Commit 146882a3 authored Nov 28, 2017 by Quentin Monnet Committed by Daniel Borkmann Nov 30, 2017

tools: bpftool: make error message from getopt_long() JSON-friendly



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 <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 7868620a

tools/bpf/bpftool/main.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -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) {
		@@ -313,6 +314,10 @@ int main(int argc, char **argv)
		show_pinned = true;
		break;
		default:
		p_err("unrecognized option '%s'", argv[optind - 1]);
		if (json_output)
		clean_and_exit(-1);
		else
		usage();
		}
		}

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