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63841bc083
Currently, the kprobe BPF program attachment method for bpf_load is
quite old. The implementation of bpf_load "directly" controls and
manages(create, delete) the kprobe events of DEBUGFS. On the other hand,
using using the libbpf automatically manages the kprobe event.
(under bpf_link interface)
By calling bpf_program__attach(_kprobe) in libbpf, the corresponding
kprobe is created and the BPF program will be attached to this kprobe.
To remove this, by simply invoking bpf_link__destroy will clean up the
event.
This commit refactors kprobe tracing programs (tracex{1~7}_user.c) with
libbpf using bpf_link interface and bpf_program__attach.
tracex2_kern.c, which tracks system calls (sys_*), has been modified to
append prefix depending on architecture.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200516040608.1377876-3-danieltimlee@gmail.com
104 lines
2.2 KiB
C
104 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <unistd.h>
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#include <stdbool.h>
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#include <string.h>
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#include <time.h>
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#include <sys/resource.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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struct pair {
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long long val;
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__u64 ip;
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};
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static __u64 time_get_ns(void)
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{
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struct timespec ts;
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clock_gettime(CLOCK_MONOTONIC, &ts);
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return ts.tv_sec * 1000000000ull + ts.tv_nsec;
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}
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static void print_old_objects(int fd)
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{
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long long val = time_get_ns();
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__u64 key, next_key;
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struct pair v;
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key = write(1, "\e[1;1H\e[2J", 12); /* clear screen */
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key = -1;
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while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
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bpf_map_lookup_elem(fd, &next_key, &v);
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key = next_key;
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if (val - v.val < 1000000000ll)
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/* object was allocated more then 1 sec ago */
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continue;
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printf("obj 0x%llx is %2lldsec old was allocated at ip %llx\n",
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next_key, (val - v.val) / 1000000000ll, v.ip);
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}
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}
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int main(int ac, char **argv)
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{
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struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
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struct bpf_link *links[2];
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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, i, j = 0;
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if (setrlimit(RLIMIT_MEMLOCK, &r)) {
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perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)");
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return 1;
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}
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snprintf(filename, sizeof(filename), "%s_kern.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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/* 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 = bpf_object__find_map_fd_by_name(obj, "my_map");
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if (map_fd < 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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bpf_object__for_each_program(prog, obj) {
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links[j] = bpf_program__attach(prog);
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if (libbpf_get_error(links[j])) {
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fprintf(stderr, "ERROR: bpf_program__attach failed\n");
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links[j] = NULL;
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goto cleanup;
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}
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j++;
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}
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for (i = 0; ; i++) {
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print_old_objects(map_fd);
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sleep(1);
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}
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cleanup:
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for (j--; j >= 0; j--)
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bpf_link__destroy(links[j]);
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bpf_object__close(obj);
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return 0;
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}
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