From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Kicinski Subject: [PATCH net 3/6] tools: bpftool: make error message from getopt_long() JSON-friendly Date: Tue, 28 Nov 2017 17:44:30 -0800 Message-ID: <20171129014434.31694-4-jakub.kicinski@netronome.com> References: <20171129014434.31694-1-jakub.kicinski@netronome.com> Cc: oss-drivers@netronome.com, Quentin Monnet To: netdev@vger.kernel.org Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:43370 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752134AbdK2Bpi (ORCPT ); Tue, 28 Nov 2017 20:45:38 -0500 Received: by mail-pg0-f67.google.com with SMTP id b18so780431pgv.10 for ; Tue, 28 Nov 2017 17:45:38 -0800 (PST) In-Reply-To: <20171129014434.31694-1-jakub.kicinski@netronome.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Quentin Monnet If `getopt_long()` meets an unknown option, it prints its own error message to standard error output. While this does not strictly break JSON output, it is the only case bpftool prints something to standard error output if JSON output is required. All other errors are printed on standard output as JSON objects, so that an external program does not have to parse stderr. This is changed by setting the global variable `opterr` to 0. Furthermore, p_err() is used to reproduce the error message in a more JSON-friendly way, so that users still get to know what the erroneous option is. Signed-off-by: Quentin Monnet Acked-by: Jakub Kicinski --- tools/bpf/bpftool/main.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index d72dd73a4016..d294bc8168be 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -288,6 +288,7 @@ int main(int argc, char **argv) hash_init(prog_table.table); hash_init(map_table.table); + opterr = 0; while ((opt = getopt_long(argc, argv, "Vhpjf", options, NULL)) >= 0) { switch (opt) { @@ -313,7 +314,11 @@ int main(int argc, char **argv) show_pinned = true; break; default: - usage(); + p_err("unrecognized option '%s'", argv[optind - 1]); + if (json_output) + clean_and_exit(-1); + else + usage(); } } -- 2.14.1