Add a tool to track down fd leaks.
Add a hook that's called upon file descriptor creation to libc, and a
library that uses it to capture backtraces for file descriptor creation,
to make it easier to hunt down file descriptor leaks.
Currently, this doesn't capture all of the ways of creating a file
descriptor, but completeness isn't required for this to be useful as
long as leaked file descriptors are created with a function that is
tracked. The primary unhandled case is binder, which receives file
descriptors as a payload in a not-trivially-parsable byte blob, but
there's a chance that the leak we're currently trying to track down
isn't of a file descriptor received over binder, so leave that for
later.
Bug: http://b/140703823
Test: manual
Change-Id: I308a14c2e234cdba4207157b634ab6b8bc539dd9
(cherry picked from commit b7eccd4b1577c101132e52d4a5313d5322dcae2d)
diff --git a/libc/private/bionic_globals.h b/libc/private/bionic_globals.h
index 8997ceb..4cc9bbe 100644
--- a/libc/private/bionic_globals.h
+++ b/libc/private/bionic_globals.h
@@ -100,6 +100,7 @@
__LIBC_HIDDEN__ libc_shared_globals* __libc_shared_globals();
__LIBC_HIDDEN__ void __libc_init_fdsan();
+__LIBC_HIDDEN__ void __libc_init_fdtrack();
__LIBC_HIDDEN__ void __libc_init_profiling_handlers();
__LIBC_HIDDEN__ void __libc_init_malloc(libc_globals* globals);