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scalafunctionparametersjoern
kiki Shao
kiki Shao

Reputation: 19

Run scala script based on joern, function parameter error！

I want to analyze the if-else structure of the demo.c file through joern and try to write a script with scala, but I found that the running results of scala1 and scala2 are different (the scala1 and scala2 want to express the same meaning). The difference between them is that a function fun is defined in scala1 (actually I want to use this function to achieve other repeated functions), but the result is wrong. Why? Is the parameter type (Traversal [ControlStructure]) of function Fun passed incorrectly?

--------- demo.c ---------
#include <stdio.h>
 
int main () {

   /* local variable definition */
   int a = 100;
 
   /* check the boolean condition */
   if(a>10) {
      if(a>100){
         printf("a > 100");
      }else{
         printf("10<a<100");
      }
   }else if( a <= 10 && a > 0) {
      
      printf("Value of a is 20\n" );
   }else {  
      printf("None of the values is matching\n" );
   }
   printf("Exact value of a is: %d\n", a );

   if ( x > 10 ) {
    printf("111");
   }else{
      printf("222")
   }

   while(x++ < MAX) {
      if(x!=0) {
         int y = 2*x;
         sink(y);
      }
   }
         
   return 0;
}

--------scala script 1--------
open("demo")
def Outermost_layer_branch =     
       cpg.method("main").block.astChildren.isControlStructure.controlStructureType("IF")
def fun(node:Traversal[ControlStructure]){
    def node1 = node.astChildren.isControlStructure.controlStructureType("ELSE")
    println(node1.size)
    // the result is 1, it's right
    def node2 = 
         node1.astChildren.filter(_.isBlock).astChildren.isControlStructure.controlStructureType("IF")
    println(node2.size)
    //the result is 0, it's wrong!! 
}
fun(Outermost_layer_branch.order(3))

--------scala 2--------
open("demo")
def Outermost_layer_branch= 
        cpg.method("main").block.astChildren.isControlStructure.controlStructureType("IF")
def node1 = Outermost_layer_branch.order(3).astChildren.isControlStructure.controlStructureType("ELSE")
println(node1.size)
// the result is 1,and it is right!
def node2 = node1.astChildren.filter(_.isBlock).astChildren.isControlStructure.controlStructureType("IF")
println(node2.size)
// the result is 1,and it is right!

If I want to achieve the correct results through scala1, how can I pass parameters? Or is there any other way?

Upvotes: 1

Views: 207

Answers (1)

kiki Shao
kiki Shao

Reputation: 19

I've fixed the problem！It should be

def fun(node: =>Traversal[ControlStructure])

Upvotes: 1

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