/* Dump an executable image.
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 3 of the License, 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. If not, see . */
/* Synched up with: FSF 20.2. */
/* This file has been ... uhhhhh ... Mule-ized. Yeah.
(Everything here is external format. That's potentially dangerous,
but in practice it'll be OK.) --ben */
/* Originally based on the COFF unexec.c by Spencer W. Thomas.
*
* Subsequently hacked on by
* Bill Mann
* Andrew Vignaux
* Mike Sperber
*
* 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.
*
* data_start and entry_address are ignored.
*
* 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
* sbrk(2).
*
*/
#ifndef emacs
#define PERROR(arg) perror (arg); return -1
#else
#include
#define PERROR(file) report_error (file, new_)
#endif
#include
/* Define getpagesize () if the system does not.
Note that this may depend on symbols defined in a.out.h
*/
#include "getpagesize.h"
#include
#include
#include
#include
#include
#include
extern char *start_of_text (void); /* Start of text */
extern char *start_of_data (void); /* Start of initialized data */
extern int _data;
extern int _text;
#include
#include
#include
#include
static struct filehdr f_hdr; /* File header */
static struct aouthdr f_ohdr; /* Optional file header (a.out) */
static long bias; /* Bias to add for growth */
static long lnnoptr; /* Pointer to line-number info within file */
static long text_scnptr;
static long data_scnptr;
#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;
static int unrelocate_symbols (int, int, char *, char *);
#ifndef MAX_SECTIONS
#define MAX_SECTIONS 10
#endif
static int adjust_lnnoptrs (int, int, char *);
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 void
report_error (char *file, int fd)
{
if (fd)
close (fd);
report_error_with_errno (Qio_error, "Cannot unexec",
build_cistring (file));
}
#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 void
report_error_1 (int fd, char *msg, int a1, int a2)
{
close (fd);
#ifdef emacs
signal_ferror (Qio_error, msg, a1, a2);
#else
fprintf (stderr, msg, a1, a2);
fprintf (stderr, "\n");
#endif
}
static int make_hdr (int, int, unsigned, unsigned, unsigned, char *, char *);
static void mark_x (char *);
static int copy_text_and_data (int);
static int copy_sym (int, int, char *, char *);
static void write_segment (int, char *, char *);
/* ****************************************************************
* unexec
*
* driving logic.
*/
int unexec (char *new_name, char *a_name,
uintptr_t data_start,
uintptr_t bss_start,
uintptr_t entry_address)
{
int new_ = -1, a_out = -1;
if (a_name && (a_out = open (a_name, O_RDONLY)) < 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
|| adjust_lnnoptrs (new_, a_out, new_name) < 0
|| unrelocate_symbols (new_, a_out, a_name, new_name) < 0)
{
close (new_);
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 (int new_, int a_out,
unsigned data_start, unsigned bss_start,
unsigned UNUSED (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. */
data_start = (long) start_of_data ();
data_start = ADDR_CORRECT (data_start);
data_start = data_start & ~pagemask; /* (Down) to page boundary. */
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);
}
/* 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 = §ion[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", (int) _TEXT);
}
if (f_dhdr == 0)
{
ERROR1 ("unexec: couldn't find \"%s\" section", (int) _DATA);
}
if (f_bhdr == 0)
{
ERROR1 ("unexec: couldn't find \"%s\" section", (int) _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);
f_ohdr.dsize = bss_start - f_ohdr.data_start;
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 = §ion[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 = §ion[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;
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 = §ion[scns];
if (write (new_, s, sizeof (*s)) != sizeof (*s))
{
PERROR (new_name);
}
}
return (0);
}
/* ****************************************************************
*
* Copy the text and data segments from memory to the new a.out
*/
static int
copy_text_and_data (int new_)
{
char *end;
char *ptr;
lseek (new_, (long) text_scnptr, SEEK_SET);
ptr = start_of_text () + text_scnptr;
end = ptr + f_ohdr.tsize;
write_segment (new_, ptr, end);
lseek (new_, (long) data_scnptr, SEEK_SET);
ptr = (char *) f_ohdr.data_start;
end = ptr + f_ohdr.dsize;
write_segment (new_, ptr, end);
return 0;
}
#define UnexBlockSz (1<<12) /* read/write block size */
static void
write_segment (int new_, char *ptr, char *end)
{
int i, nwrite, ret;
char buf[80];
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)
{
memset (zeros, 0, 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 (int new_, int a_out, char *a_name, char *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, SEEK_SET); /* start copying from there */
else
lseek (a_out, orig_load_scnptr, SEEK_SET); /* 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 (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);
}
static int
adjust_lnnoptrs (int UNUSED (writedesc), int UNUSED (readdesc), char *new_name)
{
int nsyms;
int naux;
int new_;
struct syment symentry;
union auxent auxentry;
if (!lnnoptr || !f_hdr.f_symptr)
return 0;
if ((new_ = open (new_name, O_RDWR)) < 0)
{
PERROR (new_name);
return -1;
}
lseek (new_, f_hdr.f_symptr, SEEK_SET);
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, SEEK_CUR);
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, SEEK_CUR);
write (new_, &auxentry, AUXESZ);
}
}
}
close (new_);
return 0;
}
static int
unrelocate_symbols (int new_, int a_out, char *a_name, char *new_name)
{
int i;
LDHDR ldhdr;
LDREL ldrel;
ulong t_reloc = (ulong) &_text - f_ohdr.text_start;
ulong d_reloc = (ulong) &_data - f_ohdr.data_start;
int * p;
if (load_scnptr == 0)
return 0;
lseek (a_out, orig_load_scnptr, SEEK_SET);
if (read (a_out, &ldhdr, sizeof (ldhdr)) != sizeof (ldhdr))
{
PERROR (new_name);
}
#define SYMNDX_TEXT 0
#define SYMNDX_DATA 1
#define SYMNDX_BSS 2
for (i = 0; i < ldhdr.l_nreloc; i++)
{
lseek (a_out,
orig_load_scnptr + LDHDRSZ + LDSYMSZ*ldhdr.l_nsyms + LDRELSZ*i,
SEEK_SET);
if (read (a_out, &ldrel, LDRELSZ) != LDRELSZ)
{
PERROR (a_name);
}
/* 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,
SEEK_SET);
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),
SEEK_SET);
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),
SEEK_SET);
if (write (new_, (void *) &orig_int, sizeof (orig_int))
!= sizeof (orig_int))
{
PERROR (new_name);
}
}
}
}
return 0;
}