path: root/src/unexmips.c

/* Unexec for MIPS (including IRIS4D).
   Note that the GNU project considers support for MIPS operation
   a peripheral activity which should not be allowed to divert effort
   from development of the GNU system.  Changes in this code will be
   installed when users send them in, but aside from that
   we don't plan to think about it, or about whether other Emacs
   maintenance might break it.

   Copyright (C) 1988, 1994, 2001, 2002, 2003, 2004,
                 2005, 2006, 2007  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, 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., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */


#include <config.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <stdio.h>
#include <varargs.h>

#ifdef MACH

#include <a.out.h>

/* I don't know why this isn't defined.  */
#ifndef STYP_INIT
#define STYP_INIT  0x80000000
#endif

/* I don't know why this isn't defined.  */
#ifndef _RDATA
#define	_RDATA	".rdata"
#define STYP_RDATA 0x00000100
#endif

/* Small ("near") data section.  */
#ifndef _SDATA
#define	_SDATA	".sdata"
#define STYP_SDATA 0x00000200
#endif

/* Small ("near") bss section.  */
#ifndef _SBSS
#define _SBSS ".sbss"
#define STYP_SBSS 0x00000400
#endif

/* We don't seem to have a sym.h or syms.h anywhere, so we'll do it the
   hard way.  This stinks.  */
typedef struct {
  short   magic;
  short   vstamp;
  long    ilineMax;
  struct { long foo, offset; } offsets[11];
} HDRR, *pHDRR;

#else /* not MACH */

#include <filehdr.h>
#include <aouthdr.h>
#include <scnhdr.h>
#include <sym.h>

#endif /* not MACH */

#if defined (IRIS_4D) || defined (sony)
#include "getpagesize.h"
#include <fcntl.h>
#endif

static void fatal_unexec ();
static void mark_x ();

#define READ(_fd, _buffer, _size, _error_message, _error_arg) \
	errno = EEOF; \
	if (read (_fd, _buffer, _size) != _size) \
	  fatal_unexec (_error_message, _error_arg);

#define WRITE(_fd, _buffer, _size, _error_message, _error_arg) \
	if (write (_fd, _buffer, _size) != _size) \
	  fatal_unexec (_error_message, _error_arg);

#define SEEK(_fd, _position, _error_message, _error_arg) \
	errno = EEOF; \
	if (lseek (_fd, _position, L_SET) != _position) \
	  fatal_unexec (_error_message, _error_arg);

extern int errno;
extern char *strerror ();
#define EEOF -1

static struct scnhdr *text_section;
static struct scnhdr *init_section;
static struct scnhdr *finit_section;
static struct scnhdr *rdata_section;
static struct scnhdr *data_section;
static struct scnhdr *lit8_section;
static struct scnhdr *lit4_section;
static struct scnhdr *sdata_section;
static struct scnhdr *sbss_section;
static struct scnhdr *bss_section;

struct headers {
    struct filehdr fhdr;
    struct aouthdr aout;
    struct scnhdr section[10];
};

/* Define name of label for entry point for the dumped executable.  */

#ifndef DEFAULT_ENTRY_ADDRESS
#define DEFAULT_ENTRY_ADDRESS __start
#endif

unexec (new_name, a_name, data_start, bss_start, entry_address)
     char *new_name, *a_name;
     unsigned data_start, bss_start, entry_address;
{
  int new, old;
  int pagesize, brk;
  int newsyms, symrel;
  int nread;
  struct headers hdr;
  int i;
  int vaddr, scnptr;
#define BUFSIZE 8192
  char buffer[BUFSIZE];

  old = open (a_name, O_RDONLY, 0);
  if (old < 0) fatal_unexec ("opening %s", a_name);

  new = creat (new_name, 0666);
  if (new < 0) fatal_unexec ("creating %s", new_name);

  hdr = *((struct headers *)TEXT_START);
#ifdef MIPS2
  if (hdr.fhdr.f_magic != MIPSELMAGIC
      && hdr.fhdr.f_magic != MIPSEBMAGIC
      && hdr.fhdr.f_magic != (MIPSELMAGIC | 1)
      && hdr.fhdr.f_magic != (MIPSEBMAGIC | 1))
    {
      fprintf (stderr,
	       "unexec: input file magic number is %x, not %x, %x, %x or %x.\n",
	       hdr.fhdr.f_magic,
	       MIPSELMAGIC, MIPSEBMAGIC,
	       MIPSELMAGIC | 1, MIPSEBMAGIC | 1);
      exit(1);
    }
#else /* not MIPS2 */
  if (hdr.fhdr.f_magic != MIPSELMAGIC
      && hdr.fhdr.f_magic != MIPSEBMAGIC)
    {
      fprintf (stderr, "unexec: input file magic number is %x, not %x or %x.\n",
	       hdr.fhdr.f_magic, MIPSELMAGIC, MIPSEBMAGIC);
      exit (1);
    }
#endif /* not MIPS2 */
  if (hdr.fhdr.f_opthdr != sizeof (hdr.aout))
    {
      fprintf (stderr, "unexec: input a.out header is %d bytes, not %d.\n",
	       hdr.fhdr.f_opthdr, sizeof (hdr.aout));
      exit (1);
    }
  if (hdr.aout.magic != ZMAGIC)
    {
      fprintf (stderr, "unexec: input file a.out magic number is %o, not %o.\n",
	       hdr.aout.magic, ZMAGIC);
      exit (1);
    }

#define CHECK_SCNHDR(ptr, name, flags)					\
  ptr = NULL;								\
  for (i = 0; i < hdr.fhdr.f_nscns && !ptr; i++)			\
    if (strcmp (hdr.section[i].s_name, name) == 0)			\
      {									\
	if (hdr.section[i].s_flags != flags)				\
	  fprintf (stderr, "unexec: %x flags (%x expected) in %s section.\n", \
		   hdr.section[i].s_flags, flags, name);		\
	ptr = hdr.section + i;						\
      }									\

  CHECK_SCNHDR (text_section,  _TEXT,  STYP_TEXT);
  CHECK_SCNHDR (init_section,  _INIT,  STYP_INIT);
  CHECK_SCNHDR (rdata_section, _RDATA, STYP_RDATA);
  CHECK_SCNHDR (data_section,  _DATA,  STYP_DATA);
#ifdef _LIT8
  CHECK_SCNHDR (lit8_section,  _LIT8,  STYP_LIT8);
  CHECK_SCNHDR (lit4_section,  _LIT4,  STYP_LIT4);
#endif /* _LIT8 */
  CHECK_SCNHDR (sdata_section, _SDATA, STYP_SDATA);
  CHECK_SCNHDR (sbss_section,  _SBSS,  STYP_SBSS);
  CHECK_SCNHDR (bss_section,   _BSS,   STYP_BSS);
#if 0 /* Apparently this error check goes off on irix 3.3,
	 but it doesn't indicate a real problem.  */
  if (i != hdr.fhdr.f_nscns)
    fprintf (stderr, "unexec: %d sections found instead of %d.\n",
	     i, hdr.fhdr.f_nscns);
#endif

  text_section->s_scnptr = 0;

  pagesize = getpagesize ();
  /* Casting to int avoids compiler error on NEWS-OS 5.0.2.  */
  brk = (((int) (sbrk (0))) + pagesize - 1) & (-pagesize);
  hdr.aout.dsize = brk - DATA_START;
  hdr.aout.bsize = 0;
  if (entry_address == 0)
    {
      extern DEFAULT_ENTRY_ADDRESS ();
      hdr.aout.entry = (unsigned)DEFAULT_ENTRY_ADDRESS;
    }
  else
    hdr.aout.entry = entry_address;

  hdr.aout.bss_start = hdr.aout.data_start + hdr.aout.dsize;
  rdata_section->s_size = data_start - DATA_START;

  /* Adjust start and virtual addresses of rdata_section, too.  */
  rdata_section->s_vaddr = DATA_START;
  rdata_section->s_paddr = DATA_START;
  rdata_section->s_scnptr = text_section->s_scnptr + hdr.aout.tsize;

  data_section->s_vaddr = data_start;
  data_section->s_paddr = data_start;
  data_section->s_size = brk - data_start;
  data_section->s_scnptr = rdata_section->s_scnptr + rdata_section->s_size;
  vaddr = data_section->s_vaddr + data_section->s_size;
  scnptr = data_section->s_scnptr + data_section->s_size;
  if (lit8_section != NULL)
    {
      lit8_section->s_vaddr = vaddr;
      lit8_section->s_paddr = vaddr;
      lit8_section->s_size = 0;
      lit8_section->s_scnptr = scnptr;
    }
  if (lit4_section != NULL)
    {
      lit4_section->s_vaddr = vaddr;
      lit4_section->s_paddr = vaddr;
      lit4_section->s_size = 0;
      lit4_section->s_scnptr = scnptr;
    }
  if (sdata_section != NULL)
    {
      sdata_section->s_vaddr = vaddr;
      sdata_section->s_paddr = vaddr;
      sdata_section->s_size = 0;
      sdata_section->s_scnptr = scnptr;
    }
  if (sbss_section != NULL)
    {
      sbss_section->s_vaddr = vaddr;
      sbss_section->s_paddr = vaddr;
      sbss_section->s_size = 0;
      sbss_section->s_scnptr = scnptr;
    }
  if (bss_section != NULL)
    {
      bss_section->s_vaddr = vaddr;
      bss_section->s_paddr = vaddr;
      bss_section->s_size = 0;
      bss_section->s_scnptr = scnptr;
    }

  WRITE (new, (char *)TEXT_START, hdr.aout.tsize,
	 "writing text section to %s", new_name);
  WRITE (new, (char *)DATA_START, hdr.aout.dsize,
	 "writing data section to %s", new_name);

  SEEK (old, hdr.fhdr.f_symptr, "seeking to start of symbols in %s", a_name);
  errno = EEOF;
  nread = read (old, buffer, BUFSIZE);
  if (nread < sizeof (HDRR)) fatal_unexec ("reading symbols from %s", a_name);
  newsyms = hdr.aout.tsize + hdr.aout.dsize;
  symrel = newsyms - hdr.fhdr.f_symptr;
  hdr.fhdr.f_symptr = newsyms;
#define symhdr ((pHDRR)buffer)
#ifdef MACH
  for (i = 0; i < 11; i++)
    symhdr->offsets[i].offset += symrel;
#else
  symhdr->cbLineOffset += symrel;
  symhdr->cbDnOffset += symrel;
  symhdr->cbPdOffset += symrel;
  symhdr->cbSymOffset += symrel;
  symhdr->cbOptOffset += symrel;
  symhdr->cbAuxOffset += symrel;
  symhdr->cbSsOffset += symrel;
  symhdr->cbSsExtOffset += symrel;
  symhdr->cbFdOffset += symrel;
  symhdr->cbRfdOffset += symrel;
  symhdr->cbExtOffset += symrel;
#endif
#undef symhdr
  do
    {
      if (write (new, buffer, nread) != nread)
	fatal_unexec ("writing symbols to %s", new_name);
      nread = read (old, buffer, BUFSIZE);
      if (nread < 0) fatal_unexec ("reading symbols from %s", a_name);
#undef BUFSIZE
    } while (nread != 0);

  SEEK (new, 0, "seeking to start of header in %s", new_name);
  WRITE (new, &hdr, sizeof (hdr),
	 "writing header of %s", new_name);

  close (old);
  close (new);
  mark_x (new_name);
}

/*
 * mark_x
 *
 * After successfully building the new a.out, mark it executable
 */

static void
mark_x (name)
     char *name;
{
  struct stat sbuf;
  int um = umask (777);
  umask (um);
  if (stat (name, &sbuf) < 0)
    fatal_unexec ("getting protection on %s", name);
  sbuf.st_mode |= 0111 & ~um;
  if (chmod (name, sbuf.st_mode) < 0)
    fatal_unexec ("setting protection on %s", name);
}

static void
fatal_unexec (s, va_alist)
    va_dcl
{
  va_list ap;
  if (errno == EEOF)
    fputs ("unexec: unexpected end of file, ", stderr);
  else
    fprintf (stderr, "unexec: %s, ", strerror (errno));
  va_start (ap);
  _doprnt (s, ap, stderr);
  fputs (".\n", stderr);
  exit (1);
}

/* arch-tag: ebdd2058-3bbc-4de4-b5c7-5760379ab153
   (do not change this comment) */