[PATCH RFC] fstests: allow running custom hooks

[Qu Wenruo <wqu@suse.com>]

This patch will allow fstests to run custom hooks before and after each
test case.

These hooks will need to follow requirements:

- Both hook files needs to be executable
  Or they will just be ignored

- Stderr and stdout will be redirected to "$seqres.full"
  With extra separator to distinguish the hook output with real
  test output

  Thus if any of the hook is specified, all tests will generate
  "$seqres.full" which may increase the disk usage for results.

- Error in hooks script will be ignored completely

- Environment variable "$HOOK_TEMP" will be exported for both hooks
  And the variable will be ensured not to change for both hooks.

  Thus it's possible to store temporary values between the two hooks,
  like pid.

- Start hook has only one parameter passed in
  $1 is "$seq" from "check" script. The content will the path of current
  test case. E.g "tests/btrfs/001"

- End hook has two parameters passed in
  $1 is the same as start hook.
  $2 is the return value of the test case.
  NOTE: $2 doesn't take later golden output mismatch check nor dmesg/kmemleak
  check.

For more info, please refer to "README.hooks".

Also update .gitignore to ignore "hooks/start.hook" and "hooks/end.hook"
so that one won't accidentally submit the debug hook.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
Instead of previous attempt to manually utilize sysfs interface of
ftrace, this time just add some hooks to allow one to do whatever they
want.

RFC for how everything should be passed to hooks.
Currently it's using a mixed method, $seq/$sts is passed as paramaters,
while HOOK_TMP is passed as environmental variable.

Not sure what's the recommended way for hooks.
---
 .gitignore      |  4 +++
 README.hooks    | 72 +++++++++++++++++++++++++++++++++++++++++++++++++
 check           |  5 ++++
 common/preamble |  4 ---
 common/rc       | 43 +++++++++++++++++++++++++++++
 5 files changed, 124 insertions(+), 4 deletions(-)
 create mode 100644 README.hooks

diff --git a/.gitignore b/.gitignore
index 2d72b064..99905ff9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -201,3 +201,7 @@ tags
 # cscope files
 cscope.*
 ncscope.*
+
+# hook scripts
+/hooks/start.hook
+/hooks/end.hook
diff --git a/README.hooks b/README.hooks
new file mode 100644
index 00000000..be92a7d7
--- /dev/null
+++ b/README.hooks
@@ -0,0 +1,72 @@
+To run extra commands before and after each test case, there is the
+'hooks/start.hook' and 'hooks/end.hook' files for such usage.
+
+Some notes for those two hooks:
+
+- Both hook files needs to be executable
+  Or they will just be ignored
+
+- Stderr and stdout will be redirected to "$seqres.full"
+  With extra separator to distinguish the hook output with real
+  test output
+
+  Thus if any of the hook is specified, all tests will generate
+  "$seqres.full" which may increase the disk usage for results.
+
+- Error in hooks script will be ignored completely
+
+- Environment variable "$HOOK_TEMP" will be exported for both hooks
+  And the variable will be ensured not to change for both hooks.
+
+  Thus it's possible to store temporary values between the two hooks,
+  like pid.
+
+- Start hook has only one parameter passed in
+  $1 is "$seq" from "check" script. The content will the path of current
+  test case. E.g "tests/btrfs/001"
+
+- End hook has two parameters passed in
+  $1 is the same as start hook.
+  $2 is the return value of the test case.
+  NOTE: $2 doesn't take later golden output mismatch check nor dmesg/kmemleak
+  check.
+
+The very basic test hooks would look like:
+
+hooks/start.hook:
+  #!/bin/bash
+  seq=$1
+  echo "HOOK_TMP=$HOOK_TMP"
+  echo "seq=$seq"
+
+hooks/end.hook:
+  #!/bin/bash
+  seq=$1
+  sts=$2
+  echo "HOOK_TMP=$HOOK_TMP"
+  echo "seq=$seq"
+  echo "sts=$sts"
+
+Then run test btrfs/001 and btrfs/002, their "$seqres.full" would look like:
+
+result/btrfs/001.full:
+  === Running start hook ===
+  HOOK_TMP=/tmp/78973.hook
+  seq=tests/btrfs/001
+  === Start hook finished ===
+  === Running end hook ===
+  HOOK_TMP=/tmp/78973.hook
+  seq=tests/btrfs/001
+  sts=0
+  === End hook finished ===
+
+result/btrfs/002.full:
+  === Running start hook ===
+  HOOK_TMP=/tmp/78973.hook
+  seq=tests/btrfs/002
+  === Start hook finished ===
+  === Running end hook ===
+  HOOK_TMP=/tmp/78973.hook
+  seq=tests/btrfs/002
+  sts=0
+  === End hook finished ===
diff --git a/check b/check
index bb7e030c..f24906f5 100755
--- a/check
+++ b/check
@@ -846,6 +846,10 @@ function run_section()
 		# to be reported for each test
 		(echo 1 > $DEBUGFS_MNT/clear_warn_once) > /dev/null 2>&1
 
+		# Remove previous $seqres.full before start hook
+		rm -f $seqres.full
+
+		_run_start_hook
 		if [ "$DUMP_OUTPUT" = true ]; then
 			_run_seq 2>&1 | tee $tmp.out
 			# Because $? would get tee's return code
@@ -854,6 +858,7 @@ function run_section()
 			_run_seq >$tmp.out 2>&1
 			sts=$?
 		fi
+		_run_end_hook
 
 		if [ -f core ]; then
 			_dump_err_cont "[dumped core]"
diff --git a/common/preamble b/common/preamble
index 66b0ed05..41a12060 100644
--- a/common/preamble
+++ b/common/preamble
@@ -56,8 +56,4 @@ _begin_fstest()
 	_register_cleanup _cleanup
 
 	. ./common/rc
-
-	# remove previous $seqres.full before test
-	rm -f $seqres.full
-
 }
diff --git a/common/rc b/common/rc
index d4b1f21f..ec434aa5 100644
--- a/common/rc
+++ b/common/rc
@@ -4612,6 +4612,49 @@ _require_names_are_bytes() {
         esac
 }
 
+_run_start_hook()
+{
+	if [[ ! -d "hooks" ]]; then
+		return
+	fi
+
+	if [[ ! -x "hooks/start.hook" ]]; then
+		return
+	fi
+
+	# Export $HOOK_TMP for hooks, here we add ".hook" suffix to "$tmp",
+	# so we won't overwrite any existing $tmp.* files
+	export HOOK_TMP=$tmp.hook
+
+	echo "=== Running start hook ===" >> $seqres.full
+	# $1 is alwasy $seq
+	./hooks/start.hook $seq >> $seqres.full 2>&1
+	echo "=== Start hook finished ===" >> $seqres.full
+	unset HOOK_TMP
+}
+
+_run_end_hook()
+{
+	if [[ ! -d "hooks" ]]; then
+		return
+	fi
+
+	if [[ ! -x "hooks/end.hook" ]]; then
+		return
+	fi
+
+	# Export $HOOK_TMP for hooks, here we add ".hook" suffix to "$tmp",
+	# so we won't overwrite any existing $tmp.* files
+	export HOOK_TMP=$tmp.hook
+
+	echo "=== Running end hook ===" >> "$seqres.full"
+	# $1 is alwasy $seq
+	# $2 is alwasy $sts
+	./hooks/end.hook $seq $sts >> "$seqres.full" 2>&1
+	echo "=== End hook finished ===" >> "$seqres.full"
+	unset HOOK_TMP
+}
+
 init_rc
 
 ################################################################################
-- 
2.31.1