[compiler-rt] r373239 - [msan] Intercept __getrlimit.

[Evgeniy Stepanov via llvm-commits]

Author: eugenis
Date: Mon Sep 30 10:49:48 2019
New Revision: 373239

URL: http://llvm.org/viewvc/llvm-project?rev=373239&view=rev
Log:
[msan] Intercept __getrlimit.

Summary:
This interceptor is useful on its own, but the main purpose of this
change is to intercept libpthread initialization on linux/glibc in
order to run __msan_init before any .preinit_array constructors.

We used to trigger on pthread_initialize_minimal -> getrlimit(), but
that call has changed to __getrlimit at some point.

Reviewers: vitalybuka, pcc

Subscribers: jfb, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D68168

Added:
    compiler-rt/trunk/test/msan/preinit_array.cpp
Modified:
    compiler-rt/trunk/lib/msan/msan_interceptors.cpp

Modified: compiler-rt/trunk/lib/msan/msan_interceptors.cpp
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_interceptors.cpp?rev=373239&r1=373238&r2=373239&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan_interceptors.cpp (original)
+++ compiler-rt/trunk/lib/msan/msan_interceptors.cpp Mon Sep 30 10:49:48 2019
@@ -765,17 +765,24 @@ INTERCEPTOR(char *, fgets_unlocked, char
 #define MSAN_MAYBE_INTERCEPT_FGETS_UNLOCKED
 #endif
 
+#define INTERCEPTOR_GETRLIMIT_BODY(func, resource, rlim)  \
+  if (msan_init_is_running)                               \
+    return REAL(getrlimit)(resource, rlim);               \
+  ENSURE_MSAN_INITED();                                   \
+  int res = REAL(func)(resource, rlim);                   \
+  if (!res)                                               \
+    __msan_unpoison(rlim, __sanitizer::struct_rlimit_sz); \
+  return res
+
 INTERCEPTOR(int, getrlimit, int resource, void *rlim) {
-  if (msan_init_is_running)
-    return REAL(getrlimit)(resource, rlim);
-  ENSURE_MSAN_INITED();
-  int res = REAL(getrlimit)(resource, rlim);
-  if (!res)
-    __msan_unpoison(rlim, __sanitizer::struct_rlimit_sz);
-  return res;
+  INTERCEPTOR_GETRLIMIT_BODY(getrlimit, resource, rlim);
 }
 
 #if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
+INTERCEPTOR(int, __getrlimit, int resource, void *rlim) {
+  INTERCEPTOR_GETRLIMIT_BODY(__getrlimit, resource, rlim);
+}
+
 INTERCEPTOR(int, getrlimit64, int resource, void *rlim) {
   if (msan_init_is_running) return REAL(getrlimit64)(resource, rlim);
   ENSURE_MSAN_INITED();
@@ -806,10 +813,12 @@ INTERCEPTOR(int, prlimit64, int pid, int
   return res;
 }
 
+#define MSAN_MAYBE_INTERCEPT___GETRLIMIT INTERCEPT_FUNCTION(__getrlimit)
 #define MSAN_MAYBE_INTERCEPT_GETRLIMIT64 INTERCEPT_FUNCTION(getrlimit64)
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT INTERCEPT_FUNCTION(prlimit)
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT64 INTERCEPT_FUNCTION(prlimit64)
 #else
+#define MSAN_MAYBE_INTERCEPT___GETRLIMIT
 #define MSAN_MAYBE_INTERCEPT_GETRLIMIT64
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT64
@@ -1678,6 +1687,7 @@ void InitializeInterceptors() {
   INTERCEPT_FUNCTION(socketpair);
   MSAN_MAYBE_INTERCEPT_FGETS_UNLOCKED;
   INTERCEPT_FUNCTION(getrlimit);
+  MSAN_MAYBE_INTERCEPT___GETRLIMIT;
   MSAN_MAYBE_INTERCEPT_GETRLIMIT64;
   MSAN_MAYBE_INTERCEPT_PRLIMIT;
   MSAN_MAYBE_INTERCEPT_PRLIMIT64;

Added: compiler-rt/trunk/test/msan/preinit_array.cpp
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/msan/preinit_array.cpp?rev=373239&view=auto
==============================================================================
--- compiler-rt/trunk/test/msan/preinit_array.cpp (added)
+++ compiler-rt/trunk/test/msan/preinit_array.cpp Mon Sep 30 10:49:48 2019
@@ -0,0 +1,16 @@
+// RUN: %clangxx_msan -O0 %s -o %t && %run %t
+
+#include <sanitizer/msan_interface.h>
+
+volatile int global;
+static void pre_ctor() {
+  volatile int local;
+  global = 42;
+  local = 42;
+}
+
+__attribute__((section(".preinit_array"), used)) void(*__local_pre_ctor)(void) = pre_ctor;
+
+int main(void) {
+  return 0;
+}