4

All.

Someone created an executable file.

# ldd test_bin 
    libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x4082d000)
    libA.so.0 => /usr/lib/libA.so.0 (0x408fe000)
    libB.so.0 => /usr/lib/libB.so.0 (0x4093e000)
    libgobject-2.0.so.0 => /usr/lib/libgobject-2.0.so.0 (0x409ad000)
    libgthread-2.0.so.0 => /usr/lib/libgthread-2.0.so.0 (0x409fe000)
    librt.so.1 => /lib/librt.so.1 (0x40a0a000)
    libglib-2.0.so.0 => /usr/lib/libglib-2.0.so.0 (0x40a19000)
    libdbus-1.so.3 => /usr/lib/libdbus-1.so.3 (0x40b25000)
    libssl.so.0.9.8 => /usr/lib/libssl.so.0.9.8 (0x40b67000)
    libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x40bb0000)
    libpthread.so.0 => /lib/libpthread.so.0 (0x40bc3000)
    libc.so.6 => /lib/libc.so.6 (0x40be3000)
    libm.so.6 => /lib/libm.so.6 (0x40d11000)
    libcrypto.so.0.9.8 => /usr/lib/libcrypto.so.0.9.8 (0x40d87000)
    /lib/ld-linux.so.3 (0x40000000)
    libgmodule-2.0.so.0 => /usr/lib/libgmodule-2.0.so.0 (0x40f4e000)
    libdl.so.2 => /lib/libdl.so.2 (0x40f59000)

In this case, I want to merge libB.so into libA.so.

So I create libA.so that is covered all APIs provided by libB.so.

Then I have to re-link with this library. But I don't have any source for test_bin.

How can I remove libB.so linking from executable file without any sources?

Is it possible? I just look around binutils. But I haven't found for it.

Please give me an advice.

spbear
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  • By the way, why do you want to eliminate this dependency? – jmpcm Sep 27 '11 at 09:10
  • libB.so's naming is not to my taste.;-) – spbear Sep 27 '11 at 09:24
  • libA.so and libB.so has similar role for its action. But there is some reason for dividing it. (such as permission or policy) It is not applied any more. And I merge it into just 1 library for convenient maintenance. – spbear Sep 27 '11 at 09:27
  • This is almost certainly not the solution you're looking for: but if nothing else, you can manually fix-up the ELF header to produce your desired result. I have a script for this somewhere. – mrduclaw Sep 27 '11 at 09:28
  • Is it needed just fixing-up ELF header? If so, it's great solution for me! – spbear Sep 27 '11 at 09:33

3 Answers3

0

You could go the easy route and make libB.so and libB.so.0 a symlink to libA.so.0. Doesn't modify the executable, but is a quick and portable solution.

thiton
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  • Yes, it works for me. But I want to get more cleared solution. Thank you. – spbear Sep 27 '11 at 09:01
  • @spbear: If you are worried about re-using the name of libB.so, just increment the age and go on with libB.so.1 etc. Otherwise, good luck finding a less hacky version, I'll be watching this discussion :-). – thiton Sep 27 '11 at 09:04
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I don't think it is possible, because even when you make libA.so wrap libB.so (what you described as covers), libA.so still depends on the functions of libB.so, so both have to be linked to your executable. The only workaround that I know it's what @thiton proposed or make libA.so implement libB.so without depending on it, i.e., implement all functions of libB.so or only the ones you need.

jmpcm
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  • As you mentioned, I already made libA.so implement libB.so without depending on it. It can possible because libA.so and libB.so is made by me. :) But I don't know how to remove dependency of executable file on libB.so. – spbear Sep 27 '11 at 09:14
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edit executable and replace

libA.so.0

with

libB.so.0

this works because sizeo of "libA.so.0" is the same as sizeo of "libB.so.0".

If u add or remove extra symbol it will break executable for sure.

GreenScape
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  • They have different size of name unfortunately. But libB.so's name is longer than libA.so's name. Is it possible? I'm worry about other side effects. – spbear Sep 27 '11 at 09:30
  • no, unfortunately not :( but i can't see a problem making symbolic link. – GreenScape Sep 29 '11 at 08:39