[Qemu-devel] [RFC][PATCH v1 09/12] guest agent: core marshal/dispatch interfaces

[Michael Roth]

These are basically a stripped-down, guest-side analogue to what's in
qmp_core.c: definitions used by qmp-gen.py-generated marshalling code to
handle dispatch and a registration of command->function mappings (minus
all the bits related to Qmp sessions/server/events).

As a result of that, there is a little bit of code duplication here.
It wouldn't be difficult to make the common bits shareable, but there
isn't much.

The guest agent will use these interfaces to handle dispatch/execution
of requests it gets from the proxy.

Signed-off-by: Michael Roth <address@hidden>
---
 guest-agent-core.c |  143 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 guest-agent-core.h |   21 ++++++++
 2 files changed, 164 insertions(+), 0 deletions(-)
 create mode 100644 guest-agent-core.c
 create mode 100644 guest-agent-core.h

diff --git a/guest-agent-core.c b/guest-agent-core.c
new file mode 100644
index 0000000..6c3b031
--- /dev/null
+++ b/guest-agent-core.c
@@ -0,0 +1,143 @@
+/*
+ * QEMU Guest Agent core functions
+ *
+ * Copyright IBM Corp. 2011
+ *
+ * Authors:
+ *  Adam Litke        <address@hidden>
+ *  Michael Roth      <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include "guest-agent-core.h"
+
+typedef enum QmpCommandType
+{
+    QCT_NORMAL,
+    QCT_ASYNC,
+} QmpCommandType;
+
+typedef struct QmpCommand
+{
+    const char *name;
+    QmpCommandType type;
+    QmpCommandFunc *fn;
+    QmpAsyncCommandFunc *afn;
+    QTAILQ_ENTRY(QmpCommand) node;
+} QmpCommand;
+
+static QTAILQ_HEAD(, QmpCommand) qmp_commands =
+    QTAILQ_HEAD_INITIALIZER(qmp_commands);
+
+QmpMarshalState *qmp_state_get_mstate(QmpState *sess)
+{
+    return NULL;
+}
+
+void qga_register_command(const char *name, QmpCommandFunc *fn)
+{
+    QmpCommand *cmd = qemu_mallocz(sizeof(*cmd));
+
+    cmd->name = name;
+    cmd->type = QCT_NORMAL;
+    cmd->fn = fn;
+    QTAILQ_INSERT_TAIL(&qmp_commands, cmd, node);
+}
+
+static QmpCommand *qmp_find_command(const char *name)
+{
+    QmpCommand *i;
+
+    QTAILQ_FOREACH(i, &qmp_commands, node) {
+        if (strcmp(i->name, name) == 0) {
+            return i;
+        }
+    }
+    return NULL;
+}
+
+static QObject *qga_dispatch_err(QObject *request, Error **errp)
+{
+    const char *command;
+    QDict *args, *dict;
+    QmpCommand *cmd;
+    QObject *ret = NULL;
+
+    if (qobject_type(request) != QTYPE_QDICT) {
+        error_set(errp, QERR_JSON_PARSE_ERROR, "request is not a dictionary");
+        goto out;
+    }
+
+    dict = qobject_to_qdict(request);
+    if (!qdict_haskey(dict, "execute")) {
+        error_set(errp, QERR_JSON_PARSE_ERROR, "no execute key");
+        goto out;
+    }
+
+    command = qdict_get_str(dict, "execute");
+    cmd = qmp_find_command(command);
+    if (cmd == NULL) {
+        error_set(errp, QERR_COMMAND_NOT_FOUND, command);
+        goto out;
+    }
+
+    if (!qdict_haskey(dict, "arguments")) {
+        args = qdict_new();
+    } else {
+        args = qdict_get_qdict(dict, "arguments");
+        QINCREF(args);
+    }
+
+    switch (cmd->type) {
+    case QCT_NORMAL:
+        cmd->fn(NULL, args, &ret, errp);
+        if (ret == NULL) {
+            ret = QOBJECT(qdict_new());
+        }
+        break;
+    case QCT_ASYNC: {
+        QmpCommandState *s = qemu_mallocz(sizeof(*s));
+        // FIXME save async commands and do something
+        // smart if disconnect occurs before completion
+        //s->state = state;
+        s->tag = NULL;
+        if (qdict_haskey(dict, "tag")) {
+            s->tag = qdict_get(dict, "tag");
+            qobject_incref(s->tag);
+        }
+        cmd->afn(args, errp, s);
+        ret = NULL;
+    }
+        break;
+    }
+
+    QDECREF(args);
+
+out:
+    qobject_decref(request);
+
+    return ret;
+}
+
+QObject *qga_dispatch(QObject *request, Error **errp)
+{
+    Error *err = NULL;
+    QObject *ret;
+    QDict *rsp;
+
+    ret = qga_dispatch_err(request, &err);
+
+    rsp = qdict_new();
+    if (err) {
+        qdict_put_obj(rsp, "error", error_get_qobject(err));
+        error_free(err);
+    } else if (ret) {
+        qdict_put_obj(rsp, "return", ret);
+    } else {
+        QDECREF(rsp);
+        return NULL;
+    }
+
+    return QOBJECT(rsp);
+}
diff --git a/guest-agent-core.h b/guest-agent-core.h
new file mode 100644
index 0000000..18126b0
--- /dev/null
+++ b/guest-agent-core.h
@@ -0,0 +1,21 @@
+/*
+ * QEMU Guest Agent core declarations
+ *
+ * Copyright IBM Corp. 2011
+ *
+ * Authors:
+ *  Adam Litke        <address@hidden>
+ *  Michael Roth      <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include "qmp-core.h"
+#include "qapi-types-core.h"
+#include "qmp-marshal-types-core.h"
+#include "qemu-common.h"
+#include "qdict.h"
+
+QObject *qga_dispatch(QObject *obj, Error **errp);
+void qga_register_command(const char *name, QmpCommandFunc *fn);
+void qga_init_marshal(void);
-- 
1.7.0.4