Re: [PATCH v3 19/91] tests/tcg/meson.build: add wrapper record_replay

["Alex Bennée" <alex.bennee@linaro.org>]

Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> writes:

> On 7/9/2026 8:03 AM, Pierrick Bouvier wrote:
>> On 7/9/2026 7:52 AM, Alex Bennée wrote:
>>> Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> writes:
>>>
>>>> Runs a record and replay test, and make sure the output produced by
>>>> both runs is the same.
>>>>
>>>> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
>>>> ---
>>>>  tests/tcg/meson.build              |  1 +
>>>>  tests/tcg/scripts/record_replay.sh | 16 ++++++++++++++++
>>>>  2 files changed, 17 insertions(+)
>>>>  create mode 100755 tests/tcg/scripts/record_replay.sh
>>>>
>>>> diff --git a/tests/tcg/meson.build b/tests/tcg/meson.build
>>>> index 30178df0f7a..e610ce30f40 100644
>>>> --- a/tests/tcg/meson.build
>>>> +++ b/tests/tcg/meson.build
>>>> @@ -7,6 +7,7 @@ if config_host.has_key('GDB')
>>>>  endif
>>>>  gdb = find_program(gdb_progs, required: false)
>>>>  prog_gdb_test = find_program('../guest-debug/run-test.py')
>>>> +prog_record_replay = find_program('./scripts/record_replay.sh')
>>>>  prog_run_and_diff = find_program('./scripts/run_and_diff.sh')
>>>>  prog_run_with_input = find_program('./scripts/run_with_input.sh')
>>>>  prog_run_and_check_forbidden_output = find_program(
>>>> diff --git a/tests/tcg/scripts/record_replay.sh b/tests/tcg/scripts/record_replay.sh
>>>> new file mode 100755
>>>> index 00000000000..57775a2d4c1
>>>> --- /dev/null
>>>> +++ b/tests/tcg/scripts/record_replay.sh
>>>> @@ -0,0 +1,16 @@
>>>> +#!/usr/bin/env bash
>>>
>>> While at it is there any reason this couldn't be plain POSIX shell. I
>>> don't think we explicitly require bash although its super likely to be
>>> on most systems. configure is all POSIX shell.
>>>
>> 
>> The main reason for me to use bash is that it supports set -uo pipefail
>> in combination with set -e.
>> 
>> Which produces:
>> - exit if a variable is undefined
>> - exit if any command in a pipe sequence fails
>> Without this, script shells are pretty much house of cards waiting to
>> collapse on any corner case.
>> 
>> bash is available out of the box at least on macos, msys2, and I expect,
>> every single linux distro out there. Not sure about bsds though.
>> 
>> If that's such a big issue, I can port the scripts to sh.
>>
>
> Interestingly, QEMU main Makefile makes bash a defacto requirement,
> since it uses it for every single command to run. The reason is... to
> use -o pipefail.
>
> https://gitlab.com/qemu-project/qemu/-/blob/master/Makefile?ref_type=heads#L17
>

Well it looks like I misremembered as we list bash as a dependency in
qemu-minimal:

  packages:
   - bash

so I drop my objection.


>>>> +# SPDX-License-Identifier: GPL-2.0-or-later
>>>> +
>>>> +set -euo pipefail
>>>> +
>>>> +if [ $# -lt 2 ]; then
>>>> +    echo "record_replay: qemu_bin [args]..." 1>&2
>>>> +    exit 1
>>>> +fi
>>>> +qemu="$1";shift
>>>> +tmp=$(mktemp -d)
>>>> +trap "rm -rf $tmp" EXIT
>>>> +set -x
>>>> +$qemu -icount shift=5,rr=record,rrfile=$tmp/rr.bin "$@" |& tee $tmp/record
>>>> +$qemu -icount shift=5,rr=replay,rrfile=$tmp/rr.bin "$@" |& tee $tmp/replay
>>>> +diff $tmp/record $tmp/replay
>>>
>> 

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro