[lttng-modules.git] / lttng-context-hostname.c

/*
 * lttng-context-hostname.c
 *
 * LTTng hostname 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/utsname.h>
#include "lttng-events.h"
#include "wrapper/ringbuffer/frontend_types.h"
#include "wrapper/vmalloc.h"
#include "lttng-tracer.h"

#define LTTNG_HOSTNAME_CTX_LEN	(__NEW_UTS_LEN + 1)

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

	size += LTTNG_HOSTNAME_CTX_LEN;
	return size;
}

static
void hostname_record(struct lttng_ctx_field *field,
		 struct lib_ring_buffer_ctx *ctx,
		 struct lttng_channel *chan)
{
	struct nsproxy *nsproxy;
	struct uts_namespace *ns;
	char *hostname;

	rcu_read_lock();
	nsproxy = task_nsproxy(current);
	if (nsproxy) {
		ns = nsproxy->uts_ns;
		hostname = ns->name.nodename;
		chan->ops->event_write(ctx, hostname,
				LTTNG_HOSTNAME_CTX_LEN);
	} else {
		chan->ops->event_memset(ctx, 0,
				LTTNG_HOSTNAME_CTX_LEN);
	}
	rcu_read_unlock();
}

int lttng_add_hostname_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, "hostname")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "hostname";
	field->event_field.type.atype = atype_array;
	field->event_field.type.u.array.elem_type.atype = atype_integer;
	field->event_field.type.u.array.elem_type.u.basic.integer.size = sizeof(char) * CHAR_BIT;
	field->event_field.type.u.array.elem_type.u.basic.integer.alignment = lttng_alignof(char) * CHAR_BIT;
	field->event_field.type.u.array.elem_type.u.basic.integer.signedness = is_signed_type(char);
	field->event_field.type.u.array.elem_type.u.basic.integer.reverse_byte_order = 0;
	field->event_field.type.u.array.elem_type.u.basic.integer.base = 10;
	field->event_field.type.u.array.elem_type.u.basic.integer.encoding = lttng_encode_UTF8;
	field->event_field.type.u.array.length = LTTNG_HOSTNAME_CTX_LEN;

	field->get_size = hostname_get_size;
	field->record = hostname_record;
	wrapper_vmalloc_sync_all();
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_hostname_to_ctx);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support");
Commit	Line	Data
975da2c0 JD	1	/*
	2	* lttng-context-hostname.c
	3	*
	4	* LTTng hostname 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/utsname.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	#define LTTNG_HOSTNAME_CTX_LEN (__NEW_UTS_LEN + 1)
	33
	34	static
	35	size_t hostname_get_size(size_t offset)
	36	{
	37	size_t size = 0;
	38
	39	size += LTTNG_HOSTNAME_CTX_LEN;
	40	return size;
	41	}
	42
	43	static
	44	void hostname_record(struct lttng_ctx_field *field,
	45	struct lib_ring_buffer_ctx *ctx,
	46	struct lttng_channel *chan)
	47	{
	48	struct nsproxy *nsproxy;
	49	struct uts_namespace *ns;
	50	char *hostname;
	51
	52	rcu_read_lock();
	53	nsproxy = task_nsproxy(current);
	54	if (nsproxy) {
	55	ns = nsproxy->uts_ns;
	56	hostname = ns->name.nodename;
	57	chan->ops->event_write(ctx, hostname,
	58	LTTNG_HOSTNAME_CTX_LEN);
	59	} else {
	60	chan->ops->event_memset(ctx, 0,
	61	LTTNG_HOSTNAME_CTX_LEN);
	62	}
	63	rcu_read_unlock();
	64	}
65
66	int lttng_add_hostname_to_ctx(struct lttng_ctx **ctx)
67	{
68	struct lttng_ctx_field *field;
69
70	field = lttng_append_context(ctx);
71	if (!field)
72	return -ENOMEM;
73	if (lttng_find_context(*ctx, "hostname")) {
74	lttng_remove_context_field(ctx, field);
75	return -EEXIST;
76	}
77	field->event_field.name = "hostname";
78	field->event_field.type.atype = atype_array;
79	field->event_field.type.u.array.elem_type.atype = atype_integer;
80	field->event_field.type.u.array.elem_type.u.basic.integer.size = sizeof(char) * CHAR_BIT;
81	field->event_field.type.u.array.elem_type.u.basic.integer.alignment = lttng_alignof(char) * CHAR_BIT;
82	field->event_field.type.u.array.elem_type.u.basic.integer.signedness = is_signed_type(char);
83	field->event_field.type.u.array.elem_type.u.basic.integer.reverse_byte_order = 0;
84	field->event_field.type.u.array.elem_type.u.basic.integer.base = 10;
85	field->event_field.type.u.array.elem_type.u.basic.integer.encoding = lttng_encode_UTF8;
86	field->event_field.type.u.array.length = LTTNG_HOSTNAME_CTX_LEN;
87
88	field->get_size = hostname_get_size;
89	field->record = hostname_record;
90	wrapper_vmalloc_sync_all();
91	return 0;
92	}
93	EXPORT_SYMBOL_GPL(lttng_add_hostname_to_ctx);
94
95	MODULE_LICENSE("GPL and additional rights");
96	MODULE_AUTHOR("Mathieu Desnoyers");
97	MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support");