modpost: introduce get_basename() helper

The logic to retrieve the basename appears multiple times.
Factor out the common pattern into a helper function.

I copied kbasename() from include/linux/string.h and renamed it
to get_basename().

Signed-off-by: Masahiro Yamada <[e-mail]>
Reviewed-by: Nicolas Schier <[e-mail]>

scripts/mod/modpost.c

···
 	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
 }
 
+/**
+ * get_basename - return the last part of a pathname.
+ *
+ * @path: path to extract the filename from.
+ */
+const char *get_basename(const char *path)
+{
+	const char *tail = strrchr(path, '/');
+
+	return tail ? tail + 1 : path;
+}
+
 char *read_text_file(const char *filename)
 {
 	struct stat st;
···
 	const char *base;
 	int dirlen, ret;
 
-	base = strrchr(object, '/');
-	if (base) {
-		base++;
-		dirlen = base - object;
-	} else {
-		dirlen = 0;
-		base = object;
-	}
+	base = get_basename(object);
+	dirlen = base - object;
 
 	ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
 		       dirlen, object, base);
···
 		s->crc_valid = exp->crc_valid;
 		s->crc = exp->crc;
 
-		basename = strrchr(mod->name, '/');
-		if (basename)
-			basename++;
-		else
-			basename = mod->name;
+		basename = get_basename(mod->name);
 
 		if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
 			modpost_log(!allow_missing_ns_imports,
···
 {
 	const char *mod_name;
 
-	mod_name = strrchr(mod->name, '/');
-	if (mod_name == NULL)
-		mod_name = mod->name;
-	else
-		mod_name++;
+	mod_name = get_basename(mod->name);
+
 	if (strlen(mod_name) >= MODULE_NAME_LEN)
 		error("module name is too long [%s.ko]\n", mod->name);
 }
···
 			continue;
 
 		s->module->seen = true;
-		p = strrchr(s->module->name, '/');
-		if (p)
-			p++;
-		else
-			p = s->module->name;
+		p = get_basename(s->module->name);
 		buf_printf(b, "%s%s", first ? "" : ",", p);
 		first = 0;
 	}

scripts/mod/modpost.h

···
 /* from modpost.c */
 extern bool target_is_big_endian;
 extern bool host_is_big_endian;
+const char *get_basename(const char *path);
 char *read_text_file(const char *filename);
 char *get_line(char **stringp);
 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym);

scripts/mod/sumversion.c

···
 
 	cmd = xmalloc(strlen(objfile) + sizeof("..cmd"));
 
-	base = strrchr(objfile, '/');
-	if (base) {
-		base++;
-		dirlen = base - objfile;
-		sprintf(cmd, "%.*s.%s.cmd", dirlen, objfile, base);
-	} else {
-		dirlen = 0;
-		sprintf(cmd, ".%s.cmd", objfile);
-	}
+	base = get_basename(objfile);
+	dirlen = base - objfile;
+	sprintf(cmd, "%.*s.%s.cmd", dirlen, objfile, base);
+
 	dir = xmalloc(dirlen + 1);
 	strncpy(dir, objfile, dirlen);
 	dir[dirlen] = '\0';