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

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