vmctl: input-control library over QMP and Linux uinput

QMP client and driver, Linux uinput driver, keymap, open/power helpers, public header, and CMake build.
2026-06-18 02:36:37 +03:00 · 2026-06-17 12:55:36 +03:00
commit 9b75494380
12 changed files with 861 additions and 0 deletions
@@ -0,0 +1,94 @@
+/* qmp_driver.c — QMP input driver: serialises an input batch into a single
+ * input-send-event command and sends it in one round-trip. No guest driver is
+ * required. Switches on vmctl_ev_kind (never on magic numbers). */
+
+#include "driver.h"
+#include "keymap.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+static const char* btn_names[] = {
+    "left", "right", "middle", "side", "extra", "forward", "back", "task"
+};
+#define BTN_NAMES_LEN ((int)(sizeof btn_names / sizeof btn_names[0]))
+
+static int qmp_driver_send(vmctl_t* v, const vmctl_batch* b) {
+    char json[8192];
+    int  pos = 0;
+
+    pos += snprintf(json + pos, (int)sizeof json - pos,
+                    "{\"execute\":\"input-send-event\",\"arguments\":{\"events\":[");
+
+    for (int i = 0; i < b->count; i++) {
+        if (i > 0)
+            pos += snprintf(json + pos, (int)sizeof json - pos, ",");
+
+        int    code  = b->ev[i].code;
+        int    value = b->ev[i].value;
+        double scl   = b->ev[i].scroll;
+
+        switch ((vmctl_ev_kind)b->ev[i].kind) {
+        case VMCTL_EV_ABS:
+            pos += snprintf(json + pos, (int)sizeof json - pos,
+                            "{\"type\":\"abs\",\"data\":{\"axis\":\"%s\",\"value\":%d}}",
+                            code == VMCTL_AXIS_X ? "x" : "y", value);
+            break;
+        case VMCTL_EV_REL:
+            pos += snprintf(json + pos, (int)sizeof json - pos,
+                            "{\"type\":\"rel\",\"data\":{\"axis\":\"%s\",\"value\":%d}}",
+                            code == VMCTL_AXIS_X ? "x" : "y", value);
+            break;
+        case VMCTL_EV_BTN:
+            if (code < 0 || code >= BTN_NAMES_LEN) return -1;
+            pos += snprintf(json + pos, (int)sizeof json - pos,
+                            "{\"type\":\"btn\",\"data\":{\"button\":\"%s\",\"down\":%s}}",
+                            btn_names[code], value ? "true" : "false");
+            break;
+        case VMCTL_EV_KEY: {
+            const char* qcode = vmctl_evdev_to_qcode(code);
+            if (!qcode) return -1;
+            pos += snprintf(json + pos, (int)sizeof json - pos,
+                            "{\"type\":\"key\",\"data\":{\"key\":{\"type\":\"qcode\","
+                            "\"data\":\"%s\"},\"down\":%s}}",
+                            qcode, value ? "true" : "false");
+            break;
+        }
+        case VMCTL_EV_SCROLL:
+            pos += snprintf(json + pos, (int)sizeof json - pos,
+                            "{\"type\":\"scl\",\"data\":{\"axis\":\"%s\",\"value\":%g}}",
+                            code == VMCTL_SCROLL_V ? "vertical" : "horizontal", scl);
+            break;
+        default:
+            return -1;
+        }
+    }
+
+    pos += snprintf(json + pos, (int)sizeof json - pos, "]}}");
+
+    char resp[4096];
+    return qmp_exec(v->qmp, json, resp, sizeof resp);
+}
+
+static void qmp_driver_close(vmctl_t* v) {
+    qmp_disconnect(v->qmp);
+}
+
+vmctl_t* vmctl_open_qmp_driver(const vmctl_config* cfg) {
+    qmp_conn* qmp = qmp_connect(cfg->qmp_path);
+    if (!qmp) return NULL;
+
+    vmctl_t* v = calloc(1, sizeof *v);
+    if (!v) {
+        qmp_disconnect(qmp);
+        return NULL;
+    }
+    v->driver     = VMCTL_DRIVER_QMP;
+    v->qmp        = qmp;
+    v->ui_fd_a    = -1;
+    v->ui_fd_b    = -1;
+    v->ptr_mode   = 0;
+    v->ops.send   = qmp_driver_send;
+    v->ops.close  = qmp_driver_close;
+    return v;
+}