+
+static
+void append_path_parts(const char *path, GPtrArray *parts)
+{
+ const char *ch = path;
+ const char *last = path;
+
+ while (true) {
+ if (*ch == G_DIR_SEPARATOR || *ch == '\0') {
+ if (ch - last > 0) {
+ GString *part = g_string_new(NULL);
+
+ assert(part);
+ g_string_append_len(part, last, ch - last);
+ g_ptr_array_add(parts, part);
+ }
+
+ if (*ch == '\0') {
+ break;
+ }
+
+ last = ch + 1;
+ }
+
+ ch++;
+ }
+}
+
+static
+void destroy_gstring(void *gstring)
+{
+ (void) g_string_free(gstring, TRUE);
+}
+
+BT_HIDDEN
+GString *bt_common_normalize_path(const char *path, const char *wd)
+{
+ size_t i;
+ GString *norm_path;
+ GPtrArray *parts = NULL;
+
+ assert(path);
+ norm_path = g_string_new(G_DIR_SEPARATOR_S);
+ if (!norm_path) {
+ goto error;
+ }
+
+ parts = g_ptr_array_new_with_free_func(destroy_gstring);
+ if (!parts) {
+ goto error;
+ }
+
+ if (path[0] != G_DIR_SEPARATOR) {
+ /* Relative path: start with working directory */
+ if (wd) {
+ append_path_parts(wd, parts);
+ } else {
+ gchar *cd = g_get_current_dir();
+
+ append_path_parts(cd, parts);
+ g_free(cd);
+ }
+ }
+
+ /* Append parts of the path parameter */
+ append_path_parts(path, parts);
+
+ /* Resolve special `..` and `.` parts */
+ for (i = 0; i < parts->len; i++) {
+ GString *part = g_ptr_array_index(parts, i);
+
+ if (strcmp(part->str, "..") == 0) {
+ if (i == 0) {
+ /*
+ * First part of absolute path is `..`:
+ * this is invalid.
+ */
+ goto error;
+ }
+
+ /* Remove `..` and previous part */
+ g_ptr_array_remove_index(parts, i - 1);
+ g_ptr_array_remove_index(parts, i - 1);
+ i -= 2;
+ } else if (strcmp(part->str, ".") == 0) {
+ /* Remove `.` */
+ g_ptr_array_remove_index(parts, i);
+ i -= 1;
+ }
+ }
+
+ /* Create normalized path with what's left */
+ for (i = 0; i < parts->len; i++) {
+ GString *part = g_ptr_array_index(parts, i);
+
+ g_string_append(norm_path, part->str);
+
+ if (i < parts->len - 1) {
+ g_string_append_c(norm_path, G_DIR_SEPARATOR);
+ }
+ }
+
+ goto end;
+
+error:
+ if (norm_path) {
+ g_string_free(norm_path, TRUE);
+ norm_path = NULL;
+ }
+
+end:
+ if (parts) {
+ g_ptr_array_free(parts, TRUE);
+ }
+
+ return norm_path;
+}
+
+BT_HIDDEN
+size_t bt_common_get_page_size(void)
+{
+ int page_size;
+
+ page_size = bt_sysconf(_SC_PAGESIZE);
+ if (page_size < 0) {
+ printf_error("Cannot get system page size.");
+ abort();
+ }
+
+ return page_size;
+}