qga: conditionalize schema for commands unsupported on Windows

Rather than creating stubs for every command that just return
QERR_UNSUPPORTED, use 'if' conditions in the QAPI schema to
fully exclude generation of the commands on Windows.

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 also fixes an accidental inconsistency where some commands
(guest-get-diskstats & guest-get-cpustats) are implemented as
stubs, yet not added to the blockedrpc list. Those change their
error message from

    {"class": "GenericError, "desc": "this feature or command is not currently supported"}

to

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

The final additional benefit is that the QGA protocol reference
now documents what conditions enable use of the command.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20240712132459.3974109-9-berrange@redhat.com>
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>

qga/commands-posix.c

@@ -1280,7 +1280,7 @@ GList *ga_command_init_blockedrpcs(GList *blockedrpcs)
             "guest-get-memory-blocks", "guest-set-memory-blocks",
             "guest-get-memory-block-info",
             NULL};
-        char **p = (char **)list;
+        const char **p = list;
 
         while (*p) {
             blockedrpcs = g_list_append(blockedrpcs, g_strdup(*p++));

qga/commands-win32.c

@@ -1494,11 +1494,6 @@ out:
     }
 }
 
-void qmp_guest_suspend_hybrid(Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-}
-
 static IP_ADAPTER_ADDRESSES *guest_get_adapters_addresses(Error **errp)
 {
     IP_ADAPTER_ADDRESSES *adptr_addrs = NULL;
@@ -1862,12 +1857,6 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error **errp)
     return NULL;
 }
 
-int64_t qmp_guest_set_vcpus(GuestLogicalProcessorList *vcpus, Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-    return -1;
-}
-
 static gchar *
 get_net_error_message(gint error)
 {
@@ -1969,46 +1958,15 @@ done:
     g_free(rawpasswddata);
 }
 
-GuestMemoryBlockList *qmp_guest_get_memory_blocks(Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-    return NULL;
-}
-
-GuestMemoryBlockResponseList *
-qmp_guest_set_memory_blocks(GuestMemoryBlockList *mem_blks, Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-    return NULL;
-}
-
-GuestMemoryBlockInfo *qmp_guest_get_memory_block_info(Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-    return NULL;
-}
-
 /* add unsupported commands to the list of blocked RPCs */
 GList *ga_command_init_blockedrpcs(GList *blockedrpcs)
 {
-    const char *list_unsupported[] = {
-        "guest-suspend-hybrid",
-        "guest-set-vcpus",
-        "guest-get-memory-blocks", "guest-set-memory-blocks",
-        "guest-get-memory-block-info",
-        NULL};
-    char **p = (char **)list_unsupported;
-
-    while (*p) {
-        blockedrpcs = g_list_append(blockedrpcs, g_strdup(*p++));
-    }
-
     if (!vss_init(true)) {
         g_debug("vss_init failed, vss commands are going to be disabled");
         const char *list[] = {
             "guest-get-fsinfo", "guest-fsfreeze-status",
             "guest-fsfreeze-freeze", "guest-fsfreeze-thaw", NULL};
-        p = (char **)list;
+        char **p = (char **)list;
 
         while (*p) {
             blockedrpcs = g_list_append(blockedrpcs, g_strdup(*p++));
@@ -2505,15 +2463,3 @@ char *qga_get_host_name(Error **errp)
 
     return g_utf16_to_utf8(tmp, size, NULL, NULL, NULL);
 }
-
-GuestDiskStatsInfoList *qmp_guest_get_diskstats(Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-    return NULL;
-}
-
-GuestCpuStatsList *qmp_guest_get_cpustats(Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-    return NULL;
-}

qga/qapi-schema.json

@@ -637,7 +637,8 @@
 #
 # Since: 1.1
 ##
-{ 'command': 'guest-suspend-hybrid', 'success-response': false }
+{ 'command': 'guest-suspend-hybrid', 'success-response': false,
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @GuestIpAddressType:
@@ -807,7 +808,8 @@
 ##
 { 'command': 'guest-set-vcpus',
   'data':    {'vcpus': ['GuestLogicalProcessor'] },
-  'returns': 'int' }
+  'returns': 'int',
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @GuestDiskBusType:
@@ -1100,7 +1102,8 @@
 { 'struct': 'GuestMemoryBlock',
   'data': {'phys-index': 'uint64',
            'online': 'bool',
-           '*can-offline': 'bool'} }
+           '*can-offline': 'bool'},
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @guest-get-memory-blocks:
@@ -1116,7 +1119,8 @@
 # Since: 2.3
 ##
 { 'command': 'guest-get-memory-blocks',
-  'returns': ['GuestMemoryBlock'] }
+  'returns': ['GuestMemoryBlock'],
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @GuestMemoryBlockResponseType:
@@ -1139,7 +1143,8 @@
 ##
 { 'enum': 'GuestMemoryBlockResponseType',
   'data': ['success', 'not-found', 'operation-not-supported',
-           'operation-failed'] }
+           'operation-failed'],
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @GuestMemoryBlockResponse:
@@ -1157,7 +1162,8 @@
 { 'struct': 'GuestMemoryBlockResponse',
   'data': { 'phys-index': 'uint64',
             'response': 'GuestMemoryBlockResponseType',
-            '*error-code': 'int' }}
+            '*error-code': 'int' },
+  'if': 'CONFIG_POSIX'}
 
 ##
 # @guest-set-memory-blocks:
@@ -1188,7 +1194,8 @@
 ##
 { 'command': 'guest-set-memory-blocks',
   'data':    {'mem-blks': ['GuestMemoryBlock'] },
-  'returns': ['GuestMemoryBlockResponse'] }
+  'returns': ['GuestMemoryBlockResponse'],
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @GuestMemoryBlockInfo:
@@ -1200,7 +1207,8 @@
 # Since: 2.3
 ##
 { 'struct': 'GuestMemoryBlockInfo',
-  'data': {'size': 'uint64'} }
+  'data': {'size': 'uint64'},
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @guest-get-memory-block-info:
@@ -1212,7 +1220,8 @@
 # Since: 2.3
 ##
 { 'command': 'guest-get-memory-block-info',
-  'returns': 'GuestMemoryBlockInfo' }
+  'returns': 'GuestMemoryBlockInfo',
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @GuestExecStatus:
@@ -1702,7 +1711,8 @@
   'data': {'name': 'str',
            'major': 'uint64',
            'minor': 'uint64',
-           'stats': 'GuestDiskStats' } }
+           'stats': 'GuestDiskStats' },
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @guest-get-diskstats:
@@ -1714,7 +1724,8 @@
 # Since: 7.1
 ##
 { 'command': 'guest-get-diskstats',
-  'returns': ['GuestDiskStatsInfo']
+  'returns': ['GuestDiskStatsInfo'],
+  'if': 'CONFIG_POSIX'
 }
 
 ##
@@ -1727,7 +1738,8 @@
 # Since: 7.1
 ##
 { 'enum': 'GuestCpuStatsType',
-  'data': [ 'linux' ] }
+  'data': [ 'linux' ],
+  'if': 'CONFIG_POSIX' }
 
 
 ##
@@ -1772,7 +1784,8 @@
            '*steal': 'uint64',
            '*guest': 'uint64',
            '*guestnice': 'uint64'
-           } }
+           },
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @GuestCpuStats:
@@ -1786,7 +1799,8 @@
 { 'union': 'GuestCpuStats',
   'base': { 'type': 'GuestCpuStatsType' },
   'discriminator': 'type',
-  'data': { 'linux': 'GuestLinuxCpuStats' } }
+  'data': { 'linux': 'GuestLinuxCpuStats' },
+  'if': 'CONFIG_POSIX' }
 
 ##
 # @guest-get-cpustats:
@@ -1798,5 +1812,6 @@
 # Since: 7.1
 ##
 { 'command': 'guest-get-cpustats',
-  'returns': ['GuestCpuStats']
+  'returns': ['GuestCpuStats'],
+  'if': 'CONFIG_POSIX'
 }