[Qemu-devel] [PATCH v4 07/23] qdev: Allow device specification by qtree path for device_del

[Jan Kiszka <jan.kiszka@web.de>]

From: Jan Kiszka <jan.kiszka@siemens.com>

Allow to specify the device to be removed via device_del not only by ID
but also by its full or abbreviated qtree path. For this purpose,
qdev_find is introduced which combines walking the qtree with searching
for device IDs if required.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 hw/qdev.c       |   75 ++++++++++++++++++++++++++++++++++++++++++++-----------
 qemu-monitor.hx |   10 +++---
 2 files changed, 65 insertions(+), 20 deletions(-)

diff --git a/hw/qdev.c b/hw/qdev.c
index ac450cf..2d1d171 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -39,7 +39,7 @@ DeviceInfo *device_info_list;
 
 static BusState *qbus_find_recursive(BusState *bus, const char *name,
                                      const BusInfo *info);
-static BusState *qbus_find(const char *path);
+static BusState *qbus_find(const char *path, bool report_errors);
 
 /* Register a new device type.  */
 void qdev_register(DeviceInfo *info)
@@ -217,7 +217,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
     /* find bus */
     path = qemu_opt_get(opts, "bus");
     if (path != NULL) {
-        bus = qbus_find(path);
+        bus = qbus_find(path, true);
         if (!bus) {
             return NULL;
         }
@@ -475,7 +475,7 @@ static BusState *qbus_find_recursive(BusState *bus, const char *name,
     return NULL;
 }
 
-static DeviceState *qdev_find_recursive(BusState *bus, const char *id)
+static DeviceState *qdev_find_id_recursive(BusState *bus, const char *id)
 {
     DeviceState *dev, *ret;
     BusState *child;
@@ -484,7 +484,7 @@ static DeviceState *qdev_find_recursive(BusState *bus, const char *id)
         if (dev->id && strcmp(dev->id, id) == 0)
             return dev;
         QTAILQ_FOREACH(child, &dev->child_bus, sibling) {
-            ret = qdev_find_recursive(child, id);
+            ret = qdev_find_id_recursive(child, id);
             if (ret) {
                 return ret;
             }
@@ -590,7 +590,7 @@ static DeviceState *qbus_find_dev(BusState *bus, const char *elem)
     return NULL;
 }
 
-static BusState *qbus_find(const char *path)
+static BusState *qbus_find(const char *path, bool report_errors)
 {
     DeviceState *dev;
     BusState *bus = main_system_bus;
@@ -600,7 +600,7 @@ static BusState *qbus_find(const char *path)
     /* search for bus name recursively if path is not absolute */
     if (path[0] != '/') {
         bus = qbus_find_recursive(bus, path, NULL);
-        if (!bus) {
+        if (!bus && report_errors) {
             qerror_report(QERR_BUS_NOT_FOUND, path);
         }
         return bus;
@@ -623,12 +623,16 @@ static BusState *qbus_find(const char *path)
         pos += len;
         dev = qbus_find_dev(bus, elem);
         if (!dev) {
-            qerror_report(QERR_DEVICE_NOT_FOUND, elem);
-            qbus_list_dev(bus);
+            if (report_errors) {
+                qerror_report(QERR_DEVICE_NOT_FOUND, elem);
+                qbus_list_dev(bus);
+            }
             return NULL;
         }
         if (dev->num_child_bus == 0) {
-            qerror_report(QERR_DEVICE_NO_BUS, elem);
+            if (report_errors) {
+                qerror_report(QERR_DEVICE_NO_BUS, elem);
+            }
             return NULL;
         }
 
@@ -644,13 +648,55 @@ static BusState *qbus_find(const char *path)
         pos += len;
         bus = qbus_find_bus(dev, elem);
         if (!bus) {
-            qerror_report(QERR_BUS_NOT_FOUND, elem);
-            qbus_list_bus(dev);
+            if (report_errors) {
+                qerror_report(QERR_BUS_NOT_FOUND, elem);
+                qbus_list_bus(dev);
+            }
             return NULL;
         }
     }
 }
 
+static DeviceState *qdev_find(const char *path)
+{
+    const char *dev_name;
+    DeviceState *dev;
+    char *bus_path;
+    BusState *bus;
+
+    /* search for unique ID recursively if path is not absolute */
+    if (path[0] != '/') {
+        dev = qdev_find_id_recursive(main_system_bus, path);
+        if (!dev) {
+            qerror_report(QERR_DEVICE_NOT_FOUND, path);
+        }
+        return dev;
+    }
+
+    dev_name = strrchr(path, '/') + 1;
+
+    bus_path = qemu_strdup(path);
+    bus_path[dev_name - path] = 0;
+
+    bus = qbus_find(bus_path, false);
+    qemu_free(bus_path);
+    if (!bus) {
+        /* retry with full path to generate correct error message */
+        bus = qbus_find(path, true);
+        if (!bus) {
+            return NULL;
+        }
+        dev_name = "";
+    }
+
+    dev = qbus_find_dev(bus, dev_name);
+    if (!dev) {
+        qerror_report(QERR_DEVICE_NOT_FOUND, dev_name);
+        qbus_list_dev(bus);
+    }
+    return dev;
+}
+
 void qbus_create_inplace(BusState *bus, BusInfo *info,
                          DeviceState *parent, const char *name)
 {
@@ -810,12 +856,11 @@ int do_device_add(Monitor *mon, const QDict *qdict, QObject **ret_data)
 
 int do_device_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
-    const char *id = qdict_get_str(qdict, "id");
+    const char *path = qdict_get_str(qdict, "device");
     DeviceState *dev;
 
-    dev = qdev_find_recursive(main_system_bus, id);
-    if (NULL == dev) {
-        qerror_report(QERR_DEVICE_NOT_FOUND, id);
+    dev = qdev_find(path);
+    if (!dev) {
         return -1;
     }
     return qdev_unplug(dev);
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index 9f62b94..0ea0555 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -703,7 +703,7 @@ EQMP
 
     {
         .name       = "device_del",
-        .args_type  = "id:s",
+        .args_type  = "device:s",
         .params     = "device",
         .help       = "remove device",
         .user_print = monitor_user_noop,
@@ -711,10 +711,10 @@ EQMP
     },
 
 STEXI
-@item device_del @var{id}
+@item device_del @var{device}
 @findex device_del
 
-Remove device @var{id}.
+Remove @var{device}, specified via its qtree path or unique ID.
 ETEXI
 SQMP
 device_del
@@ -724,11 +724,11 @@ Remove a device.
 
 Arguments:
 
-- "id": the device's ID (json-string)
+- "device": the device's qtree path or unique ID (json-string)
 
 Example:
 
--> { "execute": "device_del", "arguments": { "id": "net1" } }
+-> { "execute": "device_del", "arguments": { "device": "net1" } }
 <- { "return": {} }
 
 EQMP
-- 
1.6.0.2