[sanitizer] Add strlen to the common interceptors

Summary:
Adds strlen to the common interceptors, under a new common flag
intercept_strlen.  This provides better sharing of interception code among
sanitizers and cleans up the inconsistent type declarations of the
previously duplicated interceptors.

Removes the now-duplicate strlen interceptor from asan, msan, and tsan.
The entry check semantics are normalized now for msan and asan, whose
private strlen interceptors contained multiple layers of checks that
included impossible-to-reach code.  The new semantics are identical to the
old: bypass interception if in the middle of init or if both on Mac and not
initialized; else, call the init routine and proceed.

Patch by Derek Bruening!

Reviewers: samsonov, vitalybuka

Subscribers: llvm-commits, kcc, zhaoqin

Differential Revision: http://reviews.llvm.org/D18020

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@263177 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 4 insertions, 18 deletions

diff --git a/lib/asan/asan_flags.cc b/lib/asan/asan_flags.cc
index 363ee67e7..135341fc0 100644
--- a/lib/asan/asan_flags.cc
+++ b/lib/asan/asan_flags.cc
@@ -159,6 +159,10 @@ void InitializeFlags() {
         (ASAN_LOW_MEMORY) ? 1UL << 6 : 1UL << 8;
     f->quarantine_size_mb = kDefaultQuarantineSizeMb;
   }
+  if (!f->replace_str && common_flags()->intercept_strlen) {
+    Report("WARNING: strlen interceptor is enabled even though replace_str=0. "
+           "Use intercept_strlen=0 to disable it.");
+  }
 }
 
 }  // namespace __asan
diff --git a/lib/asan/asan_interceptors.cc b/lib/asan/asan_interceptors.cc
index faac15b32..4a10afcc1 100644
--- a/lib/asan/asan_interceptors.cc
+++ b/lib/asan/asan_interceptors.cc
@@ -580,23 +580,6 @@ INTERCEPTOR(char*, strdup, const char *s) {
 }
 #endif
 
-INTERCEPTOR(SIZE_T, strlen, const char *s) {
-  void *ctx;
-  ASAN_INTERCEPTOR_ENTER(ctx, strlen);
-  if (UNLIKELY(!asan_inited)) return internal_strlen(s);
-  // strlen is called from malloc_default_purgeable_zone()
-  // in __asan::ReplaceSystemAlloc() on Mac.
-  if (asan_init_is_running) {
-    return REAL(strlen)(s);
-  }
-  ENSURE_ASAN_INITED();
-  SIZE_T length = REAL(strlen)(s);
-  if (flags()->replace_str) {
-    ASAN_READ_RANGE(ctx, s, length + 1);
-  }
-  return length;
-}
-
 INTERCEPTOR(SIZE_T, wcslen, const wchar_t *s) {
   void *ctx;
   ASAN_INTERCEPTOR_ENTER(ctx, wcslen);
@@ -763,7 +746,6 @@ void InitializeAsanInterceptors() {
   ASAN_INTERCEPT_FUNC(strcat);  // NOLINT
   ASAN_INTERCEPT_FUNC(strchr);
   ASAN_INTERCEPT_FUNC(strcpy);  // NOLINT
-  ASAN_INTERCEPT_FUNC(strlen);
   ASAN_INTERCEPT_FUNC(wcslen);
   ASAN_INTERCEPT_FUNC(strncat);
   ASAN_INTERCEPT_FUNC(strncpy);