[Qemu-devel] [PATCH 3/9] QMP: First half of the new argument checking code

[Luiz Capitulino <lcapitulino@redhat.com>]

This commit introduces the first half of qmp_check_client_args(),
which is the new client argument checker.

It's introduced on top of the existing code, so that there are
no regressions during the transition.

It works this way: the command's args_type field (from
qemu-monitor.hx) is transformed into a qdict. Then we iterate
over it checking whether each mandatory argument has been
provided by the client.

All comunication between the iterator and its caller is done
via the new QMPArgCheckRes type.

Next commit adds the second half of this work: type checking
and invalid argument detection.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
 monitor.c |  107 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 107 insertions(+), 0 deletions(-)

diff --git a/monitor.c b/monitor.c
index bc3cc18..47a0da8 100644
--- a/monitor.c
+++ b/monitor.c
@@ -4259,6 +4259,108 @@ static int invalid_qmp_mode(const Monitor *mon, const char *cmd_name)
     return (qmp_cmd_mode(mon) ? is_cap : !is_cap);
 }
 
+typedef struct QMPArgCheckRes {
+    int result;
+    int skip;
+    QDict *qdict;
+} QMPArgCheckRes;
+
+/*
+ * Check if client passed all mandatory args
+ */
+static void check_mandatory_args(const char *cmd_arg_name,
+                                 QObject *obj, void *opaque)
+{
+    QString *type;
+    QMPArgCheckRes *res = opaque;
+
+    if (res->result < 0) {
+        /* report only the first error */
+        return;
+    }
+
+    type = qobject_to_qstring(obj);
+    assert(type != NULL);
+
+    if (qstring_get_str(type)[0] == 'O') {
+        QemuOptsList *opts_list = qemu_find_opts(cmd_arg_name);
+        assert(opts_list);
+        res->result = check_opts(opts_list, res->qdict);
+        res->skip = 1;
+    } else if (qstring_get_str(type)[0] != '-' &&
+               qstring_get_str(type)[1] != '?' &&
+               !qdict_haskey(res->qdict, cmd_arg_name)) {
+        res->result = -1;
+        qerror_report(QERR_MISSING_PARAMETER, cmd_arg_name);
+    }
+}
+
+static QDict *qdict_from_args_type(const char *args_type)
+{
+    int i;
+    QDict *qdict;
+    QString *key, *type, *cur_qs;
+
+    assert(args_type != NULL);
+
+    qdict = qdict_new();
+
+    if (args_type == NULL || args_type[0] == '\0') {
+        /* no args, empty qdict */
+        goto out;
+    }
+
+    key = qstring_new();
+    type = qstring_new();
+
+    cur_qs = key;
+
+    for (i = 0;; i++) {
+        switch (args_type[i]) {
+            case ',':
+            case '\0':
+                qdict_put(qdict, qstring_get_str(key), type);
+                QDECREF(key);
+                if (args_type[i] == '\0') {
+                    goto out;
+                }
+                type = qstring_new(); /* qdict has ref */
+                cur_qs = key = qstring_new();
+                break;
+            case ':':
+                cur_qs = type;
+                break;
+            default:
+                qstring_append_chr(cur_qs, args_type[i]);
+                break;
+        }
+    }
+
+out:
+    return qdict;
+}
+
+/*
+ * Client argument checking rules:
+ *
+ * 1. Client must provide all mandatory arguments
+ */
+static int qmp_check_client_args(const mon_cmd_t *cmd, QDict *client_args)
+{
+    QDict *cmd_args;
+    QMPArgCheckRes res = { .result = 0, .skip = 0 };
+
+    cmd_args = qdict_from_args_type(cmd->args_type);
+
+    res.qdict = client_args;
+    qdict_iter(cmd_args, check_mandatory_args, &res);
+
+    /* TODO: Check client args type */
+
+    QDECREF(cmd_args);
+    return res.result;
+}
+
 static void handle_qmp_command(JSONMessageParser *parser, QList *tokens)
 {
     int err;
@@ -4334,6 +4436,11 @@ static void handle_qmp_command(JSONMessageParser *parser, QList *tokens)
 
     QDECREF(input);
 
+    err = qmp_check_client_args(cmd, args);
+    if (err < 0) {
+        goto err_out;
+    }
+
     err = monitor_check_qmp_args(cmd, args);
     if (err < 0) {
         goto err_out;
-- 
1.7.1.231.gd0b16