commit 53457dbae92cb6fb12fac06cf0e874ff3c49528d
author Jesse Hall <jessehall@google.com> Wed Dec 14 16:54:06 2016 -0800
committer Jesse Hall <jessehall@google.com> Mon Jan 16 21:11:07 2017 -0800
tree 82cd394ce952fa70fe347c99a1755ba6d8c7504b
parent 90b25ed559f3d04777dbbc195ad5c95287990bf7

Load updated drivers using derived loader namespace

Bug: 33531483
Test: Launch vulkan apps w/ and w/o updated driver package
Change-Id: Ia73e1e33b637d6ffd96ea0480ed6d85b9f68dce3

vulkan/libvulkan/driver.cpp

diff --git a/vulkan/libvulkan/driver.cpp b/vulkan/libvulkan/driver.cpp
index 800e474..df2526c 100644
--- a/vulkan/libvulkan/driver.cpp
+++ b/vulkan/libvulkan/driver.cpp
@@ -21,10 +21,15 @@
 
 #include <algorithm>
 #include <array>
+#include <dlfcn.h>
 #include <new>
 
 #include <log/log.h>
 
+#include <android/dlext.h>
+#include <cutils/properties.h>
+#include <gui/GraphicsEnv.h>
+
 #include "driver.h"
 #include "stubhal.h"
 
@@ -126,17 +131,74 @@
 
 Hal Hal::hal_;
 
+void* LoadLibrary(const android_dlextinfo& dlextinfo,
+                  const char* subname,
+                  int subname_len) {
+    const char kLibFormat[] = "vulkan.%*s.so";
+    char* name = static_cast<char*>(
+        alloca(sizeof(kLibFormat) + static_cast<size_t>(subname_len)));
+    sprintf(name, kLibFormat, subname_len, subname);
+    return android_dlopen_ext(name, RTLD_LOCAL | RTLD_NOW, &dlextinfo);
+}
+
+const std::array<const char*, 2> HAL_SUBNAME_KEY_PROPERTIES = {{
+    "ro.hardware." HWVULKAN_HARDWARE_MODULE_ID,
+    "ro.board.platform",
+}};
+
+int LoadUpdatedDriver(const hw_module_t** module) {
+    const android_dlextinfo dlextinfo = {
+        .flags = ANDROID_DLEXT_USE_NAMESPACE,
+        .library_namespace = android::GraphicsEnv::getInstance().getDriverNamespace(),
+    };
+    if (!dlextinfo.library_namespace)
+        return -ENOENT;
+
+    void* so = nullptr;
+    char prop[PROPERTY_VALUE_MAX];
+    for (auto key : HAL_SUBNAME_KEY_PROPERTIES) {
+        int prop_len = property_get(key, prop, nullptr);
+        if (prop_len > 0) {
+            so = LoadLibrary(dlextinfo, prop, prop_len);
+            if (so)
+                break;
+        }
+    }
+    if (!so)
+        return -ENOENT;
+
+    hw_module_t* hmi = static_cast<hw_module_t*>(dlsym(so, HAL_MODULE_INFO_SYM_AS_STR));
+    if (!hmi) {
+        ALOGE("couldn't find symbol '%s' in HAL library: %s", HAL_MODULE_INFO_SYM_AS_STR, dlerror());
+        dlclose(so);
+        return -EINVAL;
+    }
+    if (strcmp(hmi->id, HWVULKAN_HARDWARE_MODULE_ID) != 0) {
+        ALOGE("HAL id '%s' != '%s'", hmi->id, HWVULKAN_HARDWARE_MODULE_ID);
+        dlclose(so);
+        return -EINVAL;
+    }
+    hmi->dso = so;
+    *module = hmi;
+    ALOGD("loaded updated driver");
+    return 0;
+}
+
 bool Hal::Open() {
     ALOG_ASSERT(!hal_.dev_, "OpenHAL called more than once");
 
     // Use a stub device unless we successfully open a real HAL device.
     hal_.dev_ = &stubhal::kDevice;
 
-    const hwvulkan_module_t* module;
-    int result =
-        hw_get_module("vulkan", reinterpret_cast<const hw_module_t**>(&module));
+    int result;
+    const hwvulkan_module_t* module = nullptr;
+
+    result = LoadUpdatedDriver(reinterpret_cast<const hw_module_t**>(&module));
+    if (result == -ENOENT) {
+        result = hw_get_module(HWVULKAN_HARDWARE_MODULE_ID, reinterpret_cast<const hw_module_t**>(&module));
+    }
     if (result != 0) {
-        ALOGI("no Vulkan HAL present, using stub HAL");
+        ALOGV("unable to load Vulkan HAL, using stub HAL (result=%d)", result);
         return true;
     }