[PATCH v3 03/11] libxl: add generic function to get and free device list

[Oleksandr Grytsov <al1img@gmail.com>]

From: Oleksandr Grytsov <oleksandr_grytsov@epam.com>

Add libxl__device_list, libxl__device_list_free.
Device list is created from libxl xen store entries.
In order to fill libxl device structure from xen store,
the device handling framework extended with from_xenstore callback.
On this callback libxl_device shall be filled with data from
be xen store directory.

Signed-off-by: Oleksandr Grytsov <oleksandr_grytsov@epam.com>
---
 tools/libxl/libxl_device.c   | 76 ++++++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxl_internal.h |  8 +++++
 tools/libxl/libxl_vdispl.c   | 17 ++++++++--
 3 files changed, 98 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 00356af..8bcfa2b 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -1793,6 +1793,82 @@ out:
     return AO_CREATE_FAIL(rc);
 }
 
+void* libxl__device_list(const struct libxl_device_type *dt,
+                         libxl_ctx *ctx, uint32_t domid, int *num)
+{
+    GC_INIT(ctx);
+
+    void *r = NULL;
+    void *list = NULL;
+    void *item = NULL;
+    char *libxl_path;
+    char *be_path;
+    char** dir = NULL;
+    unsigned int ndirs = 0;
+    int rc;
+
+    *num = 0;
+
+    libxl_path = GCSPRINTF("%s/device/%s",
+                           libxl__xs_libxl_path(gc, domid), dt->type);
+
+    dir = libxl__xs_directory(gc, XBT_NULL, libxl_path, &ndirs);
+
+    if (dir && ndirs) {
+        list = malloc(dt->dev_elem_size * ndirs);
+        void *end = (uint8_t*)list + ndirs * dt->dev_elem_size;
+        item = list;
+
+        while(item < end) {
+            be_path = libxl__xs_read(gc, XBT_NULL,
+                                     GCSPRINTF("%s/%s/backend",
+                                     libxl_path, *dir));
+
+            dt->init(item);
+
+            if (dt->from_xenstore)
+            {
+                rc = dt->from_xenstore(gc, be_path, atoi(*dir), item);
+                if (rc) goto out;
+            }
+
+            item = (uint8_t*)item + dt->dev_elem_size;
+            ++dir;
+        }
+    }
+
+    *num = ndirs;
+    r = list;
+    list = NULL;
+
+out:
+
+    if (list) {
+        *num = 0;
+        while(item >= list) {
+            item = (uint8_t*)item - dt->dev_elem_size;
+            dt->dispose(item);
+        }
+        free(list);
+    }
+
+    GC_FREE;
+
+    return r;
+}
+
+void libxl__device_list_free(const struct libxl_device_type *dt,
+                             void *list, int num)
+{
+    int i;
+
+    for (i = 0; i < num; i++) {
+        dt->dispose((uint8_t*)list + i * dt->dev_elem_size);
+    }
+
+    free(list);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index afe6652..c192559 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3484,11 +3484,13 @@ struct libxl_device_type {
     void (*add)(libxl__egc *, libxl__ao *, uint32_t, libxl_domain_config *,
                 libxl__multidev *);
     void *(*list)(libxl_ctx *, uint32_t, int *);
+    void (*init)(void *);
     void (*dispose)(void *);
     int (*compare)(void *, void *);
     void (*merge)(libxl_ctx *, void *, void *);
     int (*dm_needed)(void *, unsigned);
     void (*update_config)(libxl__gc *, void *, void *);
+    int (*from_xenstore)(libxl__gc *, const char *, uint32_t, void *);
 };
 
 #define DEFINE_DEVICE_TYPE_STRUCT_X(name, sname, ...)                          \
@@ -3500,6 +3502,7 @@ struct libxl_device_type {
         .add           = libxl__add_ ## name ## s,                             \
         .list          = (void *(*)(libxl_ctx *, uint32_t, int *))             \
                          libxl_device_ ## sname ## _list,                      \
+        .init          = (void (*)(void *))libxl_device_ ## sname ## _init,    \
         .dispose       = (void (*)(void *))libxl_device_ ## sname ## _dispose, \
         .compare       = (int (*)(void *, void *))                             \
                          libxl_device_ ## sname ## _compare,                   \
@@ -3534,6 +3537,7 @@ extern const struct libxl_device_type libxl__vtpm_devtype;
 extern const struct libxl_device_type libxl__usbctrl_devtype;
 extern const struct libxl_device_type libxl__usbdev_devtype;
 extern const struct libxl_device_type libxl__pcidev_devtype;
+extern const struct libxl_device_type libxl__vdispl_devtype;
 
 extern const struct libxl_device_type *device_type_tbl[];
 
@@ -4350,6 +4354,10 @@ static inline bool libxl__acpi_defbool_val(const libxl_domain_build_info *b_info
     return libxl_defbool_val(b_info->acpi) &&
            libxl_defbool_val(b_info->u.hvm.acpi);
 }
+void* libxl__device_list(const struct libxl_device_type *dt,
+                         libxl_ctx *ctx, uint32_t domid, int *num);
+void libxl__device_list_free(const struct libxl_device_type *dt,
+                             void *list, int num);
 #endif
 
 /*
diff --git a/tools/libxl/libxl_vdispl.c b/tools/libxl/libxl_vdispl.c
index 2658e25..a628adc 100644
--- a/tools/libxl/libxl_vdispl.c
+++ b/tools/libxl/libxl_vdispl.c
@@ -21,6 +21,15 @@ static int libxl__device_from_vdispl(libxl__gc *gc, uint32_t domid,
    return 0;
 }
 
+static int libxl__from_xenstore_vdispl(libxl__gc *gc, const char *be_path,
+                                       uint32_t devid,
+                                       libxl_device_vdispl *vdispl)
+{
+    vdispl->devid = devid;
+
+    return libxl__backendpath_parse_domid(gc, be_path, &vdispl->backend_domid);
+}
+
 static void libxl__update_config_vdispl(libxl__gc *gc,
                                         libxl_device_vdispl *dst,
                                         libxl_device_vdispl *src)
@@ -44,12 +53,12 @@ static void libxl__device_vdispl_add(libxl__egc *egc, uint32_t domid,
 libxl_device_vdispl *libxl_device_vdispl_list(libxl_ctx *ctx, uint32_t domid,
                                               int *num)
 {
-    return NULL;
+    return libxl__device_list(&libxl__vdispl_devtype, ctx, domid, num);
 }
 
 void libxl_device_vdispl_list_free(libxl_device_vdispl* list, int num)
 {
-
+    libxl__device_list_free(&libxl__vdispl_devtype, list, num);
 }
 
 int libxl_device_vdispl_getinfo(libxl_ctx *ctx, uint32_t domid,
@@ -65,7 +74,9 @@ LIBXL_DEFINE_DEVICE_REMOVE(vdispl)
 
 DEFINE_DEVICE_TYPE_STRUCT(vdispl,
     .update_config = (void (*)(libxl__gc *, void *, void *))
-                     libxl__update_config_vdispl
+                     libxl__update_config_vdispl,
+    .from_xenstore = (int (*)(libxl__gc *, const char *, uint32_t, void *))
+                     libxl__from_xenstore_vdispl
 );
 
 /*
-- 
2.7.4


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