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(reason: Twine(Reason), gen_crash_diag: GenCrashDiag);
84}
85
86void llvm::report_fatal_error(StringRef Reason, bool GenCrashDiag) {
87 report_fatal_error(reason: Twine(Reason), gen_crash_diag: GenCrashDiag);
88}
89
90void llvm::report_fatal_error(const Twine &Reason, bool GenCrashDiag) {
91 llvm::fatal_error_handler_t handler = nullptr;
92 void* handlerData = nullptr;
93 {
94 // Only acquire the mutex while reading the handler, so as not to invoke a
95 // user-supplied callback under a lock.
96#if LLVM_ENABLE_THREADS == 1
97 std::lock_guard<std::mutex> Lock(ErrorHandlerMutex);
98#endif
99 handler = ErrorHandler;
100 handlerData = ErrorHandlerUserData;
101 }
102
103 if (handler) {
104 handler(handlerData, Reason.str().c_str(), GenCrashDiag);
105 } else {
106 // Blast the result out to stderr. We don't try hard to make sure this
107 // succeeds (e.g. handling EINTR) and we can't use errs() here because
108 // raw ostreams can call report_fatal_error.
109 SmallVector<char, 64> Buffer;
110 raw_svector_ostream OS(Buffer);
111 OS << "LLVM ERROR: " << Reason << "\n";
112 StringRef MessageStr = OS.str();
113 ssize_t written = ::write(fd: 2, buf: MessageStr.data(), n: MessageStr.size());
114 (void)written; // If something went wrong, we deliberately just give up.
115 }
116
117 // If we reached here, we are failing ungracefully. Run the interrupt handlers
118 // to make sure any special cleanups get done, in particular that we remove
119 // files registered with RemoveFileOnSignal.
120 sys::RunInterruptHandlers();
121
122 if (GenCrashDiag)
123 abort();
124 else
125 exit(status: 1);
126}
127
128void llvm::install_bad_alloc_error_handler(fatal_error_handler_t handler,
129 void *user_data) {
130#if LLVM_ENABLE_THREADS == 1
131 std::lock_guard<std::mutex> Lock(BadAllocErrorHandlerMutex);
132#endif
133 assert(!BadAllocErrorHandler &&
134 "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 const char *OOMMessage = "LLVM ERROR: out of memory\n";
172 const char *Newline = "\n";
173 (void)!::write(fd: 2, buf: OOMMessage, n: strlen(s: OOMMessage));
174 (void)!::write(fd: 2, buf: Reason, n: strlen(s: Reason));
175 (void)!::write(fd: 2, buf: Newline, n: strlen(s: Newline));
176 abort();
177#endif
178}
179
180#ifdef LLVM_ENABLE_EXCEPTIONS
181// Do not set custom new handler if exceptions are enabled. In this case OOM
182// errors are handled by throwing 'std::bad_alloc'.
183void llvm::install_out_of_memory_new_handler() {
184}
185#else
186// Causes crash on allocation failure. It is called prior to the handler set by
187// 'install_bad_alloc_error_handler'.
188static void out_of_memory_new_handler() {
189 llvm::report_bad_alloc_error(Reason: "Allocation failed");
190}
191
192// Installs new handler that causes crash on allocation failure. It is called by
193// InitLLVM.
194void llvm::install_out_of_memory_new_handler() {
195 std::new_handler old = std::set_new_handler(out_of_memory_new_handler);
196 (void)old;
197 assert((old == nullptr || old == out_of_memory_new_handler) &&
198 "new-handler already installed");
199}
200#endif
201
202void llvm::llvm_unreachable_internal(const char *msg, const char *file,
203 unsigned line) {
204 // This code intentionally doesn't call the ErrorHandler callback, because
205 // llvm_unreachable is intended to be used to indicate "impossible"
206 // situations, and not legitimate runtime errors.
207 if (msg)
208 dbgs() << msg << "\n";
209 dbgs() << "UNREACHABLE executed";
210 if (file)
211 dbgs() << " at " << file << ":" << line;
212 dbgs() << "!\n";
213 abort();
214#ifdef LLVM_BUILTIN_UNREACHABLE
215 // Windows systems and possibly others don't declare abort() to be noreturn,
216 // so use the unreachable builtin to avoid a Clang self-host warning.
217 LLVM_BUILTIN_UNREACHABLE;
218#endif
219}
220
221static void bindingsErrorHandler(void *user_data, const char *reason,
222 bool gen_crash_diag) {
223 LLVMFatalErrorHandler handler =
224 LLVM_EXTENSION reinterpret_cast<LLVMFatalErrorHandler>(user_data);
225 handler(reason);
226}
227
228void LLVMInstallFatalErrorHandler(LLVMFatalErrorHandler Handler) {
229 install_fatal_error_handler(handler: bindingsErrorHandler,
230 LLVM_EXTENSION reinterpret_cast<void *>(Handler));
231}
232
233void LLVMResetFatalErrorHandler() {
234 remove_fatal_error_handler();
235}
236
237#ifdef _WIN32
238
239#define WIN32_NO_STATUS
240#include "llvm/Support/Windows/WindowsSupport.h"
241#undef WIN32_NO_STATUS
242#include <ntstatus.h>
243#include <winerror.h>
244
245// This is equivalent to NtCurrentTeb()->LastStatusValue, but the public
246// _TEB definition does not expose the LastStatusValue field directly.
247// Avoid offsetting into this structure by calling RtlGetLastNtStatus
248// from ntdll.dll.
249//
250// The return of this function will roughly match that of
251// GetLastError, but this lower level API disambiguates some cases
252// that GetLastError does not.
253//
254// For more information, see:
255// https://www.geoffchappell.com/studies/windows/km/ntoskrnl/inc/api/pebteb/teb/index.htm
256// https://github.com/llvm/llvm-project/issues/89137
257extern "C" NTSYSAPI NTSTATUS NTAPI RtlGetLastNtStatus();
258
259// This function obtains the last error code and maps it. It may call
260// RtlGetLastNtStatus, which is a lower level API that can return a
261// more specific error code than GetLastError.
262std::error_code llvm::mapLastWindowsError() {
263 unsigned EV = ::GetLastError();
264 // The mapping of NTSTATUS to Win32 error loses some information; special
265 // case the generic ERROR_ACCESS_DENIED code to check the underlying
266 // NTSTATUS and potentially return a more accurate error code.
267 if (EV == ERROR_ACCESS_DENIED) {
268 llvm::errc code = RtlGetLastNtStatus() == STATUS_DELETE_PENDING
269 ? errc::delete_pending
270 : errc::permission_denied;
271 return make_error_code(code);
272 }
273 return mapWindowsError(EV);
274}
275
276// I'd rather not double the line count of the following.
277#define MAP_ERR_TO_COND(x, y) \
278 case x: \
279 return make_error_code(errc::y)
280
281std::error_code llvm::mapWindowsError(unsigned EV) {
282 switch (EV) {
283 MAP_ERR_TO_COND(ERROR_ACCESS_DENIED, permission_denied);
284 MAP_ERR_TO_COND(ERROR_ALREADY_EXISTS, file_exists);
285 MAP_ERR_TO_COND(ERROR_BAD_NETPATH, no_such_file_or_directory);
286 MAP_ERR_TO_COND(ERROR_BAD_PATHNAME, no_such_file_or_directory);
287 MAP_ERR_TO_COND(ERROR_BAD_UNIT, no_such_device);
288 MAP_ERR_TO_COND(ERROR_BROKEN_PIPE, broken_pipe);
289 MAP_ERR_TO_COND(ERROR_BUFFER_OVERFLOW, filename_too_long);
290 MAP_ERR_TO_COND(ERROR_BUSY, device_or_resource_busy);
291 MAP_ERR_TO_COND(ERROR_BUSY_DRIVE, device_or_resource_busy);
292 MAP_ERR_TO_COND(ERROR_CANNOT_MAKE, permission_denied);
293 MAP_ERR_TO_COND(ERROR_CANTOPEN, io_error);
294 MAP_ERR_TO_COND(ERROR_CANTREAD, io_error);
295 MAP_ERR_TO_COND(ERROR_CANTWRITE, io_error);
296 MAP_ERR_TO_COND(ERROR_CURRENT_DIRECTORY, permission_denied);
297 MAP_ERR_TO_COND(ERROR_DEV_NOT_EXIST, no_such_device);
298 MAP_ERR_TO_COND(ERROR_DEVICE_IN_USE, device_or_resource_busy);
299 MAP_ERR_TO_COND(ERROR_DIR_NOT_EMPTY, directory_not_empty);
300 MAP_ERR_TO_COND(ERROR_DIRECTORY, invalid_argument);
301 MAP_ERR_TO_COND(ERROR_DISK_FULL, no_space_on_device);
302 MAP_ERR_TO_COND(ERROR_FILE_EXISTS, file_exists);
303 MAP_ERR_TO_COND(ERROR_FILE_NOT_FOUND, no_such_file_or_directory);
304 MAP_ERR_TO_COND(ERROR_HANDLE_DISK_FULL, no_space_on_device);
305 MAP_ERR_TO_COND(ERROR_INVALID_ACCESS, permission_denied);
306 MAP_ERR_TO_COND(ERROR_INVALID_DRIVE, no_such_device);
307 MAP_ERR_TO_COND(ERROR_INVALID_FUNCTION, function_not_supported);
308 MAP_ERR_TO_COND(ERROR_INVALID_HANDLE, invalid_argument);
309 MAP_ERR_TO_COND(ERROR_INVALID_NAME, invalid_argument);
310 MAP_ERR_TO_COND(ERROR_INVALID_PARAMETER, invalid_argument);
311 MAP_ERR_TO_COND(ERROR_LOCK_VIOLATION, no_lock_available);
312 MAP_ERR_TO_COND(ERROR_LOCKED, no_lock_available);
313 MAP_ERR_TO_COND(ERROR_NEGATIVE_SEEK, invalid_argument);
314 MAP_ERR_TO_COND(ERROR_NOACCESS, permission_denied);
315 MAP_ERR_TO_COND(ERROR_NOT_ENOUGH_MEMORY, not_enough_memory);
316 MAP_ERR_TO_COND(ERROR_NOT_READY, resource_unavailable_try_again);
317 MAP_ERR_TO_COND(ERROR_NOT_SUPPORTED, not_supported);
318 MAP_ERR_TO_COND(ERROR_OPEN_FAILED, io_error);
319 MAP_ERR_TO_COND(ERROR_OPEN_FILES, device_or_resource_busy);
320 MAP_ERR_TO_COND(ERROR_OUTOFMEMORY, not_enough_memory);
321 MAP_ERR_TO_COND(ERROR_PATH_NOT_FOUND, no_such_file_or_directory);
322 MAP_ERR_TO_COND(ERROR_READ_FAULT, io_error);
323 MAP_ERR_TO_COND(ERROR_REPARSE_TAG_INVALID, invalid_argument);
324 MAP_ERR_TO_COND(ERROR_RETRY, resource_unavailable_try_again);
325 MAP_ERR_TO_COND(ERROR_SEEK, io_error);
326 MAP_ERR_TO_COND(ERROR_SHARING_VIOLATION, permission_denied);
327 MAP_ERR_TO_COND(ERROR_TOO_MANY_OPEN_FILES, too_many_files_open);
328 MAP_ERR_TO_COND(ERROR_WRITE_FAULT, io_error);
329 MAP_ERR_TO_COND(ERROR_WRITE_PROTECT, permission_denied);
330 MAP_ERR_TO_COND(WSAEACCES, permission_denied);
331 MAP_ERR_TO_COND(WSAEBADF, bad_file_descriptor);
332 MAP_ERR_TO_COND(WSAEFAULT, bad_address);
333 MAP_ERR_TO_COND(WSAEINTR, interrupted);
334 MAP_ERR_TO_COND(WSAEINVAL, invalid_argument);
335 MAP_ERR_TO_COND(WSAEMFILE, too_many_files_open);
336 MAP_ERR_TO_COND(WSAENAMETOOLONG, filename_too_long);
337 default:
338 return std::error_code(EV, std::system_category());
339 }
340}
341
342#endif
343