From 9971fba5848ca3928b54e123a338d454e6c65283 Mon Sep 17 00:00:00 2001
From: Tristan Partin <tristan@neon.tech>
Date: Mon, 12 May 2025 12:36:07 -0500
Subject: [PATCH] Properly configure the dynamic loader to load our compiled
 libraries (#11858)

The first line in /etc/ld.so.conf is:

	/etc/ld.so.conf.d/*

We want to control library load order so that our compiled binaries are
picked up before others from system packages. The previous solution
allowed the system libraries to load before ours.

Part-of: https://github.com/neondatabase/neon/issues/11857

Signed-off-by: Tristan Partin <tristan@neon.tech>
---
 compute/compute-node.Dockerfile                 | 3 ++-
 compute/etc/ld.so.conf.d/00-neon.conf           | 1 +
 docker-compose/compute_wrapper/shell/compute.sh | 8 ++++++++
 3 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 compute/etc/ld.so.conf.d/00-neon.conf

diff --git a/compute/compute-node.Dockerfile b/compute/compute-node.Dockerfile
index 6233eaf709..e6e6053554 100644
--- a/compute/compute-node.Dockerfile
+++ b/compute/compute-node.Dockerfile
@@ -1971,7 +1971,8 @@ COPY --from=sql_exporter_preprocessor --chmod=0644 /home/nonroot/compute/etc/sql
 COPY --from=sql_exporter_preprocessor --chmod=0644 /home/nonroot/compute/etc/neon_collector_autoscaling.yml /etc/neon_collector_autoscaling.yml
 
 # Make the libraries we built available
-RUN echo '/usr/local/lib' >> /etc/ld.so.conf && /sbin/ldconfig
+COPY --chmod=0666 compute/etc/ld.so.conf.d/00-neon.conf /etc/ld.so.conf.d/00-neon.conf
+RUN /sbin/ldconfig
 
 # rsyslog config permissions
 # directory for rsyslogd pid file
diff --git a/compute/etc/ld.so.conf.d/00-neon.conf b/compute/etc/ld.so.conf.d/00-neon.conf
new file mode 100644
index 0000000000..e8e4bdcd42
--- /dev/null
+++ b/compute/etc/ld.so.conf.d/00-neon.conf
@@ -0,0 +1 @@
+/usr/local/lib
diff --git a/docker-compose/compute_wrapper/shell/compute.sh b/docker-compose/compute_wrapper/shell/compute.sh
index 723b2f8afb..20a1ffb7a0 100755
--- a/docker-compose/compute_wrapper/shell/compute.sh
+++ b/docker-compose/compute_wrapper/shell/compute.sh
@@ -14,6 +14,14 @@ PG_VERSION=${PG_VERSION:-14}
 CONFIG_FILE_ORG=/var/db/postgres/configs/config.json
 CONFIG_FILE=/tmp/config.json
 
+# Test that the first library path that the dynamic loader looks in is the path
+# that we use for custom compiled software
+first_path="$(ldconfig --verbose 2>/dev/null \
+    | grep --invert-match ^$'\t' \
+    | cut --delimiter=: --fields=1 \
+    | head --lines=1)"
+test "$first_path" == '/usr/local/lib' || true # Remove the || true in a follow-up PR. Needed for backwards compat.
+
 echo "Waiting pageserver become ready."
 while ! nc -z pageserver 6400; do
      sleep 1;