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I am hacking an ARM-based device that is coming with a lightweight busybox:

[/mnt/sdcard/busybox]## busybox
BusyBox v1.24.1 (2017-09-29 00:55:28 PDT) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
Licensed under GPLv2. See source distribution for detailed
copyright notices.

Usage: busybox [function [arguments]...]
   or: busybox --list
   or: function [arguments]...

        BusyBox is a multi-call binary that combines many common Unix
        utilities into a single executable.  Most people will create a
        link to busybox for each function they wish to use and BusyBox
        will act like whatever it was invoked as.

Currently defined functions:
        ash, awk, cat, chmod, clear, cp, date, dd, devmem, df, dhcprelay, dmesg, dnsdomainname, dumpleases, echo, egrep, env, fgrep, find, flock,
        free, ftpd, getty, grep, halt, head, hostname, ifconfig, inetd, init, insmod, ipcs, kill, killall, killall5, linuxrc, ln, logger, login,
        logread, ls, lsmod, lsusb, md5sum, mkdir, mkdosfs, mkfs.vfat, modinfo, more, mount, mv, netstat, passwd, ping, pkill, poweroff, printf, ps,
        pwd, reboot, renice, reset, rm, rmmod, route, sed, sh, sleep, sort, strings, sync, sysctl, syslogd, tail, telnet, telnetd, tftp, time, top,
        touch, traceroute, tty, udhcpc, udhcpd, umount, uname, unlink, uptime, usleep, vi, volname, watch, wc

It is missing a few functions that I'd like (tar, gzip...). So I have started building busybox (1.36.0), that I aim to squeeze into the firmware image. I can make a working version of busybox if I statically link its libs. But the binary is too large and I'm trying to build it with dynamic links. Everything I try ends up that way:

[~]## ./busybox
/system/bin/sh: ./busybox: not found

Which seems to indicate to me that it is not able to find or work with the required libs.

[/mnt/sdcard/busybox]## echo $LD_LIBRARY_PATH
/lib:/system/lib:/vendor/lib:/mvs/lib:/usr/lib
[/mnt/sdcard/busybox]## ls -al /lib/lib*.so.6
lrwxrwxrwx root     root              2019-05-22 04:21 libc.so.6 -> libc-2.19-2014.04.so
lrwxrwxrwx root     root              2019-05-22 04:21 libm.so.6 -> libm-2.19-2014.04.so
lrwxrwxrwx root     root              2019-05-22 04:21 libstdc++.so.6 -> libstdc++.so.6.0.19

These seem to be the only dependencies, and they are present on the device:

[/mnt/sdcard/busybox]## echo $LD_LIBRARY_PATH
/lib:/system/lib:/vendor/lib:/mvs/lib:/usr/lib
[/mnt/sdcard/busybox]## ls /lib/lib*.so.6
/lib/libc.so.6
/lib/libm.so.6
/lib/libstdc++.so.6

Could it be a version mismatch at the kernel or library level? If yes, how do I align them?

I have tried copying the libs from my computer into the device, adding '.' to the LD_LIBRARY_PATH env variable, in vain. I note that the libs on my computer are much larger in disk size than the ones on the device.

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  • 1
    Have you tried building statically with uClibc?
    – fpmurphy
    Jun 5 at 12:28
  • @fpmurphy I have started studying this option but haven't made the time yet to get my hands dirty. uClibc or uClibc-ng are definiltely something I am going to try.
    – dotvav
    Jun 10 at 6:41

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