From 6ba2d6840bc68de67216f6c07bbcfd52bdc9d0e4 Mon Sep 17 00:00:00 2001
From: "W.C.A. Wijngaards" <wouter@nlnetlabs.nl>
Date: Tue, 8 Jul 2025 09:29:27 +0200
Subject: [PATCH] - Fix to improve dnstap discovery on Fedora.

---
 configure        | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
 dnstap/dnstap.m4 | 24 ++++++++++++++++
 doc/Changelog    |  3 ++
 3 files changed, 99 insertions(+)

diff --git a/configure b/configure
index af58f5ef6..4c9be7ba7 100755
--- a/configure
+++ b/configure
@@ -685,6 +685,7 @@ opt_dnstap_socket_path
 ENABLE_DNSTAP
 PROTOBUFC_LIBS
 PROTOBUFC_CFLAGS
+PROTOC_GEN_C
 PROTOC_C
 PROTOC
 UBSYMS
@@ -24414,6 +24415,77 @@ fi
 	  as_fn_error $? "The protoc or protoc-c program was not found. It is needed for dnstap, use --disable-dnstap, or install protobuf-c to provide protoc or protoc-c" "$LINENO" 5
 	fi
 
+	# Check for protoc-gen-c plugin
+	# Extract the first word of "protoc-gen-c", so it can be a program name with args.
+set dummy protoc-gen-c; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_path_PROTOC_GEN_C+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  case $PROTOC_GEN_C in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_PROTOC_GEN_C="$PROTOC_GEN_C" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_path_PROTOC_GEN_C="$as_dir$ac_word$ac_exec_ext"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  ;;
+esac
+fi
+PROTOC_GEN_C=$ac_cv_path_PROTOC_GEN_C
+if test -n "$PROTOC_GEN_C"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $PROTOC_GEN_C" >&5
+printf "%s\n" "$PROTOC_GEN_C" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+	if test -z "$PROTOC_GEN_C"; then
+	  as_fn_error $? "The protoc-gen-c plugin was not found. It is needed for dnstap, use --disable-dnstap, or install protobuf-c-compiler to provide protoc-gen-c" "$LINENO" 5
+	fi
+
+	# Test that protoc-gen-c actually works
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if protoc-gen-c plugin works" >&5
+printf %s "checking if protoc-gen-c plugin works... " >&6; }
+	cat > conftest.proto << EOF
+syntax = "proto2";
+message TestMessage {
+  optional string test_field = 1;
+}
+EOF
+	if $PROTOC_C --c_out=. conftest.proto >/dev/null 2>&1; then
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+	  rm -f conftest.proto conftest.pb-c.c conftest.pb-c.h
+	else
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+	  rm -f conftest.proto conftest.pb-c.c conftest.pb-c.h
+	  as_fn_error $? "The protoc-gen-c plugin is not working properly. Please ensure protobuf-c-compiler is properly installed" "$LINENO" 5
+	fi
+
+
 # Check whether --with-protobuf-c was given.
 if test ${with_protobuf_c+y}
 then :
diff --git a/dnstap/dnstap.m4 b/dnstap/dnstap.m4
index 166402d81..89eda929b 100644
--- a/dnstap/dnstap.m4
+++ b/dnstap/dnstap.m4
@@ -29,6 +29,30 @@ AC_DEFUN([dt_DNSTAP],
 	if test -z "$PROTOC_C"; then
 	  AC_MSG_ERROR([[The protoc or protoc-c program was not found. It is needed for dnstap, use --disable-dnstap, or install protobuf-c to provide protoc or protoc-c]])
 	fi
+
+	# Check for protoc-gen-c plugin
+	AC_PATH_PROG([PROTOC_GEN_C], [protoc-gen-c])
+	if test -z "$PROTOC_GEN_C"; then
+	  AC_MSG_ERROR([[The protoc-gen-c plugin was not found. It is needed for dnstap, use --disable-dnstap, or install protobuf-c-compiler to provide protoc-gen-c]])
+	fi
+
+	# Test that protoc-gen-c actually works
+	AC_MSG_CHECKING([if protoc-gen-c plugin works])
+	cat > conftest.proto << EOF
+syntax = "proto2";
+message TestMessage {
+  optional string test_field = 1;
+}
+EOF
+	if $PROTOC_C --c_out=. conftest.proto >/dev/null 2>&1; then
+	  AC_MSG_RESULT([yes])
+	  rm -f conftest.proto conftest.pb-c.c conftest.pb-c.h
+	else
+	  AC_MSG_RESULT([no])
+	  rm -f conftest.proto conftest.pb-c.c conftest.pb-c.h
+	  AC_MSG_ERROR([[The protoc-gen-c plugin is not working properly. Please ensure protobuf-c-compiler is properly installed]])
+	fi
+
         AC_ARG_WITH([protobuf-c],
             AS_HELP_STRING([--with-protobuf-c=path], [Path where protobuf-c is installed, for dnstap]),
             [
diff --git a/doc/Changelog b/doc/Changelog
index 79e82e144..5729d4606 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,3 +1,6 @@
+8 July 2025: Wouter
+	- Fix to improve dnstap discovery on Fedora.
+
 3 July 2025: Wouter
 	- Fix #1300: Is 'sock-queue-timeout' a linux only feature.
 	- For #1300: implement sock-queue-timeout for FreeBSD as well.
-- 
2.47.2