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QWaylandShmBuffer: use QTemporaryFile

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Instead of using mkstemp. Even current glibc versions do not open the
file with O_CLOEXEC, so this code is not thread-safe. QTemporaryFile is.
And since Qt 5.10, it will also use O_TMPFILE on Linux, so the file will
not actually exists on disk.

Take this opportunity to use the runtime directory instead of /tmp.
There's no guarantee that the /tmp filesystem can support mmap'ing,
while XDG_RUNTIME_DIR has that guarantee. It's also usually a tmpfs, so
no data will be leaked to disk.

Change-Id: I8d96dea9955d4c749b99fffd14cd5335d1114cef
Reviewed-by: Giulio Camuffo <giulio.camuffo@kdab.com>
This commit is contained in:
Thiago Macieira 2012-01-29 12:58:59 +01:00
parent 636ce8d733
commit 516c3b7fe9
1 changed files with 12 additions and 20 deletions
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32
src/plugins/platforms/wayland/qwaylandshmbackingstore.cpp
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@ -44,6 +44,8 @@
#include "qwaylandabstractdecoration_p.h" #include "qwaylandabstractdecoration_p.h"
#include <QtCore/qdebug.h> #include <QtCore/qdebug.h>
#include <QtCore/qstandardpaths.h>
#include <QtCore/qtemporaryfile.h>
#include <QtGui/QPainter> #include <QtGui/QPainter>
#include <QMutexLocker> #include <QMutexLocker>
#include <QLoggingCategory> #include <QLoggingCategory>
@ -52,10 +54,7 @@
#include <wayland-client-protocol.h> #include <wayland-client-protocol.h>
#include <unistd.h> #include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/mman.h> #include <sys/mman.h>
QT_BEGIN_NAMESPACE QT_BEGIN_NAMESPACE
namespace QtWaylandClient { namespace QtWaylandClient {
@ -72,28 +71,22 @@ QWaylandShmBuffer::QWaylandShmBuffer(QWaylandDisplay *display,
{ {
int stride = size.width() * 4; int stride = size.width() * 4;
int alloc = stride * size.height(); int alloc = stride * size.height();
char filename[] = "/tmp/wayland-shm-XXXXXX"; int fd;
int fd = mkstemp(filename);
if (fd < 0) {
qWarning("mkstemp %s failed: %s", filename, strerror(errno));
return;
}
int flags = fcntl(fd, F_GETFD);
if (flags != -1)
fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
if (ftruncate(fd, alloc) < 0) { QTemporaryFile tmp(QStandardPaths::writableLocation(QStandardPaths::RuntimeLocation) +
qWarning("ftruncate failed: %s", strerror(errno)); QLatin1String("/wayland-shm-XXXXXX"));
close(fd); if (!tmp.open() || !tmp.resize(alloc)) {
qWarning("QWaylandShmBuffer: failed: %s", qUtf8Printable(tmp.errorString()));
return; return;
} }
fd = tmp.handle();
// map ourselves: QFile::map() will unmap when the object is destroyed,
// but we want this mapping to persist (unmapping in destructor)
uchar *data = (uchar *) uchar *data = (uchar *)
mmap(NULL, alloc, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); mmap(NULL, alloc, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
unlink(filename);
if (data == (uchar *) MAP_FAILED) { if (data == (uchar *) MAP_FAILED) {
qWarning("mmap /dev/zero failed: %s", strerror(errno)); qErrnoWarning("QWaylandShmBuffer: mmap failed");
close(fd);
return; return;
} }
@ -105,7 +98,6 @@ QWaylandShmBuffer::QWaylandShmBuffer(QWaylandDisplay *display,
mShmPool = wl_shm_create_pool(shm->object(), fd, alloc); mShmPool = wl_shm_create_pool(shm->object(), fd, alloc);
init(wl_shm_pool_create_buffer(mShmPool,0, size.width(), size.height(), init(wl_shm_pool_create_buffer(mShmPool,0, size.width(), size.height(),
stride, wl_format)); stride, wl_format));
close(fd);
} }
QWaylandShmBuffer::~QWaylandShmBuffer(void) QWaylandShmBuffer::~QWaylandShmBuffer(void)