From 4556c734700da2dd95d4f148d6929a537882bade Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Thu, 23 Jan 2014 13:12:26 -0800
Subject: [PATCH] loader: Use dlsym to get our udev symbols instead of explicit
 linking.
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Steam links against libudev.so.0, while we're linking against
libudev.so.1.  The result is that the symbol names (which are the same in
the two libraries) end up conflicting, and some of the usage of .so.1
calls the .so.0 bits, which have different internal structures, and
segfaults happen.

By using a dlopen() with RTLD_LOCAL, we can explicitly look for the
symbols we want, while they get the symbols they want.

Reviewed-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
Tested-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Tested-by: Mike Lothian <mike@fireburn.co.uk>
---
 configure.ac             |  2 +-
 src/egl/main/Makefile.am |  2 +-
 src/loader/Makefile.am   |  5 +----
 src/loader/loader.c      | 42 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/configure.ac b/configure.ac
index 33ac9225948..d266d96b674 100644
--- a/configure.ac
+++ b/configure.ac
@@ -858,7 +858,7 @@ xyesno)
 
     if test x"$enable_dri3$have_libudev" = xyesyes; then
         X11_INCLUDES="$X11_INCLUDES $LIBUDEV_CFLAGS"
-        GL_LIB_DEPS="$GL_LIB_DEPS $LIBUDEV_LIBS"
+        GL_LIB_DEPS="$GL_LIB_DEPS"
     fi
 
     # need DRM libs, $PTHREAD_LIBS, etc.
diff --git a/src/egl/main/Makefile.am b/src/egl/main/Makefile.am
index 60cb6006b50..e12aeae59b9 100644
--- a/src/egl/main/Makefile.am
+++ b/src/egl/main/Makefile.am
@@ -112,7 +112,7 @@ if HAVE_EGL_DRIVER_DRI2
 AM_CFLAGS += -D_EGL_BUILT_IN_DRIVER_DRI2
 AM_CFLAGS += -DHAVE_XCB_DRI2
 libEGL_la_LIBADD += ../drivers/dri2/libegl_dri2.la
-libEGL_la_LIBADD += $(LIBUDEV_LIBS) $(DLOPEN_LIBS) $(LIBDRM_LIBS)
+libEGL_la_LIBADD += $(DLOPEN_LIBS) $(LIBDRM_LIBS)
 endif
 
 # Provide compatibility with scripts for the old Mesa build system for
diff --git a/src/loader/Makefile.am b/src/loader/Makefile.am
index 371dd575c09..bddf7ac35ed 100644
--- a/src/loader/Makefile.am
+++ b/src/loader/Makefile.am
@@ -29,9 +29,6 @@ libloader_la_CPPFLAGS = \
 	$(VISIBILITY_CFLAGS) \
 	$(LIBUDEV_CFLAGS)
 
-libloader_la_LIBADD = \
-	$(LIBUDEV_LIBS)
-
 if !HAVE_LIBDRM
 libloader_la_CPPFLAGS += \
 	-D__NOT_HAVE_DRM_H
@@ -39,7 +36,7 @@ else
 libloader_la_CPPFLAGS += \
 	$(LIBDRM_CFLAGS)
 
-libloader_la_LIBADD += \
+libloader_la_LIBADD = \
 	$(LIBDRM_LIBS)
 endif
 
diff --git a/src/loader/loader.c b/src/loader/loader.c
index a5bd7692e6e..63b977aa743 100644
--- a/src/loader/loader.c
+++ b/src/loader/loader.c
@@ -67,6 +67,8 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
+#include <assert.h>
+#include <dlfcn.h>
 #include "loader.h"
 
 #ifndef __NOT_HAVE_DRM_H
@@ -92,11 +94,37 @@ static void (*log_)(int level, const char *fmt, ...) = default_logger;
 #ifdef HAVE_LIBUDEV
 #include <libudev.h>
 
+static void *udev_handle = NULL;
+
+static void *
+udev_dlopen_handle(void)
+{
+   if (!udev_handle) {
+      udev_handle = dlopen("libudev.so.1", RTLD_LOCAL | RTLD_LAZY);
+   }
+
+   return udev_handle;
+}
+
+static void *
+asserted_dlsym(void *dlopen_handle, const char *name)
+{
+   void *result = dlsym(dlopen_handle, name);
+   assert(result);
+   return result;
+}
+
+#define UDEV_SYMBOL(ret, name, args) \
+   ret (*name) args = asserted_dlsym(udev_dlopen_handle(), #name);
+
+
 static inline struct udev_device *
 udev_device_new_from_fd(struct udev *udev, int fd)
 {
    struct udev_device *device;
    struct stat buf;
+   UDEV_SYMBOL(struct udev_device *, udev_device_new_from_devnum,
+               (struct udev *udev, char type, dev_t devnum));
 
    if (fstat(fd, &buf) < 0) {
       log_(_LOADER_WARNING, "MESA-LOADER: failed to stat fd %d", fd);
@@ -119,6 +147,14 @@ loader_get_pci_id_for_fd(int fd, int *vendor_id, int *chip_id)
    struct udev *udev = NULL;
    struct udev_device *device = NULL, *parent;
    const char *pci_id;
+   UDEV_SYMBOL(struct udev *, udev_new, (void));
+   UDEV_SYMBOL(struct udev_device *, udev_device_get_parent,
+               (struct udev_device *));
+   UDEV_SYMBOL(const char *, udev_device_get_property_value,
+               (struct udev_device *, const char *));
+   UDEV_SYMBOL(struct udev_device *, udev_device_unref,
+               (struct udev_device *));
+   UDEV_SYMBOL(struct udev *, udev_unref, (struct udev *));
 
    *chip_id = -1;
 
@@ -240,6 +276,12 @@ loader_get_device_name_for_fd(int fd)
    struct udev *udev;
    struct udev_device *device;
    const char *const_device_name;
+   UDEV_SYMBOL(struct udev *, udev_new, (void));
+   UDEV_SYMBOL(const char *, udev_device_get_devnode,
+               (struct udev_device *));
+   UDEV_SYMBOL(struct udev_device *, udev_device_unref,
+               (struct udev_device *));
+   UDEV_SYMBOL(struct udev *, udev_unref, (struct udev *));
 
    udev = udev_new();
    device = udev_device_new_from_fd(udev, fd);