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Blame SOURCES/kvm-virtiofsd-Prevent-multiply-running-with-same-vhost_u.patch

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From ab336e3aea97d76c1b2ac725d19b4518f47dd8f0 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 19:01:59 +0100
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Subject: [PATCH 088/116] virtiofsd: Prevent multiply running with same
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 vhost_user_socket
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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: <20200127190227.40942-85-dgilbert@redhat.com>
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Patchwork-id: 93541
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O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 084/112] virtiofsd: Prevent multiply running with same vhost_user_socket
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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: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
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virtiofsd can run multiply even if the vhost_user_socket is same path.
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  ]# ./virtiofsd -o vhost_user_socket=/tmp/vhostqemu -o source=/tmp/share &
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  [1] 244965
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  virtio_session_mount: Waiting for vhost-user socket connection...
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  ]# ./virtiofsd -o vhost_user_socket=/tmp/vhostqemu -o source=/tmp/share &
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  [2] 244966
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  virtio_session_mount: Waiting for vhost-user socket connection...
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  ]#
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The user will get confused about the situation and maybe the cause of the
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unexpected problem. So it's better to prevent the multiple running.
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Create a regular file under localstatedir directory to exclude the
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vhost_user_socket. To create and lock the file, use qemu_write_pidfile()
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because the API has some sanity checks and file lock.
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Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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  Applied fixes from Stefan's review and moved osdep include
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit 96814800d2b49d18737c36e021c387697ec40c62)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 tools/virtiofsd/fuse_lowlevel.c |  1 +
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 tools/virtiofsd/fuse_virtio.c   | 49 ++++++++++++++++++++++++++++++++++++++++-
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 2 files changed, 49 insertions(+), 1 deletion(-)
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diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
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index 440508a..aac282f 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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@@ -18,6 +18,7 @@
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 #include <assert.h>
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 #include <errno.h>
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+#include <glib.h>
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 #include <limits.h>
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 #include <stdbool.h>
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 #include <stddef.h>
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diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
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index e7bd772..b7948de 100644
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--- a/tools/virtiofsd/fuse_virtio.c
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+++ b/tools/virtiofsd/fuse_virtio.c
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@@ -13,11 +13,12 @@
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 #include "qemu/osdep.h"
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 #include "qemu/iov.h"
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-#include "fuse_virtio.h"
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+#include "qapi/error.h"
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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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 #include <assert.h>
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 #include <errno.h>
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@@ -743,6 +744,42 @@ int virtio_loop(struct fuse_session *se)
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     return 0;
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 }
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+static void strreplace(char *s, char old, char new)
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+{
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+    for (; *s; ++s) {
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+        if (*s == old) {
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+            *s = new;
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+        }
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+    }
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+}
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+
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+static bool fv_socket_lock(struct fuse_session *se)
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+{
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+    g_autofree gchar *sk_name = NULL;
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+    g_autofree gchar *pidfile = NULL;
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+    g_autofree gchar *dir = NULL;
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+    Error *local_err = NULL;
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+
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+    dir = qemu_get_local_state_pathname("run/virtiofsd");
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+
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+    if (g_mkdir_with_parents(dir, S_IRWXU) < 0) {
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+        fuse_log(FUSE_LOG_ERR, "%s: Failed to create directory %s: %s",
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+                 __func__, dir, strerror(errno));
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+        return false;
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+    }
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+
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+    sk_name = g_strdup(se->vu_socket_path);
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+    strreplace(sk_name, '/', '.');
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+    pidfile = g_strdup_printf("%s/%s.pid", dir, sk_name);
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+
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+    if (!qemu_write_pidfile(pidfile, &local_err)) {
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+        error_report_err(local_err);
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+        return false;
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+    }
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+
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+    return true;
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+}
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+
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 static int fv_create_listen_socket(struct fuse_session *se)
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 {
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     struct sockaddr_un un;
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@@ -758,6 +795,16 @@ static int fv_create_listen_socket(struct fuse_session *se)
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         return -1;
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     }
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+    if (!strlen(se->vu_socket_path)) {
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+        fuse_log(FUSE_LOG_ERR, "Socket path is empty\n");
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+        return -1;
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+    }
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+
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+    /* Check the vu_socket_path is already used */
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+    if (!fv_socket_lock(se)) {
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+        return -1;
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+    }
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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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1.8.3.1
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