rpc: improve error message for bounds check

If we exceed a fixed limit in RPC code we get a horrible message
like this, if the parameter type is a 'string', because we forgot
to initialize the error message type field:

  $ virsh snapshot-list ostack1
  error: too many remote undefineds: 1329 > 1024

It would also be useful to know which RPC call and field was
exceeded. So this patch makes us report:

  $ virsh snapshot-list ostack1
  error: too many remote undefineds: 1329 > 1024,
  in parameter 'names' for 'virDomainSnapshotListNames'

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

diff --git a/src/rpc/gendispatch.pl b/src/rpc/gendispatch.pl
index def88d4f96d30042431933811e1800e3d5eef4c1..e7a48d578a286994e35396ba0df2e079c0529613 100755 (executable)
--- a/src/rpc/gendispatch.pl
+++ b/src/rpc/gendispatch.pl
@@ -1513,6 +1513,7 @@ elsif ($mode eq "client") {
                     $single_ret_list_name = $1;
                     $single_ret_list_max_var = "max$1";
                     $single_ret_list_max_define = $2;
+                    $single_ret_list_error_msg_type = "string";
                 } elsif ($ret_member =~ m/^(admin|remote)_nonnull_string (\S+)<\S+>;/) {
                     # error out on unannotated arrays
                     die "$1_nonnull_string array without insert@<offset> annotation: $ret_member";
@@ -1790,7 +1791,8 @@ elsif ($mode eq "client") {
             print "\n";
             print "    if ($single_ret_list_max_var > $single_ret_list_max_define) {\n";
             print "        virReportError(VIR_ERR_RPC,\n";
-            print "                       _(\"too many remote ${single_ret_list_error_msg_type}s: %d > %d\"),\n";
+            print "                       _(\"too many remote ${single_ret_list_error_msg_type}s: %d > %d,\"\n";
+            print "                         \"in parameter '$single_ret_list_name' for 'vir$call->{ProcName}'\"),\n";
             print "                       $single_ret_list_max_var, $single_ret_list_max_define);\n";
             print "        goto done;\n";
             print "    }\n";
@@ -1856,7 +1858,8 @@ elsif ($mode eq "client") {
             $modern_ret_as_list) {
             print "    if (ret.$single_ret_list_name.${single_ret_list_name}_len > $single_ret_list_max_var) {\n";
             print "        virReportError(VIR_ERR_RPC,\n";
-            print "                       _(\"too many remote ${single_ret_list_error_msg_type}s: %d > %d\"),\n";
+            print "                       _(\"too many remote ${single_ret_list_error_msg_type}s: %d > %d,\"\n";
+            print "                         \"in parameter '$single_ret_list_name' for 'vir$call->{ProcName}'\"),\n";
             print "                       ret.$single_ret_list_name.${single_ret_list_name}_len, $single_ret_list_max_var);\n";
             print "        goto cleanup;\n";
             print "    }\n";