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Make sure we only touch exactly one page. Update comments.

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committer: mfx <mfx> 1139928961 +0000
This commit is contained in:
Markus F.X.J. Oberhumer 2006-02-14 14:56:01 +00:00
parent 5aa8486265
commit cc4ef1944d
1 changed files with 16 additions and 9 deletions
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25
src/p_w32pe.cpp
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@ -1906,27 +1906,34 @@ void PackW32Pe::pack(OutputFile *fo)
}
if (use_dep_hack)
{
// this works around a "protection" introduced in MSVCRT80
// the protection works like this:
// when the compiler detects that it would link in some code from its
// c runtime library which references some data in a read only
// This works around a "protection" introduced in MSVCRT80, which
// works like this:
// When the compiler detects that it would link in some code from its
// C runtime library which references some data in a read only
// section then it compiles in a runtime check whether that data is
// still in a read only section by looking at the pe header of the
// file. if this check fails the runtime does "interesting" things:
// file. If this check fails the runtime does "interesting" things
// like not running the floating point initialization code - the result
// is an R6002 runtime error.
// these supposed to be read only addresses are covered by the section
// These supposed to be read only addresses are covered by the section
// UPX0 in the compressed files, so we have to patch the PE header
// in the memory. the page on which the PE header is stored is read
// only so we must make it rw, fix the flag up (this is
// PEFL_WRITE of osection[0].flags), make it ro again
// in the memory. And the page on which the PE header is stored is read
// only so we must make it rw, fix the flag (i.e. clear
// PEFL_WRITE of osection[0].flags), and make it ro again.
// rva of the most significant byte of member "flags" in section "UPX0"
const unsigned swri = pe_offset + sizeof(oh) + sizeof(pe_section_t) - 1;
#if 0
if (swri >= 0x1000)
throwCantPack("swri >= 0x1000! Send a bug report please!");
patch_le32(loader, codesize, "SWRI", swri);
patch_le32(loader, codesize, "IMGB", 0u - rvamin);
#else
// make sure we only touch exactly one page
const unsigned addr = 0u - rvamin + swri;
patch_le32(loader, codesize, "SWRI", addr & 0xfff); // page offset
patch_le32(loader, codesize, "IMGB", addr &~ 0xfff); // page mask
#endif
patch_le32(loader, codesize, "VPRO", myimport + get_le32(oimpdlls + 16) + 8);
}
if (big_relocs & 6)