QMP: Introduce Human Monitor passthrough command

This command allows QMP clients to execute HMP commands.

Please, check the documentation added to the qmp-commands.hx file
for additional details about the interface and its limitations.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/monitor.c b/monitor.c
index 8cee35d77a..ec31eac8c1 100644
--- a/monitor.c
+++ b/monitor.c
@@ -491,6 +491,44 @@ static int do_qmp_capabilities(Monitor *mon, const QDict *params,
     return 0;
 }
 
+static int mon_set_cpu(int cpu_index);
+static void handle_user_command(Monitor *mon, const char *cmdline);
+
+static int do_hmp_passthrough(Monitor *mon, const QDict *params,
+                              QObject **ret_data)
+{
+    int ret = 0;
+    Monitor *old_mon, hmp;
+    CharDriverState mchar;
+
+    memset(&hmp, 0, sizeof(hmp));
+    qemu_chr_init_mem(&mchar);
+    hmp.chr = &mchar;
+
+    old_mon = cur_mon;
+    cur_mon = &hmp;
+
+    if (qdict_haskey(params, "cpu-index")) {
+        ret = mon_set_cpu(qdict_get_int(params, "cpu-index"));
+        if (ret < 0) {
+            cur_mon = old_mon;
+            qerror_report(QERR_INVALID_PARAMETER_VALUE, "cpu-index", "a CPU number");
+            goto out;
+        }
+    }
+
+    handle_user_command(&hmp, qdict_get_str(params, "command-line"));
+    cur_mon = old_mon;
+
+    if (qemu_chr_mem_osize(hmp.chr) > 0) {
+        *ret_data = QOBJECT(qemu_chr_mem_to_qs(hmp.chr));
+    }
+
+out:
+    qemu_chr_close_mem(hmp.chr);
+    return ret;
+}
+
 static int compare_cmd(const char *name, const char *list)
 {
     const char *p, *pstart;