linux/samples/bpf/tracex4_user.c
Kumar Kartikeya Dwivedi 50b796e645 samples: bpf: Fix a couple of warnings
cookie_uid_helper_example.c: In function ‘main’:
cookie_uid_helper_example.c:178:69: warning: ‘ -j ACCEPT’ directive
	writing 10 bytes into a region of size between 8 and 58
	[-Wformat-overflow=]
  178 |  sprintf(rules, "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
      |								       ^~~~~~~~~~
/home/kkd/src/linux/samples/bpf/cookie_uid_helper_example.c:178:9: note:
	‘sprintf’ output between 53 and 103 bytes into a destination of size 100
  178 |  sprintf(rules, "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  179 |         file);
      |         ~~~~~

Fix by using snprintf and a sufficiently sized buffer.

tracex4_user.c:35:15: warning: ‘write’ reading 12 bytes from a region of
	size 11 [-Wstringop-overread]
   35 |         key = write(1, "\e[1;1H\e[2J", 12); /* clear screen */
      |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Use size as 11.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-2-memxor@gmail.com
2021-08-24 14:48:40 -07:00

98 lines
2.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
*/
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <stdbool.h>
#include <string.h>
#include <time.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
struct pair {
long long val;
__u64 ip;
};
static __u64 time_get_ns(void)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return ts.tv_sec * 1000000000ull + ts.tv_nsec;
}
static void print_old_objects(int fd)
{
long long val = time_get_ns();
__u64 key, next_key;
struct pair v;
key = write(1, "\e[1;1H\e[2J", 11); /* clear screen */
key = -1;
while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
bpf_map_lookup_elem(fd, &next_key, &v);
key = next_key;
if (val - v.val < 1000000000ll)
/* object was allocated more then 1 sec ago */
continue;
printf("obj 0x%llx is %2lldsec old was allocated at ip %llx\n",
next_key, (val - v.val) / 1000000000ll, v.ip);
}
}
int main(int ac, char **argv)
{
struct bpf_link *links[2];
struct bpf_program *prog;
struct bpf_object *obj;
char filename[256];
int map_fd, i, j = 0;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return 0;
}
/* load BPF program */
if (bpf_object__load(obj)) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
goto cleanup;
}
map_fd = bpf_object__find_map_fd_by_name(obj, "my_map");
if (map_fd < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
bpf_object__for_each_program(prog, obj) {
links[j] = bpf_program__attach(prog);
if (libbpf_get_error(links[j])) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
links[j] = NULL;
goto cleanup;
}
j++;
}
for (i = 0; ; i++) {
print_old_objects(map_fd);
sleep(1);
}
cleanup:
for (j--; j >= 0; j--)
bpf_link__destroy(links[j]);
bpf_object__close(obj);
return 0;
}