[lttng-tools.git] / src / common / kernel-ctl / kernel-ctl.c

/*
 * Copyright (C) 2011 Julien Desfossez <julien.desfossez@polymtl.ca>
 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#include "lttng/tracker.h"
#define _LGPL_SOURCE
#define __USE_LINUX_IOCTL_DEFS
#include <sys/ioctl.h>
#include <string.h>
#include <common/align.h>
#include <common/macros.h>
#include <common/compat/errno.h>
#include <stdarg.h>
#include <assert.h>
#include <common/time.h>

#include "kernel-ctl.h"
#include "kernel-ioctl.h"

#define LTTNG_IOCTL_CHECK(fildes, request, ...) ({	\
	int ret = ioctl(fildes, request, ##__VA_ARGS__);\
	assert(ret <= 0);				\
	!ret ? 0 : -errno;				\
})

#define LTTNG_IOCTL_NO_CHECK(fildes, request, ...) ({	\
	int ret = ioctl(fildes, request, ##__VA_ARGS__);\
	ret >= 0 ? ret : -errno;			\
})

/*
 * This flag indicates which version of the kernel ABI to use. The old
 * ABI (namespace _old) does not support a 32-bit user-space when the
 * kernel is 64-bit. The old ABI is kept here for compatibility but is
 * deprecated and will be removed eventually.
 */
static int lttng_kernel_use_old_abi = -1;

/*
 * Execute the new or old ioctl depending on the ABI version.
 * If the ABI version is not determined yet (lttng_kernel_use_old_abi = -1),
 * this function tests if the new ABI is available and otherwise fallbacks
 * on the old one.
 * This function takes the fd on which the ioctl must be executed and the old
 * and new request codes.
 * It returns the return value of the ioctl executed.
 */
static inline int compat_ioctl_no_arg(int fd, unsigned long oldname,
		unsigned long newname)
{
	int ret;

	if (lttng_kernel_use_old_abi == -1) {
		ret = LTTNG_IOCTL_NO_CHECK(fd, newname);
		if (!ret) {
			lttng_kernel_use_old_abi = 0;
			goto end;
		}
		lttng_kernel_use_old_abi = 1;
	}
	if (lttng_kernel_use_old_abi) {
		ret = LTTNG_IOCTL_NO_CHECK(fd, oldname);
	} else {
		ret = LTTNG_IOCTL_NO_CHECK(fd, newname);
	}

end:
	return ret;
}

int kernctl_create_session(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION,
			LTTNG_KERNEL_SESSION);
}

/* open the metadata global channel */
int kernctl_open_metadata(int fd, struct lttng_channel_attr *chops)
{
	struct lttng_kernel_channel channel;

	if (lttng_kernel_use_old_abi) {
		struct lttng_kernel_old_channel old_channel;

		memset(&old_channel, 0, sizeof(old_channel));
		old_channel.overwrite = chops->overwrite;
		old_channel.subbuf_size = chops->subbuf_size;
		old_channel.num_subbuf = chops->num_subbuf;
		old_channel.switch_timer_interval = chops->switch_timer_interval;
		old_channel.read_timer_interval = chops->read_timer_interval;
		old_channel.output = chops->output;

		memset(old_channel.padding, 0, sizeof(old_channel.padding));
		/*
		 * The new channel padding is smaller than the old ABI so we use the
		 * new ABI padding size for the memcpy.
		 */
		memcpy(old_channel.padding, chops->padding, sizeof(chops->padding));

		return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_METADATA,
			        &old_channel);
	}

	memset(&channel, 0, sizeof(channel));
	channel.overwrite = chops->overwrite;
	channel.subbuf_size = chops->subbuf_size;
	channel.num_subbuf = chops->num_subbuf;
	channel.switch_timer_interval = chops->switch_timer_interval;
	channel.read_timer_interval = chops->read_timer_interval;
	channel.output = chops->output;
	memcpy(channel.padding, chops->padding, sizeof(chops->padding));

	return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_METADATA, &channel);
}

int kernctl_create_channel(int fd, struct lttng_channel_attr *chops)
{
	struct lttng_kernel_channel channel;

	memset(&channel, 0, sizeof(channel));
	if (lttng_kernel_use_old_abi) {
		struct lttng_kernel_old_channel old_channel;

		old_channel.overwrite = chops->overwrite;
		old_channel.subbuf_size = chops->subbuf_size;
		old_channel.num_subbuf = chops->num_subbuf;
		old_channel.switch_timer_interval = chops->switch_timer_interval;
		old_channel.read_timer_interval = chops->read_timer_interval;
		old_channel.output = chops->output;

		memset(old_channel.padding, 0, sizeof(old_channel.padding));
		/*
		 * The new channel padding is smaller than the old ABI so we use the
		 * new ABI padding size for the memcpy.
		 */
		memcpy(old_channel.padding, chops->padding, sizeof(chops->padding));

		return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_CHANNEL,
			        &old_channel);
	}

	channel.overwrite = chops->overwrite;
	channel.subbuf_size = chops->subbuf_size;
	channel.num_subbuf = chops->num_subbuf;
	channel.switch_timer_interval = chops->switch_timer_interval;
	channel.read_timer_interval = chops->read_timer_interval;
	channel.output = chops->output;
	memcpy(channel.padding, chops->padding, sizeof(chops->padding));

	return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_CHANNEL, &channel);
}

int kernctl_create_session_counter(int session_fd, struct lttng_kernel_counter_conf *counter_conf)
{
	return LTTNG_IOCTL_NO_CHECK(session_fd, LTTNG_KERNEL_COUNTER, counter_conf);
}


int kernctl_syscall_mask(int fd, char **syscall_mask, uint32_t *nr_bits)
{
	struct lttng_kernel_syscall_mask kmask_len, *kmask = NULL;
	size_t array_alloc_len;
	char *new_mask;
	int ret = 0;

	if (!syscall_mask) {
		ret = -1;
		goto end;
	}

	if (!nr_bits) {
		ret = -1;
		goto end;
	}

	kmask_len.len = 0;
	ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SYSCALL_MASK, &kmask_len);
	if (ret) {
		goto end;
	}

	array_alloc_len = ALIGN(kmask_len.len, 8) >> 3;

	kmask = zmalloc(sizeof(*kmask) + array_alloc_len);
	if (!kmask) {
		ret = -1;
		goto end;
	}

	kmask->len = kmask_len.len;
	ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SYSCALL_MASK, kmask);
	if (ret) {
		goto end;
	}

	new_mask = realloc(*syscall_mask, array_alloc_len);
	if (!new_mask) {
		ret = -1;
		goto end;
	}
	memcpy(new_mask, kmask->mask, array_alloc_len);
	*syscall_mask = new_mask;
	*nr_bits = kmask->len;

end:
	free(kmask);
	return ret;
}

int kernctl_track_pid(int fd, int pid)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_TRACK_PID, pid);
}

int kernctl_untrack_pid(int fd, int pid)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_UNTRACK_PID, pid);
}

int kernctl_list_tracker_pids(int fd)
{
	return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS);
}

static enum lttng_kernel_tracker_type get_kernel_tracker_type(
		enum lttng_process_attr process_attr)
{
	switch (process_attr) {
	case LTTNG_PROCESS_ATTR_PROCESS_ID:
		return LTTNG_KERNEL_TRACKER_PID;
	case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
		return LTTNG_KERNEL_TRACKER_VPID;
	case LTTNG_PROCESS_ATTR_USER_ID:
		return LTTNG_KERNEL_TRACKER_UID;
	case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
		return LTTNG_KERNEL_TRACKER_VUID;
	case LTTNG_PROCESS_ATTR_GROUP_ID:
		return LTTNG_KERNEL_TRACKER_GID;
	case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
		return LTTNG_KERNEL_TRACKER_VGID;
	default:
		return LTTNG_KERNEL_TRACKER_UNKNOWN;
	}
}

int kernctl_track_id(int fd, enum lttng_process_attr process_attr, int id)
{
	struct lttng_kernel_tracker_args args;

	args.id = id;
	args.type = get_kernel_tracker_type(process_attr);
	if (args.type == LTTNG_KERNEL_TRACKER_UNKNOWN) {
		errno = EINVAL;
		return -1;
	}
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_TRACK_ID, &args);
}

int kernctl_untrack_id(int fd, enum lttng_process_attr process_attr, int id)
{
	struct lttng_kernel_tracker_args args;

	args.id = id;
	args.type = get_kernel_tracker_type(process_attr);
	if (args.type == LTTNG_KERNEL_TRACKER_UNKNOWN) {
		errno = EINVAL;
		return -1;
	}
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_UNTRACK_ID, &args);
}

int kernctl_list_tracker_ids(int fd, enum lttng_process_attr process_attr)
{
	struct lttng_kernel_tracker_args args;

	args.id = -1;
	args.type = get_kernel_tracker_type(process_attr);
	if (args.type == LTTNG_KERNEL_TRACKER_UNKNOWN) {
		errno = EINVAL;
		return -1;
	}
	return LTTNG_IOCTL_NO_CHECK(
			fd, LTTNG_KERNEL_SESSION_LIST_TRACKER_IDS, &args);
}

int kernctl_session_regenerate_metadata(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_METADATA_REGEN);
}

int kernctl_session_regenerate_statedump(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_STATEDUMP);
}

int kernctl_session_set_name(int fd, const char *name)
{
	int ret;
	struct lttng_kernel_session_name session_name;

	ret = lttng_strncpy(session_name.name, name, sizeof(session_name.name));
	if (ret) {
		goto end;
	}

	ret = LTTNG_IOCTL_CHECK(
			fd, LTTNG_KERNEL_SESSION_SET_NAME, &session_name);
end:
	return ret;
}

int kernctl_session_set_creation_time(int fd, time_t time)
{
	int ret;
	struct lttng_kernel_session_creation_time creation_time;

	ret = time_to_iso8601_str(time, creation_time.iso8601,
			sizeof(creation_time.iso8601));
	if (ret) {
		goto end;
	}

	ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_SET_CREATION_TIME,
			&creation_time);
end:
	return ret;
}

int kernctl_create_stream(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_STREAM,
			LTTNG_KERNEL_STREAM);
}

int kernctl_create_event(int fd, struct lttng_kernel_event *ev)
{
	if (lttng_kernel_use_old_abi) {
		struct lttng_kernel_old_event old_event;

		memset(&old_event, 0, sizeof(old_event));
		memcpy(old_event.name, ev->name, sizeof(old_event.name));
		old_event.instrumentation = ev->instrumentation;
		switch (ev->instrumentation) {
		case LTTNG_KERNEL_KPROBE:
			old_event.u.kprobe.addr = ev->u.kprobe.addr;
			old_event.u.kprobe.offset = ev->u.kprobe.offset;
			memcpy(old_event.u.kprobe.symbol_name,
				ev->u.kprobe.symbol_name,
				sizeof(old_event.u.kprobe.symbol_name));
			break;
		case LTTNG_KERNEL_KRETPROBE:
			old_event.u.kretprobe.addr = ev->u.kretprobe.addr;
			old_event.u.kretprobe.offset = ev->u.kretprobe.offset;
			memcpy(old_event.u.kretprobe.symbol_name,
				ev->u.kretprobe.symbol_name,
				sizeof(old_event.u.kretprobe.symbol_name));
			break;
		case LTTNG_KERNEL_FUNCTION:
			memcpy(old_event.u.ftrace.symbol_name,
					ev->u.ftrace.symbol_name,
					sizeof(old_event.u.ftrace.symbol_name));
			break;
		default:
			break;
		}

		return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_EVENT,
			        &old_event);
	}
	return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_EVENT, ev);
}

int kernctl_add_context(int fd, struct lttng_kernel_context *ctx)
{
	if (lttng_kernel_use_old_abi) {
		struct lttng_kernel_old_context old_ctx;

		memset(&old_ctx, 0, sizeof(old_ctx));
		old_ctx.ctx = ctx->ctx;
		/* only type that uses the union */
		if (ctx->ctx == LTTNG_KERNEL_CONTEXT_PERF_CPU_COUNTER) {
			old_ctx.u.perf_counter.type =
				ctx->u.perf_counter.type;
			old_ctx.u.perf_counter.config =
				ctx->u.perf_counter.config;
			memcpy(old_ctx.u.perf_counter.name,
				ctx->u.perf_counter.name,
				sizeof(old_ctx.u.perf_counter.name));
		}
		return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_OLD_CONTEXT, &old_ctx);
	}
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_CONTEXT, ctx);
}


/* Enable event, channel and session LTTNG_IOCTL_CHECK */
int kernctl_enable(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_ENABLE,
			LTTNG_KERNEL_ENABLE);
}

/* Disable event, channel and session LTTNG_IOCTL_CHECK */
int kernctl_disable(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_DISABLE,
			LTTNG_KERNEL_DISABLE);
}

int kernctl_start_session(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION_START,
			LTTNG_KERNEL_SESSION_START);
}

int kernctl_stop_session(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION_STOP,
			LTTNG_KERNEL_SESSION_STOP);
}

int kernctl_create_event_notifier_group(int fd)
{
	return LTTNG_IOCTL_NO_CHECK(fd,
			LTTNG_KERNEL_EVENT_NOTIFIER_GROUP_CREATE);
}

int kernctl_create_counter_event(int fd, struct lttng_kernel_counter_event *ev)
{
	return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_COUNTER_EVENT, ev);
}

int kernctl_create_event_notifier_group_notification_fd(int group_fd)
{
	return LTTNG_IOCTL_NO_CHECK(group_fd,
			LTTNG_KERNEL_EVENT_NOTIFIER_GROUP_NOTIFICATION_FD);
}

int kernctl_create_event_notifier_group_error_counter(int group_fd,
		struct lttng_kernel_counter_conf *error_counter_conf)
{
	return LTTNG_IOCTL_NO_CHECK(group_fd, LTTNG_KERNEL_COUNTER,
			error_counter_conf);
}

int kernctl_counter_read_value(int counter_fd,
		struct lttng_kernel_counter_read *value)
{
	return LTTNG_IOCTL_NO_CHECK(counter_fd, LTTNG_KERNEL_COUNTER_READ,
			value);
}

int kernctl_counter_get_aggregate_value(int counter_fd,
		struct lttng_kernel_counter_aggregate *value)
{
	return LTTNG_IOCTL_NO_CHECK(counter_fd, LTTNG_KERNEL_COUNTER_AGGREGATE,
			value);
}

int kernctl_counter_clear(int counter_fd,
		struct lttng_kernel_counter_clear *clear)
{
	return LTTNG_IOCTL_NO_CHECK(counter_fd, LTTNG_KERNEL_COUNTER_CLEAR,
			clear);
}

int kernctl_counter_map_descriptor_count(int counter_fd, uint64_t *count)
{
	struct lttng_kernel_counter_map_nr_descriptors nr_desc;
	int ret;

	ret = LTTNG_IOCTL_NO_CHECK(counter_fd,
			LTTNG_KERNEL_COUNTER_MAP_NR_DESCRIPTORS, &nr_desc);
	*count = nr_desc.nr_descriptors;

	return ret;
}

int kernctl_counter_map_descriptor(int counter_fd,
		struct lttng_kernel_counter_map_descriptor *descriptor)
{
	return LTTNG_IOCTL_NO_CHECK(counter_fd,
			LTTNG_KERNEL_COUNTER_MAP_DESCRIPTOR, descriptor);
}

int kernctl_create_event_notifier(int group_fd,
		const struct lttng_kernel_event_notifier *event_notifier)
{
	return LTTNG_IOCTL_NO_CHECK(group_fd,
			LTTNG_KERNEL_EVENT_NOTIFIER_CREATE, event_notifier);
}

int kernctl_capture(int fd, const struct lttng_bytecode *capture)
{
	struct lttng_kernel_capture_bytecode *kb;
	uint32_t len;
	int ret;

	/* Translate bytecode to kernel bytecode */
	kb = zmalloc(sizeof(*kb) + capture->len);
	if (!kb)
		return -ENOMEM;
	kb->len = len = capture->len;
	kb->reloc_offset = capture->reloc_table_offset;
	kb->seqnum = capture->seqnum;
	memcpy(kb->data, capture->data, len);
	ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_CAPTURE, kb);
	free(kb);
	return ret;
}

int kernctl_filter(int fd, const struct lttng_bytecode *filter)
{
	struct lttng_kernel_filter_bytecode *kb;
	uint32_t len;
	int ret;

	/* Translate bytecode to kernel bytecode */
	kb = zmalloc(sizeof(*kb) + filter->len);
	if (!kb)
		return -ENOMEM;
	kb->len = len = filter->len;
	kb->reloc_offset = filter->reloc_table_offset;
	kb->seqnum = filter->seqnum;
	memcpy(kb->data, filter->data, len);
	ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_FILTER, kb);
	free(kb);
	return ret;
}

int kernctl_add_callsite(int fd, struct lttng_kernel_event_callsite *callsite)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_ADD_CALLSITE, callsite);
}

int kernctl_tracepoint_list(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_TRACEPOINT_LIST,
			LTTNG_KERNEL_TRACEPOINT_LIST);
}

int kernctl_syscall_list(int fd)
{
	return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_SYSCALL_LIST);
}

int kernctl_tracer_version(int fd, struct lttng_kernel_tracer_version *v)
{
	int ret;

	if (lttng_kernel_use_old_abi == -1) {
		ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_VERSION, v);
		if (!ret) {
			lttng_kernel_use_old_abi = 0;
			goto end;
		}
		lttng_kernel_use_old_abi = 1;
	}
	if (lttng_kernel_use_old_abi) {
		struct lttng_kernel_old_tracer_version old_v;

		ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_OLD_TRACER_VERSION, &old_v);
		if (ret) {
			goto end;
		}
		v->major = old_v.major;
		v->minor = old_v.minor;
		v->patchlevel = old_v.patchlevel;
	} else {
		ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_VERSION, v);
	}

end:
	return ret;
}

int kernctl_tracer_abi_version(int fd,
		struct lttng_kernel_tracer_abi_version *v)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_ABI_VERSION, v);
}

int kernctl_wait_quiescent(int fd)
{
	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_WAIT_QUIESCENT,
			LTTNG_KERNEL_WAIT_QUIESCENT);
}

int kernctl_buffer_flush(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_FLUSH);
}

int kernctl_buffer_flush_empty(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_FLUSH_EMPTY);
}

int kernctl_buffer_clear(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_CLEAR);
}

int kernctl_get_next_subbuf_metadata_check(int fd, bool *consistent)
{
	return LTTNG_IOCTL_NO_CHECK(fd,
			RING_RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK,
			consistent);
}

/* returns the version of the metadata. */
int kernctl_get_metadata_version(int fd, uint64_t *version)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_METADATA_VERSION, version);
}

int kernctl_metadata_cache_dump(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_METADATA_CACHE_DUMP);
}

/* Buffer operations */

/* For mmap mode, readable without "get" operation */

/* returns the length to mmap. */
int kernctl_get_mmap_len(int fd, unsigned long *len)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MMAP_LEN, len);
}

/* returns the maximum size for sub-buffers. */
int kernctl_get_max_subbuf_size(int fd, unsigned long *len)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MAX_SUBBUF_SIZE, len);
}

/*
 * For mmap mode, operate on the current packet (between get/put or
 * get_next/put_next).
 */

/* returns the offset of the subbuffer belonging to the mmap reader. */
int kernctl_get_mmap_read_offset(int fd, unsigned long *off)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MMAP_READ_OFFSET, off);
}

/* returns the size of the current sub-buffer, without padding (for mmap). */
int kernctl_get_subbuf_size(int fd, unsigned long *len)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_SUBBUF_SIZE, len);
}

/* returns the size of the current sub-buffer, without padding (for mmap). */
int kernctl_get_padded_subbuf_size(int fd, unsigned long *len)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_PADDED_SUBBUF_SIZE, len);
}

/* Get exclusive read access to the next sub-buffer that can be read. */
int kernctl_get_next_subbuf(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_NEXT_SUBBUF);
}


/* Release exclusive sub-buffer access, move consumer forward. */
int kernctl_put_next_subbuf(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_PUT_NEXT_SUBBUF);
}

/* snapshot */

/* Get a snapshot of the current ring buffer producer and consumer positions */
int kernctl_snapshot(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT);
}

/*
 * Get a snapshot of the current ring buffer producer and consumer positions,
 * regardless of whether or not the two positions are contained within the
 * same sub-buffer.
 */
int kernctl_snapshot_sample_positions(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS);
}

/* Get the consumer position (iteration start) */
int kernctl_snapshot_get_consumed(int fd, unsigned long *pos)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_GET_CONSUMED, pos);
}

/* Get the producer position (iteration end) */
int kernctl_snapshot_get_produced(int fd, unsigned long *pos)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_GET_PRODUCED, pos);
}

/* Get exclusive read access to the specified sub-buffer position */
int kernctl_get_subbuf(int fd, unsigned long *len)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_SUBBUF, len);
}

/* Release exclusive sub-buffer access */
int kernctl_put_subbuf(int fd)
{
	return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_PUT_SUBBUF);
}

/* Returns the timestamp begin of the current sub-buffer. */
int kernctl_get_timestamp_begin(int fd, uint64_t *timestamp_begin)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN,
			timestamp_begin);
}

/* Returns the timestamp end of the current sub-buffer. */
int kernctl_get_timestamp_end(int fd, uint64_t *timestamp_end)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_TIMESTAMP_END,
			timestamp_end);
}

/* Returns the number of discarded events in the current sub-buffer. */
int kernctl_get_events_discarded(int fd, uint64_t *events_discarded)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED,
			events_discarded);
}

/* Returns the content size in the current sub-buffer. */
int kernctl_get_content_size(int fd, uint64_t *content_size)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_CONTENT_SIZE,
			content_size);
}

/* Returns the packet size in the current sub-buffer. */
int kernctl_get_packet_size(int fd, uint64_t *packet_size)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_PACKET_SIZE,
		        packet_size);
}

/* Returns the stream id of the current sub-buffer. */
int kernctl_get_stream_id(int fd, uint64_t *stream_id)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_STREAM_ID,
		        stream_id);
}

/* Returns the current timestamp. */
int kernctl_get_current_timestamp(int fd, uint64_t *ts)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP,
			ts);
}

/* Returns the packet sequence number of the current sub-buffer. */
int kernctl_get_sequence_number(int fd, uint64_t *seq)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_SEQ_NUM, seq);
}

/* Returns the stream instance id. */
int kernctl_get_instance_id(int fd, uint64_t *id)
{
	return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_INSTANCE_ID, id);
}