From c6721f580df11bb0bd00217a45430d163770a278 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Thu, 9 Nov 2017 02:22:07 +0000
Subject: [PATCH] ubsan: Allow programs to use setenv to configure
 ubsan_standalone.

Previously ubsan_standalone used the GetEnv function to read the
environment variables UBSAN_OPTIONS and UBSAN_SYMBOLIZER_PATH. The
problem with GetEnv is that it does not respect changes to the
environment variables made using the libc setenv function, which
prevents clients from setting environment variables to configure
ubsan before loading ubsan-instrumented libraries.

The reason why we have GetEnv is that some runtimes need to read
environment variables while they initialize using .preinit_array,
and getenv does not work while .preinit_array functions are being
called. However, it is unnecessary for ubsan_standalone to initialize
that early. So this change switches ubsan_standalone to using getenv
and removes the .preinit_array entry. The static version of the runtime
still ends up being initialized using a C++ constructor that exists
to support the shared runtime.

Differential Revision: https://reviews.llvm.org/D39827

llvm-svn: 317757
---
 compiler-rt/lib/ubsan/CMakeLists.txt               |  1 -
 compiler-rt/lib/ubsan/ubsan_flags.cc               |  6 ++--
 .../lib/ubsan/ubsan_init_standalone_preinit.cc     | 37 ----------------------
 3 files changed, 4 insertions(+), 40 deletions(-)
 delete mode 100644 compiler-rt/lib/ubsan/ubsan_init_standalone_preinit.cc

diff --git a/compiler-rt/lib/ubsan/CMakeLists.txt b/compiler-rt/lib/ubsan/CMakeLists.txt
index 911bd3e..ea4f6e8 100644
--- a/compiler-rt/lib/ubsan/CMakeLists.txt
+++ b/compiler-rt/lib/ubsan/CMakeLists.txt
@@ -151,7 +151,6 @@ else()
     add_compiler_rt_runtime(clang_rt.ubsan_standalone
       STATIC
       ARCHS ${UBSAN_SUPPORTED_ARCH}
-      SOURCES ubsan_init_standalone_preinit.cc
       OBJECT_LIBS RTSanitizerCommon
               RTSanitizerCommonLibc
               RTUbsan
diff --git a/compiler-rt/lib/ubsan/ubsan_flags.cc b/compiler-rt/lib/ubsan/ubsan_flags.cc
index 8e1f408..c4fb278 100644
--- a/compiler-rt/lib/ubsan/ubsan_flags.cc
+++ b/compiler-rt/lib/ubsan/ubsan_flags.cc
@@ -18,6 +18,8 @@
 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_flag_parser.h"
 
+#include <stdlib.h>
+
 namespace __ubsan {
 
 const char *MaybeCallUbsanDefaultOptions() {
@@ -45,7 +47,7 @@ void InitializeFlags() {
     CommonFlags cf;
     cf.CopyFrom(*common_flags());
     cf.print_summary = false;
-    cf.external_symbolizer_path = GetEnv("UBSAN_SYMBOLIZER_PATH");
+    cf.external_symbolizer_path = getenv("UBSAN_SYMBOLIZER_PATH");
     OverrideCommonFlags(cf);
   }
 
@@ -59,7 +61,7 @@ void InitializeFlags() {
   // Override from user-specified string.
   parser.ParseString(MaybeCallUbsanDefaultOptions());
   // Override from environment variable.
-  parser.ParseString(GetEnv("UBSAN_OPTIONS"));
+  parser.ParseString(getenv("UBSAN_OPTIONS"));
   InitializeCommonFlags();
   if (Verbosity()) ReportUnrecognizedFlags();
 
diff --git a/compiler-rt/lib/ubsan/ubsan_init_standalone_preinit.cc b/compiler-rt/lib/ubsan/ubsan_init_standalone_preinit.cc
deleted file mode 100644
index 9a8c688..0000000
--- a/compiler-rt/lib/ubsan/ubsan_init_standalone_preinit.cc
+++ /dev/null
@@ -1,37 +0,0 @@
-//===-- ubsan_init_standalone_preinit.cc
-//------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// Initialization of standalone UBSan runtime.
-//
-//===----------------------------------------------------------------------===//
-
-#include "ubsan_platform.h"
-#if !CAN_SANITIZE_UB
-#error "UBSan is not supported on this platform!"
-#endif
-
-#include "sanitizer_common/sanitizer_internal_defs.h"
-#include "ubsan_init.h"
-#include "ubsan_signals_standalone.h"
-
-#if SANITIZER_CAN_USE_PREINIT_ARRAY
-
-namespace __ubsan {
-
-static void PreInitAsStandalone() {
-  InitAsStandalone();
-  InitializeDeadlySignals();
-}
-
-} // namespace __ubsan
-
-__attribute__((section(".preinit_array"), used)) void (*__local_ubsan_preinit)(
-    void) = __ubsan::PreInitAsStandalone;
-#endif // SANITIZER_CAN_USE_PREINIT_ARRAY
-- 
2.7.4