Tidy the test comments and shell portability

1 file changed, 19 insertions, 5 deletions

diff --git a/tests/t0109-gitconfig.sh b/tests/t0109-gitconfig.sh
index 189ef28..7078596 100755
--- a/tests/t0109-gitconfig.sh
+++ b/tests/t0109-gitconfig.sh
@@ -1,8 +1,17 @@
 #!/bin/sh
 
+# Guards the promise that cgit reads nothing out of the home directory of
+# whichever account the web server happens to run as. Every page is fetched
+# under strace with HOME pointed at a path that is known not to exist, and
+# the run fails if any access call names that path, which is how a stray
+# read of a personal gitconfig would show up.
+
 test_description='Ensure that git does not access $HOME'
 . ./setup.sh
 
+# strace needs ptrace, which containers and hardened kernels refuse even
+# where the binary is installed, so a working run is checked as well as a
+# present binary.
 test -n "$(which strace 2>/dev/null)" || {
 	skip_all='Skipping access validation tests: strace not found'
 	test_done
@@ -16,16 +25,21 @@ strace true 2>/dev/null || {
 }
 
 test_no_home_access () {
-	non_existent_path="/path/to/some/place/that/does/not/possibly/exist"
-	while test -d "$non_existent_path"; do
-		non_existent_path="$non_existent_path/$(date +%N)"
+	# A home that happened to exist would be one git may legitimately
+	# read, leaving the check below with nothing to catch, so extend the
+	# path until nothing is there.
+	missing_home="/path/to/some/place/that/does/not/possibly/exist"
+	depth=0
+	while test -d "$missing_home"; do
+		depth=$((depth + 1))
+		missing_home="$missing_home/$depth"
 	done &&
 	strace \
-		-E HOME="$non_existent_path" \
+		-E HOME="$missing_home" \
 		-E CGIT_CONFIG="$PWD/cgitrc" \
 		-E QUERY_STRING="url=$1" \
 		-e access -f -o strace.out cgit &&
-	! grep "$non_existent_path" strace.out
+	! grep "$missing_home" strace.out
 }
 
 test_no_home_access_success() {