[PATCH] tools/xl: hide xenstore-features behind option

[Juergen Gross <jgross@xxxxxxxx>]

In order to be able to use "xl info" before Xenstore has been started
or after it has crashed, hide obtaining the available Xenstore features
behind the new option "-x".

Fixes: ecce7970cfe7 ("tools/xl: add available Xenstore features to xl info 
output")
Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 docs/man/xl.1.pod.in     |  4 ++++
 docs/man/xl.cfg.5.pod.in |  2 +-
 tools/xl/xl_info.c       | 14 ++++++++++----
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/docs/man/xl.1.pod.in b/docs/man/xl.1.pod.in
index fe38724b2b..88ccf7ad82 100644
--- a/docs/man/xl.1.pod.in
+++ b/docs/man/xl.1.pod.in
@@ -996,6 +996,10 @@ B<OPTIONS>
 
 List host NUMA topology information
 
+=item B<-x>, B<--xenstore>
+
+Show Xenstore features available.
+
 =back
 
 =item B<top>
diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index f0c920b39d..acff45d308 100644
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -743,7 +743,7 @@ condition.
 =back
 
 The features supported by the running Xenstore instance can be retrieved
-via the B<xl info> command in dom0.
+via the B<xl info -x> command in dom0.
 
 The default value is B<0xffffffff>, meaning that all possible Xenstore
 features are visible by the guest.
diff --git a/tools/xl/xl_info.c b/tools/xl/xl_info.c
index eb019e3ee9..d3583cbf8f 100644
--- a/tools/xl/xl_info.c
+++ b/tools/xl/xl_info.c
@@ -353,7 +353,7 @@ static void output_xenstore_info(void)
     xs_close(xsh);
 }
 
-static void print_info(int numa)
+static void print_info(int numa, bool xs)
 {
     output_nodeinfo();
 
@@ -365,7 +365,8 @@ static void print_info(int numa)
     }
     output_xeninfo();
 
-    output_xenstore_info();
+    if (xs)
+        output_xenstore_info();
 
     maybe_printf("xend_config_format     : 4\n");
 
@@ -631,14 +632,19 @@ int main_info(int argc, char **argv)
     int opt;
     static struct option opts[] = {
         {"numa", 0, 0, 'n'},
+        {"xenstore", 0, 0, 'x'},
         COMMON_LONG_OPTS
     };
     int numa = 0;
+    bool xs = false;
 
-    SWITCH_FOREACH_OPT(opt, "n", opts, "info", 0) {
+    SWITCH_FOREACH_OPT(opt, "nx", opts, "info", 0) {
     case 'n':
         numa = 1;
         break;
+    case 'x':
+        xs = true;
+        break;
     }
 
     /*
@@ -648,7 +654,7 @@ int main_info(int argc, char **argv)
     if (numa == 0 && argc > optind)
         info_name = argv[optind];
 
-    print_info(numa);
+    print_info(numa, xs);
     return 0;
 }
 
-- 
2.43.0