Refactor multipart parsing

zet.dpi.c

@@ -961,6 +961,15 @@ static char *next_line(char *str) {
 	return nextline;
 }
 
+static char *parse_header(char *line) {
+	char *value = strchr(line, ':');
+	if (value != NULL) {
+		*value++ = '\0';
+		while (*value == ' ') value++;
+	}
+	return value;
+}
+
 static int http_serve_index(struct http_request *req) {
 	write_buf(req->fd, "HTTP/1.0 200 OK\r\nConnection: close\r\n\r\n");
 	close(req->fd);
@@ -990,42 +999,48 @@ static int parse_multipart(struct http_request *req) {
 		req->len = len;
 	}
 	req->data[req->len] = '\0';
-	char *boundary_start = NULL;
-	while (req->len > 0) {
-		boundary_start = strstr(req->data, req->multipart_boundary);
-		if (boundary_start == NULL) return -1;
-		boundary_start += boundary_len;
-		char *line = boundary_start;
+
+	// iterate through parts
+	char *part, *next;
+	const char *boundary = req->multipart_boundary;
+	for (part = strstr(req->data, boundary); part != NULL; part = next) {
+		part += boundary_len;
+		if (part[0] == '-' && part[1] == '-') break; // end of parts
+		if (*part == '\r') part++;
+		if (*part == '\n') part++;
+		next = strstr(part, req->multipart_boundary);
+		char *end = next;
+		if (end != NULL) {
+			if (end[-1] == '\n') end--;
+			if (end[-1] == '\r') end--;
+			*end = '\0';
+		}
+
+		// iterate through headers in part
+		char *line, *nextline;
 		char *cdisp = NULL;
-		bool is_text = false;
-		if (*line == '\r') line++;
-		if (*line == '\n') line++;
-		char *nextline;
-		while (line != NULL) {
+		for (line = part; line != NULL; line = nextline) {
 			nextline = next_line(line);
-			if (!line[0]) break;
+			if (!*line) break; // end of headers
 			char *name = line;
-			char *value = strchr(line, ':');
-			if (value != NULL) {
-				*value++ = '\0';
-				while (*value == ' ') value++;
-			}
+			char *value = parse_header(line);
 			if (!strncmp(name, "Content-Disposition", 3)) cdisp = value;
-			line = nextline;
 		}
-		if (cdisp != NULL && !strcmp(cdisp, "form-data; name=\"text\"")) {
-			is_text = true;
+		char *name = NULL;
+		if (cdisp != NULL && !strncmp(cdisp, "form-data; name=\"", 17)) {
+			name = cdisp + 17;
+			char *end = strchr(name, '"');
+			if (end != NULL) *end = '\0';
 		}
-		req->len -= nextline - req->data;
-		req->data = nextline;
 
-		char *end = strstr(nextline, req->multipart_boundary);
-		if (end == NULL || strncmp(end + boundary_len, "--", 2)) return -1;
-		if (end[-1] == '\n') end--;
-		if (end[-1] == '\r') end--;
-		*end = '\0';
-		req->len = end - nextline;
-		if (is_text) break;
+		// handle part body
+		char *body = nextline;
+		if (body == NULL) continue;
+
+		if (!strcmp(name, "text")) {
+			req->data = body;
+			req->len = end == NULL ? strlen(body) : end - body;
+		}
 	}
 	return 0;
 }
@@ -1181,11 +1196,7 @@ static int handle_http_client(int fd, int firstchar) {
 		nextline = next_line(line);
 		if (!line[0]) break;
 		char *name = line;
-		char *value = strchr(line, ':');
-		if (value != NULL) {
-			*value++ = '\0';
-			while (*value == ' ') value++;
-		}
+		char *value = parse_header(line);
 		if (!strncmp(name, "Host", 3)) req.host = value;
 		else if (!strncmp(name, "Referer", 7)) req.referer = value;
 		else if (!strncmp(name, "Content-Length", 14)) req.content_length = atoi(value);