From f0679266bda765f4e1e15bfee97d2817d3bd78ea Mon Sep 17 00:00:00 2001
From: BharatDBPG <bharatdbpg@gmail.com>
Date: Wed, 19 Nov 2025 17:43:53 +0530
Subject: [PATCH] libpq: Add exit() function check for Meson build and
 whitelist pthread_exit()
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The Makefile-based build already performs a safety check to ensure that
libpq does not accidentally reference exit() or related termination
functions.

Meson, however, did not run this check. As a result, Meson builds could
miss accidental references to exit()-family functions which ideally
should never be called inside libpq.

This patch adds the missing scan to the Meson build by:
  • Scanning the libpq .o files using nm and filtering through the same
    whitelist logic as the Makefile.
  • Adding pthread_exit() to the Meson whitelist, matching the behavior
    of the existing Makefile check.

With this change, both Makefile and Meson builds apply the same
validation for unwanted exit() usage.
---
 meson.build                      |  1 +
 src/interfaces/libpq/Makefile    |  5 +++--
 src/interfaces/libpq/meson.build | 30 ++++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/meson.build b/meson.build
index c1e17aa3040..47588ead9fb 100644
--- a/meson.build
+++ b/meson.build
@@ -3820,6 +3820,7 @@ alias_target('bin', bin_targets + [libpq_st])
 alias_target('pl', pl_targets)
 alias_target('contrib', contrib_targets)
 alias_target('testprep', testprep_targets)
+alias_target('run-check-libpq', [check_exit_target])
 
 alias_target('world', all_built, docs)
 alias_target('install-world', install_quiet, installdocs)
diff --git a/src/interfaces/libpq/Makefile b/src/interfaces/libpq/Makefile
index da6650066d4..7b20d84d51d 100644
--- a/src/interfaces/libpq/Makefile
+++ b/src/interfaces/libpq/Makefile
@@ -137,14 +137,15 @@ $(stlib): $(OBJS_STATIC)
 # which seems to insert references to that even in pure C code. Excluding
 # __tsan_func_exit is necessary when using ThreadSanitizer data race detector
 # which use this function for instrumentation of function exit.
-# Skip the test when profiling, as gcc may insert exit() calls for that.
+#Excluding pthread_exit allows legitimate thread shutdown paths used on some builds.
+#Skip the test when profiling, as gcc may insert exit() calls for that.
 # Also skip the test on platforms where libpq infrastructure may be provided
 # by statically-linked libraries, as we can't expect them to honor this
 # coding rule.
 libpq-refs-stamp: $(shlib)
 ifneq ($(enable_coverage), yes)
 ifeq (,$(filter solaris,$(PORTNAME)))
-	@if nm -A -u $< 2>/dev/null | grep -v -e __cxa_atexit -e __tsan_func_exit | grep exit; then \
+	@if nm -A -u $< 2>/dev/null | grep -v -e __cxa_atexit -e __tsan_func_exit -e pthread_exit | grep exit; then \
 		echo 'libpq must not be calling any function which invokes exit'; exit 1; \
 	fi
 endif
diff --git a/src/interfaces/libpq/meson.build b/src/interfaces/libpq/meson.build
index a74e885b169..30324731e9c 100644
--- a/src/interfaces/libpq/meson.build
+++ b/src/interfaces/libpq/meson.build
@@ -85,6 +85,36 @@ libpq = declare_dependency(
   include_directories: [include_directories('.')]
 )
 
+# Sanity check to ensure libpq does not contain any unintended references
+# to exit() in its object files.  Client libraries must not terminate the
+# calling process, so we scan all libpq .o files with 'nm' and fail the
+# build if a direct exit() reference is found.  Certain harmless symbols
+# (__cxa_atexit, __tsan_func_exit, pthread_exit) are whitelisted.
+# Skip on cross-builds, sanitizer coverage, and Windows
+
+if not meson.is_cross_build() and not get_option('b_coverage') and host_system != 'windows'
+  check_exit_target = custom_target(
+    'check-libpq-no-exit',
+    output: 'libpq-nm-stamp',
+    depends: [libpq_st, libpq_so],
+    build_by_default: true,
+    command: [
+      'bash','-eu', '-c',
+      '''
+      echo "Checking that libpq object files do not reference exit()..."
+      obj_files=$(find src/interfaces/libpq -type f -name "*.o")
+      for f in $obj_files; do
+        if nm -u "$f" 2>/dev/null| grep -v -E '__cxa_atexit|__tsan_func_exit|pthread_exit'| grep exit; then
+          echo "ERROR: exit()-related reference found in: $f"
+          exit 1
+        fi
+      done
+      touch  @OUTPUT@
+      '''.format(meson.current_build_dir())
+    ],
+  )
+
+endif
 private_deps = [
   frontend_stlib_code,
   libpq_deps,
-- 
2.43.0