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Blame SOURCES/kvm-virtiofsd-Open-vhost-connection-instead-of-mounting.patch

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From a96042f05eaf494fbe26a9cbd940f5f815f782f9 Mon Sep 17 00:00:00 2001
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Date: Mon, 27 Jan 2020 19:00:56 +0100
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Subject: [PATCH 025/116] virtiofsd: Open vhost connection instead of mounting
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Message-id: <20200127190227.40942-22-dgilbert@redhat.com>
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Patchwork-id: 93476
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O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 021/112] virtiofsd: Open vhost connection instead of mounting
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Bugzilla: 1694164
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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When run with vhost-user options we conect to the QEMU instead
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via a socket.  Start this off by creating the socket.
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit d14bf584dd965821e80d14c16d9292a464b1ab85)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 tools/virtiofsd/fuse_i.h        |  7 ++--
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 tools/virtiofsd/fuse_lowlevel.c | 55 ++++------------------------
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 tools/virtiofsd/fuse_virtio.c   | 79 +++++++++++++++++++++++++++++++++++++++++
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 tools/virtiofsd/fuse_virtio.h   | 23 ++++++++++++
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 4 files changed, 114 insertions(+), 50 deletions(-)
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 create mode 100644 tools/virtiofsd/fuse_virtio.c
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 create mode 100644 tools/virtiofsd/fuse_virtio.h
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diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
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index 26b1a7d..82d6ac7 100644
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--- a/tools/virtiofsd/fuse_i.h
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+++ b/tools/virtiofsd/fuse_i.h
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@@ -6,9 +6,10 @@
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  * See the file COPYING.LIB
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  */
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-#define FUSE_USE_VERSION 31
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-
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+#ifndef FUSE_I_H
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+#define FUSE_I_H
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+#define FUSE_USE_VERSION 31
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 #include "fuse.h"
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 #include "fuse_lowlevel.h"
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@@ -101,3 +102,5 @@ void fuse_session_process_buf_int(struct fuse_session *se,
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 /* room needed in buffer to accommodate header */
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 #define FUSE_BUFFER_HEADER_SIZE 0x1000
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+
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+#endif
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diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
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index 17e8718..5df124e 100644
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--- a/tools/virtiofsd/fuse_lowlevel.c
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+++ b/tools/virtiofsd/fuse_lowlevel.c
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@@ -14,6 +14,7 @@
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 #include "standard-headers/linux/fuse.h"
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 #include "fuse_misc.h"
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 #include "fuse_opt.h"
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+#include "fuse_virtio.h"
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 #include <assert.h>
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 #include <errno.h>
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@@ -2202,6 +2203,11 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
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         goto out4;
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     }
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+    if (!se->vu_socket_path) {
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+        fprintf(stderr, "fuse: missing -o vhost_user_socket option\n");
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+        goto out4;
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+    }
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+
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     se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;
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     list_init_req(&se->list);
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@@ -2224,54 +2230,7 @@ out1:
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 int fuse_session_mount(struct fuse_session *se)
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 {
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-    int fd;
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-
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-    /*
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-     * Make sure file descriptors 0, 1 and 2 are open, otherwise chaos
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-     * would ensue.
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-     */
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-    do {
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-        fd = open("/dev/null", O_RDWR);
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-        if (fd > 2) {
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-            close(fd);
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-        }
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-    } while (fd >= 0 && fd <= 2);
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-
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-    /*
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-     * To allow FUSE daemons to run without privileges, the caller may open
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-     * /dev/fuse before launching the file system and pass on the file
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-     * descriptor by specifying /dev/fd/N as the mount point. Note that the
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-     * parent process takes care of performing the mount in this case.
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-     */
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-    fd = fuse_mnt_parse_fuse_fd(mountpoint);
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-    if (fd != -1) {
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-        if (fcntl(fd, F_GETFD) == -1) {
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-            fuse_log(FUSE_LOG_ERR, "fuse: Invalid file descriptor /dev/fd/%u\n",
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-                     fd);
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-            return -1;
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-        }
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-        se->fd = fd;
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-        return 0;
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-    }
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-
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-    /* Open channel */
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-    fd = fuse_kern_mount(mountpoint, se->mo);
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-    if (fd == -1) {
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-        return -1;
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-    }
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-    se->fd = fd;
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-
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-    /* Save mountpoint */
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-    se->mountpoint = strdup(mountpoint);
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-    if (se->mountpoint == NULL) {
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-        goto error_out;
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-    }
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-
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-    return 0;
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-
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-error_out:
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-    fuse_kern_unmount(mountpoint, fd);
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-    return -1;
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+    return virtio_session_mount(se);
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 }
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 int fuse_session_fd(struct fuse_session *se)
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diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
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new file mode 100644
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index 0000000..cbef6ff
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--- /dev/null
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+++ b/tools/virtiofsd/fuse_virtio.c
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@@ -0,0 +1,79 @@
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+/*
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+ * virtio-fs glue for FUSE
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+ * Copyright (C) 2018 Red Hat, Inc. and/or its affiliates
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+ *
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+ * Authors:
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+ *   Dave Gilbert  <dgilbert@redhat.com>
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+ *
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+ * Implements the glue between libfuse and libvhost-user
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+ *
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+ * This program can be distributed under the terms of the GNU LGPLv2.
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+ * See the file COPYING.LIB
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+ */
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+
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+#include "fuse_i.h"
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+#include "standard-headers/linux/fuse.h"
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+#include "fuse_misc.h"
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+#include "fuse_opt.h"
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+#include "fuse_virtio.h"
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+
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+#include <stdint.h>
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+#include <stdio.h>
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+#include <string.h>
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+#include <sys/socket.h>
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+#include <sys/types.h>
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+#include <sys/un.h>
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+#include <unistd.h>
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+
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+/* From spec */
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+struct virtio_fs_config {
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+    char tag[36];
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+    uint32_t num_queues;
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+};
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+
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+int virtio_session_mount(struct fuse_session *se)
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+{
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+    struct sockaddr_un un;
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+    mode_t old_umask;
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+
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+    if (strlen(se->vu_socket_path) >= sizeof(un.sun_path)) {
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+        fuse_log(FUSE_LOG_ERR, "Socket path too long\n");
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+        return -1;
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+    }
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+
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+    se->fd = -1;
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+
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+    /*
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+     * Create the Unix socket to communicate with qemu
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+     * based on QEMU's vhost-user-bridge
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+     */
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+    unlink(se->vu_socket_path);
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+    strcpy(un.sun_path, se->vu_socket_path);
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+    size_t addr_len = sizeof(un);
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+
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+    int listen_sock = socket(AF_UNIX, SOCK_STREAM, 0);
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+    if (listen_sock == -1) {
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+        fuse_log(FUSE_LOG_ERR, "vhost socket creation: %m\n");
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+        return -1;
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+    }
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+    un.sun_family = AF_UNIX;
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+
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+    /*
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+     * Unfortunately bind doesn't let you set the mask on the socket,
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+     * so set umask to 077 and restore it later.
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+     */
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+    old_umask = umask(0077);
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+    if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {
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+        fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");
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+        umask(old_umask);
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+        return -1;
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+    }
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+    umask(old_umask);
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+
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+    if (listen(listen_sock, 1) == -1) {
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+        fuse_log(FUSE_LOG_ERR, "vhost socket listen: %m\n");
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+        return -1;
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+    }
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+
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+    return -1;
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+}
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diff --git a/tools/virtiofsd/fuse_virtio.h b/tools/virtiofsd/fuse_virtio.h
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new file mode 100644
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index 0000000..8f2edb6
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--- /dev/null
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+++ b/tools/virtiofsd/fuse_virtio.h
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@@ -0,0 +1,23 @@
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+/*
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+ * virtio-fs glue for FUSE
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+ * Copyright (C) 2018 Red Hat, Inc. and/or its affiliates
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+ *
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+ * Authors:
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+ *   Dave Gilbert  <dgilbert@redhat.com>
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+ *
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+ * Implements the glue between libfuse and libvhost-user
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+ *
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+ * This program can be distributed under the terms of the GNU LGPLv2.
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+ *  See the file COPYING.LIB
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+ */
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+
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+#ifndef FUSE_VIRTIO_H
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+#define FUSE_VIRTIO_H
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+
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+#include "fuse_i.h"
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+
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+struct fuse_session;
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+
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+int virtio_session_mount(struct fuse_session *se);
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+
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+#endif
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-- 
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1.8.3.1
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