Merge "Fix Perfetto.cpp to silence SELinux warnings"

#include <android-base/unique_fd.h>

#include <errno.h>

#include <fcntl.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <unistd.h>

        // Replace stdin with |readPipe| so the main process can write into it.

        if (dup2(readPipe.get(), STDIN_FILENO) < 0) _exit(1);

        readPipe.reset();

        // Replace stdout/stderr with /dev/null and close any other file

        // descriptor. This is to avoid SELinux complaining about perfetto

        // trying to access files accidentally left open by statsd (i.e. files

        // that have been opened without the O_CLOEXEC flag).

        int devNullFd = open("/dev/null", O_RDWR | O_CLOEXEC);

        if (dup2(devNullFd, STDOUT_FILENO) < 0) _exit(2);

        if (dup2(devNullFd, STDERR_FILENO) < 0) _exit(3);

        close(devNullFd);

        for (int i = 0; i < 1024; i++) {

            if (i != STDIN_FILENO && i != STDOUT_FILENO && i != STDERR_FILENO) close(i);

        }

        execl("/system/bin/perfetto", "perfetto", "--background", "--config", "-", "--dropbox",

              kDropboxTag, nullptr);

        // execl() doesn't return in case of success, if we get here something failed.

        _exit(1);

        // execl() doesn't return in case of success, if we get here something

        // failed.

        _exit(4);

    }

    // Main process.

        return false;

    }

    // This does NOT wait for the full duration of the trace. It just waits until the process

    // has read the config from stdin and detached.

    // This does NOT wait for the full duration of the trace. It just waits until

    // the process has read the config from stdin and detached.

    int childStatus = 0;

    waitpid(pid, &childStatus, 0);

    if (!WIFEXITED(childStatus) || WEXITSTATUS(childStatus) != 0) {