From eef46c372f64f40dd75415b2c504c73138719c8d Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 11 Feb 2015 18:50:38 +0100
Subject: [PATCH] tree-wide: whenever we include libgen.h, immediately undefine
 basename()

Also, document in adjacent comments and in CODING_STYLE why we do that.
---
 CODING_STYLE                       | 6 ++++++
 src/libsystemd/sd-bus/bus-kernel.c | 7 ++++++-
 src/machine/machinectl.c           | 5 +++++
 src/shared/util.c                  | 6 +++++-
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/CODING_STYLE b/CODING_STYLE
index 1d1d97049..557401348 100644
--- a/CODING_STYLE
+++ b/CODING_STYLE
@@ -202,3 +202,9 @@
   b) socket() and socketpair() must get SOCK_CLOEXEC passed
   c) recvmsg() must get MSG_CMSG_CLOEXEC set
   d) F_DUPFD_CLOEXEC should be used instead of F_DUPFD, and so on
+
+- We never use the XDG version of basename(). glibc defines it in
+  libgen.h. The only reason to include that file is because dirname()
+  is needed. Everytime you need that please immediately undefine
+  basename(), and add a comment about it, so that no code ever ends up
+  using the XDG version!
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index 1714188ff..b884074d9 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -25,10 +25,15 @@
 
 #include <fcntl.h>
 #include <malloc.h>
-#include <libgen.h>
 #include <sys/mman.h>
 #include <sys/prctl.h>
 
+/* When we include libgen.h because we need dirname() we immediately
+ * undefine basename() since libgen.h defines it as a macro to the XDG
+ * version which is really broken. */
+#include <libgen.h>
+#undef basename
+
 #include "util.h"
 #include "strv.h"
 #include "memfd-util.h"
diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
index 16ce2f424..9f8c68b18 100644
--- a/src/machine/machinectl.c
+++ b/src/machine/machinectl.c
@@ -31,8 +31,13 @@
 #include <arpa/inet.h>
 #include <net/if.h>
 #include <sys/mount.h>
+
+/* When we include libgen.h because we need dirname() we immediately
+ * undefine basename() since libgen.h defines it as a macro to the XDG
+ * version which is really broken. */
 #include <libgen.h>
 #undef basename
+
 #include "sd-bus.h"
 #include "log.h"
 #include "util.h"
diff --git a/src/shared/util.c b/src/shared/util.c
index c53f9cdb6..f5fcebebe 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -60,10 +60,14 @@
 #include <locale.h>
 #include <sys/personality.h>
 #include <sys/xattr.h>
-#include <libgen.h>
 #include <sys/statvfs.h>
 #include <sys/file.h>
 #include <linux/fs.h>
+
+/* When we include libgen.h because we need dirname() we immediately
+ * undefine basename() since libgen.h defines it as a macro to the XDG
+ * version which is really broken. */
+#include <libgen.h>
 #undef basename
 
 #ifdef HAVE_SYS_AUXV_H
-- 
2.30.2