[PATCH v4 09/10] libxl: call hotplug scripts for nic devices from libxl

[Roger Pau Monne <roger.pau@citrix.com>]

Since most of the needed work is already done in previous patches,
this patch only contains the necessary code to call hotplug scripts
for nic devices, that should be called when the device is added or
removed from a guest.

Changes since v2:

 * Change libxl__nic_type to return the value in a parameter passed by
   the caller.

 * Rename vif_execute to num_exec, to represent the number of times
   hotplug scripts have been called for that device.

Changes since v1:

 * Move event code to libxl_device.c (as in previous patch).

Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
---
 tools/hotplug/Linux/xen-backend.rules |    6 +-
 tools/libxl/libxl_device.c            |   46 ++++++++++++++++-
 tools/libxl/libxl_internal.h          |    6 ++-
 tools/libxl/libxl_linux.c             |   92 +++++++++++++++++++++++++++++++-
 4 files changed, 142 insertions(+), 8 deletions(-)

diff --git a/tools/hotplug/Linux/xen-backend.rules b/tools/hotplug/Linux/xen-backend.rules
index d55ff11..c591a3f 100644
--- a/tools/hotplug/Linux/xen-backend.rules
+++ b/tools/hotplug/Linux/xen-backend.rules
@@ -2,8 +2,8 @@ SUBSYSTEM=="xen-backend", KERNEL=="tap*", ENV{UDEV_CALL}="1", RUN+="/etc/xen/scr
 SUBSYSTEM=="xen-backend", KERNEL=="vbd*", ENV{UDEV_CALL}="1", RUN+="/etc/xen/scripts/block $env{ACTION}"
 SUBSYSTEM=="xen-backend", KERNEL=="vtpm*", RUN+="/etc/xen/scripts/vtpm $env{ACTION}"
 SUBSYSTEM=="xen-backend", KERNEL=="vif2-*", RUN+="/etc/xen/scripts/vif2 $env{ACTION}"
-SUBSYSTEM=="xen-backend", KERNEL=="vif-*", ACTION=="online", RUN+="/etc/xen/scripts/vif-setup online type_if=vif"
-SUBSYSTEM=="xen-backend", KERNEL=="vif-*", ACTION=="offline", RUN+="/etc/xen/scripts/vif-setup offline type_if=vif"
+SUBSYSTEM=="xen-backend", KERNEL=="vif-*", ENV{UDEV_CALL}="1", ACTION=="online", RUN+="/etc/xen/scripts/vif-setup online type_if=vif"
+SUBSYSTEM=="xen-backend", KERNEL=="vif-*", ENV{UDEV_CALL}="1", ACTION=="offline", RUN+="/etc/xen/scripts/vif-setup offline type_if=vif"
 SUBSYSTEM=="xen-backend", KERNEL=="vscsi*", RUN+="/etc/xen/scripts/vscsi $env{ACTION}"
 SUBSYSTEM=="xen-backend", ACTION=="remove", ENV{UDEV_CALL}="1", RUN+="/etc/xen/scripts/xen-hotplug-cleanup"
 KERNEL=="evtchn", NAME="xen/%k"
@@ -13,4 +13,4 @@ KERNEL=="blktap-control", NAME="xen/blktap-2/control", MODE="0600"
 KERNEL=="gntdev", NAME="xen/%k", MODE="0600"
 KERNEL=="pci_iomul", NAME="xen/%k", MODE="0600"
 KERNEL=="tapdev[a-z]*", NAME="xen/blktap-2/tapdev%m", MODE="0600"
-SUBSYSTEM=="net", KERNEL=="vif*-emu", ACTION=="add", RUN+="/etc/xen/scripts/vif-setup $env{ACTION} type_if=tap"
+SUBSYSTEM=="net", KERNEL=="vif*-emu", ACTION=="add", ENV{UDEV_CALL}="1", RUN+="/etc/xen/scripts/vif-setup $env{ACTION} type_if=tap"
diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 8e1ec0f..5c840f8 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -100,6 +100,29 @@ out:
     return numdevs;
 }
 
+int libxl__nic_type(libxl__gc *gc, libxl__device *dev, libxl_nic_type *nictype)
+{
+    char *snictype, *be_path;
+    int rc = 0;
+
+    be_path = libxl__device_backend_path(gc, dev);
+    snictype = libxl__xs_read(gc, XBT_NULL,
+                              GCSPRINTF("%s/%s", be_path, "type"));
+    if (!snictype) {
+        LOGE(ERROR, "unable to read nictype from %s", be_path);
+        rc = ERROR_FAIL;
+        goto out;
+    }
+    rc = libxl_nic_type_from_string(snictype, nictype);
+    if (rc) {
+        LOGE(ERROR, "unable to parse nictype from %s", be_path);
+        goto out;
+    }
+
+out:
+    return rc;
+}
+
 int libxl__device_generic_add(libxl__gc *gc, libxl__device *device,
                              char **bents, char **fents)
 {
@@ -723,7 +746,8 @@ static void device_hotplug(libxl__egc *egc, libxl__ao_device *aodev)
     /* Check if we have to execute hotplug scripts for this device
      * and return the necessary args/env vars for execution */
     hotplug = libxl__get_hotplug_script_info(gc, aodev->dev, &args, &env,
-                                             aodev->action);
+                                             aodev->action,
+                                             aodev->num_exec);
     switch (hotplug) {
     case 0:
         /* no hotplug script to execute */
@@ -789,6 +813,8 @@ static void device_hotplug_fork_cb(libxl__egc *egc, libxl__ev_child *child,
 {
     libxl__ao_device *aodev = CONTAINER_OF(child, *aodev, child);
     STATE_AO_GC(aodev->ao);
+    libxl_nic_type nictype;
+    int rc;
 
     libxl__ev_time_deregister(gc, &aodev->ev);
 
@@ -797,7 +823,25 @@ static void device_hotplug_fork_cb(libxl__egc *egc, libxl__ev_child *child,
                                                      : LIBXL__LOG_WARNING,
                                       aodev->what, pid, status);
         aodev->rc = ERROR_FAIL;
+        goto out;
     }
+
+    if (aodev->dev->backend_kind == LIBXL__DEVICE_KIND_VIF &&
+        aodev->num_exec == 0) {
+        rc = libxl__nic_type(gc, aodev->dev, &nictype);
+        if (rc) {
+            LOG(ERROR, "unable to get type of nic device");
+            aodev->rc = rc;
+            goto out;
+        }
+        if (nictype == LIBXL_NIC_TYPE_IOEMU) {
+            aodev->num_exec++;
+            device_hotplug(egc, aodev);
+            return;
+        }
+    }
+
+out:
     aodev->callback(egc, aodev);
 }
 
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index da5b02b..766f1f3 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -803,6 +803,8 @@ _hidden int libxl__parse_backend_path(libxl__gc *gc, const char *path,
                                       libxl__device *dev);
 _hidden int libxl__device_destroy(libxl__gc *gc, libxl__device *dev);
 _hidden int libxl__wait_for_backend(libxl__gc *gc, char *be_path, char *state);
+_hidden int libxl__nic_type(libxl__gc *gc, libxl__device *dev,
+                            libxl_nic_type *nictype);
 
 /*
  * For each aggregate type which can be used as an input we provide:
@@ -1818,6 +1820,7 @@ struct libxl__ao_device {
     /* device hotplug execution */
     pid_t pid;
     char *what;
+    int num_exec;
     libxl__ev_time ev;
     libxl__ev_child child;
 };
@@ -1860,7 +1863,8 @@ _hidden void libxl__initiate_device_remove(libxl__egc *egc,
  */
 _hidden int libxl__get_hotplug_script_info(libxl__gc *gc, libxl__device *dev,
                                            char ***args, char ***env,
-                                           libxl__device_action action);
+                                           libxl__device_action action,
+                                           int num_exec);
 
 /*----- Domain destruction -----*/
 
diff --git a/tools/libxl/libxl_linux.c b/tools/libxl/libxl_linux.c
index 98cd25f..e1e2abe 100644
--- a/tools/libxl/libxl_linux.c
+++ b/tools/libxl/libxl_linux.c
@@ -34,7 +34,8 @@ static char **get_hotplug_env(libxl__gc *gc, libxl__device *dev)
     char *script;
     const char *type = libxl__device_kind_to_string(dev->backend_kind);
     char **env;
-    int nr = 0, arraysize = 9;
+    int nr = 0, arraysize = 13;
+    libxl_nic_type nictype;
 
     script = libxl__xs_read(gc, XBT_NULL,
                             GCSPRINTF("%s/%s", be_path, "script"));
@@ -52,14 +53,94 @@ static char **get_hotplug_env(libxl__gc *gc, libxl__device *dev)
     env[nr++] = GCSPRINTF("backend/%s/%u/%d", type, dev->domid, dev->devid);
     env[nr++] = "XENBUS_BASE_PATH";
     env[nr++] = "backend";
+    if (dev->backend_kind == LIBXL__DEVICE_KIND_VIF) {
+        if (libxl__nic_type(gc, dev, &nictype)) {
+            LOG(ERROR, "unable to get nictype");
+            return NULL;
+        }
+        switch (nictype) {
+        case LIBXL_NIC_TYPE_IOEMU:
+            env[nr++] = "INTERFACE";
+            env[nr++] = libxl__strdup(gc, libxl__device_nic_devname(gc,
+                                                      dev->domid, dev->devid,
+                                                      LIBXL_NIC_TYPE_IOEMU));
+        case LIBXL_NIC_TYPE_VIF:
+            env[nr++] = "vif";
+            env[nr++] = libxl__strdup(gc, libxl__device_nic_devname(gc,
+                                                      dev->domid, dev->devid,
+                                                      LIBXL_NIC_TYPE_VIF));
+            break;
+        default:
+            return NULL;
+        }
+    }
+
     env[nr++] = NULL;
-    assert(nr == arraysize);
+    assert(nr <= arraysize);
 
     return env;
 }
 
 /* Hotplug scripts caller functions */
 
+static int libxl__hotplug_nic(libxl__gc *gc, libxl__device *dev,
+                               char ***args, char ***env,
+                               libxl__device_action action, int num_exec)
+{
+    char *be_path = libxl__device_backend_path(gc, dev);
+    char *script;
+    int nr = 0, rc = 0, arraysize = 4;
+    libxl_nic_type nictype;
+
+    script = libxl__xs_read(gc, XBT_NULL, GCSPRINTF("%s/%s", be_path,
+                                                             "script"));
+    if (!script) {
+        LOGE(ERROR, "unable to read script from %s", be_path);
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    rc = libxl__nic_type(gc, dev, &nictype);
+    if (rc) {
+        LOG(ERROR, "error when fetching nic type");
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    *env = get_hotplug_env(gc, dev);
+    if (!env) {
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    GCNEW_ARRAY(*args, arraysize);
+    (*args)[nr++] = script;
+
+    switch (nictype) {
+    case LIBXL_NIC_TYPE_IOEMU:
+        if (num_exec == 0) goto execute_vif;
+        (*args)[nr++] = action == DEVICE_CONNECT ? "add" : "remove";
+        (*args)[nr++] = libxl__strdup(gc, "type_if=tap");
+        (*args)[nr++] = NULL;
+        break;
+    case LIBXL_NIC_TYPE_VIF:
+execute_vif:
+        (*args)[nr++] = action == DEVICE_CONNECT ? "online" : "offline";
+        (*args)[nr++] = libxl__strdup(gc, "type_if=vif");
+        (*args)[nr++] = NULL;
+        break;
+    default:
+        /* Unknown network type */
+        LOG(ERROR, "unknown network card type %s", be_path);
+        return 0;
+    }
+    assert(nr == arraysize);
+    rc = 0;
+
+out:
+    return rc;
+}
+
 static int libxl__hotplug_disk(libxl__gc *gc, libxl__device *dev,
                                char ***args, char ***env,
                                libxl__device_action action)
@@ -96,7 +177,8 @@ error:
 
 int libxl__get_hotplug_script_info(libxl__gc *gc, libxl__device *dev,
                                    char ***args, char ***env,
-                                   libxl__device_action action)
+                                   libxl__device_action action,
+                                   int num_exec)
 {
     char *disable_udev = libxl__xs_read(gc, XBT_NULL, DISABLE_UDEV_PATH);
     int rc;
@@ -112,6 +194,10 @@ int libxl__get_hotplug_script_info(libxl__gc *gc, libxl__device *dev,
         rc = libxl__hotplug_disk(gc, dev, args, env, action);
         if (!rc) rc = 1;
         break;
+    case LIBXL__DEVICE_KIND_VIF:
+        rc = libxl__hotplug_nic(gc, dev, args, env, action, num_exec);
+        if (!rc) rc = 1;
+        break;
     default:
         /* If no need to execute any hotplug scripts,
          * call the callback manually
-- 
1.7.7.5 (Apple Git-26)