[PATCH] tools/virtiofsd: add support for --socket-group

[PATCH] tools/virtiofsd: add support for --socket-group

[Alex Bennée]

If you like running QEMU as a normal user (very common for TCG runs)
but you have to run virtiofsd as a root user you run into connection
problems. Adding support for an optional --socket-group allows the
users to keep using the command line.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v1
  - tweak documentation and commentary
---
 docs/tools/virtiofsd.rst        |  4 ++++
 tools/virtiofsd/fuse_i.h        |  1 +
 tools/virtiofsd/fuse_lowlevel.c |  6 ++++++
 tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--
 4 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst
index 378594c422a..5a8246b74f8 100644
--- a/docs/tools/virtiofsd.rst
+++ b/docs/tools/virtiofsd.rst
@@ -85,6 +85,10 @@ Options
 
   Listen on vhost-user UNIX domain socket at PATH.
 
+.. option:: --socket-group=GROUP
+
+  Set the vhost-user UNIX domain socket gid to GROUP.
+
 .. option:: --fd=FDNUM
 
   Accept connections from vhost-user UNIX domain socket file descriptor FDNUM.
diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
index 1240828208a..492e002181e 100644
--- a/tools/virtiofsd/fuse_i.h
+++ b/tools/virtiofsd/fuse_i.h
@@ -68,6 +68,7 @@ struct fuse_session {
     size_t bufsize;
     int error;
     char *vu_socket_path;
+    char *vu_socket_group;
     int   vu_listen_fd;
     int   vu_socketfd;
     struct fv_VuDev *virtio_dev;
diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
index 2dd36ec03b6..4d1ba2925d1 100644
--- a/tools/virtiofsd/fuse_lowlevel.c
+++ b/tools/virtiofsd/fuse_lowlevel.c
@@ -2523,6 +2523,7 @@ static const struct fuse_opt fuse_ll_opts[] = {
     LL_OPTION("--debug", debug, 1),
     LL_OPTION("allow_root", deny_others, 1),
     LL_OPTION("--socket-path=%s", vu_socket_path, 0),
+    LL_OPTION("--socket-group=%s", vu_socket_group, 0),
     LL_OPTION("--fd=%d", vu_listen_fd, 0),
     LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),
     FUSE_OPT_END
@@ -2630,6 +2631,11 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
                  "fuse: --socket-path and --fd cannot be given together\n");
         goto out4;
     }
+    if (se->vu_socket_group && !se->vu_socket_path) {
+        fuse_log(FUSE_LOG_ERR,
+                 "fuse: --socket-group can only be used with --socket-path\n");
+        goto out4;
+    }
 
     se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;
 
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index 3b6d16a0417..331f9fc65c5 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -31,6 +31,8 @@
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/un.h>
+#include <sys/types.h>
+#include <grp.h>
 #include <unistd.h>
 
 #include "contrib/libvhost-user/libvhost-user.h"
@@ -924,15 +926,29 @@ static int fv_create_listen_socket(struct fuse_session *se)
 
     /*
      * Unfortunately bind doesn't let you set the mask on the socket,
-     * so set umask to 077 and restore it later.
+     * so set umask appropriately and restore it later.
      */
-    old_umask = umask(0077);
+    if (se->vu_socket_group) {
+        old_umask = umask(S_IROTH | S_IWOTH | S_IXOTH);
+    } else {
+        old_umask = umask(S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH);
+    }
     if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {
         fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");
         close(listen_sock);
         umask(old_umask);
         return -1;
     }
+    if (se->vu_socket_group) {
+        struct group *g = getgrnam(se->vu_socket_group);
+        if (g) {
+            if (!chown(se->vu_socket_path, -1, g->gr_gid)) {
+                fuse_log(FUSE_LOG_WARNING,
+                         "vhost socket failed to set group to %s (%d)\n",
+                         se->vu_socket_group, g->gr_gid);
+            }
+        }
+    }
     umask(old_umask);
 
     if (listen(listen_sock, 1) == -1) {
-- 
2.20.1

Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Daniel P. Berrangé]

On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> If you like running QEMU as a normal user (very common for TCG runs)
> but you have to run virtiofsd as a root user you run into connection
> problems. Adding support for an optional --socket-group allows the
> users to keep using the command line.

If we're going to support this, then I think we need to put it in
the vhost-user.rst specification so we standardize across backends. 



> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>


> 
> ---
> v1
>   - tweak documentation and commentary
> ---
>  docs/tools/virtiofsd.rst        |  4 ++++
>  tools/virtiofsd/fuse_i.h        |  1 +
>  tools/virtiofsd/fuse_lowlevel.c |  6 ++++++
>  tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--
>  4 files changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst
> index 378594c422a..5a8246b74f8 100644
> --- a/docs/tools/virtiofsd.rst
> +++ b/docs/tools/virtiofsd.rst
> @@ -85,6 +85,10 @@ Options
>  
>    Listen on vhost-user UNIX domain socket at PATH.
>  
> +.. option:: --socket-group=GROUP
> +
> +  Set the vhost-user UNIX domain socket gid to GROUP.
> +
>  .. option:: --fd=FDNUM
>  
>    Accept connections from vhost-user UNIX domain socket file descriptor FDNUM.
> diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
> index 1240828208a..492e002181e 100644
> --- a/tools/virtiofsd/fuse_i.h
> +++ b/tools/virtiofsd/fuse_i.h
> @@ -68,6 +68,7 @@ struct fuse_session {
>      size_t bufsize;
>      int error;
>      char *vu_socket_path;
> +    char *vu_socket_group;
>      int   vu_listen_fd;
>      int   vu_socketfd;
>      struct fv_VuDev *virtio_dev;
> diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
> index 2dd36ec03b6..4d1ba2925d1 100644
> --- a/tools/virtiofsd/fuse_lowlevel.c
> +++ b/tools/virtiofsd/fuse_lowlevel.c
> @@ -2523,6 +2523,7 @@ static const struct fuse_opt fuse_ll_opts[] = {
>      LL_OPTION("--debug", debug, 1),
>      LL_OPTION("allow_root", deny_others, 1),
>      LL_OPTION("--socket-path=%s", vu_socket_path, 0),
> +    LL_OPTION("--socket-group=%s", vu_socket_group, 0),
>      LL_OPTION("--fd=%d", vu_listen_fd, 0),
>      LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),
>      FUSE_OPT_END
> @@ -2630,6 +2631,11 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
>                   "fuse: --socket-path and --fd cannot be given together\n");
>          goto out4;
>      }
> +    if (se->vu_socket_group && !se->vu_socket_path) {
> +        fuse_log(FUSE_LOG_ERR,
> +                 "fuse: --socket-group can only be used with --socket-path\n");
> +        goto out4;
> +    }
>  
>      se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;
>  
> diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
> index 3b6d16a0417..331f9fc65c5 100644
> --- a/tools/virtiofsd/fuse_virtio.c
> +++ b/tools/virtiofsd/fuse_virtio.c
> @@ -31,6 +31,8 @@
>  #include <sys/socket.h>
>  #include <sys/types.h>
>  #include <sys/un.h>
> +#include <sys/types.h>
> +#include <grp.h>
>  #include <unistd.h>
>  
>  #include "contrib/libvhost-user/libvhost-user.h"
> @@ -924,15 +926,29 @@ static int fv_create_listen_socket(struct fuse_session *se)
>  
>      /*
>       * Unfortunately bind doesn't let you set the mask on the socket,
> -     * so set umask to 077 and restore it later.
> +     * so set umask appropriately and restore it later.
>       */
> -    old_umask = umask(0077);
> +    if (se->vu_socket_group) {
> +        old_umask = umask(S_IROTH | S_IWOTH | S_IXOTH);
> +    } else {
> +        old_umask = umask(S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH);
> +    }
>      if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {
>          fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");
>          close(listen_sock);
>          umask(old_umask);
>          return -1;
>      }
> +    if (se->vu_socket_group) {
> +        struct group *g = getgrnam(se->vu_socket_group);
> +        if (g) {
> +            if (!chown(se->vu_socket_path, -1, g->gr_gid)) {
> +                fuse_log(FUSE_LOG_WARNING,
> +                         "vhost socket failed to set group to %s (%d)\n",
> +                         se->vu_socket_group, g->gr_gid);
> +            }
> +        }
> +    }
>      umask(old_umask);
>  
>      if (listen(listen_sock, 1) == -1) {
> -- 
> 2.20.1
> 
> 

Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Stefan Hajnoczi]

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On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> If you like running QEMU as a normal user (very common for TCG runs)
> but you have to run virtiofsd as a root user you run into connection
> problems. Adding support for an optional --socket-group allows the
> users to keep using the command line.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> 
> ---
> v1
>   - tweak documentation and commentary
> ---
>  docs/tools/virtiofsd.rst        |  4 ++++
>  tools/virtiofsd/fuse_i.h        |  1 +
>  tools/virtiofsd/fuse_lowlevel.c |  6 ++++++
>  tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--
>  4 files changed, 29 insertions(+), 2 deletions(-)

Dan's suggestion sounds like a good idea to me.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Marc-André Lureau]

Hi

On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> > If you like running QEMU as a normal user (very common for TCG runs)
> > but you have to run virtiofsd as a root user you run into connection
> > problems. Adding support for an optional --socket-group allows the
> > users to keep using the command line.
>
> If we're going to support this, then I think we need to put it in
> the vhost-user.rst specification so we standardize across backends.
>
>

Perhaps. Otoh, I wonder if the backend spec should be more limited to
arguments/introspection that are used by programs.

In this case, I even consider --socket-path to be unnecessary, as a
management layer can/should provide a preopened & setup fd directly.

What do you think?

>
> > Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>
>
> >
> > ---
> > v1
> >   - tweak documentation and commentary
> > ---
> >  docs/tools/virtiofsd.rst        |  4 ++++
> >  tools/virtiofsd/fuse_i.h        |  1 +
> >  tools/virtiofsd/fuse_lowlevel.c |  6 ++++++
> >  tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--
> >  4 files changed, 29 insertions(+), 2 deletions(-)
> >
> > diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst
> > index 378594c422a..5a8246b74f8 100644
> > --- a/docs/tools/virtiofsd.rst
> > +++ b/docs/tools/virtiofsd.rst
> > @@ -85,6 +85,10 @@ Options
> >
> >    Listen on vhost-user UNIX domain socket at PATH.
> >
> > +.. option:: --socket-group=GROUP
> > +
> > +  Set the vhost-user UNIX domain socket gid to GROUP.
> > +
> >  .. option:: --fd=FDNUM
> >
> >    Accept connections from vhost-user UNIX domain socket file descriptor FDNUM.
> > diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
> > index 1240828208a..492e002181e 100644
> > --- a/tools/virtiofsd/fuse_i.h
> > +++ b/tools/virtiofsd/fuse_i.h
> > @@ -68,6 +68,7 @@ struct fuse_session {
> >      size_t bufsize;
> >      int error;
> >      char *vu_socket_path;
> > +    char *vu_socket_group;
> >      int   vu_listen_fd;
> >      int   vu_socketfd;
> >      struct fv_VuDev *virtio_dev;
> > diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
> > index 2dd36ec03b6..4d1ba2925d1 100644
> > --- a/tools/virtiofsd/fuse_lowlevel.c
> > +++ b/tools/virtiofsd/fuse_lowlevel.c
> > @@ -2523,6 +2523,7 @@ static const struct fuse_opt fuse_ll_opts[] = {
> >      LL_OPTION("--debug", debug, 1),
> >      LL_OPTION("allow_root", deny_others, 1),
> >      LL_OPTION("--socket-path=%s", vu_socket_path, 0),
> > +    LL_OPTION("--socket-group=%s", vu_socket_group, 0),
> >      LL_OPTION("--fd=%d", vu_listen_fd, 0),
> >      LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),
> >      FUSE_OPT_END
> > @@ -2630,6 +2631,11 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
> >                   "fuse: --socket-path and --fd cannot be given together\n");
> >          goto out4;
> >      }
> > +    if (se->vu_socket_group && !se->vu_socket_path) {
> > +        fuse_log(FUSE_LOG_ERR,
> > +                 "fuse: --socket-group can only be used with --socket-path\n");
> > +        goto out4;
> > +    }
> >
> >      se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;
> >
> > diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
> > index 3b6d16a0417..331f9fc65c5 100644
> > --- a/tools/virtiofsd/fuse_virtio.c
> > +++ b/tools/virtiofsd/fuse_virtio.c
> > @@ -31,6 +31,8 @@
> >  #include <sys/socket.h>
> >  #include <sys/types.h>
> >  #include <sys/un.h>
> > +#include <sys/types.h>
> > +#include <grp.h>
> >  #include <unistd.h>
> >
> >  #include "contrib/libvhost-user/libvhost-user.h"
> > @@ -924,15 +926,29 @@ static int fv_create_listen_socket(struct fuse_session *se)
> >
> >      /*
> >       * Unfortunately bind doesn't let you set the mask on the socket,
> > -     * so set umask to 077 and restore it later.
> > +     * so set umask appropriately and restore it later.
> >       */
> > -    old_umask = umask(0077);
> > +    if (se->vu_socket_group) {
> > +        old_umask = umask(S_IROTH | S_IWOTH | S_IXOTH);
> > +    } else {
> > +        old_umask = umask(S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH);
> > +    }
> >      if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {
> >          fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");
> >          close(listen_sock);
> >          umask(old_umask);
> >          return -1;
> >      }
> > +    if (se->vu_socket_group) {
> > +        struct group *g = getgrnam(se->vu_socket_group);
> > +        if (g) {
> > +            if (!chown(se->vu_socket_path, -1, g->gr_gid)) {
> > +                fuse_log(FUSE_LOG_WARNING,
> > +                         "vhost socket failed to set group to %s (%d)\n",
> > +                         se->vu_socket_group, g->gr_gid);
> > +            }
> > +        }
> > +    }
> >      umask(old_umask);
> >
> >      if (listen(listen_sock, 1) == -1) {
> > --
> > 2.20.1
> >
> >
>
> Regards,
> Daniel
> --
> |: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
> |: https://libvirt.org         -o-            https://fstop138.berrange.com :|
> |: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|
>
>


-- 
Marc-André Lureau

Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Daniel P. Berrangé]

On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:
> Hi
> 
> On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
> >
> > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> > > If you like running QEMU as a normal user (very common for TCG runs)
> > > but you have to run virtiofsd as a root user you run into connection
> > > problems. Adding support for an optional --socket-group allows the
> > > users to keep using the command line.
> >
> > If we're going to support this, then I think we need to put it in
> > the vhost-user.rst specification so we standardize across backends.
> >
> >
> 
> Perhaps. Otoh, I wonder if the backend spec should be more limited to
> arguments/introspection that are used by programs.
> 
> In this case, I even consider --socket-path to be unnecessary, as a
> management layer can/should provide a preopened & setup fd directly.
> 
> What do you think?

I think there's value in standardization even if it is an option targetted
at human admins, rather than machine usage. You are right though that
something like libvirt would never use --socket-group, or --socket-path.
Even admins would benefit if all programs followed the same naming for
these.  We could document such options as "SHOULD" rather than "MUST"
IOW, we don't mandate --socket-group, but if you're going to provide a
way to control socket group, this option should be used.


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Stefan Hajnoczi]

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On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:
> On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:
> > Hi
> > 
> > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
> > >
> > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> > > > If you like running QEMU as a normal user (very common for TCG runs)
> > > > but you have to run virtiofsd as a root user you run into connection
> > > > problems. Adding support for an optional --socket-group allows the
> > > > users to keep using the command line.
> > >
> > > If we're going to support this, then I think we need to put it in
> > > the vhost-user.rst specification so we standardize across backends.
> > >
> > >
> > 
> > Perhaps. Otoh, I wonder if the backend spec should be more limited to
> > arguments/introspection that are used by programs.
> > 
> > In this case, I even consider --socket-path to be unnecessary, as a
> > management layer can/should provide a preopened & setup fd directly.
> > 
> > What do you think?
> 
> I think there's value in standardization even if it is an option targetted
> at human admins, rather than machine usage. You are right though that
> something like libvirt would never use --socket-group, or --socket-path.
> Even admins would benefit if all programs followed the same naming for
> these.  We could document such options as "SHOULD" rather than "MUST"
> IOW, we don't mandate --socket-group, but if you're going to provide a
> way to control socket group, this option should be used.

I agree.  It's still useful to have a convention that most vhost-user
backend programs follow.

Stefan

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Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Dr. David Alan Gilbert]

* Stefan Hajnoczi (stefanha@redhat.com) wrote:
> On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:
> > On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:
> > > Hi
> > > 
> > > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
> > > >
> > > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> > > > > If you like running QEMU as a normal user (very common for TCG runs)
> > > > > but you have to run virtiofsd as a root user you run into connection
> > > > > problems. Adding support for an optional --socket-group allows the
> > > > > users to keep using the command line.
> > > >
> > > > If we're going to support this, then I think we need to put it in
> > > > the vhost-user.rst specification so we standardize across backends.
> > > >
> > > >
> > > 
> > > Perhaps. Otoh, I wonder if the backend spec should be more limited to
> > > arguments/introspection that are used by programs.
> > > 
> > > In this case, I even consider --socket-path to be unnecessary, as a
> > > management layer can/should provide a preopened & setup fd directly.
> > > 
> > > What do you think?
> > 
> > I think there's value in standardization even if it is an option targetted
> > at human admins, rather than machine usage. You are right though that
> > something like libvirt would never use --socket-group, or --socket-path.
> > Even admins would benefit if all programs followed the same naming for
> > these.  We could document such options as "SHOULD" rather than "MUST"
> > IOW, we don't mandate --socket-group, but if you're going to provide a
> > way to control socket group, this option should be used.
> 
> I agree.  It's still useful to have a convention that most vhost-user
> backend programs follow.

Alex:
  Can you add the doc entry that Stefan and Marc-André are asking
for;  it's probably good they go together.

Dave

> Stefan


--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Alex Bennée]

Dr. David Alan Gilbert <dgilbert@redhat.com> writes:

> * Stefan Hajnoczi (stefanha@redhat.com) wrote:
>> On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:
>> > On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:
>> > > Hi
>> > > 
>> > > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
>> > > >
>> > > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
>> > > > > If you like running QEMU as a normal user (very common for TCG runs)
>> > > > > but you have to run virtiofsd as a root user you run into connection
>> > > > > problems. Adding support for an optional --socket-group allows the
>> > > > > users to keep using the command line.
>> > > >
>> > > > If we're going to support this, then I think we need to put it in
>> > > > the vhost-user.rst specification so we standardize across backends.
>> > > >
>> > > >
>> > > 
>> > > Perhaps. Otoh, I wonder if the backend spec should be more limited to
>> > > arguments/introspection that are used by programs.
>> > > 
>> > > In this case, I even consider --socket-path to be unnecessary, as a
>> > > management layer can/should provide a preopened & setup fd directly.
>> > > 
>> > > What do you think?
>> > 
>> > I think there's value in standardization even if it is an option targetted
>> > at human admins, rather than machine usage. You are right though that
>> > something like libvirt would never use --socket-group, or --socket-path.
>> > Even admins would benefit if all programs followed the same naming for
>> > these.  We could document such options as "SHOULD" rather than "MUST"
>> > IOW, we don't mandate --socket-group, but if you're going to provide a
>> > way to control socket group, this option should be used.
>> 
>> I agree.  It's still useful to have a convention that most vhost-user
>> backend programs follow.
>
> Alex:
>   Can you add the doc entry that Stefan and Marc-André are asking
> for;  it's probably good they go together.

Sure - is docs/interop/vhost-user.rst the master spec for vhost-user
daemons?

>
> Dave
>
>> Stefan


-- 
Alex Bennée

Re: [PATCH] tools/virtiofsd: add support for --socket-group

[Marc-André Lureau]

Hi

On Wed, Mar 18, 2020 at 12:21 AM Alex Bennée <alex.bennee@linaro.org> wrote:
>
>
> Dr. David Alan Gilbert <dgilbert@redhat.com> writes:
>
> > * Stefan Hajnoczi (stefanha@redhat.com) wrote:
> >> On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:
> >> > On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:
> >> > > Hi
> >> > >
> >> > > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
> >> > > >
> >> > > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> >> > > > > If you like running QEMU as a normal user (very common for TCG runs)
> >> > > > > but you have to run virtiofsd as a root user you run into connection
> >> > > > > problems. Adding support for an optional --socket-group allows the
> >> > > > > users to keep using the command line.
> >> > > >
> >> > > > If we're going to support this, then I think we need to put it in
> >> > > > the vhost-user.rst specification so we standardize across backends.
> >> > > >
> >> > > >
> >> > >
> >> > > Perhaps. Otoh, I wonder if the backend spec should be more limited to
> >> > > arguments/introspection that are used by programs.
> >> > >
> >> > > In this case, I even consider --socket-path to be unnecessary, as a
> >> > > management layer can/should provide a preopened & setup fd directly.
> >> > >
> >> > > What do you think?
> >> >
> >> > I think there's value in standardization even if it is an option targetted
> >> > at human admins, rather than machine usage. You are right though that
> >> > something like libvirt would never use --socket-group, or --socket-path.
> >> > Even admins would benefit if all programs followed the same naming for
> >> > these.  We could document such options as "SHOULD" rather than "MUST"
> >> > IOW, we don't mandate --socket-group, but if you're going to provide a
> >> > way to control socket group, this option should be used.
> >>
> >> I agree.  It's still useful to have a convention that most vhost-user
> >> backend programs follow.
> >
> > Alex:
> >   Can you add the doc entry that Stefan and Marc-André are asking
> > for;  it's probably good they go together.
>
> Sure - is docs/interop/vhost-user.rst the master spec for vhost-user
> daemons?

So far, yes. But it might make sense to create a standalone
vhost-user-daemons.rst.



-- 
Marc-André Lureau