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From a9e8373030b39aadfc33af67443085df83e9e344 Mon Sep 17 00:00:00 2001
From: Daniel Berrange <berrange@redhat.com>
Date: Wed, 14 Aug 2013 16:00:56 +0200
Subject: [libusb-compat PATCH] Link with -znodelete to disallow unloading

Since libusb-0.1 did not have any init / exit function, code using the
libusb-0.1 API will not call libusb_exit.

Now, libgphoto uses libusb and will dlopen() and dlclose() it. Unfortunately
since there is no way to ensure libusb_close() is called, when libgphoto
dlcloses the libusb.so library, the thread from libusbx.so will not be
stopped. So a thread will remain running, executing code from a memory
region that has now been freed. Crash-tastic results ensue.

I don't see a good way to fix this from libusb or libusbx, given the need to
preserve the existing API of libusb.

If, however, we link libusb.so using  -znodelete, we will prevent it from
ever being unloaded, despite the dlclose() calls. This is not ideal, but
better than allowing it to be unloaded which is a guaranteed crash.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 libusb/Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libusb/Makefile.am b/libusb/Makefile.am
index 33a609a..a20fdb5 100644
--- a/libusb/Makefile.am
+++ b/libusb/Makefile.am
@@ -5,5 +5,5 @@ libusb_la_SOURCES = core.c usbi.h
 libusb_la_CFLAGS = -fvisibility=hidden $(AM_CFLAGS) $(LIBUSB_1_0_CFLAGS)
 libusb_la_LIBADD = $(LIBUSB_1_0_LIBS)
 libusb_la_LDFLAGS = -version-info $(LT_MAJOR):$(LT_REVISION):$(LT_AGE) \
-	-release 0.1
+	-release 0.1 -Wl,-z -Wl,nodelete
 
--- libusb-compat-0.1.5.orig/libusb/Makefile.in	2013-05-21 00:40:35.000000000 +0100
+++ libusb-compat-0.1.5.orig/libusb/Makefile.in	2013-08-13 22:20:32.831532426 +0100
@@ -297,7 +297,7 @@ libusb_la_SOURCES = core.c usbi.h
 libusb_la_CFLAGS = -fvisibility=hidden $(AM_CFLAGS) $(LIBUSB_1_0_CFLAGS)
 libusb_la_LIBADD = $(LIBUSB_1_0_LIBS)
 libusb_la_LDFLAGS = -version-info $(LT_MAJOR):$(LT_REVISION):$(LT_AGE) \
-	-release 0.1
+	-release 0.1 -Wl,-z -Wl,nodelete
 
 all: all-am
 
-- 
1.8.3.1