Merge pull request #5104 from opensourcerouting/route-map-nbv2

[mirror_frr.git] / lib / command_parse.y

diff --git a/lib/command_parse.y b/lib/command_parse.y
index 1b304a98b2b151dcaa51084d98383b7c340a31cc..5dc19d2c9bffed70649706cb9902f1d9e6f59e16 100644 (file)
--- a/lib/command_parse.y
+++ b/lib/command_parse.y
@@ -46,6 +46,7 @@
 %code requires {
   #include "config.h"
 
+  #include <stdbool.h>
   #include <stdlib.h>
   #include <string.h>
   #include <ctype.h>
@@ -83,7 +84,7 @@
   struct parser_ctx {
     yyscan_t scanner;
 
-    struct cmd_element *el;
+    const struct cmd_element *el;
 
     struct graph *graph;
     struct graph_node *currnode;
@@ -140,6 +141,8 @@
   static void
   cleanup (struct parser_ctx *ctx);
 
+  static void loopcheck(struct parser_ctx *ctx, struct subgraph *sg);
+
   #define scanner ctx->scanner
 }
 
@@ -335,6 +338,7 @@ selector: '{' selector_seq_seq '}' varname_token
    * just use [{a|b}] if neccessary, that will work perfectly fine, and reason
    * #1 is good enough to keep it this way. */
 
+  loopcheck(ctx, &$$);
   cmd_token_varname_set ($2.end->data, $4);
   XFREE (MTYPE_LEX, $4);
 };
@@ -375,7 +379,7 @@ selector: '[' selector_seq_seq ']' varname_token
 DEFINE_MTYPE(LIB, LEX, "Lexer token (temporary)")
 
 void
-cmd_graph_parse (struct graph *graph, struct cmd_element *cmd)
+cmd_graph_parse (struct graph *graph, const struct cmd_element *cmd)
 {
   struct parser_ctx ctx = { .graph = graph, .el = cmd };
 
@@ -396,6 +400,38 @@ cmd_graph_parse (struct graph *graph, struct cmd_element *cmd)
 
 /* parser helper functions */
 
+static bool loopcheck_inner(struct graph_node *start, struct graph_node *node,
+                           struct graph_node *end, size_t depth)
+{
+       size_t i;
+       bool ret;
+
+       /* safety check */
+       if (depth++ == 64)
+               return true;
+
+       for (i = 0; i < vector_active(node->to); i++) {
+               struct graph_node *next = vector_slot(node->to, i);
+               struct cmd_token *tok = next->data;
+
+               if (next == end || next == start)
+                       return true;
+               if (tok->type < SPECIAL_TKN)
+                       continue;
+               ret = loopcheck_inner(start, next, end, depth);
+               if (ret)
+                       return true;
+       }
+       return false;
+}
+
+static void loopcheck(struct parser_ctx *ctx, struct subgraph *sg)
+{
+       if (loopcheck_inner(sg->start, sg->start, sg->end, 0))
+               zlog_err("FATAL: '%s': {} contains an empty path! Use [{...}]",
+                        ctx->el->string);
+}
+
 void
 yyerror (CMD_YYLTYPE *loc, struct parser_ctx *ctx, char const *msg)
 {
@@ -449,11 +485,11 @@ terminate_graph (CMD_YYLTYPE *locp, struct parser_ctx *ctx,
 {
   // end of graph should look like this
   // * -> finalnode -> END_TKN -> cmd_element
-  struct cmd_element *element = ctx->el;
+  const struct cmd_element *element = ctx->el;
   struct graph_node *end_token_node =
     new_token_node (ctx, END_TKN, CMD_CR_TEXT, "");
   struct graph_node *end_element_node =
-    graph_new_node (ctx->graph, element, NULL);
+    graph_new_node (ctx->graph, (void *)element, NULL);
 
   if (ctx->docstr && strlen (ctx->docstr) > 1) {
     zlog_debug ("Excessive docstring while parsing '%s'", ctx->el->string);