How can you determine installed versions of the glibc libraries? - linux

Question

I'm working with an embedded Linux deployment and am using a cross compiler tool chain that doesn't compile I2C library function calls.
How do I determine the precise versions of the libraries on the system so that I may rebuild the tool chain?
I don't intend to replace the libraries deployed, as I do know they work (including I2C), so I believe I need the following:
Binutils version
GCC version
GLIBC
Kernel (for the headers)
I think I can assume from the following that the binutils library is version 2.2.5. The kernel is modded for which I've the source.
root#dev-box />ls /lib/ -al
drwxrwxrwx 3 root root 1024 Apr 27 09:44 .
drwxrwxrwx 14 root root 1024 Jan 1 1970 ..
-rwxrwxrwx 1 root root 105379 Jan 1 1970 ld-2.2.5.so
lrwxrwxrwx 1 root root 16 Jan 1 1970 ld-linux.so.2 -> /lib/ld-2.2.5.so
lrwxrwxrwx 1 root root 16 Jan 1 1970 ld.so.1 -> /lib/ld-2.2.5.so
-rwxrwxrwx 1 root root 1288601 Jan 1 1970 libc.so.6
-rwxrwxrwx 1 root root 25441 Jan 1 1970 libcrypt.so.1
-rwxrwxrwx 1 root root 14303 Jan 1 1970 libdl.so.2
-rwxrwxrwx 1 root root 36800 Jan 1 1970 libgcc_s.so.1
-rwxrwxrwx 1 root root 530401 Jan 1 1970 libm.so.6
-rwxrwxrwx 1 root root 86626 Jan 1 1970 libnsl.so.1
-rwxrwxrwx 1 root root 17533 Jan 1 1970 libnss_dns.so.2
-rwxrwxrwx 1 root root 46324 Jan 1 1970 libnss_files.so.2
-rwxrwxrwx 1 root root 98633 Jan 1 1970 libpthread.so.0
-rwxrwxrwx 1 root root 69966 Jan 1 1970 libresolv.so.2
-rwxrwxrwx 1 root root 12897 Jan 1 1970 libutil.so.1

Answer 1

For glibc:
/lib/libc.so.6
Sounds maybe strange to run a so file but should print out version information in this case
For the kernel version use uname
For the binutils parsing the output of ld --versionmight yield what you expect, the same for gcc --version. This is a bit tedious but I do not know another way.

Answer 2

a more comprehensive answer can be found by running
find /lib -iname 'libc*.so'
On a recent system this will give you results like this that show i'm using glibc 2.28 here on ubuntu 18.10
/lib/x86_64-linux-gnu/libc-2.28.so
/lib/x86_64-linux-gnu/libcrypt-2.28.so
/lib/i386-linux-gnu/libc-2.28.so
/lib/i386-linux-gnu/libcrypt-2.28.so
For multiarch system you can have multiple copies for 386 and 64 modes , i think these should be the same .
i didn't have a /lib/libc.so.* on my system.

Answer 3

To know the current installed version of glibc, please compile and run the following C code.
#include <stdio.h>
#include <gnu/libc-version.h>
int main (void) { puts (gnu_get_libc_version ()); return 0; }
Cheers !!!