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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() :
     41     mFenceFd(-1) {
     42 }
     43 
     44 Fence::Fence(int fenceFd) :
     45     mFenceFd(fenceFd) {
     46 }
     47 
     48 Fence::~Fence() {
     49     if (mFenceFd != -1) {
     50         close(mFenceFd);
     51     }
     52 }
     53 
     54 status_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 
     63 status_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 
     78 sp<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 
    104 sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1,
    105         const sp<Fence>& f2) {
    106     return merge(name.string(), f1, f2);
    107 }
    108 
    109 int Fence::dup() const {
    110     return ::dup(mFenceFd);
    111 }
    112 
    113 nsecs_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 
    140 size_t Fence::getFlattenedSize() const {
    141     return 4;
    142 }
    143 
    144 size_t Fence::getFdCount() const {
    145     return isValid() ? 1 : 0;
    146 }
    147 
    148 status_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 
    162 status_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