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() :
41    mFenceFd(-1) {
42}
43
44Fence::Fence(int fenceFd) :
45    mFenceFd(fenceFd) {
46}
47
48Fence::~Fence() {
49    if (mFenceFd != -1) {
50        close(mFenceFd);
51    }
52}
53
54status_t Fence::wait(int timeout) {
55    ATRACE_CALL();
56    if (mFenceFd == -1) {
57        return NO_ERROR;
58    }
59    int err = sync_wait(mFenceFd, timeout);
60    return err < 0 ? -errno : status_t(NO_ERROR);
61}
62
63status_t Fence::waitForever(const char* logname) {
64    ATRACE_CALL();
65    if (mFenceFd == -1) {
66        return NO_ERROR;
67    }
68    int warningTimeout = 3000;
69    int err = sync_wait(mFenceFd, warningTimeout);
70    if (err < 0 && errno == ETIME) {
71        ALOGE("%s: fence %d didn't signal in %u ms", logname, mFenceFd,
72                warningTimeout);
73        err = sync_wait(mFenceFd, TIMEOUT_NEVER);
74    }
75    return err < 0 ? -errno : status_t(NO_ERROR);
76}
77
78sp<Fence> Fence::merge(const char* name, const sp<Fence>& f1,
79        const sp<Fence>& f2) {
80    ATRACE_CALL();
81    int result;
82    // Merge the two fences.  In the case where one of the fences is not a
83    // valid fence (e.g. NO_FENCE) we merge the one valid fence with itself so
84    // that a new fence with the given name is created.
85    if (f1->isValid() && f2->isValid()) {
86        result = sync_merge(name, f1->mFenceFd, f2->mFenceFd);
87    } else if (f1->isValid()) {
88        result = sync_merge(name, f1->mFenceFd, f1->mFenceFd);
89    } else if (f2->isValid()) {
90        result = sync_merge(name, f2->mFenceFd, f2->mFenceFd);
91    } else {
92        return NO_FENCE;
93    }
94    if (result == -1) {
95        status_t err = -errno;
96        ALOGE("merge: sync_merge(\"%s\", %d, %d) returned an error: %s (%d)",
97                name, f1->mFenceFd, f2->mFenceFd,
98                strerror(-err), err);
99        return NO_FENCE;
100    }
101    return sp<Fence>(new Fence(result));
102}
103
104sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1,
105        const sp<Fence>& f2) {
106    return merge(name.string(), f1, f2);
107}
108
109int Fence::dup() const {
110    return ::dup(mFenceFd);
111}
112
113nsecs_t Fence::getSignalTime() const {
114    if (mFenceFd == -1) {
115        return SIGNAL_TIME_INVALID;
116    }
117
118    struct sync_fence_info_data* finfo = sync_fence_info(mFenceFd);
119    if (finfo == NULL) {
120        ALOGE("sync_fence_info returned NULL for fd %d", mFenceFd);
121        return SIGNAL_TIME_INVALID;
122    }
123    if (finfo->status != 1) {
124        sync_fence_info_free(finfo);
125        return SIGNAL_TIME_PENDING;
126    }
127
128    struct sync_pt_info* pinfo = NULL;
129    uint64_t timestamp = 0;
130    while ((pinfo = sync_pt_info(finfo, pinfo)) != NULL) {
131        if (pinfo->timestamp_ns > timestamp) {
132            timestamp = pinfo->timestamp_ns;
133        }
134    }
135    sync_fence_info_free(finfo);
136
137    return nsecs_t(timestamp);
138}
139
140size_t Fence::getFlattenedSize() const {
141    return 4;
142}
143
144size_t Fence::getFdCount() const {
145    return isValid() ? 1 : 0;
146}
147
148status_t Fence::flatten(void*& buffer, size_t& size, int*& fds, size_t& count) const {
149    if (size < getFlattenedSize() || count < getFdCount()) {
150        return NO_MEMORY;
151    }
152    // Cast to uint32_t since the size of a size_t can vary between 32- and
153    // 64-bit processes
154    FlattenableUtils::write(buffer, size, static_cast<uint32_t>(getFdCount()));
155    if (isValid()) {
156        *fds++ = mFenceFd;
157        count--;
158    }
159    return NO_ERROR;
160}
161
162status_t Fence::unflatten(void const*& buffer, size_t& size, int const*& fds, size_t& count) {
163    if (mFenceFd != -1) {
164        // Don't unflatten if we already have a valid fd.
165        return INVALID_OPERATION;
166    }
167
168    if (size < getFlattenedSize()) {
169        return NO_MEMORY;
170    }
171
172    uint32_t numFds;
173    FlattenableUtils::read(buffer, size, numFds);
174
175    if (numFds > 1) {
176        return BAD_VALUE;
177    }
178
179    if (count < numFds) {
180        return NO_MEMORY;
181    }
182
183    if (numFds) {
184        mFenceFd = *fds++;
185        count--;
186    }
187
188    return NO_ERROR;
189}
190
191} // namespace android
192