[PATCH] unexec() for Cygwin port

[Joe Buehler <jbuehler@hekimian.com>]

[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);
+}