[libusb] Link with -znodelete to fix crash on unload of dl-opened code (rhbz#996760)

[Hans de Goede]

commit 2723ca9ecb9e71da3f60200eab18f7b71bf0180f
Author: Hans de Goede <hdegoede at redhat.com>
Date:   Wed Aug 14 19:33:03 2013 +0200

    Link with -znodelete to fix crash on unload of dl-opened code (rhbz#996760)

 ...Link-with-znodelete-to-disallow-unloading.patch |   51 ++++++++++++++++++++
 libusb.spec                                        |    7 ++-
 2 files changed, 57 insertions(+), 1 deletions(-)
---
diff --git a/0001-Link-with-znodelete-to-disallow-unloading.patch b/0001-Link-with-znodelete-to-disallow-unloading.patch
new file mode 100644
index 0000000..4534ab7
--- /dev/null
+++ b/0001-Link-with-znodelete-to-disallow-unloading.patch
@@ -0,0 +1,51 @@
+From a9e8373030b39aadfc33af67443085df83e9e344 Mon Sep 17 00:00:00 2001
+From: Daniel Berrange <berrange at 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 at 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
+
diff --git a/libusb.spec b/libusb.spec
index 9b87a68..3ed2f47 100644
--- a/libusb.spec
+++ b/libusb.spec
@@ -1,13 +1,14 @@
 Name: libusb
 Epoch: 1
 Version: 0.1.5
-Release: 1%{?dist}
+Release: 2%{?dist}
 Summary: A library which allows userspace access to USB devices
 Group: System Environment/Libraries
 License: LGPLv2+
 URL: http://sourceforge.net/projects/libusb/
 Source0: http://downloads.sourceforge.net/libusb/libusb-compat-%{version}.tar.bz2
 Patch0: libusb-config-multilib.patch
+Patch1: 0001-Link-with-znodelete-to-disallow-unloading.patch
 BuildRequires: libusb1-devel
 
 %description
@@ -31,6 +32,7 @@ libusb-1.0 library instead of this one.
 %prep
 %setup -q -n libusb-compat-%{version}
 %patch0 -p1 -b .config-multilib
+%patch1 -p1
 
 
 %build
@@ -59,6 +61,9 @@ rm $RPM_BUILD_ROOT%{_libdir}/libusb.la
 
 
 %changelog
+* Wed Aug 14 2013 Hans de Goede <hdegoede at redhat.com> - 0.1.5-2
+- Link with -znodelete to fix crash on unload of dl-opened code (rhbz#996760)
+
 * Sun Aug 04 2013 Hans de Goede <hdegoede at redhat.com> - 0.1.5-1
 - Update to 0.1.5 (#965414)
 - Drop unused -static subpackage