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Code to supply a "linking view" for /usr/bin/strip.

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(Not used today because yet another bug is worse.)  See
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=81644

committer: jreiser <jreiser> 1042341933 +0000
This commit is contained in:
John Reiser 2003-01-12 03:25:33 +00:00
parent 73dc4eede0
commit 4e0967e0a1
1 changed files with 53 additions and 1 deletions
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54
src/p_lx_exc.cpp
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@ -152,7 +152,59 @@ PackLinuxI386::pack4(OutputFile *fo, Filter &ft)
((elfout.ehdr.e_phnum==3) ? elfout.phdr[2].p_memsz : 0) ;
super::pack4(fo, ft); // write PackHeader and overlay_offset
elfout.phdr[0].p_filesz = fo->getBytesWritten();
unsigned eod = fo->getBytesWritten();
elfout.phdr[0].p_filesz = eod;
#if 0 // {
// /usr/bin/strip from RedHat 8.0 (binutils-2.13.90.0.2-2)
// generates a 92-byte [only] output, because the "linking view"
// is empty. This code supplies a "linking view".
// However, 'strip' then generates _plausible_ junk that gets
// "Illegal instruction" because 'strip' changes p_hdr[1].p_align,
// .p_offset, and .p_vaddr incorrectly. So the "cure" is worse than
// the disease. It is obvious that a 92-byte file is bad,
// but it is not obvious that the changed .p_align is bad.
// Also, having a totally empty "linking view" is easier for 'strip'
// to fix: just detect that, and do nothing.
// So, we don't use this code for now [2003-01-11].
// Supply a "linking view" that covers everything,
// so that 'strip' does not omit everything.
Elf_LE32_Shdr shdr;
// The section header string table.
char const shstrtab[] = "\0.\0.shstrtab";
set_native32(&elfout.ehdr.e_shoff, eod);
set_native16(&elfout.ehdr.e_shentsize, sizeof(shdr));
set_native16(&elfout.ehdr.e_shnum, 3);
set_native16(&elfout.ehdr.e_shstrndx, 2);
// An empty Elf32_Shdr for space as a null index.
memset(&shdr, 0, sizeof(shdr));
set_native32(&shdr.sh_type, Elf_LE32_Shdr::SHT_NULL);
fo->write(&shdr, sizeof(shdr));
// Cover all the bits we need at runtime.
memset(&shdr, 0, sizeof(shdr));
set_native32(&shdr.sh_name, 1);
set_native32(&shdr.sh_type, Elf_LE32_Shdr::SHT_PROGBITS);
set_native32(&shdr.sh_flags, Elf_LE32_Shdr::SHF_ALLOC);
set_native32(&shdr.sh_addr, elfout.phdr[0].p_vaddr);
set_native32(&shdr.sh_offset, overlay_offset);
set_native32(&shdr.sh_size, eod - overlay_offset);
set_native32(&shdr.sh_addralign, 4096);
fo->write(&shdr, sizeof(shdr));
// A section header for the section header string table.
memset(&shdr, 0, sizeof(shdr));
set_native32(&shdr.sh_name, 3);
set_native32(&shdr.sh_type, Elf_LE32_Shdr::SHT_STRTAB);
set_native32(&shdr.sh_offset, 3*sizeof(shdr) + eod);
set_native32(&shdr.sh_size, sizeof(shstrtab));
fo->write(&shdr, sizeof(shdr));
fo->write(shstrtab, sizeof(shstrtab));
#endif // }
#define PAGE_MASK (~0<<12)
// pre-calculate for benefit of runtime disappearing act via munmap()