[Qemu-devel] [RFC 3/3] virtiofsd: add virtiofsctl command-line management tool

[Stefan Hajnoczi <stefanha@redhat.com>]

virtiofsctl can control a running virtiofsd process:

  usage: ./virtiofsctl COMMAND [args...]

  Commands:
    get-log-level       - show current log level
    set-log-level LEVEL - set current log level to one of
                          "err", "warning", "info", "debug"

Make sure it is running in the same DBus session as virtiofsd.  This may
require setting the DBUS_SESSION_BUS_ADDRESS environment variable to the
same value as used by virtiofsd.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 Makefile                        |  3 ++
 Makefile.objs                   |  1 +
 contrib/virtiofsd/Makefile.objs |  3 ++
 contrib/virtiofsd/virtiofsctl.c | 55 +++++++++++++++++++++++++++++++++
 4 files changed, 62 insertions(+)
 create mode 100644 contrib/virtiofsd/virtiofsctl.c

diff --git a/Makefile b/Makefile
index 6b1af33348..d7ed9e7669 100644
--- a/Makefile
+++ b/Makefile
@@ -419,6 +419,7 @@ dummy := $(call unnest-vars,, \
                 ivshmem-client-obj-y \
                 ivshmem-server-obj-y \
                 virtiofsd-obj-y \
+                virtiofsctl-obj-y \
                 rdmacm-mux-obj-y \
                 libvhost-user-obj-y \
                 vhost-user-scsi-obj-y \
@@ -661,6 +662,8 @@ contrib/virtiofsd/gdbus_generated.c-timestamp: $(SRC_PATH)/contrib/virtiofsd/org
 
 virtiofsd$(EXESUF): $(virtiofsd-obj-y) libvhost-user.a $(COMMON_LDADDS)
 	$(call LINK, $^)
+virtiofsctl$(EXESUF): $(virtiofsctl-obj-y)
+	$(call LINK, $^)
 endif
 
 vhost-user-gpu$(EXESUF): $(vhost-user-gpu-obj-y) $(libvhost-user-obj-y) libqemuutil.a libqemustub.a
diff --git a/Makefile.objs b/Makefile.objs
index dfdd7d56ea..326a8abb8e 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -126,6 +126,7 @@ rdmacm-mux-obj-y = contrib/rdmacm-mux/
 vhost-user-input-obj-y = contrib/vhost-user-input/
 vhost-user-gpu-obj-y = contrib/vhost-user-gpu/
 virtiofsd-obj-y = contrib/virtiofsd/
+virtiofsctl-obj-y = contrib/virtiofsd/
 
 ######################################################################
 trace-events-subdirs =
diff --git a/contrib/virtiofsd/Makefile.objs b/contrib/virtiofsd/Makefile.objs
index d59ab60f3d..3f944d493e 100644
--- a/contrib/virtiofsd/Makefile.objs
+++ b/contrib/virtiofsd/Makefile.objs
@@ -11,6 +11,9 @@ virtiofsd-obj-y = buffer.o \
                   gdbus_generated.o \
                   dbus.o
 
+virtiofsctl-obj-y = virtiofsctl.o \
+                    gdbus_generated.o
+
 seccomp.o-cflags := $(SECCOMP_CFLAGS)
 seccomp.o-libs := $(SECCOMP_LIBS)
 
diff --git a/contrib/virtiofsd/virtiofsctl.c b/contrib/virtiofsd/virtiofsctl.c
new file mode 100644
index 0000000000..39bee2b881
--- /dev/null
+++ b/contrib/virtiofsd/virtiofsctl.c
@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include "gdbus_generated.h"
+
+static void get_log_level(Virtiofsd *virtiofsd)
+{
+    const char *value = virtiofsd_get_log_level(virtiofsd);
+
+    printf("%s\n", value ? value : "(null)");
+}
+
+static void set_log_level(Virtiofsd *virtiofsd, const char *value)
+{
+    virtiofsd_set_log_level(virtiofsd, value);
+}
+
+static void usage(const char *progname)
+{
+    printf("usage: %s COMMAND [args...]\n", progname);
+    printf("\n");
+    printf("Commands:\n");
+    printf("  get-log-level       - show current log level\n");
+    printf("  set-log-level LEVEL - set current log level to one of\n");
+    printf("                        \"err\", \"warning\", \"info\", \"debug\"\n");
+    exit(0);
+}
+
+int main(int argc, char **argv)
+{
+    Virtiofsd *virtiofsd;
+    GError *error = NULL;
+
+    if (argc < 2) {
+        usage(argv[0]);
+    }
+
+    virtiofsd = virtiofsd_proxy_new_for_bus_sync(G_BUS_TYPE_SESSION,
+            G_DBUS_PROXY_FLAGS_NONE, "org.qemu.virtiofsd",
+            "/org/qemu/virtiofsd", NULL, &error);
+    if (error) {
+        fprintf(stderr, "%s\n", error->message);
+        g_error_free(error);
+        return 1;
+    }
+
+    if (strcmp(argv[0], "get-log-level") == 0) {
+        get_log_level(virtiofsd);
+    } else if (strcmp(argv[0], "set-log-level") == 0) {
+        if (argc != 3) {
+            usage(argv[0]);
+        }
+        set_log_level(virtiofsd, argv[2]);
+    }
+    g_object_unref(virtiofsd);
+    return 0;
+}
-- 
2.21.0