[PATCH v3 10/22] qga: conditionalize schema for commands requiring getifaddrs

[Daniel P . Berrangé]

Rather than creating stubs for every comamnd that just return
QERR_UNSUPPORTED, use 'if' conditions in the QAPI schema to
fully exclude generation of the network interface command on
POSIX platforms lacking getifaddrs().

The command will be rejected at QMP dispatch time instead,
avoiding reimplementing rejection by blocking the stub commands.
This changes the error message for affected commands from

   {"class": "CommandNotFound", "desc": "Command FOO has been disabled"}

to

    {"class": "CommandNotFound", "desc": "The command FOO has not been found"}

This has the additional benefit that the QGA protocol reference
now documents what conditions enable use of the command.

Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>
Reviewed-by: Konstantin Kostiuk <kkost...@redhat.com>
Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
---
 qga/commands-posix.c | 13 -------------
 qga/qapi-schema.json | 15 ++++++++++-----
 2 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 559d71ffae..09d08ee2ca 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -1142,14 +1142,6 @@ error:
     return NULL;
 }
 
-#else
-
-GuestNetworkInterfaceList *qmp_guest_network_get_interfaces(Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-    return NULL;
-}
-
 #endif /* HAVE_GETIFADDRS */
 
 #if !defined(CONFIG_FSFREEZE)
@@ -1222,11 +1214,6 @@ qmp_guest_fstrim(bool has_minimum, int64_t minimum, 
Error **errp)
 /* add unsupported commands to the list of blocked RPCs */
 GList *ga_command_init_blockedrpcs(GList *blockedrpcs)
 {
-#if !defined(HAVE_GETIFADDRS)
-    blockedrpcs = g_list_append(blockedrpcs,
-                              g_strdup("guest-network-get-interfaces"));
-#endif
-
 #if !defined(CONFIG_FSFREEZE)
     {
         const char *list[] = {
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 38483652ac..79ed4f0e21 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -654,7 +654,8 @@
 # Since: 1.1
 ##
 { 'enum': 'GuestIpAddressType',
-  'data': [ 'ipv4', 'ipv6' ] }
+  'data': [ 'ipv4', 'ipv6' ],
+  'if': { 'any': ['CONFIG_WIN32', 'HAVE_GETIFADDRS'] } }
 
 ##
 # @GuestIpAddress:
@@ -670,7 +671,8 @@
 { 'struct': 'GuestIpAddress',
   'data': {'ip-address': 'str',
            'ip-address-type': 'GuestIpAddressType',
-           'prefix': 'int'} }
+           'prefix': 'int'},
+  'if': { 'any': ['CONFIG_WIN32', 'HAVE_GETIFADDRS'] } }
 
 ##
 # @GuestNetworkInterfaceStat:
@@ -702,7 +704,8 @@
             'tx-packets': 'uint64',
             'tx-errs': 'uint64',
             'tx-dropped': 'uint64'
-           } }
+           },
+  'if': { 'any': ['CONFIG_WIN32', 'HAVE_GETIFADDRS'] } }
 
 ##
 # @GuestNetworkInterface:
@@ -722,7 +725,8 @@
   'data': {'name': 'str',
            '*hardware-address': 'str',
            '*ip-addresses': ['GuestIpAddress'],
-           '*statistics': 'GuestNetworkInterfaceStat' } }
+           '*statistics': 'GuestNetworkInterfaceStat' },
+  'if': { 'any': ['CONFIG_WIN32', 'HAVE_GETIFADDRS'] } }
 
 ##
 # @guest-network-get-interfaces:
@@ -734,7 +738,8 @@
 # Since: 1.1
 ##
 { 'command': 'guest-network-get-interfaces',
-  'returns': ['GuestNetworkInterface'] }
+  'returns': ['GuestNetworkInterface'],
+  'if': { 'any': ['CONFIG_WIN32', 'HAVE_GETIFADDRS'] } }
 
 ##
 # @GuestLogicalProcessor:
-- 
2.45.1