[clang] [analyzer] Modernize, improve and promote chroot checker (PR #117791)

[Balazs Benics via cfe-commits]

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@@ -104,15 +146,35 @@ void ChrootChecker::evalChdir(const CallEvent &Call, CheckerContext &C) const {
     R = R->StripCasts();
     if (const StringRegion* StrRegion= dyn_cast<StringRegion>(R)) {
       const StringLiteral* Str = StrRegion->getStringLiteral();
-      if (Str->getString() == "/")
-        state = Mgr.addGDM(state, ChrootChecker::getTag(),
-                           (void*) JAIL_ENTERED);
+      if (Str->getString() == "/") {
+        state = state->set<ChrootState>(JAIL_ENTERED);
+      }
     }
   }
 
   C.addTransition(state);
 }
 
+const ExplodedNode *ChrootChecker::getAcquisitionSite(const ExplodedNode *N,
+                                                      CheckerContext &C) {
+  ProgramStateRef State = N->getState();
+  // When bug type is resource leak, exploded node N may not have state info
+  // for leaked file descriptor, but predecessor should have it.
+  if (!State->get<ChrootCall>())
+    N = N->getFirstPred();
+
+  const ExplodedNode *Pred = N;
+  while (N) {
+    State = N->getState();
+    if (!State->get<ChrootCall>())
+      return Pred;
+    Pred = N;
+    N = N->getFirstPred();
+  }
----------------
steakhal wrote:

TBH the node you really want to find is where you have `ChrootCall` set, but in the pred node it's not yet set.

This loop would accept a node if its parent and also its parent don't have `ChrootCall` set - which is not exactly what we want.

BTW I'm surprised to have this egraph walk, which is usually done by BugReportVisitors. In such a visitor you would have an easier time for implementing this.

https://github.com/llvm/llvm-project/pull/117791