Setuid sandbox unittest: fix environment.

sandbox/linux/suid/client/setuid_sandbox_client_unittest.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 "base/environment.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/string_number_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #include "sandbox/linux/suid/common/sandbox.h"
 #include "setuid_sandbox_client.h"
 
 namespace sandbox {
 
 TEST(SetuidSandboxClient, SetupLaunchEnvironment) {
   const char kTestValue[] = "This is a test";
   scoped_ptr<base::Environment> env(base::Environment::Create());
   EXPECT_TRUE(env != NULL);
 
+  std::string saved_ld_preload;
+  bool environment_had_ld_preload;
+  // First, back-up the real LD_PRELOAD if any.
+  environment_had_ld_preload = env->GetVar("LD_PRELOAD", &saved_ld_preload);
   // Setup environment variables to save or not save.
   EXPECT_TRUE(env->SetVar("LD_PRELOAD", kTestValue));
   EXPECT_TRUE(env->UnSetVar("LD_ORIGIN_PATH"));
 
   scoped_ptr<SetuidSandboxClient>
       sandbox_client(SetuidSandboxClient::Create());
   EXPECT_TRUE(sandbox_client != NULL);
 
   // Make sure the environment is clean.
   EXPECT_TRUE(env->UnSetVar(kSandboxEnvironmentApiRequest));
   EXPECT_TRUE(env->UnSetVar(kSandboxEnvironmentApiProvides));
 
   sandbox_client->SetupLaunchEnvironment();
 
   // Check if the requested API environment was set.
   std::string api_request;
   EXPECT_TRUE(env->GetVar(kSandboxEnvironmentApiRequest, &api_request));
   int api_request_num;
   EXPECT_TRUE(base::StringToInt(api_request, &api_request_num));
   EXPECT_EQ(api_request_num, kSUIDSandboxApiNumber);
 
   // Now check if LD_PRELOAD was saved to SANDBOX_LD_PRELOAD.
   std::string sandbox_ld_preload;
   EXPECT_TRUE(env->GetVar("SANDBOX_LD_PRELOAD", &sandbox_ld_preload));
   EXPECT_EQ(sandbox_ld_preload, kTestValue);
 
   // Check that LD_ORIGIN_PATH was not saved.
   EXPECT_FALSE(env->HasVar("SANDBOX_LD_ORIGIN_PATH"));
+
+  // We should not forget to restore LD_PRELOAD at the end, or this environment
+  // variable will affect the next running tests!
+  if (environment_had_ld_preload) {
+    EXPECT_TRUE(env->SetVar("LD_PRELOAD", saved_ld_preload));
+  } else {
+    EXPECT_TRUE(env->UnSetVar("LD_PRELOAD"));
+  }
 }
 
 TEST(SetuidSandboxClient, SandboxedClientAPI) {
   scoped_ptr<base::Environment> env(base::Environment::Create());
   EXPECT_TRUE(env != NULL);
 
   scoped_ptr<SetuidSandboxClient>
       sandbox_client(SetuidSandboxClient::Create());
   EXPECT_TRUE(sandbox_client != NULL);
 
@@ skipping 13 matching lines @@
   // Forge an incorrect API version and check.
   EXPECT_TRUE(env->SetVar(kSandboxEnvironmentApiProvides,
               base::IntToString(kSUIDSandboxApiNumber + 1)));
   EXPECT_FALSE(sandbox_client->IsSuidSandboxUpToDate());
   // We didn't go through the actual sandboxing mechanism as it is
   // very hard in a unit test.
   EXPECT_FALSE(sandbox_client->IsSandboxed());
 }
 
 }  // namespace sandbox