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[Qemu-devel] [PATCH] virtiofsd: add man page

Stefan Hajnoczi posted 1 patch 4 years, 8 months ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20190829104133.17418-1-stefanha@redhat.com
Makefile                         |  7 +++
contrib/virtiofsd/virtiofsd.texi | 85 ++++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+)
create mode 100644 contrib/virtiofsd/virtiofsd.texi
[Qemu-devel] [PATCH] virtiofsd: add man page
Posted by Stefan Hajnoczi 4 years, 8 months ago 
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 Makefile                         |  7 +++
 contrib/virtiofsd/virtiofsd.texi | 85 ++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+)
 create mode 100644 contrib/virtiofsd/virtiofsd.texi

diff --git a/Makefile b/Makefile
index a3dfdd6fa8..cc18025753 100644
--- a/Makefile
+++ b/Makefile
@@ -334,6 +334,9 @@ DOCS+=docs/qemu-cpu-models.7
 ifdef CONFIG_VIRTFS
 DOCS+=fsdev/virtfs-proxy-helper.1
 endif
+ifdef CONFIG_LINUX
+DOCS+=contrib/virtiofsd/virtiofsd.1
+endif
 ifdef CONFIG_TRACE_SYSTEMTAP
 DOCS+=scripts/qemu-trace-stap.1
 endif
@@ -834,6 +837,9 @@ ifdef CONFIG_VIRTFS
 	$(INSTALL_DIR) "$(DESTDIR)$(mandir)/man1"
 	$(INSTALL_DATA) fsdev/virtfs-proxy-helper.1 "$(DESTDIR)$(mandir)/man1"
 endif
+ifdef CONFIG_LINUX
+	$(INSTALL_DATA) contrib/virtiofsd.1 "$(DESTDIR)$(mandir)/man1"
+endif
 
 install-datadir:
 	$(INSTALL_DIR) "$(DESTDIR)$(qemu_datadir)"
@@ -1018,6 +1024,7 @@ qemu.1: qemu-doc.texi qemu-options.texi qemu-monitor.texi qemu-monitor-info.texi
 qemu.1: qemu-option-trace.texi
 qemu-img.1: qemu-img.texi qemu-option-trace.texi qemu-img-cmds.texi
 fsdev/virtfs-proxy-helper.1: fsdev/virtfs-proxy-helper.texi
+contrib/virtiofsd/virtiofsd.1: contrib/virtiofsd/virtiofsd.texi
 qemu-nbd.8: qemu-nbd.texi qemu-option-trace.texi
 qemu-ga.8: qemu-ga.texi
 docs/qemu-block-drivers.7: docs/qemu-block-drivers.texi
diff --git a/contrib/virtiofsd/virtiofsd.texi b/contrib/virtiofsd/virtiofsd.texi
new file mode 100644
index 0000000000..eec7fbf4e6
--- /dev/null
+++ b/contrib/virtiofsd/virtiofsd.texi
@@ -0,0 +1,85 @@
+@example
+@c man begin SYNOPSIS
+@command{virtiofsd} [OPTION] @option{--socket-path=}@var{path}|@option{--fd=}@var{fdnum} @option{-o source=}@var{path}
+@c man end
+@end example
+
+@c man begin DESCRIPTION
+
+Share a host directory tree with a guest through a virtio-fs device.  This
+program is a vhost-user backend that implements the virtio-fs device.  Each
+virtio-fs device instance requires its own virtiofsd process.
+
+This program is designed to work with QEMU's @code{--device vhost-user-fs-pci}
+but should work with any virtual machine monitor (VMM) that supports
+vhost-user.  See the EXAMPLES section below.
+
+This program must be run as the root user.  Upon startup the program will
+switch into a new file system namespace with the shared directory tree as its
+root.  This prevents "file system escapes" due to symlinks and other file
+system objects that might lead to files outside the shared directory.  The
+program also sandboxes itself using seccomp(2) to prevent ptrace(2) and other
+vectors that could allow an attacker to compromise the system after gaining
+control of the virtiofsd process.
+
+@c man end
+
+@c man begin OPTIONS
+@table @option
+@item -h, --help
+Print help.
+@item -V, --version
+Print version.
+@item -d, -o debug
+Enable debug output.
+@item --syslog
+Print log messages to syslog instead of stderr.
+@item -o log_level=@var{level}
+Print only log messages matching @var{level} or more severe.  @var{level} is
+one of @code{err}, @code{warn}, @code{info}, or @code{debug}.  The default is
+@var{info}.
+@item -o source=@var{path}
+Share host directory tree located at @var{path}.  This option is required.
+@item --socket-path=@var{path}, -o vhost_user_socket=@var{path}
+Listen on vhost-user UNIX domain socket at @var{path}.
+@item --fd=@var{fdnum}
+Accept connections from vhost-user UNIX domain socket file descriptor @var{fdnum}.  The file descriptor must already be listening for connections.
+@item --thread-pool-size=@var{num}
+Restrict the number of worker threads per request queue to @var{num}.  The default is 64.
+@item --cache=@code{none}|@code{auto}|@code{always}
+Select the desired trade-off between coherency and performance.  @code{none}
+forbids the FUSE client from caching to achieve best coherency at the cost of
+performance.  @code{auto} acts similar to NFS with a 1 second metadata cache
+timeout.  @code{always} sets a long cache lifetime at the expense of coherency.
+@item --writeback
+Enable writeback cache, allowing the FUSE client to buffer and merge write requests.
+@end table
+@c man end
+
+@c man begin EXAMPLES
+Export @code{/var/lib/fs/vm001/} on vhost-user UNIX domain socket @code{/var/run/vm001-vhost-fs.sock}:
+
+@example
+host# virtiofsd --socket-path=/var/run/vm001-vhost-fs.sock -o source=/var/lib/fs/vm001
+host# qemu-system-x86_64 \
+    -chardev socket,id=char0,path=/var/run/vm001-vhost-fs.sock \
+    -device vhost-user-fs-pci,chardev=char0,tag=myfs \
+    -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on \
+    -numa node,memdev=mem \
+    ...
+guest# mount -t virtio_fs \
+    -o default_permissions,allow_other,user_id=0,group_id=0,rootmode=040000,dax \
+    myfs /mnt
+@end example
+@c man end
+
+@ignore
+@setfilename virtiofsd
+@settitle QEMU virtio-fs shared file system daemon
+
+@c man begin AUTHOR
+Copyright (C) 2019 Red Hat, Inc.
+This is free software; see the source for copying conditions.  There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+@c man end
+@end ignore
-- 
2.21.0
Re: [Qemu-devel] [Virtio-fs] [PATCH] virtiofsd: add man page
Posted by Liu Bo 4 years, 8 months ago 
On Thu, Aug 29, 2019 at 11:41:33AM +0100, Stefan Hajnoczi wrote:

Looks good to me, thanks for working this out.

Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>

thanks,
-liubo
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  Makefile                         |  7 +++
>  contrib/virtiofsd/virtiofsd.texi | 85 ++++++++++++++++++++++++++++++++
>  2 files changed, 92 insertions(+)
>  create mode 100644 contrib/virtiofsd/virtiofsd.texi
> 
> diff --git a/Makefile b/Makefile
> index a3dfdd6fa8..cc18025753 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -334,6 +334,9 @@ DOCS+=docs/qemu-cpu-models.7
>  ifdef CONFIG_VIRTFS
>  DOCS+=fsdev/virtfs-proxy-helper.1
>  endif
> +ifdef CONFIG_LINUX
> +DOCS+=contrib/virtiofsd/virtiofsd.1
> +endif
>  ifdef CONFIG_TRACE_SYSTEMTAP
>  DOCS+=scripts/qemu-trace-stap.1
>  endif
> @@ -834,6 +837,9 @@ ifdef CONFIG_VIRTFS
>  	$(INSTALL_DIR) "$(DESTDIR)$(mandir)/man1"
>  	$(INSTALL_DATA) fsdev/virtfs-proxy-helper.1 "$(DESTDIR)$(mandir)/man1"
>  endif
> +ifdef CONFIG_LINUX
> +	$(INSTALL_DATA) contrib/virtiofsd.1 "$(DESTDIR)$(mandir)/man1"
> +endif
>  
>  install-datadir:
>  	$(INSTALL_DIR) "$(DESTDIR)$(qemu_datadir)"
> @@ -1018,6 +1024,7 @@ qemu.1: qemu-doc.texi qemu-options.texi qemu-monitor.texi qemu-monitor-info.texi
>  qemu.1: qemu-option-trace.texi
>  qemu-img.1: qemu-img.texi qemu-option-trace.texi qemu-img-cmds.texi
>  fsdev/virtfs-proxy-helper.1: fsdev/virtfs-proxy-helper.texi
> +contrib/virtiofsd/virtiofsd.1: contrib/virtiofsd/virtiofsd.texi
>  qemu-nbd.8: qemu-nbd.texi qemu-option-trace.texi
>  qemu-ga.8: qemu-ga.texi
>  docs/qemu-block-drivers.7: docs/qemu-block-drivers.texi
> diff --git a/contrib/virtiofsd/virtiofsd.texi b/contrib/virtiofsd/virtiofsd.texi
> new file mode 100644
> index 0000000000..eec7fbf4e6
> --- /dev/null
> +++ b/contrib/virtiofsd/virtiofsd.texi
> @@ -0,0 +1,85 @@
> +@example
> +@c man begin SYNOPSIS
> +@command{virtiofsd} [OPTION] @option{--socket-path=}@var{path}|@option{--fd=}@var{fdnum} @option{-o source=}@var{path}
> +@c man end
> +@end example
> +
> +@c man begin DESCRIPTION
> +
> +Share a host directory tree with a guest through a virtio-fs device.  This
> +program is a vhost-user backend that implements the virtio-fs device.  Each
> +virtio-fs device instance requires its own virtiofsd process.
> +
> +This program is designed to work with QEMU's @code{--device vhost-user-fs-pci}
> +but should work with any virtual machine monitor (VMM) that supports
> +vhost-user.  See the EXAMPLES section below.
> +
> +This program must be run as the root user.  Upon startup the program will
> +switch into a new file system namespace with the shared directory tree as its
> +root.  This prevents "file system escapes" due to symlinks and other file
> +system objects that might lead to files outside the shared directory.  The
> +program also sandboxes itself using seccomp(2) to prevent ptrace(2) and other
> +vectors that could allow an attacker to compromise the system after gaining
> +control of the virtiofsd process.
> +
> +@c man end
> +
> +@c man begin OPTIONS
> +@table @option
> +@item -h, --help
> +Print help.
> +@item -V, --version
> +Print version.
> +@item -d, -o debug
> +Enable debug output.
> +@item --syslog
> +Print log messages to syslog instead of stderr.
> +@item -o log_level=@var{level}
> +Print only log messages matching @var{level} or more severe.  @var{level} is
> +one of @code{err}, @code{warn}, @code{info}, or @code{debug}.  The default is
> +@var{info}.
> +@item -o source=@var{path}
> +Share host directory tree located at @var{path}.  This option is required.
> +@item --socket-path=@var{path}, -o vhost_user_socket=@var{path}
> +Listen on vhost-user UNIX domain socket at @var{path}.
> +@item --fd=@var{fdnum}
> +Accept connections from vhost-user UNIX domain socket file descriptor @var{fdnum}.  The file descriptor must already be listening for connections.
> +@item --thread-pool-size=@var{num}
> +Restrict the number of worker threads per request queue to @var{num}.  The default is 64.
> +@item --cache=@code{none}|@code{auto}|@code{always}
> +Select the desired trade-off between coherency and performance.  @code{none}
> +forbids the FUSE client from caching to achieve best coherency at the cost of
> +performance.  @code{auto} acts similar to NFS with a 1 second metadata cache
> +timeout.  @code{always} sets a long cache lifetime at the expense of coherency.
> +@item --writeback
> +Enable writeback cache, allowing the FUSE client to buffer and merge write requests.
> +@end table
> +@c man end
> +
> +@c man begin EXAMPLES
> +Export @code{/var/lib/fs/vm001/} on vhost-user UNIX domain socket @code{/var/run/vm001-vhost-fs.sock}:
> +
> +@example
> +host# virtiofsd --socket-path=/var/run/vm001-vhost-fs.sock -o source=/var/lib/fs/vm001
> +host# qemu-system-x86_64 \
> +    -chardev socket,id=char0,path=/var/run/vm001-vhost-fs.sock \
> +    -device vhost-user-fs-pci,chardev=char0,tag=myfs \
> +    -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on \
> +    -numa node,memdev=mem \
> +    ...
> +guest# mount -t virtio_fs \
> +    -o default_permissions,allow_other,user_id=0,group_id=0,rootmode=040000,dax \
> +    myfs /mnt
> +@end example
> +@c man end
> +
> +@ignore
> +@setfilename virtiofsd
> +@settitle QEMU virtio-fs shared file system daemon
> +
> +@c man begin AUTHOR
> +Copyright (C) 2019 Red Hat, Inc.
> +This is free software; see the source for copying conditions.  There is NO
> +warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> +@c man end
> +@end ignore
> -- 
> 2.21.0
> 
> _______________________________________________
> Virtio-fs mailing list
> Virtio-fs@redhat.com
> https://www.redhat.com/mailman/listinfo/virtio-fs
Re: [Qemu-devel] [PATCH] virtiofsd: add man page
Posted by Dr. David Alan Gilbert 4 years, 7 months ago 
* Stefan Hajnoczi (stefanha@redhat.com) wrote:
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  Makefile                         |  7 +++
>  contrib/virtiofsd/virtiofsd.texi | 85 ++++++++++++++++++++++++++++++++
>  2 files changed, 92 insertions(+)
>  create mode 100644 contrib/virtiofsd/virtiofsd.texi
> 
> diff --git a/Makefile b/Makefile
> index a3dfdd6fa8..cc18025753 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -334,6 +334,9 @@ DOCS+=docs/qemu-cpu-models.7
>  ifdef CONFIG_VIRTFS
>  DOCS+=fsdev/virtfs-proxy-helper.1
>  endif
> +ifdef CONFIG_LINUX

Is there a reason that's CONFIG_LINUX not CONFIG_VHOST_USER_FS ?
(Although I guess it's guest vs daemon so the two are independent?)

> +DOCS+=contrib/virtiofsd/virtiofsd.1
> +endif
>  ifdef CONFIG_TRACE_SYSTEMTAP
>  DOCS+=scripts/qemu-trace-stap.1
>  endif
> @@ -834,6 +837,9 @@ ifdef CONFIG_VIRTFS
>  	$(INSTALL_DIR) "$(DESTDIR)$(mandir)/man1"
>  	$(INSTALL_DATA) fsdev/virtfs-proxy-helper.1 "$(DESTDIR)$(mandir)/man1"
>  endif
> +ifdef CONFIG_LINUX
> +	$(INSTALL_DATA) contrib/virtiofsd.1 "$(DESTDIR)$(mandir)/man1"

I had to fix that to contrib/virtiofsd/virtiofsd.1 to get make install
happy.

> +endif
>  
>  install-datadir:
>  	$(INSTALL_DIR) "$(DESTDIR)$(qemu_datadir)"
> @@ -1018,6 +1024,7 @@ qemu.1: qemu-doc.texi qemu-options.texi qemu-monitor.texi qemu-monitor-info.texi
>  qemu.1: qemu-option-trace.texi
>  qemu-img.1: qemu-img.texi qemu-option-trace.texi qemu-img-cmds.texi
>  fsdev/virtfs-proxy-helper.1: fsdev/virtfs-proxy-helper.texi
> +contrib/virtiofsd/virtiofsd.1: contrib/virtiofsd/virtiofsd.texi
>  qemu-nbd.8: qemu-nbd.texi qemu-option-trace.texi
>  qemu-ga.8: qemu-ga.texi
>  docs/qemu-block-drivers.7: docs/qemu-block-drivers.texi
> diff --git a/contrib/virtiofsd/virtiofsd.texi b/contrib/virtiofsd/virtiofsd.texi
> new file mode 100644
> index 0000000000..eec7fbf4e6
> --- /dev/null
> +++ b/contrib/virtiofsd/virtiofsd.texi
> @@ -0,0 +1,85 @@
> +@example
> +@c man begin SYNOPSIS
> +@command{virtiofsd} [OPTION] @option{--socket-path=}@var{path}|@option{--fd=}@var{fdnum} @option{-o source=}@var{path}
> +@c man end
> +@end example
> +
> +@c man begin DESCRIPTION
> +
> +Share a host directory tree with a guest through a virtio-fs device.  This
> +program is a vhost-user backend that implements the virtio-fs device.  Each
> +virtio-fs device instance requires its own virtiofsd process.
> +
> +This program is designed to work with QEMU's @code{--device vhost-user-fs-pci}

Should we include the -pci there?

(Merged with the path fix above)

Dave

> +but should work with any virtual machine monitor (VMM) that supports
> +vhost-user.  See the EXAMPLES section below.
> +
> +This program must be run as the root user.  Upon startup the program will
> +switch into a new file system namespace with the shared directory tree as its
> +root.  This prevents "file system escapes" due to symlinks and other file
> +system objects that might lead to files outside the shared directory.  The
> +program also sandboxes itself using seccomp(2) to prevent ptrace(2) and other
> +vectors that could allow an attacker to compromise the system after gaining
> +control of the virtiofsd process.
> +
> +@c man end
> +
> +@c man begin OPTIONS
> +@table @option
> +@item -h, --help
> +Print help.
> +@item -V, --version
> +Print version.
> +@item -d, -o debug
> +Enable debug output.
> +@item --syslog
> +Print log messages to syslog instead of stderr.
> +@item -o log_level=@var{level}
> +Print only log messages matching @var{level} or more severe.  @var{level} is
> +one of @code{err}, @code{warn}, @code{info}, or @code{debug}.  The default is
> +@var{info}.
> +@item -o source=@var{path}
> +Share host directory tree located at @var{path}.  This option is required.
> +@item --socket-path=@var{path}, -o vhost_user_socket=@var{path}
> +Listen on vhost-user UNIX domain socket at @var{path}.
> +@item --fd=@var{fdnum}
> +Accept connections from vhost-user UNIX domain socket file descriptor @var{fdnum}.  The file descriptor must already be listening for connections.
> +@item --thread-pool-size=@var{num}
> +Restrict the number of worker threads per request queue to @var{num}.  The default is 64.
> +@item --cache=@code{none}|@code{auto}|@code{always}
> +Select the desired trade-off between coherency and performance.  @code{none}
> +forbids the FUSE client from caching to achieve best coherency at the cost of
> +performance.  @code{auto} acts similar to NFS with a 1 second metadata cache
> +timeout.  @code{always} sets a long cache lifetime at the expense of coherency.
> +@item --writeback
> +Enable writeback cache, allowing the FUSE client to buffer and merge write requests.
> +@end table
> +@c man end
> +
> +@c man begin EXAMPLES
> +Export @code{/var/lib/fs/vm001/} on vhost-user UNIX domain socket @code{/var/run/vm001-vhost-fs.sock}:
> +
> +@example
> +host# virtiofsd --socket-path=/var/run/vm001-vhost-fs.sock -o source=/var/lib/fs/vm001
> +host# qemu-system-x86_64 \
> +    -chardev socket,id=char0,path=/var/run/vm001-vhost-fs.sock \
> +    -device vhost-user-fs-pci,chardev=char0,tag=myfs \
> +    -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on \
> +    -numa node,memdev=mem \
> +    ...
> +guest# mount -t virtio_fs \
> +    -o default_permissions,allow_other,user_id=0,group_id=0,rootmode=040000,dax \
> +    myfs /mnt
> +@end example
> +@c man end
> +
> +@ignore
> +@setfilename virtiofsd
> +@settitle QEMU virtio-fs shared file system daemon
> +
> +@c man begin AUTHOR
> +Copyright (C) 2019 Red Hat, Inc.
> +This is free software; see the source for copying conditions.  There is NO
> +warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> +@c man end
> +@end ignore
> -- 
> 2.21.0
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
Re: [Qemu-devel] [PATCH] virtiofsd: add man page
Posted by Stefan Hajnoczi 4 years, 7 months ago 
On Tue, Sep 03, 2019 at 04:35:39PM +0100, Dr. David Alan Gilbert wrote:
> * Stefan Hajnoczi (stefanha@redhat.com) wrote:
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  Makefile                         |  7 +++
> >  contrib/virtiofsd/virtiofsd.texi | 85 ++++++++++++++++++++++++++++++++
> >  2 files changed, 92 insertions(+)
> >  create mode 100644 contrib/virtiofsd/virtiofsd.texi
> > 
> > diff --git a/Makefile b/Makefile
> > index a3dfdd6fa8..cc18025753 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -334,6 +334,9 @@ DOCS+=docs/qemu-cpu-models.7
> >  ifdef CONFIG_VIRTFS
> >  DOCS+=fsdev/virtfs-proxy-helper.1
> >  endif
> > +ifdef CONFIG_LINUX
> 
> Is there a reason that's CONFIG_LINUX not CONFIG_VHOST_USER_FS ?
> (Although I guess it's guest vs daemon so the two are independent?)

Yes, this is virtiofsd, not vhost-user-fs-pci.  We don't have a
CONFIG_VIRTIOFSD.

> > +DOCS+=contrib/virtiofsd/virtiofsd.1
> > +endif
> >  ifdef CONFIG_TRACE_SYSTEMTAP
> >  DOCS+=scripts/qemu-trace-stap.1
> >  endif
> > @@ -834,6 +837,9 @@ ifdef CONFIG_VIRTFS
> >  	$(INSTALL_DIR) "$(DESTDIR)$(mandir)/man1"
> >  	$(INSTALL_DATA) fsdev/virtfs-proxy-helper.1 "$(DESTDIR)$(mandir)/man1"
> >  endif
> > +ifdef CONFIG_LINUX
> > +	$(INSTALL_DATA) contrib/virtiofsd.1 "$(DESTDIR)$(mandir)/man1"
> 
> I had to fix that to contrib/virtiofsd/virtiofsd.1 to get make install
> happy.

Thanks for spotting it!

> > +@c man begin DESCRIPTION
> > +
> > +Share a host directory tree with a guest through a virtio-fs device.  This
> > +program is a vhost-user backend that implements the virtio-fs device.  Each
> > +virtio-fs device instance requires its own virtiofsd process.
> > +
> > +This program is designed to work with QEMU's @code{--device vhost-user-fs-pci}
> 
> Should we include the -pci there?
> 
> (Merged with the path fix above)

We could also be more general and say "vhost-user virtio-fs device" to
avoid the issue.

Stefan

Patchew 2.1-devel-0870f84

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