Refactored ErrorCode into it's own class

sandbox/linux/seccomp-bpf/errorcode.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
+
+
+namespace playground2 {
+
+ErrorCode::ErrorCode(int err) {
+  switch (err) {
+  case ERR_INVALID:
+    // We allow the default constructor, as it makes the ErrorCode class
+    // much easier to use. But if we ever encounter an invalid ErrorCode
+    // when compiling a BPF filter, we deliberately generate an invalid
+    // program that will get flagged both by our Verifier class and by
+    // the Linux kernel.
+    err_ = SECCOMP_RET_INVALID;
+    errorType_ = ET_INVALID;
+    break;
+  case ERR_ALLOWED:
+    err_ = SECCOMP_RET_ALLOW;
+    errorType_ = ET_SIMPLE;
+    break;
+  case ERR_MIN_ERRNO ... ERR_MAX_ERRNO:
+    err_ = SECCOMP_RET_ERRNO + err;
+    errorType_ = ET_SIMPLE;
+    break;
+  default:
+    die("Invalid use of ErrorCode object");
+  }
+}
+
+ErrorCode::ErrorCode(ErrorCode::TrapFnc fnc, const void *aux, uint16_t id) :
+  errorType_(ET_TRAP),

[jln (very slow on Chromium), 2012/07/27 19:46:30]

Initializer lists should be indented 4 spaces, the colon should be on the first
initializer line.

+  fnc_(fnc),
+  aux_(const_cast<void *>(aux)),
+  err_(SECCOMP_RET_TRAP + id) {
+}
+
+  ErrorCode::ErrorCode(int argno, ArgType width, Operation op, uint64_t value,
+                     const ErrorCode *passed, const ErrorCode *failed) :
+  errorType_(ET_COND),

[jln (very slow on Chromium), 2012/07/27 19:46:30]

Same here.

+  value_(value),
+  argno_(argno),
+  width_(width),
+  op_(op),
+  passed_(passed),
+  failed_(failed),
+  err_(SECCOMP_RET_INVALID) {
+  if (op < 0 || op >= OP_NUM_OPS) {
+    die("Invalid opcode in BPF sandbox rules");
+  }
+}
+
+bool ErrorCode::isEqual(const ErrorCode &err) const {
+  if (errorType_ == ET_INVALID || err.errorType_ == ET_INVALID) {
+    die("Dereferencing invalid ErrorCode");
+  }
+  if (errorType_ != err.errorType_) {
+    return false;
+  }
+  if (errorType_ == ET_SIMPLE || errorType_ == ET_TRAP) {
+    return err_ == err.err_;
+  } else if (errorType_ == ET_COND) {
+    return value_   == err.value_   &&
+           argno_   == err.argno_   &&
+           width_   == err.width_   &&
+           op_      == err.op_      &&
+           passed_->isEqual(*err.passed_) &&
+           failed_->isEqual(*err.failed_);
+  } else {
+    die("Corrupted ErrorCode");
+  }
+}
+
+bool ErrorCode::lessThan(const ErrorCode& err) const {

[jln (very slow on Chromium), 2012/07/27 19:46:30]

This is quit "artificial". Do you mind adding a comment explaining why this is
needed?

+  if (errorType_ == ET_INVALID || err.errorType_ == ET_INVALID) {
+    die("Dereferencing invalid ErrorCode");
+  }
+  if (errorType_ != err.errorType_) {
+    return errorType_ < err.errorType_;
+  } else {
+    if (errorType_ == ET_SIMPLE || errorType_ == ET_TRAP) {
+      return err_ < err.err_;
+    } else if (errorType_ == ET_COND) {
+      if (value_ != err.value_) {
+        return value_ < err.value_;
+      } else if (argno_ != err.argno_) {
+        return argno_ < err.argno_;
+      } else if (width_ != err.width_) {
+        return width_ < err.width_;
+      } else if (op_ != err.op_) {
+        return op_ < err.op_;
+      } else if (!passed_->isEqual(*err.passed_)) {
+        return passed_->lessThan(*err.passed_);

[jln (very slow on Chromium), 2012/07/27 19:46:30]

Do you want to add a CHECK here, to check that &err != passed_ && &err !=
failed_ or something along those lines ?

+      } else if (!failed_->isEqual(*err.failed_)) {
+        return failed_->lessThan(*err.failed_);
+      } else {
+        return false;
+      }
+    } else {
+      die("Corrupted ErrorCode");
+    }
+  }
+}
+
+void ErrorCode::die(const char *msg) {
+  Sandbox::die(msg);
+}
+
+}  // namespace