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

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-context-uts-ns.c
 *
 * LTTng uts 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/utsname.h>
#include <lttng-events.h>
#include <wrapper/ringbuffer/frontend_types.h>
#include <wrapper/namespace.h>
#include <lttng-tracer.h>

#if defined(CONFIG_UTS_NS) && \
	(LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0))

static
size_t uts_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 uts_ns_record(struct lttng_ctx_field *field,
		 struct lib_ring_buffer_ctx *ctx,
		 struct lttng_channel *chan)
{
	unsigned int uts_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)
		uts_ns_inum = current->nsproxy->uts_ns->lttng_ns_inum;

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

static
void uts_ns_get_value(struct lttng_ctx_field *field,
		struct lttng_probe_ctx *lttng_probe_ctx,
		union lttng_ctx_value *value)
{
	unsigned int uts_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)
		uts_ns_inum = current->nsproxy->uts_ns->lttng_ns_inum;

	value->s64 = uts_ns_inum;
}

int lttng_add_uts_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, "uts_ns")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "uts_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 = uts_ns_get_size;
	field->record = uts_ns_record;
	field->get_value = uts_ns_get_value;
	lttng_context_update(*ctx);
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_uts_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-uts-ns.c
	4	*
	5	* LTTng uts 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/utsname.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_UTS_NS) && \
	22	(LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0))
	23
	24	static
	25	size_t uts_ns_get_size(size_t offset)
	26	{
	27	size_t size = 0;
	28
	29	size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int));
	30	size += sizeof(unsigned int);
	31	return size;
	32	}
	33
	34	static
	35	void uts_ns_record(struct lttng_ctx_field *field,
	36	struct lib_ring_buffer_ctx *ctx,
	37	struct lttng_channel *chan)
	38	{
	39	unsigned int uts_ns_inum = 0;
	40
	41	/*
	42	* nsproxy can be NULL when scheduled out of exit.
	43	*
	44	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	45	* precautions should be taken when accessing the current task's
	46	* namespaces, just dereference the pointers.
	47	*/
	48	if (current->nsproxy)
	49	uts_ns_inum = current->nsproxy->uts_ns->lttng_ns_inum;
	50
	51	lib_ring_buffer_align_ctx(ctx, lttng_alignof(uts_ns_inum));
	52	chan->ops->event_write(ctx, &uts_ns_inum, sizeof(uts_ns_inum));
	53	}
	54
	55	static
	56	void uts_ns_get_value(struct lttng_ctx_field *field,
	57	struct lttng_probe_ctx *lttng_probe_ctx,
	58	union lttng_ctx_value *value)
	59	{
	60	unsigned int uts_ns_inum = 0;
	61
	62	/*
	63	* nsproxy can be NULL when scheduled out of exit.
	64	*
	65	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	66	* precautions should be taken when accessing the current task's
	67	* namespaces, just dereference the pointers.
	68	*/
	69	if (current->nsproxy)
	70	uts_ns_inum = current->nsproxy->uts_ns->lttng_ns_inum;
	71
	72	value->s64 = uts_ns_inum;
	73	}
	74
	75	int lttng_add_uts_ns_to_ctx(struct lttng_ctx **ctx)
	76	{
	77	struct lttng_ctx_field *field;
	78
	79	field = lttng_append_context(ctx);
	80	if (!field)
	81	return -ENOMEM;
82	if (lttng_find_context(*ctx, "uts_ns")) {
83	lttng_remove_context_field(ctx, field);
84	return -EEXIST;
85	}
86	field->event_field.name = "uts_ns";
87	field->event_field.type.atype = atype_integer;
ceabb767 MD	88	field->event_field.type.u.integer.size = sizeof(unsigned int) * CHAR_BIT;
	89	field->event_field.type.u.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT;
	90	field->event_field.type.u.integer.signedness = lttng_is_signed_type(unsigned int);
	91	field->event_field.type.u.integer.reverse_byte_order = 0;
	92	field->event_field.type.u.integer.base = 10;
	93	field->event_field.type.u.integer.encoding = lttng_encode_none;
a6cf40a4 MJ	94	field->get_size = uts_ns_get_size;
	95	field->record = uts_ns_record;
	96	field->get_value = uts_ns_get_value;
	97	lttng_context_update(*ctx);
a6cf40a4 MJ	98	return 0;
	99	}
	100	EXPORT_SYMBOL_GPL(lttng_add_uts_ns_to_ctx);
	101
	102	#endif