logwrapper: switch from root to user/group "log" after forking child.

#include <unistd.h>

#include <errno.h>

#include "private/android_filesystem_config.h"

#include "cutils/log.h"

void fatal(const char *msg) {

    } else {

        close(*child_write);

        // switch user and group to "log"

        // this may fail if we are not root, 

        // but in that case switching user/group is unnecessary 

        setgid(AID_LOG);

        setuid(AID_LOG);

        parent(argv[1], *parent_read);

    }