[interception] Implement interception on AIX (#138608)

Implement AIX specific interception functions.

Issue: https://github.com/llvm/llvm-project/issues/138916

compiler-rt/lib/interception/CMakeLists.txt

@@ -1,6 +1,7 @@
 # Build for the runtime interception helper library.
 
 set(INTERCEPTION_SOURCES
+  interception_aix.cpp
   interception_linux.cpp
   interception_mac.cpp
   interception_win.cpp
@@ -9,6 +10,7 @@ set(INTERCEPTION_SOURCES
 
 set(INTERCEPTION_HEADERS
   interception.h
+  interception_aix.h
   interception_linux.h
   interception_mac.h
   interception_win.h

compiler-rt/lib/interception/interception.h

@@ -19,7 +19,7 @@
 
 #if !SANITIZER_LINUX && !SANITIZER_FREEBSD && !SANITIZER_APPLE &&    \
     !SANITIZER_NETBSD && !SANITIZER_WINDOWS && !SANITIZER_FUCHSIA && \
-    !SANITIZER_SOLARIS && !SANITIZER_HAIKU
+    !SANITIZER_SOLARIS && !SANITIZER_HAIKU && !SANITIZER_AIX
 #  error "Interception doesn't work on this operating system."
 #endif
 
@@ -168,6 +168,16 @@ const interpose_substitution substitution_##func_name[]             \
     extern "C" ret_type func(__VA_ARGS__);
 # define DECLARE_WRAPPER_WINAPI(ret_type, func, ...)  \
     extern "C" __declspec(dllimport) ret_type __stdcall func(__VA_ARGS__);
+#elif SANITIZER_AIX
+#  define WRAP(x) __interceptor_##x
+#  define TRAMPOLINE(x) WRAP(x)
+// # define WRAPPER_NAME(x) "__interceptor_" #x
+#  define INTERCEPTOR_ATTRIBUTE __attribute__((visibility("default")))
+// AIX's linker will not select the weak symbol, so don't use weak for the
+// interceptors.
+#  define DECLARE_WRAPPER(ret_type, func, ...) \
+    extern "C" ret_type func(__VA_ARGS__)      \
+        __attribute__((alias("__interceptor_" #func), visibility("default")));
 #elif !SANITIZER_FUCHSIA  // LINUX, FREEBSD, NETBSD, SOLARIS
 # define INTERCEPTOR_ATTRIBUTE __attribute__((visibility("default")))
 # if ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT
@@ -367,12 +377,17 @@ inline void DoesNotSupportStaticLinking() {}
 
 #define INCLUDED_FROM_INTERCEPTION_LIB
 
-#if SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD || \
+#if SANITIZER_AIX
+#  include "interception_aix.h"
+#  define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_AIX(func)
+#  define INTERCEPT_FUNCTION_VER(func, symver) INTERCEPT_FUNCTION_AIX(func)
+
+#elif SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD || \
     SANITIZER_SOLARIS || SANITIZER_HAIKU
 
-# include "interception_linux.h"
-# define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_LINUX_OR_FREEBSD(func)
-# define INTERCEPT_FUNCTION_VER(func, symver) \
+#  include "interception_linux.h"
+#  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 SANITIZER_APPLE
 # include "interception_mac.h"

compiler-rt/lib/interception/interception_aix.cpp

@@ -0,0 +1,45 @@
+//===-- interception_aix.cpp ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// AIX-specific interception methods.
+//===----------------------------------------------------------------------===//
+
+#include "interception.h"
+#include "sanitizer_common/sanitizer_common.h"
+
+#if SANITIZER_AIX
+
+#  include <dlfcn.h>  // for dlsym()
+
+namespace __interception {
+
+static void *GetFuncAddr(const char *name, uptr wrapper_addr) {
+  // AIX dlsym can only defect the functions that are exported, so
+  // on AIX, we can not intercept some basic functions like memcpy.
+  // FIXME: if we are going to ship dynamic asan library, we may need to search
+  // all the loaded modules with RTLD_DEFAULT if RTLD_NEXT failed.
+  void *addr = dlsym(RTLD_NEXT, name);
+
+  // In case `name' is not loaded, dlsym ends up finding the actual wrapper.
+  // We don't want to intercept the wrapper and have it point to itself.
+  if ((uptr)addr == wrapper_addr)
+    addr = nullptr;
+  return addr;
+}
+
+bool InterceptFunction(const char *name, uptr *ptr_to_real, uptr func,
+                       uptr wrapper) {
+  void *addr = GetFuncAddr(name, wrapper);
+  *ptr_to_real = (uptr)addr;
+  return addr && (func == wrapper);
+}
+
+}  // namespace __interception
+#endif  // SANITIZER_AIX

compiler-rt/lib/interception/interception_aix.h

@@ -0,0 +1,36 @@
+//===-- interception_aix.h --------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// AIX-specific interception methods.
+//===----------------------------------------------------------------------===//
+
+#if SANITIZER_AIX
+
+#  if !defined(INCLUDED_FROM_INTERCEPTION_LIB)
+#    error \
+        "interception_aix.h should be included from interception library only"
+#  endif
+
+#  ifndef INTERCEPTION_AIX_H
+#    define INTERCEPTION_AIX_H
+
+namespace __interception {
+bool InterceptFunction(const char *name, uptr *ptr_to_real, uptr func,
+                       uptr wrapper);
+}  // namespace __interception
+
+#    define INTERCEPT_FUNCTION_AIX(func)                \
+      ::__interception::InterceptFunction(              \
+          #func, (::__interception::uptr *)&REAL(func), \
+          (::__interception::uptr) & (func),            \
+          (::__interception::uptr) & WRAP(func))
+
+#  endif  // INTERCEPTION_AIX_H
+#endif    // SANITIZER_AIX