This patch adds send_pipefd() to pass the pipe file descriptor to destination process.
Signed-off-by: Lei Li <li...@linux.vnet.ibm.com> --- include/migration/qemu-file.h | 1 + migration-local.c | 57 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 58 insertions(+), 0 deletions(-) diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h index 39ad0bd..5fad65f 100644 --- a/include/migration/qemu-file.h +++ b/include/migration/qemu-file.h @@ -101,6 +101,7 @@ QEMUFile *qemu_fopen_socket(int fd, const char *mode); QEMUFile *qemu_popen_cmd(const char *command, const char *mode); QEMUFile *qemu_fopen_pipe(int sockfd, const char *mode); +int send_pipefd(int sockfd, int pipefd); int qemu_get_fd(QEMUFile *f); int qemu_fclose(QEMUFile *f); int64_t qemu_ftell(QEMUFile *f); diff --git a/migration-local.c b/migration-local.c index d90b2ff..3875b27 100644 --- a/migration-local.c +++ b/migration-local.c @@ -132,3 +132,60 @@ QEMUFile *qemu_fopen_pipe(int pipefd, const char *mode) return s->file; } + +union MsgControl { + struct cmsghdr cmsg; + char control[CMSG_SPACE(sizeof(int))]; +}; + +/* + * Pass a pipe file descriptor to another process. + * + * Return negative value If pipefd < 0. Return 0 on + * success. + * + */ + +int send_pipefd(int sockfd, int pipefd) +{ + struct cmsghdr *cmsg; + struct iovec iov[1]; + struct msghdr msg; + union MsgControl msg_control; + + char msbuf[1] = { 0x01 }; + int ret; + + iov[0].iov_base = msbuf; + iov[0].iov_len = sizeof(msbuf); + + msg.msg_iov = iov; + msg.msg_iovlen = 1; + + if (pipefd < 0) { + msg.msg_control = NULL; + msg.msg_controllen = 0; + /* Negative status means error */ + msbuf[0] = pipefd; + } else { + msg.msg_control = &msg_control; + msg.msg_controllen = sizeof(msg_control); + + cmsg = &msg_control.cmsg; + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + cmsg->cmsg_len = CMSG_LEN(sizeof(pipefd)); + + /* The pipefd to be passed */ + memcpy(CMSG_DATA(cmsg), &pipefd, sizeof(pipefd)); + } + + do { + ret = sendmsg(sockfd, &msg, 0); + } while (ret < 0 && errno == EINTR); + + if (ret < 0) { + return ret; + } + return 0; +} -- 1.7.7.6