fi
AC_SUBST(GCC_CFLAGS)
-AC_CHECK_FUNCS([accept4 mkostemp])
+AC_CHECK_FUNCS([accept4 mkostemp posix_fallocate])
AC_CHECK_DECL(SFD_CLOEXEC,[],
[AC_MSG_ERROR("SFD_CLOEXEC is needed to compile wayland")],
* The file is suitable for buffer sharing between processes by
* transmitting the file descriptor over Unix sockets using the
* SCM_RIGHTS methods.
+ *
+ * If the C library implements posix_fallocate(), it is used to
+ * guarantee that disk space is available for the file at the
+ * given size. If disk space is insufficent, errno is set to ENOSPC.
+ * If posix_fallocate() is not supported, program may receive
+ * SIGBUS on accessing mmap()'ed file contents instead.
*/
int
os_create_anonymous_file(off_t size)
const char *path;
char *name;
int fd;
+ int ret;
path = getenv("XDG_RUNTIME_DIR");
if (!path) {
if (fd < 0)
return -1;
- if (ftruncate(fd, size) < 0) {
+#ifdef HAVE_POSIX_FALLOCATE
+ ret = posix_fallocate(fd, 0, size);
+ if (ret != 0) {
+ close(fd);
+ errno = ret;
+ return -1;
+ }
+#else
+ ret = ftruncate(fd, size);
+ if (ret < 0) {
close(fd);
return -1;
}
+#endif
return fd;
}