From: Stefan Hajnoczi <stefa...@redhat.com> Although --socket-path=PATH is useful for manual invocations, management tools typically create the UNIX domain socket themselves and pass it to the vhost-user device backend. This way QEMU can be launched immediately with a valid socket. No waiting for the vhost-user device backend is required when fd passing is used.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> --- contrib/virtiofsd/fuse_i.h | 1 + contrib/virtiofsd/fuse_lowlevel.c | 13 ++++++++--- contrib/virtiofsd/fuse_virtio.c | 39 +++++++++++++++++++++++-------- 3 files changed, 40 insertions(+), 13 deletions(-) diff --git a/contrib/virtiofsd/fuse_i.h b/contrib/virtiofsd/fuse_i.h index 5b6ef09df5..4b718f1aec 100644 --- a/contrib/virtiofsd/fuse_i.h +++ b/contrib/virtiofsd/fuse_i.h @@ -68,6 +68,7 @@ struct fuse_session { size_t bufsize; int error; char *vu_socket_path; + int vu_listen_fd; int vu_socketfd; struct fv_VuDev *virtio_dev; }; diff --git a/contrib/virtiofsd/fuse_lowlevel.c b/contrib/virtiofsd/fuse_lowlevel.c index b1f44ca17e..da2f151927 100644 --- a/contrib/virtiofsd/fuse_lowlevel.c +++ b/contrib/virtiofsd/fuse_lowlevel.c @@ -2077,6 +2077,7 @@ static const struct fuse_opt fuse_ll_opts[] = { LL_OPTION("allow_root", deny_others, 1), LL_OPTION("--socket-path=%s", vu_socket_path, 0), LL_OPTION("vhost_user_socket=%s", vu_socket_path, 0), + LL_OPTION("--fd=%d", vu_listen_fd, 0), FUSE_OPT_END }; @@ -2095,6 +2096,7 @@ void fuse_lowlevel_help(void) " -o allow_root allow access by root\n" " --socket-path=PATH path for the vhost-user socket\n" " -o vhost_user_socket=PATH path for the vhost-user socket\n" +" --fd=FDNUM fd number of vhost-user socket\n" " -o auto_unmount auto unmount on process termination\n"); } @@ -2134,6 +2136,7 @@ struct fuse_session *fuse_session_new(struct fuse_args *args, goto out1; } se->fd = -1; + se->vu_listen_fd = -1; se->conn.max_write = UINT_MAX; se->conn.max_readahead = UINT_MAX; @@ -2163,8 +2166,12 @@ struct fuse_session *fuse_session_new(struct fuse_args *args, goto out4; } - if (!se->vu_socket_path) { - fprintf(stderr, "fuse: missing -o vhost_user_socket option\n"); + if (!se->vu_socket_path && se->vu_listen_fd < 0) { + fuse_log(FUSE_LOG_ERR, "fuse: missing --socket-path or --fd option\n"); + goto out4; + } + if (se->vu_socket_path && se->vu_listen_fd >= 0) { + fuse_log(FUSE_LOG_ERR, "fuse: --socket-path and --fd cannot be given together\n"); goto out4; } @@ -2205,7 +2212,7 @@ void fuse_session_unmount(struct fuse_session *se) int fuse_lowlevel_is_virtio(struct fuse_session *se) { - return se->vu_socket_path != NULL; + return !!se->virtio_dev; } #ifdef linux diff --git a/contrib/virtiofsd/fuse_virtio.c b/contrib/virtiofsd/fuse_virtio.c index f52d815596..cc393c3cac 100644 --- a/contrib/virtiofsd/fuse_virtio.c +++ b/contrib/virtiofsd/fuse_virtio.c @@ -635,21 +635,20 @@ int virtio_loop(struct fuse_session *se) return 0; } -int virtio_session_mount(struct fuse_session *se) +static int fv_create_listen_socket(struct fuse_session *se) { struct sockaddr_un un; + /* Nothing to do if fd is already initialized */ + if (se->vu_listen_fd >= 0) { + return 0; + } + if (strlen(se->vu_socket_path) >= sizeof(un.sun_path)) { fuse_log(FUSE_LOG_ERR, "Socket path too long\n"); return -1; } - /* - * Poison the fuse FD so we spot if we accidentally use it; - * DO NOT check for this value, check for fuse_lowlevel_is_virtio() - */ - se->fd = 0xdaff0d11; - /* * Create the Unix socket to communicate with qemu * based on QEMU's vhost-user-bridge @@ -675,15 +674,35 @@ int virtio_session_mount(struct fuse_session *se) return -1; } + se->vu_listen_fd = listen_sock; + return 0; +} + +int virtio_session_mount(struct fuse_session *se) +{ + int ret; + + ret = fv_create_listen_socket(se); + if (ret < 0) { + return ret; + } + + /* + * Poison the fuse FD so we spot if we accidentally use it; + * DO NOT check for this value, check fuse_lowlevel_is_virtio() + */ + se->fd = 0xdaff0d11; + fuse_log(FUSE_LOG_INFO, "%s: Waiting for vhost-user socket connection...\n", __func__); - int data_sock = accept(listen_sock, NULL, NULL); + int data_sock = accept(se->vu_listen_fd, NULL, NULL); if (data_sock == -1) { fuse_log(FUSE_LOG_ERR, "vhost socket accept: %m\n"); - close(listen_sock); + close(se->vu_listen_fd); return -1; } - close(listen_sock); + close(se->vu_listen_fd); + se->vu_listen_fd = -1; fuse_log(FUSE_LOG_INFO, "%s: Received vhost-user socket connection\n", __func__); se->vu_socketfd = data_sock; -- 2.23.0