1 /*
2 * sync abstraction
3 * Copyright 2015-2016 Collabora Ltd.
4 *
5 * Based on the implementation from the Android Open Source Project,
6 *
7 * Copyright 2012 Google, Inc
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
23 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
24 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
25 * OTHER DEALINGS IN THE SOFTWARE.
26 */
27
28 #ifndef _LIBSYNC_H
29 #define _LIBSYNC_H
30
31 #include <assert.h>
32 #include <errno.h>
33 #include <poll.h>
34 #include <stdbool.h>
35 #include <stdint.h>
36 #include <string.h>
37 #include <sys/ioctl.h>
38 #include <unistd.h>
39 #include <time.h>
40
41 #include "util/detect_os.h"
42
43 #if defined(__cplusplus)
44 extern "C" {
45 #endif
46
47 #if DETECT_OS_ANDROID
48 /* On Android, rely on the system's libsync instead of rolling our own
49 * sync_wait() and sync_merge(). This gives us compatibility with pre-4.7
50 * Android kernels.
51 */
52 #include <android/sync.h>
53
54 /**
55 * Check if the fd represents a valid fence-fd.
56 *
57 * The android variant of this debug helper is implemented on top of the
58 * system's libsync for compatibility with pre-4.7 android kernels.
59 */
60 static inline bool
sync_valid_fd(int fd)61 sync_valid_fd(int fd)
62 {
63 /* sync_file_info() only available in SDK 26. */
64 #if ANDROID_API_LEVEL >= 26
65 struct sync_file_info *info = sync_file_info(fd);
66 if (!info)
67 return false;
68 sync_file_info_free(info);
69 #endif
70 return true;
71 }
72 #else
73
74 #ifndef SYNC_IOC_MERGE
75 /* duplicated from linux/sync_file.h to avoid build-time dependency
76 * on new (v4.7) kernel headers. Once distro's are mostly using
77 * something newer than v4.7 drop this and #include <linux/sync_file.h>
78 * instead.
79 */
80 struct sync_merge_data {
81 char name[32];
82 int32_t fd2;
83 int32_t fence;
84 uint32_t flags;
85 uint32_t pad;
86 };
87
88 struct sync_file_info {
89 char name[32];
90 int32_t status;
91 uint32_t flags;
92 uint32_t num_fences;
93 uint32_t pad;
94
95 uint64_t sync_fence_info;
96 };
97
98 #define SYNC_IOC_MAGIC '>'
99 #define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data)
100 #define SYNC_IOC_FILE_INFO _IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)
101 #endif
102
103
104 static inline int sync_wait(int fd, int timeout)
105 {
106 struct pollfd fds = {0};
107 int ret;
108 struct timespec poll_start, poll_end;
109
110 fds.fd = fd;
111 fds.events = POLLIN;
112
113 do {
114 clock_gettime(CLOCK_MONOTONIC, &poll_start);
115 ret = poll(&fds, 1, timeout);
116 clock_gettime(CLOCK_MONOTONIC, &poll_end);
117 if (ret > 0) {
118 if (fds.revents & (POLLERR | POLLNVAL)) {
119 errno = EINVAL;
120 return -1;
121 }
122 return 0;
123 } else if (ret == 0) {
124 errno = ETIME;
125 return -1;
126 }
127 timeout -= (poll_end.tv_sec - poll_start.tv_sec) * 1000 +
128 (poll_end.tv_nsec - poll_end.tv_nsec) / 1000000;
129 } while (ret == -1 && (errno == EINTR || errno == EAGAIN));
130
131 return ret;
132 }
133
134 static inline int sync_merge(const char *name, int fd1, int fd2)
135 {
136 struct sync_merge_data data = {{0}};
137 int ret;
138
139 data.fd2 = fd2;
140 strncpy(data.name, name, sizeof(data.name));
141
142 do {
143 ret = ioctl(fd1, SYNC_IOC_MERGE, &data);
144 } while (ret == -1 && (errno == EINTR || errno == EAGAIN));
145
146 if (ret < 0)
147 return ret;
148
149 return data.fence;
150 }
151
152 /**
153 * Check if the fd represents a valid fence-fd.
154 */
155 static inline bool
156 sync_valid_fd(int fd)
157 {
158 struct sync_file_info info = {{0}};
159 return ioctl(fd, SYNC_IOC_FILE_INFO, &info) >= 0;
160 }
161
162 #endif /* DETECT_OS_ANDROID */
163
164 /* accumulate fd2 into fd1. If *fd1 is not a valid fd then dup fd2,
165 * otherwise sync_merge() and close the old *fd1. This can be used
166 * to implement the pattern:
167 *
168 * init()
169 * {
170 * batch.fence_fd = -1;
171 * }
172 *
173 * // does *NOT* take ownership of fd
174 * server_sync(int fd)
175 * {
176 * if (sync_accumulate("foo", &batch.fence_fd, fd)) {
177 * ... error ...
178 * }
179 * }
180 */
sync_accumulate(const char * name,int * fd1,int fd2)181 static inline int sync_accumulate(const char *name, int *fd1, int fd2)
182 {
183 int ret;
184
185 assert(fd2 >= 0);
186
187 if (*fd1 < 0) {
188 *fd1 = dup(fd2);
189 return 0;
190 }
191
192 ret = sync_merge(name, *fd1, fd2);
193 if (ret < 0) {
194 /* leave *fd1 as it is */
195 return ret;
196 }
197
198 close(*fd1);
199 *fd1 = ret;
200
201 return 0;
202 }
203
204 /* Helper macro to complain if fd is non-negative and not a valid fence fd.
205 * Sprinkle this around to help catch fd lifetime issues.
206 */
207 #ifdef DEBUG
208 # include "util/log.h"
209 # define validate_fence_fd(fd) do { \
210 if (((fd) >= 0) && !sync_valid_fd(fd)) \
211 mesa_loge("%s:%d: invalid fence fd: %d", __func__, __LINE__, (fd)); \
212 } while (0)
213 #else
214 # define validate_fence_fd(fd) do {} while (0)
215 #endif
216
217 #if defined(__cplusplus)
218 }
219 #endif
220
221 #endif
222