+#define alignof(t) offsetof(struct { char c; t x; }, x)
+
+#define W 1
+#define R 2
+#define WR 3
+
+struct ioctl_compat_map {
+ int new_req, old_req, old_size;
+ char dir, force_align;
+ int offsets[4];
+};
+
+static const struct ioctl_compat_map compat_map[] = {
+ { SIOCGSTAMP, SIOCGSTAMP_OLD, 8, R, 0, { 0, -1, -1, -1 } },
+ { SIOCGSTAMPNS, SIOCGSTAMPNS_OLD, 8, R, 0, { 0, -1, -1, -1 } },
+};
+
+static void convert_ioctl_struct(const struct ioctl_compat_map *map, char *old, char *new, int dir)
+{
+ int new_offset = 0;
+ int old_offset = 0;
+ int old_size = map->old_size;
+ if (!(dir & map->dir)) return;
+ for (int i=0; i < sizeof map->offsets / sizeof *map->offsets; i++) {
+ int ts_offset = map->offsets[i];
+ if (ts_offset < 0) break;
+ int len = ts_offset-old_offset;
+ if (dir==W) memcpy(old+old_offset, new+new_offset, len);
+ else memcpy(new+new_offset, old+old_offset, len);
+ new_offset += len;
+ old_offset += len;
+ long long new_ts[2];
+ long old_ts[2];
+ int align = map->force_align ? sizeof(time_t) : alignof(time_t);
+ new_offset += (align-1) & -new_offset;
+ if (dir==W) {
+ memcpy(new_ts, new+new_offset, sizeof new_ts);
+ old_ts[0] = new_ts[0];
+ old_ts[1] = new_ts[1];
+ memcpy(old+old_offset, old_ts, sizeof old_ts);
+ } else {
+ memcpy(old_ts, old+old_offset, sizeof old_ts);
+ new_ts[0] = old_ts[0];
+ new_ts[1] = old_ts[1];
+ memcpy(new+new_offset, new_ts, sizeof new_ts);
+ }
+ new_offset += sizeof new_ts;
+ old_offset += sizeof old_ts;
+ }
+ if (dir==W) memcpy(old+old_offset, new+new_offset, old_size-old_offset);
+ else memcpy(new+new_offset, old+old_offset, old_size-old_offset);
+}
+