[PATCH v4 02/13] libxl: add generic functions to get and free device list

[Oleksandr Grytsov <al1img@gmail.com>]

From: Oleksandr Grytsov <oleksandr_grytsov@epam.com>

Add libxl__device_list and libxl__device_list_free
functions to handle device list using the device
framework.

Signed-off-by: Oleksandr Grytsov <oleksandr_grytsov@epam.com>
---
 tools/libxl/libxl_device.c   | 66 ++++++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxl_internal.h |  8 ++++++
 2 files changed, 74 insertions(+)

diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 07165f0..f1d4848 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -1991,6 +1991,72 @@ out:
     return rc;
 }
 
+void *libxl__device_list(libxl__gc *gc, const struct libxl_device_type *dt,
+                         uint32_t domid, const char* name, int *num)
+{
+    void *r = NULL;
+    void *list = NULL;
+    void *item = NULL;
+    char *libxl_path;
+    char **dir = NULL;
+    unsigned int ndirs = 0;
+    int rc;
+
+    *num = 0;
+
+    libxl_path = GCSPRINTF("%s/device/%s",
+                           libxl__xs_libxl_path(gc, domid), name);
+
+    dir = libxl__xs_directory(gc, XBT_NULL, libxl_path, &ndirs);
+
+    if (dir && ndirs) {
+        list = libxl__malloc(NOGC, dt->dev_elem_size * ndirs);
+        void *end = (uint8_t *)list + ndirs * dt->dev_elem_size;
+        item = list;
+
+        while (item < end) {
+            dt->init(item);
+
+            if (dt->from_xenstore) {
+                char* device_libxl_path = GCSPRINTF("%s/%s", libxl_path, *dir);
+                rc = dt->from_xenstore(gc, device_libxl_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) {
+            dt->dispose(item);
+            item = (uint8_t*)item - dt->dev_elem_size;
+        }
+        free(list);
+    }
+
+    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 075dfe3..271ac89 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3506,6 +3506,7 @@ struct libxl_device_type {
     int (*dm_needed)(void *, unsigned);
     void (*update_config)(libxl__gc *, void *, void *);
     int (*update_devid)(libxl__gc *, uint32_t, void *);
+    int (*from_xenstore)(libxl__gc *, const char *, libxl_devid, void *);
     int (*set_xenstore_config)(libxl__gc *, uint32_t, void *, flexarray_t *,
                                flexarray_t *, flexarray_t *);
 };
@@ -4386,6 +4387,13 @@ void libxl__device_add_async(libxl__egc *egc, uint32_t domid,
 int libxl__device_add(libxl__gc *gc, uint32_t domid,
                       const struct libxl_device_type *dt, void *type);
 
+/* Caller is responsible for freeing the memory by calling
+ * libxl__device_list_free
+ */
+void* libxl__device_list(libxl__gc *gc, const struct libxl_device_type *dt,
+                         uint32_t domid, const char* name, int *num);
+void libxl__device_list_free(const struct libxl_device_type *dt,
+                             void *list, int num);
 #endif
 
 /*
-- 
2.7.4


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