156 lines
3.3 KiB
C
156 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2022 Benjamin Tissoires
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*
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* This is a pure HID-BPF example, and should be considered as such:
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* on the Etekcity Scroll 6E, the X and Y axes will be swapped and
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* inverted. On any other device... Not sure what this will do.
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*
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* This C main file is generic though. To adapt the code and test, users
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* must amend only the .bpf.c file, which this program will load any
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* eBPF program it finds.
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*/
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <libgen.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/resource.h>
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#include <unistd.h>
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#include <linux/bpf.h>
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#include <linux/errno.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include "hid_mouse.skel.h"
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#include "hid_bpf_attach.h"
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static bool running = true;
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static void int_exit(int sig)
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{
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running = false;
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exit(0);
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}
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static void usage(const char *prog)
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{
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fprintf(stderr,
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"%s: %s /sys/bus/hid/devices/0BUS:0VID:0PID:00ID\n\n",
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__func__, prog);
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fprintf(stderr,
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"This program will upload and attach a HID-BPF program to the given device.\n"
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"On the Etekcity Scroll 6E, the X and Y axis will be inverted, but on any other\n"
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"device, chances are high that the device will not be working anymore\n\n"
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"consider this as a demo and adapt the eBPF program to your needs\n"
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"Hit Ctrl-C to unbind the program and reset the device\n");
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}
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static int get_hid_id(const char *path)
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{
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const char *str_id, *dir;
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char uevent[1024];
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int fd;
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memset(uevent, 0, sizeof(uevent));
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snprintf(uevent, sizeof(uevent) - 1, "%s/uevent", path);
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fd = open(uevent, O_RDONLY | O_NONBLOCK);
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if (fd < 0)
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return -ENOENT;
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close(fd);
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dir = basename((char *)path);
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str_id = dir + sizeof("0003:0001:0A37.");
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return (int)strtol(str_id, NULL, 16);
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}
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int main(int argc, char **argv)
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{
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struct hid_mouse *skel;
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struct bpf_program *prog;
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int err;
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const char *optstr = "";
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const char *sysfs_path;
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int opt, hid_id, attach_fd;
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struct attach_prog_args args = {
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.retval = -1,
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};
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DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,
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.ctx_in = &args,
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.ctx_size_in = sizeof(args),
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);
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while ((opt = getopt(argc, argv, optstr)) != -1) {
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switch (opt) {
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default:
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usage(basename(argv[0]));
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return 1;
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}
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}
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if (optind == argc) {
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usage(basename(argv[0]));
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return 1;
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}
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sysfs_path = argv[optind];
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if (!sysfs_path) {
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perror("sysfs");
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return 1;
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}
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skel = hid_mouse__open_and_load();
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if (!skel) {
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fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__);
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return -1;
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}
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hid_id = get_hid_id(sysfs_path);
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if (hid_id < 0) {
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fprintf(stderr, "can not open HID device: %m\n");
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return 1;
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}
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args.hid = hid_id;
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attach_fd = bpf_program__fd(skel->progs.attach_prog);
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if (attach_fd < 0) {
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fprintf(stderr, "can't locate attach prog: %m\n");
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return 1;
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}
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bpf_object__for_each_program(prog, *skel->skeleton->obj) {
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/* ignore syscalls */
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if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING)
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continue;
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args.retval = -1;
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args.prog_fd = bpf_program__fd(prog);
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err = bpf_prog_test_run_opts(attach_fd, &tattr);
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if (err) {
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fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n",
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hid_id, err);
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return 1;
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}
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}
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signal(SIGINT, int_exit);
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signal(SIGTERM, int_exit);
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while (running)
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sleep(1);
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hid_mouse__destroy(skel);
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return 0;
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}
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