1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * tools/testing/selftests/kvm/lib/assert.c
4 *
5 * Copyright (C) 2018, Google LLC.
6 */
7
8#define _GNU_SOURCE /* for getline(3) and strchrnul(3)*/
9
10#include "test_util.h"
11
12#include <execinfo.h>
13#include <sys/syscall.h>
14
15#include "kselftest.h"
16
17/* Dumps the current stack trace to stderr. */
18static void __attribute__((noinline)) test_dump_stack(void);
19static void test_dump_stack(void)
20{
21	/*
22	 * Build and run this command:
23	 *
24	 *	addr2line -s -e /proc/$PPID/exe -fpai {backtrace addresses} | \
25	 *		grep -v test_dump_stack | cat -n 1>&2
26	 *
27	 * Note that the spacing is different and there's no newline.
28	 */
29	size_t i;
30	size_t n = 20;
31	void *stack[n];
32	const char *addr2line = "addr2line -s -e /proc/$PPID/exe -fpai";
33	const char *pipeline = "|cat -n 1>&2";
34	char cmd[strlen(addr2line) + strlen(pipeline) +
35		 /* N bytes per addr * 2 digits per byte + 1 space per addr: */
36		 n * (((sizeof(void *)) * 2) + 1) +
37		 /* Null terminator: */
38		 1];
39	char *c;
40
41	n = backtrace(stack, n);
42	c = &cmd[0];
43	c += sprintf(c, "%s", addr2line);
44	/*
45	 * Skip the first 3 frames: backtrace, test_dump_stack, and
46	 * test_assert. We hope that backtrace isn't inlined and the other two
47	 * we've declared noinline.
48	 */
49	for (i = 2; i < n; i++)
50		c += sprintf(c, " %lx", ((unsigned long) stack[i]) - 1);
51	c += sprintf(c, "%s", pipeline);
52#pragma GCC diagnostic push
53#pragma GCC diagnostic ignored "-Wunused-result"
54	system(cmd);
55#pragma GCC diagnostic pop
56}
57
58static pid_t _gettid(void)
59{
60	return syscall(SYS_gettid);
61}
62
63void __attribute__((noinline))
64test_assert(bool exp, const char *exp_str,
65	const char *file, unsigned int line, const char *fmt, ...)
66{
67	va_list ap;
68
69	if (!(exp)) {
70		va_start(ap, fmt);
71
72		fprintf(stderr, "==== Test Assertion Failure ====\n"
73			"  %s:%u: %s\n"
74			"  pid=%d tid=%d - %s\n",
75			file, line, exp_str, getpid(), _gettid(),
76			strerror(errno));
77		test_dump_stack();
78		if (fmt) {
79			fputs("  ", stderr);
80			vfprintf(stderr, fmt, ap);
81			fputs("\n", stderr);
82		}
83		va_end(ap);
84
85		if (errno == EACCES) {
86			print_skip("Access denied - Exiting");
87			exit(KSFT_SKIP);
88		}
89		exit(254);
90	}
91
92	return;
93}
94