[Bug binutils/24984] New: Objcopy -I binary --rename-section reserves space for input file, but doesn't include file's contents in .o file

[antonone+sourceware at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=24984

            Bug ID: 24984
           Summary: Objcopy -I binary --rename-section reserves space for
                    input file, but doesn't include file's contents in .o
                    file
           Product: binutils
           Version: 2.32
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: binutils
          Assignee: unassigned at sourceware dot org
          Reporter: antonone+sourceware at gmail dot com
  Target Milestone: ---

Steps to reproduce:

    # 1. Create a 500MB file with random data in it
    $ dd if=/dev/urandom of=hugefile.bin bs=1M count=500

    # 2. Create an object file that will include this file above, use the
--rename-section option to put it into a new section:
    $ objcopy -I binary -B i386 -O elf64-x86-64 --rename-section
.data=.CustomData,readonly /bin/ls test.o

    # 3. Open test.o in a hexeditor: observe that 99% of the file is all
zeroes, instead of the content of hugefile.bin. At the same time, test.o has a
proper file size.

    $ 4. Verify the contents of the output file. Notice the huge gap between
0x30 and 0x1f400050, meaning all data in this range is all zeroes:
    $ cat dst.o | xxd | grep -v "0000 0000 0000 0000 0000 0000 0000 0000"
    00000000: 7f45 4c46 0201 0100 0000 0000 0000 0000  .ELF............
    00000010: 0100 3e00 0100 0000 0000 0000 0000 0000  ..>.............
    00000020: 0000 0000 0000 0000 3001 401f 0000 0000  ........0.@.....
    00000030: 0000 0000 4000 0000 0000 4000 0500 0400  ....@.....@.....
    1f400050: 0000 0000 0000 0000 0000 0000 0300 0100  ................
    1f400070: 0100 0000 1000 0100 0000 0000 0000 0000  ................
    ....

I've done the same steps on FreeBSD, which uses objcopy from elftoolchain, and
it works correctly. The objcopy tool from binutils works correctly when not
using the --rename-section option, but it also should work correctly with the
--rename-section option.

I've checked this on 2.32, as well as I've compiled by own objcopy
v2.32.51.20190909, and the bug is still there.

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