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-rw-r--r--include/qemu-common.h8
-rw-r--r--util/id.c37
2 files changed, 45 insertions, 0 deletions
diff --git a/include/qemu-common.h b/include/qemu-common.h
index 0bd212b..2f74540 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -246,6 +246,14 @@ int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end,
#define STR_OR_NULL(str) ((str) ? (str) : "null")
/* id.c */
+
+typedef enum IdSubSystems {
+ ID_QDEV,
+ ID_BLOCK,
+ ID_MAX /* last element, used as array size */
+} IdSubSystems;
+
+char *id_generate(IdSubSystems id);
bool id_wellformed(const char *id);
/* path.c */
diff --git a/util/id.c b/util/id.c
index 09b22fb..bcc64d8 100644
--- a/util/id.c
+++ b/util/id.c
@@ -26,3 +26,40 @@ bool id_wellformed(const char *id)
}
return true;
}
+
+#define ID_SPECIAL_CHAR '#'
+
+static const char *const id_subsys_str[] = {
+ [ID_QDEV] = "qdev",
+ [ID_BLOCK] = "block",
+};
+
+/*
+ * Generates an ID of the form PREFIX SUBSYSTEM NUMBER
+ * where:
+ *
+ * - PREFIX is the reserved character '#'
+ * - SUBSYSTEM identifies the subsystem creating the ID
+ * - NUMBER is a decimal number unique within SUBSYSTEM.
+ *
+ * Example: "#block146"
+ *
+ * Note that these IDs do not satisfy id_wellformed().
+ *
+ * The caller is responsible for freeing the returned string with g_free()
+ */
+char *id_generate(IdSubSystems id)
+{
+ static uint64_t id_counters[ID_MAX];
+ uint32_t rnd;
+
+ assert(id < ID_MAX);
+ assert(id_subsys_str[id]);
+
+ rnd = g_random_int_range(0, 100);
+
+ return g_strdup_printf("%c%s%" PRIu64 "%02" PRId32, ID_SPECIAL_CHAR,
+ id_subsys_str[id],
+ id_counters[id]++,
+ rnd);
+}
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