1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <ui/Fence.h>
18
19#define LOG_TAG "Fence"
20#define ATRACE_TAG ATRACE_TAG_GRAPHICS
21//#define LOG_NDEBUG 0
22
23// We would eliminate the non-conforming zero-length array, but we can't since
24// this is effectively included from the Linux kernel
25#pragma clang diagnostic push
26#pragma clang diagnostic ignored "-Wzero-length-array"
27#include <sync/sync.h>
28#pragma clang diagnostic pop
29
30#include <sys/types.h>
31#include <unistd.h>
32#include <utils/Log.h>
33#include <utils/String8.h>
34#include <utils/Trace.h>
35
36namespace android {
37
38const sp<Fence> Fence::NO_FENCE = sp<Fence>(new Fence);
39
40Fence::Fence(int fenceFd) :
41    mFenceFd(fenceFd) {
42}
43
44Fence::Fence(base::unique_fd fenceFd) :
45    mFenceFd(std::move(fenceFd)) {
46}
47
48status_t Fence::wait(int timeout) {
49    ATRACE_CALL();
50    if (mFenceFd == -1) {
51        return NO_ERROR;
52    }
53    int err = sync_wait(mFenceFd, timeout);
54    return err < 0 ? -errno : status_t(NO_ERROR);
55}
56
57status_t Fence::waitForever(const char* logname) {
58    ATRACE_CALL();
59    if (mFenceFd == -1) {
60        return NO_ERROR;
61    }
62    int warningTimeout = 3000;
63    int err = sync_wait(mFenceFd, warningTimeout);
64    if (err < 0 && errno == ETIME) {
65        ALOGE("%s: fence %d didn't signal in %u ms", logname, mFenceFd.get(),
66                warningTimeout);
67        err = sync_wait(mFenceFd, TIMEOUT_NEVER);
68    }
69    return err < 0 ? -errno : status_t(NO_ERROR);
70}
71
72sp<Fence> Fence::merge(const char* name, const sp<Fence>& f1,
73        const sp<Fence>& f2) {
74    ATRACE_CALL();
75    int result;
76    // Merge the two fences.  In the case where one of the fences is not a
77    // valid fence (e.g. NO_FENCE) we merge the one valid fence with itself so
78    // that a new fence with the given name is created.
79    if (f1->isValid() && f2->isValid()) {
80        result = sync_merge(name, f1->mFenceFd, f2->mFenceFd);
81    } else if (f1->isValid()) {
82        result = sync_merge(name, f1->mFenceFd, f1->mFenceFd);
83    } else if (f2->isValid()) {
84        result = sync_merge(name, f2->mFenceFd, f2->mFenceFd);
85    } else {
86        return NO_FENCE;
87    }
88    if (result == -1) {
89        status_t err = -errno;
90        ALOGE("merge: sync_merge(\"%s\", %d, %d) returned an error: %s (%d)",
91                name, f1->mFenceFd.get(), f2->mFenceFd.get(),
92                strerror(-err), err);
93        return NO_FENCE;
94    }
95    return sp<Fence>(new Fence(result));
96}
97
98sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1,
99        const sp<Fence>& f2) {
100    return merge(name.string(), f1, f2);
101}
102
103int Fence::dup() const {
104    return ::dup(mFenceFd);
105}
106
107nsecs_t Fence::getSignalTime() const {
108    if (mFenceFd == -1) {
109        return SIGNAL_TIME_INVALID;
110    }
111
112    struct sync_fence_info_data* finfo = sync_fence_info(mFenceFd);
113    if (finfo == NULL) {
114        ALOGE("sync_fence_info returned NULL for fd %d", mFenceFd.get());
115        return SIGNAL_TIME_INVALID;
116    }
117    if (finfo->status != 1) {
118        sync_fence_info_free(finfo);
119        return SIGNAL_TIME_PENDING;
120    }
121
122    struct sync_pt_info* pinfo = NULL;
123    uint64_t timestamp = 0;
124    while ((pinfo = sync_pt_info(finfo, pinfo)) != NULL) {
125        if (pinfo->timestamp_ns > timestamp) {
126            timestamp = pinfo->timestamp_ns;
127        }
128    }
129    sync_fence_info_free(finfo);
130
131    return nsecs_t(timestamp);
132}
133
134size_t Fence::getFlattenedSize() const {
135    return 4;
136}
137
138size_t Fence::getFdCount() const {
139    return isValid() ? 1 : 0;
140}
141
142status_t Fence::flatten(void*& buffer, size_t& size, int*& fds, size_t& count) const {
143    if (size < getFlattenedSize() || count < getFdCount()) {
144        return NO_MEMORY;
145    }
146    // Cast to uint32_t since the size of a size_t can vary between 32- and
147    // 64-bit processes
148    FlattenableUtils::write(buffer, size, static_cast<uint32_t>(getFdCount()));
149    if (isValid()) {
150        *fds++ = mFenceFd;
151        count--;
152    }
153    return NO_ERROR;
154}
155
156status_t Fence::unflatten(void const*& buffer, size_t& size, int const*& fds, size_t& count) {
157    if (mFenceFd != -1) {
158        // Don't unflatten if we already have a valid fd.
159        return INVALID_OPERATION;
160    }
161
162    if (size < getFlattenedSize()) {
163        return NO_MEMORY;
164    }
165
166    uint32_t numFds;
167    FlattenableUtils::read(buffer, size, numFds);
168
169    if (numFds > 1) {
170        return BAD_VALUE;
171    }
172
173    if (count < numFds) {
174        return NO_MEMORY;
175    }
176
177    if (numFds) {
178        mFenceFd.reset(*fds++);
179        count--;
180    }
181
182    return NO_ERROR;
183}
184
185} // namespace android
186