kvm/lib/assert.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * tools/testing/selftests/kvm/lib/assert.c
0004  *
0005  * Copyright (C) 2018, Google LLC.
0006  */
0007
0008 #define _GNU_SOURCE /* for getline(3) and strchrnul(3)*/
0009
0010 #include "test_util.h"
0011
0012 #include <execinfo.h>
0013 #include <sys/syscall.h>
0014
0015 #include "kselftest.h"
0016
0017 /* Dumps the current stack trace to stderr. */
0018 static void __attribute__((noinline)) test_dump_stack(void);
0019 static void test_dump_stack(void)
0020 {
0021     /*
0022      * Build and run this command:
0023      *
0024      *  addr2line -s -e /proc/$PPID/exe -fpai {backtrace addresses} | \
0025      *      cat -n 1>&2
0026      *
0027      * Note that the spacing is different and there's no newline.
0028      */
0029     size_t i;
0030     size_t n = 20;
0031     void *stack[n];
0032     const char *addr2line = "addr2line -s -e /proc/$PPID/exe -fpai";
0033     const char *pipeline = "|cat -n 1>&2";
0034     char cmd[strlen(addr2line) + strlen(pipeline) +
0035          /* N bytes per addr * 2 digits per byte + 1 space per addr: */
0036          n * (((sizeof(void *)) * 2) + 1) +
0037          /* Null terminator: */
0038          1];
0039     char *c = cmd;
0040
0041     n = backtrace(stack, n);
0042     /*
0043      * Skip the first 2 frames, which should be test_dump_stack() and
0044      * test_assert(); both of which are declared noinline.  Bail if the
0045      * resulting stack trace would be empty. Otherwise, addr2line will block
0046      * waiting for addresses to be passed in via stdin.
0047      */
0048     if (n <= 2) {
0049         fputs("  (stack trace empty)\n", stderr);
0050         return;
0051     }
0052
0053     c += sprintf(c, "%s", addr2line);
0054     for (i = 2; i < n; i++)
0055         c += sprintf(c, " %lx", ((unsigned long) stack[i]) - 1);
0056
0057     c += sprintf(c, "%s", pipeline);
0058 #pragma GCC diagnostic push
0059 #pragma GCC diagnostic ignored "-Wunused-result"
0060     system(cmd);
0061 #pragma GCC diagnostic pop
0062 }
0063
0064 static pid_t _gettid(void)
0065 {
0066     return syscall(SYS_gettid);
0067 }
0068
0069 void __attribute__((noinline))
0070 test_assert(bool exp, const char *exp_str,
0071     const char *file, unsigned int line, const char *fmt, ...)
0072 {
0073     va_list ap;
0074
0075     if (!(exp)) {
0076         va_start(ap, fmt);
0077
0078         fprintf(stderr, "==== Test Assertion Failure ====\n"
0079             "  %s:%u: %s\n"
0080             "  pid=%d tid=%d errno=%d - %s\n",
0081             file, line, exp_str, getpid(), _gettid(),
0082             errno, strerror(errno));
0083         test_dump_stack();
0084         if (fmt) {
0085             fputs("  ", stderr);
0086             vfprintf(stderr, fmt, ap);
0087             fputs("\n", stderr);
0088         }
0089         va_end(ap);
0090
0091         if (errno == EACCES) {
0092             print_skip("Access denied - Exiting");
0093             exit(KSFT_SKIP);
0094         }
0095         exit(254);
0096     }
0097
0098     return;
0099 }