engine: platform: posix: use glibc-based backtrace implementation for…

… crash handling, if execinfo.h can be found

engine/platform/posix/crash_glibc.c

@@ -0,0 +1,82 @@
+/*
+crashhandler.c - advanced crashhandler
+Copyright (C) 2016 Mittorn
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+*/
+
+// on Glibc (which potentially might not be only Linux) systems we
+// have backtrace() and backtrace_symbols() calls, which replace for us
+// platform-specific code
+#if HAVE_EXECINFO
+#include "common.h"
+#include <execinfo.h>
+#include <signal.h>
+
+void Sys_Crash( int signal, siginfo_t *si, void *context )
+{
+	char message[8192];
+	int len, logfd, i = 0;
+	int size;
+	void *addrs[16];
+	char **syms;
+
+	// safe actions first, stack and memory may be corrupted
+	len = Q_snprintf( message, sizeof( message ), "Ver: " XASH_ENGINE_NAME " " XASH_VERSION " (build %i-%s, %s-%s)\n",
+					  Q_buildnum(), g_buildcommit, Q_buildos(), Q_buildarch() );
+
+#if !XASH_FREEBSD && !XASH_NETBSD && !XASH_OPENBSD
+	len += Q_snprintf( message + len, sizeof( message ) - len, "Crash: signal %d errno %d with code %d at %p %p\n", signal, si->si_errno, si->si_code, si->si_addr, si->si_ptr );
+#else
+	len += Q_snprintf( message + len, sizeof( message ) - len, "Crash: signal %d errno %d with code %d at %p\n", signal, si->si_errno, si->si_code, si->si_addr );
+#endif
+
+	write( STDERR_FILENO, message, len );
+
+	// flush buffers before writing directly to descriptors
+	fflush( stdout );
+	fflush( stderr );
+
+	// now get log fd and write trace directly to log
+	logfd = Sys_LogFileNo();
+	write( logfd, message, len );
+
+	size = backtrace( addrs, sizeof( addrs ) / sizeof( addrs[0] ));
+	syms = backtrace_symbols( addrs, size );
+
+	for( i = 0; i < size && syms; i++ )
+	{
+		size_t symlen = Q_strlen( syms[i] );
+		char ch = '\n';
+
+		write( logfd, syms[i], symlen );
+		write( logfd, &ch, 1 );
+
+		len += Q_snprintf( message + len, sizeof( message ) - len, "%2d: %s\n", i, syms[i] );
+	}
+
+	// put MessageBox as Sys_Error
+	Msg( "%s\n", message );
+#ifdef XASH_SDL
+	SDL_SetWindowGrab( host.hWnd, SDL_FALSE );
+#endif
+	host.crashed = true;
+	Platform_MessageBox( "Xash Error", message, false );
+
+	// log saved, now we can try to save configs and close log correctly, it may crash
+	if( host.type == HOST_NORMAL )
+		CL_Crashed();
+	host.status = HOST_CRASHED;
+
+	Sys_Quit( "crashed" );
+}
+
+#endif // HAVE_EXECINFO

engine/platform/posix/crash_posix.c

@@ -26,15 +26,18 @@ GNU General Public License for more details.
 #include <sys/mman.h>
 #include "library.h"
 
+void Sys_Crash( int signal, siginfo_t *si, void *context );
+static struct sigaction oldFilter;
+
+#if !HAVE_EXECINFO
+
 #define STACK_BACKTRACE_STR     "Stack backtrace:\n"
 #define STACK_DUMP_STR          "Stack dump:\n"
 
 #define STACK_BACKTRACE_STR_LEN ( sizeof( STACK_BACKTRACE_STR ) - 1 )
 #define STACK_DUMP_STR_LEN      ( sizeof( STACK_DUMP_STR ) - 1 )
 #define ALIGN( x, y ) (((uintptr_t) ( x ) + (( y ) - 1 )) & ~(( y ) - 1 ))
 
-static struct sigaction oldFilter;
-
 static int Sys_PrintFrame( char *buf, int len, int i, void *addr )
 {
 	Dl_info dlinfo;
@@ -53,7 +56,7 @@ static int Sys_PrintFrame( char *buf, int len, int i, void *addr )
 		return Q_snprintf( buf, len, "%2d: %p\n", i, addr ); // print only address
 }
 
-static void Sys_Crash( int signal, siginfo_t *si, void *context)
+void Sys_Crash( int signal, siginfo_t *si, void *context )
 {
 	void *pc = NULL, **bp = NULL, **sp = NULL; // this must be set for every OS!
 	char message[8192];
@@ -200,6 +203,8 @@ static void Sys_Crash( int signal, siginfo_t *si, void *context)
 	Sys_Quit( "crashed" );
 }
 
+#endif // !HAVE_EXECINFO
+
 void Sys_SetupCrashHandler( void )
 {
 	struct sigaction act = { 0 };

engine/wscript

@@ -111,6 +111,8 @@ def configure(conf):
 	if hasattr(conf.options, 'DLLEMU'):
 		conf.define_cond('XASH_DLL_LOADER', conf.options.DLLEMU)
 
+	conf.check_cc(header_name='execinfo.h', mandatory=False, define_name='HAVE_EXECINFO')
+
 	conf.define('ENGINE_DLL', 1)
 	conf.define_cond('XASH_ENGINE_TESTS', conf.options.ENGINE_TESTS)
 	conf.define_cond('XASH_STATIC_LIBS', conf.env.STATIC_LINKING)