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); 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 64 static pid_t _gettid(void) 65 { 66 return syscall(SYS_gettid); 67 } 68 69 void __attribute__((noinline)) 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