log: Add filter flag to deny on match
Without this flag, log filters can only explicitly accept messages.
Allowing denial makes it easier to filter certain subsystems. Unlike
allow-ing filters, deny-ing filters are added to the beginning of the
filter list. This should do the Right Thing most of the time, but it's
less-universal than allowing filters to be inserted anywhere. If this
becomes a problem, then perhaps log_filter_add* should take a filter number
to insert before/after.
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/log.c b/common/log.c
index b7b144f..c1b6b61 100644
--- a/common/log.c
+++ b/common/log.c
@@ -170,7 +170,11 @@
if (filt->file_list &&
!log_has_file(filt->file_list, rec->file))
continue;
- return true;
+
+ if (filt->flags & LOGFF_DENY)
+ return false;
+ else
+ return true;
}
return false;
@@ -284,7 +288,11 @@
}
}
filt->filter_num = ldev->next_filter_num++;
- list_add_tail(&filt->sibling_node, &ldev->filter_head);
+ /* Add deny filters to the beginning of the list */
+ if (flags & LOGFF_DENY)
+ list_add(&filt->sibling_node, &ldev->filter_head);
+ else
+ list_add_tail(&filt->sibling_node, &ldev->filter_head);
return filt->filter_num;
diff --git a/include/log.h b/include/log.h
index ee94f14..05833f2 100644
--- a/include/log.h
+++ b/include/log.h
@@ -361,13 +361,22 @@
LOGF_MAX_CATEGORIES = 5, /* maximum categories per filter */
};
+/**
+ * enum log_filter_flags - Flags which modify a filter
+ */
enum log_filter_flags {
- LOGFF_HAS_CAT = 1 << 0, /* Filter has a category list */
+ /** @LOGFF_HAS_CAT: Filter has a category list */
+ LOGFF_HAS_CAT = 1 << 0,
+ /** @LOGFF_DENY: Filter denies matching messages */
+ LOGFF_DENY = 1 << 1,
};
/**
* struct log_filter - criterial to filter out log messages
*
+ * If a message matches all criteria, then it is allowed. If LOGFF_DENY is set,
+ * then it is denied instead.
+ *
* @filter_num: Sequence number of this filter. This is returned when adding a
* new filter, and must be provided when removing a previously added
* filter.