diff src/unexaix.c @ 0:376386a54a3c r19-14

Import from CVS: tag r19-14
author cvs
date Mon, 13 Aug 2007 08:45:50 +0200
parents
children e45d5e7c476e
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/unexaix.c	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,881 @@
+/* Copyright (C) 1985, 1986, 1987, 1988 Free Software Foundation, Inc.
+
+This file is part of XEmacs.
+
+XEmacs 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.
+
+XEmacs 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 XEmacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+/* Synched up with: FSF 19.31. */
+
+/* Modified by Andrew.Vignaux@comp.vuw.ac.nz to get it to work :-) */
+
+/*
+ * unexec.c - Convert a running program into an a.out file.
+ *
+ * Author:	Spencer W. Thomas
+ * 		Computer Science Dept.
+ * 		University of Utah
+ * Date:	Tue Mar  2 1982
+ * Modified heavily since then.
+ *
+ * Updated for AIX 4.1.3 by Bill_Mann @ PraxisInt.com, Feb 1996
+ *   As of AIX 4.1, text, data, and bss are pre-relocated by the binder in
+ *   such a way that the file can be mapped with code in one segment and
+ *   data/bss in another segment, without reading or copying the file, by
+ *   the AIX exec loader.  Padding sections are omitted, nevertheless
+ *   small amounts of 'padding' still occurs between sections in the file.
+ *   As modified, this code handles both 3.2 and 4.1 conventions.
+ *
+ * Synopsis:
+ *	unexec (new_name, a_name, data_start, bss_start, entry_address)
+ *	char *new_name, *a_name;
+ *	unsigned data_start, bss_start, entry_address;
+ *
+ * Takes a snapshot of the program and makes an a.out format file in the
+ * file named by the string argument new_name.
+ * If a_name is non-NULL, the symbol table will be taken from the given file.
+ * On some machines, an existing a_name file is required.
+ *
+ * The boundaries within the a.out file may be adjusted with the data_start
+ * and bss_start arguments.  Either or both may be given as 0 for defaults.
+ *
+ * Data_start gives the boundary between the text segment and the data
+ * segment of the program.  The text segment can contain shared, read-only
+ * program code and literal data, while the data segment is always unshared
+ * and unprotected.  Data_start gives the lowest unprotected address.
+ * The value you specify may be rounded down to a suitable boundary
+ * as required by the machine you are using.
+ *
+ * Specifying zero for data_start means the boundary between text and data
+ * should not be the same as when the program was loaded.
+ * If NO_REMAP is defined, the argument data_start is ignored and the
+ * segment boundaries are never changed.
+ *
+ * Bss_start indicates how much of the data segment is to be saved in the
+ * a.out file and restored when the program is executed.  It gives the lowest
+ * unsaved address, and is rounded up to a page boundary.  The default when 0
+ * is given assumes that the entire data segment is to be stored, including
+ * the previous data and bss as well as any additional storage allocated with
+ * break (2).
+ *
+ * The new file is set up to start at entry_address.
+ *
+ * If you make improvements I'd like to get them too.
+ * harpo!utah-cs!thomas, thomas@Utah-20
+ *
+ */
+
+/* There are several compilation parameters affecting unexec:
+
+* COFF
+
+Define this if your system uses COFF for executables.
+Otherwise we assume you use Berkeley format.
+
+* NO_REMAP
+
+Define this if you do not want to try to save Emacs's pure data areas
+as part of the text segment.
+
+Saving them as text is good because it allows users to share more.
+
+However, on machines that locate the text area far from the data area,
+the boundary cannot feasibly be moved.  Such machines require
+NO_REMAP.
+
+Also, remapping can cause trouble with the built-in startup routine
+/lib/crt0.o, which defines `environ' as an initialized variable.
+Dumping `environ' as pure does not work!  So, to use remapping,
+you must write a startup routine for your machine in Emacs's crt0.c.
+If NO_REMAP is defined, Emacs uses the system's crt0.o.
+
+* SECTION_ALIGNMENT
+
+Some machines that use COFF executables require that each section
+start on a certain boundary *in the COFF file*.  Such machines should
+define SECTION_ALIGNMENT to a mask of the low-order bits that must be
+zero on such a boundary.  This mask is used to control padding between
+segments in the COFF file.
+
+If SECTION_ALIGNMENT is not defined, the segments are written
+consecutively with no attempt at alignment.  This is right for
+unmodified system V.
+
+* SEGMENT_MASK
+
+Some machines require that the beginnings and ends of segments
+*in core* be on certain boundaries.  For most machines, a page
+boundary is sufficient.  That is the default.  When a larger
+boundary is needed, define SEGMENT_MASK to a mask of
+the bits that must be zero on such a boundary.
+
+* A_TEXT_OFFSET(HDR)
+
+Some machines count the a.out header as part of the size of the text
+segment (a_text); they may actually load the header into core as the
+first data in the text segment.  Some have additional padding between
+the header and the real text of the program that is counted in a_text.
+
+For these machines, define A_TEXT_OFFSET(HDR) to examine the header
+structure HDR and return the number of bytes to add to `a_text'
+before writing it (above and beyond the number of bytes of actual
+program text).  HDR's standard fields are already correct, except that
+this adjustment to the `a_text' field has not yet been made;
+thus, the amount of offset can depend on the data in the file.
+  
+* A_TEXT_SEEK(HDR)
+
+If defined, this macro specifies the number of bytes to seek into the
+a.out file before starting to write the text segment.a
+
+* EXEC_MAGIC
+
+For machines using COFF, this macro, if defined, is a value stored
+into the magic number field of the output file.
+
+* ADJUST_EXEC_HEADER
+
+This macro can be used to generate statements to adjust or
+initialize nonstandard fields in the file header
+
+* ADDR_CORRECT(ADDR)
+
+Macro to correct an int which is the bit pattern of a pointer to a byte
+into an int which is the number of a byte.
+
+This macro has a default definition which is usually right.
+This default definition is a no-op on most machines (where a
+pointer looks like an int) but not on all machines.
+
+*/
+
+#define XCOFF
+#define COFF
+#define NO_REMAP
+
+#ifndef emacs
+#define PERROR(arg) perror (arg); return -1
+#else
+#include <config.h>
+#define PERROR(file) report_error (file, new)
+#endif
+
+#include <a.out.h>
+/* Define getpagesize () if the system does not.
+   Note that this may depend on symbols defined in a.out.h
+ */
+#include "getpagesize.h"
+
+#ifndef makedev			/* Try to detect types.h already loaded */
+#include <sys/types.h>
+#endif
+#include <stdio.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+extern char *start_of_text ();		/* Start of text */
+extern char *start_of_data ();		/* Start of initialized data */
+
+extern int _data;
+extern int _edata;
+extern int _text;
+extern int _etext;
+extern int _end;
+#ifdef COFF
+#ifndef USG
+#ifndef STRIDE
+#ifndef UMAX
+#ifndef sun386
+/* I have a suspicion that these are turned off on all systems
+   and can be deleted.  Try it in version 19.  */
+#include <filehdr.h>
+#include <aouthdr.h>
+#include <scnhdr.h>
+#include <syms.h>
+#endif /* not sun386 */
+#endif /* not UMAX */
+#endif /* Not STRIDE */
+#endif /* not USG */
+static struct filehdr f_hdr;		/* File header */
+static struct aouthdr f_ohdr;		/* Optional file header (a.out) */
+long bias;			/* Bias to add for growth */
+long lnnoptr;			/* Pointer to line-number info within file */
+
+static long text_scnptr;
+static long data_scnptr;
+#ifdef XCOFF
+#define ALIGN(val, pwr) (((val) + ((1L<<(pwr))-1)) & ~((1L<<(pwr))-1))
+static long load_scnptr;
+static long orig_load_scnptr;
+static long orig_data_scnptr;
+#endif
+static ulong data_st;                   /* start of data area written out */
+
+#ifndef MAX_SECTIONS
+#define MAX_SECTIONS	10
+#endif
+
+#endif /* COFF */
+
+static int pagemask;
+
+/* Correct an int which is the bit pattern of a pointer to a byte
+   into an int which is the number of a byte.
+   This is a no-op on ordinary machines, but not on all.  */
+
+#ifndef ADDR_CORRECT   /* Let m-*.h files override this definition */
+#define ADDR_CORRECT(x) ((char *)(x) - (char*)0)
+#endif
+
+#ifdef emacs
+#include "lisp.h"
+
+static
+report_error (file, fd)
+     char *file;
+     int fd;
+{
+  if (fd)
+    close (fd);
+  report_file_error ("Cannot unexec", Fcons (build_string (file), Qnil));
+}
+#endif /* emacs */
+
+#define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1
+#define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1
+#define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1
+
+static
+report_error_1 (fd, msg, a1, a2)
+     int fd;
+     char *msg;
+     int a1, a2;
+{
+  close (fd);
+#ifdef emacs
+  error (msg, a1, a2);
+#else
+  fprintf (stderr, msg, a1, a2);
+  fprintf (stderr, "\n");
+#endif
+}
+
+static int make_hdr ();
+static void mark_x ();
+static int copy_text_and_data ();
+static int copy_sym ();
+
+/* ****************************************************************
+ * unexec
+ *
+ * driving logic.
+ */
+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, a_out = -1;
+
+  if (a_name && (a_out = open (a_name, 0)) < 0)
+    {
+      PERROR (a_name);
+    }
+  if ((new = creat (new_name, 0666)) < 0)
+    {
+      PERROR (new_name);
+    }
+  if (make_hdr (new,a_out,data_start,bss_start,entry_address,a_name,new_name) < 0
+      || copy_text_and_data (new) < 0
+      || copy_sym (new, a_out, a_name, new_name) < 0
+#ifdef COFF
+      || adjust_lnnoptrs (new, a_out, new_name) < 0
+#endif
+#ifdef XCOFF
+      || unrelocate_symbols (new, a_out, a_name, new_name) < 0
+#endif
+      )
+    {
+      close (new);
+      /* unlink (new_name);	    	/* Failed, unlink new a.out */
+      return -1;	
+    }
+
+  close (new);
+  if (a_out >= 0)
+    close (a_out);
+  mark_x (new_name);
+  return 0;
+}
+
+/* ****************************************************************
+ * make_hdr
+ *
+ * Make the header in the new a.out from the header in core.
+ * Modify the text and data sizes.
+ */
+static int
+make_hdr (new, a_out, data_start, bss_start, entry_address, a_name, new_name)
+     int new, a_out;
+     unsigned data_start, bss_start, entry_address;
+     char *a_name;
+     char *new_name;
+{
+  int scns;
+  unsigned int bss_end;
+
+  struct scnhdr section[MAX_SECTIONS];
+  struct scnhdr * f_thdr;		/* Text section header */
+  struct scnhdr * f_dhdr;		/* Data section header */
+  struct scnhdr * f_bhdr;		/* Bss section header */
+  struct scnhdr * f_lhdr;		/* Loader section header */
+  struct scnhdr * f_tchdr;		/* Typechk section header */
+  struct scnhdr * f_dbhdr;		/* Debug section header */
+  struct scnhdr * f_xhdr;		/* Except section header */
+
+  load_scnptr = orig_load_scnptr = lnnoptr = 0;
+  pagemask = getpagesize () - 1;
+
+  /* Adjust text/data boundary. */
+#ifdef NO_REMAP
+  data_start = (long) start_of_data ();
+#endif /*  NO_REMAP */
+  data_start = ADDR_CORRECT (data_start);
+
+#ifdef SEGMENT_MASK
+  data_start = data_start & ~SEGMENT_MASK; /* (Down) to segment boundary. */
+#else
+  data_start = data_start & ~pagemask; /* (Down) to page boundary. */
+#endif
+
+
+  bss_end = ADDR_CORRECT (sbrk (0)) + pagemask;
+  bss_end &= ~ pagemask;
+  /* Adjust data/bss boundary. */
+  if (bss_start != 0)
+    {
+      bss_start = (ADDR_CORRECT (bss_start) + pagemask);
+      /* (Up) to page bdry. */
+      bss_start &= ~ pagemask;
+      if (bss_start > bss_end)
+	{
+	  ERROR1 ("unexec: Specified bss_start (%u) is past end of program",
+		  bss_start);
+	}
+    }
+  else
+    bss_start = bss_end;
+
+  if (data_start > bss_start)	/* Can't have negative data size. */
+    {
+      ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)",
+	      data_start, bss_start);
+    }
+
+#ifdef COFF
+  /* Salvage as much info from the existing file as possible */
+  f_thdr = NULL; f_dhdr = NULL; f_bhdr = NULL;
+  f_lhdr = NULL; f_tchdr = NULL; f_dbhdr = NULL; f_xhdr = NULL;
+  if (a_out >= 0)
+    {
+      if (read (a_out, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
+	{
+	  PERROR (a_name);
+	}
+      if (f_hdr.f_opthdr > 0)
+	{
+	  if (read (a_out, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
+	    {
+	      PERROR (a_name);
+	    }
+	}
+      if (f_hdr.f_nscns > MAX_SECTIONS)
+	{
+	  ERROR0 ("unexec: too many section headers -- increase MAX_SECTIONS");
+	}
+      /* Loop through section headers */
+      for (scns = 0; scns < f_hdr.f_nscns; scns++) {
+	struct scnhdr *s = &section[scns];
+	if (read (a_out, s, sizeof (*s)) != sizeof (*s))
+	  {
+	    PERROR (a_name);
+	  }
+
+#define CHECK_SCNHDR(ptr, name, flags) \
+  if (strcmp(s->s_name, name) == 0) { \
+    if (s->s_flags != flags) { \
+      fprintf(stderr, "unexec: %lx flags where %x expected in %s section.\n", \
+	      (unsigned long)s->s_flags, flags, name); \
+    } \
+    if (ptr) { \
+      fprintf(stderr, "unexec: duplicate section header for section %s.\n", \
+	      name); \
+    } \
+    ptr = s; \
+  }
+	CHECK_SCNHDR(f_thdr, _TEXT, STYP_TEXT);
+	CHECK_SCNHDR(f_dhdr, _DATA, STYP_DATA);
+	CHECK_SCNHDR(f_bhdr, _BSS, STYP_BSS);
+	CHECK_SCNHDR(f_lhdr, _LOADER, STYP_LOADER);
+	CHECK_SCNHDR(f_dbhdr, _DEBUG,  STYP_DEBUG);
+	CHECK_SCNHDR(f_tchdr, _TYPCHK,  STYP_TYPCHK);
+	CHECK_SCNHDR(f_xhdr, _EXCEPT,  STYP_EXCEPT);
+      }
+
+      if (f_thdr == 0)
+	{
+	  ERROR1 ("unexec: couldn't find \"%s\" section", _TEXT);
+	}
+      if (f_dhdr == 0)
+	{
+	  ERROR1 ("unexec: couldn't find \"%s\" section", _DATA);
+	}
+      if (f_bhdr == 0)
+	{
+	  ERROR1 ("unexec: couldn't find \"%s\" section", _BSS);
+	}
+    }
+  else
+    {
+      ERROR0 ("can't build a COFF file from scratch yet");
+    }
+  orig_data_scnptr = f_dhdr->s_scnptr;
+  orig_load_scnptr = f_lhdr ? f_lhdr->s_scnptr : 0;
+
+  /* Now we alter the contents of all the f_*hdr variables
+     to correspond to what we want to dump.  */
+
+  /* Indicate that the reloc information is no longer valid for ld (bind);
+     we only update it enough to fake out the exec-time loader.  */
+  f_hdr.f_flags |= (F_RELFLG | F_EXEC);
+
+#ifdef EXEC_MAGIC
+  f_ohdr.magic = EXEC_MAGIC;
+#endif
+#ifndef NO_REMAP
+  f_ohdr.tsize = data_start - f_ohdr.text_start;
+  f_ohdr.text_start = (long) start_of_text ();
+#endif
+  data_st = f_ohdr.data_start ? f_ohdr.data_start : (ulong) &_data;
+  f_ohdr.dsize = bss_start - data_st;
+  f_ohdr.bsize = bss_end - bss_start;
+
+  f_dhdr->s_size = f_ohdr.dsize;
+  f_bhdr->s_size = f_ohdr.bsize;
+  f_bhdr->s_paddr = f_ohdr.data_start + f_ohdr.dsize;
+  f_bhdr->s_vaddr = f_ohdr.data_start + f_ohdr.dsize;
+
+  /* fix scnptr's */
+  {
+    ulong ptr = section[0].s_scnptr;
+
+    bias = -1;
+    for (scns = 0; scns < f_hdr.f_nscns; scns++)
+      {
+	struct scnhdr *s = &section[scns];
+
+	if (s->s_flags & STYP_PAD)        /* .pad sections omitted in AIX 4.1 */
+	  {
+	    /*
+	     * the text_start should probably be o_algntext but that doesn't
+	     * seem to change
+	     */
+	    if (f_ohdr.text_start != 0) /* && scns != 0 */
+	      {
+		s->s_size = 512 - (ptr % 512);
+		if (s->s_size == 512)
+		  s->s_size = 0;
+	      }
+	    s->s_scnptr = ptr;
+	  }
+	else if (s->s_flags & STYP_DATA)
+	  s->s_scnptr = ptr;
+	else if (!(s->s_flags & (STYP_TEXT | STYP_BSS)))
+	  {
+	    if (bias == -1)                /* if first section after bss */
+	      bias = ptr - s->s_scnptr;
+
+	    s->s_scnptr += bias;
+	    ptr = s->s_scnptr;
+	  }
+  
+	ptr = ptr + s->s_size;
+      }
+  }
+
+  /* fix other pointers */
+  for (scns = 0; scns < f_hdr.f_nscns; scns++)
+    {
+      struct scnhdr *s = &section[scns];
+
+      if (s->s_relptr != 0)
+	{
+	  s->s_relptr += bias;
+	}
+      if (s->s_lnnoptr != 0)
+	{
+	  if (lnnoptr == 0) lnnoptr = s->s_lnnoptr;
+	  s->s_lnnoptr += bias;
+	}
+    }
+
+  if (f_hdr.f_symptr > 0L)
+    {
+      f_hdr.f_symptr += bias;
+    }
+
+  text_scnptr = f_thdr->s_scnptr;
+  data_scnptr = f_dhdr->s_scnptr;
+  load_scnptr = f_lhdr ? f_lhdr->s_scnptr : 0;
+
+#ifdef ADJUST_EXEC_HEADER
+  ADJUST_EXEC_HEADER
+#endif /* ADJUST_EXEC_HEADER */
+
+  if (write (new, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
+    {
+      PERROR (new_name);
+    }
+
+  if (f_hdr.f_opthdr > 0)
+    {
+      if (write (new, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
+	{
+	  PERROR (new_name);
+	}
+    }
+
+  for (scns = 0; scns < f_hdr.f_nscns; scns++) {
+    struct scnhdr *s = &section[scns];
+    if (write (new, s, sizeof (*s)) != sizeof (*s))
+      {
+	PERROR (new_name);
+      }
+  }
+
+  return (0);
+
+#endif /* COFF */
+}
+
+/* ****************************************************************
+ 
+ *
+ * Copy the text and data segments from memory to the new a.out
+ */
+static int
+copy_text_and_data (new)
+     int new;
+{
+  char *end;
+  char *ptr;
+
+  lseek (new, (long) text_scnptr, 0);
+  ptr = start_of_text () + text_scnptr;
+  end = ptr + f_ohdr.tsize;
+  write_segment (new, ptr, end);
+
+  lseek (new, (long) data_scnptr, 0);
+  ptr = (char *) data_st;
+  end = ptr + f_ohdr.dsize;
+  write_segment (new, ptr, end);
+
+  return 0;
+}
+
+#define UnexBlockSz (1<<12)			/* read/write block size */
+write_segment (new, ptr, end)
+     int new;
+     char *ptr, *end;
+{
+  int i, nwrite, ret;
+  char buf[80];
+  extern int errno;
+  char zeros[UnexBlockSz];
+
+  for (i = 0; ptr < end;)
+    {
+      /* distance to next block.  */
+      nwrite = (((int) ptr + UnexBlockSz) & -UnexBlockSz) - (int) ptr;
+      /* But not beyond specified end.  */
+      if (nwrite > end - ptr) nwrite = end - ptr;
+      ret = write (new, ptr, nwrite);
+      /* If write gets a page fault, it means we reached
+	 a gap between the old text segment and the old data segment.
+	 This gap has probably been remapped into part of the text segment.
+	 So write zeros for it.  */
+      if (ret == -1 && errno == EFAULT)
+	{
+	  bzero (zeros, nwrite);
+	  write (new, zeros, nwrite);
+	}
+      else if (nwrite != ret)
+	{
+	  sprintf (buf,
+		   "unexec write failure: addr 0x%lx, fileno %d, size 0x%x, wrote 0x%x, errno %d",
+		   (unsigned long)ptr, new, nwrite, ret, errno);
+	  PERROR (buf);
+	}
+      i += nwrite;
+      ptr += nwrite;
+    }
+}
+
+/* ****************************************************************
+ * copy_sym
+ *
+ * Copy the relocation information and symbol table from the a.out to the new
+ */
+static int
+copy_sym (new, a_out, a_name, new_name)
+     int new, a_out;
+     char *a_name, *new_name;
+{
+  char page[UnexBlockSz];
+  int n;
+
+  if (a_out < 0)
+    return 0;
+
+  if (orig_load_scnptr == 0L)
+    return 0;
+
+  if (lnnoptr && lnnoptr < orig_load_scnptr) /* if there is line number info  */
+    lseek (a_out, lnnoptr, 0);  /* start copying from there */
+  else
+    lseek (a_out, orig_load_scnptr, 0); /* Position a.out to symtab. */
+
+  while ((n = read (a_out, page, sizeof page)) > 0)
+    {
+      if (write (new, page, n) != n)
+	{
+	  PERROR (new_name);
+	}
+    }
+  if (n < 0)
+    {
+      PERROR (a_name);
+    }
+  return 0;
+}
+
+/* ****************************************************************
+ * mark_x
+ *
+ * After successfully building the new a.out, mark it executable
+ */
+static void
+mark_x (name)
+     char *name;
+{
+  struct stat sbuf;
+  int um;
+  int new = 0;  /* for PERROR */
+
+  um = umask (777);
+  umask (um);
+  if (stat (name, &sbuf) == -1)
+    {
+      PERROR (name);
+    }
+  sbuf.st_mode |= 0111 & ~um;
+  if (chmod (name, sbuf.st_mode) == -1)
+    PERROR (name);
+}
+
+/*
+ *	If the COFF file contains a symbol table and a line number section,
+ *	then any auxiliary entries that have values for x_lnnoptr must
+ *	be adjusted by the amount that the line number section has moved
+ *	in the file (bias computed in make_hdr).  The #@$%&* designers of
+ *	the auxiliary entry structures used the absolute file offsets for
+ *	the line number entry rather than an offset from the start of the
+ *	line number section!
+ *
+ *	When I figure out how to scan through the symbol table and pick out
+ *	the auxiliary entries that need adjustment, this routine will
+ *	be fixed.  As it is now, all such entries are wrong and sdb
+ *	will complain.   Fred Fish, UniSoft Systems Inc.
+ *
+ *      I believe this is now fixed correctly.  Bill Mann
+ */
+
+#ifdef COFF
+
+/* This function is probably very slow.  Instead of reopening the new
+   file for input and output it should copy from the old to the new
+   using the two descriptors already open (WRITEDESC and READDESC).
+   Instead of reading one small structure at a time it should use
+   a reasonable size buffer.  But I don't have time to work on such
+   things, so I am installing it as submitted to me.  -- RMS.  */
+
+adjust_lnnoptrs (writedesc, readdesc, new_name)
+     int writedesc;
+     int readdesc;
+     char *new_name;
+{
+  int nsyms;
+  int naux;
+  int new;
+#ifdef amdahl_uts
+  SYMENT symentry;
+  AUXENT auxentry;
+#else
+  struct syment symentry;
+  union auxent auxentry;
+#endif
+
+  if (!lnnoptr || !f_hdr.f_symptr)
+    return 0;
+
+  if ((new = open (new_name, 2)) < 0)
+    {
+      PERROR (new_name);
+      return -1;
+    }
+
+  lseek (new, f_hdr.f_symptr, 0);
+  for (nsyms = 0; nsyms < f_hdr.f_nsyms; nsyms++)
+    {
+      read (new, &symentry, SYMESZ);
+      if (symentry.n_sclass == C_BINCL || symentry.n_sclass == C_EINCL)
+	{
+	  symentry.n_value += bias;
+	  lseek (new, -SYMESZ, 1);
+	  write (new, &symentry, SYMESZ);
+	}
+
+      for (naux = symentry.n_numaux; naux-- != 0; )
+	{
+	  read (new, &auxentry, AUXESZ);
+	  nsyms++;
+	  if (naux != 0              /* skip csect auxentry (last entry) */
+              && (symentry.n_sclass == C_EXT || symentry.n_sclass == C_HIDEXT))
+            {
+              auxentry.x_sym.x_fcnary.x_fcn.x_lnnoptr += bias;
+              lseek (new, -AUXESZ, 1);
+              write (new, &auxentry, AUXESZ);
+            }
+	}
+    }
+  close (new);
+}
+
+#endif /* COFF */
+
+#ifdef XCOFF
+
+/* It is probably a false economy to optimise this routine (it used to
+   read one LDREL and do do two lseeks per iteration) but the wrath of
+   RMS (see above :-) would be too much to bear */
+
+unrelocate_symbols (new, a_out, a_name, new_name)
+     int new, a_out;
+     char *a_name, *new_name;
+{
+  int i;
+  int l;
+  LDREL *ldrel;
+  LDHDR ldhdr;
+  LDREL ldrel_buf [20];
+  ulong t_reloc = (ulong) &_text - f_ohdr.text_start;
+  ulong d_reloc = (ulong) &_data - ALIGN(f_ohdr.data_start, 2);
+  int * p;
+
+  if (load_scnptr == 0)
+    return 0;
+
+  lseek (a_out, orig_load_scnptr, 0);
+  if (read (a_out, &ldhdr, sizeof (ldhdr)) != sizeof (ldhdr))
+    {
+      PERROR (new_name);
+    }
+
+#define SYMNDX_TEXT	0
+#define SYMNDX_DATA	1
+#define SYMNDX_BSS	2
+  l = 0;
+  for (i = 0; i < ldhdr.l_nreloc; i++, l--, ldrel++)
+    {
+      if (l == 0) {
+	lseek (a_out,
+	       orig_load_scnptr + LDHDRSZ + LDSYMSZ*ldhdr.l_nsyms + LDRELSZ*i,
+	       0);
+
+	l = ldhdr.l_nreloc - i;
+	if (l > sizeof (ldrel_buf) / LDRELSZ)
+	  l = sizeof (ldrel_buf) / LDRELSZ;
+
+	if (read (a_out, ldrel_buf, l * LDRELSZ) != l * LDRELSZ)
+	  {
+	    PERROR (a_name);
+	  }
+	ldrel = ldrel_buf;
+      }
+
+      /* move the BSS loader symbols to the DATA segment */
+      if (ldrel->l_symndx == SYMNDX_BSS)
+	{
+	  ldrel->l_symndx = SYMNDX_DATA;
+
+	  lseek (new,
+		 load_scnptr + LDHDRSZ + LDSYMSZ*ldhdr.l_nsyms + LDRELSZ*i,
+		 0);
+
+	  if (write (new, ldrel, LDRELSZ) != LDRELSZ)
+	    {
+	      PERROR (new_name);
+	    }
+	}
+
+      if (ldrel->l_rsecnm == f_ohdr.o_sndata)
+	{
+	  int orig_int;
+
+	  lseek (a_out,
+                 orig_data_scnptr + (ldrel->l_vaddr - f_ohdr.data_start), 0);
+
+	  if (read (a_out, (void *) &orig_int, sizeof (orig_int))
+	      != sizeof (orig_int))
+	    {
+	      PERROR (a_name);
+	    }
+
+          p = (int *) (ldrel->l_vaddr + d_reloc);
+
+	  switch (ldrel->l_symndx) {
+	  case SYMNDX_TEXT:
+	    orig_int = * p - t_reloc;
+	    break;
+
+	  case SYMNDX_DATA:
+	  case SYMNDX_BSS:
+	    orig_int = * p - d_reloc;
+	    break;
+	  }
+
+          if (orig_int != * p)
+            {
+              lseek (new,
+                     data_scnptr + (ldrel->l_vaddr - f_ohdr.data_start), 0);
+              if (write (new, (void *) &orig_int, sizeof (orig_int))
+                  != sizeof (orig_int))
+                {
+                  PERROR (new_name);
+                }
+            }
+	}
+    }
+}
+#endif /* XCOFF */