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

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

__u64 uprobe_multi_func_1_addr = 0;
__u64 uprobe_multi_func_2_addr = 0;
__u64 uprobe_multi_func_3_addr = 0;

__u64 uprobe_multi_func_1_result = 0;
__u64 uprobe_multi_func_2_result = 0;
__u64 uprobe_multi_func_3_result = 0;

__u64 uretprobe_multi_func_1_result = 0;
__u64 uretprobe_multi_func_2_result = 0;
__u64 uretprobe_multi_func_3_result = 0;

__u64 uprobe_multi_sleep_result = 0;

int pid = 0;
int child_pid = 0;
int child_tid = 0;
int child_pid_usdt = 0;
int child_tid_usdt = 0;

int expect_pid = 0;
bool bad_pid_seen = false;
bool bad_pid_seen_usdt = false;

bool test_cookie = false;
void *user_ptr = 0;

static __always_inline bool verify_sleepable_user_copy(void)
{
        char data[9];

        bpf_copy_from_user(data, sizeof(data), user_ptr);
        return bpf_strncmp(data, sizeof(data), "test_data") == 0;
}

static void uprobe_multi_check(void *ctx, bool is_return, bool is_sleep)
{
        __u64 cur_pid_tgid = bpf_get_current_pid_tgid();
        __u32 cur_pid;

        cur_pid = cur_pid_tgid >> 32;
        if (pid && cur_pid != pid)
                return;

        if (expect_pid && cur_pid != expect_pid)
                bad_pid_seen = true;

        child_pid = cur_pid_tgid >> 32;
        child_tid = (__u32)cur_pid_tgid;

        __u64 cookie = test_cookie ? bpf_get_attach_cookie(ctx) : 0;
        __u64 addr = bpf_get_func_ip(ctx);

#define SET(__var, __addr, __cookie) ({                 \
        if (addr == __addr &&                           \
           (!test_cookie || (cookie == __cookie)))      \
                __var += 1;                             \
})

        if (is_return) {
                SET(uretprobe_multi_func_1_result, uprobe_multi_func_1_addr, 2);
                SET(uretprobe_multi_func_2_result, uprobe_multi_func_2_addr, 3);
                SET(uretprobe_multi_func_3_result, uprobe_multi_func_3_addr, 1);
        } else {
                SET(uprobe_multi_func_1_result, uprobe_multi_func_1_addr, 3);
                SET(uprobe_multi_func_2_result, uprobe_multi_func_2_addr, 1);
                SET(uprobe_multi_func_3_result, uprobe_multi_func_3_addr, 2);
        }

#undef SET

        if (is_sleep && verify_sleepable_user_copy())
                uprobe_multi_sleep_result += 1;
}

SEC("uprobe.multi//proc/self/exe:uprobe_multi_func_*")
int uprobe(struct pt_regs *ctx)
{
        uprobe_multi_check(ctx, false, false);
        return 0;
}

SEC("uretprobe.multi//proc/self/exe:uprobe_multi_func_*")
int uretprobe(struct pt_regs *ctx)
{
        uprobe_multi_check(ctx, true, false);
        return 0;
}

SEC("uprobe.multi.s//proc/self/exe:uprobe_multi_func_*")
int uprobe_sleep(struct pt_regs *ctx)
{
        uprobe_multi_check(ctx, false, true);
        return 0;
}

SEC("uretprobe.multi.s//proc/self/exe:uprobe_multi_func_*")
int uretprobe_sleep(struct pt_regs *ctx)
{
        uprobe_multi_check(ctx, true, true);
        return 0;
}

SEC("uprobe.multi//proc/self/exe:uprobe_multi_func_*")
int uprobe_extra(struct pt_regs *ctx)
{
        /* we need this one just to mix PID-filtered and global uprobes */
        return 0;
}

SEC("usdt")
int usdt_pid(struct pt_regs *ctx)
{
        __u64 cur_pid_tgid = bpf_get_current_pid_tgid();
        __u32 cur_pid;

        cur_pid = cur_pid_tgid >> 32;
        if (pid && cur_pid != pid)
                return 0;

        if (expect_pid && cur_pid != expect_pid)
                bad_pid_seen_usdt = true;

        child_pid_usdt = cur_pid_tgid >> 32;
        child_tid_usdt = (__u32)cur_pid_tgid;

        return 0;
}

SEC("usdt")
int usdt_extra(struct pt_regs *ctx)
{
        /* we need this one just to mix PID-filtered and global USDT probes */
        return 0;
}