This package builds the time32 compat shims from musl 1.2.0+ as a standalone static (archive) library which can be linked (with --whole-archive) into LD_PRELOAD wrapper libraries. This allows such a library which needs to intercept one or more of the 63 functions replaced by a new time64 version to also intercept the old time32 symbol, for running legacy time32 binaries, automatically, without the need to be aware of time ABI differences. Just link it and everything magically works.

Create a symlink named musl to the root of the musl source tree (1.2.0+ or git master) elsewhere, or invoke make with the srcdir variable set to the location of the musl source tree, e.g.:

make srcdir=$HOME/src/musl

This assumes you're building on a musl-based system; if not, the CC variable also needs to be set to a musl-targeting cross compiler or the musl-gcc wrapper.

There is no install rule, as where or whether to install it is a matter of how you're using it.

Add -Wl,--whole-archive -lcompat_time32 -Wl,--no-whole-archive to the link command line. Special hacks (like prepending -Wl, to -lcompat_time32) may be needed if libtool is intercepting and mangling the command line.

musl's time32 compatibility symbols are not old time32 versions of the corresponding functions, but thin wrappers around the new time64 functions. By placing a copy of the wrapper into your LD_PRELOAD interceptor library, your interceptor library now defines the symbol in a way that it gets routed through its own wrapper function.

For example, a call from the application to the legacy time32 stat goes through:

1. stat symbol provided by libcompat_time32.a in your interceptor library

2. __stat_time64 symbol your interceptor library defines by implementing a function named stat after including <sys/stat.h>

3. __stat_time64 symbol in libc.so, obtained by calling dlsym(RTLD_NEXT, "stat") (assuming interceptor eventually calls the real function)

Without linking libcompat_time32.a in, the legacy application's call to the legacy time32 stat function would go to the definition in libc.so, unless the interceptor went through unreasonable hacks to define a symbol named stat and match the legacy structure ABI.