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a678be5cc7
The bpf sample program syscall_tp is modified to show attachment of more than bpf programs for a particular kernel tracepoint. Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
111 lines
2.6 KiB
C
111 lines
2.6 KiB
C
/* Copyright (c) 2017 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <linux/bpf.h>
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#include <string.h>
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#include <linux/perf_event.h>
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#include <errno.h>
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#include <assert.h>
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#include <stdbool.h>
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#include <sys/resource.h>
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#include "libbpf.h"
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#include "bpf_load.h"
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/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
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* This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
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*/
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static void usage(const char *cmd)
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{
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printf("USAGE: %s [-i num_progs] [-h]\n", cmd);
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printf(" -i num_progs # number of progs of the test\n");
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printf(" -h # help\n");
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}
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static void verify_map(int map_id)
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{
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__u32 key = 0;
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__u32 val;
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if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
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fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
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return;
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}
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if (val == 0) {
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fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
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return;
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}
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val = 0;
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if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
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fprintf(stderr, "map_update failed: %s\n", strerror(errno));
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return;
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}
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}
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static int test(char *filename, int num_progs)
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{
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int i, fd, map0_fds[num_progs], map1_fds[num_progs];
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for (i = 0; i < num_progs; i++) {
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if (load_bpf_file(filename)) {
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fprintf(stderr, "%s", bpf_log_buf);
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return 1;
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}
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printf("prog #%d: map ids %d %d\n", i, map_fd[0], map_fd[1]);
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map0_fds[i] = map_fd[0];
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map1_fds[i] = map_fd[1];
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}
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/* current load_bpf_file has perf_event_open default pid = -1
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* and cpu = 0, which permits attached bpf execution on
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* all cpus for all pid's. bpf program execution ignores
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* cpu affinity.
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*/
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/* trigger some "open" operations */
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fd = open(filename, O_RDONLY);
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if (fd < 0) {
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fprintf(stderr, "open failed: %s\n", strerror(errno));
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return 1;
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}
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close(fd);
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/* verify the map */
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for (i = 0; i < num_progs; i++) {
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verify_map(map0_fds[i]);
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verify_map(map1_fds[i]);
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}
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return 0;
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}
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int main(int argc, char **argv)
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{
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struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
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int opt, num_progs = 1;
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char filename[256];
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while ((opt = getopt(argc, argv, "i:h")) != -1) {
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switch (opt) {
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case 'i':
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num_progs = atoi(optarg);
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break;
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case 'h':
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default:
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usage(argv[0]);
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return 0;
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}
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}
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setrlimit(RLIMIT_MEMLOCK, &r);
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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return test(filename, num_progs);
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}
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