Re: [PATCH bpf-next 2/3] bpftool: match programs by name

On Fri, 13 Dec 2019 13:40:38 +0100, Paul Chaignon wrote:

quoted

quoted

@@ -176,7 +177,20 @@ prog_parse_fds(int *argc, char ***argv, int *fds)
 		}
 		NEXT_ARGP();
 
-		return prog_fd_by_tag(tag, fds);
+		return prog_fd_by_nametag(tag, fds, true);
+	} else if (is_prefix(**argv, "name")) {
+		char *name;
+
+		NEXT_ARGP();
+
+		name = **argv;
+		if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {  

Is this needed? strncmp will simply never match, is it preferred to
hard error?  

I tried to follow the fail-early pattern of lookups by tag above.  

Right although tag does a scanf and if we didn't scan all letters 
we'd use uninit memory.

I do like that there's a different error message for a longer than
expected name.  Since libbpf silently truncates names, typing a
longer name is not uncommon.

Ugh, I didn't realize libbpf truncates names. Okay, let's keep the
error for now so we can switch to truncation if users complain.