Use case-scope error labels handling LTTNG_CONSUMER_ROTATE_CHANNEL
[lttng-tools.git] / src / common / pipe.h
1 /*
2 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License, version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 51
15 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18 #ifndef LTTNG_PIPE_H
19 #define LTTNG_PIPE_H
20
21 #include <pthread.h>
22 #include <common/macros.h>
23 #include <sys/types.h>
24
25 enum lttng_pipe_state {
26 LTTNG_PIPE_STATE_OPENED = 1,
27 LTTNG_PIPE_STATE_CLOSED = 2,
28 };
29
30 struct lttng_pipe {
31 /* Read: 0, Write: 1. */
32 int fd[2];
33 /*
34 * Flags of the pipe once opened. pipe(2) specifies either O_NONBLOCK or
35 * O_CLOEXEC can be used. Flags are set using fcntl(2) call.
36 */
37 int flags;
38
39 /*
40 * These states are protected by the operation mutex below.
41 */
42 enum lttng_pipe_state r_state;
43 enum lttng_pipe_state w_state;
44
45 /* Held for each read(2) operation. */
46 pthread_mutex_t read_mutex;
47 /* Held for each write(2) operation. */
48 pthread_mutex_t write_mutex;
49 };
50
51 /*
52 * Return 1 if read side is open else 0.
53 */
54 static inline int lttng_pipe_is_read_open(const struct lttng_pipe *pipe)
55 {
56 return pipe->r_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
57 }
58
59 /*
60 * Return 1 if write side is open else 0.
61 */
62 static inline int lttng_pipe_is_write_open(const struct lttng_pipe *pipe)
63 {
64 return pipe->w_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
65 }
66
67 static inline int lttng_pipe_get_readfd(const struct lttng_pipe *pipe)
68 {
69 return pipe->fd[0];
70 }
71
72 static inline int lttng_pipe_get_writefd(const struct lttng_pipe *pipe)
73 {
74 return pipe->fd[1];
75 }
76
77 LTTNG_HIDDEN
78 struct lttng_pipe *lttng_pipe_open(int flags);
79 LTTNG_HIDDEN
80 struct lttng_pipe *lttng_pipe_named_open(const char *path, mode_t mode,
81 int flags);
82 LTTNG_HIDDEN
83 int lttng_pipe_write_close(struct lttng_pipe *pipe);
84 LTTNG_HIDDEN
85 int lttng_pipe_read_close(struct lttng_pipe *pipe);
86 /* Close both side of pipe. */
87 LTTNG_HIDDEN
88 int lttng_pipe_close(struct lttng_pipe *pipe);
89 LTTNG_HIDDEN
90 void lttng_pipe_destroy(struct lttng_pipe *pipe);
91
92 LTTNG_HIDDEN
93 ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count);
94 LTTNG_HIDDEN
95 ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf,
96 size_t count);
97 /* Returns and releases the read end of the pipe. */
98 LTTNG_HIDDEN
99 int lttng_pipe_release_readfd(struct lttng_pipe *pipe);
100 /* Returns and releases the write end of the pipe. */
101 LTTNG_HIDDEN
102 int lttng_pipe_release_writefd(struct lttng_pipe *pipe);
103
104 #endif /* LTTNG_PIPE_H */
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