[PATCH] unexec() for Cygwin port

[PATCH] unexec() for Cygwin port

[Joe Buehler]

[resend: forgot the patch...]

Below is a final set of patches to complete the Cygwin port for 21.3.50
that I did about a year ago.  These patches add unexec() support for
Cygwin, which is currently missing in CVS.

The original unexec() code I submitted was from xemacs and was rejected
for licensing reasons.  The below code is a rewrite by me that is also
much simpler and easier to understand than the xemacs code.

Please commit it to CVS as soon as possible...

Thanks.
-- 
Joe Buehler

Index: lisp/ChangeLog
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/ChangeLog,v
retrieving revision 1.5775
diff -u -r1.5775 ChangeLog
--- lisp/ChangeLog	18 Mar 2004 03:07:38 -0000	1.5775
+++ lisp/ChangeLog	29 Mar 2004 13:22:37 -0000
@@ -1,3 +1,7 @@
+2004-03-29  Joe Buehler  <jbuehler@hekiman.com>
+
+	* loadup.el: added cygwin to system-type list, for unexec() support.
+
  2004-03-17  Luc Teirlinck  <teirllm@auburn.edu>

  	* simple.el (clone-buffer): Doc fix.
Index: lisp/loadup.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/loadup.el,v
retrieving revision 1.133
diff -u -r1.133 loadup.el
--- lisp/loadup.el	8 Nov 2003 01:39:07 -0000	1.133
+++ lisp/loadup.el	29 Mar 2004 13:22:39 -0000
@@ -330,7 +330,7 @@
        (dump-emacs "emacs" "temacs")
        (message "%d pure bytes used" pure-bytes-used)
        ;; Recompute NAME now, so that it isn't set when we dump.
-      (if (not (memq system-type '(ms-dos windows-nt)))
+      (if (not (memq system-type '(ms-dos windows-nt cygwin)))
  	  (let ((name (concat "emacs-" emacs-version)))
  	    (while (string-match "[^-+_.a-zA-Z0-9]+" name)
  	      (setq name (concat (downcase (substring name 0 (match-beginning 0)))
Index: src/ChangeLog
===================================================================
RCS file: /cvsroot/emacs/emacs/src/ChangeLog,v
retrieving revision 1.3586
diff -u -r1.3586 ChangeLog
--- src/ChangeLog	18 Mar 2004 02:59:33 -0000	1.3586
+++ src/ChangeLog	29 Mar 2004 13:22:45 -0000
@@ -1,3 +1,17 @@
+2004-03-29  Joe Buehler  <jbuehler@hekimian.com>
+
+	* s/cygwin.h: changes for Cygwin unexec() support, changes in
+	Cygwin itself.
+
+	* puresize.h: set up PURE_P() for Cygwin unexec() support
+
+	* lastfile.c: define my_endbss[] for Cygwin unexec() support.
+
+	* gmalloc.c (__default_morecore): use bss_sbrk(), not __sbrk(),
+	before Cygwin unexec.
+
+	* Makefile.in: link changes for Cygwin unexec() support.
+
  2004-03-17  Stefan Monnier  <monnier@iro.umontreal.ca>

  	* fileio.c (Fread_file_name): Set completion-ignore-case for
Index: src/Makefile.in
===================================================================
RCS file: /cvsroot/emacs/emacs/src/Makefile.in,v
retrieving revision 1.295
diff -u -r1.295 Makefile.in
--- src/Makefile.in	14 Mar 2004 18:43:56 -0000	1.295
+++ src/Makefile.in	29 Mar 2004 13:22:56 -0000
@@ -564,6 +564,10 @@
  #endif
  #endif

+#ifdef CYGWIN
+CYGWIN_OBJ = sheap.o
+#endif
+
  #ifdef HAVE_CARBON
  mac = $(dot)$(dot)/mac/
  MAC_OBJ = mac.o macterm.o macfns.o macmenu.o fontset.o fringe.o image.o
@@ -586,7 +590,7 @@
  	process.o callproc.o \
  	region-cache.o sound.o atimer.o \
  	doprnt.o strftime.o intervals.o textprop.o composite.o md5.o \
-	$(MSDOS_OBJ) $(MAC_OBJ)
+	$(MSDOS_OBJ) $(MAC_OBJ) $(CYGWIN_OBJ)

  /* Object files used on some machine or other.
     These go in the DOC file on all machines
@@ -623,8 +627,6 @@
  rallocobj = ralloc.o
  #endif

-mallocobj = $(gmallocobj) $(rallocobj) vm-limit.o
-
  #endif /* SYSTEM_MALLOC */


@@ -643,7 +645,11 @@

  /* define otherobj as list of object files that make-docfile
     should not be told about.  */
-otherobj= $(termcapobj) lastfile.o $(mallocobj) $(allocaobj) $(widgetobj) $(LIBOBJS)
+#ifdef CYGWIN
+otherobj= $(termcapobj) $(gmallocobj) $(rallocobj) lastfile.o vm-limit.o $(allocaobj) $(widgetobj) $(LIBOBJS)
+#else
+otherobj= $(termcapobj) lastfile.o $(gmallocobj) $(rallocobj) vm-limit.o $(allocaobj) $(widgetobj) $(LIBOBJS)
+#endif

  #ifdef HAVE_MOUSE
  #define MOUSE_SUPPORT ${lispsource}mouse.elc \
Index: src/gmalloc.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/gmalloc.c,v
retrieving revision 1.14
diff -u -r1.14 gmalloc.c
--- src/gmalloc.c	1 Sep 2003 15:45:52 -0000	1.14
+++ src/gmalloc.c	29 Mar 2004 13:22:56 -0000
@@ -352,6 +352,10 @@
  #include <errno.h>

  /* How to really get more memory.  */
+#if defined(CYGWIN)
+extern __ptr_t bss_sbrk PP ((ptrdiff_t __size));
+extern int bss_sbrk_did_unexec;
+#endif
  __ptr_t (*__morecore) PP ((ptrdiff_t __size)) = __default_morecore;

  /* Debugging hook for `malloc'.  */
@@ -1572,7 +1576,13 @@
  __default_morecore (increment)
       __malloc_ptrdiff_t increment;
  {
-  __ptr_t result = (__ptr_t) __sbrk (increment);
+  __ptr_t result;
+#if defined(CYGWIN)
+  if (!bss_sbrk_did_unexec) {
+    return bss_sbrk(increment);
+  }
+#endif
+  result = (__ptr_t) __sbrk (increment);
    if (result == (__ptr_t) -1)
      return NULL;
    return result;
Index: src/lastfile.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/lastfile.c,v
retrieving revision 1.8
diff -u -r1.8 lastfile.c
--- src/lastfile.c	1 Sep 2003 15:45:56 -0000	1.8
+++ src/lastfile.c	29 Mar 2004 13:22:56 -0000
@@ -40,7 +40,7 @@

  char my_edata[] = "End of Emacs initialized data";

-#ifdef WINDOWSNT
+#if defined(WINDOWSNT) || defined(CYGWIN)
  /* 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];
Index: src/puresize.h
===================================================================
RCS file: /cvsroot/emacs/emacs/src/puresize.h,v
retrieving revision 1.70
diff -u -r1.70 puresize.h
--- src/puresize.h	1 Sep 2003 15:45:56 -0000	1.70
+++ src/puresize.h	29 Mar 2004 13:22:56 -0000
@@ -68,7 +68,7 @@
  \f
  /* Define PURE_P.  */

-#ifdef VIRT_ADDR_VARIES
+#if defined(VIRT_ADDR_VARIES) || defined(CYGWIN)
  /* For machines like APOLLO where text and data can go anywhere
     in virtual memory.  */

Index: src/s/cygwin.h
===================================================================
RCS file: /cvsroot/emacs/emacs/src/s/cygwin.h,v
retrieving revision 1.3
diff -u -r1.3 cygwin.h
--- src/s/cygwin.h	1 Sep 2003 15:45:58 -0000	1.3
+++ src/s/cygwin.h	29 Mar 2004 13:22:56 -0000
@@ -115,10 +115,8 @@
  #define PENDING_OUTPUT_COUNT(FILE) ((FILE)->_p - (FILE)->_bf._base)
  #define GETPGRP_NO_ARG 1
  #define SYSV_SYSTEM_DIR 1
-/* -lutil comes from inetutils and has pty functions in it */
-#define LIBS_SYSTEM -lutil
-/* undumping is not implemented yet */
-#define CANNOT_DUMP 1
+#define LIB_STANDARD_LIBSRC
+#define UNEXEC unexcw.o
  #define POSIX_SIGNALS 1
  /* force the emacs image to start high in memory, so dll relocation
     can put things in low memory without causing all sorts of grief for
--- ./src/sheap.c.~1~	2004-03-18 13:45:00.000000000 -0500
+++ ./src/sheap.c	2004-03-18 22:02:36.966248000 -0500
@@ -0,0 +1,96 @@
+/* simulate sbrk() with an array in .bss, for unexec() support for Cygwin
+   complete rewrite of xemacs Cygwin unexec() code
+
+   Copyright (C) 2004
+   Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs 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 2, or (at your option)
+any later version.
+
+GNU Emacs 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.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+#include <config.h>
+#include <stdio.h>
+#include "lisp.h"
+
+#include <unistd.h>
+
+#ifdef HAVE_X_WINDOWS
+#define STATIC_HEAP_SIZE	(7 * 1024 * 1024)
+#else
+#define STATIC_HEAP_SIZE	(6 * 1024 * 1024)
+#endif
+
+#define BLOCKSIZE 4096
+
+char bss_sbrk_buffer[STATIC_HEAP_SIZE];
+char *bss_sbrk_ptr;
+int bss_sbrk_did_unexec;
+
+void *
+bss_sbrk(ptrdiff_t request_size)
+{
+    if (!bss_sbrk_ptr)
+    {
+		bss_sbrk_ptr = bss_sbrk_buffer;
+#ifdef CYGWIN
+		sbrk(BLOCKSIZE);		/* force space for fork to work */
+#endif
+    }
+
+	if (!(int)request_size)
+	{
+		return(bss_sbrk_ptr);
+	}
+    else if (bss_sbrk_ptr + (int)request_size < bss_sbrk_buffer)
+    {
+		printf("attempt to free too much: avail %d used %d failed request %d\n",
+			   STATIC_HEAP_SIZE,
+			   bss_sbrk_ptr - bss_sbrk_buffer,
+			   (int)request_size);
+		exit(-1);
+		return 0;
+    }
+    else if (bss_sbrk_ptr + (int)request_size > bss_sbrk_buffer + STATIC_HEAP_SIZE)
+    {
+		printf("static heap exhausted: avail %d used %d failed request %d\n",
+			   STATIC_HEAP_SIZE,
+			   bss_sbrk_ptr - bss_sbrk_buffer,
+			   (int)request_size);
+		exit(-1);
+		return 0;
+    }
+    else if ((int)request_size < 0)
+	{
+		bss_sbrk_ptr += (int)request_size;
+		printf("freed size %d\n", request_size);
+		return bss_sbrk_ptr;
+	}
+    else
+    {
+		char *ret = bss_sbrk_ptr;
+		printf("allocated 0x%08x size %d\n", ret, request_size);
+		bss_sbrk_ptr += (int)request_size;
+		return ret;
+    }
+}
+
+void
+report_sheap_usage(int die_if_pure_storage_exceeded)
+{
+    char buf[200];
+    sprintf (buf, "Static heap usage: %d of %d bytes", bss_sbrk_ptr - bss_sbrk_buffer, STATIC_HEAP_SIZE);
+    message ("%s", buf);
+}
--- ./src/unexcw.c.~1~	2004-03-18 13:45:00.000000000 -0500
+++ ./src/unexcw.c	2004-03-19 08:50:13.138680000 -0500
@@ -0,0 +1,256 @@
+/* unexec() support for Cygwin
+   complete rewrite of xemacs Cygwin unexec() code
+
+   Copyright (C) 2004
+   Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs 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 2, or (at your option)
+any later version.
+
+GNU Emacs 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.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+#include <config.h>
+#include <lisp.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <a.out.h>
+#include <unistd.h>
+#include <assert.h>
+
+#define DOTEXE ".exe"
+
+extern int bss_sbrk_did_unexec;
+
+/* emacs symbols that indicate where bss and data end for emacs internals */
+extern char my_endbss[];
+extern char my_edata[];
+
+/*
+** header for Windows executable files
+*/
+typedef struct {
+	FILHDR file_header;
+	PEAOUTHDR file_optional_header;
+	SCNHDR section_header[32];
+} exe_header_t;
+
+/*
+** Read the header from the executable into memory so we can more easily access it.
+*/
+static exe_header_t *
+read_exe_header(int fd, exe_header_t *exe_header_buffer)
+{
+	int i;
+	int ret;
+
+	assert(fd >= 0);
+	assert(exe_header_buffer != 0);
+
+	ret = lseek(fd, 0L, SEEK_SET);
+	assert(ret != -1);
+
+	ret = read(fd, &exe_header_buffer->file_header, sizeof(exe_header_buffer->file_header));
+	assert(ret == sizeof(exe_header_buffer->file_header));
+
+	assert(exe_header_buffer->file_header.e_magic == 0x5a4d);
+	assert(exe_header_buffer->file_header.nt_signature == 0x4550);
+	assert(exe_header_buffer->file_header.f_magic == 0x014c);
+	assert(exe_header_buffer->file_header.f_nscns > 0);
+	assert(exe_header_buffer->file_header.f_nscns <= sizeof(exe_header_buffer->section_header)/sizeof(exe_header_buffer->section_header[0]));
+	assert(exe_header_buffer->file_header.f_opthdr > 0);
+
+	ret = read(fd, &exe_header_buffer->file_optional_header, sizeof(exe_header_buffer->file_optional_header));
+	assert(ret == sizeof(exe_header_buffer->file_optional_header));
+
+	assert(exe_header_buffer->file_optional_header.magic == 0x010b);
+
+	for (i=0; i<exe_header_buffer->file_header.f_nscns; ++i) {
+		ret = read(fd, &exe_header_buffer->section_header[i], sizeof(exe_header_buffer->section_header[i]));
+		assert(ret == sizeof(exe_header_buffer->section_header[i]));
+	}
+
+	return(exe_header_buffer);
+}
+
+/*
+** Fix the dumped emacs executable:
+**
+** - copy .data section data of interest from running executable into
+**   output .exe file
+**
+** - convert .bss section into an initialized data section (like
+**   .data) and copy .bss section data of interest from running
+**   executable into output .exe file
+*/
+static void
+fixup_executable(int fd)
+{
+	exe_header_t exe_header_buffer;
+	exe_header_t *exe_header;
+	int i;
+	int ret;
+	int found_data = 0;
+	int found_bss = 0;
+
+	exe_header = read_exe_header(fd, &exe_header_buffer);
+	assert(exe_header != 0);
+
+	assert(exe_header->file_header.f_nscns > 0);
+	for (i=0; i<exe_header->file_header.f_nscns; ++i) {
+		unsigned long start_address =
+			exe_header->section_header[i].s_vaddr +
+			exe_header->file_optional_header.ImageBase;
+		unsigned long end_address =
+			exe_header->section_header[i].s_vaddr +
+			exe_header->file_optional_header.ImageBase +
+			exe_header->section_header[i].s_paddr;
+		printf("%8s start 0x%08x end 0x%08x\n",
+			   exe_header->section_header[i].s_name,
+			   start_address,
+			   end_address);
+		if (my_edata >= (char *)start_address && my_edata < (char *)end_address) {
+			/* data section */
+			ret = lseek(fd, (long)(exe_header->section_header[i].s_scnptr), SEEK_SET);
+			assert(ret != -1);
+			ret = write(fd, (char *)start_address, my_edata - (char *)start_address);
+			assert(ret == my_edata - (char *)start_address);
+			++found_data;
+			printf("         .data, mem start 0x%08x mem length %d\n",
+				   start_address,
+				   my_edata - (char *)start_address);
+			printf("         .data, file start %d file length %d\n",
+				   (int)exe_header->section_header[i].s_scnptr,
+				   (int)exe_header->section_header[i].s_paddr);
+		} else if (my_endbss >= (char *)start_address && my_endbss < (char *)end_address) {
+			/* bss section */
+			++found_bss;
+			if (exe_header->section_header[i].s_flags & 0x00000080) {
+				/* convert uninitialized data section to initialized data section */
+				struct stat statbuf;
+				ret = fstat(fd, &statbuf);
+				assert(ret != -1);
+
+				exe_header->section_header[i].s_flags &= ~0x00000080;
+				exe_header->section_header[i].s_flags |= 0x00000040;
+
+				exe_header->section_header[i].s_scnptr =
+					(statbuf.st_size +
+					 exe_header->file_optional_header.FileAlignment) /
+					exe_header->file_optional_header.FileAlignment *
+					exe_header->file_optional_header.FileAlignment;
+
+				exe_header->section_header[i].s_size =
+					(exe_header->section_header[i].s_paddr +
+					 exe_header->file_optional_header.FileAlignment) /
+					exe_header->file_optional_header.FileAlignment *
+					exe_header->file_optional_header.FileAlignment;
+
+				ret = lseek(fd, (long)(exe_header->section_header[i].s_scnptr +
+									   exe_header->section_header[i].s_size - 1), SEEK_SET);
+				assert(ret != -1);
+				ret = write(fd, "", 1);
+				assert(ret == 1);
+
+				ret = lseek(fd, (long)((char *)&exe_header->section_header[i] - (char *)exe_header), SEEK_SET);
+				assert(ret != -1);
+				ret = write(fd, &exe_header->section_header[i], sizeof(exe_header->section_header[i]));
+				assert(ret == sizeof(exe_header->section_header[i]));
+				printf("         seek to %ld, write %d\n",
+					   (long)((char *)&exe_header->section_header[i] - (char *)exe_header),
+					   sizeof(exe_header->section_header[i]));
+			}
+			/* write initialized data section */
+			ret = lseek(fd, (long)(exe_header->section_header[i].s_scnptr), SEEK_SET);
+			assert(ret != -1);
+			ret = write(fd, (char *)start_address, my_endbss - (char *)start_address);
+			assert(ret == (my_endbss - (char *)start_address));
+			printf("         .bss, mem start 0x%08x mem length %d\n",
+				   start_address,
+				   my_endbss - (char *)start_address);
+			printf("         .bss, file start %d file length %d\n",
+				   (int)exe_header->section_header[i].s_scnptr,
+				   (int)exe_header->section_header[i].s_paddr);
+		}
+	}
+	assert(found_bss == 1);
+	assert(found_data == 1);
+}
+
+/*
+** Windows likes .exe suffixes on executables.
+*/
+static char *
+add_exe_suffix_if_necessary(const char *name, char *modified)
+{
+	int i = strlen(name);
+	if (i <= (sizeof(DOTEXE) - 1)) {
+		sprintf(modified, "%s%s", name, DOTEXE);
+	} else if (!strcmp(name + i - (sizeof(DOTEXE) - 1), DOTEXE)) {
+		strcpy(modified, name);
+	} else {
+		sprintf(modified, "%s%s", name, DOTEXE);
+	}
+	return(modified);
+}
+
+int
+unexec(char *outfile, char *infile, unsigned start_data, unsigned d1, unsigned d2)
+{
+	char infile_buffer[FILENAME_MAX];
+	char outfile_buffer[FILENAME_MAX];
+	int fd_in;
+	int fd_out;
+	int ret;
+	int ret2;
+
+	if (bss_sbrk_did_unexec) {
+		/* can only dump once */
+		printf("You can only dump emacs once on this platform.\n");
+		return(1);
+	}
+
+	report_sheap_usage(1);
+
+	infile = add_exe_suffix_if_necessary(infile, infile_buffer);
+	outfile = add_exe_suffix_if_necessary(outfile, outfile_buffer);
+
+	fd_in = open(infile, O_RDONLY | O_BINARY);
+	assert(fd_in >= 0);
+	fd_out = open(outfile, O_RDWR | O_TRUNC | O_CREAT | O_BINARY, 0755);
+	assert(fd_out >= 0);
+	for (;;) {
+		char buffer[4096];
+		ret = read(fd_in, buffer, sizeof(buffer));
+		if (ret == 0) {
+			/* eof */
+			break;
+		}
+		assert(ret > 0);
+		/* data */
+		ret2 = write(fd_out, buffer, ret);
+		assert(ret2 == ret);
+	}
+	ret = close(fd_in);
+	assert(ret == 0);
+
+	bss_sbrk_did_unexec = 1;
+	fixup_executable(fd_out);
+	bss_sbrk_did_unexec = 0;
+
+	ret = close(fd_out);
+	assert(ret == 0);
+
+	return(0);
+}

Re: [PATCH] unexec() for Cygwin port

[Eli Zaretskii]

> From: Joe Buehler <jbuehler@hekimian.com>
> Date: Mon, 29 Mar 2004 08:38:26 -0500
> 
> Below is a final set of patches to complete the Cygwin port for 21.3.50
> that I did about a year ago.  These patches add unexec() support for
> Cygwin, which is currently missing in CVS.

Thanks!

> Please commit it to CVS as soon as possible...

I have several minor comments:

> -mallocobj = $(gmallocobj) $(rallocobj) vm-limit.o
> -
>   #endif /* SYSTEM_MALLOC */
> 
> 
> @@ -643,7 +645,11 @@
> 
>   /* define otherobj as list of object files that make-docfile
>      should not be told about.  */
> -otherobj= $(termcapobj) lastfile.o $(mallocobj) $(allocaobj) $(widgetobj) $(LIBOBJS)
> +#ifdef CYGWIN
> +otherobj= $(termcapobj) $(gmallocobj) $(rallocobj) lastfile.o vm-limit.o $(allocaobj) $(widgetobj) $(LIBOBJS)
> +#else
> +otherobj= $(termcapobj) lastfile.o $(gmallocobj) $(rallocobj) vm-limit.o $(allocaobj) $(widgetobj) $(LIBOBJS)
> +#endif

Can you explain the need for this change, and n particular, why is it
important to order *.o files differently for Cygwin?

> +#if defined(CYGWIN)
> +  if (!bss_sbrk_did_unexec) {
> +    return bss_sbrk(increment);
> +  }
> +#endif

Here and elsewhere in your changes, you use code style that is
different from what we use in Emacs and in general in the GNU project:

    if (!bss_sbrk_did_unexec)
      {
        return bss_sbrk(increment);
      } 

Also, the code has lots of printf statements, most of which seem to be
left-overs from testing/debugging phase.  If so, they should be
removed or #ifdef'ed away, I think.

Btw, does unexcw.c handle correctly the debug info in temacs.exe,
i.e., is that info copied into emacs.exe so that Emacs could be
debugged?  (I'm asking because I don't see code that copies and
possibly fixes up the debug info sections.)

Re: [PATCH] unexec() for Cygwin port

[Joe Buehler]

Eli Zaretskii wrote:

>>-mallocobj = $(gmallocobj) $(rallocobj) vm-limit.o
>>-
>>  #endif /* SYSTEM_MALLOC */
>>
>>
>>@@ -643,7 +645,11 @@
>>
>>  /* define otherobj as list of object files that make-docfile
>>     should not be told about.  */
>>-otherobj= $(termcapobj) lastfile.o $(mallocobj) $(allocaobj) $(widgetobj) $(LIBOBJS)
>>+#ifdef CYGWIN
>>+otherobj= $(termcapobj) $(gmallocobj) $(rallocobj) lastfile.o vm-limit.o $(allocaobj) $(widgetobj) $(LIBOBJS)
>>+#else
>>+otherobj= $(termcapobj) lastfile.o $(gmallocobj) $(rallocobj) vm-limit.o $(allocaobj) $(widgetobj) $(LIBOBJS)
>>+#endif
> 
> 
> Can you explain the need for this change, and n particular, why is it
> important to order *.o files differently for Cygwin?

I believe it comes from the original xemacs code on which this was
modeled.  The Cygwin unexec() is a little different from typical
unexec() implementations in that the dumped executable does
not have segment boundaries adjusted or .data converted to .text
or anything of that sort.  The executable after the dump is identical
to what it was at the time of unexec().  So the state of the allocators
is saved by linking them before lastfile.o, which has the markers
for end of emacs .data/.bss.  The dumped emacs then comes up with
no knowledge that it has gone through an unexec()/exec() cycle.

>>+#if defined(CYGWIN)
>>+  if (!bss_sbrk_did_unexec) {
>>+    return bss_sbrk(increment);
>>+  }
>>+#endif
> 
> 
> Here and elsewhere in your changes, you use code style that is
> different from what we use in Emacs and in general in the GNU project:

I will look for the emacs GNU indent option since they are probably
documented somewhere, but if you have a pointer I would appreciate it.

> Also, the code has lots of printf statements, most of which seem to be
> left-overs from testing/debugging phase.  If so, they should be
> removed or #ifdef'ed away, I think.

Some of them are for error cases, which I definitely don't want to
change.

All of them only apply to undumping, which only happens during a
build.  I would like them to stay to help in solving any reported
problems.

> Btw, does unexcw.c handle correctly the debug info in temacs.exe,
> i.e., is that info copied into emacs.exe so that Emacs could be
> debugged?  (I'm asking because I don't see code that copies and
> possibly fixes up the debug info sections.)

It should.  All unexec() does for Cygwin is convert .bss into an
initialized data segment by changing some flags in the section
header and appending the data to the .exe file.  And rewrite the
appropriate part of .data, of course.
-- 
Joe Buehler

Re: [PATCH] unexec() for Cygwin port

[Stefan Monnier]

>> Also, the code has lots of printf statements, most of which seem to be
>> left-overs from testing/debugging phase.  If so, they should be
>> removed or #ifdef'ed away, I think.

> Some of them are for error cases, which I definitely don't want to
> change.

> All of them only apply to undumping, which only happens during a
> build.  I would like them to stay to help in solving any reported
> problems.

The macosx code also spits lots of "debug" output when dumping
and noone has complained about it.  I don't see any problem with that.
Especially during pretest.


        Stefan

Re: [PATCH] unexec() for Cygwin port

[Richard Stallman]

I see we already have papers for your Emacs changes, so if the people
who deal with Cygwin support like the patch, they can install it
immediately.

Re: [PATCH] unexec() for Cygwin port

[Eli Zaretskii]

> Date: Mon, 29 Mar 2004 15:38:34 -0500
> From: Joe Buehler <jbuehler@hekimian.com>
> > 
> > Here and elsewhere in your changes, you use code style that is
> > different from what we use in Emacs and in general in the GNU project:
> 
> I will look for the emacs GNU indent option since they are probably
> documented somewhere, but if you have a pointer I would appreciate it.

One place to look is in the node "Writing C" and its subnodes, in the
"GNU Coding Standards" manual.  It is available from the GNU FTP site:

   ftp://ftp.gnu.org/gnu/GNUinfo/standards.texi

Re: [PATCH] unexec() for Cygwin port

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: 29 Mar 2004 16:10:02 -0500
> 
> The macosx code also spits lots of "debug" output when dumping
> and noone has complained about it.  I don't see any problem with that.

I was under the impression that some printf's are really left-overs;
in particular, some of them there are in the normal execution path,
i.e. when there's no failure in sight.  Perhaps you should take a look
at the code yourself.

It is IMHO also advisable to figure out which of these printf's should
really be converted into calls to `abort', since in some grave cases,
a mere printf wouldn't give enough info to debug the problem.

> Especially during pretest.

What pretest?

Re: [PATCH] unexec() for Cygwin port

[Eli Zaretskii]

Btw, the function reproduced below should use a case-insensitive
comparison to the ".exe" string, as I'm sure you didn't mean that the
dumping should fail when some weirdo shell or Make hands you a name
like "EMACS.EXE" instead of the expected "emacs.exe".

+static char *
+add_exe_suffix_if_necessary(const char *name, char *modified)
+{
+	int i = strlen(name);
+	if (i <= (sizeof(DOTEXE) - 1)) {
+		sprintf(modified, "%s%s", name, DOTEXE);
+	} else if (!strcmp(name + i - (sizeof(DOTEXE) - 1), DOTEXE)) {
+		strcpy(modified, name);
+	} else {
+		sprintf(modified, "%s%s", name, DOTEXE);
+	}
+	return(modified);
+}

What Pretest? (was Re: [PATCH] unexec() for Cygwin port)

[Kim F. Storm]

Eli Zaretskii <eliz@elta.co.il> writes:

> > Especially during pretest.
> 
> What pretest?

That was a really good question !!!

It just occurred to me that with the free access to get, build, and use
CVS emacs, we are really in a constant "pretest" phase.

You can also judge that from the number of bug reports we get on
emacs-pretest-bug...

On the positive side of this, I would suppose that once we officially
enter pretest on 22.1, we will not need to go that many rounds before
we can do the actual release.

BTW, was is decided that we should update the version number of CVS
emacs to 22.0.50 ?  (or more radically switch to the new minor
numbering scheme that we discussed more than a year ago).

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk