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      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 
     36 namespace android {
     37 
     38 const sp<Fence> Fence::NO_FENCE = sp<Fence>(new Fence);
     39 
     40 Fence::Fence(int fenceFd) :
     41     mFenceFd(fenceFd) {
     42 }
     43 
     44 Fence::Fence(base::unique_fd fenceFd) :
     45     mFenceFd(std::move(fenceFd)) {
     46 }
     47 
     48 status_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 
     57 status_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 
     72 sp<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 
     98 sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1,
     99         const sp<Fence>& f2) {
    100     return merge(name.string(), f1, f2);
    101 }
    102 
    103 int Fence::dup() const {
    104     return ::dup(mFenceFd);
    105 }
    106 
    107 nsecs_t Fence::getSignalTime() const {
    108     if (mFenceFd == -1) {
    109         return SIGNAL_TIME_INVALID;
    110     }
    111 
    112     struct sync_file_info* finfo = sync_file_info(mFenceFd);
    113     if (finfo == nullptr) {
    114         ALOGE("sync_file_info returned NULL for fd %d", mFenceFd.get());
    115         return SIGNAL_TIME_INVALID;
    116     }
    117     if (finfo->status != 1) {
    118         sync_file_info_free(finfo);
    119         return SIGNAL_TIME_PENDING;
    120     }
    121 
    122     uint64_t timestamp = 0;
    123     struct sync_fence_info* pinfo = sync_get_fence_info(finfo);
    124     for (size_t i = 0; i < finfo->num_fences; i++) {
    125         if (pinfo[i].timestamp_ns > timestamp) {
    126             timestamp = pinfo[i].timestamp_ns;
    127         }
    128     }
    129 
    130     sync_file_info_free(finfo);
    131     return nsecs_t(timestamp);
    132 }
    133 
    134 size_t Fence::getFlattenedSize() const {
    135     return 4;
    136 }
    137 
    138 size_t Fence::getFdCount() const {
    139     return isValid() ? 1 : 0;
    140 }
    141 
    142 status_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 
    156 status_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