libmpathutil: really always use glibc basename()

Despite 03a5456 ("libmultipath: always use glibc basename()"), we
still call the system library's basename() from libmultipath.
musl libc until 1.24 provided a prototype for basename() in string.h,
which was not correct and was resolved to the destructive POSIX
basename(). musl libc 1.25 removed this prototype.

While the remaining code path doesn't strictly depend on the non-destructive
behavior of glibc's basename(), it's cleaner and safer to use the same
implementation everywhere.

Fixes: 03a5456 ("libmultipath: always use glibc basename()")
Fixes: #84

Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Khem Raj <raj.khem@gmail.com>
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>

libmpathutil/libmpathutil.version

@@ -129,3 +129,7 @@ LIBMPATHUTIL_2.0 {
 	vector_move_up;
 	vector_sort;
 };
+
+LIBMPATHUTIL_2.1 {
+	libmp_basename;
+};

libmpathutil/util.c

@@ -32,18 +32,15 @@ strchop(char *str)
 	return i;
 }
 
-#ifndef __GLIBC__
 /*
  * glibc's non-destructive version of basename()
  * License: LGPL-2.1-or-later
  */
-static const char *__basename(const char *filename)
+const char *libmp_basename(const char *filename)
 {
 	char *p = strrchr(filename, '/');
 	return p ? p + 1 : filename;
 }
-#define basename(x) __basename(x)
-#endif
 
 int
 basenamecpy (const char *src, char *dst, size_t size)

libmpathutil/util.h

@@ -12,6 +12,11 @@
 #include <stdio.h>
 
 size_t strchop(char *);
+
+const char *libmp_basename(const char *filename);
+#ifndef __GLIBC__
+#define basename(x) libmp_basename(x)
+#endif
 int basenamecpy (const char *src, char *dst, size_t size);
 int filepresent (const char *run);
 char *get_next_string(char **temp, const char *split_char);

tests/util.c

@@ -16,13 +16,15 @@
  *
  */
 
+#define _GNU_SOURCE
 #include <stdbool.h>
 #include <stdarg.h>
 #include <stddef.h>
 #include <setjmp.h>
 #include <stdlib.h>
 #include <cmocka.h>
 #include <endian.h>
+#include <string.h>
 #include "util.h"
 
 #include "globals.c"
@@ -163,6 +165,34 @@ static int test_basenamecpy(void)
 	return cmocka_run_group_tests(tests, NULL, NULL);
 }
 
+static void test_basename_01(void **state)
+{
+	const char *path = "/foo/bar";
+	const char *base;
+
+	base = basename(path);
+	assert_string_equal(base, "bar");
+	assert_string_equal(path, "/foo/bar");
+}
+
+static void test_basename_02(void **state)
+{
+	const char *path = "/foo/bar/";
+	const char *base;
+
+	base = basename(path);
+	assert_string_equal(base, "");
+	assert_string_equal(path, "/foo/bar/");
+}
+
+static int test_basename(void) {
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(test_basename_01),
+		cmocka_unit_test(test_basename_02),
+	};
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}
+
 /*
  * On big endian systems, if bitfield_t is 32bit, we need
  * to swap the two 32 bit parts of a 64bit value to make
@@ -946,6 +976,7 @@ int main(void)
 
 	init_test_verbosity(-1);
 	ret += test_basenamecpy();
+	ret += test_basename();
 	ret += test_bitmasks();
 	ret += test_strlcpy();
 	ret += test_strlcat();