Chroot implemented. See: http://stackoverflow.com/a/16503389/547223

gistfile1.txt

#include <stdio.h>
#include <unistd.h>

int main(int c, char **v, char **e) {
    int rc; const char *m;
    if ( (m="chdir" ,rc= chdir(v[1]) ) == 0
      && (m="chroot",rc=chroot(v[1]) ) == 0
      && (m="setuid",rc=setuid(getuid())) == 0 )
            m="execve", execve(v[2],v+3,e);
    perror(m);
    return 1;
}