tools/testing/selftests/kvm/lib/assert.c

   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 #include "test_util.h"
   8
   9 #include <execinfo.h>
  10 #include <sys/syscall.h>
  11
  12 #include "kselftest.h"
  13
  14 /* Dumps the current stack trace to stderr. */
  15 static void __attribute__((noinline)) test_dump_stack(void);
  16 static void test_dump_stack(void)
  17 {
  18         /*
  19          * Build and run this command:
  20          *
  21          *      addr2line -s -e /proc/$PPID/exe -fpai {backtrace addresses} | \
  22          *              cat -n 1>&2
  23          *
  24          * Note that the spacing is different and there's no newline.
  25          */
  26         size_t i;
  27         size_t n = 20;
  28         void *stack[n];
  29         const char *addr2line = "addr2line -s -e /proc/$PPID/exe -fpai";
  30         const char *pipeline = "|cat -n 1>&2";
  31         char cmd[strlen(addr2line) + strlen(pipeline) +
  32                  /* N bytes per addr * 2 digits per byte + 1 space per addr: */
  33                  n * (((sizeof(void *)) * 2) + 1) +
  34                  /* Null terminator: */
  35                  1];
  36         char *c = cmd;
  37
  38         n = backtrace(stack, n);
  39         /*
  40          * Skip the first 2 frames, which should be test_dump_stack() and
  41          * test_assert(); both of which are declared noinline.  Bail if the
  42          * resulting stack trace would be empty. Otherwise, addr2line will block
  43          * waiting for addresses to be passed in via stdin.
  44          */
  45         if (n <= 2) {
  46                 fputs("  (stack trace empty)\n", stderr);
  47                 return;
  48         }
  49
  50         c += sprintf(c, "%s", addr2line);
  51         for (i = 2; i < n; i++)
  52                 c += sprintf(c, " %lx", ((unsigned long) stack[i]) - 1);
  53
  54         c += sprintf(c, "%s", pipeline);
  55 #pragma GCC diagnostic push
  56 #pragma GCC diagnostic ignored "-Wunused-result"
  57         system(cmd);
  58 #pragma GCC diagnostic pop
  59 }
  60
  61 static pid_t _gettid(void)
  62 {
  63         return syscall(SYS_gettid);
  64 }
  65
  66 void __attribute__((noinline))
  67 test_assert(bool exp, const char *exp_str,
  68         const char *file, unsigned int line, const char *fmt, ...)
  69 {
  70         va_list ap;
  71
  72         if (!(exp)) {
  73                 va_start(ap, fmt);
  74
  75                 fprintf(stderr, "==== Test Assertion Failure ====\n"
  76                         "  %s:%u: %s\n"
  77                         "  pid=%d tid=%d errno=%d - %s\n",
  78                         file, line, exp_str, getpid(), _gettid(),
  79                         errno, strerror(errno));
  80                 test_dump_stack();
  81                 if (fmt) {
  82                         fputs("  ", stderr);
  83                         vfprintf(stderr, fmt, ap);
  84                         fputs("\n", stderr);
  85                 }
  86                 va_end(ap);
  87
  88                 if (errno == EACCES) {
  89                         print_skip("Access denied - Exiting");
  90                         exit(KSFT_SKIP);
  91                 }
  92                 exit(254);
  93         }
  94
  95         return;
  96 }