diff options
| -rw-r--r-- | shm.c | 33 |
1 files changed, 31 insertions, 2 deletions
@@ -1,7 +1,9 @@ #include "shm.h" -#include <unistd.h> #include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> #include <sys/types.h> #include <sys/mman.h> @@ -13,6 +15,10 @@ #include "log.h" #include "stride.h" +#if !defined(MAP_UNINITIALIZED) + #define MAP_UNINITIALIZED 0 +#endif + static void buffer_destroy(struct buffer *buf) { @@ -53,7 +59,21 @@ shm_get_buffer(struct wl_shm *shm, int width, int height, unsigned long cookie) pixman_image_t *pix = NULL; /* Backing memory for SHM */ - pool_fd = memfd_create("wbg-wayland-shm-buffer-pool", MFD_CLOEXEC); + + /* + * Older kernels reject MFD_NOEXEC_SEAL with EINVAL. Try first + * *with* it, and if that fails, try again *without* it. + */ + errno = 0; + pool_fd = memfd_create( + "wbg-wayland-shm-buffer-pool", + MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC_SEAL); + + if (pool_fd < 0 && errno == EINVAL) { + pool_fd = memfd_create( + "wbg-wayland-shm-buffer-pool", MFD_CLOEXEC | MFD_ALLOW_SEALING); + } + if (pool_fd == -1) { LOG_ERRNO("failed to create SHM backing memory file"); goto err; @@ -73,6 +93,15 @@ shm_get_buffer(struct wl_shm *shm, int width, int height, unsigned long cookie) goto err; } + /* Seal file - we no longer allow any kind of resizing */ + /* TODO: wayland mmaps(PROT_WRITE), for some unknown reason, hence we cannot use F_SEAL_FUTURE_WRITE */ + if (fcntl(pool_fd, F_ADD_SEALS, + F_SEAL_GROW | F_SEAL_SHRINK | /*F_SEAL_FUTURE_WRITE |*/ F_SEAL_SEAL) < 0) + { + LOG_ERRNO("failed to seal SHM backing memory file"); + /* This is not a fatal error */ + } + pool = wl_shm_create_pool(shm, pool_fd, size); if (pool == NULL) { LOG_ERR("failed to create SHM pool"); |