[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

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@373239 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 33 insertions, 7 deletions

diff --git a/lib/msan/msan_interceptors.cpp b/lib/msan/msan_interceptors.cpp
index ff760e43d..1d9d9f798 100644
--- a/lib/msan/msan_interceptors.cpp
+++ b/lib/msan/msan_interceptors.cpp
@@ -765,17 +765,24 @@ INTERCEPTOR(char *, fgets_unlocked, char *s, int size, void *stream) {
 #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 resource, void *new_rlimit,
   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;
diff --git a/test/msan/preinit_array.cpp b/test/msan/preinit_array.cpp
new file mode 100644
index 000000000..6f877bac0
--- /dev/null
+++ b/test/msan/preinit_array.cpp
@@ -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;
+}