| 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 */ |