+ int ret = chdir(path);
+
+ if (ret >= 0)
+ return 1;
+ return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * Save the cwd and open a given directory.
+ *
+ * \param dirname Path to the directory to open.
+ * \param dir Result pointer.
+ * \param cwd File descriptor of the current working directory.
+ *
+ * \return Standard.
+ *
+ * Opening the current directory (".") and calling fchdir() to return is
+ * usually faster and more reliable than saving cwd in some buffer and calling
+ * chdir() afterwards.
+ *
+ * If \a cwd is not \p NULL "." is opened and the resulting file descriptor is
+ * stored in \a cwd. If the function returns success, and \a cwd is not \p
+ * NULL, the caller must close this file descriptor (probably after calling
+ * fchdir(*cwd)).
+ *
+ * On errors, the function undos everything, so the caller needs neither close
+ * any files, nor change back to the original working directory.
+ *
+ * \sa getcwd(3).
+ *
+ */
+int para_opendir(const char *dirname, DIR **dir, int *cwd)
+{
+ int ret;
+
+ if (cwd) {
+ ret = para_open(".", O_RDONLY, 0);
+ if (ret < 0)
+ return ret;
+ *cwd = ret;
+ }
+ ret = para_chdir(dirname);
+ if (ret < 0)
+ goto close_cwd;
+ *dir = opendir(".");
+ if (*dir)
+ return 1;
+ ret = -ERRNO_TO_PARA_ERROR(errno);
+/* Ignore return value of fchdir() and close(). We're busted anyway. */
+ if (cwd)
+ fchdir(*cwd);
+close_cwd:
+ if (cwd)
+ close(*cwd);
+ return ret;
+}
+
+/**
+ * A wrapper for fchdir().
+ *
+ * \param fd An open file descriptor.
+ *
+ * \return Standard.
+ */
+int para_fchdir(int fd)
+{
+ if (fchdir(fd) < 0)
+ return -ERRNO_TO_PARA_ERROR(errno);
+ return 1;
+}
+
+/**
+ * A wrapper for mkdir(2).
+ *
+ * \param path Name of the directory to create.
+ * \param mode The permissions to use.
+ *
+ * \return Standard.
+ */
+int para_mkdir(const char *path, mode_t mode)
+{
+ if (!mkdir(path, mode))
+ return 1;
+ return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * Open a file and map it into memory.
+ *
+ * \param path Name of the regular file to map.
+ * \param open_mode Either \p O_RDONLY or \p O_RDWR.
+ * \param map On success, the mapping is returned here.
+ * \param size size of the mapping.
+ * \param fd_ptr The file descriptor of the mapping.
+ *
+ * If \a fd_ptr is \p NULL, the file descriptor resulting from the underlying
+ * open call is closed after mmap(). Otherwise the file is kept open and the
+ * file descriptor is returned in \a fd_ptr.
+ *
+ * \return Standard.
+ *
+ * \sa para_open(), mmap(2).
+ */
+int mmap_full_file(const char *path, int open_mode, void **map,
+ size_t *size, int *fd_ptr)
+{
+ int fd, ret, mmap_prot, mmap_flags;
+ struct stat file_status;
+
+ if (open_mode == O_RDONLY) {
+ mmap_prot = PROT_READ;
+ mmap_flags = MAP_PRIVATE;
+ } else {
+ mmap_prot = PROT_READ | PROT_WRITE;
+ mmap_flags = MAP_SHARED;
+ }
+ ret = para_open(path, open_mode, 0);
+ if (ret < 0)