[MSan] Use COMMON_INTERCEPTOR_ENTER in libdl interceptors.

[• koriakin]

Summary

This fixes fails in test/msan/dlerror.cc - when real dlerror calls strcmp,
our strcmp interceptor now skips poison checking, since it's called in
interceptor context. Strictly speaking, only the dlerror change is
necessary to fix the fail, but let's also change the other two just in case.

This fixes the bug XFAILed in D19205 (obsoleting it) and D17503.

[eugenis]

Looks great, but please keep COMMON_INTERCEPTOR_* macros together. Move dl* interceptors code instead.

[• koriakin]

This version moves the interceptors instead of moving the macro and struct.

[eugenis]

LGTM

compiler-rt/trunk/lib/msan/msan_interceptors.cc

if (res != (void*)-1)
     __msan_unpoison(res, RoundUpTo(length, GetPageSize()));
   return res;
 }
 #define MSAN_MAYBE_INTERCEPT_MMAP64 INTERCEPT_FUNCTION(mmap64)
 #else
 #define MSAN_MAYBE_INTERCEPT_MMAP64
 #endif
 
-struct dlinfo {
-  char *dli_fname;
-  void *dli_fbase;
-  char *dli_sname;
-  void *dli_saddr;
-};
-
-INTERCEPTOR(int, dladdr, void *addr, dlinfo *info) {
-  ENSURE_MSAN_INITED();
-  int res = REAL(dladdr)(addr, info);
-  if (res != 0) {
-    __msan_unpoison(info, sizeof(*info));
-    if (info->dli_fname)
-      __msan_unpoison(info->dli_fname, REAL(strlen)(info->dli_fname) + 1);
-    if (info->dli_sname)
-      __msan_unpoison(info->dli_sname, REAL(strlen)(info->dli_sname) + 1);
-  }
-  return res;
-}
-
-INTERCEPTOR(char *, dlerror, int fake) {
-  ENSURE_MSAN_INITED();
-  char *res = REAL(dlerror)(fake);
-  if (res) __msan_unpoison(res, REAL(strlen)(res) + 1);
-  return res;
-}
-
-typedef int (*dl_iterate_phdr_cb)(__sanitizer_dl_phdr_info *info, SIZE_T size,
-                                  void *data);
-struct dl_iterate_phdr_data {
-  dl_iterate_phdr_cb callback;
-  void *data;
-};
-
-static int msan_dl_iterate_phdr_cb(__sanitizer_dl_phdr_info *info, SIZE_T size,
-                                   void *data) {
-  if (info) {
-    __msan_unpoison(info, size);
-    if (info->dlpi_phdr && info->dlpi_phnum)
-      __msan_unpoison(info->dlpi_phdr, struct_ElfW_Phdr_sz * info->dlpi_phnum);
-    if (info->dlpi_name)
-      __msan_unpoison(info->dlpi_name, REAL(strlen)(info->dlpi_name) + 1);
-  }
-  dl_iterate_phdr_data *cbdata = (dl_iterate_phdr_data *)data;
-  UnpoisonParam(3);
-  return cbdata->callback(info, size, cbdata->data);
-}
-
-INTERCEPTOR(int, dl_iterate_phdr, dl_iterate_phdr_cb callback, void *data) {
-  ENSURE_MSAN_INITED();
-  dl_iterate_phdr_data cbdata;
-  cbdata.callback = callback;
-  cbdata.data = data;
-  int res = REAL(dl_iterate_phdr)(msan_dl_iterate_phdr_cb, (void *)&cbdata);
-  return res;
-}
-
 INTERCEPTOR(int, getrusage, int who, void *usage) {
   ENSURE_MSAN_INITED();
   int res = REAL(getrusage)(who, usage);
   if (res == 0) {
     __msan_unpoison(usage, __sanitizer::struct_rusage_sz);
   }
   return res;
 }
#define COMMON_SYSCALL_PRE_WRITE_RANGE(p, s) \
   do {                                       \
   } while (false)
 #define COMMON_SYSCALL_POST_READ_RANGE(p, s) \
   do {                                       \
   } while (false)
 #define COMMON_SYSCALL_POST_WRITE_RANGE(p, s) __msan_unpoison(p, s)
 #include "sanitizer_common/sanitizer_common_syscalls.inc"
 
+struct dlinfo {
+  char *dli_fname;
+  void *dli_fbase;
+  char *dli_sname;
+  void *dli_saddr;
+};
+
+INTERCEPTOR(int, dladdr, void *addr, dlinfo *info) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, dladdr, addr, info);
+  int res = REAL(dladdr)(addr, info);
+  if (res != 0) {
+    __msan_unpoison(info, sizeof(*info));
+    if (info->dli_fname)
+      __msan_unpoison(info->dli_fname, REAL(strlen)(info->dli_fname) + 1);
+    if (info->dli_sname)
+      __msan_unpoison(info->dli_sname, REAL(strlen)(info->dli_sname) + 1);
+  }
+  return res;
+}
+
+INTERCEPTOR(char *, dlerror, int fake) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, dlerror, fake);
+  char *res = REAL(dlerror)(fake);
+  if (res) __msan_unpoison(res, REAL(strlen)(res) + 1);
+  return res;
+}
+
+typedef int (*dl_iterate_phdr_cb)(__sanitizer_dl_phdr_info *info, SIZE_T size,
+                                  void *data);
+struct dl_iterate_phdr_data {
+  dl_iterate_phdr_cb callback;
+  void *data;
+};
+
+static int msan_dl_iterate_phdr_cb(__sanitizer_dl_phdr_info *info, SIZE_T size,
+                                   void *data) {
+  if (info) {
+    __msan_unpoison(info, size);
+    if (info->dlpi_phdr && info->dlpi_phnum)
+      __msan_unpoison(info->dlpi_phdr, struct_ElfW_Phdr_sz * info->dlpi_phnum);
+    if (info->dlpi_name)
+      __msan_unpoison(info->dlpi_name, REAL(strlen)(info->dlpi_name) + 1);
+  }
+  dl_iterate_phdr_data *cbdata = (dl_iterate_phdr_data *)data;
+  UnpoisonParam(3);
+  return cbdata->callback(info, size, cbdata->data);
+}
+
+INTERCEPTOR(int, dl_iterate_phdr, dl_iterate_phdr_cb callback, void *data) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, dl_iterate_phdr, callback, data);
+  dl_iterate_phdr_data cbdata;
+  cbdata.callback = callback;
+  cbdata.data = data;
+  int res = REAL(dl_iterate_phdr)(msan_dl_iterate_phdr_cb, (void *)&cbdata);
+  return res;
+}
+
 // These interface functions reside here so that they can use
 // REAL(memset), etc.
 void __msan_unpoison(const void *a, uptr size) {
   if (!MEM_IS_APP(a)) return;
   SetShadow(a, size, 0);
 }
 
 void __msan_poison(const void *a, uptr size) {

compiler-rt/trunk/test/msan/dlerror.cc

 // RUN: %clangxx_msan -O0 %s -o %t && %run %t
-//
-// AArch64, MIPS64 shows fails with uninitialized bytes in __interceptor_strcmp from
-// dlfcn/dlerror.c:107 (glibc).
-// XFAIL: aarch64
-// XFAIL: mips64
 
 #include <assert.h>
 #include <dlfcn.h>
 #include <stdio.h>
 #include <string.h>
 
 int main(void) {
   void *p = dlopen("/bad/file/name", RTLD_NOW);
   assert(!p);
   char *s = dlerror();
   printf("%s, %zu\n", s, strlen(s));
   return 0;
 }