context_run() has a race condition if two commands are run in close
proximity (generally involving at least one in the background). Because we
always use the same name for the temporary fifo files, if another command
is issued while the fifos for the first still exist, mkfifo will fail,
typically causing the entire test script to jam.
Create unique names for the temporary fifos to avoid this problem.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
test/lib/context | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/test/lib/context b/test/lib/context
index d9d8260..09cad89 100644
--- a/test/lib/context
+++ b/test/lib/context
@@ -93,8 +93,8 @@ context_run() {
__name="$1"
__log="${LOGDIR}/context_${__name}.log"
__enter="${STATESETUP}/context_${__name}.enter"
- __stdout="${STATESETUP}/context_${__name}.stdout"
- __stderr="${STATESETUP}/context_${__name}.stderr"
+ __stdout="$(mktemp -u
"${STATESETUP}/context_${__name}.stdout.XXXXXXXX")"
+ __stderr="$(mktemp -u
"${STATESETUP}/context_${__name}.stderr.XXXXXXXX")"
shift
echo "$*" >> "${__log}"
mkfifo "${__stdout}" "${__stderr}"
--
2.39.2
On Wed, 5 Apr 2023 11:56:42 +1000 David Gibson <david(a)gibson.dropbear.id.au> wrote:context_run() has a race condition if two commands are run in close proximity (generally involving at least one in the background). Because we always use the same name for the temporary fifo files, if another command is issued while the fifos for the first still exist, mkfifo will fail, typically causing the entire test script to jam. Create unique names for the temporary fifos to avoid this problem. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- test/lib/context | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/test/lib/context b/test/lib/context index d9d8260..09cad89 100644 --- a/test/lib/context +++ b/test/lib/context @@ -93,8 +93,8 @@ context_run() { __name="$1" __log="${LOGDIR}/context_${__name}.log" __enter="${STATESETUP}/context_${__name}.enter" - __stdout="${STATESETUP}/context_${__name}.stdout" - __stderr="${STATESETUP}/context_${__name}.stderr" + __stdout="$(mktemp -u "${STATESETUP}/context_${__name}.stdout.XXXXXXXX")" + __stderr="$(mktemp -u "${STATESETUP}/context_${__name}.stderr.XXXXXXXX")"In practice, this is never going to be an issue, but strictly speaking, -u doesn't guarantee the name is unique. On the other hand we don't need a loop (or further directories) with this, so the simplicity of it might be preferable over correctness... -- Stefano
On Wed, Apr 05, 2023 at 02:23:24PM +0200, Stefano Brivio wrote:On Wed, 5 Apr 2023 11:56:42 +1000 David Gibson <david(a)gibson.dropbear.id.au> wrote:Yeah, I know.context_run() has a race condition if two commands are run in close proximity (generally involving at least one in the background). Because we always use the same name for the temporary fifo files, if another command is issued while the fifos for the first still exist, mkfifo will fail, typically causing the entire test script to jam. Create unique names for the temporary fifos to avoid this problem. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- test/lib/context | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/test/lib/context b/test/lib/context index d9d8260..09cad89 100644 --- a/test/lib/context +++ b/test/lib/context @@ -93,8 +93,8 @@ context_run() { __name="$1" __log="${LOGDIR}/context_${__name}.log" __enter="${STATESETUP}/context_${__name}.enter" - __stdout="${STATESETUP}/context_${__name}.stdout" - __stderr="${STATESETUP}/context_${__name}.stderr" + __stdout="$(mktemp -u "${STATESETUP}/context_${__name}.stdout.XXXXXXXX")" + __stderr="$(mktemp -u "${STATESETUP}/context_${__name}.stderr.XXXXXXXX")"In practice, this is never going to be an issue, but strictly speaking, -u doesn't guarantee the name is unique.On the other hand we don't need a loop (or further directories) with this, so the simplicity of it might be preferable over correctness...Right, that's the conclusion I came to as well. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
On Wed, 5 Apr 2023 11:56:42 +1000 David Gibson <david(a)gibson.dropbear.id.au> wrote:context_run() has a race condition if two commands are run in close proximity (generally involving at least one in the background). Because we always use the same name for the temporary fifo files, if another command is issued while the fifos for the first still exist, mkfifo will fail, typically causing the entire test script to jam. Create unique names for the temporary fifos to avoid this problem. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>Also applied. -- Stefano