[lttng-tools.git] / src / common / pipe.h

/*
 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#ifndef LTTNG_PIPE_H
#define LTTNG_PIPE_H

#include <pthread.h>
#include <common/macros.h>
#include <sys/types.h>

enum lttng_pipe_state {
	LTTNG_PIPE_STATE_OPENED = 1,
	LTTNG_PIPE_STATE_CLOSED = 2,
};

struct lttng_pipe {
	/* Read: 0, Write: 1. */
	int fd[2];
	/*
	 * Flags of the pipe once opened. pipe(2) specifies either O_NONBLOCK or
	 * O_CLOEXEC can be used. Flags are set using fcntl(2) call.
	 */
	int flags;

	/*
	 * These states are protected by the operation mutex below.
	 */
	enum lttng_pipe_state r_state;
	enum lttng_pipe_state w_state;

	/* Held for each read(2) operation. */
	pthread_mutex_t read_mutex;
	/* Held for each write(2) operation. */
	pthread_mutex_t write_mutex;
};

/*
 * Return 1 if read side is open else 0.
 */
static inline int lttng_pipe_is_read_open(const struct lttng_pipe *pipe)
{
	return pipe->r_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
}

/*
 * Return 1 if write side is open else 0.
 */
static inline int lttng_pipe_is_write_open(const struct lttng_pipe *pipe)
{
	return pipe->w_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
}

static inline int lttng_pipe_get_readfd(const struct lttng_pipe *pipe)
{
	return pipe->fd[0];
}

static inline int lttng_pipe_get_writefd(const struct lttng_pipe *pipe)
{
	return pipe->fd[1];
}

LTTNG_HIDDEN
struct lttng_pipe *lttng_pipe_open(int flags);
LTTNG_HIDDEN
struct lttng_pipe *lttng_pipe_named_open(const char *path, mode_t mode,
		int flags);
LTTNG_HIDDEN
int lttng_pipe_write_close(struct lttng_pipe *pipe);
LTTNG_HIDDEN
int lttng_pipe_read_close(struct lttng_pipe *pipe);
/* Close both side of pipe. */
LTTNG_HIDDEN
int lttng_pipe_close(struct lttng_pipe *pipe);
LTTNG_HIDDEN
void lttng_pipe_destroy(struct lttng_pipe *pipe);

LTTNG_HIDDEN
ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count);
LTTNG_HIDDEN
ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf,
		size_t count);
/* Returns and releases the read end of the pipe. */
LTTNG_HIDDEN
int lttng_pipe_release_readfd(struct lttng_pipe *pipe);
/* Returns and releases the write end of the pipe. */
LTTNG_HIDDEN
int lttng_pipe_release_writefd(struct lttng_pipe *pipe);

#endif /* LTTNG_PIPE_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
	3	*
	4	* SPDX-License-Identifier: GPL-2.0-only
	5	*
	6	*/
	7
	8	#ifndef LTTNG_PIPE_H
	9	#define LTTNG_PIPE_H
	10
	11	#include <pthread.h>
	12	#include <common/macros.h>
	13	#include <sys/types.h>
	14
	15	enum lttng_pipe_state {
	16	LTTNG_PIPE_STATE_OPENED = 1,
	17	LTTNG_PIPE_STATE_CLOSED = 2,
	18	};
	19
	20	struct lttng_pipe {
	21	/* Read: 0, Write: 1. */
	22	int fd[2];
	23	/*
	24	* Flags of the pipe once opened. pipe(2) specifies either O_NONBLOCK or
	25	* O_CLOEXEC can be used. Flags are set using fcntl(2) call.
	26	*/
	27	int flags;
	28
	29	/*
	30	* These states are protected by the operation mutex below.
	31	*/
	32	enum lttng_pipe_state r_state;
	33	enum lttng_pipe_state w_state;
	34
	35	/* Held for each read(2) operation. */
	36	pthread_mutex_t read_mutex;
	37	/* Held for each write(2) operation. */
	38	pthread_mutex_t write_mutex;
	39	};
	40
	41	/*
	42	* Return 1 if read side is open else 0.
	43	*/
	44	static inline int lttng_pipe_is_read_open(const struct lttng_pipe *pipe)
	45	{
	46	return pipe->r_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
	47	}
	48
	49	/*
	50	* Return 1 if write side is open else 0.
	51	*/
	52	static inline int lttng_pipe_is_write_open(const struct lttng_pipe *pipe)
	53	{
	54	return pipe->w_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
	55	}
	56
	57	static inline int lttng_pipe_get_readfd(const struct lttng_pipe *pipe)
	58	{
	59	return pipe->fd[0];
	60	}
	61
	62	static inline int lttng_pipe_get_writefd(const struct lttng_pipe *pipe)
	63	{
	64	return pipe->fd[1];
	65	}
	66
	67	LTTNG_HIDDEN
	68	struct lttng_pipe *lttng_pipe_open(int flags);
	69	LTTNG_HIDDEN
	70	struct lttng_pipe lttng_pipe_named_open(const char path, mode_t mode,
	71	int flags);
	72	LTTNG_HIDDEN
	73	int lttng_pipe_write_close(struct lttng_pipe *pipe);
	74	LTTNG_HIDDEN
	75	int lttng_pipe_read_close(struct lttng_pipe *pipe);
	76	/* Close both side of pipe. */
	77	LTTNG_HIDDEN
	78	int lttng_pipe_close(struct lttng_pipe *pipe);
	79	LTTNG_HIDDEN
	80	void lttng_pipe_destroy(struct lttng_pipe *pipe);
	81
	82	LTTNG_HIDDEN
	83	ssize_t lttng_pipe_read(struct lttng_pipe pipe, void buf, size_t count);
	84	LTTNG_HIDDEN
	85	ssize_t lttng_pipe_write(struct lttng_pipe pipe, const void buf,
	86	size_t count);
	87	/* Returns and releases the read end of the pipe. */
	88	LTTNG_HIDDEN
	89	int lttng_pipe_release_readfd(struct lttng_pipe *pipe);
	90	/* Returns and releases the write end of the pipe. */
	91	LTTNG_HIDDEN
	92	int lttng_pipe_release_writefd(struct lttng_pipe *pipe);
	93
	94	#endif /* LTTNG_PIPE_H */