From 1300e68fa5afd244912307176bb73203c0b15b29 Mon Sep 17 00:00:00 2001
From: axel <axel@liljencrantz.se>
Date: Sat, 20 Jan 2007 12:36:49 +1000
Subject: [PATCH] Add support for backtraces - if the compiler and libc version
 supports it (probably only glibc/gcc) then a stack trace is printed on
 serious bugs

darcs-hash:20070120023649-ac50b-5efa310bea0deddfa1d8dfca1000163eee89c7cb.gz
---
 common.c     | 26 ++++++++++++++++++++++++++
 common.h     | 28 +++++++++++++++++-----------
 configure.ac | 12 +++++++++---
 env.c        |  2 +-
 fallback.c   | 13 +++++++++++++
 main.c       |  1 -
 6 files changed, 66 insertions(+), 16 deletions(-)

diff --git a/common.c b/common.c
index 1e42cb731..0b7a26aed 100644
--- a/common.c
+++ b/common.c
@@ -44,6 +44,10 @@ parts of fish.
 #include <sys/time.h>
 #include <fcntl.h>
 
+#ifdef HAVE_EXECINFO_H
+#include <execinfo.h>
+#endif
+
 #ifndef HOST_NAME_MAX
 /**
    Maximum length of hostname return. It is ok if this is too short,
@@ -110,6 +114,28 @@ static struct winsize termsize;
 */
 static string_buffer_t *setlocale_buff=0;
 
+
+void show_stackframe() 
+{
+	void *trace[32];
+	char **messages = (char **)NULL;
+	int i, trace_size = 0;
+
+	trace_size = backtrace(trace, 32);
+	messages = backtrace_symbols(trace, trace_size);
+
+	if( messages )
+	{
+		debug( 0, L"Backtrace:" );
+		for( i=0; i<trace_size; i++ )
+		{
+			fwprintf( stderr, L"%s\n", messages[i]);
+		}
+		free( messages );
+	}
+}
+
+
 wchar_t **list_to_char_arr( array_list_t *l )
 {
 	wchar_t ** res = malloc( sizeof(wchar_t *)*(al_get_count( l )+1) );
diff --git a/common.h b/common.h
index af3a723ef..5b56da736 100644
--- a/common.h
+++ b/common.h
@@ -86,9 +86,22 @@ extern wchar_t *program_name;
 			   __func__,												\
 			   #arg );													\
 		bugreport();													\
+		show_stackframe();												\
 		return retval;													\
 	}
 
+/**
+   Cause fish to crash. If supported, print a backtrace first.
+*/
+#define CRASH()									\
+	{											\
+		char c;									\
+		show_stackframe();						\
+		read( 0, &c, 1 );						\
+		exit(1 );								\
+	}											\
+		
+
 /**
    Exit program at once, leaving an error message about running out of memory.
 */
@@ -98,17 +111,7 @@ extern wchar_t *program_name;
 				  L"fish: Out of memory on line %d of file %s, shutting down fish\n", \
 				  __LINE__,												\
 				  __FILE__ );											\
-		exit(1);														\
-	}
-
-/**
-   Cause fish to crash. This should only be used for debugging. If
-   this function is ever called in shipped code, this is a bug.
-*/
-#define CRASH()									\
-	{											\
-		int *n = 0;								\
-		*n = 1;									\
+		CRASH();														\
 	}
 
 /**
@@ -122,6 +125,7 @@ extern wchar_t *program_name;
 			   _( L"function %s called while blocking signals. " ),		\
 			   __func__);												\
 		bugreport();													\
+		show_stackframe();												\
 		return retval;													\
 	}
 		
@@ -137,6 +141,8 @@ extern wchar_t *program_name;
 #define N_(wstr) wstr
 
 
+void show_stackframe();
+
 /**
    Take an array_list_t containing wide strings and converts them to a
    single null-terminated wchar_t **. The array is allocated using
diff --git a/configure.ac b/configure.ac
index 64b027af8..3abe2666e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -279,6 +279,12 @@ if test "$CC" = gcc; then
 
 	CFLAGS="$CFLAGS -Wall"
 
+	#
+	# This is needed in order to get the really cool backtraces
+	#
+
+	LDFLAGS="$LDFLAGS -rdynamic"
+
 fi
 
 
@@ -451,7 +457,7 @@ AC_SEARCH_LIBS( iconv_open, iconv, , [AC_MSG_ERROR([Could not find an iconv impl
 # Check presense of various header files
 #
 
-AC_CHECK_HEADERS([getopt.h termio.h sys/resource.h term.h ncurses/term.h ncurses.h curses.h stropts.h siginfo.h sys/select.h sys/ioctl.h sys/termios.h libintl.h])
+AC_CHECK_HEADERS([getopt.h termio.h sys/resource.h term.h ncurses/term.h ncurses.h curses.h stropts.h siginfo.h sys/select.h sys/ioctl.h sys/termios.h libintl.h execinfo.h])
 
 AC_CHECK_HEADER(
 	[regex.h],
@@ -594,8 +600,8 @@ fi
 
 AC_CHECK_FUNCS( wcsdup wcsndup wcslen wcscasecmp wcsncasecmp fwprintf )
 AC_CHECK_FUNCS( futimes wcwidth wcswidth wcstok fputwc fgetwc )
-AC_CHECK_FUNCS( wcstol wcslcat wcslcpy lrand48_r killpg gettext dcgettext )
-
+AC_CHECK_FUNCS( wcstol wcslcat wcslcpy lrand48_r killpg gettext )
+AC_CHECK_FUNCS( dcgettext backtrace backtrace_symbols)
 
 #
 # The Makefile also needs to know if we have gettext, so it knows if
diff --git a/env.c b/env.c
index 9c7cee804..5d5175c97 100644
--- a/env.c
+++ b/env.c
@@ -665,7 +665,7 @@ int env_set( const wchar_t *key,
 
 	event_t ev;
 	int is_universal = 0;	
-
+	
 	CHECK( key, ENV_INVALID );
 		
 	if( (var_mode & ENV_USER ) && 
diff --git a/fallback.c b/fallback.c
index 8153b713a..f6ce7e6fc 100644
--- a/fallback.c
+++ b/fallback.c
@@ -1091,3 +1091,16 @@ int getopt_long( int argc,
 
 #endif
 
+#ifndef HAVE_BACKTRACE
+int backtrace (void **buffer, int size)
+{
+	return 0;
+}
+#endif
+
+#ifndef HAVE_BACKTRACE_SYMBOLS
+char ** backtrace_symbols (void *const *buffer, int size)
+{
+	return 0;
+}
+#endif
diff --git a/main.c b/main.c
index 2ce441993..57556e3e8 100644
--- a/main.c
+++ b/main.c
@@ -312,7 +312,6 @@ int main( int argc, char **argv )
 	reader_init();
 	history_init();
 
-
 	if( read_init() )
 	{
 		if( cmd != 0 )