tree 0c722ced21166d5b6a79cc7c0aa14d073934bdd4
parent 22b5eb858dcbb537f2522ad920ca793348d574a2
author Erik Gilling <konkers@android.com> 1248838099 -0700
committer Erik Gilling <konkers@android.com> 1248838607 -0700

bionic/linker: keep track of opened libraries by basename

Prior to this change, the dynamic loader kept track of opened libraries
either by their base name (i.e., libfoo.so instead of /system/lib/libfoo.so)
when the shared library was loaded through the DT_NEEDED tag in an ELF header,
or by whatever name was passed to dlopen(). This created a number of problems,
among which:

1. dlopen("libfoo.so") and dlopen("/path/to/libfoo.so") would open the same
library twice;
2. dlopen("/path/to/libfoo.so") and then dlopen("libbar.so"), where libbar.so
depends on libfoo.so, would open libfoo.so twice.

This patch makes the dynamic loader keep track of each loaded library by
basename, which resolves the above ambiguity. The patch also enforces
library lookup by base name, which means that it will refuse to load another
library that has the same name.

Thanks for the inspiration Iliyan.

Signed-off-by: Erik Gilling <konkers@android.com>
Cc: Iliyan Malchev <malchev@google.com>