1 files changed, 185 insertions, 0 deletions
diff --git a/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/ErrnoTesterChecker.cpp b/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/ErrnoTesterChecker.cpp
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index 000000000000..c46ebee0c94f
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+++ b/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/ErrnoTesterChecker.cpp
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+//=== ErrnoTesterChecker.cpp ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines ErrnoTesterChecker, which is used to test functionality of the
+// errno_check API.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ErrnoModeling.h"
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include <optional>
+
+using namespace clang;
+using namespace ento;
+using namespace errno_modeling;
+
+namespace {
+
+class ErrnoTesterChecker : public Checker<eval::Call> {
+public:
+  bool evalCall(const CallEvent &Call, CheckerContext &C) const;
+
+private:
+  /// Evaluate function \code void ErrnoTesterChecker_setErrno(int) \endcode.
+  /// Set value of \c errno to the argument.
+  static void evalSetErrno(CheckerContext &C, const CallEvent &Call);
+  /// Evaluate function \code int ErrnoTesterChecker_getErrno() \endcode.
+  /// Return the value of \c errno.
+  static void evalGetErrno(CheckerContext &C, const CallEvent &Call);
+  /// Evaluate function \code int ErrnoTesterChecker_setErrnoIfError() \endcode.
+  /// Simulate a standard library function tha returns 0 on success and 1 on
+  /// failure. On the success case \c errno is not allowed to be used (may be
+  /// undefined). On the failure case \c errno is set to a fixed value 11 and
+  /// is not needed to be checked.
+  static void evalSetErrnoIfError(CheckerContext &C, const CallEvent &Call);
+  /// Evaluate function \code int ErrnoTesterChecker_setErrnoIfErrorRange()
+  /// \endcode. Same as \c ErrnoTesterChecker_setErrnoIfError but \c errno is
+  /// set to a range (to be nonzero) at the failure case.
+  static void evalSetErrnoIfErrorRange(CheckerContext &C,
+                                       const CallEvent &Call);
+  /// Evaluate function \code int ErrnoTesterChecker_setErrnoCheckState()
+  /// \endcode. This function simulates the following:
+  /// - Return 0 and leave \c errno with undefined value.
+  ///   This is the case of a successful standard function call.
+  ///   For example if \c ftell returns not -1.
+  /// - Return 1 and sets \c errno to a specific error code (1).
+  ///   This is the case of a failed standard function call.
+  ///   The function indicates the failure by a special return value
+  ///   that is returned only at failure.
+  ///   \c errno can be checked but it is not required.
+  ///   For example if \c ftell returns -1.
+  /// - Return 2 and may set errno to a value (actually it does not set it).
+  ///   This is the case of a standard function call where the failure can only
+  ///   be checked by reading from \c errno. The value of \c errno is changed by
+  ///   the function only at failure, the user should set \c errno to 0 before
+  ///   the call (\c ErrnoChecker does not check for this rule).
+  ///   \c strtol is an example of this case, if it returns \c LONG_MIN (or
+  ///   \c LONG_MAX). This case applies only if \c LONG_MIN or \c LONG_MAX is
+  ///   returned, otherwise the first case in this list applies.
+  static void evalSetErrnoCheckState(CheckerContext &C, const CallEvent &Call);
+
+  using EvalFn = std::function<void(CheckerContext &, const CallEvent &)>;
+  const CallDescriptionMap<EvalFn> TestCalls{
+      {{{"ErrnoTesterChecker_setErrno"}, 1}, &ErrnoTesterChecker::evalSetErrno},
+      {{{"ErrnoTesterChecker_getErrno"}, 0}, &ErrnoTesterChecker::evalGetErrno},
+      {{{"ErrnoTesterChecker_setErrnoIfError"}, 0},
+       &ErrnoTesterChecker::evalSetErrnoIfError},
+      {{{"ErrnoTesterChecker_setErrnoIfErrorRange"}, 0},
+       &ErrnoTesterChecker::evalSetErrnoIfErrorRange},
+      {{{"ErrnoTesterChecker_setErrnoCheckState"}, 0},
+       &ErrnoTesterChecker::evalSetErrnoCheckState}};
+};
+
+} // namespace
+
+void ErrnoTesterChecker::evalSetErrno(CheckerContext &C,
+                                      const CallEvent &Call) {
+  C.addTransition(setErrnoValue(C.getState(), C.getLocationContext(),
+                                Call.getArgSVal(0), Irrelevant));
+}
+
+void ErrnoTesterChecker::evalGetErrno(CheckerContext &C,
+                                      const CallEvent &Call) {
+  ProgramStateRef State = C.getState();
+
+  std::optional<SVal> ErrnoVal = getErrnoValue(State);
+  assert(ErrnoVal && "Errno value should be available.");
+  State =
+      State->BindExpr(Call.getOriginExpr(), C.getLocationContext(), *ErrnoVal);
+
+  C.addTransition(State);
+}
+
+void ErrnoTesterChecker::evalSetErrnoIfError(CheckerContext &C,
+                                             const CallEvent &Call) {
+  ProgramStateRef State = C.getState();
+  SValBuilder &SVB = C.getSValBuilder();
+
+  ProgramStateRef StateSuccess = State->BindExpr(
+      Call.getOriginExpr(), C.getLocationContext(), SVB.makeIntVal(0, true));
+  StateSuccess = setErrnoState(StateSuccess, MustNotBeChecked);
+
+  ProgramStateRef StateFailure = State->BindExpr(
+      Call.getOriginExpr(), C.getLocationContext(), SVB.makeIntVal(1, true));
+  StateFailure = setErrnoValue(StateFailure, C, 11, Irrelevant);
+
+  C.addTransition(StateSuccess);
+  C.addTransition(StateFailure);
+}
+
+void ErrnoTesterChecker::evalSetErrnoIfErrorRange(CheckerContext &C,
+                                                  const CallEvent &Call) {
+  ProgramStateRef State = C.getState();
+  SValBuilder &SVB = C.getSValBuilder();
+
+  ProgramStateRef StateSuccess = State->BindExpr(
+      Call.getOriginExpr(), C.getLocationContext(), SVB.makeIntVal(0, true));
+  StateSuccess = setErrnoState(StateSuccess, MustNotBeChecked);
+
+  ProgramStateRef StateFailure = State->BindExpr(
+      Call.getOriginExpr(), C.getLocationContext(), SVB.makeIntVal(1, true));
+  DefinedOrUnknownSVal ErrnoVal = SVB.conjureSymbolVal(
+      nullptr, Call.getOriginExpr(), C.getLocationContext(), C.blockCount());
+  StateFailure = StateFailure->assume(ErrnoVal, true);
+  assert(StateFailure && "Failed to assume on an initial value.");
+  StateFailure =
+      setErrnoValue(StateFailure, C.getLocationContext(), ErrnoVal, Irrelevant);
+
+  C.addTransition(StateSuccess);
+  C.addTransition(StateFailure);
+}
+
+void ErrnoTesterChecker::evalSetErrnoCheckState(CheckerContext &C,
+                                                const CallEvent &Call) {
+  ProgramStateRef State = C.getState();
+  SValBuilder &SVB = C.getSValBuilder();
+
+  ProgramStateRef StateSuccess = State->BindExpr(
+      Call.getOriginExpr(), C.getLocationContext(), SVB.makeIntVal(0, true));
+  StateSuccess = setErrnoState(StateSuccess, MustNotBeChecked);
+
+  ProgramStateRef StateFailure1 = State->BindExpr(
+      Call.getOriginExpr(), C.getLocationContext(), SVB.makeIntVal(1, true));
+  StateFailure1 = setErrnoValue(StateFailure1, C, 1, Irrelevant);
+
+  ProgramStateRef StateFailure2 = State->BindExpr(
+      Call.getOriginExpr(), C.getLocationContext(), SVB.makeIntVal(2, true));
+  StateFailure2 = setErrnoValue(StateFailure2, C, 2, MustBeChecked);
+
+  C.addTransition(StateSuccess,
+                  getErrnoNoteTag(C, "Assuming that this function succeeds but "
+                                     "sets 'errno' to an unspecified value."));
+  C.addTransition(StateFailure1);
+  C.addTransition(
+      StateFailure2,
+      getErrnoNoteTag(C, "Assuming that this function returns 2. 'errno' "
+                         "should be checked to test for failure."));
+}
+
+bool ErrnoTesterChecker::evalCall(const CallEvent &Call,
+                                  CheckerContext &C) const {
+  const EvalFn *Fn = TestCalls.lookup(Call);
+  if (Fn) {
+    (*Fn)(C, Call);
+    return C.isDifferent();
+  }
+  return false;
+}
+
+void ento::registerErrnoTesterChecker(CheckerManager &Mgr) {
+  Mgr.registerChecker<ErrnoTesterChecker>();
+}
+
+bool ento::shouldRegisterErrnoTesterChecker(const CheckerManager &Mgr) {
+  return true;
+}