gistfile1

import os

def run_execve(program, args=None, env=None):
    if args is None:
        args = [program]
    if env is None:
        env = {}
    # we cannot directly call ll_execve() because it replaces the
    # current process.
    fd_read, fd_write = os.pipe()
    childpid = os.fork()
    if childpid == 0:
        # in the child
        os.close(fd_read)
        os.dup2(fd_write, 1)     # stdout
        os.close(fd_write)
        os.execve(program, args, env)
        assert 0, "should not arrive here"
    else:
        # in the parent
        os.close(fd_write)
        child_stdout = []
        while True:
            data = os.read(fd_read, 4096)
            if not data: break     # closed
            child_stdout.append(data)
        pid, status = os.waitpid(childpid, 0)
        os.close(fd_read)
        print "#", child_stdout
        print pid, status
        return status, ''.join(child_stdout)

# run_execve('/usr/bin/which', ['/usr/bin/which', 'true'])
run_execve('/bin/echo', ['/bin/echo', 'true'])