Autah-gr.149

Autah-gr.149
net.sources
utcsrgv!utzoo!decvax!ucbvax!ihnss!cbosg!harpo!utah-cs!utah-gr!thomas
Fri Feb 19 17:35:10 1982
Core -> a.out conversion program
This program was advertised on unix-wizards. I have had such a large
response I'm sending it out to the world.

Here is the source. It works fine under 4.1bsd, I see no fundamental
reason why it shouldn't work on an 11. (Except possibly small format
changes in exec header or user structure.) No documentation yet.
Usage is
% undump new-a.out-file [old-a.out-file] [core-file]
where old-a.out-file and core-file default to "a.out" and "core",
respectively. Probably should have an option to not require
old-a.out-file if the core came from a 407 file.

It doesn't preserve open files, and the program is re-entered at main
when you run it. It's used locally to dump a lisp and restart it.

It requires a local subroutine called scanargs, somewhat similar to
getopt (I think). You should be able to easily get around this, though.
=Spencer

/*
* undump.c - Convert a core file to an a.out.
*
* Author: Spencer W. Thomas
* Computer Science Dept.
* University of Utah
* Date: Wed Feb 17 1982
* Copyright (c) 1982 Spencer W. Thomas
*
* Usage:
* undump new-a.out [a.out] [core]
*/

#include <STDIO.H>
#include <SYS/PARAM.H>
#include <SYS/DIR.H>
#include <SYS/USER.H>
#include <STAT.H>
#include <A.OUT.H>
#include <CORE.H>

#define PSIZE 10240

struct user u;
struct exec hdr, ohdr;

main(argc, argv)
char **argv;
{
char *new_name, *a_out_name = "a.out", *core_name = "core";
FILE *new, *a_out, *core;

if (scanargs(argc, argv, "undump new-a.out!s a.out%s core%s",
&new_name, &a_out_name, &core_name)
!= 1)
exit(1);

if ((a_out = fopen(a_out_name, "r")) == NULL)
{
perror(a_out_name);
exit(1);
}
if ((core = fopen(core_name, "r")) == NULL)
{
perror(core_name);
exit(1);
}
if ((new = fopen(new_name, "w")) == NULL)
{
perror(new_name);
exit(1);
}

read_u(core);
make_hdr(new, a_out);
copy_text(new, a_out);
copy_data(new, core);
copy_sym(new, a_out);
fclose(new);
fclose(core);
fclose(a_out);
mark_x(new_name);
}

/*
* read the u structure from the core file.
*/
read_u(core)
FILE *core;
{
if ( fread(&u, sizeof u, 1, core) != 1 )
{
perror("Couldn't read user structure from core file");
exit(1);
}
}

/*
* Make the header in the new a.out from the header in the old one
* modified by the new data size.
*/
make_hdr(new, a_out)
FILE *new, *a_out;
{
if (fread(&hdr, sizeof hdr, 1, a_out) != 1)
{
perror("Couldn't read header from a.out file");
exit(1);
}
ohdr = hdr;
if N_BADMAG(hdr)
{
fprintf(stderr, "a.out file doesn't have legal magic number\n");
exit(1);
}
if (hdr.a_magic != u.u_exdata.ux_mag ||
hdr.a_text != u.u_exdata.ux_tsize ||
hdr.a_data != u.u_exdata.ux_dsize ||
hdr.a_entry != u.u_exdata.ux_entloc)
{
fprintf(stderr, "Core file didn't come from this a.out\n");
exit(1);
}

printf("Data segment size was %u", hdr.a_data);
hdr.a_data = ctob(u.u_dsize);
hdr.a_bss = 0; /* all data is inited now! */
printf(" now is %u\n", hdr.a_data);
if (fwrite(&hdr, sizeof hdr, 1, new) != 1)
{
perror("Couldn't write header to new a.out file");
exit(1);
}
}

/*
* Copy the text from the a.out to the new a.out
*/
copy_text(new, a_out)
FILE *new, *a_out;
{
char page[PSIZE];
int txtcnt = hdr.a_text;

fseek(new, N_TXTOFF(hdr), 0);
fseek(a_out, N_TXTOFF(hdr), 0);
if (hdr.a_magic == OMAGIC)
{
printf("a.out file is not shared text, getting text from core file\n");
fseek(a_out, hdr.a_text, 1); /* skip over text */
return;
}
while (txtcnt >= PSIZE)
{
if (fread(page, PSIZE, 1, a_out) != 1)
{
perror("Read failure on a.out text");
exit(1);
}
if (fwrite(page, PSIZE, 1, new) != 1)
{
perror("Write failure in text segment");
exit(1);
}
txtcnt -= PSIZE;
}
if (txtcnt)
{
if (fread(page, txtcnt, 1, a_out) != 1)
{
perror("Read failure on a.out text");
exit(1);
}
if (fwrite(page, txtcnt, 1, new) != 1)
{
perror("Write failure in text segment");
exit(1);
}
}
}

/*
* copy the data from the core file to the new a.out
*/
copy_data(new, core)
FILE *new, *core;
{
char page[PSIZE];
int datacnt = ctob(u.u_dsize);

if (hdr.a_magic == OMAGIC)
datacnt += u.u_tsize;
fseek(core, ctob(UPAGES), 0);
while (datacnt >= PSIZE)
{
if (fread(page, PSIZE, 1, core) != 1)
{
perror("Read failure on core data");
exit(1);
}
if (fwrite(page, PSIZE, 1, new) != 1)
{
perror("Write failure in data segment");
exit(1);
}
datacnt -= PSIZE;
}
if (datacnt)
{
if (fread(page, datacnt, 1, core) != 1)
{
perror("Read failure on core data");
exit(1);
}
if (fwrite(page, datacnt, 1, new) != 1)
{
perror("Write failure in data segment");
exit(1);
}
}
}

/*
* Copy the relocation information and symbol table from the a.out to the new
*/
copy_sym(new, a_out)
FILE *new, *a_out;
{
char page[PSIZE];
int n;

fseek(a_out, ohdr.a_data, 1); /* skip over data segment */
while ((n = fread(page, 1, PSIZE, a_out)) > 0)
{
if (fwrite(page, 1, n, new) != n)
{
perror("Error writing symbol table to new a.out");
fprintf(stderr, "new a.out should be ok otherwise\n");
return;
}
}
if (n
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2. The following notice remains appended to each copy:

The Usenet Oldnews Archive: Compilation Copyright&copy 1981, 1996
 Bruce Jones, Henry Spencer, David Wiseman.

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This Usenet Oldnews Archive
article may be copied and distributed freely, provided:

1. There is no money collected for the text(s) of the articles.

2. The following notice remains appended to each copy:

The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996
Bruce Jones, Henry Spencer, David Wiseman.