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
diff --git a/libc/bionic/legacy_32_bit_support.cpp b/libc/bionic/legacy_32_bit_support.cpp
index 2de1bc7..f08e582 100644
--- a/libc/bionic/legacy_32_bit_support.cpp
+++ b/libc/bionic/legacy_32_bit_support.cpp
@@ -37,27 +37,17 @@
#include <sys/vfs.h>
#include <unistd.h>
+#include "private/bionic_fdtrack.h"
+
#if defined(__LP64__)
#error This code is only needed on 32-bit systems!
#endif
// System calls we need.
-extern "C" int __fcntl64(int, int, void*);
extern "C" int __llseek(int, unsigned long, unsigned long, off64_t*, int);
extern "C" int __preadv64(int, const struct iovec*, int, long, long);
extern "C" int __pwritev64(int, const struct iovec*, int, long, long);
-// For fcntl we use the fcntl64 system call to signal that we're using struct flock64.
-int fcntl(int fd, int cmd, ...) {
- va_list ap;
-
- va_start(ap, cmd);
- void* arg = va_arg(ap, void*);
- va_end(ap);
-
- return __fcntl64(fd, cmd, arg);
-}
-
// For lseek64 we need to use the llseek system call which splits the off64_t in two and
// returns the off64_t result via a pointer because 32-bit kernels can't return 64-bit results.
off64_t lseek64(int fd, off64_t off, int whence) {