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/* Unexec for DEC alpha.
Copyright (C) 1994, 2000, 2001, 2002, 2003, 2004,
2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
Author: Rainer Schoepf <schoepf@sc.ZIB-Berlin.DE>
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 of the License, 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. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <stdio.h>
#include <errno.h>
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#if !defined (__NetBSD__) && !defined (__OpenBSD__)
#include <filehdr.h>
#include <aouthdr.h>
#include <scnhdr.h>
#include <syms.h>
#ifndef __linux__
# include <reloc.h>
# include <elf_abi.h>
#endif
#else /* __NetBSD__ or __OpenBSD__ */
/*
* NetBSD/Alpha does not have 'normal' user-land ECOFF support because
* there's no desire to support ECOFF as the executable format in the
* long term.
*/
#include <sys/exec_ecoff.h>
/* Structures, constants, etc., that NetBSD defines strangely. */
#define filehdr ecoff_filehdr
#define aouthdr ecoff_aouthdr
#define scnhdr ecoff_scnhdr
#define HDRR struct ecoff_symhdr
#define pHDRR HDRR *
#define cbHDRR sizeof(HDRR)
#ifdef __OpenBSD__
#define ALPHAMAGIC ECOFF_MAGIC_NATIVE_ALPHA
#else
#define ALPHAMAGIC ECOFF_MAGIC_NETBSD_ALPHA
#endif
#define ZMAGIC ECOFF_ZMAGIC
/* Misc. constants that NetBSD doesn't define at all. */
#define ALPHAUMAGIC 0617
#define _MIPS_NSCNS_MAX 35
#define STYP_TEXT 0x00000020
#define STYP_DATA 0x00000040
#define STYP_BSS 0x00000080
#define STYP_RDATA 0x00000100
#define STYP_SDATA 0x00000200
#define STYP_SBSS 0x00000400
#define STYP_INIT 0x80000000
#define _TEXT ".text"
#define _DATA ".data"
#define _BSS ".bss"
#define _INIT ".init"
#define _RDATA ".rdata"
#define _SDATA ".sdata"
#define _SBSS ".sbss"
#endif /* __NetBSD__ || __OpenBSD__ */
static void fatal_unexec __P ((char *, char *));
static void mark_x __P ((char *));
static void update_dynamic_symbols __P ((char *, char *, int, struct aouthdr));
#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);
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#else
void *sbrk ();
#endif
#define EEOF -1
static struct scnhdr *text_section;
static struct scnhdr *rel_dyn_section;
static struct scnhdr *dynstr_section;
static struct scnhdr *dynsym_section;
static struct scnhdr *init_section;
static struct scnhdr *finit_section;
static struct scnhdr *rdata_section;
static struct scnhdr *rconst_section;
static struct scnhdr *data_section;
static struct scnhdr *pdata_section;
static struct scnhdr *xdata_section;
static struct scnhdr *got_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;
static struct scnhdr old_data_scnhdr;
static unsigned long Brk;
struct headers {
struct filehdr fhdr;
struct aouthdr aout;
struct scnhdr section[_MIPS_NSCNS_MAX];
};
void
unexec (new_name, a_name, data_start, bss_start, entry_address)
char *new_name, *a_name;
unsigned long data_start, bss_start, entry_address;
{
int new, old;
char * oldptr;
struct headers ohdr, nhdr;
struct stat stat;
long pagesize, brk;
long newsyms, symrel;
int nread;
int i;
long vaddr, scnptr;
#define BUFSIZE 8192
char buffer[BUFSIZE];
if ((old = open (a_name, O_RDONLY)) < 0)
fatal_unexec ("opening %s", a_name);
new = creat (new_name, 0666);
if (new < 0) fatal_unexec ("creating %s", new_name);
if ((fstat (old, &stat) == -1))
fatal_unexec ("fstat %s", a_name);
oldptr = (char *)mmap (0, stat.st_size, PROT_READ, MAP_FILE|MAP_SHARED, old, 0);
if (oldptr == (char *)-1)
fatal_unexec ("mmap %s", a_name);
close (old);
/* This is a copy of the a.out header of the original executable */
ohdr = (*(struct headers *)oldptr);
/* This is where we build the new header from the in-memory copy */
nhdr = *((struct headers *)TEXT_START);
/* First do some consistency checks */
if (nhdr.fhdr.f_magic != ALPHAMAGIC
&& nhdr.fhdr.f_magic != ALPHAUMAGIC)
{
fprintf (stderr, "unexec: input file magic number is %x, not %x or %x.\n",
nhdr.fhdr.f_magic, ALPHAMAGIC, ALPHAUMAGIC);
exit (1);
}
if (nhdr.fhdr.f_opthdr != sizeof (nhdr.aout))
{
fprintf (stderr, "unexec: input a.out header is %d bytes, not %d.\n",
nhdr.fhdr.f_opthdr, (int)sizeof (nhdr.aout));
exit (1);
}
if (nhdr.aout.magic != ZMAGIC)
{
fprintf (stderr, "unexec: input file a.out magic number is %o, not %o.\n",
nhdr.aout.magic, ZMAGIC);
exit (1);
}
/* Now check the existence of certain header section and grab
their addresses. */
#define CHECK_SCNHDR(ptr, name, flags) \
ptr = NULL; \
for (i = 0; i < nhdr.fhdr.f_nscns && !ptr; i++) \
if (strncmp (nhdr.section[i].s_name, name, 8) == 0) \
{ \
if (nhdr.section[i].s_flags != flags) \
fprintf (stderr, "unexec: %x flags (%x expected) in %s section.\n", \
nhdr.section[i].s_flags, flags, name); \
ptr = nhdr.section + i; \
} \
CHECK_SCNHDR (text_section, _TEXT, STYP_TEXT);
CHECK_SCNHDR (init_section, _INIT, STYP_INIT);
#ifdef _REL_DYN
CHECK_SCNHDR (rel_dyn_section, _REL_DYN, STYP_REL_DYN);
#endif /* _REL_DYN */
#ifdef _DYNSYM
CHECK_SCNHDR (dynsym_section, _DYNSYM, STYP_DYNSYM);
#endif /* _REL_DYN */
#ifdef _DYNSTR
CHECK_SCNHDR (dynstr_section, _DYNSTR, STYP_DYNSTR);
#endif /* _REL_DYN */
#ifdef _FINI
CHECK_SCNHDR (finit_section, _FINI, STYP_FINI);
#endif /* _FINI */
CHECK_SCNHDR (rdata_section, _RDATA, STYP_RDATA);
#ifdef _RCONST
CHECK_SCNHDR (rconst_section, _RCONST, STYP_RCONST);
#endif
#ifdef _PDATA
CHECK_SCNHDR (pdata_section, _PDATA, STYP_PDATA);
#endif /* _PDATA */
#ifdef _GOT
CHECK_SCNHDR (got_section, _GOT, STYP_GOT);
#endif /* _GOT */
CHECK_SCNHDR (data_section, _DATA, STYP_DATA);
#ifdef _XDATA
CHECK_SCNHDR (xdata_section, _XDATA, STYP_XDATA);
#endif /* _XDATA */
#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);
pagesize = getpagesize ();
brk = (((long) (sbrk (0))) + pagesize - 1) & (-pagesize);
/* Remember the current break */
Brk = brk;
bcopy (data_section, &old_data_scnhdr, sizeof (old_data_scnhdr));
nhdr.aout.dsize = brk - DATA_START;
nhdr.aout.bsize = 0;
if (entry_address == 0)
{
extern __start ();
nhdr.aout.entry = (unsigned long)__start;
}
else
nhdr.aout.entry = entry_address;
nhdr.aout.bss_start = nhdr.aout.data_start + nhdr.aout.dsize;
if (rdata_section != NULL)
{
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 + nhdr.aout.tsize;
}
data_section->s_vaddr = data_start;
data_section->s_paddr = data_start;
data_section->s_size = brk - data_start;
if (rdata_section != NULL)
{
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;
}
#ifdef _XDATA
if (xdata_section != NULL)
{
xdata_section->s_vaddr = vaddr;
xdata_section->s_paddr = vaddr;
xdata_section->s_size = 0;
xdata_section->s_scnptr = scnptr;
}
#endif
#ifdef _GOT
if (got_section != NULL)
{
bcopy (got_section, buffer, sizeof (struct scnhdr));
got_section->s_vaddr = vaddr;
got_section->s_paddr = vaddr;
got_section->s_size = 0;
got_section->s_scnptr = scnptr;
}
#endif /*_GOT */
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, nhdr.aout.tsize,
"writing text section to %s", new_name);
WRITE (new, (char *)DATA_START, nhdr.aout.dsize,
"writing data section to %s", new_name);
#ifdef _GOT
#define old_got_section ((struct scnhdr *)buffer)
if (got_section != NULL)
{
SEEK (new, old_got_section->s_scnptr,
"seeking to start of got_section in %s", new_name);
WRITE (new, oldptr + old_got_section->s_scnptr, old_got_section->s_size,
"writing new got_section of %s", new_name);
SEEK (new, nhdr.aout.tsize + nhdr.aout.dsize,
"seeking to end of data section of %s", new_name);
}
#undef old_got_section
#endif
/*
* Construct new symbol table header
*/
bcopy (oldptr + nhdr.fhdr.f_symptr, buffer, cbHDRR);
#define symhdr ((pHDRR)buffer)
newsyms = nhdr.aout.tsize + nhdr.aout.dsize;
symrel = newsyms - nhdr.fhdr.f_symptr;
nhdr.fhdr.f_symptr = newsyms;
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;
WRITE (new, buffer, cbHDRR, "writing symbol table header of %s", new_name);
/*
* Copy the symbol table and line numbers
*/
WRITE (new, oldptr + ohdr.fhdr.f_symptr + cbHDRR,
stat.st_size - ohdr.fhdr.f_symptr - cbHDRR,
"writing symbol table of %s", new_name);
#ifdef _REL_DYN
if (rel_dyn_section)
update_dynamic_symbols (oldptr, new_name, new, nhdr.aout);
#endif
#undef symhdr
SEEK (new, 0, "seeking to start of header in %s", new_name);
WRITE (new, &nhdr, sizeof (nhdr),
"writing header of %s", new_name);
close (old);
close (new);
mark_x (new_name);
}
static void
update_dynamic_symbols (old, new_name, new, aout)
char *old; /* Pointer to old executable */
char *new_name; /* Name of new executable */
int new; /* File descriptor for new executable */
struct aouthdr aout; /* a.out info from the file header */
{
#if !defined (__linux__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
typedef struct dynrel_info {
char * addr;
unsigned type:8;
unsigned index:24;
unsigned info:8;
unsigned pad:8;
} dr_info;
int nsyms = rel_dyn_section->s_size / sizeof (struct dynrel_info);
int i;
dr_info * rd_base = (dr_info *) (old + rel_dyn_section->s_scnptr);
Elf32_Sym * ds_base = (Elf32_Sym *) (old + dynsym_section->s_scnptr);
for (i = 0; i < nsyms; i++) {
register Elf32_Sym x;
if (rd_base[i].index == 0)
continue;
x = ds_base[rd_base[i].index];
#if 0
fprintf (stderr, "Object inspected: %s, addr = %lx, shndx = %x",
old + dynstr_section->s_scnptr + x.st_name, rd_base[i].addr, x.st_shndx);
#endif
if ((ELF32_ST_BIND (x.st_info) == STB_GLOBAL)
&& (x.st_shndx == 0)
/* && (x.st_value == NULL) */
) {
/* OK, this is probably a reference to an object in a shared
library, so copy the old value. This is done in several steps:
1. reladdr is the address of the location in question relative to
the start of the data section,
2. oldref is the addr is the mapped in temacs executable,
3. newref is the address of the location in question in the
undumped executable,
4. len is the size of the object reference in bytes --
currently only 4 (long) and 8 (quad) are supported.
*/
register unsigned long reladdr = (long)rd_base[i].addr - old_data_scnhdr.s_vaddr;
char * oldref = old + old_data_scnhdr.s_scnptr + reladdr;
unsigned long newref = aout.tsize + reladdr;
int len;
#if 0
fprintf (stderr, "...relocated\n");
#endif
if (rd_base[i].type == R_REFLONG)
len = 4;
else if (rd_base[i].type == R_REFQUAD)
len = 8;
else
fatal_unexec ("unrecognized relocation type in .dyn.rel section (symbol #%d)", (char *) i);
SEEK (new, newref, "seeking to dynamic symbol in %s", new_name);
WRITE (new, oldref, len, "writing old dynrel info in %s", new_name);
}
#if 0
else
fprintf (stderr, "...not relocated\n");
#endif
}
#endif /* not __linux__ and not __NetBSD__ and not __OpenBSD__ */
}
/*
* 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, arg)
char *s;
char *arg;
{
if (errno == EEOF)
fputs ("unexec: unexpected end of file, ", stderr);
else
fprintf (stderr, "unexec: %s, ", strerror (errno));
fprintf (stderr, s, arg);
fputs (".\n", stderr);
exit (1);
}
/* arch-tag: 46316c49-ee08-4aa3-942b-00798902f5bd
(do not change this comment) */
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