Avoid false positives on egl extension matching
Due to the strstr prefix match EGL_EXT_foo would be incorrectly matched
if EGL_EXT_foobar would be available but not foo.
This doesn't matter for the currently checked extensions but will matter
for EGL_EXT_image_dma_buf_import_modifiers vs
EGL_EXT_image_dma_buf_import
Code borrowed from weston
@@ -83,6 +83,24 @@ static bool egl_get_config(EGLDisplay disp, EGLint *attribs, EGLConfig *out,
return false;
}
+static bool check_egl_ext(const char *egl_exts, const char *ext) {
+ size_t extlen = strlen(ext);
+ const char *end = egl_exts + strlen(egl_exts);
+
+ while (egl_exts < end) {
+ if (*egl_exts == ' ') {
+ egl_exts++;
+ continue;
+ }
+ size_t n = strcspn(egl_exts, " ");
+ if (n == extlen && strncmp(ext, egl_exts, n) == 0) {
+ return true;
+ }
+ egl_exts += n;
+ }
+ return false;
+}
+
bool wlr_egl_init(struct wlr_egl *egl, EGLenum platform, void *remote_display,
EGLint *config_attribs, EGLint visual_id) {
if (!load_glapi()) {
@@ -137,17 +155,17 @@ bool wlr_egl_init(struct wlr_egl *egl, EGLenum platform, void *remote_display,
wlr_log(L_INFO, "GL vendor: %s", glGetString(GL_VENDOR));
wlr_log(L_INFO, "Supported OpenGL ES extensions: %s", egl->gl_exts_str);
- if (strstr(egl->egl_exts_str, "EGL_WL_bind_wayland_display") == NULL ||
- strstr(egl->egl_exts_str, "EGL_KHR_image_base") == NULL) {
+ if (!check_egl_ext(egl->egl_exts_str, "EGL_WL_bind_wayland_display") ||
+ !check_egl_ext(egl->egl_exts_str, "EGL_KHR_image_base")) {
wlr_log(L_ERROR, "Required egl extensions not supported");
goto error;
}
egl->egl_exts.buffer_age =
- strstr(egl->egl_exts_str, "EGL_EXT_buffer_age") != NULL;
+ check_egl_ext(egl->egl_exts_str, "EGL_EXT_buffer_age");
egl->egl_exts.swap_buffers_with_damage =
- strstr(egl->egl_exts_str, "EGL_EXT_swap_buffers_with_damage") != NULL ||
- strstr(egl->egl_exts_str, "EGL_KHR_swap_buffers_with_damage") != NULL;
+ check_egl_ext(egl->egl_exts_str, "EGL_EXT_swap_buffers_with_damage") ||
+ check_egl_ext(egl->egl_exts_str, "EGL_KHR_swap_buffers_with_damage");
return true;
