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/*
* Copyright (c) 1993, 1998 University of Utah and the Flux Group.
* All rights reserved.
*
* This file is part of the Flux OSKit. The OSKit is free software, also known
* as "open source;" you can redistribute it and/or modify it under the terms
* of the GNU General Public License (GPL), version 2, as published by the Free
* Software Foundation (FSF). To explore alternate licensing terms, contact
* the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271.
*
* The OSKit 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 GPL for more details. You should have
* received a copy of the GPL along with the OSKit; see the file COPYING. If
* not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
*/
/*
* Mach Operating System
* Copyright (c) 1993,1989 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
* i386-specific routines for loading a.out files.
*/
#include <oskit/exec/a.out.h>
#include <oskit/exec/exec.h>
/* See below...
Must be a power of two.
This should be kept small, because we may be running on a small stack,
and this code is not likely to be performance-critical anyway. */
#define SCAN_CHUNK 256
int exec_load_aout(exec_read_func_t *read, exec_read_exec_func_t *read_exec,
void *handle, exec_info_t *out_info)
{
struct exec x;
oskit_size_t actual;
oskit_addr_t text_start; /* text start in memory */
oskit_size_t text_size;
oskit_addr_t text_offset; /* text offset in file */
oskit_size_t data_size;
int err;
/* Read the exec header. */
err = (*read)(handle, 0, &x, sizeof(x), &actual);
if (err)
return err;
if (actual != sizeof(x))
return EX_NOT_EXECUTABLE;
/*printf("get_loader_info: magic %04o\n", (int)x.a_magic);*/
switch ((int)x.a_magic & 0xFFFF) {
case OMAGIC:
text_start = 0;
text_size = 0;
text_offset = sizeof(struct exec);
data_size = x.a_text + x.a_data;
break;
case NMAGIC:
text_start = 0;
text_size = x.a_text;
text_offset = sizeof(struct exec);
data_size = x.a_data;
break;
case ZMAGIC:
{
char buf[SCAN_CHUNK];
/* This kludge is not for the faint-of-heart...
Basically we're trying to sniff out the beginning of the text segment.
We assume that the first nonzero byte is the first byte of code,
and that x.a_entry is the virtual address of that first byte. */
for (text_offset = 0; ; text_offset++)
{
if ((text_offset & (SCAN_CHUNK-1)) == 0)
{
err = (*read)(handle, text_offset, buf,
SCAN_CHUNK, &actual);
if (err)
return err;
if (actual < SCAN_CHUNK)
buf[actual] = 0xff; /* ensure termination */
if (text_offset == 0)
text_offset = sizeof(struct exec);
}
if (buf[text_offset & (SCAN_CHUNK-1)])
break;
}
/* Account for the (unlikely) event that the first instruction
is actually an add instruction with a zero opcode.
Surely every a.out variant should be sensible enough at least
to align the text segment on a 32-byte boundary... */
text_offset &= ~0x1f;
text_start = x.a_entry;
text_size = x.a_text;
data_size = x.a_data;
break;
}
case QMAGIC:
text_start = 0x1000;
text_offset = 0;
text_size = x.a_text;
data_size = x.a_data;
break;
default:
/* Check for NetBSD big-endian ZMAGIC executable */
if ((int)x.a_magic == 0x0b018600) {
text_start = 0x1000;
text_size = x.a_text;
text_offset = 0;
data_size = x.a_data;
break;
}
return (EX_NOT_EXECUTABLE);
}
/* If the text segment overlaps the same page as the beginning of the data segment,
then cut the text segment short and grow the data segment appropriately. */
if ((text_start + text_size) & 0xfff)
{
oskit_size_t incr = (text_start + text_size) & 0xfff;
if (incr > text_size) incr = text_size;
text_size -= incr;
data_size += incr;
}
/*printf("exec_load_aout: text_start %08x text_offset %08x text_size %08x data_size %08x\n",
text_start, text_offset, text_size, data_size);*/
/* Load the read-only text segment, if any. */
if (text_size > 0)
{
err = (*read_exec)(handle, text_offset, text_size,
text_start, text_size,
EXEC_SECTYPE_READ |
EXEC_SECTYPE_EXECUTE |
EXEC_SECTYPE_ALLOC |
EXEC_SECTYPE_LOAD);
if (err)
return err;
}
/* Load the read-write data segment, if any. */
if (data_size + x.a_bss > 0)
{
err = (*read_exec)(handle,
text_offset + text_size,
data_size,
text_start + text_size,
data_size + x.a_bss,
EXEC_SECTYPE_READ |
EXEC_SECTYPE_WRITE |
EXEC_SECTYPE_EXECUTE |
EXEC_SECTYPE_ALLOC |
EXEC_SECTYPE_LOAD);
if (err)
return err;
}
/*
* Load the symbol table, if any.
* First the symtab, then the strtab.
*/
if (x.a_syms > 0)
{
unsigned strtabsize;
/* Load the symtab. */
err = (*read_exec)(handle,
text_offset + text_size + data_size,
x.a_syms,
0, 0,
EXEC_SECTYPE_AOUT_SYMTAB);
if (err)
return err;
/*
* Figure out size of strtab.
* The size is the first word and includes itself.
* If there is no strtab, this file is bogus.
*/
err = (*read)(handle,
text_offset + text_size + data_size + x.a_syms,
&strtabsize, sizeof(strtabsize),
&actual);
if (err)
return err;
if (actual != sizeof(strtabsize))
return EX_CORRUPT;
/* Load the strtab. */
err = (*read_exec)(handle,
text_offset + text_size + data_size + x.a_syms,
strtabsize,
0, 0,
EXEC_SECTYPE_AOUT_STRTAB);
if (err)
return err;
}
out_info->entry = x.a_entry;
return(0);
}
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