// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>

char _license[] SEC("license") = "GPL";

struct key_t {
        int a;
        int b;
        int c;
};

struct {
        __uint(type, BPF_MAP_TYPE_HASH);
        __uint(max_entries, 3);
        __type(key, struct key_t);
        __type(value, __u64);
} hashmap1 SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_HASH);
        __uint(max_entries, 3);
        __type(key, __u64);
        __type(value, __u64);
} hashmap2 SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_HASH);
        __uint(max_entries, 3);
        __type(key, struct key_t);
        __type(value, __u32);
} hashmap3 SEC(".maps");

/* will set before prog run */
bool in_test_mode = 0;

/* will collect results during prog run */
__u32 key_sum_a = 0, key_sum_b = 0, key_sum_c = 0;
__u64 val_sum = 0;

SEC("iter/bpf_map_elem")
int dump_bpf_hash_map(struct bpf_iter__bpf_map_elem *ctx)
{
        struct seq_file *seq = ctx->meta->seq;
        __u32 seq_num = ctx->meta->seq_num;
        struct bpf_map *map = ctx->map;
        struct key_t *key = ctx->key;
        struct key_t tmp_key;
        __u64 *val = ctx->value;
        __u64 tmp_val = 0;
        int ret;

        if (in_test_mode) {
                /* test mode is used by selftests to
                 * test functionality of bpf_hash_map iter.
                 *
                 * the above hashmap1 will have correct size
                 * and will be accepted, hashmap2 and hashmap3
                 * should be rejected due to smaller key/value
                 * size.
                 */
                if (key == (void *)0 || val == (void *)0)
                        return 0;

                /* update the value and then delete the <key, value> pair.
                 * it should not impact the existing 'val' which is still
                 * accessible under rcu.
                 */
                __builtin_memcpy(&tmp_key, key, sizeof(struct key_t));
                ret = bpf_map_update_elem(&hashmap1, &tmp_key, &tmp_val, 0);
                if (ret)
                        return 0;
                ret = bpf_map_delete_elem(&hashmap1, &tmp_key);
                if (ret)
                        return 0;

                key_sum_a += key->a;
                key_sum_b += key->b;
                key_sum_c += key->c;
                val_sum += *val;
                return 0;
        }

        /* non-test mode, the map is prepared with the
         * below bpftool command sequence:
         *   bpftool map create /sys/fs/bpf/m1 type hash \
         *      key 12 value 8 entries 3 name map1
         *   bpftool map update id 77 key 0 0 0 1 0 0 0 0 0 0 0 1 \
         *      value 0 0 0 1 0 0 0 1
         *   bpftool map update id 77 key 0 0 0 1 0 0 0 0 0 0 0 2 \
         *      value 0 0 0 1 0 0 0 2
         * The bpftool iter command line:
         *   bpftool iter pin ./bpf_iter_bpf_hash_map.o /sys/fs/bpf/p1 \
         *      map id 77
         * The below output will be:
         *   map dump starts
         *   77: (1000000 0 2000000) (200000001000000)
         *   77: (1000000 0 1000000) (100000001000000)
         *   map dump ends
         */
        if (seq_num == 0)
                BPF_SEQ_PRINTF(seq, "map dump starts\n");

        if (key == (void *)0 || val == (void *)0) {
                BPF_SEQ_PRINTF(seq, "map dump ends\n");
                return 0;
        }

        BPF_SEQ_PRINTF(seq, "%d: (%x %d %x) (%llx)\n", map->id,
                       key->a, key->b, key->c, *val);

        return 0;
}

SEC("iter.s/bpf_map_elem")
int sleepable_dummy_dump(struct bpf_iter__bpf_map_elem *ctx)
{
        if (ctx->meta->seq_num == 0)
                BPF_SEQ_PRINTF(ctx->meta->seq, "map dump starts\n");

        return 0;
}