audit, db: add etc/apk/protected_files.d and new audit features

fixes #607.

audit is now mostly rewritten for the new functionality. And
has new features like --check-permissions, --recursive and
--packages.

$ROOT/etc/apk/protected_files.d/*.list can now contain additional
protected paths, one path per line:

+etc
@etc/init.d
-tmp

+ will include the directory as protected configuration directory.
@ considers the directory protected, but will backup only symlinks.
- removes any protection

lbu should be modified to put include and exclude paths in
etc/apk/protected_files.d/lbu.list. Additionally, some packages
might provide their own listings.

E.g. ssh might want to provide ssh.list with something like:
+root/.ssh
+home/*/.ssh

1 files changed, 5 insertions, 2 deletions

diff --git a/src/io.c b/src/io.c
index 71ccfda..0ae46f0 100644
--- a/src/io.c
+++ b/src/io.c
@@ -560,8 +560,11 @@ int apk_dir_foreach_file(int dirfd, apk_dir_file_cb cb, void *ctx)
 	rewinddir(dir);
 
 	while ((de = readdir(dir)) != NULL) {
-		if (de->d_name[0] == '.')
-			continue;
+		if (de->d_name[0] == '.') {
+			if (de->d_name[1] == 0 ||
+			    (de->d_name[1] == '.' && de->d_name[2] == 0))
+				continue;
+		}
 		cb(ctx, dirfd, de->d_name);
 	}
 	closedir(dir);