把管道两端和缓冲区一起交给命令对象

1716virCommandSetSendBuffer(virCommand *cmd,1717                        unsigned char **buffer,1718                        size_t buflen)1719{1720    g_autofree unsigned char *localbuf = g_steal_pointer(buffer);1721    int pipefd[2] = { -1, -1 };1722    size_t i;17231724    if (virCommandHasError(cmd))1725        return -1;17261727    if (virPipeQuiet(pipefd) < 0) {1728        cmd->has_error = errno;1729        return -1;1730    }17311732    if (fcntl(pipefd[1], F_SETFL, O_NONBLOCK) < 0) {1733        cmd->has_error = errno;1734        VIR_FORCE_CLOSE(pipefd[0]);1735        VIR_FORCE_CLOSE(pipefd[1]);1736        return -1;1737    }

1739    i = virCommandGetNumSendBuffers(cmd);1740    VIR_REALLOC_N(cmd->sendBuffers, i + 1);17411742    cmd->sendBuffers[i].fd = pipefd[1];1743    cmd->sendBuffers[i].buffer = g_steal_pointer(&localbuf);1744    cmd->sendBuffers[i].buflen = buflen;1745    cmd->sendBuffers[i].offset = 0;17461747    cmd->numSendBuffers++;17481749    virCommandPassFD(cmd, pipefd[0], VIR_COMMAND_PASS_FD_CLOSE_PARENT);17501751    return pipefd[0];1752}

259    conn = virGetConnectSecret();260    if (!conn)261        return -1;262263    memcpy(seclookupdef.u.uuid, secretuuid, sizeof(seclookupdef.u.uuid));264    if (virSecretGetSecretString(conn, &seclookupdef,265                                 VIR_SECRET_USAGE_TYPE_VTPM,266                                 &secret, &secret_len) < 0)267        return -1;268269    *fd = virCommandSetSendBuffer(cmd, &secret, secret_len);270    return 0;271}