[patch] Patch for 18.59: 05_all_bss-heap-gap.patch

05_all_bss-heap-gap.patch (text/plain), 4.31 KB, created by Ulrich Müller on 2008-05-11 00:36:17 UTC

Prereq: 2007-01-30
diff -ur emacs-18.59-orig/src/ChangeLog emacs-18.59/src/ChangeLog
--- emacs-18.59-orig/src/ChangeLog	2007-01-30 01:00:00.000000000 +0100
+++ emacs-18.59/src/ChangeLog	2008-05-11 02:12:37.000000000 +0200
@@ -1,3 +1,18 @@
[phone]  Ulrich Mueller  <[e-mail]>
+
+	* emacs.c: Handle gap between end of BSS and heap, backported
+	from Emacs 22. Original changes by Jan Djarv and Masatake YAMATO.
+	This fixes dumping on Linux 2.6.25.
+	(my_heap_start, heap_bss_diff, MAX_HEAP_BSS_DIFF): New variables
+	and constant.
+	(main): Calculate heap_bss_diff.  If we are dumping and the
+	heap_bss_diff is greater than MAX_HEAP_BSS_DIFF, set PER_LINUX32
+	and ADD_NO_RANDOMIZE and exec ourself again.
+
+	* lastfile.c: (my_endbss, my_endbss_static) New variables.
+
+	* s-linux.h (HAVE_PERSONALITY_LINUX32): Define.
+
 2007-01-30  Ulrich Mueller  <[e-mail]>
 
 	* x11term.c (internal_socket_read): Handle XK_BackSpace key.
diff -ur emacs-18.59-orig/src/emacs.c emacs-18.59/src/emacs.c
--- emacs-18.59-orig/src/emacs.c	2007-01-29 21:47:56.000000000 +0100
+++ emacs-18.59/src/emacs.c	2008-05-11 01:49:58.000000000 +0200
@@ -78,6 +78,10 @@
 #endif
 #endif
 
+#ifdef HAVE_PERSONALITY_LINUX32
+#include <sys/personality.h>
+#endif
+
 #ifndef O_RDWR
 #define O_RDWR 2
 #endif
@@ -110,6 +114,16 @@
 int xargc;
 #endif /* HAVE_X_WINDOWS */
 
+/* The address where the heap starts (from the first sbrk (0) call).  */
+static void *my_heap_start;
+
+/* The gap between BSS end and heap start as far as we can tell.  */
+static unsigned long heap_bss_diff;
+
+/* If the gap between BSS end and heap start is larger than this we try to
+   work around it, and if that fails, output a warning in dump-emacs.  */
+#define MAX_HEAP_BSS_DIFF (1024*1024)
+
 #ifdef USG_SHARED_LIBRARIES
 /* If nonzero, this is the place to put the end of the writable segment
    at startup.  */
@@ -241,7 +255,46 @@
   int skip_args = 0;
   extern int errno;
   extern void malloc_warning ();
+  extern char *sbrk ();
 
+  if (!initialized)
+    {
+      extern char my_endbss[];
+      extern char *my_endbss_static;
+
+      if (my_heap_start == 0)
+        my_heap_start = sbrk (0);
+
+      heap_bss_diff = (char *)my_heap_start
+	- (my_endbss > my_endbss_static ? my_endbss : my_endbss_static);
+    }
+
+#ifdef HAVE_PERSONALITY_LINUX32
+  /* See if there is a gap between the end of BSS and the heap.
+     In that case, set personality and exec ourself again.  */
+  if (!initialized
+      && strcmp (argv[argc-1], "dump") == 0
+      && heap_bss_diff > MAX_HEAP_BSS_DIFF)
+    {
+      if (! getenv ("EMACS_HEAP_EXEC"))
+	{
+	  /* Set this so we only do this once.  */
+	  putenv("EMACS_HEAP_EXEC=true");
+
+	  /* A flag to turn off address randomization which is introduced
+	   in linux kernel shipped with fedora core 4 */
+#define ADD_NO_RANDOMIZE 0x0040000
+	  personality (PER_LINUX32 | ADD_NO_RANDOMIZE);
+#undef  ADD_NO_RANDOMIZE
+
+	  execvp (argv[0], argv);
+
+	  /* If the exec fails, try to dump anyway.  */
+	  perror ("execvp");
+	}
+    }
+#endif /* HAVE_PERSONALITY_LINUX32 */
+
 /* Map in shared memory, if we are using that.  */
 #ifdef HAVE_SHM
   if (argc > 1 && !strcmp (argv[1], "-nl"))
diff -ur emacs-18.59-orig/src/lastfile.c emacs-18.59/src/lastfile.c
--- emacs-18.59-orig/src/lastfile.c	1991-03-31 00:05:55.000000000 +0100
+++ emacs-18.59/src/lastfile.c	2008-05-11 01:52:45.000000000 +0200
@@ -41,3 +41,13 @@
 #endif
 
 char my_edata = 0;
+
+/* Help unexec locate the end of the .bss area used by Emacs (which
+   isn't always a separate section in NT executables).  */
+char my_endbss[1];
+
+/* The Alpha MSVC linker globally segregates all static and public bss
+   data, so we must take both into account to determine the true extent
+   of the bss area used by Emacs.  */
+static char _my_endbss[1];
+char * my_endbss_static = _my_endbss;
diff -ur emacs-18.59-orig/src/s-linux.h emacs-18.59/src/s-linux.h
--- emacs-18.59-orig/src/s-linux.h	2007-01-29 21:47:56.000000000 +0100
+++ emacs-18.59/src/s-linux.h	2008-05-11 01:58:40.000000000 +0200
@@ -161,6 +161,7 @@
 #define HAVE_SYS_SIGLIST	/* we have a (non-standard) sys_siglist */
 #define SYS_SIGLIST_DECLARED
 #define HAVE_GETWD		/* cure conflict with getcwd? */
+#define HAVE_PERSONALITY_LINUX32 /* personality LINUX32 can be set */
 
 #define NO_SIOCTL_H		/* don't have sioctl.h */
 #define SYSV_SYSTEM_DIR		/* use dirent.h */