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Commit 5df2db7c authored by TreeHugger Robot's avatar TreeHugger Robot Committed by Automerger Merge Worker
Browse files

Merge "incidentd: fix race in waitpid_with_timeout" into tm-dev am: 83a91c85 

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16993689

Change-Id: Ic557ec7259154d4b0942a3f4fb5102e5e22cc5de
parents 3e1c48f0 83a91c85

cmds/incidentd/src/incidentd_util.cpp

+27 −12
Original line number Diff line number Diff line
@@ -184,11 +184,26 @@ static bool waitpid_with_timeout(pid_t pid, int timeout_ms, int* status) { 
    sigemptyset(&child_mask);

    sigaddset(&child_mask, SIGCHLD);



    // block SIGCHLD before we check if a process has exited

    if (sigprocmask(SIG_BLOCK, &child_mask, &old_mask) == -1) {

        ALOGW("sigprocmask failed: %s", strerror(errno));

        ALOGW("*** sigprocmask failed: %s\n", strerror(errno));

        return false;

    }



    // if the child has exited already, handle and reset signals before leaving

    pid_t child_pid = waitpid(pid, status, WNOHANG);

    if (child_pid != pid) {

        if (child_pid > 0) {

            ALOGW("*** Waiting for pid %d, got pid %d instead\n", pid, child_pid);

            sigprocmask(SIG_SETMASK, &old_mask, nullptr);

            return false;

        }

    } else {

        sigprocmask(SIG_SETMASK, &old_mask, nullptr);

        return true;

    }



    // wait for a SIGCHLD

    timespec ts;

    ts.tv_sec = timeout_ms / 1000;

    ts.tv_nsec = (timeout_ms % 1000) * 1000000;
@@ -197,7 +212,7 @@ static bool waitpid_with_timeout(pid_t pid, int timeout_ms, int* status) { 


    // Set the signals back the way they were.

    if (sigprocmask(SIG_SETMASK, &old_mask, nullptr) == -1) {

        ALOGW("sigprocmask failed: %s", strerror(errno));

        ALOGW("*** sigprocmask failed: %s\n", strerror(errno));

        if (ret == 0) {

            return false;

        }
@@ -207,22 +222,22 @@ static bool waitpid_with_timeout(pid_t pid, int timeout_ms, int* status) { 
        if (errno == EAGAIN) {

            errno = ETIMEDOUT;

        } else {

            ALOGW("sigtimedwait failed: %s", strerror(errno));

            ALOGW("*** sigtimedwait failed: %s\n", strerror(errno));

        }

        return false;

    }



    pid_t child_pid = waitpid(pid, status, WNOHANG);

    if (child_pid == pid) {

        return true;

    }

    if (child_pid == -1) {

        ALOGW("waitpid failed: %s", strerror(errno));

    child_pid = waitpid(pid, status, WNOHANG);

    if (child_pid != pid) {

        if (child_pid != -1) {

            ALOGW("*** Waiting for pid %d, got pid %d instead\n", pid, child_pid);

        } else {

        ALOGW("Waiting for pid %d, got pid %d instead", pid, child_pid);

            ALOGW("*** waitpid failed: %s\n", strerror(errno));

        }

        return false;

    }

    return true;

}



status_t kill_child(pid_t pid) {

    int status;