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d4fffba4d0
Currently old compile rule (CLANG-bpf) doesn't contains VMLINUX_H define
flag which is essential for the bpf program that includes "vmlinux.h".
Also old compile rule doesn't directly specify the compile target as bpf,
instead it uses bunch of extra options with clang followed by long chain
of commands. (e.g. clang | opt | llvm-dis | llc)
In Makefile, there is already new compile rule which is more simple and
neat. And it also has -D__VMLINUX_H__ option. By just changing the _kern
suffix to .bpf will inherit the benefit of the new CLANG-BPF compile
target.
Also, this commit adds dummy gnu/stub.h to the samples/bpf directory.
As commit 1c2dd16add ("selftests/bpf: get rid of -D__x86_64__") noted,
compiling with 'clang -target bpf' will raise an error with stubs.h
unless workaround (-D__x86_64) is used. This commit solves this problem
by adding dummy stub.h to make /usr/include/features.h to follow the
expected path as the same way selftests/bpf dealt with.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221224071527.2292-4-danieltimlee@gmail.com
115 lines
2.4 KiB
C
115 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <unistd.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include "cgroup_helpers.h"
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#define CGROUP_PATH "/my-cgroup"
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int main(int argc, char **argv)
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{
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pid_t remote_pid, local_pid = getpid();
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int cg2 = -1, idx = 0, rc = 1;
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struct bpf_link *link = NULL;
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struct bpf_program *prog;
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struct bpf_object *obj;
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char filename[256];
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int map_fd[2];
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snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);
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obj = bpf_object__open_file(filename, NULL);
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if (libbpf_get_error(obj)) {
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fprintf(stderr, "ERROR: opening BPF object file failed\n");
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return 0;
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}
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prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
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if (!prog) {
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printf("finding a prog in obj file failed\n");
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goto cleanup;
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}
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/* load BPF program */
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if (bpf_object__load(obj)) {
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fprintf(stderr, "ERROR: loading BPF object file failed\n");
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goto cleanup;
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}
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map_fd[0] = bpf_object__find_map_fd_by_name(obj, "cgroup_map");
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map_fd[1] = bpf_object__find_map_fd_by_name(obj, "perf_map");
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if (map_fd[0] < 0 || map_fd[1] < 0) {
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fprintf(stderr, "ERROR: finding a map in obj file failed\n");
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goto cleanup;
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}
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link = bpf_program__attach(prog);
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if (libbpf_get_error(link)) {
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fprintf(stderr, "ERROR: bpf_program__attach failed\n");
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link = NULL;
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goto cleanup;
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}
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if (setup_cgroup_environment())
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goto err;
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cg2 = create_and_get_cgroup(CGROUP_PATH);
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if (cg2 < 0)
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goto err;
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if (bpf_map_update_elem(map_fd[0], &idx, &cg2, BPF_ANY)) {
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log_err("Adding target cgroup to map");
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goto err;
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}
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if (join_cgroup(CGROUP_PATH))
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goto err;
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/*
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* The installed helper program catched the sync call, and should
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* write it to the map.
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*/
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sync();
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bpf_map_lookup_elem(map_fd[1], &idx, &remote_pid);
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if (local_pid != remote_pid) {
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fprintf(stderr,
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"BPF Helper didn't write correct PID to map, but: %d\n",
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remote_pid);
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goto err;
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}
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/* Verify the negative scenario; leave the cgroup */
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if (join_cgroup("/"))
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goto err;
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remote_pid = 0;
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bpf_map_update_elem(map_fd[1], &idx, &remote_pid, BPF_ANY);
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sync();
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bpf_map_lookup_elem(map_fd[1], &idx, &remote_pid);
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if (local_pid == remote_pid) {
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fprintf(stderr, "BPF cgroup negative test did not work\n");
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goto err;
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}
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rc = 0;
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err:
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if (cg2 != -1)
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close(cg2);
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cleanup_cgroup_environment();
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cleanup:
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bpf_link__destroy(link);
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bpf_object__close(obj);
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return rc;
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}
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