hostapd: Global control interface notifications

This commit implements hostapd global control interface notifications
infrastructure. hostapd global control interface clients issue
ATTACH/DETACH commands to register and deregister with hostapd
correspondingly - the same way as for any other hostapd/wpa_supplicant
control interface.

Bug: 24270573

Change-Id: I46da39e8262a446e7779a1adfbcb08b5bfa382d7
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/src/utils/wpa_debug.c b/src/utils/wpa_debug.c
index b7a6dba..3c26301 100644
--- a/src/utils/wpa_debug.c
+++ b/src/utils/wpa_debug.c
@@ -749,6 +749,33 @@
 	bin_clear_free(buf, buflen);
 }
 
+
+void wpa_msg_global_only(void *ctx, int level, const char *fmt, ...)
+{
+	va_list ap;
+	char *buf;
+	int buflen;
+	int len;
+
+	va_start(ap, fmt);
+	buflen = vsnprintf(NULL, 0, fmt, ap) + 1;
+	va_end(ap);
+
+	buf = os_malloc(buflen);
+	if (buf == NULL) {
+		wpa_printf(MSG_ERROR, "%s: Failed to allocate message buffer",
+			   __func__);
+		return;
+	}
+	va_start(ap, fmt);
+	len = vsnprintf(buf, buflen, fmt, ap);
+	va_end(ap);
+	wpa_printf(level, "%s", buf);
+	if (wpa_msg_cb)
+		wpa_msg_cb(ctx, level, WPA_MSG_ONLY_GLOBAL, buf, len);
+	os_free(buf);
+}
+
 #endif /* CONFIG_NO_WPA_MSG */
 
 
diff --git a/src/utils/wpa_debug.h b/src/utils/wpa_debug.h
index 5fdc50e..87bd7fa 100644
--- a/src/utils/wpa_debug.h
+++ b/src/utils/wpa_debug.h
@@ -164,6 +164,7 @@
 #define wpa_msg_global(args...) do { } while (0)
 #define wpa_msg_global_ctrl(args...) do { } while (0)
 #define wpa_msg_no_global(args...) do { } while (0)
+#define wpa_msg_global_only(args...) do { } while (0)
 #define wpa_msg_register_cb(f) do { } while (0)
 #define wpa_msg_register_ifname_cb(f) do { } while (0)
 #else /* CONFIG_NO_WPA_MSG */
@@ -243,10 +244,25 @@
 void wpa_msg_no_global(void *ctx, int level, const char *fmt, ...)
 PRINTF_FORMAT(3, 4);
 
+/**
+ * wpa_msg_global_only - Conditional printf for ctrl_iface monitors
+ * @ctx: Pointer to context data; this is the ctx variable registered
+ *	with struct wpa_driver_ops::init()
+ * @level: priority level (MSG_*) of the message
+ * @fmt: printf format string, followed by optional arguments
+ *
+ * This function is used to print conditional debugging and error messages.
+ * This function is like wpa_msg_global(), but it sends the output only as a
+ * global event.
+ */
+void wpa_msg_global_only(void *ctx, int level, const char *fmt, ...)
+PRINTF_FORMAT(3, 4);
+
 enum wpa_msg_type {
 	WPA_MSG_PER_INTERFACE,
 	WPA_MSG_GLOBAL,
 	WPA_MSG_NO_GLOBAL,
+	WPA_MSG_ONLY_GLOBAL,
 };
 
 typedef void (*wpa_msg_cb_func)(void *ctx, int level, enum wpa_msg_type type,