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Reduce Mach-o headers

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modified:   p_mach.cpp
This commit is contained in:
John Reiser 2016-10-06 16:06:24 -07:00
parent 82d9bb8f51
commit 42206364e5
1 changed files with 32 additions and 12 deletions
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44
src/p_mach.cpp
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@ -599,6 +599,8 @@ void PackMachBase<T>::pack4(OutputFile *fo, Filter &ft) // append PackHeader
Mach_header *const mhp = (Mach_header *)upxstub;
char *tail = (char *)(1+ mhp);
Mach_segment_command *segtxt = 0; // in temp for output
Mach_section_command *sectxt = 0; // in temp for output
char *const lcp_end = mhdro.sizeofcmds + tail;
Mach_command *lcp = (Mach_command *)(1+ mhp);
Mach_command *lcp_next;
@ -616,22 +618,38 @@ void PackMachBase<T>::pack4(OutputFile *fo, Filter &ft) // append PackHeader
case Mach_segment_command::LC_SEGMENT_64: {
Mach_segment_command *const segptr = (Mach_segment_command *)lcp;
if (!strcmp("__TEXT", segptr->segname)) {
if (0) { // Why is codesign unhappy with this?
int const d = (-1+ segptr->nsects) * sizeof(secTEXT);
if (0 < d) {
segptr->nsects = 1;
segptr->cmdsize -= d;
sz_cmd -= d;
segtxt = segptr; // remember base for appending
sectxt = (Mach_section_command *)(1+ segptr);
// Collapse into 1 section by appending onto the first section.
unsigned off_hi = sectxt->size + sectxt->offset;
Mach_section_command const *scpk = 1+ sectxt;
for (unsigned k = 1; k < segptr->nsects; ++scpk, ++k) {
if (off_hi == scpk->offset) {
off_hi += scpk->size;
sectxt->size += scpk->size;
}
else {
printWarn(fi->getName(), "Unexpected .text section %s\n", (char const *)&scpk->sectname);
// Assume the maximum size: to end of the page.
sectxt->size = (segptr->vmsize + segptr->vmaddr) - sectxt->addr;
break;
}
}
Mach_section_command *const secptr = (Mach_section_command *)(1+ segptr);
int const d = (-1+ segptr->nsects) * sizeof(secTEXT);
if (0 < d) {
segptr->nsects = 1;
sz_cmd -= d;
segptr->cmdsize -= d;
mhp->sizeofcmds -= d;
}
if (Mach_header::CPU_TYPE_I386 == my_cputype) {
// Avoid overlap by moving to va_hi.
upx_uint64_t const delt2 = segTEXT.vmaddr - segptr->vmaddr;
segptr->vmaddr += delt2;
secptr->addr += delt2;
sectxt->addr += delt2;
}
memcpy(&segTEXT, segptr, sizeof(segTEXT));
memcpy(&secTEXT, secptr, sizeof(secTEXT));
memcpy(&secTEXT, sectxt, sizeof(secTEXT));
break;
}
if (!strcmp("__DATA", segptr->segname) && !segptr->vmsize) {
@ -643,13 +661,15 @@ void PackMachBase<T>::pack4(OutputFile *fo, Filter &ft) // append PackHeader
segXHDR.filesize = offLINK - segTEXT.filesize; // XXX FIXME: assumes no __DATA in stub;
segXHDR.maxprot = Mach_segment_command::VM_PROT_READ;
segXHDR.nsects = 0;
if (1) { // replace __DATA with segXHDR
if (0) { // replace __DATA with segXHDR
memcpy(tail, &segXHDR, sizeof(segXHDR));
tail += sizeof(segXHDR);
goto next;
}
else {
// FIXME: no need for LC_SEGMENT; just append to segTEXT and secTEXT
else { // append to .text
segtxt->vmsize = offLINK;
segtxt->filesize = offLINK;
sectxt->size = offLINK - (~PAGE_MASK & sectxt->offset);
skip = 1;
}
}