[Qemu-devel] [RFC][PATCH 08/10] virtagent: add agent_viewdmesg command

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Add commands to view guest dmesg output. Currently it is a 16K buffer.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hmp-commands.hx |   16 +++++++++
 qmp-commands.hx |   35 +++++++++++++++++++
 virtagent.c     |  100 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 virtagent.h     |    3 ++
 4 files changed, 154 insertions(+), 0 deletions(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index e9a7f4a..0e7a6c9 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1227,6 +1227,22 @@ STEXI
 Echo the file identified by @var{filepath} on the guest filesystem
 ETEXI
 
+    {
+        .name       = "agent_viewdmesg",
+        .args_type  = "",
+        .params     = "",
+        .help       = "View guest dmesg output",
+        .user_print = do_agent_viewdmesg_print,
+        .mhandler.cmd_async = do_agent_viewdmesg,
+        .flags      = MONITOR_CMD_ASYNC,
+    },
+
+STEXI
+@item agent_viewdmesg
+@findex agent_viewdmesg
+View guest dmesg output
+ETEXI
+
 STEXI
 @end table
 ETEXI
diff --git a/qmp-commands.hx b/qmp-commands.hx
index efa2137..dc319b7 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -771,6 +771,41 @@ Example:
 EQMP
 
     {
+        .name       = "agent_viewdmesg",
+        .args_type  = "",
+        .params     = "",
+        .help       = "View guest dmesg output",
+        .user_print = do_agent_viewdmesg_print,
+        .mhandler.cmd_async = do_agent_viewdmesg,
+        .flags      = MONITOR_CMD_ASYNC,
+    },
+
+STEXI
+@item agent_viewdmesg
+@findex agent_viewdmesg
+View guest dmesg output
+ETEXI
+SQMP
+agent_viewdmesg
+--------
+
+View guest dmesg output
+
+Arguments:
+
+(none)
+
+Example:
+
+-> { "execute": "agent_viewdmesg" }
+<- { "return": {
+       "contents": "[353487.942215] usb 1-4: USB disconnect, address 9\n..."
+     }
+   }
+
+EQMP
+
+    {
         .name       = "qmp_capabilities",
         .args_type  = "",
         .params     = "",
diff --git a/virtagent.c b/virtagent.c
index 8059d00..cae9a85 100644
--- a/virtagent.c
+++ b/virtagent.c
@@ -196,3 +196,103 @@ int do_agent_viewfile(Monitor *mon, const QDict *mon_params,
 
     return 0;
 }
+
+void do_agent_viewdmesg_print(Monitor *mon, const QObject *data)
+{
+    QDict *qdict;
+    const char *contents = NULL;
+    int i;
+
+    qdict = qobject_to_qdict(data);
+    if (!qdict_haskey(qdict, "contents")) {
+        return;
+    }
+
+    contents = qdict_get_str(qdict, "contents");
+    if (contents != NULL) {
+         /* monitor_printf truncates so do it in chunks. also, file_contents
+          * may not be null-termed at proper location so explicitly calc
+          * last chunk sizes */
+        for (i = 0; i < strlen(contents); i += 1024) {
+            monitor_printf(mon, "%.1024s", contents + i);
+        }
+    }
+    monitor_printf(mon, "\n");
+}
+
+static void do_agent_viewdmesg_cb(void *opaque)
+{
+    RPCRequest *rpc_data = opaque;
+    xmlrpc_value *resp = NULL;
+    char *dmesg = NULL;
+    int ret;
+    xmlrpc_env env;
+    QDict *qdict = qdict_new();
+
+    if (rpc_data->resp_xml == NULL) {
+        monitor_printf(rpc_data->mon, "error handling RPC request");
+        goto out_no_resp;
+    }
+
+    xmlrpc_env_init(&env);
+    resp = xmlrpc_parse_response(&env, rpc_data->resp_xml,
+                                 rpc_data->resp_xml_len);
+    if (rpc_has_error(&env)) {
+        ret = -1;
+        goto out_no_resp;
+    }
+
+    xmlrpc_parse_value(&env, resp, "s", &dmesg);
+    if (rpc_has_error(&env)) {
+        ret = -1;
+        goto out;
+    }
+
+    if (dmesg != NULL) {
+        qdict_put(qdict, "contents", qstring_from_str(dmesg));
+    }
+
+out:
+    qemu_free(rpc_data->resp_xml);
+    xmlrpc_DECREF(resp);
+out_no_resp:
+    rpc_data->mon_cb(rpc_data->mon_data, QOBJECT(qdict));
+    qemu_free(rpc_data);
+}
+
+/*
+ * do_agent_viewdmesg(): View guest dmesg output
+ */
+int do_agent_viewdmesg(Monitor *mon, const QDict *mon_params,
+                      MonitorCompletion cb, void *opaque)
+{
+    xmlrpc_env env;
+    xmlrpc_value *params;
+    RPCRequest *rpc_data;
+    int ret;
+
+    xmlrpc_env_init(&env);
+
+    params = xmlrpc_build_value(&env, "(n)");
+    if (rpc_has_error(&env)) {
+        return -1;
+    }
+
+    rpc_data = qemu_mallocz(sizeof(RPCRequest));
+    rpc_data->cb = do_agent_viewdmesg_cb;
+    rpc_data->mon = mon;
+    rpc_data->mon_cb = cb;
+    rpc_data->mon_data = opaque;
+
+    ret = rpc_execute(&env, "getdmesg", params, rpc_data);
+    if (ret == -EREMOTE) {
+        monitor_printf(mon, "RPC Failed (%i): %s\n", env.fault_code,
+                       env.fault_string);
+        return -1;
+    } else if (ret == -1) {
+        monitor_printf(mon, "RPC communication error\n");
+        return -1;
+    }
+
+    return 0;
+}
diff --git a/virtagent.h b/virtagent.h
index d027eac..82a6924 100644
--- a/virtagent.h
+++ b/virtagent.h
@@ -25,5 +25,8 @@
 void do_agent_viewfile_print(Monitor *mon, const QObject *qobject);
 int do_agent_viewfile(Monitor *mon, const QDict *mon_params,
                       MonitorCompletion cb, void *opaque);
+void do_agent_viewdmesg_print(Monitor *mon, const QObject *qobject);
+int do_agent_viewdmesg(Monitor *mon, const QDict *mon_params,
+                      MonitorCompletion cb, void *opaque);
 
 #endif /* VIRTAGENT_H */
-- 
1.7.0.4