pkg-config-wrapper: fix a race condition

Currently, pkg-config-wrapper assumes, that if a pkg-config call fails
once, then it will fail again. So if pkg-config fails during the whitelist
check, it just continues and lets the next call to pkg-config produce the
error.

However, this is racy when packages are built in parallel: It can happen,
that the pkg-config whitelist call fails, because the package is not yet
available, and the following 'real' pkg-config call succeeds because the
.pc was installed in between the two calls.
As a result the whitelist check is bypassed. This usually leads to build
errors because followup pkg-config calls to query cflags or libs will be
blocked.

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>

1 files changed, 9 insertions, 2 deletions

diff --git a/scripts/pkg-config-wrapper b/scripts/pkg-config-wrapper
index 79018c63c..53be1a987 100755
--- a/scripts/pkg-config-wrapper
+++ b/scripts/pkg-config-wrapper
@@ -78,8 +78,15 @@ check_pipe_status() {
 	done
 }
 
-if [ -n "${PKGCONFIG_WHITELIST_SRC}" ]; then
-    pkgs="$(pkg-config.real --print-provides "${@}" 2>/dev/null | awk '{print $1}' && check_pipe_status)" &&
+if [ -n "${PKGCONFIG_WHITELIST_SRC}" -a "${1}" != "--version" -a "${1}" != "--help" ]; then
+    error="$(mktemp "${PTXDIST_TEMPDIR}/pkg-config.XXXXXX")"
+    pkgs="$(pkg-config.real --print-provides "${@}" 2> "${error}" | awk '{print $1}' && check_pipe_status)"
+    if [ $? -ne 0 ]; then
+	cat "${error}" >&2
+	rm "${error}"
+	exit 1
+    fi
+    rm "${error}"
     for pkg in ${pkgs}; do
 	if [[ ! " ${whitelist} " =~ " ${pkg} " && ! "${pkg}" =~ '-uninstalled' ]]; then
 	    echo "$(basename ${0}): warning: blocking '${pkg}': not selected by '${PKGCONFIG_WHITELIST_SRC}'" >&2