Augmentation Directives

Augmentation Directives are CPGQL Directives which extend a Code Property Graph with nodes, properties and edges.

Take the following simple program named X42:

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

int main(int argc, char *argv[]) {

if (argc > 1 && strcmp(argv[1], "42") == 0) {

fprintf(stderr, "It depends!\n");

exit(42);

}

printf("What is the meaning of life?\n");

exit(0);

}

newTagNode

newTagNode is an Augmentation Directive that adds tags with user-defined keys to the nodes that are part of the traversal they're suffixing. It works together with the store CPGQL Component which creates the actual nodes representing the tags, and the run.commit which merges those nodes in the active Code Property Graph.

Say for example that you'd like to add tags to all the nodes of X42's Code Property Graph that represent calls to exit. That is, these two:

// list all CALL nodes in the X42 program with the string "exit" in their CALL property

joern> cpg.call.name("exit").code.l

res0: List[String] = List("exit(0)", "exit(42)")

And say that you'd like to use the key MY_KIND_OF_EXIT for the tags you want to create:

// create tags with the key MY_KIND_OF_EXIT for all CALL nodes which have the string "exit" in the value of their NAME property

joern> cpg.call.name("exit").newTagNode("MY_KIND_OF_EXIT").store

// apply the diffgraph to the currently active Code Property Graph

joern> run.commit

2020-07-02 14:07:02.041 [main] INFO Enhancement io.shiftleft.console.Commit$$anon$1 completed in 0 milliseconds

The graph has been modified. You may want to use the `save` command to persist changes to disk. All changes will also be saved collectively on exit

res1: Cpg = io.shiftleft.codepropertygraph.Cpg@97c920b

// list the newly created tags

joern> cpg.tag.name("MY_KIND_OF_EXIT").l

res2: List[nodes.Tag] = List(

Tag(id -> 42L, name -> "MY_KIND_OF_EXIT", value -> ""),

Tag(id -> 41L, name -> "MY_KIND_OF_EXIT", value -> "")

)

// list the CODE property of all CALL nodes attached to the newly created tags

joern> cpg.tag.name("MY_KIND_OF_EXIT").call.code.l

res3: List[String] = List("exit(42)", "exit(0)")

newTagNodePair

newTagNodePair is very similar to newTagNode: it is an Augmentation Directive that adds tags with user-defined keys and user-defined values to the nodes that are part of the traversal they're suffixing. It also works together with store and run.commit, but you can specify both a key and a value for the nodes created:

joern> cpg.call.name("exit").newTagNodePair("MY_OTHER_KIND_OF_EXIT", "MY_VALUE").store

joern> run.commit

2020-07-02 14:07:02.041 [main] INFO Enhancement io.shiftleft.console.Commit$$anon$1 completed in 0 milliseconds

The graph has been modified. You may want to use the `save` command to persist changes to disk. All changes will also be saved collectively on exit

res1: Cpg = io.shiftleft.codepropertygraph.Cpg@97c920b

joern> cpg.tag.name("MY_OTHER_KIND_OF_EXIT").l

res2: List[nodes.Tag] = List(

Tag(id -> 44L, name -> "MY_OTHER_KIND_OF_EXIT", value -> "MY_VALUE"),

Tag(id -> 43L, name -> "MY_OTHER_KIND_OF_EXIT", value -> "MY_VALUE")

)

joern> cpg.tag.value("MY_VALUE").call.code.l

res3: List[String] = List("exit(42)", "exit(0)")