ircd: Add support for configurable soft-assertions.

configure.ac

@@ -184,6 +184,34 @@ AM_COND_IF(ASSERT,
 	CPPDEFINE([NDEBUG])
 ])
 
+dnl
+dnl Switch to control the action of assert()
+dnl
+
+AC_MSG_CHECKING(whether to change the behavior of assertions)
+AC_ARG_WITH(assert, AC_HELP_STRING([--with-assert[[[=trap]]]], [Soften assertion behavior]),
+[
+	assert_type=$withval
+	AC_MSG_RESULT([yes])
+	AC_SUBST(ASSERT_TYPE, $assert_type)
+], [
+	AM_COND_IF(DEBUG,
+	[
+		assert_type="trap"
+		AC_MSG_RESULT([no, defaulting to "$assert_type"])
+		AC_SUBST(ASSERT_TYPE, $assert_type)
+	], [
+		AC_MSG_RESULT([no])
+	])
+])
+
+AM_COND_IF(ASSERT,
+[
+	if [[ ! -z "$assert_type" ]]; then
+		RB_DEFINE_UNQUOTED([ASSERT], ["$assert_type"], [Assertion behavior])
+	fi
+])
+
 dnl
 dnl Explicit optimize switch for enabling optimization when using --enable-debug
 dnl
@@ -616,6 +644,7 @@ RB_CHK_SYSHEADER(stdarg.h, [STDARG_H])
 dnl libc++
 RB_CHK_SYSHEADER(cstddef, [CSTDDEF])
 RB_CHK_SYSHEADER(cstdint, [CSTDINT])
+RB_CHK_SYSHEADER(cstdlib, [CSTDLIB])
 RB_CHK_SYSHEADER(limits, [LIMITS])
 RB_CHK_SYSHEADER(type_traits, [TYPE_TRAITS])
 RB_CHK_SYSHEADER(typeindex, [TYPEINDEX])
@@ -1582,7 +1611,7 @@ echo "Linux AIO support ................. $aio"
 echo "IPv6 support ...................... $ipv6"
 echo "Precompiled headers ............... $build_pch"
 echo "Developer debug ................... $debug"
-echo "Developer assert .................. $assert"
+echo "Developer assert .................. $assert ($assert_type)"
 echo "Optimized build ................... $optimize"
 echo "Link-time optimized ............... $lto"
 echo "Optimization level ................ $optimize_level"

include/ircd/assert.h

@@ -0,0 +1,39 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+// This header allows for the use of soft-assertions. It is included before
+// the standard <assert.h> and these declarations will take precedence.
+//
+// These declarations exist because the system declarations may have
+// __attribute__((noreturn)) and our only modification here is to remove
+// that. Alternative definitions to the standard library also exist in
+// ircd/assert.cc
+
+#if defined(RB_ASSERT) && !defined(NDEBUG)
+#define _ASSERT_H_DECLS
+
+extern "C" void
+__assert_fail(const char *__assertion,
+              const char *__file,
+              unsigned int __line,
+              const char *__function);
+
+extern "C" void
+__assert_perror_fail(int __errnum,
+                     const char *__file,
+                     unsigned int __line,
+                     const char *__function);
+
+extern "C" void
+__assert(const char *__assertion,
+         const char *__file,
+         int __line);
+
+#endif

include/ircd/ircd.h

@@ -12,6 +12,7 @@
 
 // Generated by ./configure
 #include "config.h"
+#include "assert.h"
 #include "stdinc.h"
 #include "string_view.h"
 #include "vector_view.h"

include/ircd/logger.h

@@ -100,7 +100,7 @@ struct ircd::log::log
   public:
 	template<class... args> void operator()(const level &, const string_view &fmt, args&&...);
 
-	#if RB_LOG_LEVEL >= 0 && !defined(NDEBUG)
+	#if RB_LOG_LEVEL >= 0 && !defined(NDEBUG) && !defined(RB_ASSERT)
 	template<class... args> [[noreturn]] void critical(const string_view &fmt, args&&...);
 	#elif RB_LOG_LEVEL >= 0
 	template<class... args> void critical(const string_view &fmt, args&&...);
@@ -398,18 +398,30 @@ struct ircd::log::error
 #if RB_LOG_LEVEL >= 0 && !defined(NDEBUG)
 struct ircd::log::critical
 {
-	template<class... args> [[noreturn]]
+	template<class... args>
+	#if !defined(RB_ASSERT)
+	[[noreturn]]
+	#endif
 	critical(const log &log, const string_view &fmt, args&&... a)
 	{
 		vlog(log, level::CRITICAL, fmt, va_rtti{std::forward<args>(a)...});
-		ircd::terminate();
+
+		#ifndef NDEBUG
+		__assert_fail("critical", "", 0, "");
+		#endif
 	}
 
-	template<class... args> [[noreturn]]
+	template<class... args>
+	#if !defined(RB_ASSERT)
+	[[noreturn]]
+	#endif
 	critical(const string_view &fmt, args&&... a)
 	{
 		vlog(general, level::CRITICAL, fmt, va_rtti{std::forward<args>(a)...});
-		ircd::terminate();
+
+		#ifndef NDEBUG
+		__assert_fail("critical", "", 0, "");
+		#endif
 	}
 };
 #elif RB_LOG_LEVEL >= 0
@@ -570,7 +582,7 @@ ircd::log::log::critical(const string_view &fmt,
 	operator()(level::CRITICAL, fmt, va_rtti{std::forward<args>(a)...});
 
 	#ifndef NDEBUG
-	ircd::terminate();;
+	__assert_fail("critical", "", 0, "");
 	#endif
 }
 #else

include/ircd/stdinc.h

@@ -39,6 +39,7 @@ extern "C"
 
 #include <RB_INC_CSTDDEF
 #include <RB_INC_CSTDINT
+#include <RB_INC_CSTDLIB
 #include <RB_INC_LIMITS
 #include <RB_INC_TYPE_TRAITS
 #include <RB_INC_TYPEINDEX

ircd/Makefile.am

@@ -100,6 +100,7 @@ libircd_la_LIBADD = \
 # the units that compile spirit grammars otherwise they thrash weaker
 # systems.
 libircd_la_SOURCES =   \
+	assert.cc          \
 	info.cc            \
 	allocator.cc       \
 	exception.cc       \

ircd/assert.cc

@@ -0,0 +1,91 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#if !defined(NDEBUG) && defined(RB_ASSERT)
+#include <RB_INC_SIGNAL_H
+#endif
+
+#if !defined(NDEBUG) && defined(RB_ASSERT)
+void
+__assert_fail(const char *__assertion,
+              const char *__file,
+              unsigned int __line,
+              const char *__function)
+{
+	if(strcmp(__assertion, "critical") != 0)
+		fprintf(stderr, "\nassertion failed [%s +%u] %s :%s\n",
+		        __file,
+		        __line,
+		        __function,
+		        __assertion);
+
+	if(strcmp(RB_ASSERT, "trap") == 0)
+		__asm__ volatile ("int $3");
+
+	else if(strcmp(RB_ASSERT, "quit") == 0)
+		ircd::quit();
+
+	#if defined(HAVE_EXCEPTION)
+	else if(strcmp(RB_ASSERT, "term") == 0)
+	{
+		std::terminate();
+		__builtin_unreachable();
+	}
+	#endif
+
+	#if defined(HAVE_CSTDLIB)
+	else if(strcmp(RB_ASSERT, "abort") == 0)
+	{
+		abort();
+		__builtin_unreachable();
+	}
+	#endif
+
+	#if defined(HAVE_SIGNAL_H)
+	else if(strcmp(RB_ASSERT, "SIGTRAP") == 0)
+		raise(SIGTRAP);
+	#endif
+
+	#if defined(HAVE_SIGNAL_H)
+	else if(strcmp(RB_ASSERT, "SIGQUIT") == 0)
+		raise(SIGSTOP);
+	#endif
+
+	#if defined(HAVE_SIGNAL_H)
+	else if(strcmp(RB_ASSERT, "SIGQUIT") == 0)
+		raise(SIGQUIT);
+	#endif
+
+	else __builtin_trap();
+}
+#endif
+
+#if !defined(NDEBUG) && defined(RB_ASSERT)
+void
+__assert_perror_fail(int __errnum,
+                     const char *__file,
+                     unsigned int __line,
+                     const char *__function)
+{
+	char buf[32];
+	snprintf(buf, sizeof(buf), "perror #%d: ", __errnum);
+	__assert_fail(buf, __file, __line, __function);
+}
+#endif
+
+#if !defined(NDEBUG) && defined(RB_ASSERT)
+void
+__assert(const char *__assertion,
+         const char *__file,
+         int __line)
+{
+	__assert_fail(__assertion, __file, __line, "<no function>");
+}
+#endif

ircd/exception.cc

@@ -25,7 +25,7 @@ noexcept
 }
 
 void
-#ifndef NDEBUG
+#if !defined(NDEBUG) && !defined(RB_ASSERT)
 __attribute__((noreturn))
 #endif
 ircd::panicking(const std::exception_ptr &eptr)
@@ -41,7 +41,7 @@ noexcept
 /// log a critical message, which is actually what triggers a termination when
 /// assertions are enabled (!NDEBUG) otherwise a no-op.
 void
-#ifndef NDEBUG
+#if !defined(NDEBUG) && !defined(RB_ASSERT)
 __attribute__((noreturn))
 #endif
 ircd::panicking(const std::exception &e)