Define QEMU side interfaces used for chroot environment. Signed-off-by: M. Mohan Kumar <mo...@in.ibm.com> --- hw/9pfs/virtio-9p-chroot.c | 87 ++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/hw/9pfs/virtio-9p-chroot.c b/hw/9pfs/virtio-9p-chroot.c index 5150ff0..b466d9a 100644 --- a/hw/9pfs/virtio-9p-chroot.c +++ b/hw/9pfs/virtio-9p-chroot.c @@ -111,6 +111,86 @@ static int chroot_read_request(int sockfd, V9fsFileObjectRequest *request) return 0; } +/* Receive file descriptor and error status from chroot process */ +static int v9fs_receivefd(int sockfd, int *error) +{ + struct msghdr msg = { }; + struct iovec iov; + union MsgControl msg_control; + struct cmsghdr *cmsg; + int retval, fd; + FdInfo fd_info; + + iov.iov_base = &fd_info; + iov.iov_len = sizeof(fd_info); + + memset(&msg, 0, sizeof(msg)); + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = &msg_control; + msg.msg_controllen = sizeof(msg_control); + + retval = recvmsg(sockfd, &msg, 0); + if (retval < 0) { + *error = EIO; + return -EIO; + } + + if (fd_info.fi_flags & FI_SOCKERR) { + return -EIO; + } + + /* If error is set, ancillary data is not present */ + if (fd_info.fi_error) { + *error = fd_info.fi_error; + return -1; + } + + if (!(fd_info.fi_flags & FI_FDVALID)) { + return 0; + } + + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { + if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) || + cmsg->cmsg_level != SOL_SOCKET || + cmsg->cmsg_type != SCM_RIGHTS) { + continue; + } + fd = *((int *)CMSG_DATA(cmsg)); + return fd; + } + + *error = EAGAIN; + return -1; +} + +/* + * V9fsFileObjectRequest is written into the socket by QEMU process. + * Then this request is read by chroot process using read_request function + */ +static int v9fs_write_request(int sockfd, V9fsFileObjectRequest *request) +{ + int retval, length; + char *buff, *buffp; + + length = sizeof(request->data) + request->data.path_len + + request->data.oldpath_len; + + buff = qemu_malloc(length); + buffp = buff; + memcpy(buffp, &request->data, sizeof(request->data)); + buffp += sizeof(request->data); + memcpy(buffp, request->path.path, request->data.path_len); + buffp += request->data.path_len; + memcpy(buffp, request->path.old_path, request->data.oldpath_len); + + retval = qemu_write_full(sockfd, buff, length); + if (retval != length) { + return EIO; + } + return 0; +} + static int chroot_daemonize(int chroot_sock) { sigset_t sigset; @@ -139,6 +219,12 @@ static int chroot_daemonize(int chroot_sock) return 0; } +static void chroot_dummy(void) +{ + (void)v9fs_receivefd; + (void)v9fs_write_request; +} + /* * Fork a process and chroot into the share path. Communication * between qemu process and chroot process happens via socket @@ -184,6 +270,7 @@ int v9fs_chroot(FsContext *fs_ctx) error = qemu_write_full(chroot_sock, &code, sizeof(code)); _exit(1); } + chroot_dummy(); /* * Write 0 to chroot socket to indicate chroot process creation is -- 1.7.3.4