[hackers] [sbase] Check explicit length in od(1) || FRIGN

[git]

commit 0d6d1dc02f6ade56a60337b77d279468d24ba69b
Author:     FRIGN <d...@frign.de>
AuthorDate: Tue Sep 29 23:14:59 2015 +0200
Commit:     sin <s...@2f30.org>
CommitDate: Wed Sep 30 19:44:10 2015 +0100

    Check explicit length in od(1)
    
    If you pass an empty string, the null-char will always match
    with strchr()!

diff --git a/od.c b/od.c
index b24a279..407f550 100644
--- a/od.c
+++ b/od.c
@@ -108,13 +108,13 @@ main(int argc, char *argv[])
        ARGBEGIN {
        case 'A':
                s = EARGF(usage());
-               if (strlen(s) > 1 || !strchr("doxn", s[0]))
+               if (strlen(s) != 1 || !strchr("doxn", s[0]))
                        usage();
                radix = s[0];
                break;
        case 't':
                s = EARGF(usage());
-               if (strlen(s) > 1 || !strchr("acdoux", s[0]))
+               if (strlen(s) != 1 || !strchr("acdoux", s[0]))
                        usage();
                type = s[0];
                break;