mkELF.py

#!/usr/bin/env python
"""
Reconstitue an ELF file based on the ELF header in the *.b00
file and the data in each of the other files.
"""

import sys, struct, glob, os

def readfmt(f, fmt) :
    d = f.read(struct.calcsize(fmt))
    return struct.unpack(fmt, d)
def writefmt(f, fmt, *args) :
    f.write(struct.pack(fmt, *args))

class EHdr(object) :
    def __init__(self, f) :
        self.e_ident = f.read(16)
        (self.e_type,
                self.e_machine, 
                self.e_version, 
                self.e_entry, 
                self.e_phoff, 
                self.e_shoff, 
                self.e_flags, 
                self.e_ehsize, 
                self.e_phentsize, 
                self.e_phnum,
                self.e_shentsize,
                self.e_shnum,
                self.e_shstrndx) = readfmt(f, '<HHIIIIIHHHHHH')
    def write(self, f) :
        f.write(self.e_ident) 
        writefmt(f, '<HHIIIIIHHHHHH', self.e_type, 
                self.e_machine, 
                self.e_version, 
                self.e_entry, 
                self.e_phoff, 
                self.e_shoff, 
                self.e_flags, 
                self.e_ehsize, 
                self.e_phentsize, 
                self.e_phnum, 
                self.e_shentsize, 
                self.e_shnum, 
                self.e_shstrndx)

class PHdr(object) :
    def __init__(self, f) :
        (self.p_type,
            self.p_offset,
            self.p_vaddr,
            self.p_paddr,
            self.p_filesz,
            self.p_memsz,
            self.p_flags,
            self.p_align) = readfmt(f, "IIIIIIII")
    def write(self, f) :
        return writefmt(f, '<IIIIIIII',
            self.p_type,
            self.p_offset,
            self.p_vaddr,
            self.p_paddr,
            self.p_filesz,
            self.p_memsz,
            self.p_flags,
            self.p_align)

def pr(x, pref) :
    for n in dir(x) :
        if pref == n[:len(pref)] :
            print '%s=%r' % (n, getattr(x, n)),
    print
    
class Error(Exception) :
    pass

def proc(fn) :
    fn0 = '%s.b00' % fn
    b = file(fn0, 'rb')
    hdr = EHdr(b)
    #pr(hdr, 'e_')

    # load in program section headers and filter
    b.seek(hdr.e_phoff)
    #print '%x' % hdr.e_phoff
    phdrs = [PHdr(b) for n in xrange(hdr.e_phnum)]

    ofn = os.path.basename(fn) + '.elf'
    print 'making', ofn
    f = file(ofn, 'wb')
    off = 0
    for n in xrange(len(phdrs)) :
        fnn = '%s.b%02d' % (fn, n)
        p = phdrs[n]
        print '%s -- %x - %x (%x) @ %x' % (fnn, p.p_paddr, p.p_paddr + p.p_memsz, p.p_paddr + p.p_filesz, p.p_vaddr)

        # copy out padding
        pad = p.p_offset - off
        if pad < 0 :
            raise Error("negative padding!")
        f.write('\0' * pad)
        off += pad

        # copy out file
        if p.p_filesz :
            dat = file(fnn, 'rb').read()
            if len(dat) != p.p_filesz :
                raise Error("bad section size")
            f.write(dat)
            off += len(dat)
    f.close()

for arg in sys.argv[1:] :
    proc(arg)