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

/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
 *
 * lttng-context-mnt-ns.c
 *
 * LTTng mount 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 <lttng-events.h>
#include <linux/nsproxy.h>
#include <wrapper/ringbuffer/frontend_types.h>
#include <wrapper/vmalloc.h>
#include <wrapper/namespace.h>
#include <lttng-tracer.h>

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

#include <../fs/mount.h>

static
size_t mnt_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 mnt_ns_record(struct lttng_ctx_field *field,
		 struct lib_ring_buffer_ctx *ctx,
		 struct lttng_channel *chan)
{
	unsigned int mnt_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)
		mnt_ns_inum = current->nsproxy->mnt_ns->lttng_ns_inum;

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

static
void mnt_ns_get_value(struct lttng_ctx_field *field,
		struct lttng_probe_ctx *lttng_probe_ctx,
		union lttng_ctx_value *value)
{
	unsigned int mnt_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)
		mnt_ns_inum = current->nsproxy->mnt_ns->lttng_ns_inum;

	value->s64 = mnt_ns_inum;
}

int lttng_add_mnt_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, "mnt_ns")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "mnt_ns";
	field->event_field.type.atype = atype_integer;
	field->event_field.type.u.basic.integer.size = sizeof(unsigned int) * CHAR_BIT;
	field->event_field.type.u.basic.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT;
	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(unsigned int);
	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 = mnt_ns_get_size;
	field->record = mnt_ns_record;
	field->get_value = mnt_ns_get_value;
	lttng_context_update(*ctx);
	wrapper_vmalloc_sync_mappings();
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_mnt_ns_to_ctx);

#endif
Commit	Line	Data
	1	/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
	2	*
	3	* lttng-context-mnt-ns.c
	4	*
	5	* LTTng mount 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 <lttng-events.h>
	16	#include <linux/nsproxy.h>
	17	#include <wrapper/ringbuffer/frontend_types.h>
	18	#include <wrapper/vmalloc.h>
	19	#include <wrapper/namespace.h>
	20	#include <lttng-tracer.h>
	21
	22	#if !defined(LTTNG_MNT_NS_MISSING_HEADER) && \
	23	(LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0))
	24
	25	#include <../fs/mount.h>
	26
	27	static
	28	size_t mnt_ns_get_size(size_t offset)
	29	{
	30	size_t size = 0;
	31
	32	size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int));
	33	size += sizeof(unsigned int);
	34	return size;
	35	}
	36
	37	static
	38	void mnt_ns_record(struct lttng_ctx_field *field,
	39	struct lib_ring_buffer_ctx *ctx,
	40	struct lttng_channel *chan)
	41	{
	42	unsigned int mnt_ns_inum = 0;
	43
	44	/*
	45	* nsproxy can be NULL when scheduled out of exit.
	46	*
	47	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	48	* precautions should be taken when accessing the current task's
	49	* namespaces, just dereference the pointers.
	50	*/
	51	if (current->nsproxy)
	52	mnt_ns_inum = current->nsproxy->mnt_ns->lttng_ns_inum;
	53
	54	lib_ring_buffer_align_ctx(ctx, lttng_alignof(mnt_ns_inum));
	55	chan->ops->event_write(ctx, &mnt_ns_inum, sizeof(mnt_ns_inum));
	56	}
	57
	58	static
	59	void mnt_ns_get_value(struct lttng_ctx_field *field,
	60	struct lttng_probe_ctx *lttng_probe_ctx,
	61	union lttng_ctx_value *value)
	62	{
	63	unsigned int mnt_ns_inum = 0;
	64
	65	/*
	66	* nsproxy can be NULL when scheduled out of exit.
	67	*
	68	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	69	* precautions should be taken when accessing the current task's
	70	* namespaces, just dereference the pointers.
	71	*/
	72	if (current->nsproxy)
	73	mnt_ns_inum = current->nsproxy->mnt_ns->lttng_ns_inum;
	74
	75	value->s64 = mnt_ns_inum;
	76	}
	77
	78	int lttng_add_mnt_ns_to_ctx(struct lttng_ctx **ctx)
	79	{
	80	struct lttng_ctx_field *field;
	81
	82	field = lttng_append_context(ctx);
	83	if (!field)
	84	return -ENOMEM;
	85	if (lttng_find_context(*ctx, "mnt_ns")) {
	86	lttng_remove_context_field(ctx, field);
	87	return -EEXIST;
	88	}
	89	field->event_field.name = "mnt_ns";
	90	field->event_field.type.atype = atype_integer;
	91	field->event_field.type.u.basic.integer.size = sizeof(unsigned int) * CHAR_BIT;
	92	field->event_field.type.u.basic.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT;
	93	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(unsigned int);
	94	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	95	field->event_field.type.u.basic.integer.base = 10;
	96	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	97	field->get_size = mnt_ns_get_size;
	98	field->record = mnt_ns_record;
	99	field->get_value = mnt_ns_get_value;
	100	lttng_context_update(*ctx);
	101	wrapper_vmalloc_sync_mappings();
	102	return 0;
	103	}
	104	EXPORT_SYMBOL_GPL(lttng_add_mnt_ns_to_ctx);
	105
	106	#endif