Kamailio compatibility changes: replace_build

List of changes:
 * Add support for pseudo variables
 * Create a static buffer allocated on the stack that will be used to
   print the resulting string, we no longer can determine the final
   size of the result in advance because of pseudo-variable support and
   thus we print to a fixed-size buffer and copy the result into a
   dynamically allocated buffer when done.
 * Define macro RBUF_APPEND which is used to add text to the static
   buffer, the macro checks if there is enough space in the buffer
   before each write
 * Remove the call to replace_len at the beginning of the function
 * Replace all occurrences of memcpy(...) and dest+=... with
   RBUF_APPEND
 * At the end create a dynamically allocated buffer for the result and
   copy the string from the static buffer into the dynamic buffer.

re.c

@@ -381,30 +381,30 @@ static int replace_build(const char* match, int nmatch, regmatch_t* pmatch,
 {
 	int r;
 	str* uri;
+	pv_value_t sv;
 	char* p;
 	char* dest;
 	char* end;
 	int size;
-	
-	rpl->len=replace_len(match, nmatch, pmatch, se, msg);
-	if (rpl->len==0){
-		rpl->s=0; /* empty string */
-		return 0;
-	}
-	rpl->s=pkg_malloc(rpl->len);
-	if (rpl->s==0){
-		LOG(L_ERR, "ERROR: replace_build: out of mem (rpl)\n");
-		goto error;
-	}
+	static char rbuf[REPLACE_BUFFER_SIZE];
+
+#define RBUF_APPEND(dst, src, size) \
+	if ((dst) - rbuf + (size) >= REPLACE_BUFFER_SIZE - 1) {	\
+		ERR("replace_build: Buffer too small\n");			\
+		goto error;											\
+	}														\
+	memcpy((dst), (src), (size));							\
+	(dst) += (size);
+
 	p=se->replacement.s;
 	end=p+se->replacement.len;
-	dest=rpl->s;
+	dest=rbuf;
+	
 	for (r=0; r<se->n_escapes; r++){
 		/* copy the unescaped parts */
 		size=se->replacement.s+se->replace[r].offset-p;
-		memcpy(dest, p, size);
+		RBUF_APPEND(dest, p, size);
 		p+=size+se->replace[r].size;
-		dest+=size;
 		switch(se->replace[r].type){
 			case REPLACE_NMATCH:
 				if ((se->replace[r].u.nmatch<nmatch)&&(
@@ -412,15 +412,13 @@ static int replace_build(const char* match, int nmatch, regmatch_t* pmatch,
 						/* do the replace */
 						size=pmatch[se->replace[r].u.nmatch].rm_eo-
 								pmatch[se->replace[r].u.nmatch].rm_so;
-						memcpy(dest, 
-								match+pmatch[se->replace[r].u.nmatch].rm_so,
-								size);
-						dest+=size;
+						RBUF_APPEND(dest, 
+									match+pmatch[se->replace[r].u.nmatch].rm_so,
+									size);
 				};
 				break;
 			case REPLACE_CHAR:
-				*dest=se->replace[r].u.c;
-				dest++;
+				RBUF_APPEND(dest, &se->replace[r].u.c, 1);
 				break;
 			case REPLACE_URI:
 				if (msg->first_line.type!=SIP_REQUEST){
@@ -430,8 +428,14 @@ static int replace_build(const char* match, int nmatch, regmatch_t* pmatch,
 				}
 				uri= (msg->new_uri.s)?(&msg->new_uri):
 					(&msg->first_line.u.request.uri);
-				memcpy(dest, uri->s, uri->len);
-				dest+=uri->len;
+				RBUF_APPEND(dest, uri->s, uri->len);
+				break;
+			case REPLACE_SPEC:
+				if(pv_get_spec_value(msg, &se->replace[r].u.spec, &sv)!=0) {
+					ERR("replace_build: item substitution returned error\n");
+					break; /* ignore, we can continue */
+				}
+				RBUF_APPEND(dest, sv.rs.s, sv.rs.len);
 				break;
 			default:
 				LOG(L_CRIT, "BUG: replace_build: unknown type %d\n", 
@@ -439,7 +443,13 @@ static int replace_build(const char* match, int nmatch, regmatch_t* pmatch,
 				/* ignore it */
 		}
 	}
-	memcpy(dest, p, end-p);
+	RBUF_APPEND(dest, p, end-p);
+	rpl->len = dest - rbuf;
+	if ((rpl->s = pkg_malloc(rpl->len)) == NULL) {
+		ERR("replace_build: Out of pkg memory\n");
+		goto error;
+	}
+	memcpy(rpl->s, rbuf, rpl->len);
 	return 0;
 error:
 	return -1;