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

[Shuah Khan]

On 5/25/20 3:59 AM, Masami Hiramatsu wrote:
> Hi Shuah,
>
> Could you pick this to kselftest-next?
>
> Thank you,
>
> 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

Applied to

git.kernel.org/pub/scm/linux/kernel/git/shuah/linux kselftest.git/ next
branch for Linux 5.8-rc1

thanks,
-- Shuah