root/tools/bpf/bpftool/common.c
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2017-2018 Netronome Systems, Inc. */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <ftw.h>
#include <libgen.h>
#include <mntent.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/mount.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/vfs.h>
#include <sys/utsname.h>

#include <linux/filter.h>
#include <linux/limits.h>
#include <linux/magic.h>
#include <linux/unistd.h>

#include <bpf/bpf.h>
#include <bpf/hashmap.h>
#include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
#include <bpf/btf.h>
#include <zlib.h>

#include "main.h"

#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC            0xcafe4a11
#endif

void p_err(const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        if (json_output) {
                jsonw_start_object(json_wtr);
                jsonw_name(json_wtr, "error");
                jsonw_vprintf_enquote(json_wtr, fmt, ap);
                jsonw_end_object(json_wtr);
        } else {
                fprintf(stderr, "Error: ");
                vfprintf(stderr, fmt, ap);
                fprintf(stderr, "\n");
        }
        va_end(ap);
}

void p_info(const char *fmt, ...)
{
        va_list ap;

        if (json_output)
                return;

        va_start(ap, fmt);
        vfprintf(stderr, fmt, ap);
        fprintf(stderr, "\n");
        va_end(ap);
}

static bool is_bpffs(const char *path)
{
        struct statfs st_fs;

        if (statfs(path, &st_fs) < 0)
                return false;

        return (unsigned long)st_fs.f_type == BPF_FS_MAGIC;
}

/* Probe whether kernel switched from memlock-based (RLIMIT_MEMLOCK) to
 * memcg-based memory accounting for BPF maps and programs. This was done in
 * commit 97306be45fbe ("Merge branch 'switch to memcg-based memory
 * accounting'"), in Linux 5.11.
 *
 * Libbpf also offers to probe for memcg-based accounting vs rlimit, but does
 * so by checking for the availability of a given BPF helper and this has
 * failed on some kernels with backports in the past, see commit 6b4384ff1088
 * ("Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"").
 * Instead, we can probe by lowering the process-based rlimit to 0, trying to
 * load a BPF object, and resetting the rlimit. If the load succeeds then
 * memcg-based accounting is supported.
 *
 * This would be too dangerous to do in the library, because multithreaded
 * applications might attempt to load items while the rlimit is at 0. Given
 * that bpftool is single-threaded, this is fine to do here.
 */
static bool known_to_need_rlimit(void)
{
        struct rlimit rlim_init, rlim_cur_zero = {};
        struct bpf_insn insns[] = {
                BPF_MOV64_IMM(BPF_REG_0, 0),
                BPF_EXIT_INSN(),
        };
        size_t insn_cnt = ARRAY_SIZE(insns);
        union bpf_attr attr;
        int prog_fd, err;

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

        if (getrlimit(RLIMIT_MEMLOCK, &rlim_init))
                return false;

        /* Drop the soft limit to zero. We maintain the hard limit to its
         * current value, because lowering it would be a permanent operation
         * for unprivileged users.
         */
        rlim_cur_zero.rlim_max = rlim_init.rlim_max;
        if (setrlimit(RLIMIT_MEMLOCK, &rlim_cur_zero))
                return false;

        /* Do not use bpf_prog_load() from libbpf here, because it calls
         * bump_rlimit_memlock(), interfering with the current probe.
         */
        prog_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
        err = errno;

        /* reset soft rlimit to its initial value */
        setrlimit(RLIMIT_MEMLOCK, &rlim_init);

        if (prog_fd < 0)
                return err == EPERM;

        close(prog_fd);
        return false;
}

void set_max_rlimit(void)
{
        struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };

        if (known_to_need_rlimit())
                setrlimit(RLIMIT_MEMLOCK, &rinf);
}

static int
mnt_fs(const char *target, const char *type, char *buff, size_t bufflen)
{
        bool bind_done = false;

        while (mount("", target, "none", MS_PRIVATE | MS_REC, NULL)) {
                if (errno != EINVAL || bind_done) {
                        snprintf(buff, bufflen,
                                 "mount --make-private %s failed: %s",
                                 target, strerror(errno));
                        return -1;
                }

                if (mount(target, target, "none", MS_BIND, NULL)) {
                        snprintf(buff, bufflen,
                                 "mount --bind %s %s failed: %s",
                                 target, target, strerror(errno));
                        return -1;
                }

                bind_done = true;
        }

        if (mount(type, target, type, 0, "mode=0700")) {
                snprintf(buff, bufflen, "mount -t %s %s %s failed: %s",
                         type, type, target, strerror(errno));
                return -1;
        }

        return 0;
}

int mount_tracefs(const char *target)
{
        char err_str[ERR_MAX_LEN];
        int err;

        err = mnt_fs(target, "tracefs", err_str, ERR_MAX_LEN);
        if (err) {
                err_str[ERR_MAX_LEN - 1] = '\0';
                p_err("can't mount tracefs: %s", err_str);
        }

        return err;
}

int open_obj_pinned(const char *path, bool quiet,
                    const struct bpf_obj_get_opts *opts)
{
        char *pname;
        int fd = -1;

        pname = strdup(path);
        if (!pname) {
                if (!quiet)
                        p_err("mem alloc failed");
                goto out_ret;
        }

        fd = bpf_obj_get_opts(pname, opts);
        if (fd < 0) {
                if (!quiet)
                        p_err("bpf obj get (%s): %s", pname,
                              errno == EACCES && !is_bpffs(dirname(pname)) ?
                            "directory not in bpf file system (bpffs)" :
                            strerror(errno));
                goto out_free;
        }

out_free:
        free(pname);
out_ret:
        return fd;
}

int open_obj_pinned_any(const char *path, enum bpf_obj_type exp_type,
                        const struct bpf_obj_get_opts *opts)
{
        enum bpf_obj_type type;
        int fd;

        fd = open_obj_pinned(path, false, opts);
        if (fd < 0)
                return -1;

        type = get_fd_type(fd);
        if (type < 0) {
                close(fd);
                return type;
        }
        if (type != exp_type) {
                p_err("incorrect object type: %s", get_fd_type_name(type));
                close(fd);
                return -1;
        }

        return fd;
}

int create_and_mount_bpffs_dir(const char *dir_name)
{
        char err_str[ERR_MAX_LEN];
        bool dir_exists;
        int err = 0;

        if (is_bpffs(dir_name))
                return err;

        dir_exists = access(dir_name, F_OK) == 0;

        if (!dir_exists) {
                char *temp_name;
                char *parent_name;

                temp_name = strdup(dir_name);
                if (!temp_name) {
                        p_err("mem alloc failed");
                        return -1;
                }

                parent_name = dirname(temp_name);

                if (is_bpffs(parent_name)) {
                        /* nothing to do if already mounted */
                        free(temp_name);
                        return err;
                }

                if (access(parent_name, F_OK) == -1) {
                        p_err("can't create dir '%s' to pin BPF object: parent dir '%s' doesn't exist",
                              dir_name, parent_name);
                        free(temp_name);
                        return -1;
                }

                free(temp_name);
        }

        if (block_mount) {
                p_err("no BPF file system found, not mounting it due to --nomount option");
                return -1;
        }

        if (!dir_exists) {
                err = mkdir(dir_name, S_IRWXU);
                if (err) {
                        p_err("failed to create dir '%s': %s", dir_name, strerror(errno));
                        return err;
                }
        }

        err = mnt_fs(dir_name, "bpf", err_str, ERR_MAX_LEN);
        if (err) {
                err_str[ERR_MAX_LEN - 1] = '\0';
                p_err("can't mount BPF file system on given dir '%s': %s",
                      dir_name, err_str);

                if (!dir_exists)
                        rmdir(dir_name);
        }

        return err;
}

int mount_bpffs_for_file(const char *file_name)
{
        char err_str[ERR_MAX_LEN];
        char *temp_name;
        char *dir;
        int err = 0;

        if (access(file_name, F_OK) != -1) {
                p_err("can't pin BPF object: path '%s' already exists", file_name);
                return -1;
        }

        temp_name = strdup(file_name);
        if (!temp_name) {
                p_err("mem alloc failed");
                return -1;
        }

        dir = dirname(temp_name);

        if (is_bpffs(dir))
                /* nothing to do if already mounted */
                goto out_free;

        if (access(dir, F_OK) == -1) {
                p_err("can't pin BPF object: dir '%s' doesn't exist", dir);
                err = -1;
                goto out_free;
        }

        if (block_mount) {
                p_err("no BPF file system found, not mounting it due to --nomount option");
                err = -1;
                goto out_free;
        }

        err = mnt_fs(dir, "bpf", err_str, ERR_MAX_LEN);
        if (err) {
                err_str[ERR_MAX_LEN - 1] = '\0';
                p_err("can't mount BPF file system to pin the object '%s': %s",
                      file_name, err_str);
        }

out_free:
        free(temp_name);
        return err;
}

int do_pin_fd(int fd, const char *name)
{
        int err;

        err = mount_bpffs_for_file(name);
        if (err)
                return err;

        err = bpf_obj_pin(fd, name);
        if (err)
                p_err("can't pin the object (%s): %s", name, strerror(errno));

        return err;
}

int do_pin_any(int argc, char **argv, int (*get_fd)(int *, char ***))
{
        int err;
        int fd;

        if (!REQ_ARGS(3))
                return -EINVAL;

        fd = get_fd(&argc, &argv);
        if (fd < 0)
                return fd;

        err = do_pin_fd(fd, *argv);

        close(fd);
        return err;
}

const char *get_fd_type_name(enum bpf_obj_type type)
{
        static const char * const names[] = {
                [BPF_OBJ_UNKNOWN]       = "unknown",
                [BPF_OBJ_PROG]          = "prog",
                [BPF_OBJ_MAP]           = "map",
                [BPF_OBJ_LINK]          = "link",
        };

        if (type < 0 || type >= ARRAY_SIZE(names) || !names[type])
                return names[BPF_OBJ_UNKNOWN];

        return names[type];
}

void get_prog_full_name(const struct bpf_prog_info *prog_info, int prog_fd,
                        char *name_buff, size_t buff_len)
{
        const char *prog_name = prog_info->name;
        const struct btf_type *func_type;
        struct bpf_func_info finfo = {};
        struct bpf_prog_info info = {};
        __u32 info_len = sizeof(info);
        struct btf *prog_btf = NULL;

        if (buff_len <= BPF_OBJ_NAME_LEN ||
            strlen(prog_info->name) < BPF_OBJ_NAME_LEN - 1)
                goto copy_name;

        if (!prog_info->btf_id || prog_info->nr_func_info == 0)
                goto copy_name;

        info.nr_func_info = 1;
        info.func_info_rec_size = prog_info->func_info_rec_size;
        if (info.func_info_rec_size > sizeof(finfo))
                info.func_info_rec_size = sizeof(finfo);
        info.func_info = ptr_to_u64(&finfo);

        if (bpf_prog_get_info_by_fd(prog_fd, &info, &info_len))
                goto copy_name;

        prog_btf = btf__load_from_kernel_by_id(info.btf_id);
        if (!prog_btf)
                goto copy_name;

        func_type = btf__type_by_id(prog_btf, finfo.type_id);
        if (!func_type || !btf_is_func(func_type))
                goto copy_name;

        prog_name = btf__name_by_offset(prog_btf, func_type->name_off);

copy_name:
        snprintf(name_buff, buff_len, "%s", prog_name);

        if (prog_btf)
                btf__free(prog_btf);
}

int get_fd_type(int fd)
{
        char path[PATH_MAX];
        char buf[512];
        ssize_t n;

        snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);

        n = readlink(path, buf, sizeof(buf));
        if (n < 0) {
                p_err("can't read link type: %s", strerror(errno));
                return -1;
        }
        if (n == sizeof(buf)) {
                p_err("can't read link type: path too long!");
                return -1;
        }
        buf[n] = '\0';

        if (strstr(buf, "bpf-map"))
                return BPF_OBJ_MAP;
        else if (strstr(buf, "bpf-prog"))
                return BPF_OBJ_PROG;
        else if (strstr(buf, "bpf-link"))
                return BPF_OBJ_LINK;

        return BPF_OBJ_UNKNOWN;
}

char *get_fdinfo(int fd, const char *key)
{
        char path[PATH_MAX];
        char *line = NULL;
        size_t line_n = 0;
        ssize_t n;
        FILE *fdi;

        snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", fd);

        fdi = fopen(path, "r");
        if (!fdi)
                return NULL;

        while ((n = getline(&line, &line_n, fdi)) > 0) {
                char *value;
                int len;

                if (!strstr(line, key))
                        continue;

                fclose(fdi);

                value = strchr(line, '\t');
                if (!value || !value[1]) {
                        free(line);
                        return NULL;
                }
                value++;

                len = strlen(value);
                memmove(line, value, len);
                line[len - 1] = '\0';

                return line;
        }

        free(line);
        fclose(fdi);
        return NULL;
}

void print_data_json(uint8_t *data, size_t len)
{
        unsigned int i;

        jsonw_start_array(json_wtr);
        for (i = 0; i < len; i++)
                jsonw_printf(json_wtr, "%d", data[i]);
        jsonw_end_array(json_wtr);
}

void print_hex_data_json(uint8_t *data, size_t len)
{
        unsigned int i;

        jsonw_start_array(json_wtr);
        for (i = 0; i < len; i++)
                jsonw_printf(json_wtr, "\"0x%02hhx\"", data[i]);
        jsonw_end_array(json_wtr);
}

/* extra params for nftw cb */
static struct hashmap *build_fn_table;
static enum bpf_obj_type build_fn_type;

static int do_build_table_cb(const char *fpath, const struct stat *sb,
                             int typeflag, struct FTW *ftwbuf)
{
        struct bpf_prog_info pinned_info;
        __u32 len = sizeof(pinned_info);
        enum bpf_obj_type objtype;
        int fd, err = 0;
        char *path;

        if (typeflag != FTW_F)
                goto out_ret;

        fd = open_obj_pinned(fpath, true, NULL);
        if (fd < 0)
                goto out_ret;

        objtype = get_fd_type(fd);
        if (objtype != build_fn_type)
                goto out_close;

        memset(&pinned_info, 0, sizeof(pinned_info));
        if (bpf_prog_get_info_by_fd(fd, &pinned_info, &len))
                goto out_close;

        path = strdup(fpath);
        if (!path) {
                err = -1;
                goto out_close;
        }

        err = hashmap__append(build_fn_table, pinned_info.id, path);
        if (err) {
                p_err("failed to append entry to hashmap for ID %u, path '%s': %s",
                      pinned_info.id, path, strerror(errno));
                free(path);
                goto out_close;
        }

out_close:
        close(fd);
out_ret:
        return err;
}

int build_pinned_obj_table(struct hashmap *tab,
                           enum bpf_obj_type type)
{
        struct mntent *mntent = NULL;
        FILE *mntfile = NULL;
        int flags = FTW_PHYS;
        int nopenfd = 16;
        int err = 0;

        mntfile = setmntent("/proc/mounts", "r");
        if (!mntfile)
                return -1;

        build_fn_table = tab;
        build_fn_type = type;

        while ((mntent = getmntent(mntfile))) {
                char *path = mntent->mnt_dir;

                if (strncmp(mntent->mnt_type, "bpf", 3) != 0)
                        continue;
                err = nftw(path, do_build_table_cb, nopenfd, flags);
                if (err)
                        break;
        }
        fclose(mntfile);
        return err;
}

void delete_pinned_obj_table(struct hashmap *map)
{
        struct hashmap_entry *entry;
        size_t bkt;

        if (!map)
                return;

        hashmap__for_each_entry(map, entry, bkt)
                free(entry->pvalue);

        hashmap__free(map);
}

unsigned int get_page_size(void)
{
        static int result;

        if (!result)
                result = getpagesize();
        return result;
}

unsigned int get_possible_cpus(void)
{
        int cpus = libbpf_num_possible_cpus();

        if (cpus < 0) {
                p_err("Can't get # of possible cpus: %s", strerror(-cpus));
                exit(-1);
        }
        return cpus;
}

static char *
ifindex_to_name_ns(__u32 ifindex, __u32 ns_dev, __u32 ns_ino, char *buf)
{
        struct stat st;
        int err;

        err = stat("/proc/self/ns/net", &st);
        if (err) {
                p_err("Can't stat /proc/self: %s", strerror(errno));
                return NULL;
        }

        if (st.st_dev != ns_dev || st.st_ino != ns_ino)
                return NULL;

        return if_indextoname(ifindex, buf);
}

static int read_sysfs_hex_int(char *path)
{
        char vendor_id_buf[8];
        int len;
        int fd;

        fd = open(path, O_RDONLY);
        if (fd < 0) {
                p_err("Can't open %s: %s", path, strerror(errno));
                return -1;
        }

        len = read(fd, vendor_id_buf, sizeof(vendor_id_buf));
        close(fd);
        if (len < 0) {
                p_err("Can't read %s: %s", path, strerror(errno));
                return -1;
        }
        if (len >= (int)sizeof(vendor_id_buf)) {
                p_err("Value in %s too long", path);
                return -1;
        }

        vendor_id_buf[len] = 0;

        return strtol(vendor_id_buf, NULL, 0);
}

static int read_sysfs_netdev_hex_int(char *devname, const char *entry_name)
{
        char full_path[64];

        snprintf(full_path, sizeof(full_path), "/sys/class/net/%s/device/%s",
                 devname, entry_name);

        return read_sysfs_hex_int(full_path);
}

const char *
ifindex_to_arch(__u32 ifindex, __u64 ns_dev, __u64 ns_ino, const char **opt)
{
        __maybe_unused int device_id;
        char devname[IF_NAMESIZE];
        int vendor_id;

        if (!ifindex_to_name_ns(ifindex, ns_dev, ns_ino, devname)) {
                p_err("Can't get net device name for ifindex %u: %s", ifindex,
                      strerror(errno));
                return NULL;
        }

        vendor_id = read_sysfs_netdev_hex_int(devname, "vendor");
        if (vendor_id < 0) {
                p_err("Can't get device vendor id for %s", devname);
                return NULL;
        }

        switch (vendor_id) {
#ifdef HAVE_LIBBFD_SUPPORT
        case 0x19ee:
                device_id = read_sysfs_netdev_hex_int(devname, "device");
                if (device_id != 0x4000 &&
                    device_id != 0x6000 &&
                    device_id != 0x6003)
                        p_info("Unknown NFP device ID, assuming it is NFP-6xxx arch");
                *opt = "ctx4";
                return "NFP-6xxx";
#endif /* HAVE_LIBBFD_SUPPORT */
        /* No NFP support in LLVM, we have no valid triple to return. */
        default:
                p_err("Can't get arch name for device vendor id 0x%04x",
                      (unsigned int)vendor_id);
                return NULL;
        }
}

void print_dev_plain(__u32 ifindex, __u64 ns_dev, __u64 ns_inode)
{
        char name[IF_NAMESIZE];

        if (!ifindex)
                return;

        printf("  offloaded_to ");
        if (ifindex_to_name_ns(ifindex, ns_dev, ns_inode, name))
                printf("%s", name);
        else
                printf("ifindex %u ns_dev %llu ns_ino %llu",
                       ifindex, ns_dev, ns_inode);
}

void print_dev_json(__u32 ifindex, __u64 ns_dev, __u64 ns_inode)
{
        char name[IF_NAMESIZE];

        if (!ifindex)
                return;

        jsonw_name(json_wtr, "dev");
        jsonw_start_object(json_wtr);
        jsonw_uint_field(json_wtr, "ifindex", ifindex);
        jsonw_uint_field(json_wtr, "ns_dev", ns_dev);
        jsonw_uint_field(json_wtr, "ns_inode", ns_inode);
        if (ifindex_to_name_ns(ifindex, ns_dev, ns_inode, name))
                jsonw_string_field(json_wtr, "ifname", name);
        jsonw_end_object(json_wtr);
}

int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what)
{
        char *endptr;

        NEXT_ARGP();

        if (*val) {
                p_err("%s already specified", what);
                return -1;
        }

        *val = strtoul(**argv, &endptr, 0);
        if (*endptr) {
                p_err("can't parse %s as %s", **argv, what);
                return -1;
        }
        NEXT_ARGP();

        return 0;
}

int __printf(2, 0)
print_all_levels(__maybe_unused enum libbpf_print_level level,
                 const char *format, va_list args)
{
        return vfprintf(stderr, format, args);
}

static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
{
        char prog_name[MAX_PROG_FULL_NAME];
        unsigned int id = 0;
        int fd, nb_fds = 0;
        void *tmp;
        int err;

        while (true) {
                struct bpf_prog_info info = {};
                __u32 len = sizeof(info);

                err = bpf_prog_get_next_id(id, &id);
                if (err) {
                        if (errno != ENOENT) {
                                p_err("%s", strerror(errno));
                                goto err_close_fds;
                        }
                        return nb_fds;
                }

                fd = bpf_prog_get_fd_by_id(id);
                if (fd < 0) {
                        p_err("can't get prog by id (%u): %s",
                              id, strerror(errno));
                        goto err_close_fds;
                }

                err = bpf_prog_get_info_by_fd(fd, &info, &len);
                if (err) {
                        p_err("can't get prog info (%u): %s",
                              id, strerror(errno));
                        goto err_close_fd;
                }

                if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) {
                        close(fd);
                        continue;
                }

                if (!tag) {
                        get_prog_full_name(&info, fd, prog_name,
                                           sizeof(prog_name));
                        if (strncmp(nametag, prog_name, sizeof(prog_name))) {
                                close(fd);
                                continue;
                        }
                }

                if (nb_fds > 0) {
                        tmp = realloc(*fds, (nb_fds + 1) * sizeof(int));
                        if (!tmp) {
                                p_err("failed to realloc");
                                goto err_close_fd;
                        }
                        *fds = tmp;
                }
                (*fds)[nb_fds++] = fd;
        }

err_close_fd:
        close(fd);
err_close_fds:
        while (--nb_fds >= 0)
                close((*fds)[nb_fds]);
        return -1;
}

int prog_parse_fds(int *argc, char ***argv, int **fds)
{
        if (is_prefix(**argv, "id")) {
                unsigned int id;
                char *endptr;

                NEXT_ARGP();

                id = strtoul(**argv, &endptr, 0);
                if (*endptr) {
                        p_err("can't parse %s as ID", **argv);
                        return -1;
                }
                NEXT_ARGP();

                (*fds)[0] = bpf_prog_get_fd_by_id(id);
                if ((*fds)[0] < 0) {
                        p_err("get by id (%u): %s", id, strerror(errno));
                        return -1;
                }
                return 1;
        } else if (is_prefix(**argv, "tag")) {
                unsigned char tag[BPF_TAG_SIZE];

                NEXT_ARGP();

                if (sscanf(**argv, BPF_TAG_FMT, tag, tag + 1, tag + 2,
                           tag + 3, tag + 4, tag + 5, tag + 6, tag + 7)
                    != BPF_TAG_SIZE) {
                        p_err("can't parse tag");
                        return -1;
                }
                NEXT_ARGP();

                return prog_fd_by_nametag(tag, fds, true);
        } else if (is_prefix(**argv, "name")) {
                char *name;

                NEXT_ARGP();

                name = **argv;
                if (strlen(name) > MAX_PROG_FULL_NAME - 1) {
                        p_err("can't parse name");
                        return -1;
                }
                NEXT_ARGP();

                return prog_fd_by_nametag(name, fds, false);
        } else if (is_prefix(**argv, "pinned")) {
                char *path;

                NEXT_ARGP();

                path = **argv;
                NEXT_ARGP();

                (*fds)[0] = open_obj_pinned_any(path, BPF_OBJ_PROG, NULL);
                if ((*fds)[0] < 0)
                        return -1;
                return 1;
        }

        p_err("expected 'id', 'tag', 'name' or 'pinned', got: '%s'?", **argv);
        return -1;
}

int prog_parse_fd(int *argc, char ***argv)
{
        int *fds = NULL;
        int nb_fds, fd;

        fds = malloc(sizeof(int));
        if (!fds) {
                p_err("mem alloc failed");
                return -1;
        }
        nb_fds = prog_parse_fds(argc, argv, &fds);
        if (nb_fds != 1) {
                if (nb_fds > 1) {
                        p_err("several programs match this handle");
                        while (nb_fds--)
                                close(fds[nb_fds]);
                }
                fd = -1;
                goto exit_free;
        }

        fd = fds[0];
exit_free:
        free(fds);
        return fd;
}

static int map_fd_by_name(char *name, int **fds,
                          const struct bpf_get_fd_by_id_opts *opts)
{
        unsigned int id = 0;
        int fd, nb_fds = 0;
        void *tmp;
        int err;

        while (true) {
                LIBBPF_OPTS(bpf_get_fd_by_id_opts, opts_ro);
                struct bpf_map_info info = {};
                __u32 len = sizeof(info);

                err = bpf_map_get_next_id(id, &id);
                if (err) {
                        if (errno != ENOENT) {
                                p_err("%s", strerror(errno));
                                goto err_close_fds;
                        }
                        return nb_fds;
                }

                /* Request a read-only fd to query the map info */
                opts_ro.open_flags = BPF_F_RDONLY;
                fd = bpf_map_get_fd_by_id_opts(id, &opts_ro);
                if (fd < 0) {
                        p_err("can't get map by id (%u): %s",
                              id, strerror(errno));
                        goto err_close_fds;
                }

                err = bpf_map_get_info_by_fd(fd, &info, &len);
                if (err) {
                        p_err("can't get map info (%u): %s",
                              id, strerror(errno));
                        goto err_close_fd;
                }

                if (strncmp(name, info.name, BPF_OBJ_NAME_LEN)) {
                        close(fd);
                        continue;
                }

                /* Get an fd with the requested options, if they differ
                 * from the read-only options used to get the fd above.
                 */
                if (memcmp(opts, &opts_ro, sizeof(opts_ro))) {
                        close(fd);
                        fd = bpf_map_get_fd_by_id_opts(id, opts);
                        if (fd < 0) {
                                p_err("can't get map by id (%u): %s", id,
                                        strerror(errno));
                                goto err_close_fds;
                        }
                }

                if (nb_fds > 0) {
                        tmp = realloc(*fds, (nb_fds + 1) * sizeof(int));
                        if (!tmp) {
                                p_err("failed to realloc");
                                goto err_close_fd;
                        }
                        *fds = tmp;
                }
                (*fds)[nb_fds++] = fd;
        }

err_close_fd:
        close(fd);
err_close_fds:
        while (--nb_fds >= 0)
                close((*fds)[nb_fds]);
        return -1;
}

int map_parse_fds(int *argc, char ***argv, int **fds, __u32 open_flags)
{
        LIBBPF_OPTS(bpf_get_fd_by_id_opts, opts);

        assert((open_flags & ~BPF_F_RDONLY) == 0);
        opts.open_flags = open_flags;

        if (is_prefix(**argv, "id")) {
                unsigned int id;
                char *endptr;

                NEXT_ARGP();

                id = strtoul(**argv, &endptr, 0);
                if (*endptr) {
                        p_err("can't parse %s as ID", **argv);
                        return -1;
                }
                NEXT_ARGP();

                (*fds)[0] = bpf_map_get_fd_by_id_opts(id, &opts);
                if ((*fds)[0] < 0) {
                        p_err("get map by id (%u): %s", id, strerror(errno));
                        return -1;
                }
                return 1;
        } else if (is_prefix(**argv, "name")) {
                char *name;

                NEXT_ARGP();

                name = **argv;
                if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {
                        p_err("can't parse name");
                        return -1;
                }
                NEXT_ARGP();

                return map_fd_by_name(name, fds, &opts);
        } else if (is_prefix(**argv, "pinned")) {
                char *path;
                LIBBPF_OPTS(bpf_obj_get_opts, get_opts);
                get_opts.file_flags = open_flags;

                NEXT_ARGP();

                path = **argv;
                NEXT_ARGP();

                (*fds)[0] = open_obj_pinned_any(path, BPF_OBJ_MAP, &get_opts);
                if ((*fds)[0] < 0)
                        return -1;
                return 1;
        }

        p_err("expected 'id', 'name' or 'pinned', got: '%s'?", **argv);
        return -1;
}

int map_parse_fd(int *argc, char ***argv, __u32 open_flags)
{
        int *fds = NULL;
        int nb_fds, fd;

        fds = malloc(sizeof(int));
        if (!fds) {
                p_err("mem alloc failed");
                return -1;
        }
        nb_fds = map_parse_fds(argc, argv, &fds, open_flags);
        if (nb_fds != 1) {
                if (nb_fds > 1) {
                        p_err("several maps match this handle");
                        while (nb_fds--)
                                close(fds[nb_fds]);
                }
                fd = -1;
                goto exit_free;
        }

        fd = fds[0];
exit_free:
        free(fds);
        return fd;
}

int map_parse_fd_and_info(int *argc, char ***argv, struct bpf_map_info *info,
                          __u32 *info_len, __u32 open_flags)
{
        int err;
        int fd;

        fd = map_parse_fd(argc, argv, open_flags);
        if (fd < 0)
                return -1;

        err = bpf_map_get_info_by_fd(fd, info, info_len);
        if (err) {
                p_err("can't get map info: %s", strerror(errno));
                close(fd);
                return err;
        }

        return fd;
}

size_t hash_fn_for_key_as_id(long key, void *ctx)
{
        return key;
}

bool equal_fn_for_key_as_id(long k1, long k2, void *ctx)
{
        return k1 == k2;
}

const char *bpf_attach_type_input_str(enum bpf_attach_type t)
{
        switch (t) {
        case BPF_CGROUP_INET_INGRESS:           return "ingress";
        case BPF_CGROUP_INET_EGRESS:            return "egress";
        case BPF_CGROUP_INET_SOCK_CREATE:       return "sock_create";
        case BPF_CGROUP_INET_SOCK_RELEASE:      return "sock_release";
        case BPF_CGROUP_SOCK_OPS:               return "sock_ops";
        case BPF_CGROUP_DEVICE:                 return "device";
        case BPF_CGROUP_INET4_BIND:             return "bind4";
        case BPF_CGROUP_INET6_BIND:             return "bind6";
        case BPF_CGROUP_INET4_CONNECT:          return "connect4";
        case BPF_CGROUP_INET6_CONNECT:          return "connect6";
        case BPF_CGROUP_INET4_POST_BIND:        return "post_bind4";
        case BPF_CGROUP_INET6_POST_BIND:        return "post_bind6";
        case BPF_CGROUP_INET4_GETPEERNAME:      return "getpeername4";
        case BPF_CGROUP_INET6_GETPEERNAME:      return "getpeername6";
        case BPF_CGROUP_INET4_GETSOCKNAME:      return "getsockname4";
        case BPF_CGROUP_INET6_GETSOCKNAME:      return "getsockname6";
        case BPF_CGROUP_UDP4_SENDMSG:           return "sendmsg4";
        case BPF_CGROUP_UDP6_SENDMSG:           return "sendmsg6";
        case BPF_CGROUP_SYSCTL:                 return "sysctl";
        case BPF_CGROUP_UDP4_RECVMSG:           return "recvmsg4";
        case BPF_CGROUP_UDP6_RECVMSG:           return "recvmsg6";
        case BPF_CGROUP_GETSOCKOPT:             return "getsockopt";
        case BPF_CGROUP_SETSOCKOPT:             return "setsockopt";
        case BPF_TRACE_RAW_TP:                  return "raw_tp";
        case BPF_TRACE_FENTRY:                  return "fentry";
        case BPF_TRACE_FEXIT:                   return "fexit";
        case BPF_MODIFY_RETURN:                 return "mod_ret";
        case BPF_TRACE_FSESSION:                return "fsession";
        case BPF_SK_REUSEPORT_SELECT:           return "sk_skb_reuseport_select";
        case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE:        return "sk_skb_reuseport_select_or_migrate";
        default:        return libbpf_bpf_attach_type_str(t);
        }
}

int pathname_concat(char *buf, int buf_sz, const char *path,
                    const char *name)
{
        int len;

        len = snprintf(buf, buf_sz, "%s/%s", path, name);
        if (len < 0)
                return -EINVAL;
        if (len >= buf_sz)
                return -ENAMETOOLONG;

        return 0;
}

static bool read_next_kernel_config_option(gzFile file, char *buf, size_t n,
                                           char **value)
{
        char *sep;

        while (gzgets(file, buf, n)) {
                if (strncmp(buf, "CONFIG_", 7))
                        continue;

                sep = strchr(buf, '=');
                if (!sep)
                        continue;

                /* Trim ending '\n' */
                buf[strlen(buf) - 1] = '\0';

                /* Split on '=' and ensure that a value is present. */
                *sep = '\0';
                if (!sep[1])
                        continue;

                *value = sep + 1;
                return true;
        }

        return false;
}

int read_kernel_config(const struct kernel_config_option *requested_options,
                       size_t num_options, char **out_values,
                       const char *define_prefix)
{
        struct utsname utsn;
        char path[PATH_MAX];
        gzFile file = NULL;
        char buf[4096];
        char *value;
        size_t i;
        int ret = 0;

        if (!requested_options || !out_values || num_options == 0)
                return -1;

        if (!uname(&utsn)) {
                snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);

                /* gzopen also accepts uncompressed files. */
                file = gzopen(path, "r");
        }

        if (!file) {
                /* Some distributions build with CONFIG_IKCONFIG=y and put the
                 * config file at /proc/config.gz.
                 */
                file = gzopen("/proc/config.gz", "r");
        }

        if (!file) {
                p_info("skipping kernel config, can't open file: %s",
                        strerror(errno));
                return -1;
        }

        if (!gzgets(file, buf, sizeof(buf)) || !gzgets(file, buf, sizeof(buf))) {
                p_info("skipping kernel config, can't read from file: %s",
                        strerror(errno));
                ret = -1;
                goto end_parse;
        }

        if (strcmp(buf, "# Automatically generated file; DO NOT EDIT.\n")) {
                p_info("skipping kernel config, can't find correct file");
                ret = -1;
                goto end_parse;
        }

        while (read_next_kernel_config_option(file, buf, sizeof(buf), &value)) {
                for (i = 0; i < num_options; i++) {
                        if ((define_prefix && !requested_options[i].macro_dump) ||
                             out_values[i] || strcmp(buf, requested_options[i].name))
                                continue;

                        out_values[i] = strdup(value);
                }
        }

end_parse:
        gzclose(file);
        return ret;
}