/* * tools/testing/selftests/kvm/lib/assert.c * * Copyright (C) 2018, Google LLC. * * This work is licensed under the terms of the GNU GPL, version 2. */ #define _GNU_SOURCE /* for getline(3) and strchrnul(3)*/ #include "test_util.h" #include <execinfo.h> #include <sys/syscall.h> #include "kselftest.h" /* Dumps the current stack trace to stderr. */ static void __attribute__((noinline)) test_dump_stack(void); static void test_dump_stack(void) { /* * Build and run this command: * * addr2line -s -e /proc/$PPID/exe -fpai {backtrace addresses} | \ * grep -v test_dump_stack | cat -n 1>&2 * * Note that the spacing is different and there's no newline. */ size_t i; size_t n = 20; void *stack[n]; const char *addr2line = "addr2line -s -e /proc/$PPID/exe -fpai"; const char *pipeline = "|cat -n 1>&2"; char cmd[strlen(addr2line) + strlen(pipeline) + /* N bytes per addr * 2 digits per byte + 1 space per addr: */ n * (((sizeof(void *)) * 2) + 1) + /* Null terminator: */ 1]; char *c; n = backtrace(stack, n); c = &cmd[0]; c += sprintf(c, "%s", addr2line); /* * Skip the first 3 frames: backtrace, test_dump_stack, and * test_assert. We hope that backtrace isn't inlined and the other two * we've declared noinline. */ for (i = 2; i < n; i++) c += sprintf(c, " %lx", ((unsigned long) stack[i]) - 1); c += sprintf(c, "%s", pipeline); #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wunused-result" system(cmd); #pragma GCC diagnostic pop } static pid_t gettid(void) { return syscall(SYS_gettid); } void __attribute__((noinline)) test_assert(bool exp, const char *exp_str, const char *file, unsigned int line, const char *fmt, ...) { va_list ap; if (!(exp)) { va_start(ap, fmt); fprintf(stderr, "==== Test Assertion Failure ====\n" " %s:%u: %s\n" " pid=%d tid=%d - %s\n", file, line, exp_str, getpid(), gettid(), strerror(errno)); test_dump_stack(); if (fmt) { fputs(" ", stderr); vfprintf(stderr, fmt, ap); fputs("\n", stderr); } va_end(ap); if (errno == EACCES) ksft_exit_skip("Access denied - Exiting.\n"); exit(254); } return; }