channel.h

/*
 * SPDX-FileCopyrightText: 2014 David Goulet <dgoulet@efficios.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */
 
#ifndef LTTNG_CHANNEL_H
#define LTTNG_CHANNEL_H
 
#include <lttng/domain.h>
#include <lttng/event.h>
#include <lttng/lttng-export.h>
 
#include <stdint.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
enum lttng_channel_allocation_policy {
    LTTNG_CHANNEL_ALLOCATION_POLICY_PER_CPU = 0,
 
    LTTNG_CHANNEL_ALLOCATION_POLICY_PER_CHANNEL = 1,
};
 
/*
 * Tracer channel attributes. For both kernel and user-space.
 *
 * The structures should be initialized to zero before use.
 */
#define LTTNG_CHANNEL_ATTR_PADDING1 (LTTNG_SYMBOL_NAME_LEN + 12)
 
struct lttng_channel_attr {
    int overwrite; /* -1: session default, 1: overwrite, 0: discard */
 
    uint64_t subbuf_size; /* bytes, power of 2 */
 
    uint64_t num_subbuf; /* power of 2 */
 
    unsigned int switch_timer_interval; /* usec */
 
    unsigned int read_timer_interval; /* usec */
 
    enum lttng_event_output output; /* splice, mmap */
 
    /* LTTng 2.1 padding limit */
 
    uint64_t tracefile_size; /* bytes */
 
    uint64_t tracefile_count; /* number of tracefiles */
 
    /* LTTng 2.3 padding limit */
 
    unsigned int live_timer_interval; /* usec */
 
    /* LTTng 2.7 padding limit */
    uint32_t align_to_64;
    union {
        uint64_t padding;
        void *ptr;
    } extended;
 
    char padding[LTTNG_CHANNEL_ATTR_PADDING1];
};
 
/*
 * Channel information structure. For both kernel and user-space.
 *
 * The structures should be initialized to zero before use.
 */
#define LTTNG_CHANNEL_PADDING1 16
 
struct lttng_channel {
    char name[LTTNG_SYMBOL_NAME_LEN];
 
    uint32_t enabled;
 
    struct lttng_channel_attr attr;
 
    char padding[LTTNG_CHANNEL_PADDING1];
};
 
LTTNG_EXPORT extern struct lttng_channel *lttng_channel_create(struct lttng_domain *domain);
 
LTTNG_EXPORT extern void lttng_channel_destroy(struct lttng_channel *channel);
 
LTTNG_EXPORT extern int lttng_list_channels(struct lttng_handle *handle,
                        struct lttng_channel **channels);
 
LTTNG_EXPORT extern int lttng_enable_channel(struct lttng_handle *handle,
                         struct lttng_channel *channel);
 
LTTNG_EXPORT extern int lttng_disable_channel(struct lttng_handle *handle,
                          const char *channel_name);
 
LTTNG_EXPORT extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
                            struct lttng_channel_attr *attr);
 
LTTNG_EXPORT extern int lttng_channel_get_discarded_event_count(struct lttng_channel *channel,
                                uint64_t *count);
 
LTTNG_EXPORT extern int lttng_channel_get_lost_packet_count(struct lttng_channel *channel,
                                uint64_t *count);
 
LTTNG_EXPORT extern int
lttng_channel_get_monitor_timer_interval(const struct lttng_channel *channel, uint64_t *period);
 
LTTNG_EXPORT extern int lttng_channel_set_monitor_timer_interval(struct lttng_channel *channel,
                                 uint64_t period);
 
LTTNG_EXPORT extern int lttng_channel_get_blocking_timeout(const struct lttng_channel *channel,
                               int64_t *timeout);
 
LTTNG_EXPORT extern int lttng_channel_set_blocking_timeout(struct lttng_channel *channel,
                               int64_t timeout);
 
LTTNG_EXPORT extern enum lttng_error_code
lttng_channel_get_allocation_policy(const struct lttng_channel *channel,
                    enum lttng_channel_allocation_policy *policy);
 
LTTNG_EXPORT extern enum lttng_error_code
lttng_channel_set_allocation_policy(struct lttng_channel *channel,
                    enum lttng_channel_allocation_policy policy);
 
#ifdef __cplusplus
}
#endif
 
#endif /* LTTNG_CHANNEL_H */