[PATCH] Don't use libudev for glx/dri3

[Keith Packard]

libudev doesn't have a stable API/ABI, and if the application wants to use one
version, we'd best not load another into libGL.

Signed-off-by: Keith Packard <keithp at keithp.com>
---

Sorry for the patch spam; I hadn't rebased in a while and there was a
configure.ac conflict. Here's a version which should apply cleanly to master.

 configure.ac          |   8 ----
 src/glx/dri3_common.c | 104 +++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 90 insertions(+), 22 deletions(-)

diff --git a/configure.ac b/configure.ac
index fb16338..656d9d0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -821,9 +821,6 @@ xyesno)
         PKG_CHECK_MODULES([DRI2PROTO], [dri2proto >= $DRI2PROTO_REQUIRED])
         GL_PC_REQ_PRIV="$GL_PC_REQ_PRIV libdrm >= $LIBDRM_REQUIRED"
         if test x"$enable_dri3" = xyes; then
-            if test x"$have_libudev" != xyes; then
-              AC_MSG_ERROR([DRI3 requires libudev >= $LIBUDEV_REQUIRED])
-            fi
             PKG_CHECK_MODULES([DRI3PROTO], [dri3proto >= $DRI3PROTO_REQUIRED])
             PKG_CHECK_MODULES([PRESENTPROTO], [presentproto >= $PRESENTPROTO_REQUIRED])
         fi
@@ -847,11 +844,6 @@ xyesno)
     X11_INCLUDES="$X11_INCLUDES $DRIGL_CFLAGS"
     GL_LIB_DEPS="$DRIGL_LIBS"
 
-    if test x"$enable_dri3$have_libudev" = xyesyes; then
-        X11_INCLUDES="$X11_INCLUDES $LIBUDEV_CFLAGS"
-        GL_LIB_DEPS="$GL_LIB_DEPS $LIBUDEV_LIBS"
-    fi
-
     # need DRM libs, $PTHREAD_LIBS, etc.
     GL_LIB_DEPS="$GL_LIB_DEPS $LIBDRM_LIBS -lm $PTHREAD_LIBS $DLOPEN_LIBS"
     GL_PC_LIB_PRIV="-lm $PTHREAD_LIBS $DLOPEN_LIBS"
diff --git a/src/glx/dri3_common.c b/src/glx/dri3_common.c
index c758f96..7330d79 100644
--- a/src/glx/dri3_common.c
+++ b/src/glx/dri3_common.c
@@ -72,22 +72,41 @@
 #include "dri3_priv.h"
 
 #define DRIVER_MAP_DRI3_ONLY
+
 #include "pci_ids/pci_id_driver_map.h"
 
+static dev_t
+dri3_rdev_from_fd(int fd)
+{
+   struct stat buf;
+
+   if (fstat(fd, &buf) < 0) {
+      ErrorMessageF("DRI3: failed to stat fd %d", fd);
+      return 0;
+   }
+   return buf.st_rdev;
+}
+
+/*
+ * There are multiple udev library versions, and they aren't polite about
+ * symbols, so just avoid using it until some glorious future when the udev
+ * developers figure out how to not break things
+ */
+
+#define USE_UDEV 0
+#if USE_UDEV
 #include <libudev.h>
 
 static struct udev_device *
 dri3_udev_device_new_from_fd(struct udev *udev, int fd)
 {
    struct udev_device *device;
-   struct stat buf;
+   dev_t rdev = dri3_rdev_from_fd(fd);
 
-   if (fstat(fd, &buf) < 0) {
-      ErrorMessageF("DRI3: failed to stat fd %d", fd);
+   if (rdev == 0)
       return NULL;
-   }
 
-   device = udev_device_new_from_devnum(udev, 'c', buf.st_rdev);
+   device = udev_device_new_from_devnum(udev, 'c', rdev);
    if (device == NULL) {
       ErrorMessageF("DRI3: could not create udev device for fd %d", fd);
       return NULL;
@@ -96,19 +115,20 @@ dri3_udev_device_new_from_fd(struct udev *udev, int fd)
    return device;
 }
 
-char *
-dri3_get_driver_for_fd(int fd)
+static int
+dri3_get_pci_id_from_fd(int fd, int *vendorp, int *chipp)
 {
    struct udev *udev;
    struct udev_device *device, *parent;
    const char *pci_id;
-   char *driver = NULL;
-   int vendor_id, chip_id, i, j;
+   int ret = 0;
 
    udev = udev_new();
+   if (!udev)
+      goto no_udev;
    device = dri3_udev_device_new_from_fd(udev, fd);
    if (device == NULL)
-      return NULL;
+      goto no_dev;
 
    parent = udev_device_get_parent(device);
    if (parent == NULL) {
@@ -118,10 +138,69 @@ dri3_get_driver_for_fd(int fd)
 
    pci_id = udev_device_get_property_value(parent, "PCI_ID");
    if (pci_id == NULL ||
-       sscanf(pci_id, "%x:%x", &vendor_id, &chip_id) != 2) {
+       sscanf(pci_id, "%x:%x", vendorp, chipp) != 2) {
       ErrorMessageF("DRI3: malformed or no PCI ID");
       goto out;
    }
+   ret = 1;
+
+out:
+   udev_device_unref(device);
+no_dev:
+   udev_unref(udev);
+no_udev:
+   return ret;
+}
+#else
+
+#define SYS_PATH_MAX    256
+
+static int
+dri3_read_hex(dev_t rdev, char *entry, int *value)
+{
+   char         path[SYS_PATH_MAX];
+   FILE         *f;
+   int          r;
+
+   snprintf(path, sizeof (path), "/sys/dev/char/%u:%u/device/%s",
+            major(rdev), minor(rdev), entry);
+
+   f = fopen(path,"r");
+   if (f == NULL)
+      return 0;
+
+   r = fscanf(f, "0x%x\n", value);
+   fclose(f);
+   if (r != 1)
+      return 0;
+   return 1;
+}
+
+static int
+dri3_get_pci_id_from_fd(int fd, int *vendorp, int *chipp)
+{
+   dev_t        rdev = dri3_rdev_from_fd(fd);
+   
+   if (!rdev)
+      return 0;
+
+   if (!dri3_read_hex(rdev, "vendor", vendorp))
+      return 0;
+   if (!dri3_read_hex(rdev, "device", chipp))
+      return 0;
+   return 1;
+}
+
+#endif
+
+char *
+dri3_get_driver_for_fd(int fd)
+{
+   char *driver = NULL;
+   int vendor_id, chip_id, i, j;
+
+   if (!dri3_get_pci_id_from_fd(fd, &vendor_id, &chip_id))
+      return NULL;
 
    for (i = 0; driver_map[i].driver; i++) {
       if (vendor_id != driver_map[i].vendor_id)
@@ -139,8 +218,5 @@ dri3_get_driver_for_fd(int fd)
    }
 
 out:
-   udev_device_unref(device);
-   udev_unref(udev);
-
    return driver;
 }
-- 
1.8.4.2