Revert r180082 and add a test for SetEnv function

llvm-svn: 180098

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -130,6 +130,7 @@ void DisableCoreDumper();
 void DumpProcessMap();
 bool FileExists(const char *filename);
 const char *GetEnv(const char *name);
+bool SetEnv(const char *name, const char *value);
 const char *GetPwd();
 u32 GetUid();
 void ReExec();

compiler-rt/lib/sanitizer_common/sanitizer_linux.cc

@@ -264,6 +264,20 @@ const char *GetEnv(const char *name) {
   return 0;  // Not found.
 }
 
+// Does not compile for Go because dlsym() requires -ldl
+#ifndef SANITIZER_GO
+bool SetEnv(const char *name, const char *value) {
+  void *f = dlsym(RTLD_NEXT, "setenv");
+  if (f == 0)
+    return false;
+  typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
+  setenv_ft setenv_f;
+  CHECK_EQ(sizeof(setenv_f), sizeof(f));
+  internal_memcpy(&setenv_f, &f, sizeof(f));
+  return setenv_f(name, value, 1) == 0;
+}
+#endif
+
 #ifdef __GLIBC__
 
 extern "C" {

compiler-rt/lib/sanitizer_common/tests/sanitizer_linux_test.cc

@@ -20,6 +20,7 @@
 
 #include <pthread.h>
 #include <sched.h>
+#include <stdlib.h>
 
 #include <algorithm>
 #include <vector>
@@ -185,6 +186,14 @@ TEST_F(ThreadListerTest, ResetMakesNewThreadsKnown) {
   ASSERT_TRUE(HasElement(threads_after_extra, extra_tid));
 }
 
+TEST(SanitizerCommon, SetEnvTest) {
+  const char kEnvName[] = "ENV_FOO";
+  SetEnv(kEnvName, "value");
+  EXPECT_STREQ("value", getenv(kEnvName));
+  unsetenv(kEnvName);
+  EXPECT_EQ(0, getenv(kEnvName));
+}
+
 }  // namespace __sanitizer
 
 #endif  // __linux__