[PATCH] hid: avoid '\0' in hid debugfs events file
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From: Bruno Prémont on 15 Mar 2010 14:10 When dumping /sys/kernel/debug/hid/$device/events '\0' characters show up (invisible if cat to console but shown by less or while looking at a dump file). These are due to hid_debug_event() adding strlen()+1 bytes to the ring buffer (e.g. including the trailing '\0'). Any roll-over causes a '\0' as well as hid_debug_event() handles the ring buffers with HID_DEBUG_BUFSIZE-1 size while hid_debug_events_read() handles it with full HID_DEBUG_BUFSIZE size. Signed-off-by: Bruno Prémont <bonbons(a)linux-vserver.org> --- Note: The ring buffer overflow case (when tail crosses head) seems to be suboptimal at best. Would there be a good way to mark those cases so reader can know where data got lost. (though this might not be easy keeping the lockless design) diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c index 6abd036..2602695 100644 --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -564,10 +564,10 @@ void hid_debug_event(struct hid_device *hdev, char *buf) struct hid_debug_list *list; list_for_each_entry(list, &hdev->debug_list, node) { - for (i = 0; i <= strlen(buf); i++) - list->hid_debug_buf[(list->tail + i) % (HID_DEBUG_BUFSIZE - 1)] = + for (i = 0; i < strlen(buf); i++) + list->hid_debug_buf[(list->tail + i) % HID_DEBUG_BUFSIZE] = buf[i]; - list->tail = (list->tail + i) % (HID_DEBUG_BUFSIZE - 1); + list->tail = (list->tail + i) % HID_DEBUG_BUFSIZE; } } EXPORT_SYMBOL_GPL(hid_debug_event); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |