selftests/bpf: Fix arg parsing in veristat, test_progs

Current code parses arguments with strtok_r() using a construct like

    char *state = NULL;
    while ((next = strtok_r(state ? NULL : input, ",", &state))) {
        ...
    }

where logic assumes the 'state' var can distinguish between first and
subsequent strtok_r() calls, and adjusts parameters accordingly. However,
'state' is strictly internal context for strtok_r() and no such assumptions
are supported in the man page. Moreover, the exact behaviour of 'state'
depends on the libc implementation, making the above code fragile.

Indeed, invoking "./test_progs -t <test_name>" on mips64el/musl will hang,
with the above code in an infinite loop.

Similarly, we see strange behaviour running 'veristat' on mips64el/musl:

    $ ./veristat -e file,prog,verdict,insns -C two-ok add-failure
    Can't specify more than 9 stats

Rewrite code using a counter to distinguish between strtok_r() calls.

Fixes: 61ddff373ffa ("selftests/bpf: Improve by-name subtest selection logic in prog_tests")
Fixes: 394169b079b5 ("selftests/bpf: add comparison mode to veristat")
Fixes: c8bc5e050976 ("selftests/bpf: Add veristat tool for mass-verifying BPF object files")
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/392d8bf5559f85fa37926c1494e62312ef252c3d.1722244708.git.tony.ambardar@gmail.com

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index ac7c66f4fc7b..c217e12bd9da 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -221,13 +221,13 @@ int parse_test_list(const char *s,
 		    bool is_glob_pattern)
 {
 	char *input, *state = NULL, *test_spec;
-	int err = 0;
+	int err = 0, cnt = 0;
 
 	input = strdup(s);
 	if (!input)
 		return -ENOMEM;
 
-	while ((test_spec = strtok_r(state ? NULL : input, ",", &state))) {
+	while ((test_spec = strtok_r(cnt++ ? NULL : input, ",", &state))) {
 		err = insert_test(set, test_spec, is_glob_pattern);
 		if (err)
 			break;