[bpt/emacs.git] / src / unexcw.c

/* unexec() support for Cygwin;
   complete rewrite of xemacs Cygwin unexec() code

   Copyright (C) 2004-2012 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>
#include "unexec.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;

extern int __malloc_initialized;

/* 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;

int debug_unexcw = 0;

/*
** 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;
      if (debug_unexcw)
	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;
	  if (debug_unexcw)
	    printf ("         .data, mem start 0x%08x mem length %d\n",
		    start_address, my_edata - (char *) start_address);
	  if (debug_unexcw)
	    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]));
	      if (debug_unexcw)
		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);
	  /* force the dumped emacs to reinitialize malloc */
	  __malloc_initialized = 0;
	  ret =
	    write (fd, (char *) start_address,
		   my_endbss - (char *) start_address);
	  __malloc_initialized = 1;
	  assert (ret == (my_endbss - (char *) start_address));
	  if (debug_unexcw)
	    printf ("         .bss, mem start 0x%08x mem length %d\n",
		    start_address, my_endbss - (char *) start_address);
	  if (debug_unexcw)
	    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 (!strcasecmp (name + i - (sizeof (DOTEXE) - 1), DOTEXE))
    {
      strcpy (modified, name);
    }
  else
    {
      sprintf (modified, "%s%s", name, DOTEXE);
    }
  return (modified);
}

void
unexec (const char *outfile, const char *infile)
{
  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;
    }

  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);
}
Commit	Line	Data
3e62da95 SM	1	/* unexec() support for Cygwin;
	2	complete rewrite of xemacs Cygwin unexec() code
	3
acaf905b	4	Copyright (C) 2004-2012 Free Software Foundation, Inc.
3e62da95 SM	5
	6	This file is part of GNU Emacs.
	7
9ec0b715	8	GNU Emacs is free software: you can redistribute it and/or modify
3e62da95	9	it under the terms of the GNU General Public License as published by
9ec0b715 GM	10	the Free Software Foundation, either version 3 of the License, or
9ec0b715 GM	11	(at your option) any later version.
3e62da95 SM	12
	13	GNU Emacs is distributed in the hope that it will be useful,
	14	but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	GNU General Public License for more details.
	17
	18	You should have received a copy of the GNU General Public License
9ec0b715	19	along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
3e62da95 SM	20
3e62da95 SM	21	#include <config.h>
ce701a33 PE	22	#include "unexec.h"
ce701a33 PE	23
3e62da95 SM	24	#include <lisp.h>
	25	#include <stdio.h>
	26	#include <fcntl.h>
	27	#include <a.out.h>
	28	#include <unistd.h>
	29	#include <assert.h>
	30
	31	#define DOTEXE ".exe"
	32
	33	extern int bss_sbrk_did_unexec;
	34
a4579d33 KB	35	extern int __malloc_initialized;
a4579d33 KB	36
3e62da95 SM	37	/* emacs symbols that indicate where bss and data end for emacs internals */
	38	extern char my_endbss[];
	39	extern char my_edata[];
	40
	41	/*
	42	** header for Windows executable files
	43	*/
	44	typedef struct
	45	{
	46	FILHDR file_header;
	47	PEAOUTHDR file_optional_header;
	48	SCNHDR section_header[32];
	49	} exe_header_t;
	50
	51	int debug_unexcw = 0;
	52
	53	/*
	54	** Read the header from the executable into memory so we can more easily access it.
	55	*/
	56	static exe_header_t *
	57	read_exe_header (int fd, exe_header_t * exe_header_buffer)
	58	{
	59	int i;
	60	int ret;
	61
	62	assert (fd >= 0);
	63	assert (exe_header_buffer != 0);
	64
	65	ret = lseek (fd, 0L, SEEK_SET);
	66	assert (ret != -1);
	67
	68	ret =
	69	read (fd, &exe_header_buffer->file_header,
	70	sizeof (exe_header_buffer->file_header));
	71	assert (ret == sizeof (exe_header_buffer->file_header));
	72
	73	assert (exe_header_buffer->file_header.e_magic == 0x5a4d);
	74	assert (exe_header_buffer->file_header.nt_signature == 0x4550);
	75	assert (exe_header_buffer->file_header.f_magic == 0x014c);
	76	assert (exe_header_buffer->file_header.f_nscns > 0);
	77	assert (exe_header_buffer->file_header.f_nscns <=
	78	sizeof (exe_header_buffer->section_header) /
	79	sizeof (exe_header_buffer->section_header[0]));
	80	assert (exe_header_buffer->file_header.f_opthdr > 0);
	81
	82	ret =
	83	read (fd, &exe_header_buffer->file_optional_header,
	84	sizeof (exe_header_buffer->file_optional_header));
	85	assert (ret == sizeof (exe_header_buffer->file_optional_header));
	86
	87	assert (exe_header_buffer->file_optional_header.magic == 0x010b);
	88
	89	for (i = 0; i < exe_header_buffer->file_header.f_nscns; ++i)
	90	{
	91	ret =
	92	read (fd, &exe_header_buffer->section_header[i],
	93	sizeof (exe_header_buffer->section_header[i]));
	94	assert (ret == sizeof (exe_header_buffer->section_header[i]));
	95	}
	96
	97	return (exe_header_buffer);
	98	}
	99
	100	/*
101	** Fix the dumped emacs executable:
102	**
103	** - copy .data section data of interest from running executable into
104	** output .exe file
105	**
106	** - convert .bss section into an initialized data section (like
107	** .data) and copy .bss section data of interest from running
108	** executable into output .exe file
109	*/
110	static void
111	fixup_executable (int fd)
112	{
113	exe_header_t exe_header_buffer;
114	exe_header_t *exe_header;
115	int i;
116	int ret;
117	int found_data = 0;
118	int found_bss = 0;
119
120	exe_header = read_exe_header (fd, &exe_header_buffer);
121	assert (exe_header != 0);
122
123	assert (exe_header->file_header.f_nscns > 0);
124	for (i = 0; i < exe_header->file_header.f_nscns; ++i)
125	{
126	unsigned long start_address =
127	exe_header->section_header[i].s_vaddr +
128	exe_header->file_optional_header.ImageBase;
129	unsigned long end_address =
130	exe_header->section_header[i].s_vaddr +
131	exe_header->file_optional_header.ImageBase +
132	exe_header->section_header[i].s_paddr;
133	if (debug_unexcw)
134	printf ("%8s start 0x%08x end 0x%08x\n",
135	exe_header->section_header[i].s_name,
136	start_address, end_address);
137	if (my_edata >= (char *) start_address
138	&& my_edata < (char *) end_address)
139	{
140	/* data section */
141	ret =
142	lseek (fd, (long) (exe_header->section_header[i].s_scnptr),
143	SEEK_SET);
144	assert (ret != -1);
145	ret =
146	write (fd, (char *) start_address,
147	my_edata - (char *) start_address);
148	assert (ret == my_edata - (char *) start_address);
149	++found_data;
150	if (debug_unexcw)
151	printf (" .data, mem start 0x%08x mem length %d\n",
152	start_address, my_edata - (char *) start_address);
153	if (debug_unexcw)
154	printf (" .data, file start %d file length %d\n",
155	(int) exe_header->section_header[i].s_scnptr,
156	(int) exe_header->section_header[i].s_paddr);
157	}
158	else if (my_endbss >= (char *) start_address
159	&& my_endbss < (char *) end_address)
160	{
161	/* bss section */
162	++found_bss;
163	if (exe_header->section_header[i].s_flags & 0x00000080)
164	{
165	/* convert uninitialized data section to initialized data section */
166	struct stat statbuf;
167	ret = fstat (fd, &statbuf);
168	assert (ret != -1);
169
170	exe_header->section_header[i].s_flags &= ~0x00000080;
171	exe_header->section_header[i].s_flags \|= 0x00000040;
172
173	exe_header->section_header[i].s_scnptr =
174	(statbuf.st_size +
175	exe_header->file_optional_header.FileAlignment) /
176	exe_header->file_optional_header.FileAlignment *
177	exe_header->file_optional_header.FileAlignment;
178
179	exe_header->section_header[i].s_size =
180	(exe_header->section_header[i].s_paddr +
181	exe_header->file_optional_header.FileAlignment) /
182	exe_header->file_optional_header.FileAlignment *
183	exe_header->file_optional_header.FileAlignment;
184
185	ret =
186	lseek (fd,
187	(long) (exe_header->section_header[i].s_scnptr +
188	exe_header->section_header[i].s_size - 1),
189	SEEK_SET);
190	assert (ret != -1);
191	ret = write (fd, "", 1);
192	assert (ret == 1);
193
194	ret =
195	lseek (fd,
196	(long) ((char *) &exe_header->section_header[i] -
197	(char *) exe_header), SEEK_SET);
198	assert (ret != -1);
199	ret =
200	write (fd, &exe_header->section_header[i],
201	sizeof (exe_header->section_header[i]));
202	assert (ret == sizeof (exe_header->section_header[i]));
203	if (debug_unexcw)
204	printf (" seek to %ld, write %d\n",
205	(long) ((char *) &exe_header->section_header[i] -
206	(char *) exe_header),
207	sizeof (exe_header->section_header[i]));
208	}
209	/* write initialized data section */
210	ret =
211	lseek (fd, (long) (exe_header->section_header[i].s_scnptr),
212	SEEK_SET);
213	assert (ret != -1);
a4579d33 KB	214	/* force the dumped emacs to reinitialize malloc */
a4579d33 KB	215	__malloc_initialized = 0;
3e62da95 SM	216	ret =
	217	write (fd, (char *) start_address,
	218	my_endbss - (char *) start_address);
a4579d33	219	__malloc_initialized = 1;
3e62da95 SM	220	assert (ret == (my_endbss - (char *) start_address));
	221	if (debug_unexcw)
	222	printf (" .bss, mem start 0x%08x mem length %d\n",
	223	start_address, my_endbss - (char *) start_address);
	224	if (debug_unexcw)
	225	printf (" .bss, file start %d file length %d\n",
	226	(int) exe_header->section_header[i].s_scnptr,
	227	(int) exe_header->section_header[i].s_paddr);
	228	}
	229	}
	230	assert (found_bss == 1);
	231	assert (found_data == 1);
	232	}
	233
	234	/*
	235	** Windows likes .exe suffixes on executables.
	236	*/
	237	static char *
	238	add_exe_suffix_if_necessary (const char name, char modified)
	239	{
	240	int i = strlen (name);
	241	if (i <= (sizeof (DOTEXE) - 1))
	242	{
	243	sprintf (modified, "%s%s", name, DOTEXE);
	244	}
	245	else if (!strcasecmp (name + i - (sizeof (DOTEXE) - 1), DOTEXE))
	246	{
	247	strcpy (modified, name);
	248	}
	249	else
	250	{
	251	sprintf (modified, "%s%s", name, DOTEXE);
	252	}
	253	return (modified);
	254	}
	255
381259ef	256	void
dd5ecd6b	257	unexec (const char outfile, const char infile)
3e62da95 SM	258	{
	259	char infile_buffer[FILENAME_MAX];
	260	char outfile_buffer[FILENAME_MAX];
	261	int fd_in;
	262	int fd_out;
	263	int ret;
	264	int ret2;
	265
	266	if (bss_sbrk_did_unexec)
	267	{
	268	/* can only dump once */
60a294e2	269	printf ("You can only dump Emacs once on this platform.\n");
fffe2e14	270	return;
3e62da95 SM	271	}
	272
	273	report_sheap_usage (1);
	274
	275	infile = add_exe_suffix_if_necessary (infile, infile_buffer);
	276	outfile = add_exe_suffix_if_necessary (outfile, outfile_buffer);
	277
	278	fd_in = open (infile, O_RDONLY \| O_BINARY);
	279	assert (fd_in >= 0);
	280	fd_out = open (outfile, O_RDWR \| O_TRUNC \| O_CREAT \| O_BINARY, 0755);
	281	assert (fd_out >= 0);
	282	for (;;)
	283	{
	284	char buffer[4096];
	285	ret = read (fd_in, buffer, sizeof (buffer));
	286	if (ret == 0)
	287	{
	288	/* eof */
	289	break;
	290	}
	291	assert (ret > 0);
	292	/* data */
	293	ret2 = write (fd_out, buffer, ret);
	294	assert (ret2 == ret);
	295	}
	296	ret = close (fd_in);
	297	assert (ret == 0);
	298
	299	bss_sbrk_did_unexec = 1;
	300	fixup_executable (fd_out);
	301	bss_sbrk_did_unexec = 0;
	302
	303	ret = close (fd_out);
	304	assert (ret == 0);
3e62da95	305	}