On 7/31/15 4:59 AM, Kaixu Xia wrote:
+static int check_func_limit(struct bpf_map **mapp, int func_id)
+{
+ struct bpf_map *map = *mapp;
+
+ if (map && map->map_type == BPF_MAP_TYPE_PROG_ARRAY &&
+ func_id != BPF_FUNC_tail_call)
+ /* prog_array map type needs extra care:
+ * only allow to pass it into bpf_tail_call() for now.
+ * bpf_map_delete_elem() can be allowed in the future,
+ * while bpf_map_update_elem() must only be done via syscall
+ */
+ return -EINVAL;
+
+ if (func_id == BPF_FUNC_tail_call &&
+ map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
+ /* don't allow any other map type to be passed into
+ * bpf_tail_call()
+ */
+ return -EINVAL;
+
+ if (map && map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
+ func_id != BPF_FUNC_perf_event_read)
+ /* perf_event_array map type needs extra care:
+ * only allow to pass it into bpf_perf_event_read() for now.
+ * bpf_map_update/delete_elem() must only be done via syscall
+ */
+ return -EINVAL;
+
+ if (func_id == BPF_FUNC_perf_event_read &&
+ map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
+ /* don't allow any other map type to be passed into
+ * bpf_perf_event_read()
+ */
+ return -EINVAL;
copy paste of comments is too much.
The whole thing probably can be better generalized with an array
{{BPF_MAP_TYPE_PROG_ARRAY, BPF_FUNC_tail_call},
{BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_FUNC_perf_event_read},
}
and a loop?
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