linux/tools/testing/selftests/bpf/testing_helpers.c
Andrii Nakryiko 56d3e44af8 selftests/bpf: detect testing prog flags support
Various tests specify extra testing prog_flags when loading BPF
programs, like BPF_F_TEST_RND_HI32, and more recently also
BPF_F_TEST_REG_INVARIANTS. While BPF_F_TEST_RND_HI32 is old enough to
not cause much problem on older kernels, BPF_F_TEST_REG_INVARIANTS is
very fresh and unconditionally specifying it causes selftests to fail on
even slightly outdated kernels.

This breaks libbpf CI test against 4.9 and 5.15 kernels, it can break
some local development (done outside of VM), etc.

To prevent this, and guard against similar problems in the future, do
runtime detection of supported "testing flags", and only provide those
that host kernel recognizes.

Acked-by: Song Liu <song@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240109231738.575844-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-23 14:40:22 -08:00

460 lines
9.5 KiB
C

// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (C) 2019 Netronome Systems, Inc. */
/* Copyright (C) 2020 Facebook, Inc. */
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "test_progs.h"
#include "testing_helpers.h"
#include <linux/membarrier.h>
int parse_num_list(const char *s, bool **num_set, int *num_set_len)
{
int i, set_len = 0, new_len, num, start = 0, end = -1;
bool *set = NULL, *tmp, parsing_end = false;
char *next;
while (s[0]) {
errno = 0;
num = strtol(s, &next, 10);
if (errno)
return -errno;
if (parsing_end)
end = num;
else
start = num;
if (!parsing_end && *next == '-') {
s = next + 1;
parsing_end = true;
continue;
} else if (*next == ',') {
parsing_end = false;
s = next + 1;
end = num;
} else if (*next == '\0') {
parsing_end = false;
s = next;
end = num;
} else {
return -EINVAL;
}
if (start > end)
return -EINVAL;
if (end + 1 > set_len) {
new_len = end + 1;
tmp = realloc(set, new_len);
if (!tmp) {
free(set);
return -ENOMEM;
}
for (i = set_len; i < start; i++)
tmp[i] = false;
set = tmp;
set_len = new_len;
}
for (i = start; i <= end; i++)
set[i] = true;
}
if (!set || parsing_end)
return -EINVAL;
*num_set = set;
*num_set_len = set_len;
return 0;
}
static int do_insert_test(struct test_filter_set *set,
char *test_str,
char *subtest_str)
{
struct test_filter *tmp, *test;
char **ctmp;
int i;
for (i = 0; i < set->cnt; i++) {
test = &set->tests[i];
if (strcmp(test_str, test->name) == 0) {
free(test_str);
goto subtest;
}
}
tmp = realloc(set->tests, sizeof(*test) * (set->cnt + 1));
if (!tmp)
return -ENOMEM;
set->tests = tmp;
test = &set->tests[set->cnt];
test->name = test_str;
test->subtests = NULL;
test->subtest_cnt = 0;
set->cnt++;
subtest:
if (!subtest_str)
return 0;
for (i = 0; i < test->subtest_cnt; i++) {
if (strcmp(subtest_str, test->subtests[i]) == 0) {
free(subtest_str);
return 0;
}
}
ctmp = realloc(test->subtests,
sizeof(*test->subtests) * (test->subtest_cnt + 1));
if (!ctmp)
return -ENOMEM;
test->subtests = ctmp;
test->subtests[test->subtest_cnt] = subtest_str;
test->subtest_cnt++;
return 0;
}
static int insert_test(struct test_filter_set *set,
char *test_spec,
bool is_glob_pattern)
{
char *pattern, *subtest_str, *ext_test_str, *ext_subtest_str = NULL;
int glob_chars = 0;
if (is_glob_pattern) {
pattern = "%s";
} else {
pattern = "*%s*";
glob_chars = 2;
}
subtest_str = strchr(test_spec, '/');
if (subtest_str) {
*subtest_str = '\0';
subtest_str += 1;
}
ext_test_str = malloc(strlen(test_spec) + glob_chars + 1);
if (!ext_test_str)
goto err;
sprintf(ext_test_str, pattern, test_spec);
if (subtest_str) {
ext_subtest_str = malloc(strlen(subtest_str) + glob_chars + 1);
if (!ext_subtest_str)
goto err;
sprintf(ext_subtest_str, pattern, subtest_str);
}
return do_insert_test(set, ext_test_str, ext_subtest_str);
err:
free(ext_test_str);
free(ext_subtest_str);
return -ENOMEM;
}
int parse_test_list_file(const char *path,
struct test_filter_set *set,
bool is_glob_pattern)
{
char *buf = NULL, *capture_start, *capture_end, *scan_end;
size_t buflen = 0;
int err = 0;
FILE *f;
f = fopen(path, "r");
if (!f) {
err = -errno;
fprintf(stderr, "Failed to open '%s': %d\n", path, err);
return err;
}
while (getline(&buf, &buflen, f) != -1) {
capture_start = buf;
while (isspace(*capture_start))
++capture_start;
capture_end = capture_start;
scan_end = capture_start;
while (*scan_end && *scan_end != '#') {
if (!isspace(*scan_end))
capture_end = scan_end;
++scan_end;
}
if (capture_end == capture_start)
continue;
*(++capture_end) = '\0';
err = insert_test(set, capture_start, is_glob_pattern);
if (err)
break;
}
fclose(f);
return err;
}
int parse_test_list(const char *s,
struct test_filter_set *set,
bool is_glob_pattern)
{
char *input, *state = NULL, *test_spec;
int err = 0;
input = strdup(s);
if (!input)
return -ENOMEM;
while ((test_spec = strtok_r(state ? NULL : input, ",", &state))) {
err = insert_test(set, test_spec, is_glob_pattern);
if (err)
break;
}
free(input);
return err;
}
__u32 link_info_prog_id(const struct bpf_link *link, struct bpf_link_info *info)
{
__u32 info_len = sizeof(*info);
int err;
memset(info, 0, sizeof(*info));
err = bpf_link_get_info_by_fd(bpf_link__fd(link), info, &info_len);
if (err) {
printf("failed to get link info: %d\n", -errno);
return 0;
}
return info->prog_id;
}
int extra_prog_load_log_flags = 0;
int testing_prog_flags(void)
{
static int cached_flags = -1;
static int prog_flags[] = { BPF_F_TEST_RND_HI32, BPF_F_TEST_REG_INVARIANTS };
static struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int insn_cnt = ARRAY_SIZE(insns), i, fd, flags = 0;
LIBBPF_OPTS(bpf_prog_load_opts, opts);
if (cached_flags >= 0)
return cached_flags;
for (i = 0; i < ARRAY_SIZE(prog_flags); i++) {
opts.prog_flags = prog_flags[i];
fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "flag-test", "GPL",
insns, insn_cnt, &opts);
if (fd >= 0) {
flags |= prog_flags[i];
close(fd);
}
}
cached_flags = flags;
return cached_flags;
}
int bpf_prog_test_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd)
{
LIBBPF_OPTS(bpf_object_open_opts, opts,
.kernel_log_level = extra_prog_load_log_flags,
);
struct bpf_object *obj;
struct bpf_program *prog;
__u32 flags;
int err;
obj = bpf_object__open_file(file, &opts);
if (!obj)
return -errno;
prog = bpf_object__next_program(obj, NULL);
if (!prog) {
err = -ENOENT;
goto err_out;
}
if (type != BPF_PROG_TYPE_UNSPEC && bpf_program__type(prog) != type)
bpf_program__set_type(prog, type);
flags = bpf_program__flags(prog) | testing_prog_flags();
bpf_program__set_flags(prog, flags);
err = bpf_object__load(obj);
if (err)
goto err_out;
*pobj = obj;
*prog_fd = bpf_program__fd(prog);
return 0;
err_out:
bpf_object__close(obj);
return err;
}
int bpf_test_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
size_t insns_cnt, const char *license,
__u32 kern_version, char *log_buf,
size_t log_buf_sz)
{
LIBBPF_OPTS(bpf_prog_load_opts, opts,
.kern_version = kern_version,
.prog_flags = testing_prog_flags(),
.log_level = extra_prog_load_log_flags,
.log_buf = log_buf,
.log_size = log_buf_sz,
);
return bpf_prog_load(type, NULL, license, insns, insns_cnt, &opts);
}
__u64 read_perf_max_sample_freq(void)
{
__u64 sample_freq = 5000; /* fallback to 5000 on error */
FILE *f;
f = fopen("/proc/sys/kernel/perf_event_max_sample_rate", "r");
if (f == NULL) {
printf("Failed to open /proc/sys/kernel/perf_event_max_sample_rate: err %d\n"
"return default value: 5000\n", -errno);
return sample_freq;
}
if (fscanf(f, "%llu", &sample_freq) != 1) {
printf("Failed to parse /proc/sys/kernel/perf_event_max_sample_rate: err %d\n"
"return default value: 5000\n", -errno);
}
fclose(f);
return sample_freq;
}
static int finit_module(int fd, const char *param_values, int flags)
{
return syscall(__NR_finit_module, fd, param_values, flags);
}
static int delete_module(const char *name, int flags)
{
return syscall(__NR_delete_module, name, flags);
}
int unload_bpf_testmod(bool verbose)
{
if (kern_sync_rcu())
fprintf(stdout, "Failed to trigger kernel-side RCU sync!\n");
if (delete_module("bpf_testmod", 0)) {
if (errno == ENOENT) {
if (verbose)
fprintf(stdout, "bpf_testmod.ko is already unloaded.\n");
return -1;
}
fprintf(stdout, "Failed to unload bpf_testmod.ko from kernel: %d\n", -errno);
return -1;
}
if (verbose)
fprintf(stdout, "Successfully unloaded bpf_testmod.ko.\n");
return 0;
}
int load_bpf_testmod(bool verbose)
{
int fd;
if (verbose)
fprintf(stdout, "Loading bpf_testmod.ko...\n");
fd = open("bpf_testmod.ko", O_RDONLY);
if (fd < 0) {
fprintf(stdout, "Can't find bpf_testmod.ko kernel module: %d\n", -errno);
return -ENOENT;
}
if (finit_module(fd, "", 0)) {
fprintf(stdout, "Failed to load bpf_testmod.ko into the kernel: %d\n", -errno);
close(fd);
return -EINVAL;
}
close(fd);
if (verbose)
fprintf(stdout, "Successfully loaded bpf_testmod.ko.\n");
return 0;
}
/*
* Trigger synchronize_rcu() in kernel.
*/
int kern_sync_rcu(void)
{
return syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0, 0);
}
int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt)
{
__u32 buf_element_size = sizeof(struct bpf_insn);
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
__u32 xlated_prog_len;
if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
perror("bpf_prog_get_info_by_fd failed");
return -1;
}
xlated_prog_len = info.xlated_prog_len;
if (xlated_prog_len % buf_element_size) {
printf("Program length %u is not multiple of %u\n",
xlated_prog_len, buf_element_size);
return -1;
}
*cnt = xlated_prog_len / buf_element_size;
*buf = calloc(*cnt, buf_element_size);
if (!buf) {
perror("can't allocate xlated program buffer");
return -ENOMEM;
}
bzero(&info, sizeof(info));
info.xlated_prog_len = xlated_prog_len;
info.xlated_prog_insns = (__u64)(unsigned long)*buf;
if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
perror("second bpf_prog_get_info_by_fd failed");
goto out_free_buf;
}
return 0;
out_free_buf:
free(*buf);
*buf = NULL;
return -1;
}