Check for existence of GNU-style basename()

If it doesn't exist, add an implementation to libgnu.a and config.h.

Change-Id: Ice0356030dd666d61f8a582ad09a74c843b19add
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

3 files changed, 65 insertions, 1 deletions

diff --git a/libgnu/ChangeLog b/libgnu/ChangeLog
new file mode 100644
index 00000000..3394de6d
--- /dev/null
+++ b/libgnu/ChangeLog
@@ -0,0 +1,6 @@
+2017-05-04  Ulf Hermann  <ulf.hermann@qt.io>
+
+	* Makefile.am: If GNU basename is unavailable add our own
+	implementation.
+	* basename-gnu.c: New file.
+
diff --git a/libgnu/Makefile.am b/libgnu/Makefile.am
index 1c8e6b8f..32c9aa71 100644
--- a/libgnu/Makefile.am
+++ b/libgnu/Makefile.am
@@ -36,7 +36,7 @@ MOSTLYCLEANFILES =
 MOSTLYCLEANDIRS =
 BUILT_SOURCES =
 EXTRA_DIST = endian.in.h byteswap.in.h sys_mman.win32.h mman_win32.c sysconf_win32.c ar.in.h features.in.h \
-             stdio_ext.in.h fts.in.h
+             stdio_ext.in.h fts.in.h basename-gnu.c
 CLEANFILES =
 SUFFIXES =
 
@@ -104,3 +104,7 @@ if USE_WIN32_SYSCONF
 libgnu_a_SOURCES += sysconf_win32.c
 endif
 endif
+
+if !HAVE_BASENAME
+libgnu_a_SOURCES += basename-gnu.c
+endif
diff --git a/libgnu/basename-gnu.c b/libgnu/basename-gnu.c
new file mode 100644
index 00000000..7feee81a
--- /dev/null
+++ b/libgnu/basename-gnu.c
@@ -0,0 +1,54 @@
+/* Implementation of GNU-style basename()
+   Copyright (C) 2017 The Qt Company Ltd.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "dosname.h"
+#include <string.h>
+
+/* On windows, file names with ':' in them are invalid, so we don't have to
+   add a special case for them. If we get an invalid path as input, we may
+   return a nonsensical path as output. This assumption allows us to use the
+   simple strrpos() equivalent below, without any allocation. */
+
+char *
+basename (const char *name)
+{
+  size_t prefix = FILE_SYSTEM_PREFIX_LEN(name);
+  size_t length = strlen(name);
+
+  while (length > prefix) {
+    --length;
+    if (ISSLASH(name[length]))
+      return (char *)name + length + 1;
+  }
+
+  return (char *)name + prefix;
+}