Path::strip_last_element removes path delimiter

Remove the trailing slash of a path where the path is not "/".
New Path::append_element convenience function.

Fixes #1744

repos/libports/src/lib/libc/file_operations.cc

@@ -128,8 +128,7 @@ static void resolve_symlinks(char const *path, Absolute_path &resolved_path)
 			PDBGV("path_element = %s", path_element);
 
 			try {
-				next_iteration_working_path.append("/");
+				next_iteration_working_path.append_element(path_element);
-				next_iteration_working_path.append(path_element);
 			} catch (Genode::Path_base::Path_too_long) {
 				errno = ENAMETOOLONG;
 				throw Symlink_resolve_error();
@@ -167,7 +166,7 @@ static void resolve_symlinks(char const *path, Absolute_path &resolved_path)
 						/* relative target */
 						next_iteration_working_path.strip_last_element();
 						try {
-							next_iteration_working_path.append(symlink_target);
+							next_iteration_working_path.append_element(symlink_target);
 						} catch (Genode::Path_base::Path_too_long) {
 							errno = ENAMETOOLONG;
 							throw Symlink_resolve_error();
@@ -203,7 +202,7 @@ static void resolve_symlinks_except_last_element(char const *path, Absolute_path
 	Absolute_path absolute_path_last_element(path, cwd().base());
 	absolute_path_last_element.keep_only_last_element();
 	try {
-		resolved_path.append(absolute_path_last_element.base());
+		resolved_path.append_element(absolute_path_last_element.base());
 	} catch (Genode::Path_base::Path_too_long) {
 		errno = ENAMETOOLONG;
 		throw Symlink_resolve_error();
@@ -364,8 +363,7 @@ extern "C" int fstatat(int libc_fd, char const *path, struct stat *buf, int flag
 
 	if (libc_fd == AT_FDCWD) {
 		abs_path = cwd();
-		abs_path.append("/");
+		abs_path.append_element(path);
-		abs_path.append(path);
 	} else {
 		Libc::File_descriptor *fd =
 			Libc::file_descriptor_allocator()->find_by_libc_fd(libc_fd);

repos/os/include/file_system/util.h

@@ -4,6 +4,13 @@
  * \date   2012-04-11
  */
 
+/*
+ * Copyright (C) 2012-2016 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
 #ifndef _FILE_SYSTEM__UTIL_H_
 #define _FILE_SYSTEM__UTIL_H_
 
@@ -89,7 +96,6 @@ namespace File_system {
 			} catch (Lookup_failed) {
 				Genode::Path<MAX_PATH_LEN> target(path);
 				target.strip_last_element();
-				target.remove_trailing('/');
 				fs.close(ensure_dir(fs, target.base()));
 			}
 		}

repos/os/include/os/path.h

@@ -5,7 +5,7 @@
  */
 
 /*
- * Copyright (C) 2011-2013 Genode Labs GmbH
+ * Copyright (C) 2011-2016 Genode Labs GmbH
  *
  * This file is part of the Genode OS framework, which is distributed
  * under the terms of the GNU General Public License version 2.
@@ -267,7 +267,8 @@ class Genode::Path_base
 
 		void strip_last_element()
 		{
-			last_element(_path)[1] = 0;
+			char *p = last_element(_path);
+			p[p == _path ? 1 : 0] = 0;
 		}
 
 		bool equals(Path_base const &ref) const { return strcmp(ref._path, _path) == 0; }
@@ -310,6 +311,12 @@ class Genode::Path_base
 
 		void append(char const *str) { _append(str); _canonicalize(); }
 
+		void append_element(char const *str)
+		{
+			_append("/"); _append(str);
+			_canonicalize();
+		}
+
 		bool operator == (char const *other) const
 		{
 			return strcmp(_path, other) == 0;

repos/os/include/vfs/fs_file_system.h

@@ -173,7 +173,6 @@ class Vfs::Fs_file_system : public File_system
 
 			Absolute_path dir_path(path);
 			dir_path.strip_last_element();
-			dir_path.remove_trailing('/');
 
 			Absolute_path file_name(path);
 			file_name.keep_only_last_element();
@@ -340,7 +339,6 @@ class Vfs::Fs_file_system : public File_system
 		{
 			Absolute_path dir_path(path);
 			dir_path.strip_last_element();
-			dir_path.remove_trailing('/');
 
 			Absolute_path file_name(path);
 			file_name.keep_only_last_element();
@@ -368,7 +366,6 @@ class Vfs::Fs_file_system : public File_system
 			 */
 			Absolute_path abs_path(path);
 			abs_path.strip_last_element();
-			abs_path.remove_trailing('/');
 
 			Absolute_path symlink_name(path);
 			symlink_name.keep_only_last_element();
@@ -397,14 +394,12 @@ class Vfs::Fs_file_system : public File_system
 
 			Absolute_path from_dir_path(from_path);
 			from_dir_path.strip_last_element();
-			from_dir_path.remove_trailing('/');
 
 			Absolute_path from_file_name(from_path);
 			from_file_name.keep_only_last_element();
 
 			Absolute_path to_dir_path(to_path);
 			to_dir_path.strip_last_element();
-			to_dir_path.remove_trailing('/');
 
 			Absolute_path to_file_name(to_path);
 			to_file_name.keep_only_last_element();
@@ -457,7 +452,6 @@ class Vfs::Fs_file_system : public File_system
 			 */
 			Absolute_path abs_path(to);
 			abs_path.strip_last_element();
-			abs_path.remove_trailing('/');
 
 			Absolute_path symlink_name(to);
 			symlink_name.keep_only_last_element();
@@ -528,7 +522,6 @@ class Vfs::Fs_file_system : public File_system
 
 			Absolute_path dir_path(path);
 			dir_path.strip_last_element();
-			dir_path.remove_trailing('/');
 
 			Absolute_path file_name(path);
 			file_name.keep_only_last_element();