Create a portability header for working with environment variables

Summary:Because `extern char** environ` is not the correct way to access environ on Windows.
This also implements setenv and unsetenv for Windows, which means that TestUtils no longer needs to be disabled for the Windows build.

Reviewed By: mzlee

Differential Revision: D2973704

fb-gh-sync-id: 84db7db3494cf183fcbcc25063cb0482ef84ebf4
shipit-source-id: 84db7db3494cf183fcbcc25063cb0482ef84ebf4

diff --git a/folly/Makefile.am b/folly/Makefile.am
index 586dcc5a3960cc6317db5f5c0c6ee98c9e9cef46..74f465f7fd0b277cf86bb6b154ad85ac5b495ad4 100644 (file)
--- a/folly/Makefile.am
+++ b/folly/Makefile.am
@@ -265,6 +265,7 @@ nobase_follyinclude_HEADERS = \
        PicoSpinLock.h \
        Portability.h \
        portability/Constexpr.h \
+       portability/Environment.h \
        portability/Syscall.h \
        portability/SysUio.h \
        Preprocessor.h \
@@ -390,6 +391,7 @@ libfolly_la_SOURCES = \
        detail/MemoryIdler.cpp \
        MacAddress.cpp \
        MemoryMapping.cpp \
+       portability/Environment.cpp \
        Random.cpp \
        SafeAssert.cpp \
        SharedMutex.cpp \

diff --git a/folly/Subprocess.cpp b/folly/Subprocess.cpp
index a737c831d1fa6dd12312fb0e330ffb03de103b0c..de5b109e33a6566e179b37ceac010650f5a2460a 100644 (file)
--- a/folly/Subprocess.cpp
+++ b/folly/Subprocess.cpp
@@ -42,8 +42,7 @@
 #include <folly/ScopeGuard.h>
 #include <folly/String.h>
 #include <folly/io/Cursor.h>
-
-extern char** environ;
+#include <folly/portability/Environment.h>
 
 constexpr int kExecFailure = 127;
 constexpr int kChildFailure = 126;

diff --git a/folly/experimental/TestUtil.cpp b/folly/experimental/TestUtil.cpp
index b9c68ad1bb5a458728c3c620bf9cbeed3d6f8da4..e1f2010bc21d77d10de8769c812613ac7451cde6 100644 (file)
--- a/folly/experimental/TestUtil.cpp
+++ b/folly/experimental/TestUtil.cpp
@@ -27,10 +27,7 @@
 #include <folly/File.h>
 #include <folly/FileUtil.h>
 #include <folly/String.h>
-
-#ifndef _MSC_VER
-extern char** environ;
-#endif
+#include <folly/portability/Environment.h>
 
 namespace folly {
 namespace test {

diff --git a/folly/portability/Environment.cpp b/folly/portability/Environment.cpp
new file mode 100755 (executable)
index 0000000..34f9121
--- /dev/null
+++ b/folly/portability/Environment.cpp
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2016 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <folly/portability/Environment.h>
+
+#ifdef _WIN32
+#include <Windows.h>
+
+extern "C" {
+
+int setenv(const char* name, const char* value, int overwrite) {
+  if (overwrite == 0 && getenv(name) != nullptr) {
+    return 0;
+  }
+
+  // _putenv_s deletes entries if the value is an empty string,
+  // so we have to call the windows API function to safely assign
+  // these.
+  if (SetEnvironmentVariableA(name, value) != 0) {
+    errno = EINVAL;
+    return -1;
+  }
+  return 0;
+}
+
+int unsetenv(const char* name) {
+  if (_putenv_s(name, "") != 0) {
+    return -1;
+  }
+  return 0;
+}
+}
+#endif

diff --git a/folly/portability/Environment.h b/folly/portability/Environment.h
new file mode 100755 (executable)
index 0000000..17e756a
--- /dev/null
+++ b/folly/portability/Environment.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2016 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stdlib.h>
+
+extern "C" {
+#ifndef _WIN32
+extern char** environ;
+#else
+int setenv(const char* name, const char* value, int overwrite);
+int unsetenv(const char* name);
+#endif
+}