tools: bpftool: Remove invalid \' json escape

RFC8259 ("The JavaScript Object Notation (JSON) Data Interchange
Format") only specifies \", \\, \/, \b, \f, \n, \r, and \r as valid
two-character escape sequences. This does not include \', which is not
required in JSON because it exclusively uses double quotes as string
separators.

Solidus (/) may be escaped, but does not have to. Only reverse
solidus (\), double quotes ("), and the control characters have to be
escaped. Therefore, with this fix, bpftool correctly supports all valid
two-character escape sequences (but still does not support characters
that require multi-character escape sequences).

Witout this fix, attempting to load a JSON file generated by bpftool
using Python 3.10.6's default json.load() may fail with the error
"Invalid \escape" if the file contains the invalid escaped single
quote (\').

Fixes: b66e907cfee2 ("tools: bpftool: copy JSON writer from iproute2 repository")
Signed-off-by: Luis Gerhorst <gerhorst@cs.fau.de>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20230227150853.16863-1-gerhorst@cs.fau.de

diff --git a/tools/bpf/bpftool/json_writer.c b/tools/bpf/bpftool/json_writer.c
index 7fea83bedf4883961912319e9f001446e8b91767..bca5dd0a59e348e80af9ff0dbfdba5382f6599dd 100644 (file)
--- a/tools/bpf/bpftool/json_writer.c
+++ b/tools/bpf/bpftool/json_writer.c
@@ -80,9 +80,6 @@ static void jsonw_puts(json_writer_t *self, const char *str)
                case '"':
                        fputs("\\\"", self->out);
                        break;
-               case '\'':
-                       fputs("\\\'", self->out);
-                       break;
                default:
                        putc(*str, self->out);
                }