[Virtio-fs] [PATCH] virtiofsd: add man page

[Stefan Hajnoczi]

Signed-off-by: Stefan Hajnoczi <stefanha at 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 @@
+ at example
+ at c man begin SYNOPSIS
+ at command{virtiofsd} [OPTION] @option{--socket-path=}@var{path}|@option{--fd=}@var{fdnum} @option{-o source=}@var{path}
+ at c man end
+ at end example
+
+ at 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.
+
+ at c man end
+
+ at c man begin OPTIONS
+ at table @option
+ at item -h, --help
+Print help.
+ at item -V, --version
+Print version.
+ at item -d, -o debug
+Enable debug output.
+ at item --syslog
+Print log messages to syslog instead of stderr.
+ at 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
+ at var{info}.
+ at item -o source=@var{path}
+Share host directory tree located at @var{path}.  This option is required.
+ at item --socket-path=@var{path}, -o vhost_user_socket=@var{path}
+Listen on vhost-user UNIX domain socket at @var{path}.
+ at 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.
+ at item --thread-pool-size=@var{num}
+Restrict the number of worker threads per request queue to @var{num}.  The default is 64.
+ at 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.
+ at item --writeback
+Enable writeback cache, allowing the FUSE client to buffer and merge write requests.
+ at end table
+ at c man end
+
+ at c man begin EXAMPLES
+Export @code{/var/lib/fs/vm001/} on vhost-user UNIX domain socket @code{/var/run/vm001-vhost-fs.sock}:
+
+ at 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
+ at end example
+ at c man end
+
+ at ignore
+ at setfilename virtiofsd
+ at settitle QEMU virtio-fs shared file system daemon
+
+ at 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.
+ at c man end
+ at end ignore
-- 
2.21.0