[PATCH v7 14/14] selftests/ftrace: Walk up parent dirs to find test.d/functions

[wen.yang@linux.dev]

From: Wen Yang <wen.yang@linux.dev>

When a subdirectory is passed (e.g. an RV monitor's test directory),
ftracetest fell back to its own functions file, losing the RV-specific
check_requires handling for ':monitor' and ':reactor' requirements.

Walk up from OPT_TEST_DIR until a directory containing test.d/functions
is found, stopping after five levels so a stray argument cannot reach an
unrelated functions file further up the tree.  When no such directory is
found the previous default is kept.

Note that TOP_DIR also feeds LOG_TOP_DIR, so logs now follow the
directory the tests were found in: an RV run writes to
verification/logs rather than ftrace/logs.

Signed-off-by: Wen Yang <wen.yang@linux.dev>
---
 tools/testing/selftests/ftrace/ftracetest | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/ftrace/ftracetest b/tools/testing/selftests/ftrace/ftracetest
index 0a56bf209f6c..3d3c3a4dfa34 100755
--- a/tools/testing/selftests/ftrace/ftracetest
+++ b/tools/testing/selftests/ftrace/ftracetest
@@ -159,9 +159,22 @@ parse_opts() { # opts
   if [ -n "$OPT_TEST_CASES" ]; then
     TEST_CASES=$OPT_TEST_CASES
   fi
-  if [ -n "$OPT_TEST_DIR" -a -f "$OPT_TEST_DIR"/test.d/functions ]; then
-    TOP_DIR=$OPT_TEST_DIR
-    TEST_DIR=$TOP_DIR/test.d
+  if [ -n "$OPT_TEST_DIR" ]; then
+    # A subdirectory of test.d can be given; walk up to the directory
+    # holding test.d/functions.  The bound keeps a stray directory from
+    # reaching an unrelated functions file further up the tree.
+    local dir=$OPT_TEST_DIR
+    local depth=0
+    while [ "$depth" -lt 5 ]; do
+      if [ -f "$dir/test.d/functions" ]; then
+        TOP_DIR=$dir
+        TEST_DIR=$TOP_DIR/test.d
+        break
+      fi
+      case "$dir" in /|//|.) break;; esac
+      dir=$(dirname "$dir")
+      depth=$((depth + 1))
+    done
   fi
 }
 
-- 
2.25.1