Check os_snprintf() result more consistently - maximum length

This adds verification of os_snprintf() result against the maximum
buffer length. These changes were done automatically with spatch
using the following semantic patch:

@@
expression E1,E2,E3;
statement S1;
@@

  E1 = os_snprintf(E2, E3, ...);
- if (\( E1 < 0 \| E1 <= 0 \))
+ if (os_snprintf_error(E3, E1))
(
  S1
|
{ ... }
)

Signed-off-by: Jouni Malinen <j@w1.fi>

src/drivers/driver_nl80211.c

@@ -7972,7 +7972,7 @@ static int linux_write_system_file(const char *path, unsigned int val)
 	int fd, len;
 
 	len = os_snprintf(buf, sizeof(buf), "%u\n", val);
-	if (len < 0)
+	if (os_snprintf_error(sizeof(buf), len))
 		return -1;
 
 	fd = open(path, O_WRONLY);

wpa_supplicant/dbus/dbus_new_handlers.c

@@ -247,7 +247,7 @@ dbus_bool_t set_network_properties(struct wpa_supplicant *wpa_s,
 
 			ret = os_snprintf(value, size, "%u",
 					  entry.uint32_value);
-			if (ret <= 0)
+			if (os_snprintf_error(size, ret))
 				goto error;
 		} else if (entry.type == DBUS_TYPE_INT32) {
 			value = os_zalloc(size);
@@ -256,7 +256,7 @@ dbus_bool_t set_network_properties(struct wpa_supplicant *wpa_s,
 
 			ret = os_snprintf(value, size, "%d",
 					  entry.int32_value);
-			if (ret <= 0)
+			if (os_snprintf_error(size, ret))
 				goto error;
 		} else
 			goto error;

wpa_supplicant/dbus/dbus_old_handlers.c

@@ -981,7 +981,7 @@ DBusMessage * wpas_dbus_iface_set_network(DBusMessage *message,
 				goto error;
 			ret = os_snprintf(value, size, "%u",
 					  entry.uint32_value);
-			if (ret <= 0)
+			if (os_snprintf_error(size, ret))
 				goto error;
 		} else if (entry.type == DBUS_TYPE_INT32) {
 			value = os_zalloc(size);
@@ -989,7 +989,7 @@ DBusMessage * wpas_dbus_iface_set_network(DBusMessage *message,
 				goto error;
 			ret = os_snprintf(value, size, "%d",
 					  entry.int32_value);
-			if (ret <= 0)
+			if (os_snprintf_error(size, ret))
 				goto error;
 		} else
 			goto error;