Public bug reported: system:Ubuntu 16.04.1 LTS Linux leno 4.4.0-34-generic #53-Ubuntu SMP Wed Jul 27 16:06:39 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux package in use: libc-bin 2.23-0ubuntu3
The ldd script comes with wired in paths for the 64 bit and 32 bit loaders, but other architectures are ignored. On a 64 bit Ubuntu installation, the 32 bit loader is not present by default, so 32 bit i386 dynamic executables are claimed to be "not a dynamic executable". This is simply wrong. On a 64 bit Intel sytem, ldd is frequently used to identify missing necessary 32 bit libraries for 32 bit executables, so their packages may be installed. It fails to do this unless ld-linux-x32.so.2 is present from the libc6-x32 package. A minimum fix would be to change the present message to: "not a dynamic executable or possibly a missing loader, like ld-linux-x32.so.2 from the libc6-x32 package." A better fix would be to use a program which can handle any architecture ELF file to report the needed libraries. Default Ubuntu installations do contain programs like file, readelf, and objdump which can successfully read these ELF files without loaders being present. The current ldd script even has a function, noelf, which might be better named "noloader" in which a fallback report may be issued to identify needed libraries. Using readelf in the "noloader" function, even different architectures may be correctly identified and their dependencies output. Below is a sample diff/patch for ldd which produces useful output for dynamic ELF files regardless of architecture: ====snip==== 97c97 < nonelf () --- > noloader () 99,100c99,105 < # Maybe extra code for non-ELF binaries. < return 1; --- > # Extra code for non-native architecture ELF binaries. > [ "$verbose" == "yes" ] && echo "No loader present for file $1, trying > other options." > readelf -h $1 1>/dev/null 2>&1 > if [ $? -eq 0 ]; then > readelf -h $1 | egrep "Class|Type|Machine" && readelf -d $1 | grep > NEEDED > fi > return $? 173,174c178,179 < # This can be a non-ELF binary or no binary at all. < nonelf "$file" || { --- > # This can be an ELF with no loader present, a non-ELF binary or no > binary at all. > noloader "$file" || { ====snip=== Comparison of original ldd with updated lddtest on three EFL files of different architecture and a text file. The host machine does have the i386 loader installed, but nothing for ARM. The files: $ file x y z txt x: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.3, for GNU/Linux 2.6.14, not stripped y: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.0.0, not stripped z: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=41cf4d8c7bbc4d37af0b7a55a7b0c48f8adfb2f5, not stripped txt: ASCII text The original ldd output: $ ldd x y z txt x: not a dynamic executable y: linux-gate.so.1 => (0xf777d000) libm.so.6 => /lib/i386-linux-gnu/libm.so.6 (0xf76fe000) libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf7548000) /lib/ld-linux.so.2 (0x56633000) z: linux-vdso.so.1 => (0x00007fffc9dac000) libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f4f63531000) /lib64/ld-linux-x86-64.so.2 (0x0000557d89ab7000) txt: not a dynamic executable The patched ldd output (with the 386 loader present): $ ./lddtest x y z txt x: Class: ELF32 Type: EXEC (Executable file) Machine: ARM 0x00000001 (NEEDED) Shared library: [libdl.so.2] 0x00000001 (NEEDED) Shared library: [libc.so.6] y: linux-gate.so.1 => (0xf774c000) libm.so.6 => /lib/i386-linux-gnu/libm.so.6 (0xf76cd000) libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf7517000) /lib/ld-linux.so.2 (0x56644000) z: linux-vdso.so.1 => (0x00007ffe4388a000) libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9550131000) /lib64/ld-linux-x86-64.so.2 (0x000056018c00d000) txt: not a dynamic executable ** Affects: glibc (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1616609 Title: ldd reports incorrectly "not a dynamic executable" when the executable's loader is not present To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1616609/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs