1//===- lib/Support/ErrorHandling.cpp - Callbacks for errors ---------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines an API used to indicate fatal error conditions.  Non-fatal
10// errors (most of them) should be handled through LLVMContext.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Support/ErrorHandling.h"
15#include "llvm-c/ErrorHandling.h"
16#include "llvm/ADT/SmallVector.h"
17#include "llvm/ADT/Twine.h"
18#include "llvm/Config/config.h"
19#include "llvm/Support/Debug.h"
20#include "llvm/Support/Errc.h"
21#include "llvm/Support/Error.h"
22#include "llvm/Support/Process.h"
23#include "llvm/Support/Signals.h"
24#include "llvm/Support/Threading.h"
25#include "llvm/Support/WindowsError.h"
26#include "llvm/Support/raw_ostream.h"
27#include <cassert>
28#include <cstdlib>
29#include <mutex>
30#include <new>
31
32#if defined(HAVE_UNISTD_H)
33# include <unistd.h>
34#endif
35#if defined(_MSC_VER)
36# include <io.h>
37# include <fcntl.h>
38#endif
39
40using namespace llvm;
41
42static fatal_error_handler_t ErrorHandler = nullptr;
43static void *ErrorHandlerUserData = nullptr;
44
45static fatal_error_handler_t BadAllocErrorHandler = nullptr;
46static void *BadAllocErrorHandlerUserData = nullptr;
47
48#if LLVM_ENABLE_THREADS == 1
49// Mutexes to synchronize installing error handlers and calling error handlers.
50// Do not use ManagedStatic, or that may allocate memory while attempting to
51// report an OOM.
52//
53// This usage of std::mutex has to be conditionalized behind ifdefs because
54// of this script:
55//   compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh
56// That script attempts to statically link the LLVM symbolizer library with the
57// STL and hide all of its symbols with 'opt -internalize'. To reduce size, it
58// cuts out the threading portions of the hermetic copy of libc++ that it
59// builds. We can remove these ifdefs if that script goes away.
60static std::mutex ErrorHandlerMutex;
61static std::mutex BadAllocErrorHandlerMutex;
62#endif
63
64void llvm::install_fatal_error_handler(fatal_error_handler_t handler,
65                                       void *user_data) {
66#if LLVM_ENABLE_THREADS == 1
67  std::lock_guard<std::mutex> Lock(ErrorHandlerMutex);
68#endif
69  assert(!ErrorHandler && "Error handler already registered!\n");
70  ErrorHandler = handler;
71  ErrorHandlerUserData = user_data;
72}
73
74void llvm::remove_fatal_error_handler() {
75#if LLVM_ENABLE_THREADS == 1
76  std::lock_guard<std::mutex> Lock(ErrorHandlerMutex);
77#endif
78  ErrorHandler = nullptr;
79  ErrorHandlerUserData = nullptr;
80}
81
82void llvm::report_fatal_error(const char *Reason, bool GenCrashDiag) {
83  report_fatal_error(Twine(Reason), GenCrashDiag);
84}
85
86void llvm::report_fatal_error(const std::string &Reason, bool GenCrashDiag) {
87  report_fatal_error(Twine(Reason), GenCrashDiag);
88}
89
90void llvm::report_fatal_error(StringRef Reason, bool GenCrashDiag) {
91  report_fatal_error(Twine(Reason), GenCrashDiag);
92}
93
94void llvm::report_fatal_error(const Twine &Reason, bool GenCrashDiag) {
95  llvm::fatal_error_handler_t handler = nullptr;
96  void* handlerData = nullptr;
97  {
98    // Only acquire the mutex while reading the handler, so as not to invoke a
99    // user-supplied callback under a lock.
100#if LLVM_ENABLE_THREADS == 1
101    std::lock_guard<std::mutex> Lock(ErrorHandlerMutex);
102#endif
103    handler = ErrorHandler;
104    handlerData = ErrorHandlerUserData;
105  }
106
107  if (handler) {
108    handler(handlerData, Reason.str(), GenCrashDiag);
109  } else {
110    // Blast the result out to stderr.  We don't try hard to make sure this
111    // succeeds (e.g. handling EINTR) and we can't use errs() here because
112    // raw ostreams can call report_fatal_error.
113    SmallVector<char, 64> Buffer;
114    raw_svector_ostream OS(Buffer);
115    OS << "LLVM ERROR: " << Reason << "\n";
116    StringRef MessageStr = OS.str();
117    ssize_t written = ::write(2, MessageStr.data(), MessageStr.size());
118    (void)written; // If something went wrong, we deliberately just give up.
119  }
120
121  // If we reached here, we are failing ungracefully. Run the interrupt handlers
122  // to make sure any special cleanups get done, in particular that we remove
123  // files registered with RemoveFileOnSignal.
124  sys::RunInterruptHandlers();
125
126  sys::Process::Exit(1);
127}
128
129void llvm::install_bad_alloc_error_handler(fatal_error_handler_t handler,
130                                           void *user_data) {
131#if LLVM_ENABLE_THREADS == 1
132  std::lock_guard<std::mutex> Lock(BadAllocErrorHandlerMutex);
133#endif
134  assert(!ErrorHandler && "Bad alloc error handler already registered!\n");
135  BadAllocErrorHandler = handler;
136  BadAllocErrorHandlerUserData = user_data;
137}
138
139void llvm::remove_bad_alloc_error_handler() {
140#if LLVM_ENABLE_THREADS == 1
141  std::lock_guard<std::mutex> Lock(BadAllocErrorHandlerMutex);
142#endif
143  BadAllocErrorHandler = nullptr;
144  BadAllocErrorHandlerUserData = nullptr;
145}
146
147void llvm::report_bad_alloc_error(const char *Reason, bool GenCrashDiag) {
148  fatal_error_handler_t Handler = nullptr;
149  void *HandlerData = nullptr;
150  {
151    // Only acquire the mutex while reading the handler, so as not to invoke a
152    // user-supplied callback under a lock.
153#if LLVM_ENABLE_THREADS == 1
154    std::lock_guard<std::mutex> Lock(BadAllocErrorHandlerMutex);
155#endif
156    Handler = BadAllocErrorHandler;
157    HandlerData = BadAllocErrorHandlerUserData;
158  }
159
160  if (Handler) {
161    Handler(HandlerData, Reason, GenCrashDiag);
162    llvm_unreachable("bad alloc handler should not return");
163  }
164
165#ifdef LLVM_ENABLE_EXCEPTIONS
166  // If exceptions are enabled, make OOM in malloc look like OOM in new.
167  throw std::bad_alloc();
168#else
169  // Don't call the normal error handler. It may allocate memory. Directly write
170  // an OOM to stderr and abort.
171  char OOMMessage[] = "LLVM ERROR: out of memory\n";
172  ssize_t written = ::write(2, OOMMessage, strlen(OOMMessage));
173  (void)written;
174  abort();
175#endif
176}
177
178#ifdef LLVM_ENABLE_EXCEPTIONS
179// Do not set custom new handler if exceptions are enabled. In this case OOM
180// errors are handled by throwing 'std::bad_alloc'.
181void llvm::install_out_of_memory_new_handler() {
182}
183#else
184// Causes crash on allocation failure. It is called prior to the handler set by
185// 'install_bad_alloc_error_handler'.
186static void out_of_memory_new_handler() {
187  llvm::report_bad_alloc_error("Allocation failed");
188}
189
190// Installs new handler that causes crash on allocation failure. It is called by
191// InitLLVM.
192void llvm::install_out_of_memory_new_handler() {
193  std::new_handler old = std::set_new_handler(out_of_memory_new_handler);
194  (void)old;
195  assert(old == nullptr && "new-handler already installed");
196}
197#endif
198
199void llvm::llvm_unreachable_internal(const char *msg, const char *file,
200                                     unsigned line) {
201  // This code intentionally doesn't call the ErrorHandler callback, because
202  // llvm_unreachable is intended to be used to indicate "impossible"
203  // situations, and not legitimate runtime errors.
204  if (msg)
205    dbgs() << msg << "\n";
206  dbgs() << "UNREACHABLE executed";
207  if (file)
208    dbgs() << " at " << file << ":" << line;
209  dbgs() << "!\n";
210  abort();
211#ifdef LLVM_BUILTIN_UNREACHABLE
212  // Windows systems and possibly others don't declare abort() to be noreturn,
213  // so use the unreachable builtin to avoid a Clang self-host warning.
214  LLVM_BUILTIN_UNREACHABLE;
215#endif
216}
217
218static void bindingsErrorHandler(void *user_data, const std::string& reason,
219                                 bool gen_crash_diag) {
220  LLVMFatalErrorHandler handler =
221      LLVM_EXTENSION reinterpret_cast<LLVMFatalErrorHandler>(user_data);
222  handler(reason.c_str());
223}
224
225void LLVMInstallFatalErrorHandler(LLVMFatalErrorHandler Handler) {
226  install_fatal_error_handler(bindingsErrorHandler,
227                              LLVM_EXTENSION reinterpret_cast<void *>(Handler));
228}
229
230void LLVMResetFatalErrorHandler() {
231  remove_fatal_error_handler();
232}
233
234#ifdef _WIN32
235
236#include <winerror.h>
237
238// I'd rather not double the line count of the following.
239#define MAP_ERR_TO_COND(x, y)                                                  \
240  case x:                                                                      \
241    return make_error_code(errc::y)
242
243std::error_code llvm::mapWindowsError(unsigned EV) {
244  switch (EV) {
245    MAP_ERR_TO_COND(ERROR_ACCESS_DENIED, permission_denied);
246    MAP_ERR_TO_COND(ERROR_ALREADY_EXISTS, file_exists);
247    MAP_ERR_TO_COND(ERROR_BAD_UNIT, no_such_device);
248    MAP_ERR_TO_COND(ERROR_BUFFER_OVERFLOW, filename_too_long);
249    MAP_ERR_TO_COND(ERROR_BUSY, device_or_resource_busy);
250    MAP_ERR_TO_COND(ERROR_BUSY_DRIVE, device_or_resource_busy);
251    MAP_ERR_TO_COND(ERROR_CANNOT_MAKE, permission_denied);
252    MAP_ERR_TO_COND(ERROR_CANTOPEN, io_error);
253    MAP_ERR_TO_COND(ERROR_CANTREAD, io_error);
254    MAP_ERR_TO_COND(ERROR_CANTWRITE, io_error);
255    MAP_ERR_TO_COND(ERROR_CURRENT_DIRECTORY, permission_denied);
256    MAP_ERR_TO_COND(ERROR_DEV_NOT_EXIST, no_such_device);
257    MAP_ERR_TO_COND(ERROR_DEVICE_IN_USE, device_or_resource_busy);
258    MAP_ERR_TO_COND(ERROR_DIR_NOT_EMPTY, directory_not_empty);
259    MAP_ERR_TO_COND(ERROR_DIRECTORY, invalid_argument);
260    MAP_ERR_TO_COND(ERROR_DISK_FULL, no_space_on_device);
261    MAP_ERR_TO_COND(ERROR_FILE_EXISTS, file_exists);
262    MAP_ERR_TO_COND(ERROR_FILE_NOT_FOUND, no_such_file_or_directory);
263    MAP_ERR_TO_COND(ERROR_HANDLE_DISK_FULL, no_space_on_device);
264    MAP_ERR_TO_COND(ERROR_INVALID_ACCESS, permission_denied);
265    MAP_ERR_TO_COND(ERROR_INVALID_DRIVE, no_such_device);
266    MAP_ERR_TO_COND(ERROR_INVALID_FUNCTION, function_not_supported);
267    MAP_ERR_TO_COND(ERROR_INVALID_HANDLE, invalid_argument);
268    MAP_ERR_TO_COND(ERROR_INVALID_NAME, invalid_argument);
269    MAP_ERR_TO_COND(ERROR_LOCK_VIOLATION, no_lock_available);
270    MAP_ERR_TO_COND(ERROR_LOCKED, no_lock_available);
271    MAP_ERR_TO_COND(ERROR_NEGATIVE_SEEK, invalid_argument);
272    MAP_ERR_TO_COND(ERROR_NOACCESS, permission_denied);
273    MAP_ERR_TO_COND(ERROR_NOT_ENOUGH_MEMORY, not_enough_memory);
274    MAP_ERR_TO_COND(ERROR_NOT_READY, resource_unavailable_try_again);
275    MAP_ERR_TO_COND(ERROR_OPEN_FAILED, io_error);
276    MAP_ERR_TO_COND(ERROR_OPEN_FILES, device_or_resource_busy);
277    MAP_ERR_TO_COND(ERROR_OUTOFMEMORY, not_enough_memory);
278    MAP_ERR_TO_COND(ERROR_PATH_NOT_FOUND, no_such_file_or_directory);
279    MAP_ERR_TO_COND(ERROR_BAD_NETPATH, no_such_file_or_directory);
280    MAP_ERR_TO_COND(ERROR_READ_FAULT, io_error);
281    MAP_ERR_TO_COND(ERROR_RETRY, resource_unavailable_try_again);
282    MAP_ERR_TO_COND(ERROR_SEEK, io_error);
283    MAP_ERR_TO_COND(ERROR_SHARING_VIOLATION, permission_denied);
284    MAP_ERR_TO_COND(ERROR_TOO_MANY_OPEN_FILES, too_many_files_open);
285    MAP_ERR_TO_COND(ERROR_WRITE_FAULT, io_error);
286    MAP_ERR_TO_COND(ERROR_WRITE_PROTECT, permission_denied);
287    MAP_ERR_TO_COND(WSAEACCES, permission_denied);
288    MAP_ERR_TO_COND(WSAEBADF, bad_file_descriptor);
289    MAP_ERR_TO_COND(WSAEFAULT, bad_address);
290    MAP_ERR_TO_COND(WSAEINTR, interrupted);
291    MAP_ERR_TO_COND(WSAEINVAL, invalid_argument);
292    MAP_ERR_TO_COND(WSAEMFILE, too_many_files_open);
293    MAP_ERR_TO_COND(WSAENAMETOOLONG, filename_too_long);
294  default:
295    return std::error_code(EV, std::system_category());
296  }
297}
298
299#endif
300