gcc: Reduce libc required version

c linux gcc linker libc
MonoThreaded picture MonoThreaded · Aug 22, 2012 · Viewed 23.9k times · Source

I am trying to run a newly compiled binary on some oldish 32bits RedHat distribution.
The binary is compiled C (not++) on a CentOS 32bits VM running libc v2.12.

RedHat complains about libc version: 

error while loading shared libraries: requires glibc 2.5 or later dynamic linker
Since my program is rather simplistic, It is most likely not using anything new from libc.

Is there a way to reduce libc version requirement

Answer

Michael Burr picture Michael Burr · Aug 22, 2012

An untested possible solution

What is "error while loading shared libraries: requires glibc 2.5 or later dynamic linker"?

The cause of this error is the dynamic binary (or one of its dependent shared libraries) you want to run only has .gnu.hash section, but the ld.so on the target machine is too old to recognize .gnu.hash; it only recognizes the old-school .hash section.

This usually happens when the dynamic binary in question is built using newer version of GCC. The solution is to recompile the code with either -static compiler command-line option (to create a static binary), or the following option:

-Wl,--hash-style=both

This tells the link editor ld to create both .gnu.hash and .hash sections.

According to ld documentation here, the old-school .hash section is the default, but the compiler can override it. For example, the GCC (which is version 4.1.2) on RHEL (Red Hat Enterprise Linux) Server release 5.5 has this line:

$ gcc -dumpspecs
....
*link:
%{!static:--eh-frame-hdr} %{!m32:-m elf_x86_64} %{m32:-m elf_i386} --hash-style=gnu   %{shared:-shared}   ....
                                                                   ^^^^^^^^^^^^^^^^
...

For more information, see here.

Related questions

Linking against older symbol version in a .so file

Using gcc and ld on x86_64 linux I need to link against a newer version of a library (glibc 2.14) but the executable needs to run on a system with an older version (2.5). Since the only incompatible symbol is memcpy (needing …

Read More
`bash: ./a.out: No such file or directory` on running executable produced by `ld`

Here is a Hello World code in C: // a.c #include <stdio.h> int main() { printf("Hello world\n"); return 0; } I compile it as gcc a.c, which produces a.out as expected and ./a.out prints Hello …

Read More
gcc debug symbols (-g flag) vs linker's -rdynamic option

glibc provides backtrace() and backtrace_symbols() to get the stack trace of a running program. But for this to work the program has to be built with linker's -rdynamic flag. What is the difference between -g flag passed to gcc …

Read More