{simple,shoddy,smart} minsize-oriented linker
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import sys
from smolshared import *
def output_x86(libraries, outf):
outf.write('; vim: set ft=nasm:\n') # be friendly
outf.write('bits 32\n')
shorts = { l: l.split('.', 1)[0].lower().replace('-', '_') for l in libraries }
outf.write('%include "header32.asm"\n')
outf.write('.dynamic.needed:\n')
for library in libraries:
outf.write('dd 1;DT_NEEDED\n')
outf.write('dd (_symbols.{} - _symbols)\n'.format(shorts[library]))
outf.write('.dynamic.end:\n')
# if needgot:
# outf.write('global _GLOBAL_OFFSET_TABLE_\n')
# outf.write('_GLOBAL_OFFSET_TABLE_:\n')
# outf.write('dd dynamic\n')
outf.write('_symbols:\n')
for library, symrels in libraries.items():
outf.write('\t_symbols.{}: db "{}",0\n'.format(shorts[library], library))
for sym, reloc in symrels:
# meh
if reloc != 'R_386_PC32':
eprintf('Relocation type ' + reloc + ' of symbol ' + sym + ' unsupported!')
sys.exit(1)
hash = hash_djb2(sym)
outf.write("""
\t\tglobal {name}
\t\t{name}: db 0xE9
\t\t dd 0x{hash:x}
""".format(name=sym, hash=hash).lstrip('\n'))
outf.write('\tdb 0\n') # TODO: not a dd?
outf.write('db 0\n')
outf.write('_symbols.end:\n')
outf.write('%include "loader32.asm"\n')
def output_amd64(libraries, outf):
outf.write('; vim: set ft=nasm:\n')
outf.write('bits 64\n')
shorts = { l: l.split('.', 1)[0].lower().replace('-', '_') for l in libraries }
outf.write('%include "header64.asm"\n')
outf.write('dynamic.needed:\n')
for library in libraries:
outf.write('dq 1;DT_NEEDED\n')
outf.write('dq (_symbols.{} - _symbols)\n'.format(shorts[library]))
outf.write('dynamic.end:\n')
outf.write('[section .data.smolgot]\n')
# if needgot:
# outf.write('global _GLOBAL_OFFSET_TABLE_\n')
# outf.write('_GLOBAL_OFFSET_TABLE_:\n')
# outf.write('dq dynamic\n')
outf.write('_symbols:\n')
for library, symrels in libraries.items():
outf.write('\t_symbols.{}: db "{}",0\n'.format(shorts[library], library))
for sym, reloc in symrels:
if reloc != 'R_X86_64_PLT32' and reloc != 'R_X86_64_GOTPCRELX':
eprintf('Relocation type ' + reloc + ' of symbol ' + sym + ' unsupported!')
sys.exit(1)
if reloc == 'R_X86_64_GOTPCRELX':
outf.write("""
global {name}
{name}:
""".format(name=sym).lstrip('\n'))
hash = hash_djb2(sym)
outf.write('\t\t_symbols.{lib}.{name}: dq 0x{hash:x}\n'\
.format(lib=shorts[library],name=sym,hash=hash))
outf.write('\tdq 0\n')
outf.write('db 0\n')
outf.write('_symbols.end:\n')
outf.write('_smolplt:\n')
for library, symrels in libraries.items():
for sym, reloc in symrels:
if reloc == 'R_X86_64_PLT32':
outf.write("""
[section .text.smolplt.{name}]
global {name}
{name}:
jmp [rel _symbols.{lib}.{name}]
""".format(lib=shorts[library],name=sym).lstrip('\n'))
outf.write('_smolplt.end:\n')
outf.write('%include "loader64.asm"\n')
def output(arch, libraries, outf):
if arch == 'i386': output_x86(libraries, outf)
elif arch == 'x86_64': output_amd64(libraries, outf)
else:
eprintf("E: cannot emit for arch '" + str(arch) + "'")
sys.exit(1)