[sanitizer_common] Fuchsia support for interceptors

[mcgrathr]

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).

[vitalybuka]

Could you please split WINDOWS->POSIX and Fuchsia changes into different patches so that we land refactoring first.

lib/sanitizer_common/sanitizer_platform_interceptors.h

40 ↗

(On Diff #108728)

Could you please add some sanity check like:
#if SI_POSIX == SI_WINDOWS
#error

78 ↗

(On Diff #108728)

SHould this be

$if SANITIZER_POSIX && !SANITIZER_MAC

[mcgrathr]

lib/sanitizer_common/sanitizer_platform_interceptors.h

40 ↗

(On Diff #108728)

Done in D36038

78 ↗

(On Diff #108728)

Done in D36038

[mcgrathr]

Rebased after D36038 split out

[filcab]

LGTM. You might want to remove this from the commit message, though:

Fuchsia is neither Windows nor POSIX. The SI_NOT_WINDOWS macro in
sanitizer_platform_interceptors.h was already effectively the same
as SI_POSIX, so just use SI_POSIX instead.

Thank you,

Filipe

[mcgrathr]

Rebased and ready to land.
Please land it for me!

Thanks,
Roland

compiler-rt/trunk/lib/interception/interception.h

 // This file is a part of AddressSanitizer, an address sanity checker.
 //
 // Machinery for providing replacements/wrappers for system functions.
 //===----------------------------------------------------------------------===//
 
 #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
 
 #include "sanitizer_common/sanitizer_internal_defs.h"
 
 // These typedefs should be used only in the interceptor definitions to replace
 // the standard system types (e.g. SSIZE_T instead of ssize_t)
 typedef __sanitizer::uptr    SIZE_T;

 # define WRAPPER_NAME(x) "__interceptor_" #x
 # define INTERCEPTOR_ATTRIBUTE __attribute__((visibility("default")))
 // FreeBSD's dynamic linker (incompliantly) gives non-weak symbols higher
 // priority than weak ones so weak aliases won't work for indirect calls
 // in position-independent (-fPIC / -fPIE) mode.
 # 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")))
 # define DECLARE_WRAPPER(ret_type, func, ...) \
     extern "C" ret_type func(__VA_ARGS__) \
     __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
 
 # define DECLARE_REAL(ret_type, func, ...) \
     typedef ret_type (*FUNC_TYPE(func))(__VA_ARGS__); \
     namespace __interception { \
       extern FUNC_TYPE(func) PTR_TO_REAL(func); \
     }
 # define ASSIGN_REAL(dst, src) REAL(dst) = REAL(src)
 #else  // __APPLE__
 # define REAL(x) x
 # define DECLARE_REAL(ret_type, func, ...) \
     extern "C" ret_type func(__VA_ARGS__);
 # 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 { \
       FUNC_TYPE(func) PTR_TO_REAL(func); \
     }
 #else
 # 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__) \
   extern "C" \
   INTERCEPTOR_ATTRIBUTE \
   ret_type WRAP(func)(__VA_ARGS__)
 
 // We don't need INTERCEPTOR_WITH_SUFFIX on non-Darwin for now.

 # define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_LINUX_OR_FREEBSD(func)
 # define INTERCEPT_FUNCTION_VER(func, symver) \
     INTERCEPT_FUNCTION_VER_LINUX_OR_FREEBSD(func, symver)
 #elif defined(__APPLE__)
 # include "interception_mac.h"
 # 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) \
     INTERCEPT_FUNCTION_VER_WIN(func, symver)
 #endif
 
 #undef INCLUDED_FROM_INTERCEPTION_LIB
 
 #endif  // INTERCEPTION_H

compiler-rt/trunk/lib/sanitizer_common/sanitizer_platform_interceptors.h

 #endif
 
 #if !SANITIZER_WINDOWS
 # define SI_WINDOWS 0
 #else
 # 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
 
 #if SI_POSIX
 # include "sanitizer_platform_limits_posix.h"
 #endif
 
 #if SANITIZER_LINUX && !SANITIZER_ANDROID

 #endif
 
 #if SANITIZER_IOS
 # define SI_IOS 1
 #else
 # 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
 # define SI_POSIX_NOT_MAC 0
 #endif
 
 #if SANITIZER_LINUX && !SANITIZER_FREEBSD
 # define SI_LINUX_NOT_FREEBSD 1
 # else
 # 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__) && \
     __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 1070
 # define SI_MAC_DEPLOYMENT_BELOW_10_7 1
 #else
 # define SI_MAC_DEPLOYMENT_BELOW_10_7 0
 #endif
 // 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
 #define SANITIZER_INTERCEPT_PREAD SI_POSIX
 #define SANITIZER_INTERCEPT_WRITE SI_POSIX
 #define SANITIZER_INTERCEPT_PWRITE SI_POSIX
 
 #define SANITIZER_INTERCEPT_FREAD SI_POSIX

 #define SANITIZER_INTERCEPT_ISOC99_SCANF SI_LINUX_NOT_ANDROID
 
 #ifndef SANITIZER_INTERCEPT_PRINTF
 # define SANITIZER_INTERCEPT_PRINTF SI_POSIX
 # define SANITIZER_INTERCEPT_PRINTF_L (SI_FREEBSD || SI_NETBSD)
 # 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
 #define SANITIZER_INTERCEPT_GETPWNAM_R_AND_FRIENDS \
   (SI_FREEBSD || SI_NETBSD || SI_MAC || SI_LINUX_NOT_ANDROID)
 #define SANITIZER_INTERCEPT_GETPWENT \
   (SI_FREEBSD || SI_NETBSD || SI_MAC || SI_LINUX_NOT_ANDROID)
 #define SANITIZER_INTERCEPT_FGETPWENT SI_LINUX_NOT_ANDROID

 
 #define SANITIZER_INTERCEPT_UTMP (SI_POSIX && !SI_MAC && !SI_FREEBSD)
 #define SANITIZER_INTERCEPT_UTMPX (SI_LINUX_NOT_ANDROID || SI_MAC || SI_FREEBSD)
 
 #define SANITIZER_INTERCEPT_GETLOADAVG \
   (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
 #define SANITIZER_INTERCEPT_WCSCAT SI_POSIX
 
 #endif  // #ifndef SANITIZER_PLATFORM_INTERCEPTORS_H