Article: 631 of unix-pc.sources
From: lenny@icus.ICUS.COM (Lenny Tropiano)
Newsgroups: unix-pc.sources
Subject: undump.shar - create an initialized binary from binary and core.
Keywords: undump, core, initialized
Message-ID: <1211@icus.ICUS.COM>
Date: 26 Jun 90 19:15:31 GMT
Reply-To: alex@otter.acslab.umbc.edu (Alex S. Crain)
Distribution: unix-pc
Organization: ICUS Software Systems, Islip, New York
Lines: 459

Alex's new postings to unix-pc.sources never arrived anywhere that I could
see.  I asked Alex to mail them to me, and I would post them on his
behalf.  Any questions, problems, bugs, etc, should go to him... :-)

-- cut here for undump.shar -- -- cut here for undump.shar --

#! /bin/sh
# This is a shell archive.  Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file".  To overwrite existing
# files, type "sh file -c".  You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g..  If this archive is complete, you
# will see the following message at the end:
#		"End of shell archive."
# Contents:  undump.1 undump.c
# Wrapped by alex@umbc5.umbc.edu on Wed Jun 20 16:57:32 1990
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'undump.1' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'undump.1'\"
else
echo shar: Extracting \"'undump.1'\" \(1179 characters\)
sed "s/^X//" >'undump.1' <<'END_OF_FILE'
X.TH UNDUMP 1 "University of Utah"
X.SH NAME
Xundump \- convert a core dump to an executable a.out file
X.SH SYNOPSIS
Xundump new-a.out-file [old-a.out-file] [core-file]
X.SH DESCRIPTION
XUndump takes a core dump file and the executable "a.out" file which
Xcaused it and produces a new executable file with all static
Xvariables initialized to the values they held at the time of the
Xcore dump.  It is primarily useful for programs which take a long time
Xto initialize themselves, e.g., Emacs.  The idea is to go through all of
Xthe initializations and then create a core dump (e.g., with the abort()
Xcall).  One then uses undump to make a new executable file with all of it
Xdone.  This usually implies the use of a global flag variable which says
Xwhether or not initialization has been done.
X.PP
XUndump's arguments, old-a.out-file and core-file, default to "a.out" and
X"core", respectively.
X.PP
XA few things to keep in mind about undump:
X.IP
XIt doesn't preserve open files.
X.IP
XThe program will be re-entered at the beginning of main(), not at the point
Xwhere the core dump occurred.
X.SH BUGS
XProbably should have an option to not require
Xold-a.out-file if the core came from a 407 file.
END_OF_FILE
if test 1179 -ne `wc -c <'undump.1'`; then
    echo shar: \"'undump.1'\" unpacked with wrong size!
fi
# end of 'undump.1'
fi
if test -f 'undump.c' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'undump.c'\"
else
echo shar: Extracting \"'undump.c'\" \(9561 characters\)
sed "s/^X//" >'undump.c' <<'END_OF_FILE'
X/*
X * undump - resurrect a core file into a runnable program.
X *
X *	for UNIX System V on a 3Bx
X *	that uses the Common Object File Format
X *
X * Author:
X *	Lou Salkind
X *	New York University
X *	Tue Mar  3 13:18:25 EST 1987
X *
X * Adapted from:
X *	Spencer Thomas's undump and the file unexec.c in GNU emacs
X *
X * Modified:
X *	Brant Cheikes
X *	University of Pennsylvania
X *	Department of Computer and Information Science
X *	ARPA: brant@linc.cis.upenn.edu, UUCP: ...drexel!manta!brant
X *	Wed Jun  1 00:57:16 EDT 1988
X *	Patched to make it fly on an AT&T UNIXpc (aka PC7300, 3b1).
X *	Bug: undump currently won't dump out line numbers, symbol
X *	table entries, or the string table.  Thus the resulting
X *	a.out looks like the result of an ld with the -s (strip)
X *	option.
X *
X * Modified:
X *	Alex Crain
X *	Patched to fix the symbol table entries (which now work).
X *
X */
X
X#include <sys/param.h>
X#include <sys/types.h>
X#include <sys/signal.h>
X#include <sys/user.h>
X
X#include <stdio.h>
X#include <sys/stat.h>
X
X#include <aouthdr.h>
X#include <filehdr.h>
X#include <scnhdr.h>
X#include <syms.h>
X
X#define	PAGE_SIZE	NBPC	/* size of a page in bytes */
X
Xstruct filehdr fh;		/* file header */
XAOUTHDR aout;			/* optional header */
Xstruct scnhdr tsc;		/* text section header */
Xstruct scnhdr dsc;		/* data section header */
Xstruct scnhdr bsc;		/* bss section header */
X#ifdef UNIXPC
Xstruct scnhdr lsc;		/* shared lib section header */
X#endif /* UNIXPC */
X
Xlong text_scnptr;
Xlong data_scnptr;
Xlong bias;
Xlong lnnoptr;
Xlong symlocptr;
X
Xmain(argc, argv)
X     char **argv;
X{
X  FILE *afp, *cfp, *nfp;
X  struct user u;
X  long off, size;
X  struct scnhdr sc;
X  int i;
X  char *a_out_name = "a.out";
X  char *core_name = "core";
X  char *new_name;
X  
X  if (argc < 2 || argc > 4) {
X    fprintf(stderr,"Usage: %s new [a.out [core]]\n", argv[0]);
X    exit(1);
X  }
X
X  new_name = argv[1];
X  nfp = fopen(new_name, "w");
X  if (nfp == 0)
X    Perror(new_name);
X
X  if (argc > 2)
X    a_out_name = argv[2];
X  afp = fopen(a_out_name, "r");
X  if (afp == 0)
X    Perror(a_out_name);
X
X  if (argc > 3)
X    core_name = argv[3];
X  cfp = fopen(core_name, "r");
X  if (cfp == 0)
X    Perror(core_name);
X  
X  /*
X   * Read in the file header and optional file header from
X   * the a.out file.
X   */
X  if (fread(&fh, sizeof(fh), 1, afp) != 1)
X    Perror("fh read");
X  if (fread(&aout, sizeof(aout), 1, afp) != 1)
X    Perror("aout read");
X  
X  /*
X   * Read in the various section headers.
X   */
X  for (i = 0; i < fh.f_nscns; i++) {
X    if (fread(&sc, sizeof(sc), 1, afp) != 1)
X      Perror("scnhdr read");
X    if (strcmp(sc.s_name, ".text") == 0) {
X      tsc = sc;
X    } else if (strcmp(sc.s_name, ".data") == 0) {
X      dsc = sc;
X    } else if (strcmp(sc.s_name, ".bss") == 0) {
X      bsc = sc;
X#ifdef UNIXPC
X    } else if (strcmp(sc.s_name, ".lib") == 0) {
X      lsc = sc;
X#endif /* UNIXPC */
X    }
X  }
X  
X#ifdef UNIXPC
X  /*
X   * The kernel stack (I think) takes up the first U_OFFSET
X   * bytes of the core file, followed by the user structure.
X   * Skip past that junk and get down to the nitty-gritty.
X   */
X  fseek(cfp, (long)U_OFFSET, 0);
X#endif /* UNIXPC */
X  
X  /*
X   * Read in the user structure from the core file and perform
X   * a sanity check.
X   */
X  if (fread(&u, sizeof(u), 1, cfp) != 1)
X    Perror("core read");
X  if (u.u_exdata.ux_tsize != aout.tsize ||
X      u.u_exdata.ux_dsize != aout.dsize ||
X      u.u_exdata.ux_bsize != aout.bsize) {
X    fprintf(stderr,"mismatch between %s and %s sizes\n",a_out_name, core_name);
X    exit(1);
X  }
X  
X  /*
X   * off = offset to start of actual mem dump data in core file.
X   * size = size of new .data section.
X   */
X  off = USIZE*PAGE_SIZE;
X  size = u.u_dsize * PAGE_SIZE;
X  
X  fh.f_flags |= F_RELFLG | F_EXEC;
X  /*
X   * .data section size of new a.out = data size at time of
X   * core dump.  .bss size is now zero (no uninitialized data).
X   */
X  aout.dsize = size;
X  aout.bsize = 0;
X  
X  /*
X   * text size same as text size of a.out.
X   */
X  tsc.s_size = aout.tsize;
X#ifndef UNIXPC
X  /*
X   * I'm commenting out the following code, since I believe we can use
X   * unmodified the scnptr of the text section stored in the original
X   * a.out.  Nothing we have done needs to alter its starting point.
X   * In fact, we arguably SHOULDN'T alter the text starting point, since
X   * certain kinds of files require special alignments of text and data
X   * sections, both in memory and in the file.  If it ain't broke, don't
X   * fix it.
X   */
X  tsc.s_scnptr = sizeof(fh) + sizeof(aout);
X  tsc.s_scnptr += fh.f_nscns * sizeof (struct scnhdr);
X#endif /* not UNIXPC */
X  text_scnptr = tsc.s_scnptr;
X
X  lnnoptr = tsc.s_lnnoptr;
X  symlocptr = fh.f_symptr;
X  if (lnnoptr == 0)
X    lnnoptr = symlocptr;
X  
X#ifndef UNIXPC
X  /*
X   * I'm going to assume that the .text section size never
X   * grows.  Thus, we need not tweak the paddr and vaddr of
X   * the .data section, since its start point has not moved.
X   */
X  dsc.s_paddr = dsc.s_vaddr = aout.data_start;
X#endif /* not UNIXPC */
X  
X  /*
X   * New .data size is computed from core dump.
X   * Initialize pointer to raw .data section in the file.
X   */
X  dsc.s_size = size;
X  dsc.s_scnptr = tsc.s_scnptr + tsc.s_size;
X#ifdef UNIXPC
X  /*
X   * Magic 0413 files require that the .data section be aligned
X   * on a 1024 byte boundary IN THE FILE.
X   */
X  if (u.u_exdata.ux_mag == 0413)
X    dsc.s_scnptr = (dsc.s_scnptr + 0x400) & ~0x3ff;
X#endif /* UNIXPC */
X  data_scnptr = dsc.s_scnptr;
X  
X  /*
X   * Tweak .bss header values.
X   */
X  bsc.s_paddr = bsc.s_vaddr = aout.data_start + aout.dsize;
X  bsc.s_size = aout.bsize;
X  bsc.s_scnptr = 0L;
X  
X#ifdef UNIXPC
X  /*
X   * Adjust the physical/virtual addresses of the shared lib,
X   * if present.  Basically, since the .bss section has just
X   * disappeared, the shlib and .bss end up with the same addresses.
X   */
X  if (fh.f_nscns > 3) {
X    lsc.s_paddr = lsc.s_vaddr = aout.data_start + aout.dsize;
X    lsc.s_size = lsc.s_scnptr = 0L;
X  }
X#endif /* UNIXPC */
X  
X  bias = dsc.s_scnptr + dsc.s_size - lnnoptr;
X  if (fh.f_symptr > 0L)
X    fh.f_symptr += bias;
X  if (tsc.s_lnnoptr > 0L)
X    tsc.s_lnnoptr += bias;
X  
X  /*
X   * Write out the file header, optional file header, and the
X   * various section headers.
X   */
X  if (fwrite(&fh, sizeof(fh), 1, nfp) != 1)
X    Perror("fh write");
X  if (fwrite(&aout, sizeof(aout), 1, nfp) != 1)
X    Perror("aout write");
X  if (fwrite(&tsc, sizeof(tsc), 1, nfp) != 1)
X    Perror("ts hdr write");
X  if (fwrite(&dsc, sizeof(dsc), 1, nfp) != 1)
X    Perror("ds hdr write");
X  if (fwrite(&bsc, sizeof(bsc), 1, nfp) != 1)
X    Perror("bs hdr write");
X#ifdef UNIXPC
X  /*
X   * Dump out shared lib section header, if it was present
X   * in the old a.out.
X   */
X  if (fh.f_nscns > 3)
X    if (fwrite(&lsc, sizeof(lsc), 1, nfp) != 1)
X      Perror("lib hdr write");
X#endif /* UNIXPC */
X  
X  /*
X   * Hokay, set position in core file to right after user structure.
X   * Position in new a.out to where text_scnptr says.
X   */
X  fseek(cfp, off, 0);
X  fseek(nfp, text_scnptr, 0);
X#ifdef UNIXPC
X  /*
X   * If we have a 0407 file, then we have to copy the text from
X   * the core file.  If not, we copy the text from the original
X   * a.out.
X   */
X  if (u.u_exdata.ux_mag == 0407)
X    copy(cfp, nfp, aout.tsize);
X  else {
X    fseek(afp, text_scnptr, 0);
X    copy(afp, nfp, aout.tsize);
X  }
X#else
X  copy(afp, nfp, aout.tsize);
X#endif
X  fseek(nfp, data_scnptr, 0);
X  copy(cfp, nfp, size);
X  copy_syms(afp, nfp);
X  fclose(nfp);
X  fclose(afp);
X  fclose(cfp);
X  mark_x(new_name);
X  exit(0);
X}
X
Xcopy_syms(afp, nfp)
X     register FILE *afp, *nfp;
X{
X  char page[BUFSIZ];
X  register int n;
X  register int nsyms;
X  struct syment symentry;
X  AUXENT auxentry;
X  
X  /* if there are line numbers, copy them */
X  if (lnnoptr) {
X    if (fseek(afp, lnnoptr, 0) == -1L)
X      Perror("ln fseek");
X    copy(afp, nfp, symlocptr - lnnoptr);
X  }
X  
X  /* now write the symbol table */
X  if (fseek(nfp, fh.f_symptr, 0) == -1L)
X    Perror("symtbl fseek");
X  for (nsyms = 0; nsyms < fh.f_nsyms; nsyms++) {
X    if (fread(&symentry, SYMESZ, 1, afp) != 1)
X      Perror("sym fread");
X    if (fwrite(&symentry, SYMESZ, 1, nfp) != 1)
X      Perror("sym fwrite");
X    /*
X     * adjust relative offsets of line numbers for
X     * function definitions
X     */
X    if (symentry.n_numaux) {
X      if (fread(&auxentry, AUXESZ, 1, afp) != 1)
X	Perror("aux fread");
X      nsyms++;
X      if (ISFCN (symentry.n_type))
X	auxentry.x_sym.x_fcnary.x_fcn.x_lnnoptr += bias;
X      if (fwrite(&auxentry, AUXESZ, 1, nfp) != 1)
X	Perror("aux fwrite");
X    }
X  }
X  
X  /* finally write the string table, if any */
X  while ((n = fread(page, 1, sizeof(page), afp)) > 0) {
X    if (fwrite(page, 1, n, nfp) != n)
X      Perror("sym write");
X  }
X  if (n < 0)
X    Perror("sym read");
X}
X
X/*
X * After succesfully building the new a.out, mark it executable
X */
Xmark_x(name)
X     char *name;
X{
X  struct stat sbuf;
X  int um;
X  
X  um = umask(777);
X  umask(um);
X  if (stat(name, &sbuf) == -1) {
X    perror ("Can't stat new a.out");
X    fprintf(stderr, "Setting protection to %o\n", 0777 & ~um);
X    sbuf.st_mode = 0777;
X  }
X  sbuf.st_mode |= 0111 & ~um;
X  if (chmod(name, sbuf.st_mode) == -1)
X    Perror("Couldn't mark new a.out executable");
X  
X}
X
Xcopy(a, b, size)
X     register FILE *a, *b;
X     long size;
X{
X  char buf[BUFSIZ];
X  register int i, n;
X  
X  while (size > 0) {
X    i = size;
X    if (i > sizeof(buf))
X      i = sizeof(buf);
X    if ((n = fread(buf, 1, i, a)) <= 0)
X      Perror("copy read");
X    if (fwrite(buf, 1, n, b) != n)
X      Perror("copy write");
X    size -= n;
X  }
X}
X
XPerror(s)
X     char *s;
X{
X  perror(s);
X  exit(1);
X}
X
END_OF_FILE
if test 9561 -ne `wc -c <'undump.c'`; then
    echo shar: \"'undump.c'\" unpacked with wrong size!
fi
# end of 'undump.c'
fi
echo shar: End of shell archive.
exit 0

-- 
| Lenny Tropiano           ICUS Software Systems        lenny@icus.ICUS.COM |
| {ames,pacbell,decuac,sbcs,hombre,rayssd}!icus!lenny   attmail!icus!lenny  |
+------ ICUS Software Systems --  PO Box 1;  Islip Terrace, NY  11752 ------+