#include <bpf/libbpf.h>
#include <internal/xyarray.h>

#include "util/debug.h"
#include "util/evlist.h"
#include "util/trace_augment.h"

#include "bpf_skel/augmented_raw_syscalls.skel.h"

static struct augmented_raw_syscalls_bpf *skel;
static struct evsel *bpf_output;

int augmented_syscalls__prepare(void)
{
        struct bpf_program *prog;
        char buf[128];
        int err;

        skel = augmented_raw_syscalls_bpf__open();
        if (!skel) {
                pr_debug("Failed to open augmented syscalls BPF skeleton\n");
                return -errno;
        }

        /*
         * Disable attaching the BPF programs except for sys_enter and
         * sys_exit that tail call into this as necessary.
         */
        bpf_object__for_each_program(prog, skel->obj) {
                if (prog != skel->progs.sys_enter && prog != skel->progs.sys_exit)
                        bpf_program__set_autoattach(prog, /*autoattach=*/false);
        }

        err = augmented_raw_syscalls_bpf__load(skel);
        if (err < 0) {
                libbpf_strerror(err, buf, sizeof(buf));
                pr_debug("Failed to load augmented syscalls BPF skeleton: %s\n", buf);
                return err;
        }

        augmented_raw_syscalls_bpf__attach(skel);
        return 0;
}

int augmented_syscalls__create_bpf_output(struct evlist *evlist)
{
        int err = parse_event(evlist, "bpf-output/no-inherit=1,name=__augmented_syscalls__/");

        if (err) {
                pr_err("ERROR: Setup BPF output event failed: %d\n", err);
                return err;
        }

        bpf_output = evlist__last(evlist);
        assert(evsel__name_is(bpf_output, "__augmented_syscalls__"));

        return 0;
}

void augmented_syscalls__setup_bpf_output(void)
{
        struct perf_cpu cpu;
        int i;

        if (bpf_output == NULL)
                return;

        /*
         * Set up the __augmented_syscalls__ BPF map to hold for each
         * CPU the bpf-output event's file descriptor.
         */
        perf_cpu_map__for_each_cpu(cpu, i, bpf_output->core.cpus) {
                int mycpu = cpu.cpu;

                bpf_map__update_elem(skel->maps.__augmented_syscalls__,
                                     &mycpu, sizeof(mycpu),
                                     xyarray__entry(bpf_output->core.fd,
                                                    mycpu, 0),
                                     sizeof(__u32), BPF_ANY);
        }
}

int augmented_syscalls__set_filter_pids(unsigned int nr, pid_t *pids)
{
        bool value = true;
        int err = 0;

        if (skel == NULL)
                return 0;

        for (size_t i = 0; i < nr; ++i) {
                err = bpf_map__update_elem(skel->maps.pids_filtered, &pids[i],
                                           sizeof(*pids), &value, sizeof(value),
                                           BPF_ANY);
                if (err)
                        break;
        }
        return err;
}

int augmented_syscalls__get_map_fds(int *enter_fd, int *exit_fd, int *beauty_fd)
{
        if (skel == NULL)
                return -1;

        *enter_fd = bpf_map__fd(skel->maps.syscalls_sys_enter);
        *exit_fd  = bpf_map__fd(skel->maps.syscalls_sys_exit);
        *beauty_fd = bpf_map__fd(skel->maps.beauty_map_enter);

        if (*enter_fd < 0 || *exit_fd < 0 || *beauty_fd < 0) {
                pr_err("Error: failed to get syscall or beauty map fd\n");
                return -1;
        }

        return 0;
}

struct bpf_program *augmented_syscalls__unaugmented(void)
{
        return skel->progs.syscall_unaugmented;
}

struct bpf_program *augmented_syscalls__find_by_title(const char *name)
{
        struct bpf_program *pos;
        const char *sec_name;

        if (skel->obj == NULL)
                return NULL;

        bpf_object__for_each_program(pos, skel->obj) {
                sec_name = bpf_program__section_name(pos);
                if (sec_name && !strcmp(sec_name, name))
                        return pos;
        }

        return NULL;
}

void augmented_syscalls__cleanup(void)
{
        augmented_raw_syscalls_bpf__destroy(skel);
}