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test-bpf: check if we can mlock() before trying bpf

This commit is contained in:
Lennart Poettering 2019-01-24 10:19:33 +01:00 committed by Zbigniew Jędrzejewski-Szmek
parent 8499b2c26d
commit 3dffcfc78b
1 changed files with 33 additions and 0 deletions
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33
src/test/test-bpf.c
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@ -2,6 +2,7 @@
#include <linux/libbpf.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include "bpf-firewall.h"
@ -14,6 +15,30 @@
#include "tests.h"
#include "unit.h"
/* We use the same limit here that PID 1 bumps RLIMIT_MEMLOCK to if it can */
#define CAN_MEMLOCK_SIZE (64U*1024U*1024U)
static bool can_memlock(void) {
void *p;
bool b;
/* Let's see if we can mlock() a larger blob of memory. BPF programs are charged against
* RLIMIT_MEMLOCK, hence let's first make sure we can lock memory at all, and skip the test if we
* cannot. Why not check RLIMIT_MEMLOCK explicitly? Because in container environments the
* RLIMIT_MEMLOCK value we see might not match the RLIMIT_MEMLOCK value actually in effect. */
p = mmap(NULL, CAN_MEMLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_SHARED, -1, 0);
if (p == MAP_FAILED)
return false;
b = mlock(p, CAN_MEMLOCK_SIZE) >= 0;
if (b)
assert_se(munlock(p, CAN_MEMLOCK_SIZE) >= 0);
assert_se(munmap(p, CAN_MEMLOCK_SIZE) >= 0);
return b;
}
int main(int argc, char *argv[]) {
struct bpf_insn exit_insn[] = {
BPF_MOV64_IMM(BPF_REG_0, 1),
@ -26,6 +51,7 @@ int main(int argc, char *argv[]) {
_cleanup_(manager_freep) Manager *m = NULL;
Unit *u;
char log_buf[65535];
struct rlimit rl;
int r;
test_setup_logging(LOG_DEBUG);
@ -33,6 +59,13 @@ int main(int argc, char *argv[]) {
if (is_run_on_travis_ci())
return log_tests_skipped("test-bpf fails on Travis CI: https://github.com/systemd/systemd/issues/9666");
assert_se(getrlimit(RLIMIT_MEMLOCK, &rl) >= 0);
rl.rlim_cur = rl.rlim_max = MAX3(rl.rlim_cur, rl.rlim_max, CAN_MEMLOCK_SIZE);
(void) setrlimit(RLIMIT_MEMLOCK, &rl);
if (!can_memlock())
return log_tests_skipped("Can't use mlock(), skipping.");
r = enter_cgroup_subroot();
if (r == -ENOMEDIUM)
return log_tests_skipped("cgroupfs not available");