From d4efd5ab810e92202efe672be29136324dd2a3f9 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?D=C4=81vis=20Mos=C4=81ns?= <davispuh@gmail.com>

Date: Mon, 28 Dec 2015 05:43:18 +0200

Subject: [PATCH] Check for NULL from glGetString

glGetString can return NULL pointer in case of error

so check for it before using.

Change-Id: Ia07424c8f2b3ce6dce675514900a509e3ef3b739

---

 src/particles/qquickimageparticle.cpp              |  6 ++++--

 src/quick/scenegraph/qsgcontext.cpp                | 22 ++++++++++++++++------

 .../qsgdefaultdistancefieldglyphcache.cpp          |  8 +++++---

 src/quick/scenegraph/util/qsgatlastexture.cpp      |  4 ++--

 4 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/particles/qquickimageparticle.cpp b/src/particles/qquickimageparticle.cpp

index d78a350..b54861e 100644

--- a/src/particles/qquickimageparticle.cpp

+++ b/src/particles/qquickimageparticle.cpp

@@ -1276,14 +1276,16 @@ void QQuickImageParticle::finishBuildParticleNodes(QSGNode** node)

     // OS X 10.8.3 introduced a bug in the AMD drivers, for at least the 2011 macbook pros,

     // causing point sprites who read gl_PointCoord in the frag shader to come out as

     // green-red blobs.

-    if (perfLevel < Deformable && strstr((char *) glGetString(GL_VENDOR), "ATI")) {

+    const char *vendor = (const char *) glGetString(GL_VENDOR);

+    if (perfLevel < Deformable && vendor && strstr(vendor, "ATI")) {

         perfLevel = Deformable;

     }

 #endif

 #ifdef Q_OS_LINUX

     // Nouveau drivers can potentially freeze a machine entirely when taking the point-sprite path.

-    if (perfLevel < Deformable && strstr((const char *) glGetString(GL_VENDOR), "nouveau"))

+    const char *vendor = (const char *) glGetString(GL_VENDOR);

+    if (perfLevel < Deformable && vendor && strstr(vendor, "nouveau"))

         perfLevel = Deformable;

 #endif

diff --git a/src/quick/scenegraph/qsgcontext.cpp b/src/quick/scenegraph/qsgcontext.cpp

index dd6977e..43d549f 100644

--- a/src/quick/scenegraph/qsgcontext.cpp

+++ b/src/quick/scenegraph/qsgcontext.cpp

@@ -624,14 +624,24 @@ void QSGRenderContext::initialize(QOpenGLContext *context)

     m_sg->renderContextInitialized(this);

 #ifdef Q_OS_LINUX

+    while (funcs->glGetError() != GL_NO_ERROR);

+

     const char *vendor = (const char *) funcs->glGetString(GL_VENDOR);

-    if (strstr(vendor, "nouveau"))

-        m_brokenIBOs = true;

     const char *renderer = (const char *) funcs->glGetString(GL_RENDERER);

-    if (strstr(renderer, "llvmpipe"))

-        m_serializedRender = true;

-    if (strstr(vendor, "Hisilicon Technologies") && strstr(renderer, "Immersion.16"))

-        m_brokenIBOs = true;

+

+    if (vendor && renderer) {

+        if (strstr(vendor, "nouveau"))

+            m_brokenIBOs = true;

+        if (strstr(renderer, "llvmpipe"))

+            m_serializedRender = true;

+        if (strstr(vendor, "Hisilicon Technologies") && strstr(renderer, "Immersion.16"))

+            m_brokenIBOs = true;

+    } else {

+        GLenum err;

+        while ((err = funcs->glGetError()) != GL_NO_ERROR) {

+            qWarning("QSGRenderContext::initialize: GL error %x from glGetString", err);

+        }

+    }

 #endif

     emit initialized();

diff --git a/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp b/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp

index dcc485c..43e234b 100644

--- a/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp

+++ b/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp

@@ -488,9 +488,11 @@ bool QSGDefaultDistanceFieldGlyphCache::useTextureUploadWorkaround() const

     static bool set = false;

     static bool useWorkaround = false;

     if (!set) {

-        useWorkaround = qstrcmp(reinterpret_cast<const char*>(m_funcs->glGetString(GL_RENDERER)),

-                                "Mali-400 MP") == 0;

-        set = true;

+        const char *renderer = reinterpret_cast<const char*>(m_funcs->glGetString(GL_RENDERER));

+        if (renderer) {

+            useWorkaround = qstrcmp(renderer, "Mali-400 MP") == 0;

+            set = true;

+        }

     }

     return useWorkaround;

 }

diff --git a/src/quick/scenegraph/util/qsgatlastexture.cpp b/src/quick/scenegraph/util/qsgatlastexture.cpp

index 8e8e870..d726907 100644

--- a/src/quick/scenegraph/util/qsgatlastexture.cpp

+++ b/src/quick/scenegraph/util/qsgatlastexture.cpp

@@ -150,13 +150,13 @@ Atlas::Atlas(const QSize &size)

         wrongfullyReportsBgra8888Support = false;

     const char *ext = (const char *) QOpenGLContext::currentContext()->functions()->glGetString(GL_EXTENSIONS);

-    if (!wrongfullyReportsBgra8888Support

+    if (!wrongfullyReportsBgra8888Support && ext

             && (strstr(ext, "GL_EXT_bgra")

                 || strstr(ext, "GL_EXT_texture_format_BGRA8888")

                 || strstr(ext, "GL_IMG_texture_format_BGRA8888"))) {

         m_internalFormat = m_externalFormat = GL_BGRA;

 #ifdef Q_OS_IOS

-    } else if (strstr(ext, "GL_APPLE_texture_format_BGRA8888")) {

+    } else if (ext && strstr(ext, "GL_APPLE_texture_format_BGRA8888")) {

         m_internalFormat = GL_RGBA;

         m_externalFormat = GL_BGRA;

 #endif // IOS

-- 

1.9.3