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| author | Peter Maydell <peter.maydell@linaro.org> | 2026-03-17 09:48:05 +0000 |
|---|---|---|
| committer | Kostiantyn Kostiuk <kkostiuk@redhat.com> | 2026-03-27 19:55:01 +0200 |
| commit | 65b9f4791c24b09814ae51135e8dad283faed348 (patch) | |
| tree | 9ae84eca0d844967570c49a136a2af8e3be07e12 /scripts | |
| parent | b5abb655fab6145ff3728d4bdaea3648468590fc (diff) | |
| download | qemu-65b9f4791c24b09814ae51135e8dad283faed348.tar.gz qemu-65b9f4791c24b09814ae51135e8dad283faed348.zip | |
scripts/qemu-guest-agent/fsfreeze-hook: Avoid use of PIPESTATUS
PIPESTATUS is a bash-specific construct, and this script is supposed
to be POSIX shell. We only use it in one place, to capture the exit
status of a command whose output we are piping to 'logger'.
Replace the PIPESTATUS usage with the trick described in
https://unix.stackexchange.com/questions/14270/get-exit-status-of-process-thats-piped-to-another/70675#70675
which uses a command-group to capture the status of the
first process in the pipeline.
Cc: qemu-stable@nongnu.org
Fixes: 85978dfb6b1c133 ("qemu-ga: Optimize freeze-hook script logic of logging error")
Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3339
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Kostiantyn Kostiuk <kkostiuk@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20260317094806.1944053-3-peter.maydell@linaro.org
Signed-off-by: Kostiantyn Kostiuk <kkostiuk@redhat.com>
Diffstat (limited to 'scripts')
| -rwxr-xr-x | scripts/qemu-guest-agent/fsfreeze-hook | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/scripts/qemu-guest-agent/fsfreeze-hook b/scripts/qemu-guest-agent/fsfreeze-hook index 6e2d7588af..21eb5c5145 100755 --- a/scripts/qemu-guest-agent/fsfreeze-hook +++ b/scripts/qemu-guest-agent/fsfreeze-hook @@ -47,8 +47,23 @@ for file in "$FSFREEZE_D"/* ; do "$file" "$@" >>"$LOGFILE" 2>&1 STATUS=$? else - "$file" "$@" 2>&1 | logger -t qemu-ga-freeze-hook - STATUS=${PIPESTATUS[0]} + # We want to pipe the output of $file through 'logger' and also + # capture its exit status. Since we are a POSIX script we can't + # use PIPESTATUS, so instead this is a trick borrowed from + # https://unix.stackexchange.com/questions/14270/get-exit-status-of-process-thats-piped-to-another/70675#70675 + # which uses command-groups and redirection to get the exit status. + # This is equivalent to + # "$file" "$@" 2>&1 | logger -t qemu-ga-freeze-hook + # plus setting the exit status of the pipe to the exit + # status of the first command rather than the last one. + { { { { + "$file" "$@" 2>&1 3>&- 4>&- + echo $? >&3 + } | logger -t qemu-ga-freeze-hook >&4 + } 3>&1 + } | { read -r xs ; exit "$xs"; } + } 4>&1 + STATUS=$? fi if [ "$STATUS" -ne 0 ]; then |