From: Stefan Hajnoczi <stefanha@redhat.com>

Date: Mon, 27 Jan 2020 19:01:10 +0000

Subject: [PATCH] virtiofsd: add --print-capabilities option

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Add the --print-capabilities option as per vhost-user.rst "Backend

programs conventions".  Currently there are no advertised features.

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

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

(cherry picked from commit 45018fbb0a73ce66fd3dd87ecd2872b45658add4)

---

 docs/interop/vhost-user.json     |  4 +++-

 tools/virtiofsd/fuse_lowlevel.h  |  1 +

 tools/virtiofsd/helper.c         |  2 ++

 tools/virtiofsd/passthrough_ll.c | 12 ++++++++++++

 4 files changed, 18 insertions(+), 1 deletion(-)

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

index da6aaf51c8..d4ea1f7ac5 100644

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

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

@@ -31,6 +31,7 @@

 # @rproc-serial: virtio remoteproc serial link

 # @scsi: virtio scsi

 # @vsock: virtio vsock transport

+# @fs: virtio fs (since 4.2)

 #

 # Since: 4.0

 ##

@@ -50,7 +51,8 @@

       'rpmsg',

       'rproc-serial',

       'scsi',

-      'vsock'

+      'vsock',

+      'fs'

   ]

 }

diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h

index f6b34700af..0d61df8110 100644

--- a/tools/virtiofsd/fuse_lowlevel.h

+++ b/tools/virtiofsd/fuse_lowlevel.h

@@ -1794,6 +1794,7 @@ struct fuse_cmdline_opts {

     int nodefault_subtype;

     int show_version;

     int show_help;

+    int print_capabilities;

     unsigned int max_idle_threads;

 };

diff --git a/tools/virtiofsd/helper.c b/tools/virtiofsd/helper.c

index a3645fc807..b8ec5ac8dc 100644

--- a/tools/virtiofsd/helper.c

+++ b/tools/virtiofsd/helper.c

@@ -40,6 +40,7 @@ static const struct fuse_opt fuse_helper_opts[] = {

     FUSE_HELPER_OPT("--help", show_help),

     FUSE_HELPER_OPT("-V", show_version),

     FUSE_HELPER_OPT("--version", show_version),

+    FUSE_HELPER_OPT("--print-capabilities", print_capabilities),

     FUSE_HELPER_OPT("-d", debug),

     FUSE_HELPER_OPT("debug", debug),

     FUSE_HELPER_OPT("-d", foreground),

@@ -135,6 +136,7 @@ void fuse_cmdline_help(void)

 {

     printf("    -h   --help                print help\n"

            "    -V   --version             print version\n"

+           "    --print-capabilities       print vhost-user.json\n"

            "    -d   -o debug              enable debug output (implies -f)\n"

            "    -f                         foreground operation\n"

            "    --daemonize                run in background\n"

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c

index 037c5d7b26..cd27c09f59 100644

--- a/tools/virtiofsd/passthrough_ll.c

+++ b/tools/virtiofsd/passthrough_ll.c

@@ -1298,6 +1298,14 @@ static struct fuse_lowlevel_ops lo_oper = {

     .lseek = lo_lseek,

 };

+/* Print vhost-user.json backend program capabilities */

+static void print_capabilities(void)

+{

+    printf("{\n");

+    printf("  \"type\": \"fs\"\n");

+    printf("}\n");

+}

+

 int main(int argc, char *argv[])

 {

     struct fuse_args args = FUSE_ARGS_INIT(argc, argv);

@@ -1328,6 +1336,10 @@ int main(int argc, char *argv[])

         fuse_lowlevel_version();

         ret = 0;

         goto err_out1;

+    } else if (opts.print_capabilities) {

+        print_capabilities();

+        ret = 0;

+        goto err_out1;

     }

     if (fuse_opt_parse(&args, &lo, lo_opts, NULL) == -1) {