// SPDX-License-Identifier: GPL-2.0
#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include "bpf_experimental.h"
#include "bpf_misc.h"

struct node_data {
        long key;
        long data;
        struct bpf_rb_node node;
};

#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
private(A) struct bpf_spin_lock glock;
private(A) struct bpf_rb_root groot __contains(node_data, node);
private(A) struct bpf_rb_root groot2 __contains(node_data, node);

static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
        struct node_data *node_a;
        struct node_data *node_b;

        node_a = container_of(a, struct node_data, node);
        node_b = container_of(b, struct node_data, node);

        return node_a->key < node_b->key;
}

SEC("?tc")
__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")
long rbtree_api_nolock_add(void *ctx)
{
        struct node_data *n;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;

        bpf_rbtree_add(&groot, &n->node, less);
        return 0;
}

SEC("?tc")
__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")
long rbtree_api_nolock_remove(void *ctx)
{
        struct node_data *n;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, less);
        bpf_spin_unlock(&glock);

        bpf_rbtree_remove(&groot, &n->node);
        return 0;
}

SEC("?tc")
__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")
long rbtree_api_nolock_first(void *ctx)
{
        bpf_rbtree_first(&groot);
        return 0;
}

SEC("?tc")
__retval(0)
long rbtree_api_remove_unadded_node(void *ctx)
{
        struct node_data *n, *m;
        struct bpf_rb_node *res_n, *res_m;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;

        m = bpf_obj_new(typeof(*m));
        if (!m) {
                bpf_obj_drop(n);
                return 1;
        }

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, less);

        res_n = bpf_rbtree_remove(&groot, &n->node);

        res_m = bpf_rbtree_remove(&groot, &m->node);
        bpf_spin_unlock(&glock);

        bpf_obj_drop(m);
        if (res_n)
                bpf_obj_drop(container_of(res_n, struct node_data, node));
        if (res_m) {
                bpf_obj_drop(container_of(res_m, struct node_data, node));
                /* m was not added to the rbtree */
                return 2;
        }

        return 0;
}

SEC("?tc")
__failure __msg("Unreleased reference id=3 alloc_insn={{[0-9]+}}")
long rbtree_api_remove_no_drop(void *ctx)
{
        struct bpf_rb_node *res;
        struct node_data *n;

        bpf_spin_lock(&glock);
        res = bpf_rbtree_first(&groot);
        if (!res)
                goto unlock_err;

        res = bpf_rbtree_remove(&groot, res);

        if (res) {
                n = container_of(res, struct node_data, node);
                __sink(n);
        }
        bpf_spin_unlock(&glock);

        /* if (res) { bpf_obj_drop(n); } is missing here */
        return 0;

unlock_err:
        bpf_spin_unlock(&glock);
        return 1;
}

SEC("?tc")
__failure __msg("arg#1 expected pointer to allocated object")
long rbtree_api_add_to_multiple_trees(void *ctx)
{
        struct node_data *n;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, less);

        /* This add should fail since n already in groot's tree */
        bpf_rbtree_add(&groot2, &n->node, less);
        bpf_spin_unlock(&glock);
        return 0;
}

SEC("?tc")
__failure __msg("Possibly NULL pointer passed to trusted arg1")
long rbtree_api_use_unchecked_remove_retval(void *ctx)
{
        struct bpf_rb_node *res;

        bpf_spin_lock(&glock);

        res = bpf_rbtree_first(&groot);
        if (!res)
                goto err_out;
        res = bpf_rbtree_remove(&groot, res);

        bpf_spin_unlock(&glock);

        bpf_spin_lock(&glock);
        /* Must check res for NULL before using in rbtree_add below */
        bpf_rbtree_add(&groot, res, less);
        bpf_spin_unlock(&glock);
        return 0;

err_out:
        bpf_spin_unlock(&glock);
        return 1;
}

SEC("?tc")
__failure __msg("bpf_rbtree_remove can only take non-owning or refcounted bpf_rb_node pointer")
long rbtree_api_add_release_unlock_escape(void *ctx)
{
        struct node_data *n;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, less);
        bpf_spin_unlock(&glock);

        bpf_spin_lock(&glock);
        /* After add() in previous critical section, n should be
         * release_on_unlock and released after previous spin_unlock,
         * so should not be possible to use it here
         */
        bpf_rbtree_remove(&groot, &n->node);
        bpf_spin_unlock(&glock);
        return 0;
}

SEC("?tc")
__failure __msg("bpf_rbtree_remove can only take non-owning or refcounted bpf_rb_node pointer")
long rbtree_api_first_release_unlock_escape(void *ctx)
{
        struct bpf_rb_node *res;
        struct node_data *n;

        bpf_spin_lock(&glock);
        res = bpf_rbtree_first(&groot);
        if (!res) {
                bpf_spin_unlock(&glock);
                return 1;
        }
        n = container_of(res, struct node_data, node);
        bpf_spin_unlock(&glock);

        bpf_spin_lock(&glock);
        /* After first() in previous critical section, n should be
         * release_on_unlock and released after previous spin_unlock,
         * so should not be possible to use it here
         */
        bpf_rbtree_remove(&groot, &n->node);
        bpf_spin_unlock(&glock);
        return 0;
}

static bool less__bad_fn_call_add(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
        struct node_data *node_a;
        struct node_data *node_b;

        node_a = container_of(a, struct node_data, node);
        node_b = container_of(b, struct node_data, node);
        bpf_rbtree_add(&groot, &node_a->node, less);

        return node_a->key < node_b->key;
}

static bool less__bad_fn_call_remove(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
        struct node_data *node_a;
        struct node_data *node_b;

        node_a = container_of(a, struct node_data, node);
        node_b = container_of(b, struct node_data, node);
        bpf_rbtree_remove(&groot, &node_a->node);

        return node_a->key < node_b->key;
}

static bool less__bad_fn_call_first_unlock_after(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
        struct node_data *node_a;
        struct node_data *node_b;

        node_a = container_of(a, struct node_data, node);
        node_b = container_of(b, struct node_data, node);
        bpf_rbtree_first(&groot);
        bpf_spin_unlock(&glock);

        return node_a->key < node_b->key;
}

static __always_inline
long add_with_cb(bool (cb)(struct bpf_rb_node *a, const struct bpf_rb_node *b))
{
        struct node_data *n;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, cb);
        bpf_spin_unlock(&glock);
        return 0;
}

SEC("?tc")
__failure __msg("arg#1 expected pointer to allocated object")
long rbtree_api_add_bad_cb_bad_fn_call_add(void *ctx)
{
        return add_with_cb(less__bad_fn_call_add);
}

SEC("?tc")
__failure __msg("rbtree_remove not allowed in rbtree cb")
long rbtree_api_add_bad_cb_bad_fn_call_remove(void *ctx)
{
        return add_with_cb(less__bad_fn_call_remove);
}

SEC("?tc")
__failure __msg("can't spin_{lock,unlock} in rbtree cb")
long rbtree_api_add_bad_cb_bad_fn_call_first_unlock_after(void *ctx)
{
        return add_with_cb(less__bad_fn_call_first_unlock_after);
}

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