linux/samples/bpf/spintest_user.c
Daniel T. Lee e67b2c7154 samples, selftests/bpf: add NULL check for ksym_search
Since, ksym_search added with verification logic for symbols existence,
it could return NULL when the kernel symbols are not loaded.

This commit will add NULL check logic after ksym_search.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-04 16:43:47 +02:00

58 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <unistd.h>
#include <linux/bpf.h>
#include <string.h>
#include <assert.h>
#include <sys/resource.h>
#include "libbpf.h"
#include "bpf_load.h"
#include "trace_helpers.h"
int main(int ac, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
long key, next_key, value;
char filename[256];
struct ksym *sym;
int i;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
setrlimit(RLIMIT_MEMLOCK, &r);
if (load_kallsyms()) {
printf("failed to process /proc/kallsyms\n");
return 2;
}
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 1;
}
for (i = 0; i < 5; i++) {
key = 0;
printf("kprobing funcs:");
while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
bpf_map_lookup_elem(map_fd[0], &next_key, &value);
assert(next_key == value);
sym = ksym_search(value);
key = next_key;
if (!sym) {
printf("ksym not found. Is kallsyms loaded?\n");
continue;
}
printf(" %s", sym->name);
}
if (key)
printf("\n");
key = 0;
while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0)
bpf_map_delete_elem(map_fd[0], &next_key);
sleep(1);
}
return 0;
}