Commit | Line | Data |
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9fd92637 DG |
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 | ||
6c1c0768 | 18 | #define _LGPL_SOURCE |
9fd92637 DG |
19 | #include <assert.h> |
20 | #include <fcntl.h> | |
21 | #include <unistd.h> | |
22 | ||
23 | #include <common/common.h> | |
24 | ||
25 | #include "pipe.h" | |
26 | ||
27 | /* | |
28 | * Lock read side of a pipe. | |
29 | */ | |
30 | static void lock_read_side(struct lttng_pipe *pipe) | |
31 | { | |
32 | pthread_mutex_lock(&pipe->read_mutex); | |
33 | } | |
34 | ||
35 | /* | |
36 | * Unlock read side of a pipe. | |
37 | */ | |
38 | static void unlock_read_side(struct lttng_pipe *pipe) | |
39 | { | |
40 | pthread_mutex_unlock(&pipe->read_mutex); | |
41 | } | |
42 | ||
43 | /* | |
44 | * Lock write side of a pipe. | |
45 | */ | |
46 | static void lock_write_side(struct lttng_pipe *pipe) | |
47 | { | |
48 | pthread_mutex_lock(&pipe->write_mutex); | |
49 | } | |
50 | ||
51 | /* | |
52 | * Unlock write side of a pipe. | |
53 | */ | |
54 | static void unlock_write_side(struct lttng_pipe *pipe) | |
55 | { | |
56 | pthread_mutex_unlock(&pipe->write_mutex); | |
57 | } | |
58 | ||
59 | /* | |
60 | * Internal function. Close read side of pipe WITHOUT locking the mutex. | |
61 | * | |
62 | * Return 0 on success else a negative errno from close(2). | |
63 | */ | |
64 | static int _pipe_read_close(struct lttng_pipe *pipe) | |
65 | { | |
66 | int ret, ret_val = 0; | |
67 | ||
68 | assert(pipe); | |
69 | ||
70 | if (!lttng_pipe_is_read_open(pipe)) { | |
71 | goto end; | |
72 | } | |
73 | ||
74 | do { | |
75 | ret = close(pipe->fd[0]); | |
76 | } while (ret < 0 && errno == EINTR); | |
77 | if (ret < 0) { | |
78 | PERROR("close lttng read pipe"); | |
79 | ret_val = -errno; | |
80 | } | |
81 | pipe->r_state = LTTNG_PIPE_STATE_CLOSED; | |
82 | ||
83 | end: | |
84 | return ret_val; | |
85 | } | |
86 | ||
87 | /* | |
88 | * Internal function. Close write side of pipe WITHOUT locking the mutex. | |
89 | * | |
90 | * Return 0 on success else a negative errno from close(2). | |
91 | */ | |
92 | static int _pipe_write_close(struct lttng_pipe *pipe) | |
93 | { | |
94 | int ret, ret_val = 0; | |
95 | ||
96 | assert(pipe); | |
97 | ||
98 | if (!lttng_pipe_is_write_open(pipe)) { | |
99 | goto end; | |
100 | } | |
101 | ||
102 | do { | |
103 | ret = close(pipe->fd[1]); | |
104 | } while (ret < 0 && errno == EINTR); | |
105 | if (ret < 0) { | |
106 | PERROR("close lttng write pipe"); | |
107 | ret_val = -errno; | |
108 | } | |
109 | pipe->w_state = LTTNG_PIPE_STATE_CLOSED; | |
110 | ||
111 | end: | |
112 | return ret_val; | |
113 | } | |
114 | ||
115 | ||
116 | /* | |
117 | * Open a new lttng pipe and set flags using fcntl(). | |
118 | * | |
119 | * Return a newly allocated lttng pipe on success or else NULL. | |
120 | */ | |
a247c6e0 | 121 | LTTNG_HIDDEN |
9fd92637 DG |
122 | struct lttng_pipe *lttng_pipe_open(int flags) |
123 | { | |
124 | int ret; | |
125 | struct lttng_pipe *p; | |
126 | ||
127 | p = zmalloc(sizeof(*p)); | |
128 | if (!p) { | |
129 | PERROR("zmalloc pipe open"); | |
130 | goto error; | |
131 | } | |
132 | ||
133 | ret = pipe(p->fd); | |
134 | if (ret < 0) { | |
135 | PERROR("lttng pipe"); | |
136 | goto error; | |
137 | } | |
138 | ||
139 | if (flags) { | |
140 | int i; | |
141 | ||
142 | for (i = 0; i < 2; i++) { | |
143 | ret = fcntl(p->fd[i], F_SETFD, flags); | |
144 | if (ret < 0) { | |
145 | PERROR("fcntl lttng pipe %d", flags); | |
146 | goto error; | |
147 | } | |
148 | } | |
149 | } | |
150 | ||
151 | pthread_mutex_init(&p->read_mutex, NULL); | |
152 | pthread_mutex_init(&p->write_mutex, NULL); | |
153 | p->r_state = LTTNG_PIPE_STATE_OPENED; | |
154 | p->w_state = LTTNG_PIPE_STATE_OPENED; | |
155 | p->flags = flags; | |
156 | ||
157 | return p; | |
158 | ||
159 | error: | |
160 | lttng_pipe_destroy(p); | |
161 | return NULL; | |
162 | } | |
163 | ||
164 | /* | |
165 | * Close read side of a lttng pipe. | |
166 | * | |
167 | * Return 0 on success else a negative value. | |
168 | */ | |
a247c6e0 | 169 | LTTNG_HIDDEN |
9fd92637 DG |
170 | int lttng_pipe_read_close(struct lttng_pipe *pipe) |
171 | { | |
172 | int ret; | |
173 | ||
174 | assert(pipe); | |
175 | ||
176 | /* Handle read side first. */ | |
177 | lock_read_side(pipe); | |
178 | ret = _pipe_read_close(pipe); | |
179 | unlock_read_side(pipe); | |
180 | ||
181 | return ret; | |
182 | } | |
183 | ||
184 | /* | |
185 | * Close write side of a lttng pipe. | |
186 | * | |
187 | * Return 0 on success else a negative value. | |
188 | */ | |
a247c6e0 | 189 | LTTNG_HIDDEN |
9fd92637 DG |
190 | int lttng_pipe_write_close(struct lttng_pipe *pipe) |
191 | { | |
192 | int ret; | |
193 | ||
194 | assert(pipe); | |
195 | ||
196 | lock_write_side(pipe); | |
197 | ret = _pipe_write_close(pipe); | |
198 | unlock_write_side(pipe); | |
199 | ||
200 | return ret; | |
201 | } | |
202 | ||
203 | /* | |
204 | * Close both read and write side of a lttng pipe. | |
205 | * | |
206 | * Return 0 on success else a negative value. | |
207 | */ | |
a247c6e0 | 208 | LTTNG_HIDDEN |
9fd92637 DG |
209 | int lttng_pipe_close(struct lttng_pipe *pipe) |
210 | { | |
211 | int ret, ret_val = 0; | |
212 | ||
213 | assert(pipe); | |
214 | ||
215 | ret = lttng_pipe_read_close(pipe); | |
216 | if (ret < 0) { | |
217 | ret_val = ret; | |
218 | } | |
219 | ||
220 | ret = lttng_pipe_write_close(pipe); | |
221 | if (ret < 0) { | |
222 | ret_val = ret; | |
223 | } | |
224 | ||
225 | return ret_val; | |
226 | } | |
227 | ||
228 | /* | |
229 | * Close and destroy a lttng pipe object. Finally, pipe is freed. | |
230 | */ | |
a247c6e0 | 231 | LTTNG_HIDDEN |
9fd92637 DG |
232 | void lttng_pipe_destroy(struct lttng_pipe *pipe) |
233 | { | |
234 | int ret; | |
235 | ||
236 | if (!pipe) { | |
237 | return; | |
238 | } | |
239 | ||
240 | /* | |
241 | * Destroy should *never* be called with a locked mutex. These must always | |
242 | * succeed so we unlock them after the close pipe below. | |
243 | */ | |
244 | ret = pthread_mutex_trylock(&pipe->read_mutex); | |
245 | assert(!ret); | |
246 | ret = pthread_mutex_trylock(&pipe->write_mutex); | |
247 | assert(!ret); | |
248 | ||
249 | /* Close pipes WITHOUT trying to lock the pipes. */ | |
250 | (void) _pipe_read_close(pipe); | |
251 | (void) _pipe_write_close(pipe); | |
252 | ||
253 | unlock_read_side(pipe); | |
254 | unlock_write_side(pipe); | |
255 | ||
256 | (void) pthread_mutex_destroy(&pipe->read_mutex); | |
257 | (void) pthread_mutex_destroy(&pipe->write_mutex); | |
258 | ||
259 | free(pipe); | |
260 | } | |
261 | ||
262 | /* | |
263 | * Read on a lttng pipe and put the data in buf of at least size count. | |
264 | * | |
6cd525e8 MD |
265 | * Return "count" on success. Return < count on error. errno can be used |
266 | * to check the actual error. | |
9fd92637 | 267 | */ |
a247c6e0 | 268 | LTTNG_HIDDEN |
9fd92637 DG |
269 | ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count) |
270 | { | |
6cd525e8 | 271 | ssize_t ret; |
9fd92637 DG |
272 | |
273 | assert(pipe); | |
274 | assert(buf); | |
275 | ||
276 | lock_read_side(pipe); | |
9fd92637 | 277 | if (!lttng_pipe_is_read_open(pipe)) { |
6cd525e8 MD |
278 | ret = -1; |
279 | errno = EBADF; | |
9fd92637 DG |
280 | goto error; |
281 | } | |
6cd525e8 | 282 | ret = lttng_read(pipe->fd[0], buf, count); |
9fd92637 DG |
283 | error: |
284 | unlock_read_side(pipe); | |
285 | return ret; | |
286 | } | |
287 | ||
288 | /* | |
289 | * Write on a lttng pipe using the data in buf and size of count. | |
290 | * | |
6cd525e8 MD |
291 | * Return "count" on success. Return < count on error. errno can be used |
292 | * to check the actual error. | |
9fd92637 | 293 | */ |
a247c6e0 | 294 | LTTNG_HIDDEN |
9fd92637 DG |
295 | ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf, |
296 | size_t count) | |
297 | { | |
6cd525e8 | 298 | ssize_t ret; |
9fd92637 DG |
299 | |
300 | assert(pipe); | |
301 | assert(buf); | |
302 | ||
303 | lock_write_side(pipe); | |
9fd92637 | 304 | if (!lttng_pipe_is_write_open(pipe)) { |
6cd525e8 MD |
305 | ret = -1; |
306 | errno = EBADF; | |
9fd92637 DG |
307 | goto error; |
308 | } | |
6cd525e8 | 309 | ret = lttng_write(pipe->fd[1], buf, count); |
9fd92637 DG |
310 | error: |
311 | unlock_write_side(pipe); | |
312 | return ret; | |
313 | } |