;
	field->get_size = cgroup_ns_get_size;
	field->record = cgroup_ns_record;
	field->get_value = cgroup_ns_get_value;
	lttng_context_update(*ctx);
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_cgroup_ns_to_ctx);

#endif
Commit	Line	Data
b7cdc182	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
a6cf40a4 MJ	2	*
	3	* lttng-context-cgroup-ns.c
	4	*
	5	* LTTng cgroup namespace context.
	6	*
	7	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	* 2019 Michael Jeanson <mjeanson@efficios.com>
	9	*
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/slab.h>
	14	#include <linux/sched.h>
	15	#include <linux/cgroup.h>
	16	#include <lttng-events.h>
	17	#include <wrapper/ringbuffer/frontend_types.h>
a6cf40a4 MJ	18	#include <wrapper/namespace.h>
	19	#include <lttng-tracer.h>
	20
	21	#if defined(CONFIG_CGROUPS) && \
	22	((LINUX_VERSION_CODE >= KERNEL_VERSION(4,6,0)) \|\| \
	23	LTTNG_UBUNTU_KERNEL_RANGE(4,4,0,0, 4,5,0,0))
	24
	25	static
	26	size_t cgroup_ns_get_size(size_t offset)
	27	{
	28	size_t size = 0;
	29
	30	size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int));
	31	size += sizeof(unsigned int);
	32	return size;
	33	}
	34
	35	static
	36	void cgroup_ns_record(struct lttng_ctx_field *field,
	37	struct lib_ring_buffer_ctx *ctx,
	38	struct lttng_channel *chan)
	39	{
	40	unsigned int cgroup_ns_inum = 0;
	41
	42	/*
	43	* nsproxy can be NULL when scheduled out of exit.
	44	*
	45	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	46	* precautions should be taken when accessing the current task's
	47	* namespaces, just dereference the pointers.
	48	*/
	49	if (current->nsproxy)
	50	cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum;
	51
	52	lib_ring_buffer_align_ctx(ctx, lttng_alignof(cgroup_ns_inum));
	53	chan->ops->event_write(ctx, &cgroup_ns_inum, sizeof(cgroup_ns_inum));
	54	}
	55
	56	static
	57	void cgroup_ns_get_value(struct lttng_ctx_field *field,
	58	struct lttng_probe_ctx *lttng_probe_ctx,
	59	union lttng_ctx_value *value)
	60	{
	61	unsigned int cgroup_ns_inum = 0;
	62
	63	/*
	64	* nsproxy can be NULL when scheduled out of exit.
	65	*
	66	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	67	* precautions should be taken when accessing the current task's
	68	* namespaces, just dereference the pointers.
	69	*/
	70	if (current->nsproxy)
	71	cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum;
	72
	73	value->s64 = cgroup_ns_inum;
	74	}
	75
	76	int lttng_add_cgroup_ns_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, "cgroup_ns")) {
84	lttng_remove_context_field(ctx, field);
85	return -EEXIST;
86	}
87	field->event_field.name = "cgroup_ns";
88	field->event_field.type.atype = atype_integer;
ceabb767 MD	89	field->event_field.type.u.integer.size = sizeof(unsigned int) * CHAR_BIT;
	90	field->event_field.type.u.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT;
	91	field->event_field.type.u.integer.signedness = lttng_is_signed_type(unsigned int);
	92	field->event_field.type.u.integer.reverse_byte_order = 0;
	93	field->event_field.type.u.integer.base = 10;
	94	field->event_field.type.u.integer.encoding = lttng_encode_none;
a6cf40a4 MJ	95	field->get_size = cgroup_ns_get_size;
	96	field->record = cgroup_ns_record;
	97	field->get_value = cgroup_ns_get_value;
	98	lttng_context_update(*ctx);
a6cf40a4 MJ	99	return 0;
	100	}
	101	EXPORT_SYMBOL_GPL(lttng_add_cgroup_ns_to_ctx);
	102
	103	#endif