syscall_tp_user.c
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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
*/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <signal.h>
#include <linux/bpf.h>
#include <string.h>
#include <linux/perf_event.h>
#include <errno.h>
#include <assert.h>
#include <stdbool.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
#include "bpf_load.h"
/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
* This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
*/
static void usage(const char *cmd)
{
printf("USAGE: %s [-i num_progs] [-h]\n", cmd);
printf(" -i num_progs # number of progs of the test\n");
printf(" -h # help\n");
}
static void verify_map(int map_id)
{
__u32 key = 0;
__u32 val;
if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
return;
}
if (val == 0) {
fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
return;
}
val = 0;
if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
fprintf(stderr, "map_update failed: %s\n", strerror(errno));
return;
}
}
static int test(char *filename, int num_progs)
{
int i, fd, map0_fds[num_progs], map1_fds[num_progs];
for (i = 0; i < num_progs; i++) {
if (load_bpf_file(filename)) {
fprintf(stderr, "%s", bpf_log_buf);
return 1;
}
printf("prog #%d: map ids %d %d\n", i, map_fd[0], map_fd[1]);
map0_fds[i] = map_fd[0];
map1_fds[i] = map_fd[1];
}
/* current load_bpf_file has perf_event_open default pid = -1
* and cpu = 0, which permits attached bpf execution on
* all cpus for all pid's. bpf program execution ignores
* cpu affinity.
*/
/* trigger some "open" operations */
fd = open(filename, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "open failed: %s\n", strerror(errno));
return 1;
}
close(fd);
/* verify the map */
for (i = 0; i < num_progs; i++) {
verify_map(map0_fds[i]);
verify_map(map1_fds[i]);
}
return 0;
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
int opt, num_progs = 1;
char filename[256];
while ((opt = getopt(argc, argv, "i:h")) != -1) {
switch (opt) {
case 'i':
num_progs = atoi(optarg);
break;
case 'h':
default:
usage(argv[0]);
return 0;
}
}
setrlimit(RLIMIT_MEMLOCK, &r);
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
return test(filename, num_progs);
}