[sanitizer_common] Fuchsia support for interceptors

Summary:
Actually Fuchsia non-support for interceptors.  Fuchsia doesn't use
interceptors in the common sense at all.  Almost all system library
functions don't need interception at all, because the system
libraries are just themselves compiled with sanitizers enabled and
have specific hook interfaces where needed to inform the sanitizer
runtime about thread lifetimes and the like.  For the few functions
that do get intercepted, they don't use a generic mechanism like
dlsym with RTLD_NEXT to find the underlying system library function.
Instead, they use specific extra symbol names published by the
system library (e.g. __unsanitized_memcpy).

Submitted on behalf of Roland McGrath.

Reviewers: vitalybuka, alekseyshl, kcc, filcab

Reviewed By: filcab

Subscribers: kubamracek, phosek, filcab, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D36028

llvm-svn: 309745

Author: vitalybuka

compiler-rt/lib/interception/interception.h

@@ -15,8 +15,8 @@
 #ifndef INTERCEPTION_H
 #define INTERCEPTION_H
 
-#if !defined(__linux__) && !defined(__FreeBSD__) && \
-  !defined(__APPLE__) && !defined(_WIN32)
+#if !defined(__linux__) && !defined(__FreeBSD__) && !defined(__APPLE__) && \
+    !defined(_WIN32) && !defined(__Fuchsia__)
 # error "Interception doesn't work on this operating system."
 #endif
 
@@ -139,7 +139,7 @@ const interpose_substitution substitution_##func_name[] \
 # define DECLARE_WRAPPER(ret_type, func, ...) \
      extern "C" ret_type func(__VA_ARGS__) \
      __attribute__((alias("__interceptor_" #func), visibility("default")));
-#else
+#elif !defined(__Fuchsia__)
 # define WRAP(x) __interceptor_ ## x
 # define WRAPPER_NAME(x) "__interceptor_" #x
 # define INTERCEPTOR_ATTRIBUTE __attribute__((visibility("default")))
@@ -148,7 +148,15 @@ const interpose_substitution substitution_##func_name[] \
     __attribute__((weak, alias("__interceptor_" #func), visibility("default")));
 #endif
 
-#if !defined(__APPLE__)
+#if defined(__Fuchsia__)
+// There is no general interception at all on Fuchsia.
+// Sanitizer runtimes just define functions directly to preempt them,
+// and have bespoke ways to access the underlying libc functions.
+# include <magenta/sanitizer.h>
+# define INTERCEPTOR_ATTRIBUTE __attribute__((visibility("default")))
+# define REAL(x) __unsanitized_##x
+# define DECLARE_REAL(ret_type, func, ...)
+#elif !defined(__APPLE__)
 # define PTR_TO_REAL(x) real_##x
 # define REAL(x) __interception::PTR_TO_REAL(x)
 # define FUNC_TYPE(x) x##_f
@@ -166,15 +174,19 @@ const interpose_substitution substitution_##func_name[] \
 # define ASSIGN_REAL(x, y)
 #endif  // __APPLE__
 
+#if !defined(__Fuchsia__)
 #define DECLARE_REAL_AND_INTERCEPTOR(ret_type, func, ...) \
   DECLARE_REAL(ret_type, func, __VA_ARGS__) \
   extern "C" ret_type WRAP(func)(__VA_ARGS__);
+#else
+#define DECLARE_REAL_AND_INTERCEPTOR(ret_type, func, ...)
+#endif
 
 // Generally, you don't need to use DEFINE_REAL by itself, as INTERCEPTOR
 // macros does its job. In exceptional cases you may need to call REAL(foo)
 // without defining INTERCEPTOR(..., foo, ...). For example, if you override
 // foo with an interceptor for other function.
-#if !defined(__APPLE__)
+#if !defined(__APPLE__) && !defined(__Fuchsia__)
 # define DEFINE_REAL(ret_type, func, ...) \
     typedef ret_type (*FUNC_TYPE(func))(__VA_ARGS__); \
     namespace __interception { \
@@ -184,7 +196,18 @@ const interpose_substitution substitution_##func_name[] \
 # define DEFINE_REAL(ret_type, func, ...)
 #endif
 
-#if !defined(__APPLE__)
+#if defined(__Fuchsia__)
+
+// We need to define the __interceptor_func name just to get
+// sanitizer_common/scripts/gen_dynamic_list.py to export func.
+// But we don't need to export __interceptor_func to get that.
+#define INTERCEPTOR(ret_type, func, ...)                                \
+  extern "C"[[ gnu::alias(#func), gnu::visibility("hidden") ]] ret_type \
+      __interceptor_##func(__VA_ARGS__);                                \
+  extern "C" INTERCEPTOR_ATTRIBUTE ret_type func(__VA_ARGS__)
+
+#elif !defined(__APPLE__)
+
 #define INTERCEPTOR(ret_type, func, ...) \
   DEFINE_REAL(ret_type, func, __VA_ARGS__) \
   DECLARE_WRAPPER(ret_type, func, __VA_ARGS__) \
@@ -251,7 +274,7 @@ typedef unsigned long uptr;  // NOLINT
 # define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_MAC(func)
 # define INTERCEPT_FUNCTION_VER(func, symver) \
     INTERCEPT_FUNCTION_VER_MAC(func, symver)
-#else  // defined(_WIN32)
+#elif defined(_WIN32)
 # include "interception_win.h"
 # define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_WIN(func)
 # define INTERCEPT_FUNCTION_VER(func, symver) \

compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h

@@ -28,7 +28,7 @@
 # define SI_WINDOWS 1
 #endif
 
-#if (SI_POSIX != 0) == (SI_WINDOWS != 0)
+#if (SI_POSIX != 0) == (SI_WINDOWS != 0) && !SANITIZER_FUCHSIA
 # error "Windows is not POSIX!"
 #endif
 
@@ -80,6 +80,12 @@
 # define SI_IOS 0
 #endif
 
+#if SANITIZER_FUCHSIA
+# define SI_NOT_FUCHSIA 0
+#else
+# define SI_NOT_FUCHSIA 1
+#endif
+
 #if SANITIZER_POSIX && !SANITIZER_MAC
 # define SI_POSIX_NOT_MAC 1
 #else
@@ -92,23 +98,23 @@
 # define SI_LINUX_NOT_FREEBSD 0
 #endif
 
-#define SANITIZER_INTERCEPT_STRLEN 1
-#define SANITIZER_INTERCEPT_STRNLEN SI_NOT_MAC
-#define SANITIZER_INTERCEPT_STRCMP 1
-#define SANITIZER_INTERCEPT_STRSTR 1
+#define SANITIZER_INTERCEPT_STRLEN SI_NOT_FUCHSIA
+#define SANITIZER_INTERCEPT_STRNLEN (SI_NOT_MAC && SI_NOT_FUCHSIA)
+#define SANITIZER_INTERCEPT_STRCMP SI_NOT_FUCHSIA
+#define SANITIZER_INTERCEPT_STRSTR SI_NOT_FUCHSIA
 #define SANITIZER_INTERCEPT_STRCASESTR SI_POSIX
-#define SANITIZER_INTERCEPT_STRTOK 1
-#define SANITIZER_INTERCEPT_STRCHR 1
-#define SANITIZER_INTERCEPT_STRCHRNUL SI_UNIX_NOT_MAC
-#define SANITIZER_INTERCEPT_STRRCHR 1
-#define SANITIZER_INTERCEPT_STRSPN 1
-#define SANITIZER_INTERCEPT_STRPBRK 1
+#define SANITIZER_INTERCEPT_STRTOK SI_NOT_FUCHSIA
+#define SANITIZER_INTERCEPT_STRCHR SI_NOT_FUCHSIA
+#define SANITIZER_INTERCEPT_STRCHRNUL SI_POSIX_NOT_MAC
+#define SANITIZER_INTERCEPT_STRRCHR SI_NOT_FUCHSIA
+#define SANITIZER_INTERCEPT_STRSPN SI_NOT_FUCHSIA
+#define SANITIZER_INTERCEPT_STRPBRK SI_NOT_FUCHSIA
 #define SANITIZER_INTERCEPT_TEXTDOMAIN SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_STRCASECMP SI_POSIX
 #define SANITIZER_INTERCEPT_MEMSET 1
 #define SANITIZER_INTERCEPT_MEMMOVE 1
 #define SANITIZER_INTERCEPT_MEMCPY 1
-#define SANITIZER_INTERCEPT_MEMCMP 1
+#define SANITIZER_INTERCEPT_MEMCMP SI_NOT_FUCHSIA
 #define SANITIZER_INTERCEPT_STRNDUP SI_POSIX
 #define SANITIZER_INTERCEPT___STRNDUP SI_LINUX_NOT_FREEBSD
 #if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && \
@@ -120,7 +126,7 @@
 // memmem on Darwin doesn't exist on 10.6
 // FIXME: enable memmem on Windows.
 #define SANITIZER_INTERCEPT_MEMMEM (SI_POSIX && !SI_MAC_DEPLOYMENT_BELOW_10_7)
-#define SANITIZER_INTERCEPT_MEMCHR 1
+#define SANITIZER_INTERCEPT_MEMCHR SI_NOT_FUCHSIA
 #define SANITIZER_INTERCEPT_MEMRCHR (SI_FREEBSD || SI_LINUX || SI_NETBSD)
 
 #define SANITIZER_INTERCEPT_READ SI_POSIX
@@ -157,7 +163,7 @@
 # define SANITIZER_INTERCEPT_ISOC99_PRINTF SI_LINUX_NOT_ANDROID
 #endif
 
-#define SANITIZER_INTERCEPT_FREXP 1
+#define SANITIZER_INTERCEPT_FREXP SI_NOT_FUCHSIA
 #define SANITIZER_INTERCEPT_FREXPF_FREXPL SI_POSIX
 
 #define SANITIZER_INTERCEPT_GETPWNAM_AND_FRIENDS SI_POSIX
@@ -372,10 +378,12 @@
   (SI_LINUX_NOT_ANDROID || SI_MAC || SI_FREEBSD || SI_NETBSD)
 
 #define SANITIZER_INTERCEPT_MALLOPT_AND_MALLINFO \
-  (!SI_FREEBSD && !SI_MAC && !SI_NETBSD)
+  (!SI_FREEBSD && !SI_MAC && !SI_NETBSD && SI_NOT_FUCHSIA)
 #define SANITIZER_INTERCEPT_MEMALIGN (!SI_FREEBSD && !SI_MAC && !SI_NETBSD)
-#define SANITIZER_INTERCEPT_PVALLOC (!SI_FREEBSD && !SI_MAC && !SI_NETBSD)
-#define SANITIZER_INTERCEPT_CFREE (!SI_FREEBSD && !SI_MAC && !SI_NETBSD)
+#define SANITIZER_INTERCEPT_PVALLOC \
+  (!SI_FREEBSD && !SI_MAC && !SI_NETBSD && SI_NOT_FUCHSIA)
+#define SANITIZER_INTERCEPT_CFREE \
+  (!SI_FREEBSD && !SI_MAC && !SI_NETBSD && SI_NOT_FUCHSIA)
 #define SANITIZER_INTERCEPT_ALIGNED_ALLOC (!SI_MAC)
 #define SANITIZER_INTERCEPT_MALLOC_USABLE_SIZE (!SI_MAC)
 #define SANITIZER_INTERCEPT_MCHECK_MPROBE SI_LINUX_NOT_ANDROID