On 08/02, Andrii Nakryiko wrote:
> On 8/2/19 10:17 AM, Stanislav Fomichev wrote:
> > Use open_memstream to override stdout during test execution.
> > The copy of the original stdout is held in env.stdout and used
> > to print subtest info and dump failed log.
>
> I really like the idea. I didn't know about open_memstream, it's awesome.
> Thanks!
One possible downside of using open_memstream is that it's glibc
specific. I probably need to wrap it in #ifdef __GLIBC__ to make
it work with other libcs and just print everything as it was before :-(.
I'm not sure we care though.
> > test_{v,}printf are now simple wrappers around stdout and will be
> > removed in the next patch.
> >
> > Cc: Andrii Nakryiko <andr...@fb.com>
> > Signed-off-by: Stanislav Fomichev <s...@google.com>
> > ---
> > tools/testing/selftests/bpf/test_progs.c | 100 ++++++++++-------------
> > tools/testing/selftests/bpf/test_progs.h | 2 +-
> > 2 files changed, 46 insertions(+), 56 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/test_progs.c
> > b/tools/testing/selftests/bpf/test_progs.c
> > index db00196c8315..00d1565d01a3 100644
> > --- a/tools/testing/selftests/bpf/test_progs.c
> > +++ b/tools/testing/selftests/bpf/test_progs.c
> > @@ -40,14 +40,22 @@ static bool should_run(struct test_selector *sel, int
> > num, const char *name)
> >
> > static void dump_test_log(const struct prog_test_def *test, bool failed)
> > {
> > - if (env.verbose || test->force_log || failed) {
> > - if (env.log_cnt) {
> > - fprintf(stdout, "%s", env.log_buf);
> > - if (env.log_buf[env.log_cnt - 1] != '\n')
> > - fprintf(stdout, "\n");
> > + if (stdout == env.stdout)
> > + return;
> > +
> > + fflush(stdout); /* exports env.log_buf & env.log_cap */
> > +
> > + if (env.log_cap && (env.verbose || test->force_log || failed)) {
> > + int len = strlen(env.log_buf);
>
> env.log_cap is not really a capacity, it's actual number of bytes (without
> terminating zero), so there is no need to do strlen and it's probably better
> to rename env.log_cap into env.log_cnt.
I'll rename it to log_size to match open_memstream args.
We probably still need to do strlen because open_memstream can allocate
bigger buffer to hold the data.
> > +
> > + if (len) {
> > + fprintf(env.stdout, "%s", env.log_buf);
> > + if (env.log_buf[len - 1] != '\n')
> > + fprintf(env.stdout, "\n");
> > +
> > + fseeko(stdout, 0, SEEK_SET);
> Same bug as I already fixed with env.log_cnt = 0 being inside this if. You
> want to do seek always, not just when you print output log.
SG, will move to where we currently clear log_cnt, thanks!
> > /* rewind */
> > }
> > }
> > - env.log_cnt = 0;
> > }
> >
> > void test__end_subtest()
> > @@ -62,7 +70,7 @@ void test__end_subtest()
> >
> > dump_test_log(test, sub_error_cnt);
> >
> > - printf("#%d/%d %s:%s\n",
> > + fprintf(env.stdout, "#%d/%d %s:%s\n",
> > test->test_num, test->subtest_num,
> > test->subtest_name, sub_error_cnt ? "FAIL" : "OK");
> > }
> > @@ -100,53 +108,7 @@ void test__force_log() {
> >
> > void test__vprintf(const char *fmt, va_list args)
> > {
> > - size_t rem_sz;
> > - int ret = 0;
> > -
> > - if (env.verbose || (env.test && env.test->force_log)) {
> > - vfprintf(stderr, fmt, args);
> > - return;
> > - }
> > -
> > -try_again:
> > - rem_sz = env.log_cap - env.log_cnt;
> > - if (rem_sz) {
> > - va_list ap;
> > -
> > - va_copy(ap, args);
> > - /* we reserved extra byte for \0 at the end */
> > - ret = vsnprintf(env.log_buf + env.log_cnt, rem_sz + 1, fmt, ap);
> > - va_end(ap);
> > -
> > - if (ret < 0) {
> > - env.log_buf[env.log_cnt] = '\0';
> > - fprintf(stderr, "failed to log w/ fmt '%s'\n", fmt);
> > - return;
> > - }
> > - }
> > -
> > - if (!rem_sz || ret > rem_sz) {
> > - size_t new_sz = env.log_cap * 3 / 2;
> > - char *new_buf;
> > -
> > - if (new_sz < 4096)
> > - new_sz = 4096;
> > - if (new_sz < ret + env.log_cnt)
> > - new_sz = ret + env.log_cnt;
> > -
> > - /* +1 for guaranteed space for terminating \0 */
> > - new_buf = realloc(env.log_buf, new_sz + 1);
> > - if (!new_buf) {
> > - fprintf(stderr, "failed to realloc log buffer: %d\n",
> > - errno);
> > - return;
> > - }
> > - env.log_buf = new_buf;
> > - env.log_cap = new_sz;
> > - goto try_again;
> > - }
> > -
> > - env.log_cnt += ret;
> > + vprintf(fmt, args);
> > }
> >
> > void test__printf(const char *fmt, ...)
> > @@ -477,6 +439,32 @@ static error_t parse_arg(int key, char *arg, struct
> > argp_state *state)
> > return 0;
> > }
> >
> > +static void stdout_hijack(void)
> > +{
> > + if (env.verbose || (env.test && env.test->force_log)) {
> > + /* nothing to do, output to stdout by default */
> > + return;
> > + }
> > +
> > + /* stdout -> buffer */
> > + fflush(stdout);
> > + stdout = open_memstream(&env.log_buf, &env.log_cap);
> Check errors and restore original stdout if something went wrong? (And emit
> some warning to stderr).
Good point, will do.
> > +}
> > +
> > +static void stdout_restore(void)
> > +{
> > + if (stdout == env.stdout)
> > + return;
> > +
> > + fclose(stdout);
> > + free(env.log_buf);
> > +
> > + env.log_buf = NULL;
> > + env.log_cap = 0;
> > +
> > + stdout = env.stdout;
> > +}
> > +
> > int main(int argc, char **argv)
> > {
> > static const struct argp argp = {
> > @@ -495,6 +483,7 @@ int main(int argc, char **argv)
> > srand(time(NULL));
> >
> > env.jit_enabled = is_jit_enabled();
> > + env.stdout = stdout;
> >
> > for (i = 0; i < prog_test_cnt; i++) {
> > struct prog_test_def *test = &prog_test_defs[i];
> > @@ -508,6 +497,7 @@ int main(int argc, char **argv)
> > test->test_num, test->test_name))
> > continue;
> >
> > + stdout_hijack();
> Why do you do this for every test? Just do once before all the tests and
> restore after?
We can do that, my thinking was to limit the area of hijacking :-)
But that would work as well, less allocations per test, I guess. Will
do.
> > test->run_test();
> > /* ensure last sub-test is finalized properly */
> > if (test->subtest_name)
> > @@ -522,6 +512,7 @@ int main(int argc, char **argv)
> > env.succ_cnt++;
> >
> > dump_test_log(test, test->error_cnt);
> > + stdout_restore();
> >
> > printf("#%d %s:%s\n", test->test_num, test->test_name,
> > test->error_cnt ? "FAIL" : "OK");
> > @@ -529,7 +520,6 @@ int main(int argc, char **argv)
> > printf("Summary: %d/%d PASSED, %d FAILED\n",
> > env.succ_cnt, env.sub_succ_cnt, env.fail_cnt);
> >
> > - free(env.log_buf);
> > free(env.test_selector.num_set);
> > free(env.subtest_selector.num_set);
> >
> > diff --git a/tools/testing/selftests/bpf/test_progs.h
> > b/tools/testing/selftests/bpf/test_progs.h
> > index afd14962456f..9fd89078494f 100644
> > --- a/tools/testing/selftests/bpf/test_progs.h
> > +++ b/tools/testing/selftests/bpf/test_progs.h
> > @@ -56,8 +56,8 @@ struct test_env {
> > bool jit_enabled;
> >
> > struct prog_test_def *test;
> > + FILE *stdout;
> > char *log_buf;
> > - size_t log_cnt;
> > size_t log_cap;
> So it's actually log_cnt that's assigned on fflush for memstream, according
> to man page, so probably keep log_cnt, delete log_cap.
Ack. See above, will rename to log_size, let me know if you disagree.
> > int succ_cnt; /* successful tests */
