event-rule: introduce event rule tracepoint
[lttng-tools.git] / src / common / pipe.h
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 */
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