[msan] Extract signal_impl and sigaction_impl

[vitalybuka]

Summary

Preparation for using interceptor from sanitizer_common.

[vitalybuka]

less moving

[vitalybuka]

undo some changes

[vitalybuka]

Undo more changes

[eugenis]

compiler-rt/lib/msan/msan_interceptors.cc

1004

why forward declarations? Just move the interceptors below the _impl definitions.

[eugenis]

Ah ok I see your other change.

[vitalybuka]

update

compiler-rt/lib/msan/msan_interceptors.cc

static void SignalAction(int signo, void *si, void *uc) {
   __msan_unpoison(uc, __sanitizer::ucontext_t_sz);
 
   typedef void (*sigaction_cb)(int, void *, void *);
   sigaction_cb cb =
       (sigaction_cb)atomic_load(&sigactions[signo], memory_order_relaxed);
   cb(signo, si, uc);
 }
 
-static void read_sigaction(const __sanitizer_sigaction *act) {
-  CHECK_UNPOISONED(&act->sa_flags, sizeof(act->sa_flags));
-  if (act->sa_flags & __sanitizer::sa_siginfo)
-    CHECK_UNPOISONED(&act->sigaction, sizeof(act->sigaction));
-  else
-    CHECK_UNPOISONED(&act->handler, sizeof(act->handler));
-  CHECK_UNPOISONED(&act->sa_mask, sizeof(act->sa_mask));
-}
-
-INTERCEPTOR(int, sigaction, int signo, const __sanitizer_sigaction *act,
-            __sanitizer_sigaction *oldact) {
-  ENSURE_MSAN_INITED();
-  if (act) read_sigaction(act);
-  int res;
-  if (flags()->wrap_signals) {
-    SpinMutexLock lock(&sigactions_mu);
-    CHECK_LT(signo, kMaxSignals);
-    uptr old_cb = atomic_load(&sigactions[signo], memory_order_relaxed);
-    __sanitizer_sigaction new_act;
-    __sanitizer_sigaction *pnew_act = act ? &new_act : nullptr;
-    if (act) {
-      REAL(memcpy)(pnew_act, act, sizeof(__sanitizer_sigaction));
-      uptr cb = (uptr)pnew_act->sigaction;
-      uptr new_cb = (pnew_act->sa_flags & __sanitizer::sa_siginfo)
-                        ? (uptr)SignalAction
-                        : (uptr)SignalHandler;
-      if (cb != __sanitizer::sig_ign && cb != __sanitizer::sig_dfl) {
-        atomic_store(&sigactions[signo], cb, memory_order_relaxed);
-        pnew_act->sigaction = (void (*)(int, void *, void *))new_cb;
-      }
-    }
-    res = REAL(sigaction)(signo, pnew_act, oldact);
-    if (res == 0 && oldact) {
-      uptr cb = (uptr)oldact->sigaction;
-      if (cb != __sanitizer::sig_ign && cb != __sanitizer::sig_dfl) {
-        oldact->sigaction = (void (*)(int, void *, void *))old_cb;
-      }
-    }
-  } else {
-    res = REAL(sigaction)(signo, act, oldact);
-  }
+static void *signal_impl(int signum, void *handler);
+static int sigaction_impl(int signum, const __sanitizer_sigaction *act,
+                          __sanitizer_sigaction *oldact);
 
-  if (res == 0 && oldact) {
-    __msan_unpoison(oldact, sizeof(__sanitizer_sigaction));
-  }
-  return res;
+INTERCEPTOR(int, signal, int signum, void *handler) {
+  handler = signal_impl(signum, handler);
+  return REAL(signal)(signum, handler);
 }
 
-INTERCEPTOR(int, signal, int signo, uptr cb) {
-  ENSURE_MSAN_INITED();
-  if (flags()->wrap_signals) {
-    CHECK_LT(signo, kMaxSignals);
-    SpinMutexLock lock(&sigactions_mu);
-    if (cb != __sanitizer::sig_ign && cb != __sanitizer::sig_dfl) {
-      atomic_store(&sigactions[signo], cb, memory_order_relaxed);
-      cb = (uptr) SignalHandler;
-    }
-    return REAL(signal)(signo, cb);
-  } else {
-    return REAL(signal)(signo, cb);
-  }
+INTERCEPTOR(int, sigaction, int signum, const __sanitizer_sigaction *act,
+            __sanitizer_sigaction *oldact) {
+  return sigaction_impl(signum, act, oldact);
 }
 
 extern "C" int pthread_attr_init(void *attr);
 extern "C" int pthread_attr_destroy(void *attr);
 
 static void *MsanThreadStartFunc(void *arg) {
   MsanThread *t = (MsanThread *)arg;
   SetCurrentThread(t);
do {                                                      \
     GET_STORE_STACK_TRACE;                                  \
     CopyShadowAndOrigin(to, from, size, &stack);            \
     __msan_unpoison(to + size, 1);                          \
   } while (false)
 
 #include "sanitizer_common/sanitizer_platform_interceptors.h"
 #include "sanitizer_common/sanitizer_common_interceptors.inc"
 
+static void read_sigaction(const __sanitizer_sigaction *act) {
+  CHECK_UNPOISONED(&act->sa_flags, sizeof(act->sa_flags));
+  if (act->sa_flags & __sanitizer::sa_siginfo)
+    CHECK_UNPOISONED(&act->sigaction, sizeof(act->sigaction));
+  else
+    CHECK_UNPOISONED(&act->handler, sizeof(act->handler));
+  CHECK_UNPOISONED(&act->sa_mask, sizeof(act->sa_mask));
+}
+
+static void *signal_impl(int signo, void *handler) {
+  ENSURE_MSAN_INITED();
+  if (flags()->wrap_signals) {
+    CHECK_LT(signo, kMaxSignals);
+    SpinMutexLock lock(&sigactions_mu);
+    uptr cb = (uptr)handler;
+    if (cb != __sanitizer::sig_ign && cb != __sanitizer::sig_dfl) {
+      atomic_store(&sigactions[signo], cb, memory_order_relaxed);
+      return (void *)&SignalHandler;
+    }
+  }
+  return handler;
+}
+
+static int sigaction_impl(int signo, const __sanitizer_sigaction *act,
+                          __sanitizer_sigaction *oldact) {
+  ENSURE_MSAN_INITED();
+  if (act) read_sigaction(act);
+  int res;
+  if (flags()->wrap_signals) {
+    SpinMutexLock lock(&sigactions_mu);
+    CHECK_LT(signo, kMaxSignals);
+    uptr old_cb = atomic_load(&sigactions[signo], memory_order_relaxed);
+    __sanitizer_sigaction new_act;
+    __sanitizer_sigaction *pnew_act = act ? &new_act : nullptr;
+    if (act) {
+      REAL(memcpy)(pnew_act, act, sizeof(__sanitizer_sigaction));
+      uptr cb = (uptr)pnew_act->sigaction;
+      uptr new_cb = (pnew_act->sa_flags & __sanitizer::sa_siginfo)
+                        ? (uptr)SignalAction
+                        : (uptr)SignalHandler;
+      if (cb != __sanitizer::sig_ign && cb != __sanitizer::sig_dfl) {
+        atomic_store(&sigactions[signo], cb, memory_order_relaxed);
+        pnew_act->sigaction = (void (*)(int, void *, void *))new_cb;
+      }
+    }
+    res = REAL(sigaction)(signo, pnew_act, oldact);
+    if (res == 0 && oldact) {
+      uptr cb = (uptr)oldact->sigaction;
+      if (cb != __sanitizer::sig_ign && cb != __sanitizer::sig_dfl) {
+        oldact->sigaction = (void (*)(int, void *, void *))old_cb;
+      }
+    }
+  } else {
+    res = REAL(sigaction)(signo, act, oldact);
+  }
+
+  if (res == 0 && oldact) {
+    __msan_unpoison(oldact, sizeof(__sanitizer_sigaction));
+  }
+  return res;
+}
+
 #define COMMON_SYSCALL_PRE_READ_RANGE(p, s) CHECK_UNPOISONED(p, s)
 #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)