Re: [PATCH v2] selftests/ftrace: Use printf for backslash included command

From: Masami Hiramatsu
Date: Mon May 11 2020 - 09:38:12 EST


Hi Andreas and David,

OK, what about this fix?

On Mon, 11 May 2020 22:36:27 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Since the built-in echo has different behavior in POSIX shell
> (dash) and bash, kprobe_syntax_errors.tc can fail on dash which
> interpret backslash escape automatically.
>
> To fix this issue, we explicitly use printf "%s" (not interpret
> backslash escapes) if the command string can include backslash.
>
> Reported-by: Liu Yiding <yidingx.liu@xxxxxxxxx>
> Suggested-by: Xiao Yang <yangx.jy@xxxxxxxxxxxxxx>
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
> tools/testing/selftests/ftrace/test.d/functions | 8 +++++---
> .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 4 +++-
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> index 61a3c7e2634d..697c77ef2e2b 100644
> --- a/tools/testing/selftests/ftrace/test.d/functions
> +++ b/tools/testing/selftests/ftrace/test.d/functions
> @@ -119,12 +119,14 @@ yield() {
> ping $LOCALHOST -c 1 || sleep .001 || usleep 1 || sleep 1
> }
>
> +# Since probe event command may include backslash, explicitly use printf "%s"
> +# to NOT interpret it.
> ftrace_errlog_check() { # err-prefix command-with-error-pos-by-^ command-file
> - pos=$(echo -n "${2%^*}" | wc -c) # error position
> - command=$(echo "$2" | tr -d ^)
> + pos=$(printf "%s" "${2%^*}" | wc -c) # error position
> + command=$(printf "%s" "$2" | tr -d ^)
> echo "Test command: $command"
> echo > error_log
> - (! echo "$command" >> "$3" ) 2> /dev/null
> + (! printf "%s" "$command" >> "$3" ) 2> /dev/null
> grep "$1: error:" -A 3 error_log
> N=$(tail -n 1 error_log | wc -c)
> # " Command: " and "^\n" => 13
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
> index ef1e9bafb098..eb0f4ab4e070 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
> @@ -91,7 +91,9 @@ esac
> if grep -q "Create/append/" README && grep -q "imm-value" README; then
> echo 'p:kprobes/testevent _do_fork' > kprobe_events
> check_error '^r:kprobes/testevent do_exit' # DIFF_PROBE_TYPE
> -echo 'p:kprobes/testevent _do_fork abcd=\1' > kprobe_events
> +
> +# Explicitly use printf "%s" to not interpret \1
> +printf "%s" 'p:kprobes/testevent _do_fork abcd=\1' > kprobe_events
> check_error 'p:kprobes/testevent _do_fork ^bcd=\1' # DIFF_ARG_TYPE
> check_error 'p:kprobes/testevent _do_fork ^abcd=\1:u8' # DIFF_ARG_TYPE
> check_error 'p:kprobes/testevent _do_fork ^abcd=\"foo"' # DIFF_ARG_TYPE
>


--
Masami Hiramatsu <mhiramat@xxxxxxxxxx>