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. */
18 static void __attribute__((noinline)) test_dump_stack(void);
test_dump_stack(void)19 static void test_dump_stack(void)
20 {
21 /*
22 * Build and run this command:
23 *
24 * addr2line -s -e /proc/$PPID/exe -fpai {backtrace addresses} | \
25 * cat -n 1>&2
26 *
27 * Note that the spacing is different and there's no newline.
28 */
29 size_t i;
30 size_t n = 20;
31 void *stack[n];
32 const char *addr2line = "addr2line -s -e /proc/$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 = cmd;
40
41 n = backtrace(stack, n);
42 /*
43 * Skip the first 2 frames, which should be test_dump_stack() and
44 * test_assert(); both of which are declared noinline. Bail if the
45 * resulting stack trace would be empty. Otherwise, addr2line will block
46 * waiting for addresses to be passed in via stdin.
47 */
48 if (n <= 2) {
49 fputs(" (stack trace empty)\n", stderr);
50 return;
51 }
52
53 c += sprintf(c, "%s", addr2line);
54 for (i = 2; i < n; i++)
55 c += sprintf(c, " %lx", ((unsigned long) stack[i]) - 1);
56
57 c += sprintf(c, "%s", pipeline);
58 #pragma GCC diagnostic push
59 #pragma GCC diagnostic ignored "-Wunused-result"
60 system(cmd);
61 #pragma GCC diagnostic pop
62 }
63
_gettid(void)64 static pid_t _gettid(void)
65 {
66 return syscall(SYS_gettid);
67 }
68
69 void __attribute__((noinline))
test_assert(bool exp,const char * exp_str,const char * file,unsigned int line,const char * fmt,...)70 test_assert(bool exp, const char *exp_str,
71 const char *file, unsigned int line, const char *fmt, ...)
72 {
73 va_list ap;
74
75 if (!(exp)) {
76 va_start(ap, fmt);
77
78 fprintf(stderr, "==== Test Assertion Failure ====\n"
79 " %s:%u: %s\n"
80 " pid=%d tid=%d errno=%d - %s\n",
81 file, line, exp_str, getpid(), _gettid(),
82 errno, strerror(errno));
83 test_dump_stack();
84 if (fmt) {
85 fputs(" ", stderr);
86 vfprintf(stderr, fmt, ap);
87 fputs("\n", stderr);
88 }
89 va_end(ap);
90
91 if (errno == EACCES) {
92 print_skip("Access denied - Exiting");
93 exit(KSFT_SKIP);
94 }
95 exit(254);
96 }
97
98 return;
99 }
100