// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020, Oracle and/or its affiliates. */

#include "btf_ptr.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>
#include "bpf_misc.h"

#include <errno.h>

long ret = 0;
int num_subtests = 0;
int ran_subtests = 0;
bool skip = false;

#define STRSIZE                 2048
#define EXPECTED_STRSIZE        256

#if defined(bpf_target_s390)
/* NULL points to a readable struct lowcore on s390, so take the last page */
#define BADPTR                  ((void *)0xFFFFFFFFFFFFF000ULL)
#else
#define BADPTR                  0
#endif

struct {
        __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
        __uint(max_entries, 1);
        __type(key, __u32);
        __type(value, char[STRSIZE]);
} strdata SEC(".maps");

static int __strncmp(const void *m1, const void *m2, size_t len)
{
        const unsigned char *s1 = m1;
        const unsigned char *s2 = m2;
        int i, delta = 0;

        for (i = 0; i < len; i++) {
                delta = s1[i] - s2[i];
                if (delta || s1[i] == 0 || s2[i] == 0)
                        break;
        }
        return delta;
}

#if __has_builtin(__builtin_btf_type_id)
#define TEST_BTF(_str, _type, _flags, _expected, ...)                   \
        do {                                                            \
                static const char _expectedval[EXPECTED_STRSIZE] =      \
                                                        _expected;      \
                __u64 _hflags = _flags | BTF_F_COMPACT;                 \
                static _type _ptrdata = __VA_ARGS__;                    \
                static struct btf_ptr _ptr = { };                       \
                int _cmp;                                               \
                                                                        \
                ++num_subtests;                                         \
                if (ret < 0)                                            \
                        break;                                          \
                ++ran_subtests;                                         \
                _ptr.ptr = &_ptrdata;                                   \
                _ptr.type_id = bpf_core_type_id_kernel(_type);          \
                if (_ptr.type_id <= 0) {                                \
                        ret = -EINVAL;                                  \
                        break;                                          \
                }                                                       \
                ret = bpf_snprintf_btf(_str, STRSIZE,                   \
                                       &_ptr, sizeof(_ptr), _hflags);   \
                if (ret)                                                \
                        break;                                          \
                _cmp = __strncmp(_str, _expectedval, EXPECTED_STRSIZE); \
                if (_cmp != 0) {                                        \
                        bpf_printk("(%d) got %s", _cmp, _str);          \
                        bpf_printk("(%d) expected %s", _cmp,            \
                                   _expectedval);                       \
                        ret = -EBADMSG;                                 \
                        break;                                          \
                }                                                       \
        } while (0)
#endif

/* Use where expected data string matches its stringified declaration */
#define TEST_BTF_C(_str, _type, _flags, ...)                            \
        TEST_BTF(_str, _type, _flags, "(" #_type ")" #__VA_ARGS__,      \
                 __VA_ARGS__)

/* TRACE_EVENT(netif_receive_skb,
 *      TP_PROTO(struct sk_buff *skb),
 */
SEC("tp_btf/netif_receive_skb")
int BPF_PROG(trace_netif_receive_skb, struct sk_buff *skb)
{
        static __u64 flags[] = { 0, BTF_F_COMPACT, BTF_F_ZERO, BTF_F_PTR_RAW,
                                 BTF_F_NONAME, BTF_F_COMPACT | BTF_F_ZERO |
                                 BTF_F_PTR_RAW | BTF_F_NONAME };
        static struct btf_ptr p = { };
        __u32 key = 0;
        int i, __ret;
        char *str;

#if __has_builtin(__builtin_btf_type_id)
        str = bpf_map_lookup_elem(&strdata, &key);
        if (!str)
                return 0;

        /* Ensure we can write skb string representation */
        p.type_id = bpf_core_type_id_kernel(struct sk_buff);
        p.ptr = skb;
        for (i = 0; i < ARRAY_SIZE(flags); i++) {
                ++num_subtests;
                ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
                if (ret < 0)
                        bpf_printk("returned %d when writing skb", ret);
                ++ran_subtests;
        }

        /* Check invalid ptr value */
        p.ptr = BADPTR;
        __ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
        if (__ret >= 0) {
                bpf_printk("printing %llx should generate error, got (%d)",
                           (unsigned long long)BADPTR, __ret);
                ret = -ERANGE;
        }

        /* Verify type display for various types. */

        /* simple int */
        TEST_BTF_C(str, int, 0, 1234);
        TEST_BTF(str, int, BTF_F_NONAME, "1234", 1234);
        /* zero value should be printed at toplevel */
        TEST_BTF(str, int, 0, "(int)0", 0);
        TEST_BTF(str, int, BTF_F_NONAME, "0", 0);
        TEST_BTF(str, int, BTF_F_ZERO, "(int)0", 0);
        TEST_BTF(str, int, BTF_F_NONAME | BTF_F_ZERO, "0", 0);
        TEST_BTF_C(str, int, 0, -4567);
        TEST_BTF(str, int, BTF_F_NONAME, "-4567", -4567);

        /* simple char */
        TEST_BTF_C(str, char, 0, 100);
        TEST_BTF(str, char, BTF_F_NONAME, "100", 100);
        /* zero value should be printed at toplevel */
        TEST_BTF(str, char, 0, "(char)0", 0);
        TEST_BTF(str, char, BTF_F_NONAME, "0", 0);
        TEST_BTF(str, char, BTF_F_ZERO, "(char)0", 0);
        TEST_BTF(str, char, BTF_F_NONAME | BTF_F_ZERO, "0", 0);

        /* simple typedef */
        TEST_BTF_C(str, uint64_t, 0, 100);
        TEST_BTF(str, u64, BTF_F_NONAME, "1", 1);
        /* zero value should be printed at toplevel */
        TEST_BTF(str, u64, 0, "(u64)0", 0);
        TEST_BTF(str, u64, BTF_F_NONAME, "0", 0);
        TEST_BTF(str, u64, BTF_F_ZERO, "(u64)0", 0);
        TEST_BTF(str, u64, BTF_F_NONAME|BTF_F_ZERO, "0", 0);

        /* typedef struct */
        TEST_BTF_C(str, atomic_t, 0, {.counter = (int)1,});
        TEST_BTF(str, atomic_t, BTF_F_NONAME, "{1,}", {.counter = 1,});
        /* typedef with 0 value should be printed at toplevel */
        TEST_BTF(str, atomic_t, 0, "(atomic_t){}", {.counter = 0,});
        TEST_BTF(str, atomic_t, BTF_F_NONAME, "{}", {.counter = 0,});
        TEST_BTF(str, atomic_t, BTF_F_ZERO, "(atomic_t){.counter = (int)0,}",
                 {.counter = 0,});
        TEST_BTF(str, atomic_t, BTF_F_NONAME|BTF_F_ZERO,
                 "{0,}", {.counter = 0,});

        /* enum where enum value does (and does not) exist */
        TEST_BTF_C(str, enum bpf_cmd, 0, BPF_MAP_CREATE);
        TEST_BTF(str, enum bpf_cmd, 0, "(enum bpf_cmd)BPF_MAP_CREATE", 0);
        TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "BPF_MAP_CREATE",
                 BPF_MAP_CREATE);
        TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO,
                 "BPF_MAP_CREATE", 0);

        TEST_BTF(str, enum bpf_cmd, BTF_F_ZERO, "(enum bpf_cmd)BPF_MAP_CREATE",
                 BPF_MAP_CREATE);
        TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO,
                 "BPF_MAP_CREATE", BPF_MAP_CREATE);
        TEST_BTF_C(str, enum bpf_cmd, 0, 2000);
        TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "2000", 2000);

        /* simple struct */
        TEST_BTF_C(str, struct btf_enum, 0,
                   {.name_off = (__u32)3,.val = (__s32)-1,});
        TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{3,-1,}",
                 { .name_off = 3, .val = -1,});
        TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{-1,}",
                 { .name_off = 0, .val = -1,});
        TEST_BTF(str, struct btf_enum, BTF_F_NONAME|BTF_F_ZERO, "{0,-1,}",
                 { .name_off = 0, .val = -1,});
        /* empty struct should be printed */
        TEST_BTF(str, struct btf_enum, 0, "(struct btf_enum){}",
                 { .name_off = 0, .val = 0,});
        TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{}",
                 { .name_off = 0, .val = 0,});
        TEST_BTF(str, struct btf_enum, BTF_F_ZERO,
                 "(struct btf_enum){.name_off = (__u32)0,.val = (__s32)0,}",
                 { .name_off = 0, .val = 0,});

        /* struct with pointers */
        TEST_BTF(str, struct list_head, BTF_F_PTR_RAW,
                 "(struct list_head){.next = (struct list_head *)0x0000000000000001,}",
                 { .next = (struct list_head *)1 });
        /* NULL pointer should not be displayed */
        TEST_BTF(str, struct list_head, BTF_F_PTR_RAW,
                 "(struct list_head){}",
                 { .next = (struct list_head *)0 });

        /* struct with char array */
        TEST_BTF(str, struct bpf_prog_info, 0,
                 "(struct bpf_prog_info){.name = (char[])['f','o','o',],}",
                 { .name = "foo",});
        TEST_BTF(str, struct bpf_prog_info, BTF_F_NONAME,
                 "{['f','o','o',],}",
                 {.name = "foo",});
        /* leading null char means do not display string */
        TEST_BTF(str, struct bpf_prog_info, 0,
                 "(struct bpf_prog_info){}",
                 {.name = {'\0', 'f', 'o', 'o'}});
        /* handle non-printable characters */
        TEST_BTF(str, struct bpf_prog_info, 0,
                 "(struct bpf_prog_info){.name = (char[])[1,2,3,],}",
                 { .name = {1, 2, 3, 0}});

        /* struct with non-char array */
        TEST_BTF(str, struct __sk_buff, 0,
                 "(struct __sk_buff){.cb = (__u32[])[1,2,3,4,5,],}",
                 { .cb = {1, 2, 3, 4, 5,},});
        TEST_BTF(str, struct __sk_buff, BTF_F_NONAME,
                 "{[1,2,3,4,5,],}",
                 { .cb = { 1, 2, 3, 4, 5},});
        /* For non-char, arrays, show non-zero values only */
        TEST_BTF(str, struct __sk_buff, 0,
                 "(struct __sk_buff){.cb = (__u32[])[1,],}",
                 { .cb = { 0, 0, 1, 0, 0},});

        /* struct with bitfields */
        TEST_BTF_C(str, struct bpf_insn, 0,
                   {.code = (__u8)1,.dst_reg = (__u8)0x2,.src_reg = (__u8)0x3,.off = (__s16)4,.imm = (__s32)5,});
        TEST_BTF(str, struct bpf_insn, BTF_F_NONAME, "{1,0x2,0x3,4,5,}",
                 {.code = 1, .dst_reg = 0x2, .src_reg = 0x3, .off = 4,
                  .imm = 5,});
#else
        skip = true;
#endif

        return 0;
}

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