1 files changed, 168 insertions, 0 deletions
diff --git a/src/preprocess.c b/src/preprocess.c
new file mode 100644
index 00000000..619f67a1
--- /dev/null
+++ b/src/preprocess.c
@@ -0,0 +1,168 @@
+/*
+ * Copyright (c) 2013-2024 Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 (or any
+ * later) as published by the Free Software Foundation.
+ */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <utils.h>
+
+#include "list.h"
+#include "parser.h"
+#include "erec.h"
+
+struct str_buf {
+	uint8_t		*str;
+	uint32_t	len;
+	uint32_t	size;
+};
+
+#define STR_BUF_LEN	128
+
+static struct str_buf *str_buf_alloc(void)
+{
+	struct str_buf *buf;
+
+	buf = xzalloc(sizeof(*buf));
+	buf->str = xzalloc_array(1, STR_BUF_LEN);
+	buf->size = STR_BUF_LEN;
+
+	return buf;
+}
+
+static int str_buf_add(struct str_buf *buf, const char *str, uint32_t len)
+{
+	uint8_t *tmp;
+
+	if (len + buf->len > buf->size) {
+		buf->size = (len + buf->len) * 2;
+		tmp = xrealloc(buf->str, buf->size);
+		buf->str = tmp;
+	}
+
+	memcpy(&buf->str[buf->len], str, len);
+	buf->len += len;
+
+	return 0;
+}
+
+struct str_chunk {
+	struct list_head	list;
+	char			*str;
+	uint32_t		len;
+	bool			is_sym;
+};
+
+static void add_str_chunk(const char *x, int from, int to, struct list_head *list, bool is_sym)
+{
+	struct str_chunk *chunk;
+	int len = to - from;
+
+	chunk = xzalloc_array(1, sizeof(*chunk));
+	chunk->str = xzalloc_array(1, len + 1);
+	chunk->is_sym = is_sym;
+	chunk->len = len;
+	memcpy(chunk->str, &x[from], len);
+
+	list_add_tail(&chunk->list, list);
+}
+
+static void free_str_chunk(struct str_chunk *chunk)
+{
+	free(chunk->str);
+	free(chunk);
+}
+
+const char *str_preprocess(struct parser_state *state, struct location *loc,
+			   struct scope *scope, const char *x,
+			   struct error_record **erec)
+{
+	struct str_chunk *chunk, *next;
+	struct str_buf *buf;
+	const char *str;
+	int i, j, start;
+	LIST_HEAD(list);
+
+	start = 0;
+	i = 0;
+	while (1) {
+		if (x[i] == '\0') {
+			i++;
+			break;
+		}
+
+		if (x[i] != '$') {
+			i++;
+			continue;
+		}
+
+		if (isdigit(x[++i]))
+			continue;
+
+		j = i;
+		while (1) {
+			if (isalpha(x[i]) ||
+			    isdigit(x[i]) ||
+			    x[i] == '_') {
+				i++;
+				continue;
+			}
+			break;
+		}
+		add_str_chunk(x, start, j-1, &list, false);
+		add_str_chunk(x, j, i, &list, true);
+		start = i;
+	}
+	if (start != i)
+		add_str_chunk(x, start, i, &list, false);
+
+	buf = str_buf_alloc();
+
+	list_for_each_entry_safe(chunk, next, &list, list) {
+		if (chunk->is_sym) {
+			struct symbol *sym;
+
+			sym = symbol_lookup(scope, chunk->str);
+			if (!sym) {
+				sym = symbol_lookup_fuzzy(scope, chunk->str);
+				if (sym) {
+					*erec = error(loc, "unknown identifier '%s'; "
+							   "did you mean identifier '%s'?",
+					              chunk->str, sym->identifier);
+				} else {
+					*erec = error(loc, "unknown identifier '%s'",
+						      chunk->str);
+				}
+				goto err;
+			}
+			str_buf_add(buf, sym->expr->identifier,
+				    strlen(sym->expr->identifier));
+		} else {
+			str_buf_add(buf, chunk->str, chunk->len);
+		}
+		list_del(&chunk->list);
+		free_str_chunk(chunk);
+	}
+
+	str = (char *)buf->str;
+
+	free(buf);
+
+	return (char *)str;
+err:
+	list_for_each_entry_safe(chunk, next, &list, list) {
+		list_del(&chunk->list);
+		free_str_chunk(chunk);
+	}
+	free(buf->str);
+	free(buf);
+
+	return NULL;
+}