mirror of https://github.com/Shizmob/smol
113 lines
2.9 KiB
NASM
113 lines
2.9 KiB
NASM
; vim: set ft=nasm:
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%include "linkscr.inc"
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[section .header]
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%include "elf.inc"
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global _EHDR
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_EHDR:
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ehdr:
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; e_ident
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db 0x7F, "ELF"
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db EI_CLASS, EI_DATA, EI_VERSION, EI_OSABI
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db EI_OSABIVERSION
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times 7 db 0 ; EI_PAD, ld.so is a busta and won't let us use our leet
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; group tags for padding bytes :(
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dw ELF_TYPE ; e_type: 2 = executable
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dw ELF_MACHINE ; e_machine: 3 = x86
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dd EI_VERSION ; e_version
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dd _smol_start ; e_entry
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dd (phdr - ehdr) ; e_phoff
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dd 0 ; e_shoff
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dd 0 ; e_flags
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dw (phdr - ehdr) ; e_ehsize
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dw (phdr.load - phdr.dynamic) ; e_phentsize
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%ifdef USE_NX
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%error "USE_NX not supported yet on i386 ('GOT' still needs RWX, and alignment has to be fixed)"
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;%ifdef USE_INTERP
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; dw 4, 0 ; e_phnum, e_shentsize
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;%else
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; dw 3, 0
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;%endif
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;.segments:
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;.segments.load.text:
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; dd PT_LOAD
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; dd _smol_origin
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; dd _smol_text_start, 0
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; dd _smol_textandheader_size
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; dd _smol_textandheader_size
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; dd (PHDR_R | PHDR_X)
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; dd 0x1000
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;.segments.load.data:
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; dd PT_LOAD
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; dd _smol_data_off
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; dd _smol_data_start, 0
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; dd _smol_data_size
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; dd _smol_dataandbss_size
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; dd (PHDR_R | PHDR_W)
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; dd 0x1;000
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%else
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global _PHDR
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_PHDR:
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phdr:
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%endif
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%ifdef USE_INTERP
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phdr.interp:
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dd PT_INTERP ; {e_phnum: 2, e_shentsize: 0}, p_type
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dd (interp - ehdr) ; {e_shnum: <junk>, e_shstrnd: <junk>}, p_offset
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dd interp, interp ; p_vaddr, p_paddr
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dd (interp.end-interp); p_filesz
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dd (interp.end-interp); p_memsz
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dd 0,0 ; p_flags, p_align
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%endif
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phdr.dynamic:
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dd PT_DYNAMIC ; {e_phnum: 2, e_shentsize: 0}, p_type
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dd (dynamic - ehdr) ; {e_shnum: <junk>, e_shstrnd: <junk>}, p_offset
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dd dynamic, 0 ; p_vaddr, p_paddr
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dd (dynamic.end - dynamic) ; p_filesz
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dd (dynamic.end - dynamic) ; p_memsz
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dd 0, 0 ; p_flags, p_align
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%ifndef USE_NX
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phdr.load:
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dd PT_LOAD ; p_type: 1 = PT_LOAD
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dd 0 ; p_offset
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dd ehdr, 0 ; p_vaddr, p_paddr
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;; use memsize twice here, linux doesn't care and it compresses better
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; actually, linux doesn't care, but the hardware does >__>
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dd _smol_total_filesize ; p_filesz
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dd _smol_total_memsize ; p_memsz
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dd (PHDR_R | PHDR_W | PHDR_X) ; p_flags
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dd 0x1000 ; p_align
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%endif
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phdr.end:
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%ifdef USE_INTERP
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[section .rodata.interp]
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global _INTERP
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_INTERP:
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interp:
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db "/lib/ld-linux.so.2",0
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interp.end:
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%endif
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[section .rodata.dynamic]
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global _DYNAMIC
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_DYNAMIC:
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dynamic:
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dynamic.strtab:
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dd DT_STRTAB ; d_tag
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dd _strtab ; d_un.d_ptr
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dynamic.symtab:
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; this is required to be present or ld.so will crash, but it can be bogus
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dd DT_SYMTAB ; d_tag: 6 = DT_SYMTAB
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dd 0 ; d_un.d_ptr
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%ifdef USE_DT_DEBUG
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dynamic.debug:
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dd DT_DEBUG
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_DEBUG:
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dd 0
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%endif
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