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authorVlad Zahorodnii <vlad.zahorodnii@kde.org>2022-11-17 15:25:37 +0200
committerVlad Zahorodnii <vlad.zahorodnii@kde.org>2022-11-18 11:13:25 +0200
commit0c1cbb376e0cf878e3a91ab4917fe784a3b4c547 (patch)
treed4b4b365479354a3b52309ce9611c9f6bd68a197 /src/client/qwaylandshmbackingstore.cpp
parent349bce0feaa7aa64081a6e2ef3c8611236d26975 (diff)
Client: Add F_SEAL_SHRINK seal to shm backing file
This lets libwayland-server avoid installing a SIGBUS handler when it wants to mmap() the backing file and access the contents of shared memory client buffers. Change-Id: Id0b17f729799535d73e8700c5a99c32fd88a068a Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org> Reviewed-by: David Edmundson <davidedmundson@kde.org>
Diffstat (limited to 'src/client/qwaylandshmbackingstore.cpp')
-rw-r--r--src/client/qwaylandshmbackingstore.cpp8
1 files changed, 7 insertions, 1 deletions
diff --git a/src/client/qwaylandshmbackingstore.cpp b/src/client/qwaylandshmbackingstore.cpp
index a8e59637a..2e0c2491f 100644
--- a/src/client/qwaylandshmbackingstore.cpp
+++ b/src/client/qwaylandshmbackingstore.cpp
@@ -16,6 +16,7 @@
#include <QtWaylandClient/private/wayland-wayland-client-protocol.h>
+#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
@@ -25,6 +26,9 @@
# ifndef MFD_CLOEXEC
# define MFD_CLOEXEC 0x0001U
# endif
+# ifndef MFD_ALLOW_SEALING
+# define MFD_ALLOW_SEALING 0x0002U
+# endif
#endif
QT_BEGIN_NAMESPACE
@@ -39,7 +43,9 @@ QWaylandShmBuffer::QWaylandShmBuffer(QWaylandDisplay *display,
int fd = -1;
#ifdef SYS_memfd_create
- fd = syscall(SYS_memfd_create, "wayland-shm", MFD_CLOEXEC);
+ fd = syscall(SYS_memfd_create, "wayland-shm", MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ if (fd >= 0)
+ fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_SEAL);
#endif
QScopedPointer<QFile> filePointer;