// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)

/*
 * common eBPF ELF operations.
 *
 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
 * Copyright (C) 2015 Huawei Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License (not later!)
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not,  see <http://www.gnu.org/licenses>
 */

#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <errno.h>
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/kernel.h>
#include <limits.h>
#include <sys/resource.h>
#include "bpf.h"
#include "libbpf.h"
#include "libbpf_internal.h"

/*
 * When building perf, unistd.h is overridden. __NR_bpf is
 * required to be defined explicitly.
 */
#ifndef __NR_bpf
# if defined(__i386__)
#  define __NR_bpf 357
# elif defined(__x86_64__)
#  define __NR_bpf 321
# elif defined(__aarch64__)
#  define __NR_bpf 280
# elif defined(__sparc__)
#  define __NR_bpf 349
# elif defined(__s390__)
#  define __NR_bpf 351
# elif defined(__arc__)
#  define __NR_bpf 280
# elif defined(__mips__) && defined(_ABIO32)
#  define __NR_bpf 4355
# elif defined(__mips__) && defined(_ABIN32)
#  define __NR_bpf 6319
# elif defined(__mips__) && defined(_ABI64)
#  define __NR_bpf 5315
# else
#  error __NR_bpf not defined. libbpf does not support your arch.
# endif
#endif

static inline __u64 ptr_to_u64(const void *ptr)
{
        return (__u64) (unsigned long) ptr;
}

static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
                          unsigned int size)
{
        return syscall(__NR_bpf, cmd, attr, size);
}

static inline int sys_bpf_fd(enum bpf_cmd cmd, union bpf_attr *attr,
                             unsigned int size)
{
        int fd;

        fd = sys_bpf(cmd, attr, size);
        return ensure_good_fd(fd);
}

#define PROG_LOAD_ATTEMPTS 5

static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts)
{
        int fd;

        do {
                fd = sys_bpf_fd(BPF_PROG_LOAD, attr, size);
        } while (fd < 0 && errno == EAGAIN && --attempts > 0);

        return fd;
}

/* Probe whether kernel switched from memlock-based (RLIMIT_MEMLOCK) to
 * memcg-based memory accounting for BPF maps and progs. This was done in [0].
 * We use the support for bpf_ktime_get_coarse_ns() helper, which was added in
 * the same 5.11 Linux release ([1]), to detect memcg-based accounting for BPF.
 *
 *   [0] https://lore.kernel.org/bpf/20201201215900.3569844-1-guro@fb.com/
 *   [1] d05512618056 ("bpf: Add bpf_ktime_get_coarse_ns helper")
 */
int probe_memcg_account(void)
{
        const size_t prog_load_attr_sz = offsetofend(union bpf_attr, attach_btf_obj_fd);
        struct bpf_insn insns[] = {
                BPF_EMIT_CALL(BPF_FUNC_ktime_get_coarse_ns),
                BPF_EXIT_INSN(),
        };
        size_t insn_cnt = ARRAY_SIZE(insns);
        union bpf_attr attr;
        int prog_fd;

        /* attempt loading freplace trying to use custom BTF */
        memset(&attr, 0, prog_load_attr_sz);
        attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
        attr.insns = ptr_to_u64(insns);
        attr.insn_cnt = insn_cnt;
        attr.license = ptr_to_u64("GPL");

        prog_fd = sys_bpf_fd(BPF_PROG_LOAD, &attr, prog_load_attr_sz);
        if (prog_fd >= 0) {
                close(prog_fd);
                return 1;
        }
        return 0;
}

static bool memlock_bumped;
static rlim_t memlock_rlim = RLIM_INFINITY;

int libbpf_set_memlock_rlim(size_t memlock_bytes)
{
        if (memlock_bumped)
                return libbpf_err(-EBUSY);

        memlock_rlim = memlock_bytes;
        return 0;
}

int bump_rlimit_memlock(void)
{
        struct rlimit rlim;

        /* this the default in libbpf 1.0, but for now user has to opt-in explicitly */
        if (!(libbpf_mode & LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK))
                return 0;

        /* if kernel supports memcg-based accounting, skip bumping RLIMIT_MEMLOCK */
        if (memlock_bumped || kernel_supports(NULL, FEAT_MEMCG_ACCOUNT))
                return 0;

        memlock_bumped = true;

        /* zero memlock_rlim_max disables auto-bumping RLIMIT_MEMLOCK */
        if (memlock_rlim == 0)
                return 0;

        rlim.rlim_cur = rlim.rlim_max = memlock_rlim;
        if (setrlimit(RLIMIT_MEMLOCK, &rlim))
                return -errno;

        return 0;
}

int bpf_map_create(enum bpf_map_type map_type,
                   const char *map_name,
                   __u32 key_size,
                   __u32 value_size,
                   __u32 max_entries,
                   const struct bpf_map_create_opts *opts)
{
        const size_t attr_sz = offsetofend(union bpf_attr, map_extra);
        union bpf_attr attr;
        int fd;

        bump_rlimit_memlock();

        memset(&attr, 0, attr_sz);

        if (!OPTS_VALID(opts, bpf_map_create_opts))
                return libbpf_err(-EINVAL);

        attr.map_type = map_type;
        if (map_name)
                libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name));
        attr.key_size = key_size;
        attr.value_size = value_size;
        attr.max_entries = max_entries;

        attr.btf_fd = OPTS_GET(opts, btf_fd, 0);
        attr.btf_key_type_id = OPTS_GET(opts, btf_key_type_id, 0);
        attr.btf_value_type_id = OPTS_GET(opts, btf_value_type_id, 0);
        attr.btf_vmlinux_value_type_id = OPTS_GET(opts, btf_vmlinux_value_type_id, 0);

        attr.inner_map_fd = OPTS_GET(opts, inner_map_fd, 0);
        attr.map_flags = OPTS_GET(opts, map_flags, 0);
        attr.map_extra = OPTS_GET(opts, map_extra, 0);
        attr.numa_node = OPTS_GET(opts, numa_node, 0);
        attr.map_ifindex = OPTS_GET(opts, map_ifindex, 0);

        fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
        return libbpf_err_errno(fd);
}

static void *
alloc_zero_tailing_info(const void *orecord, __u32 cnt,
                        __u32 actual_rec_size, __u32 expected_rec_size)
{
        __u64 info_len = (__u64)actual_rec_size * cnt;
        void *info, *nrecord;
        int i;

        info = malloc(info_len);
        if (!info)
                return NULL;

        /* zero out bytes kernel does not understand */
        nrecord = info;
        for (i = 0; i < cnt; i++) {
                memcpy(nrecord, orecord, expected_rec_size);
                memset(nrecord + expected_rec_size, 0,
                       actual_rec_size - expected_rec_size);
                orecord += actual_rec_size;
                nrecord += actual_rec_size;
        }

        return info;
}

DEFAULT_VERSION(bpf_prog_load_v0_6_0, bpf_prog_load, LIBBPF_0.6.0)
int bpf_prog_load_v0_6_0(enum bpf_prog_type prog_type,
                         const char *prog_name, const char *license,
                         const struct bpf_insn *insns, size_t insn_cnt,
                         const struct bpf_prog_load_opts *opts)
{
        void *finfo = NULL, *linfo = NULL;
        const char *func_info, *line_info;
        __u32 log_size, log_level, attach_prog_fd, attach_btf_obj_fd;
        __u32 func_info_rec_size, line_info_rec_size;
        int fd, attempts;
        union bpf_attr attr;
        char *log_buf;

        bump_rlimit_memlock();

        if (!OPTS_VALID(opts, bpf_prog_load_opts))
                return libbpf_err(-EINVAL);

        attempts = OPTS_GET(opts, attempts, 0);
        if (attempts < 0)
                return libbpf_err(-EINVAL);
        if (attempts == 0)
                attempts = PROG_LOAD_ATTEMPTS;

        memset(&attr, 0, sizeof(attr));

        attr.prog_type = prog_type;
        attr.expected_attach_type = OPTS_GET(opts, expected_attach_type, 0);

        attr.prog_btf_fd = OPTS_GET(opts, prog_btf_fd, 0);
        attr.prog_flags = OPTS_GET(opts, prog_flags, 0);
        attr.prog_ifindex = OPTS_GET(opts, prog_ifindex, 0);
        attr.kern_version = OPTS_GET(opts, kern_version, 0);

        if (prog_name)
                libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name));
        attr.license = ptr_to_u64(license);

        if (insn_cnt > UINT_MAX)
                return libbpf_err(-E2BIG);

        attr.insns = ptr_to_u64(insns);
        attr.insn_cnt = (__u32)insn_cnt;

        attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
        attach_btf_obj_fd = OPTS_GET(opts, attach_btf_obj_fd, 0);

        if (attach_prog_fd && attach_btf_obj_fd)
                return libbpf_err(-EINVAL);

        attr.attach_btf_id = OPTS_GET(opts, attach_btf_id, 0);
        if (attach_prog_fd)
                attr.attach_prog_fd = attach_prog_fd;
        else
                attr.attach_btf_obj_fd = attach_btf_obj_fd;

        log_buf = OPTS_GET(opts, log_buf, NULL);
        log_size = OPTS_GET(opts, log_size, 0);
        log_level = OPTS_GET(opts, log_level, 0);

        if (!!log_buf != !!log_size)
                return libbpf_err(-EINVAL);
        if (log_level > (4 | 2 | 1))
                return libbpf_err(-EINVAL);
        if (log_level && !log_buf)
                return libbpf_err(-EINVAL);

        func_info_rec_size = OPTS_GET(opts, func_info_rec_size, 0);
        func_info = OPTS_GET(opts, func_info, NULL);
        attr.func_info_rec_size = func_info_rec_size;
        attr.func_info = ptr_to_u64(func_info);
        attr.func_info_cnt = OPTS_GET(opts, func_info_cnt, 0);

        line_info_rec_size = OPTS_GET(opts, line_info_rec_size, 0);
        line_info = OPTS_GET(opts, line_info, NULL);
        attr.line_info_rec_size = line_info_rec_size;
        attr.line_info = ptr_to_u64(line_info);
        attr.line_info_cnt = OPTS_GET(opts, line_info_cnt, 0);

        attr.fd_array = ptr_to_u64(OPTS_GET(opts, fd_array, NULL));

        if (log_level) {
                attr.log_buf = ptr_to_u64(log_buf);
                attr.log_size = log_size;
                attr.log_level = log_level;
        }

        fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
        if (fd >= 0)
                return fd;

        /* After bpf_prog_load, the kernel may modify certain attributes
         * to give user space a hint how to deal with loading failure.
         * Check to see whether we can make some changes and load again.
         */
        while (errno == E2BIG && (!finfo || !linfo)) {
                if (!finfo && attr.func_info_cnt &&
                    attr.func_info_rec_size < func_info_rec_size) {
                        /* try with corrected func info records */
                        finfo = alloc_zero_tailing_info(func_info,
                                                        attr.func_info_cnt,
                                                        func_info_rec_size,
                                                        attr.func_info_rec_size);
                        if (!finfo) {
                                errno = E2BIG;
                                goto done;
                        }

                        attr.func_info = ptr_to_u64(finfo);
                        attr.func_info_rec_size = func_info_rec_size;
                } else if (!linfo && attr.line_info_cnt &&
                           attr.line_info_rec_size < line_info_rec_size) {
                        linfo = alloc_zero_tailing_info(line_info,
                                                        attr.line_info_cnt,
                                                        line_info_rec_size,
                                                        attr.line_info_rec_size);
                        if (!linfo) {
                                errno = E2BIG;
                                goto done;
                        }

                        attr.line_info = ptr_to_u64(linfo);
                        attr.line_info_rec_size = line_info_rec_size;
                } else {
                        break;
                }

                fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
                if (fd >= 0)
                        goto done;
        }

        if (log_level == 0 && log_buf) {
                /* log_level == 0 with non-NULL log_buf requires retrying on error
                 * with log_level == 1 and log_buf/log_buf_size set, to get details of
                 * failure
                 */
                attr.log_buf = ptr_to_u64(log_buf);
                attr.log_size = log_size;
                attr.log_level = 1;

                fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
        }
done:
        /* free() doesn't affect errno, so we don't need to restore it */
        free(finfo);
        free(linfo);
        return libbpf_err_errno(fd);
}

__attribute__((alias("bpf_load_program_xattr2")))
int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
                           char *log_buf, size_t log_buf_sz);

static int bpf_load_program_xattr2(const struct bpf_load_program_attr *load_attr,
                                   char *log_buf, size_t log_buf_sz)
{
        LIBBPF_OPTS(bpf_prog_load_opts, p);

        if (!load_attr || !log_buf != !log_buf_sz)
                return libbpf_err(-EINVAL);

        p.expected_attach_type = load_attr->expected_attach_type;
        switch (load_attr->prog_type) {
        case BPF_PROG_TYPE_STRUCT_OPS:
        case BPF_PROG_TYPE_LSM:
                p.attach_btf_id = load_attr->attach_btf_id;
                break;
        case BPF_PROG_TYPE_TRACING:
        case BPF_PROG_TYPE_EXT:
                p.attach_btf_id = load_attr->attach_btf_id;
                p.attach_prog_fd = load_attr->attach_prog_fd;
                break;
        default:
                p.prog_ifindex = load_attr->prog_ifindex;
                p.kern_version = load_attr->kern_version;
        }
        p.log_level = load_attr->log_level;
        p.log_buf = log_buf;
        p.log_size = log_buf_sz;
        p.prog_btf_fd = load_attr->prog_btf_fd;
        p.func_info_rec_size = load_attr->func_info_rec_size;
        p.func_info_cnt = load_attr->func_info_cnt;
        p.func_info = load_attr->func_info;
        p.line_info_rec_size = load_attr->line_info_rec_size;
        p.line_info_cnt = load_attr->line_info_cnt;
        p.line_info = load_attr->line_info;
        p.prog_flags = load_attr->prog_flags;

        return bpf_prog_load(load_attr->prog_type, load_attr->name, load_attr->license,
                             load_attr->insns, load_attr->insns_cnt, &p);
}

int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
                     size_t insns_cnt, const char *license,
                     __u32 kern_version, char *log_buf,
                     size_t log_buf_sz)
{
        struct bpf_load_program_attr load_attr;

        memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
        load_attr.prog_type = type;
        load_attr.expected_attach_type = 0;
        load_attr.name = NULL;
        load_attr.insns = insns;
        load_attr.insns_cnt = insns_cnt;
        load_attr.license = license;
        load_attr.kern_version = kern_version;

        return bpf_load_program_xattr2(&load_attr, log_buf, log_buf_sz);
}

int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
                       size_t insns_cnt, __u32 prog_flags, const char *license,
                       __u32 kern_version, char *log_buf, size_t log_buf_sz,
                       int log_level)
{
        union bpf_attr attr;
        int fd;

        bump_rlimit_memlock();

        memset(&attr, 0, sizeof(attr));
        attr.prog_type = type;
        attr.insn_cnt = (__u32)insns_cnt;
        attr.insns = ptr_to_u64(insns);
        attr.license = ptr_to_u64(license);
        attr.log_buf = ptr_to_u64(log_buf);
        attr.log_size = log_buf_sz;
        attr.log_level = log_level;
        log_buf[0] = 0;
        attr.kern_version = kern_version;
        attr.prog_flags = prog_flags;

        fd = sys_bpf_prog_load(&attr, sizeof(attr), PROG_LOAD_ATTEMPTS);
        return libbpf_err_errno(fd);
}

int bpf_map_update_elem(int fd, const void *key, const void *value,
                        __u64 flags)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
        attr.flags = flags;

        ret = sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_lookup_elem(int fd, const void *key, void *value)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);

        ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
        attr.flags = flags;

        ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);

        ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_lookup_and_delete_elem_flags(int fd, const void *key, void *value, __u64 flags)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
        attr.flags = flags;

        ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_delete_elem(int fd, const void *key)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);

        ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_delete_elem_flags(int fd, const void *key, __u64 flags)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.flags = flags;

        ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_get_next_key(int fd, const void *key, void *next_key)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.next_key = ptr_to_u64(next_key);

        ret = sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_map_freeze(int fd)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.map_fd = fd;

        ret = sys_bpf(BPF_MAP_FREEZE, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

static int bpf_map_batch_common(int cmd, int fd, void  *in_batch,
                                void *out_batch, void *keys, void *values,
                                __u32 *count,
                                const struct bpf_map_batch_opts *opts)
{
        union bpf_attr attr;
        int ret;

        if (!OPTS_VALID(opts, bpf_map_batch_opts))
                return libbpf_err(-EINVAL);

        memset(&attr, 0, sizeof(attr));
        attr.batch.map_fd = fd;
        attr.batch.in_batch = ptr_to_u64(in_batch);
        attr.batch.out_batch = ptr_to_u64(out_batch);
        attr.batch.keys = ptr_to_u64(keys);
        attr.batch.values = ptr_to_u64(values);
        attr.batch.count = *count;
        attr.batch.elem_flags  = OPTS_GET(opts, elem_flags, 0);
        attr.batch.flags = OPTS_GET(opts, flags, 0);

        ret = sys_bpf(cmd, &attr, sizeof(attr));
        *count = attr.batch.count;

        return libbpf_err_errno(ret);
}

int bpf_map_delete_batch(int fd, const void *keys, __u32 *count,
                         const struct bpf_map_batch_opts *opts)
{
        return bpf_map_batch_common(BPF_MAP_DELETE_BATCH, fd, NULL,
                                    NULL, (void *)keys, NULL, count, opts);
}

int bpf_map_lookup_batch(int fd, void *in_batch, void *out_batch, void *keys,
                         void *values, __u32 *count,
                         const struct bpf_map_batch_opts *opts)
{
        return bpf_map_batch_common(BPF_MAP_LOOKUP_BATCH, fd, in_batch,
                                    out_batch, keys, values, count, opts);
}

int bpf_map_lookup_and_delete_batch(int fd, void *in_batch, void *out_batch,
                                    void *keys, void *values, __u32 *count,
                                    const struct bpf_map_batch_opts *opts)
{
        return bpf_map_batch_common(BPF_MAP_LOOKUP_AND_DELETE_BATCH,
                                    fd, in_batch, out_batch, keys, values,
                                    count, opts);
}

int bpf_map_update_batch(int fd, const void *keys, const void *values, __u32 *count,
                         const struct bpf_map_batch_opts *opts)
{
        return bpf_map_batch_common(BPF_MAP_UPDATE_BATCH, fd, NULL, NULL,
                                    (void *)keys, (void *)values, count, opts);
}

int bpf_obj_pin(int fd, const char *pathname)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.pathname = ptr_to_u64((void *)pathname);
        attr.bpf_fd = fd;

        ret = sys_bpf(BPF_OBJ_PIN, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_obj_get(const char *pathname)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.pathname = ptr_to_u64((void *)pathname);

        fd = sys_bpf_fd(BPF_OBJ_GET, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
                    unsigned int flags)
{
        DECLARE_LIBBPF_OPTS(bpf_prog_attach_opts, opts,
                .flags = flags,
        );

        return bpf_prog_attach_opts(prog_fd, target_fd, type, &opts);
}

int bpf_prog_attach_opts(int prog_fd, int target_fd,
                          enum bpf_attach_type type,
                          const struct bpf_prog_attach_opts *opts)
{
        union bpf_attr attr;
        int ret;

        if (!OPTS_VALID(opts, bpf_prog_attach_opts))
                return libbpf_err(-EINVAL);

        memset(&attr, 0, sizeof(attr));
        attr.target_fd     = target_fd;
        attr.attach_bpf_fd = prog_fd;
        attr.attach_type   = type;
        attr.attach_flags  = OPTS_GET(opts, flags, 0);
        attr.replace_bpf_fd = OPTS_GET(opts, replace_prog_fd, 0);

        ret = sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

__attribute__((alias("bpf_prog_attach_opts")))
int bpf_prog_attach_xattr(int prog_fd, int target_fd,
                          enum bpf_attach_type type,
                          const struct bpf_prog_attach_opts *opts);

int bpf_prog_detach(int target_fd, enum bpf_attach_type type)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.target_fd   = target_fd;
        attr.attach_type = type;

        ret = sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.target_fd   = target_fd;
        attr.attach_bpf_fd = prog_fd;
        attr.attach_type = type;

        ret = sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_link_create(int prog_fd, int target_fd,
                    enum bpf_attach_type attach_type,
                    const struct bpf_link_create_opts *opts)
{
        __u32 target_btf_id, iter_info_len;
        union bpf_attr attr;
        int fd, err;

        if (!OPTS_VALID(opts, bpf_link_create_opts))
                return libbpf_err(-EINVAL);

        iter_info_len = OPTS_GET(opts, iter_info_len, 0);
        target_btf_id = OPTS_GET(opts, target_btf_id, 0);

        /* validate we don't have unexpected combinations of non-zero fields */
        if (iter_info_len || target_btf_id) {
                if (iter_info_len && target_btf_id)
                        return libbpf_err(-EINVAL);
                if (!OPTS_ZEROED(opts, target_btf_id))
                        return libbpf_err(-EINVAL);
        }

        memset(&attr, 0, sizeof(attr));
        attr.link_create.prog_fd = prog_fd;
        attr.link_create.target_fd = target_fd;
        attr.link_create.attach_type = attach_type;
        attr.link_create.flags = OPTS_GET(opts, flags, 0);

        if (target_btf_id) {
                attr.link_create.target_btf_id = target_btf_id;
                goto proceed;
        }

        switch (attach_type) {
        case BPF_TRACE_ITER:
                attr.link_create.iter_info = ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0));
                attr.link_create.iter_info_len = iter_info_len;
                break;
        case BPF_PERF_EVENT:
                attr.link_create.perf_event.bpf_cookie = OPTS_GET(opts, perf_event.bpf_cookie, 0);
                if (!OPTS_ZEROED(opts, perf_event))
                        return libbpf_err(-EINVAL);
                break;
        case BPF_TRACE_KPROBE_MULTI:
                attr.link_create.kprobe_multi.flags = OPTS_GET(opts, kprobe_multi.flags, 0);
                attr.link_create.kprobe_multi.cnt = OPTS_GET(opts, kprobe_multi.cnt, 0);
                attr.link_create.kprobe_multi.syms = ptr_to_u64(OPTS_GET(opts, kprobe_multi.syms, 0));
                attr.link_create.kprobe_multi.addrs = ptr_to_u64(OPTS_GET(opts, kprobe_multi.addrs, 0));
                attr.link_create.kprobe_multi.cookies = ptr_to_u64(OPTS_GET(opts, kprobe_multi.cookies, 0));
                if (!OPTS_ZEROED(opts, kprobe_multi))
                        return libbpf_err(-EINVAL);
                break;
        case BPF_TRACE_FENTRY:
        case BPF_TRACE_FEXIT:
        case BPF_MODIFY_RETURN:
        case BPF_LSM_MAC:
                attr.link_create.tracing.cookie = OPTS_GET(opts, tracing.cookie, 0);
                if (!OPTS_ZEROED(opts, tracing))
                        return libbpf_err(-EINVAL);
                break;
        default:
                if (!OPTS_ZEROED(opts, flags))
                        return libbpf_err(-EINVAL);
                break;
        }
proceed:
        fd = sys_bpf_fd(BPF_LINK_CREATE, &attr, sizeof(attr));
        if (fd >= 0)
                return fd;
        /* we'll get EINVAL if LINK_CREATE doesn't support attaching fentry
         * and other similar programs
         */
        err = -errno;
        if (err != -EINVAL)
                return libbpf_err(err);

        /* if user used features not supported by
         * BPF_RAW_TRACEPOINT_OPEN command, then just give up immediately
         */
        if (attr.link_create.target_fd || attr.link_create.target_btf_id)
                return libbpf_err(err);
        if (!OPTS_ZEROED(opts, sz))
                return libbpf_err(err);

        /* otherwise, for few select kinds of programs that can be
         * attached using BPF_RAW_TRACEPOINT_OPEN command, try that as
         * a fallback for older kernels
         */
        switch (attach_type) {
        case BPF_TRACE_RAW_TP:
        case BPF_LSM_MAC:
        case BPF_TRACE_FENTRY:
        case BPF_TRACE_FEXIT:
        case BPF_MODIFY_RETURN:
                return bpf_raw_tracepoint_open(NULL, prog_fd);
        default:
                return libbpf_err(err);
        }
}

int bpf_link_detach(int link_fd)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.link_detach.link_fd = link_fd;

        ret = sys_bpf(BPF_LINK_DETACH, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_link_update(int link_fd, int new_prog_fd,
                    const struct bpf_link_update_opts *opts)
{
        union bpf_attr attr;
        int ret;

        if (!OPTS_VALID(opts, bpf_link_update_opts))
                return libbpf_err(-EINVAL);

        memset(&attr, 0, sizeof(attr));
        attr.link_update.link_fd = link_fd;
        attr.link_update.new_prog_fd = new_prog_fd;
        attr.link_update.flags = OPTS_GET(opts, flags, 0);
        attr.link_update.old_prog_fd = OPTS_GET(opts, old_prog_fd, 0);

        ret = sys_bpf(BPF_LINK_UPDATE, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}

int bpf_iter_create(int link_fd)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.iter_create.link_fd = link_fd;

        fd = sys_bpf_fd(BPF_ITER_CREATE, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
                   __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.query.target_fd    = target_fd;
        attr.query.attach_type  = type;
        attr.query.query_flags  = query_flags;
        attr.query.prog_cnt     = *prog_cnt;
        attr.query.prog_ids     = ptr_to_u64(prog_ids);

        ret = sys_bpf(BPF_PROG_QUERY, &attr, sizeof(attr));

        if (attach_flags)
                *attach_flags = attr.query.attach_flags;
        *prog_cnt = attr.query.prog_cnt;

        return libbpf_err_errno(ret);
}

int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
                      void *data_out, __u32 *size_out, __u32 *retval,
                      __u32 *duration)
{
        union bpf_attr attr;
        int ret;

        memset(&attr, 0, sizeof(attr));
        attr.test.prog_fd = prog_fd;
        attr.test.data_in = ptr_to_u64(data);
        attr.test.data_out = ptr_to_u64(data_out);
        attr.test.data_size_in = size;
        attr.test.repeat = repeat;

        ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));

        if (size_out)
                *size_out = attr.test.data_size_out;
        if (retval)
                *retval = attr.test.retval;
        if (duration)
                *duration = attr.test.duration;

        return libbpf_err_errno(ret);
}

int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
{
        union bpf_attr attr;
        int ret;

        if (!test_attr->data_out && test_attr->data_size_out > 0)
                return libbpf_err(-EINVAL);

        memset(&attr, 0, sizeof(attr));
        attr.test.prog_fd = test_attr->prog_fd;
        attr.test.data_in = ptr_to_u64(test_attr->data_in);
        attr.test.data_out = ptr_to_u64(test_attr->data_out);
        attr.test.data_size_in = test_attr->data_size_in;
        attr.test.data_size_out = test_attr->data_size_out;
        attr.test.ctx_in = ptr_to_u64(test_attr->ctx_in);
        attr.test.ctx_out = ptr_to_u64(test_attr->ctx_out);
        attr.test.ctx_size_in = test_attr->ctx_size_in;
        attr.test.ctx_size_out = test_attr->ctx_size_out;
        attr.test.repeat = test_attr->repeat;

        ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));

        test_attr->data_size_out = attr.test.data_size_out;
        test_attr->ctx_size_out = attr.test.ctx_size_out;
        test_attr->retval = attr.test.retval;
        test_attr->duration = attr.test.duration;

        return libbpf_err_errno(ret);
}

int bpf_prog_test_run_opts(int prog_fd, struct bpf_test_run_opts *opts)
{
        union bpf_attr attr;
        int ret;

        if (!OPTS_VALID(opts, bpf_test_run_opts))
                return libbpf_err(-EINVAL);

        memset(&attr, 0, sizeof(attr));
        attr.test.prog_fd = prog_fd;
        attr.test.batch_size = OPTS_GET(opts, batch_size, 0);
        attr.test.cpu = OPTS_GET(opts, cpu, 0);
        attr.test.flags = OPTS_GET(opts, flags, 0);
        attr.test.repeat = OPTS_GET(opts, repeat, 0);
        attr.test.duration = OPTS_GET(opts, duration, 0);
        attr.test.ctx_size_in = OPTS_GET(opts, ctx_size_in, 0);
        attr.test.ctx_size_out = OPTS_GET(opts, ctx_size_out, 0);
        attr.test.data_size_in = OPTS_GET(opts, data_size_in, 0);
        attr.test.data_size_out = OPTS_GET(opts, data_size_out, 0);
        attr.test.ctx_in = ptr_to_u64(OPTS_GET(opts, ctx_in, NULL));
        attr.test.ctx_out = ptr_to_u64(OPTS_GET(opts, ctx_out, NULL));
        attr.test.data_in = ptr_to_u64(OPTS_GET(opts, data_in, NULL));
        attr.test.data_out = ptr_to_u64(OPTS_GET(opts, data_out, NULL));

        ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));

        OPTS_SET(opts, data_size_out, attr.test.data_size_out);
        OPTS_SET(opts, ctx_size_out, attr.test.ctx_size_out);
        OPTS_SET(opts, duration, attr.test.duration);
        OPTS_SET(opts, retval, attr.test.retval);

        return libbpf_err_errno(ret);

}

static int bpf_obj_get_next_id(__u32 start_id, __u32 *next_id, int cmd)
{
        union bpf_attr attr;
        int err;

        memset(&attr, 0, sizeof(attr));
        attr.start_id = start_id;

        err = sys_bpf(cmd, &attr, sizeof(attr));
        if (!err)
                *next_id = attr.next_id;

        return libbpf_err_errno(err);
}

int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id)
{
        return bpf_obj_get_next_id(start_id, next_id, BPF_PROG_GET_NEXT_ID);
}

int bpf_map_get_next_id(__u32 start_id, __u32 *next_id)
{
        return bpf_obj_get_next_id(start_id, next_id, BPF_MAP_GET_NEXT_ID);
}

int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id)
{
        return bpf_obj_get_next_id(start_id, next_id, BPF_BTF_GET_NEXT_ID);
}

int bpf_link_get_next_id(__u32 start_id, __u32 *next_id)
{
        return bpf_obj_get_next_id(start_id, next_id, BPF_LINK_GET_NEXT_ID);
}

int bpf_prog_get_fd_by_id(__u32 id)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.prog_id = id;

        fd = sys_bpf_fd(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_map_get_fd_by_id(__u32 id)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.map_id = id;

        fd = sys_bpf_fd(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_btf_get_fd_by_id(__u32 id)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.btf_id = id;

        fd = sys_bpf_fd(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_link_get_fd_by_id(__u32 id)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.link_id = id;

        fd = sys_bpf_fd(BPF_LINK_GET_FD_BY_ID, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len)
{
        union bpf_attr attr;
        int err;

        memset(&attr, 0, sizeof(attr));
        attr.info.bpf_fd = bpf_fd;
        attr.info.info_len = *info_len;
        attr.info.info = ptr_to_u64(info);

        err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr));

        if (!err)
                *info_len = attr.info.info_len;

        return libbpf_err_errno(err);
}

int bpf_raw_tracepoint_open(const char *name, int prog_fd)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.raw_tracepoint.name = ptr_to_u64(name);
        attr.raw_tracepoint.prog_fd = prog_fd;

        fd = sys_bpf_fd(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_btf_load(const void *btf_data, size_t btf_size, const struct bpf_btf_load_opts *opts)
{
        const size_t attr_sz = offsetofend(union bpf_attr, btf_log_level);
        union bpf_attr attr;
        char *log_buf;
        size_t log_size;
        __u32 log_level;
        int fd;

        bump_rlimit_memlock();

        memset(&attr, 0, attr_sz);

        if (!OPTS_VALID(opts, bpf_btf_load_opts))
                return libbpf_err(-EINVAL);

        log_buf = OPTS_GET(opts, log_buf, NULL);
        log_size = OPTS_GET(opts, log_size, 0);
        log_level = OPTS_GET(opts, log_level, 0);

        if (log_size > UINT_MAX)
                return libbpf_err(-EINVAL);
        if (log_size && !log_buf)
                return libbpf_err(-EINVAL);

        attr.btf = ptr_to_u64(btf_data);
        attr.btf_size = btf_size;
        /* log_level == 0 and log_buf != NULL means "try loading without
         * log_buf, but retry with log_buf and log_level=1 on error", which is
         * consistent across low-level and high-level BTF and program loading
         * APIs within libbpf and provides a sensible behavior in practice
         */
        if (log_level) {
                attr.btf_log_buf = ptr_to_u64(log_buf);
                attr.btf_log_size = (__u32)log_size;
                attr.btf_log_level = log_level;
        }

        fd = sys_bpf_fd(BPF_BTF_LOAD, &attr, attr_sz);
        if (fd < 0 && log_buf && log_level == 0) {
                attr.btf_log_buf = ptr_to_u64(log_buf);
                attr.btf_log_size = (__u32)log_size;
                attr.btf_log_level = 1;
                fd = sys_bpf_fd(BPF_BTF_LOAD, &attr, attr_sz);
        }
        return libbpf_err_errno(fd);
}

int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size, bool do_log)
{
        LIBBPF_OPTS(bpf_btf_load_opts, opts);
        int fd;

retry:
        if (do_log && log_buf && log_buf_size) {
                opts.log_buf = log_buf;
                opts.log_size = log_buf_size;
                opts.log_level = 1;
        }

        fd = bpf_btf_load(btf, btf_size, &opts);
        if (fd < 0 && !do_log && log_buf && log_buf_size) {
                do_log = true;
                goto retry;
        }

        return libbpf_err_errno(fd);
}

int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
                      __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
                      __u64 *probe_addr)
{
        union bpf_attr attr = {};
        int err;

        attr.task_fd_query.pid = pid;
        attr.task_fd_query.fd = fd;
        attr.task_fd_query.flags = flags;
        attr.task_fd_query.buf = ptr_to_u64(buf);
        attr.task_fd_query.buf_len = *buf_len;

        err = sys_bpf(BPF_TASK_FD_QUERY, &attr, sizeof(attr));

        *buf_len = attr.task_fd_query.buf_len;
        *prog_id = attr.task_fd_query.prog_id;
        *fd_type = attr.task_fd_query.fd_type;
        *probe_offset = attr.task_fd_query.probe_offset;
        *probe_addr = attr.task_fd_query.probe_addr;

        return libbpf_err_errno(err);
}

int bpf_enable_stats(enum bpf_stats_type type)
{
        union bpf_attr attr;
        int fd;

        memset(&attr, 0, sizeof(attr));
        attr.enable_stats.type = type;

        fd = sys_bpf_fd(BPF_ENABLE_STATS, &attr, sizeof(attr));
        return libbpf_err_errno(fd);
}

int bpf_prog_bind_map(int prog_fd, int map_fd,
                      const struct bpf_prog_bind_opts *opts)
{
        union bpf_attr attr;
        int ret;

        if (!OPTS_VALID(opts, bpf_prog_bind_opts))
                return libbpf_err(-EINVAL);

        memset(&attr, 0, sizeof(attr));
        attr.prog_bind_map.prog_fd = prog_fd;
        attr.prog_bind_map.map_fd = map_fd;
        attr.prog_bind_map.flags = OPTS_GET(opts, flags, 0);

        ret = sys_bpf(BPF_PROG_BIND_MAP, &attr, sizeof(attr));
        return libbpf_err_errno(ret);
}