From: Kees Cook
Sent: 23 June 2021 17:19
On Wed, Jun 23, 2021 at 01:43:04PM +0000, David Laight wrote:
From: Guillaume Tucker
Sent: 23 June 2021 13:40
...
diff --git a/tools/testing/selftests/lkdtm/run.sh b/tools/testing/selftests/lkdtm/run.sh index bb7a1775307b..0f9f22ac004b 100755 --- a/tools/testing/selftests/lkdtm/run.sh +++ b/tools/testing/selftests/lkdtm/run.sh @@ -78,8 +78,9 @@ dmesg > "$DMESG"
# Most shells yell about signals and we're expecting the "cat" process # to usually be killed by the kernel. So we have to run it in a sub-shell -# and silence errors. -($SHELL -c 'cat <(echo '"$test"') >'"$TRIGGER" 2>/dev/null) || true +# to avoid terminating this script. Leave stderr alone, just in case +# something _else_ happens. +(/bin/sh -c '(echo '"$test"') | cat >'"$TRIGGER") || true
I was having trouble parsing that command - and I'm good at shell scripts. I think the extra subshell the 'echo' is in doesn't help. In fact, is either subshell needed? Surely: /bin/sh -c "echo '$test' | cat >$trigger" || true will work just as well?
Ah yeah, and I just tested it to double check, it can be even simpler:
echo "$test" | /bin/sh -c "cat >$TRIGGER" || true
You can probably even do:
echo "$test" | /bin/sh -c cat >$TRIGGER || true
(moving the redirect to the outer shell).
David
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