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Commit d6bca103 authored by Steven Moreland's avatar Steven Moreland
Browse files

libbinder: RPC remove isTriggeredPolled 

We can get this information in-process, so we can avoid the syscall (and
due to the way it is implemented, we also don't need locking).

Bug: 182940634
Test: binderRpcTest
Change-Id: I3a4f683f71f54972509e071f5dd349e15de54b08
parent 5252e756

libs/binder/FdTrigger.cpp

+0 −15
Original line number Diff line number Diff line
@@ -59,19 +59,4 @@ status_t FdTrigger::triggerablePoll(base::borrowed_fd fd, int16_t event) { 
    }

}



android::base::Result<bool> FdTrigger::isTriggeredPolled() {

    pollfd pfd{.fd = mRead.get(), .events = 0, .revents = 0};

    int ret = TEMP_FAILURE_RETRY(poll(&pfd, 1, 0));

    if (ret < 0) {

        return android::base::ErrnoError() << "FdTrigger::isTriggeredPolled: Error in poll()";

    }

    if (ret == 0) {

        return false;

    }

    if (pfd.revents & POLLHUP) {

        return true;

    }

    return android::base::Error() << "FdTrigger::isTriggeredPolled: poll() returns " << pfd.revents;

}



} // namespace android

libs/binder/FdTrigger.h

+5 −11
Original line number Diff line number Diff line
@@ -35,7 +35,11 @@ public: 
    void trigger();



    /**

     * Check whether this has been triggered by checking the write end.

     * Check whether this has been triggered by checking the write end. Note:

     * this has no internal locking, and it is inherently racey, but this is

     * okay, because if we accidentally return false when a trigger has already

     * happened, we can imagine that instead, the scheduler actually executed

     * the code which is polling isTriggered earlier.

     */

    [[nodiscard]] bool isTriggered();
@@ -50,16 +54,6 @@ public: 
     */

    [[nodiscard]] status_t triggerablePoll(base::borrowed_fd fd, int16_t event);



    /**

     * Check whether this has been triggered by poll()ing the read end.

     *

     * Return:

     *   true - triggered

     *   false - not triggered

     *   error - error when polling

     */

    [[nodiscard]] android::base::Result<bool> isTriggeredPolled();



private:

    base::unique_fd mWrite;

    base::unique_fd mRead;

libs/binder/RpcTransportTls.cpp

+2 −13
Original line number Diff line number Diff line
@@ -319,8 +319,6 @@ public: 
private:

    android::base::unique_fd mSocket;

    Ssl mSsl;



    static status_t isTriggered(FdTrigger* fdTrigger);

};



// Error code is errno.
@@ -341,15 +339,6 @@ Result<size_t> RpcTransportTls::peek(void* buf, size_t size) { 
    return ret;

}



status_t RpcTransportTls::isTriggered(FdTrigger* fdTrigger) {

    auto ret = fdTrigger->isTriggeredPolled();

    if (!ret.ok()) {

        ALOGE("%s: %s", __PRETTY_FUNCTION__, ret.error().message().c_str());

        return ret.error().code() == 0 ? UNKNOWN_ERROR : -ret.error().code();

    }

    return *ret ? -ECANCELED : OK;

}



status_t RpcTransportTls::interruptableWriteFully(FdTrigger* fdTrigger, const void* data,

                                                  size_t size) {

    auto buffer = reinterpret_cast<const uint8_t*>(data);
@@ -359,7 +348,7 @@ status_t RpcTransportTls::interruptableWriteFully(FdTrigger* fdTrigger, const vo 


    // Before doing any I/O, check trigger once. This ensures the trigger is checked at least

    // once. The trigger is also checked via triggerablePoll() after every SSL_write().

    if (status_t status = isTriggered(fdTrigger); status != OK) return status;

    if (fdTrigger->isTriggered()) return -ECANCELED;



    while (buffer < end) {

        size_t todo = std::min<size_t>(end - buffer, std::numeric_limits<int>::max());
@@ -390,7 +379,7 @@ status_t RpcTransportTls::interruptableReadFully(FdTrigger* fdTrigger, void* dat 


    // Before doing any I/O, check trigger once. This ensures the trigger is checked at least

    // once. The trigger is also checked via triggerablePoll() after every SSL_write().

    if (status_t status = isTriggered(fdTrigger); status != OK) return status;

    if (fdTrigger->isTriggered()) return -ECANCELED;



    while (buffer < end) {

        size_t todo = std::min<size_t>(end - buffer, std::numeric_limits<int>::max());