debug: seperate platform specifics into units

Makefile.am

@@ -327,6 +327,7 @@ UTIL_FILES   =			\
 if PLATFORM_LINUX
 UTIL_FILES += 			\
     backtrace_execinfo.cpp	\
+    debug_posix.cpp		\
     io_posix.cpp		\
     io_posix.hpp		\
     library_posix.hpp		\
@@ -340,6 +341,7 @@ endif
 if PLATFORM_WIN32
 UTIL_FILES += 			\
     backtrace_null.cpp		\
+    debug_win32.cpp		\
     io_win32.cpp		\
     library_win32.hpp		\
     library_win32.cpp		\

debug.cpp

@@ -11,7 +11,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
- * Copyright 2010 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2010-2016 Danny Robson <danny@nerdcruft.net>
  */
 
 #include "backtrace.hpp"
@@ -36,27 +36,6 @@ detail::panic (const char *msg)
 
 
 ////////////////////////////////////////////////////////////////////////////////
-#if defined(PLATFORM_WIN32)
-#include <windows.h>
-void
-breakpoint (void)
-{
-    DebugBreak ();
-}
-#else
-void
-breakpoint (void)
-{
-#if defined (__x86_64) || defined (__i386)
-    __asm__ ("int $3;");
-#else
-    raise (SIGINT);
-#endif
-}
-#endif
-
-
-//-----------------------------------------------------------------------------
 void
 detail::not_implemented (const char *msg)
 {
@@ -96,102 +75,13 @@ warn (const char *msg)
 }
 
 
-////////////////////////////////////////////////////////////////////////////////
-#if defined(PLATFORM_LINUX)
-#include <fenv.h>
-void
-enable_fpe (void)
-{
-    feenableexcept (FE_DIVBYZERO | FE_INVALID);
-}
-
-
-//-----------------------------------------------------------------------------
-void
-disable_fpe (void)
-{
-    feenableexcept (0);
-}
-#else
-// contropfp is not defined supposedly due to a regression in GCC include behaviours.
-
-
-//-----------------------------------------------------------------------------
-void
-enable_fpe (void)
-{
-    LOG_WARN ("Non-Linux exception code is broken under current GCC.");
-//    _clearfp();
-//    unsigned int ignored;
-//    _controlfp_s (&ignored, _MCW_EM, _MCW_EM);
-}
-
-
-//-----------------------------------------------------------------------------
-void
-disable_fpe (void)
-{
-    LOG_WARN ("Non-Linux exception code is broken under current GCC.");
-//    _clearfp();
-//    unsigned int ignored;
-//    _controlfp_s (&ignored, 0, _MCW_EM);
-}
-#endif
-
-
-////////////////////////////////////////////////////////////////////////////////
-#if defined(PLATFORM_WIN32)
-#include <io.h>
-#include <fcntl.h>
-
-void
-force_console (void)
-{
-    if (!AttachConsole (ATTACH_PARENT_PROCESS))
-        return;
-
-    auto out_handle = GetStdHandle (STD_OUTPUT_HANDLE);
-    auto err_handle = GetStdHandle (STD_ERROR_HANDLE);
-    auto in_handle  = GetStdHandle (STD_INPUT_HANDLE);
-
-    auto out_fd = _open_osfhandle (reinterpret_cast<intptr_t> (out_handle), _O_TEXT);
-    auto err_fd = _open_osfhandle (reinterpret_cast<intptr_t> (err_handle), _O_TEXT);
-    auto in_fd  = _open_osfhandle (reinterpret_cast<intptr_t> (in_handle),  _O_TEXT);
-
-    auto out_file = _fdopen (out_fd, "w");
-    auto err_file = _fdopen (err_fd, "w");
-    auto in_file  = _fdopen (in_fd,  "r");
-
-    /// FILE objects are not reassignable, but Windows doesn't leave us much
-    /// choice here.
-    *stdout = *out_file;
-    *stderr = *err_file;
-    *stdin  = *in_file;
-
-    setvbuf (stdout, NULL, _IONBF, 0);
-    setvbuf (stderr, NULL, _IONBF, 0);
-    setvbuf (stdin,  NULL, _IONBF, 0);
-
-    ios::sync_with_stdio ();
-
-    // Windows doesn't give an immediate newline when an application is run
-    // from a console, so we provide one here for sanity.
-    std::cout << "\n";
-    std::cerr << "Console installed\n";
-}
-#endif
-
-
 ////////////////////////////////////////////////////////////////////////////////
 void
 util::debug::init (void)
 {
-#if defined(PLATFORM_WIN32)
     force_console ();
+    prepare_debugger ();
 
-    if (nullptr == LoadLibrary("exchndl.dll")) {
+    if (getenv ("DEBUG_WAIT"))
-        std::cerr << GetLastError () << "\n";
+        await_debugger ();
-        LOG_WARNING("Emergency debugger not loaded");
-    }
-#endif
 }

debug.hpp

@@ -301,6 +301,10 @@ void warn (const char *);
 ///////////////////////////////////////////////////////////////////////////////
 void breakpoint (void);
 
+void await_debugger (void);
+void prepare_debugger (void);
+
+void force_console (void);
 
 ///////////////////////////////////////////////////////////////////////////////
 void enable_fpe (void);

debug_posix.cpp

@@ -0,0 +1,63 @@
+#include "./debug.hpp"
+
+#include "./log.hpp"
+
+#include <unistd.h>
+#include <sys/ptrace.h>
+#include <signal.h>
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+breakpoint (void)
+{
+#if defined (__x86_64) || defined (__i386)
+    __asm__ ("int $3;");
+#else
+    raise (SIGINT);
+#endif
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+prepare_debugger (void)
+{
+    ;
+}
+
+
+//-----------------------------------------------------------------------------
+void
+await_debugger (void)
+{
+    if (ptrace (PTRACE_TRACEME))
+        LOG_CRITICAL ("unable to wait for debugger");
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+#include <fenv.h>
+void
+enable_fpe (void)
+{
+    feenableexcept (FE_DIVBYZERO | FE_INVALID);
+}
+
+
+//-----------------------------------------------------------------------------
+void
+disable_fpe (void)
+{
+    feenableexcept (0);
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+force_console (void)
+{
+    if (!isatty (fileno (stdout))) {
+        LOG_ERROR ("expected debugging under a console");
+    }
+}

debug_win32.cpp

@@ -0,0 +1,113 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2016 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "./debug.hpp"
+
+#include "./except.hpp"
+
+#include <windows.h>
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+breakpoint (void)
+{
+    DebugBreak ();
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+await_debugger (void)
+{
+    // HACK: This is terribly inefficient, but it's not a performance
+    // priority for the time being.
+    while (!IsDebuggerPresent ())
+        Sleep (100);
+}
+
+
+//-----------------------------------------------------------------------------
+void
+prepare_debugger (void)
+{
+    if (nullptr == LoadLibrary("exchndl.dll")) {
+        LOG_WARNING("Emergency debugger not loaded: %s", util::win32_error ());
+    }
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+void
+enable_fpe (void)
+{
+    LOG_WARN ("Non-Linux exception code is broken under current GCC.");
+//    _clearfp();
+//    unsigned int ignored;
+//    _controlfp_s (&ignored, _MCW_EM, _MCW_EM);
+}
+
+
+//-----------------------------------------------------------------------------
+void
+disable_fpe (void)
+{
+    LOG_WARN ("Non-Linux exception code is broken under current GCC.");
+//    _clearfp();
+//    unsigned int ignored;
+//    _controlfp_s (&ignored, 0, _MCW_EM);
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+#include <io.h>
+#include <fcntl.h>
+
+void
+force_console (void)
+{
+    if (!AttachConsole (ATTACH_PARENT_PROCESS))
+        return;
+
+    auto out_handle = GetStdHandle (STD_OUTPUT_HANDLE);
+    auto err_handle = GetStdHandle (STD_ERROR_HANDLE);
+    auto in_handle  = GetStdHandle (STD_INPUT_HANDLE);
+
+    auto out_fd = _open_osfhandle (reinterpret_cast<intptr_t> (out_handle), _O_TEXT);
+    auto err_fd = _open_osfhandle (reinterpret_cast<intptr_t> (err_handle), _O_TEXT);
+    auto in_fd  = _open_osfhandle (reinterpret_cast<intptr_t> (in_handle),  _O_TEXT);
+
+    auto out_file = _fdopen (out_fd, "w");
+    auto err_file = _fdopen (err_fd, "w");
+    auto in_file  = _fdopen (in_fd,  "r");
+
+    /// FILE objects are not reassignable, but Windows doesn't leave us much
+    /// choice here.
+    *stdout = *out_file;
+    *stderr = *err_file;
+    *stdin  = *in_file;
+
+    setvbuf (stdout, NULL, _IONBF, 0);
+    setvbuf (stderr, NULL, _IONBF, 0);
+    setvbuf (stdin,  NULL, _IONBF, 0);
+
+    ios::sync_with_stdio ();
+
+    // Windows doesn't give an immediate newline when an application is run
+    // from a console, so we provide one here for sanity.
+    std::cout << "\n";
+    std::cerr << "Console installed\n";
+}