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 
11 void 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 
73 cleanup:
74 	trace_printk__destroy(skel);
75 	free(buf);
76 	if (fp)
77 		fclose(fp);
78 }
79