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Code Issues Releases Wiki Activity

MachO no longer needs contiguous LC_SEGMENT (SourceForge bug 3308161)

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This commit is contained in:
John Reiser 2012-10-10 08:51:52 -07:00
parent f890f6bb09
commit d442c58fd1
3 changed files with 64 additions and 15 deletions
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63
src/p_lx_elf.cpp
View File

@ -85,6 +85,52 @@ fpad4(OutputFile *fo)
return d + len;
}
void
PackLinuxElf32::hemfix(Elf32_Phdr *phdr, unsigned n_phdr)
{
unsigned j;
for (j=0; j < n_phdr; ++phdr, ++j) {
unsigned const mask = -phdr->p_align;
if (PT_LOAD32==phdr->p_type) { /* first PT_LOAD */
if (~mask & phdr->p_vaddr
&& 0==(~mask & (phdr->p_vaddr - phdr->p_offset))) {
unsigned const hem = ~mask & phdr->p_offset;
phdr->p_offset -= hem;
phdr->p_vaddr -= hem;
if (phdr->p_paddr)
phdr->p_paddr -= hem;
phdr->p_filesz += hem;
phdr->p_memsz += hem;
}
break;
}
}
return;
}
void
PackLinuxElf64::hemfix(Elf64_Phdr *phdr, unsigned n_phdr)
{
unsigned j;
for (j=0; j < n_phdr; ++phdr, ++j) {
unsigned const mask = -phdr->p_align;
if (PT_LOAD64==phdr->p_type) { /* first PT_LOAD */
if (~mask & phdr->p_vaddr
&& 0==(~mask & (phdr->p_vaddr - phdr->p_offset))) {
unsigned const hem = ~mask & phdr->p_offset;
phdr->p_offset -= hem;
phdr->p_vaddr -= hem;
if (phdr->p_paddr)
phdr->p_paddr -= hem;
phdr->p_filesz += hem;
phdr->p_memsz += hem;
}
break;
}
}
return;
}
int
PackLinuxElf32::checkEhdr(Elf32_Ehdr const *ehdr) const
{
@ -1240,7 +1286,8 @@ bool PackLinuxElf32::canPack()
unsigned osabi0 = u.buf[Elf32_Ehdr::EI_OSABI];
// The first PT_LOAD32 must cover the beginning of the file (0==p_offset).
Elf32_Phdr const *phdr = (Elf32_Phdr const *)(u.buf + e_phoff);
Elf32_Phdr *phdr = (Elf32_Phdr *)(u.buf + e_phoff);
hemfix(phdr, umin(14, e_phnum));
note_size = 0;
for (unsigned j=0; j < e_phnum; ++phdr, ++j) {
if (j >= 14) {
@ -1476,16 +1523,16 @@ PackLinuxElf64amd::canPack()
}
// The first PT_LOAD64 must cover the beginning of the file (0==p_offset).
Elf64_Phdr const *phdr = (Elf64_Phdr const *)(u.buf + (unsigned) e_phoff);
Elf64_Phdr *phdr = (Elf64_Phdr *)(u.buf + e_phoff);
hemfix(phdr, umin(14, e_phnum));
for (unsigned j=0; j < e_phnum; ++phdr, ++j) {
if (j >= 14)
return false;
if (phdr->PT_LOAD64 == get_te32(&phdr->p_type)) {
// Just avoid the "rewind" when unpacking?
//if (phdr->p_offset != 0) {
// throwCantPack("invalid Phdr p_offset; try '--force-execve'");
// return false;
//}
if (phdr->p_offset != 0) {
throwCantPack("invalid Phdr p_offset; try '--force-execve'");
return false;
}
load_va = get_te64(&phdr->p_vaddr);
exetype = 1;
break;
@ -1974,6 +2021,7 @@ void PackLinuxElf32::pack1(OutputFile *fo, Filter & /*ft*/)
phdri = new Elf32_Phdr[e_phnum];
fi->seek(e_phoff, SEEK_SET);
fi->readx(phdri, sz_phdrs);
hemfix(phdri, e_phnum);
// Remember all PT_NOTE, and find lg2_page from PT_LOAD.
Elf32_Phdr const *phdr = phdri;
@ -2163,6 +2211,7 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
phdri = new Elf64_Phdr[e_phnum];
fi->seek(e_phoff, SEEK_SET);
fi->readx(phdri, sz_phdrs);
hemfix(phdri, e_phnum);
Elf64_Phdr const *phdr = phdri;
note_size = 0;

2
src/p_lx_elf.h
View File

@ -101,6 +101,7 @@ public:
PackLinuxElf32(InputFile *f);
virtual ~PackLinuxElf32();
protected:
void hemfix(Elf32_Phdr *phdr, unsigned n_phdr);
virtual int checkEhdr(Elf32_Ehdr const *ehdr) const;
virtual bool canPack();
@ -225,6 +226,7 @@ public:
/*virtual void buildLoader(const Filter *);*/
protected:
void hemfix(Elf64_Phdr *phdr, unsigned n_phdr);
virtual int checkEhdr(Elf64_Ehdr const *ehdr) const;
virtual void pack1(OutputFile *, Filter &); // generate executable header

14
src/p_mach.cpp
View File

@ -1376,7 +1376,7 @@ bool PackMachBase<T>::canPack()
// Put LC_SEGMENT together at the beginning, ascending by .vmaddr.
qsort(msegcmd, ncmds, sizeof(*msegcmd), compare_segment_command);
// Check that LC_SEGMENTs form one contiguous chunk of the file.
// Check alignment of non-null LC_SEGMENT.
for (unsigned j= 0; j < ncmds; ++j) {
if (lc_seg==msegcmd[j].cmd) {
if (~PAGE_MASK & (msegcmd[j].fileoff | msegcmd[j].vmaddr)) {
@ -1384,13 +1384,11 @@ bool PackMachBase<T>::canPack()
}
if (msegcmd[j].vmsize==0)
break; // was sorted last
if (0 < j) {
unsigned const sz = PAGE_MASK
& (~PAGE_MASK + msegcmd[j-1].filesize);
if ((sz + msegcmd[j-1].fileoff)!=msegcmd[j].fileoff) {
return false;
}
}
// We used to check that LC_SEGMENTS were contiguous,
// but apparently that is not needed anymore,
// and Google compilers generate strange layouts.
++n_segment;
sz_segment = msegcmd[j].filesize + msegcmd[j].fileoff - msegcmd[0].fileoff;
}