From 6fceacad0e3d27cec6cef4e105c1dabacccb875c Mon Sep 17 00:00:00 2001

From: "plai@redhat.com" <plai@redhat.com>

Date: Thu, 21 Jun 2018 18:54:42 +0200

Subject: [PATCH 163/268] vhost-user: allow slave to send fds via slave channel

RH-Author: plai@redhat.com

Message-id: <1529607285-9942-8-git-send-email-plai@redhat.com>

Patchwork-id: 80935

O-Subject: [RHEL7.6 PATCH BZ 1526645 07/10] vhost-user: allow slave to send fds via slave channel

Bugzilla: 1526645

RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>

RH-Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>

RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

From: Tiwei Bie <tiwei.bie@intel.com>

Introduce VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD protocol

feature to allow slave to send at most 8 descriptors

in each message to master via ancillary data using the

slave channel.

Suggested-by: Michael S. Tsirkin <mst@redhat.com>

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

(cherry picked from commit 5f57fbeaaf7c4cd33152d7f2e449caab4d4209d9)

Signed-off-by: Paul Lai <plai@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 docs/interop/vhost-user.txt |  5 +++++

 hw/virtio/vhost-user.c      | 27 +++++++++++++++++----------

 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt

index 534caab..682a683 100644

--- a/docs/interop/vhost-user.txt

+++ b/docs/interop/vhost-user.txt

@@ -367,6 +367,10 @@ The fd is provided via VHOST_USER_SET_SLAVE_REQ_FD ancillary data.

 A slave may then send VHOST_USER_SLAVE_* messages to the master

 using this fd communication channel.

+If VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD protocol feature is negotiated,

+slave can send file descriptors (at most 8 descriptors in each message)

+to master via ancillary data using this fd communication channel.

+

 Protocol features

 -----------------

@@ -380,6 +384,7 @@ Protocol features

 #define VHOST_USER_PROTOCOL_F_CRYPTO_SESSION 7

 #define VHOST_USER_PROTOCOL_F_PAGEFAULT      8

 #define VHOST_USER_PROTOCOL_F_CONFIG         9

+#define VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD  10

 Master message types

 --------------------

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c

index ebb946a..e8027ad 100644

--- a/hw/virtio/vhost-user.c

+++ b/hw/virtio/vhost-user.c

@@ -30,6 +30,7 @@

 #define VHOST_MEMORY_MAX_NREGIONS    8

 #define VHOST_USER_F_PROTOCOL_FEATURES 30

+#define VHOST_USER_SLAVE_MAX_FDS     8

 /*

  * Maximum size of virtio device config space

@@ -47,6 +48,7 @@ enum VhostUserProtocolFeature {

     VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7,

     VHOST_USER_PROTOCOL_F_PAGEFAULT = 8,

     VHOST_USER_PROTOCOL_F_CONFIG = 9,

+    VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10,

     VHOST_USER_PROTOCOL_F_MAX

 };

@@ -854,10 +856,10 @@ static void slave_read(void *opaque)

     int size, ret = 0;

     struct iovec iov;

     struct msghdr msgh;

-    int fd = -1;

+    int fd[VHOST_USER_SLAVE_MAX_FDS];

     char control[CMSG_SPACE(sizeof(fd))];

     struct cmsghdr *cmsg;

-    size_t fdsize;

+    int i, fdsize = 0;

     memset(&msgh, 0, sizeof(msgh));

     msgh.msg_iov = &iov;

@@ -865,6 +867,8 @@ static void slave_read(void *opaque)

     msgh.msg_control = control;

     msgh.msg_controllen = sizeof(control);

+    memset(fd, -1, sizeof(fd));

+

     /* Read header */

     iov.iov_base = &hd;;

     iov.iov_len = VHOST_USER_HDR_SIZE;

@@ -885,7 +889,7 @@ static void slave_read(void *opaque)

             if (cmsg->cmsg_level == SOL_SOCKET &&

                 cmsg->cmsg_type == SCM_RIGHTS) {

                     fdsize = cmsg->cmsg_len - CMSG_LEN(0);

-                    memcpy(&fd, CMSG_DATA(cmsg), fdsize);

+                    memcpy(fd, CMSG_DATA(cmsg), fdsize);

                     break;

             }

     }

@@ -913,14 +917,15 @@ static void slave_read(void *opaque)

         break;

     default:

         error_report("Received unexpected msg type.");

-        if (fd != -1) {

-            close(fd);

-        }

         ret = -EINVAL;

     }

-    /* Message handlers need to make sure that fd will be consumed. */

-    fd = -1;

+    /* Close the remaining file descriptors. */

+    for (i = 0; i < fdsize; i++) {

+        if (fd[i] != -1) {

+            close(fd[i]);

+        }

+    }

     /*

      * REPLY_ACK feature handling. Other reply types has to be managed

@@ -954,8 +959,10 @@ err:

     qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL);

     close(u->slave_fd);

     u->slave_fd = -1;

-    if (fd != -1) {

-        close(fd);

+    for (i = 0; i < fdsize; i++) {

+        if (fd[i] != -1) {

+            close(fd[i]);

+        }

     }

     return;

 }

-- 

1.8.3.1