1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2020, Oracle and/or its affiliates. */
 3
 4#include <test_progs.h>
 5
 6#include "trace_printk.lskel.h"
 7
 8#define TRACEBUF	"/sys/kernel/debug/tracing/trace_pipe"
 9#define SEARCHMSG	"testing,testing"
10
11void test_trace_printk(void)
12{
13	int err, iter = 0, duration = 0, found = 0;
14	struct trace_printk__bss *bss;
15	struct trace_printk *skel;
16	char *buf = NULL;
17	FILE *fp = NULL;
18	size_t buflen;
19
20	skel = trace_printk__open();
21	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
22		return;
23
24	ASSERT_EQ(skel->rodata->fmt[0], 'T', "invalid printk fmt string");
25	skel->rodata->fmt[0] = 't';
26
27	err = trace_printk__load(skel);
28	if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
29		goto cleanup;
30
31	bss = skel->bss;
32
33	err = trace_printk__attach(skel);
34	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
35		goto cleanup;
36
37	fp = fopen(TRACEBUF, "r");
38	if (CHECK(fp == NULL, "could not open trace buffer",
39		  "error %d opening %s", errno, TRACEBUF))
40		goto cleanup;
41
42	/* We do not want to wait forever if this test fails... */
43	fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
44
45	/* wait for tracepoint to trigger */
46	usleep(1);
47	trace_printk__detach(skel);
48
49	if (CHECK(bss->trace_printk_ran == 0,
50		  "bpf_trace_printk never ran",
51		  "ran == %d", bss->trace_printk_ran))
52		goto cleanup;
53
54	if (CHECK(bss->trace_printk_ret <= 0,
55		  "bpf_trace_printk returned <= 0 value",
56		  "got %d", bss->trace_printk_ret))
57		goto cleanup;
58
59	/* verify our search string is in the trace buffer */
60	while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
61		if (strstr(buf, SEARCHMSG) != NULL)
62			found++;
63		if (found == bss->trace_printk_ran)
64			break;
65		if (++iter > 1000)
66			break;
67	}
68
69	if (CHECK(!found, "message from bpf_trace_printk not found",
70		  "no instance of %s in %s", SEARCHMSG, TRACEBUF))
71		goto cleanup;
72
73cleanup:
74	trace_printk__destroy(skel);
75	free(buf);
76	if (fp)
77		fclose(fp);
78}