/* Rebase r_address in the relocation table. */
static void
rebase_reloc_address (off_t reloff, int nrel, long linkedit_delta, long diff)
{
int i;
struct relocation_info reloc_info;
struct scattered_relocation_info *sc_reloc_info
= (struct scattered_relocation_info *) &reloc_info;
for (i = 0; i < nrel; i++, reloff += sizeof (reloc_info))
{
if (lseek (infd, reloff - linkedit_delta, L_SET)
!= reloff - linkedit_delta)
unexec_error ("rebase_reloc_table: cannot seek to reloc_info");
if (!unexec_read (&reloc_info, sizeof (reloc_info)))
unexec_error ("rebase_reloc_table: cannot read reloc_info");
if (sc_reloc_info->r_scattered == 0
&& reloc_info.r_type == GENERIC_RELOC_VANILLA)
{
reloc_info.r_address -= diff;
if (!unexec_write (reloff, &reloc_info, sizeof (reloc_info)))
unexec_error ("rebase_reloc_table: cannot write reloc_info");
}
}
}
/* Fix up relocation entries. */
static void
unrelocate (const char *name, off_t reloff, int nrel, vm_address_t base)
{
int i, unreloc_count;
struct relocation_info reloc_info;
struct scattered_relocation_info *sc_reloc_info
= (struct scattered_relocation_info *) &reloc_info;
vm_address_t location;
for (unreloc_count = 0, i = 0; i < nrel; i++)
{
if (lseek (infd, reloff, L_SET) != reloff)
unexec_error ("unrelocate: %s:%d cannot seek to reloc_info", name, i);
if (!unexec_read (&reloc_info, sizeof (reloc_info)))
unexec_error ("unrelocate: %s:%d cannot read reloc_info", name, i);
reloff += sizeof (reloc_info);
if (sc_reloc_info->r_scattered == 0)
switch (reloc_info.r_type)
{
case GENERIC_RELOC_VANILLA:
location = base + reloc_info.r_address;
if (location >= data_segment_scp->vmaddr
&& location < (data_segment_scp->vmaddr
+ data_segment_scp->vmsize))
{
off_t src_off = data_segment_old_fileoff
+ (location - data_segment_scp->vmaddr);
off_t dst_off = data_segment_scp->fileoff
+ (location - data_segment_scp->vmaddr);
if (!unexec_copy (dst_off, src_off, 1 << reloc_info.r_length))
unexec_error ("unrelocate: %s:%d cannot copy original value",
name, i);
unreloc_count++;
}
break;
default:
unexec_error ("unrelocate: %s:%d cannot handle type = %d",
name, i, reloc_info.r_type);
}
else
switch (sc_reloc_info->r_type)
{
#if defined (__ppc__)
case PPC_RELOC_PB_LA_PTR:
/* nothing to do for prebound lazy pointer */
break;
#endif
default:
unexec_error ("unrelocate: %s:%d cannot handle scattered type = %d",
name, i, sc_reloc_info->r_type);
}
}
if (nrel > 0)
printf ("Fixed up %d/%d %s relocation entries in data segment.\n",
unreloc_count, nrel, name);
}
static void
unexec_copy (int new_fd, int old_fd, long old_pos, long new_pos, int bytes)
{
int remains = bytes;
char buf[128];
while (remains > 0)
{
int n_to_copy = remains > sizeof(buf) ? sizeof(buf) : remains;
unexec_read (old_fd, old_pos, buf, n_to_copy);
unexec_write (new_fd, new_pos, buf, n_to_copy);
old_pos += n_to_copy;
new_pos += n_to_copy;
remains -= n_to_copy;
}
return;
}
/* Read header and load commands from input file. Store the latter in
the global array lca. Store the total number of load commands in
global variable nlc. */
static void
read_load_commands (void)
{
int i;
if (!unexec_read (&mh, sizeof (struct mach_header)))
unexec_error ("cannot read mach-o header");
if (mh.magic != MH_MAGIC)
unexec_error ("input file not in Mach-O format");
if (mh.filetype != MH_EXECUTE)
unexec_error ("input Mach-O file is not an executable object file");
#if VERBOSE
printf ("--- Header Information ---\n");
printf ("Magic = 0x%08x\n", mh.magic);
printf ("CPUType = %d\n", mh.cputype);
printf ("CPUSubType = %d\n", mh.cpusubtype);
printf ("FileType = 0x%x\n", mh.filetype);
printf ("NCmds = %d\n", mh.ncmds);
printf ("SizeOfCmds = %d\n", mh.sizeofcmds);
printf ("Flags = 0x%08x\n", mh.flags);
#endif
nlc = mh.ncmds;
lca = malloc (nlc * sizeof *lca);
for (i = 0; i < nlc; i++)
{
struct load_command lc;
/* Load commands are variable-size: so read the command type and
size first and then read the rest. */
if (!unexec_read (&lc, sizeof (struct load_command)))
unexec_error ("cannot read load command");
lca[i] = malloc (lc.cmdsize);
memcpy (lca[i], &lc, sizeof (struct load_command));
if (!unexec_read (lca[i] + 1, lc.cmdsize - sizeof (struct load_command)))
unexec_error ("cannot read content of load command");
if (lc.cmd == LC_SEGMENT)
{
struct segment_command *scp = (struct segment_command *) lca[i];
if (scp->vmaddr + scp->vmsize > infile_lc_highest_addr)
infile_lc_highest_addr = scp->vmaddr + scp->vmsize;
if (strncmp (scp->segname, SEG_TEXT, 16) == 0)
{
struct section *sectp = (struct section *) (scp + 1);
int j;
for (j = 0; j < scp->nsects; j++)
if (sectp->offset < text_seg_lowest_offset)
text_seg_lowest_offset = sectp->offset;
}
}
}
printf ("Highest address of load commands in input file: %#8lx\n",
(unsigned long)infile_lc_highest_addr);
printf ("Lowest offset of all sections in __TEXT segment: %#8lx\n",
text_seg_lowest_offset);
printf ("--- List of Load Commands in Input File ---\n");
printf ("# cmd cmdsize name address size\n");
for (i = 0; i < nlc; i++)
{
printf ("%1d ", i);
print_load_command (lca[i]);
}
}
int
unexec (char *new_name, char *old_name,
unsigned int emacs_edata, unsigned int dummy1, unsigned int dummy2)
{
/* /dld.sl data */
struct dynamic *ld = 0;
/* old and new state */
int old_fd;
int new_fd;
struct exec old_hdr;
struct exec new_hdr;
struct stat old_buf;
/* some process specific "constants" */
unsigned long n_pagsiz;
caddr_t dynamic_beg;
caddr_t current_break = (caddr_t) sbrk (0);
/* dynamically linked image? -- if so, find dld.sl structures */
if (dynamic_addr)
{
ld = (struct dynamic *) dynamic_addr;
#ifdef DEBUG
printf ("dl_text = %#x\n", ld->text);
printf ("dl_data = %#x\n", ld->data);
printf ("dl_bss = %#x\n", ld->bss);
printf ("dl_end = %#x\n", ld->end);
printf ("dl_dmodule = %#x\n", ld->dmodule);
printf ("dl_dlt = %#x\n", ld->dlt);
printf ("dl_plt = %#x\n", ld->plt);
#endif
}
/* open the old and new files, figuring out how big the old one is
so that we can map it in */
old_fd = unexec_open (old_name, O_RDONLY, 0);
new_fd = unexec_open (new_name, O_RDWR | O_CREAT | O_TRUNC, 0666);
/* setup the header and the statbuf for old_fd */
unexec_read (old_fd, 0, (char *) &old_hdr, sizeof (old_hdr));
unexec_fstat (old_fd, &old_buf);
/* set up some important constants */
n_pagsiz = EXEC_PAGESIZE;
/* setup beginning of data to copy from executable */
if (ld)
dynamic_beg = ld->dmodule;
else
dynamic_beg = (caddr_t)EXEC_ALIGN (old_hdr.a_text) + old_hdr.a_data;
/* set up the new exec */
new_hdr = old_hdr;
new_hdr.a_text = MASK_DOWN (emacs_edata, n_pagsiz);
new_hdr.a_data = MASK_UP (current_break, n_pagsiz)
- EXEC_ALIGN(new_hdr.a_text);
new_hdr.a_bss = 0;
#ifdef DEBUG
printf ("old text %#x\n", old_hdr.a_text);
printf ("new text %#x\n", new_hdr.a_text);
printf ("old data %#x\n", old_hdr.a_data);
printf ("new data %#x\n", new_hdr.a_data);
printf ("old bss %#x\n", old_hdr.a_bss);
printf ("new bss %#x\n", new_hdr.a_bss);
#endif
/* set up this variable, in case we want to reset "the break"
when restarting */
sbrk_of_0_at_unexec = ((unsigned long) MASK_UP (current_break, n_pagsiz));
/* Write out the first approximation to the new file. The sizes of
each section will be correct, but there will be a number of
corrections that will need to be made. */
{
long old_datoff = DATA_OFFSET (old_hdr);
long new_datoff = DATA_OFFSET (new_hdr);
long old_dataddr = EXEC_ALIGN (old_hdr.a_text);
long new_dataddr = EXEC_ALIGN (new_hdr.a_text);
long new_mcaloff = MODCAL_OFFSET (new_hdr);
long old_mcaloff = MODCAL_OFFSET (old_hdr);
long newtext_size = new_hdr.a_text - old_dataddr;
long newdata1_size = (unsigned long)dynamic_beg - new_dataddr;
long dyn_size = (EXEC_ALIGN (old_hdr.a_text) + old_hdr.a_data)
- (unsigned long)dynamic_beg;
long newdata2_size = (unsigned long)current_break
- ((unsigned long)dynamic_beg + dyn_size);
long pad_size =
MASK_UP (current_break, n_pagsiz) - ((unsigned long) current_break);
#ifdef DEBUG
printf ("current break is %#lx\n", current_break);
printf ("old_dataddr = %#lx, dynamic_beg = %#lx\n",
old_dataddr, dynamic_beg);
#endif
/*
* First, write the text segment with new header -- copy
* everything until the start of the data segment from the old
* file
*/
#ifdef DEBUG
printf ("copying %#lx bytes of text from 0\n", old_datoff);
#endif
unexec_copy (new_fd, old_fd, 0, 0, old_datoff);
/* pad out the text segment */
#ifdef DEBUG
printf ( "text pad size is %#x\n", old_dataddr - old_hdr.a_text);
#endif
unexec_pad (new_fd, old_dataddr - old_hdr.a_text);
/*
* Update debug header spoo
*/
if (new_hdr.a_extension > 0)
{
new_hdr.a_extension += LESYM_OFFSET(new_hdr) - LESYM_OFFSET(old_hdr);
}
/*
* go back and write the new header.
*/
unexec_write (new_fd, 0, (char *) &new_hdr, sizeof (new_hdr));
/*
* Copy the part of the data segment which becomes text from the
* running image.
*/
#ifdef DEBUG
printf ("copying %#lx bytes of new text from %#lx to position %#lx\n",
newtext_size, old_dataddr, TEXT_OFFSET(new_hdr) + old_dataddr);
#endif
unexec_write (new_fd, TEXT_OFFSET(new_hdr) + old_dataddr,
(caddr_t)old_dataddr, newtext_size);
#ifdef DEBUG
printf ("new DATA_OFFSET is %#lx\n", new_datoff);
#endif
/*
* Copy the part of the old data segment which will be data
* in the new executable (before the dynamic stuff)
* from the running image.
*/
#ifdef DEBUG
printf ("copying %#lx bytes of data from %#lx to position %#lx\n",
newdata1_size, new_dataddr, new_datoff);
#endif
unexec_write (new_fd, new_datoff, (caddr_t)new_dataddr, newdata1_size);
/* copy the dynamic part of the data segment from the old executable */
if (dyn_size)
{
#ifdef DEBUG
printf ("copying %#lx bytes of dyn data from executable"
" at address %#lx to position %#lx\n",
dyn_size, dynamic_beg, new_datoff + newdata1_size);
#endif
unexec_copy (new_fd, old_fd, old_datoff + newtext_size + newdata1_size,
new_datoff + newdata1_size, dyn_size);
}
/* copy remaining data (old bss) from the running image */
#ifdef DEBUG
printf ("copying %#lx bytes of data from %#lx to position %#lx\n",
newdata2_size, new_dataddr + newdata1_size + dyn_size,
new_datoff + newdata1_size + dyn_size);
#endif
unexec_write (new_fd, new_datoff + newdata1_size + dyn_size,
(caddr_t)(new_dataddr + newdata1_size + dyn_size),
newdata2_size);
/* pad out the data segment */
#ifdef DEBUG
printf ( "pad size is %#x\n", pad_size);
#endif
unexec_pad (new_fd, pad_size);
/* Finally, copy the rest of the junk from the old file. */
#ifdef DEBUG
printf ("Copying %#lx bytes of junk from %#lx (old) to %#lx (new)\n",
old_buf.st_size - old_mcaloff, old_mcaloff, new_mcaloff);
#endif
unexec_copy (new_fd, old_fd, old_mcaloff, new_mcaloff,
old_buf.st_size - old_mcaloff);
{
long curpos, offset;
struct _debug_header dhdr;
int new_header_delta;
new_header_delta = LESYM_OFFSET(new_hdr) - LESYM_OFFSET(old_hdr);
if ((new_header_delta > 0) &&
((offset = EXT_OFFSET(old_hdr)) > 0))
{
curpos = lseek(new_fd, 0, SEEK_CUR);
lseek(old_fd, offset, 0);
if (read(old_fd, &dhdr, sizeof(dhdr)) == sizeof(dhdr))
{
dhdr.header_offset += new_header_delta;
dhdr.gntt_offset += new_header_delta;
dhdr.lntt_offset += new_header_delta;
dhdr.slt_offset += new_header_delta;
dhdr.vt_offset += new_header_delta;
dhdr.xt_offset += new_header_delta;
lseek(new_fd, EXT_OFFSET(new_hdr), SEEK_SET);
if (write(new_fd, &dhdr, sizeof(dhdr)) != sizeof(dhdr))
{
unexec_error("Unable to write debug information to \"%s\"\n",
1, new_name);
}
lseek(new_fd, curpos, SEEK_SET);
}
else
{
unexec_error("Unable to read debug information from \"%s\"\n",
1, old_name);
}
}
}
}
/* make the output file executable -- then quit */
unexec_fchmod (new_fd, 0755);
close (old_fd);
close (new_fd);
return 0;
}
