session.h

/*
 * SPDX-FileCopyrightText: 2014 David Goulet <dgoulet@efficios.com>
 * SPDX-FileCopyrightText: 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */
 
#ifndef LTTNG_SESSION_H
#define LTTNG_SESSION_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <lttng/lttng-export.h>
 
#include <lttng/constant.h>
 
struct lttng_handle;
struct lttng_session_descriptor;
struct lttng_destruction_handle;
 
#define LTTNG_SESSION_PADDING1 8
 
enum lttng_get_session_shm_path_status {
    LTTNG_GET_SESSION_SHM_PATH_STATUS_OK = 0,
 
    LTTNG_GET_SESSION_SHM_PATH_STATUS_UNSET = 1,
 
    LTTNG_GET_SESSION_SHM_PATH_STATUS_INVALID_PARAMETER = -1,
};
 
struct lttng_session {
    char name[LTTNG_NAME_MAX];
 
    char path[PATH_MAX];
 
    uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
 
    uint32_t snapshot_mode;
 
    unsigned int live_timer_interval; /* usec */
 
    /*
     * End of public attributes.
     * The remaining fields are used to deal with ABI management concerns.
     */
 
    /*
     * 32-bit architectures are already naturally aligned on 4 bytes after
     * 'live_timer_interval'. However, the offset does not result in a
     * natural alignment on 64-bit architectures. Adding 4 bytes of
     * padding here results in an aligned offset after 'alignement_padding'
     * for both bitnesses.
     *
     * This was added since not all compilers appear to align unions in the
     * same way. Some (e.g. MSVC) do not seem to impose an alignement
     * constraint while others (e.g. gcc, clang, icc) seem to align it to
     * ensure 'ptr' is naturally aligned.
     */
    char alignment_padding[4];
    union {
        /*
         * Ensure the 'extended' union has the same size for both
         * 32-bit and 64-bit builds.
         */
        char padding[LTTNG_SESSION_PADDING1];
        void *ptr;
    } extended;
};
 
LTTNG_EXPORT extern enum lttng_error_code
lttng_create_session_ext(struct lttng_session_descriptor *session_descriptor);
 
LTTNG_EXPORT extern int lttng_create_session(const char *session_name, const char *output_url);
 
LTTNG_EXPORT extern int lttng_create_session_snapshot(const char *session_name,
                              const char *output_url);
 
LTTNG_EXPORT extern int lttng_create_session_live(const char *session_name,
                          const char *output_url,
                          unsigned int live_timer_period);
 
LTTNG_EXPORT extern int lttng_destroy_session(const char *session_name);
 
LTTNG_EXPORT extern int lttng_destroy_session_no_wait(const char *session_name);
 
LTTNG_EXPORT extern enum lttng_error_code
lttng_destroy_session_ext(const char *session_name, struct lttng_destruction_handle **handle);
 
LTTNG_EXPORT extern int lttng_list_sessions(struct lttng_session **sessions);
 
LTTNG_EXPORT extern enum lttng_error_code
lttng_session_get_creation_time(const struct lttng_session *session, uint64_t *creation_timestamp);
 
LTTNG_EXPORT extern int lttng_set_session_shm_path(const char *session_name, const char *shm_dir);
 
LTTNG_EXPORT extern enum lttng_get_session_shm_path_status
lttng_get_session_shm_path_override(const struct lttng_session *session, const char **shm_dir);
 
 
#ifdef __cplusplus
}
#endif
 
#endif /* LTTNG_SESSION_H */