1 //===-- Status.cpp --------------------------------------------------------===//
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 #include "lldb/Utility/Status.h"
10 
11 #include "lldb/Utility/VASPrintf.h"
12 #include "lldb/lldb-defines.h"
13 #include "lldb/lldb-enumerations.h"
14 #include "llvm/ADT/SmallString.h"
15 #include "llvm/ADT/StringRef.h"
16 #include "llvm/Support/Errno.h"
17 #include "llvm/Support/FormatProviders.h"
18 
19 #include <cerrno>
20 #include <cstdarg>
21 #include <string>
22 #include <system_error>
23 
24 #ifdef __APPLE__
25 #include <mach/mach.h>
26 #endif
27 
28 #ifdef _WIN32
29 #include <windows.h>
30 #endif
31 #include <cstdint>
32 
33 namespace llvm {
34 class raw_ostream;
35 }
36 
37 using namespace lldb;
38 using namespace lldb_private;
39 
40 Status::Status() : m_string() {}
41 
42 Status::Status(ValueType err, ErrorType type)
43     : m_code(err), m_type(type), m_string() {}
44 
45 // This logic is confusing because c++ calls the traditional (posix) errno codes
46 // "generic errors", while we use the term "generic" to mean completely
47 // arbitrary (text-based) errors.
48 Status::Status(std::error_code EC)
49     : m_code(EC.value()),
50       m_type(EC.category() == std::generic_category() ? eErrorTypePOSIX
51                                                       : eErrorTypeGeneric),
52       m_string(EC.message()) {}
53 
54 Status::Status(const char *format, ...) : m_string() {
55   va_list args;
56   va_start(args, format);
57   SetErrorToGenericError();
58   SetErrorStringWithVarArg(format, args);
59   va_end(args);
60 }
61 
62 const Status &Status::operator=(llvm::Error error) {
63   if (!error) {
64     Clear();
65     return *this;
66   }
67 
68   // if the error happens to be a errno error, preserve the error code
69   error = llvm::handleErrors(
70       std::move(error), [&](std::unique_ptr<llvm::ECError> e) -> llvm::Error {
71         std::error_code ec = e->convertToErrorCode();
72         if (ec.category() == std::generic_category()) {
73           m_code = ec.value();
74           m_type = ErrorType::eErrorTypePOSIX;
75           return llvm::Error::success();
76         }
77         return llvm::Error(std::move(e));
78       });
79 
80   // Otherwise, just preserve the message
81   if (error) {
82     SetErrorToGenericError();
83     SetErrorString(llvm::toString(std::move(error)));
84   }
85 
86   return *this;
87 }
88 
89 llvm::Error Status::ToError() const {
90   if (Success())
91     return llvm::Error::success();
92   if (m_type == ErrorType::eErrorTypePOSIX)
93     return llvm::errorCodeToError(
94         std::error_code(m_code, std::generic_category()));
95   return llvm::make_error<llvm::StringError>(AsCString(),
96                                              llvm::inconvertibleErrorCode());
97 }
98 
99 Status::~Status() = default;
100 
101 #ifdef _WIN32
102 static std::string RetrieveWin32ErrorString(uint32_t error_code) {
103   char *buffer = nullptr;
104   std::string message;
105   // Retrieve win32 system error.
106   // First, attempt to load a en-US message
107   if (::FormatMessageA(
108           FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
109               FORMAT_MESSAGE_MAX_WIDTH_MASK,
110           NULL, error_code, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
111           (LPSTR)&buffer, 0, NULL)) {
112     message.assign(buffer);
113     ::LocalFree(buffer);
114   }
115   // If the previous didn't work, use the default OS language
116   else if (::FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
117                                 FORMAT_MESSAGE_FROM_SYSTEM |
118                                 FORMAT_MESSAGE_MAX_WIDTH_MASK,
119                             NULL, error_code, 0, (LPSTR)&buffer, 0, NULL)) {
120     message.assign(buffer);
121     ::LocalFree(buffer);
122   }
123   return message;
124 }
125 #endif
126 
127 // Get the error value as a NULL C string. The error string will be fetched and
128 // cached on demand. The cached error string value will remain until the error
129 // value is changed or cleared.
130 const char *Status::AsCString(const char *default_error_str) const {
131   if (Success())
132     return nullptr;
133 
134   if (m_string.empty()) {
135     switch (m_type) {
136     case eErrorTypeMachKernel:
137 #if defined(__APPLE__)
138       if (const char *s = ::mach_error_string(m_code))
139         m_string.assign(s);
140 #endif
141       break;
142 
143     case eErrorTypePOSIX:
144       m_string = llvm::sys::StrError(m_code);
145       break;
146 
147     case eErrorTypeWin32:
148 #if defined(_WIN32)
149       m_string = RetrieveWin32ErrorString(m_code);
150 #endif
151       break;
152 
153     default:
154       break;
155     }
156   }
157   if (m_string.empty()) {
158     if (default_error_str)
159       m_string.assign(default_error_str);
160     else
161       return nullptr; // User wanted a nullptr string back...
162   }
163   return m_string.c_str();
164 }
165 
166 // Clear the error and any cached error string that it might contain.
167 void Status::Clear() {
168   m_code = 0;
169   m_type = eErrorTypeInvalid;
170   m_string.clear();
171 }
172 
173 // Access the error value.
174 Status::ValueType Status::GetError() const { return m_code; }
175 
176 // Access the error type.
177 ErrorType Status::GetType() const { return m_type; }
178 
179 // Returns true if this object contains a value that describes an error or
180 // otherwise non-success result.
181 bool Status::Fail() const { return m_code != 0; }
182 
183 // Set accessor for the error value to "err" and the type to
184 // "eErrorTypeMachKernel"
185 void Status::SetMachError(uint32_t err) {
186   m_code = err;
187   m_type = eErrorTypeMachKernel;
188   m_string.clear();
189 }
190 
191 void Status::SetExpressionError(lldb::ExpressionResults result,
192                                 const char *mssg) {
193   m_code = result;
194   m_type = eErrorTypeExpression;
195   m_string = mssg;
196 }
197 
198 int Status::SetExpressionErrorWithFormat(lldb::ExpressionResults result,
199                                          const char *format, ...) {
200   int length = 0;
201 
202   if (format != nullptr && format[0]) {
203     va_list args;
204     va_start(args, format);
205     length = SetErrorStringWithVarArg(format, args);
206     va_end(args);
207   } else {
208     m_string.clear();
209   }
210   m_code = result;
211   m_type = eErrorTypeExpression;
212   return length;
213 }
214 
215 // Set accessor for the error value and type.
216 void Status::SetError(ValueType err, ErrorType type) {
217   m_code = err;
218   m_type = type;
219   m_string.clear();
220 }
221 
222 // Update the error value to be "errno" and update the type to be "POSIX".
223 void Status::SetErrorToErrno() {
224   m_code = errno;
225   m_type = eErrorTypePOSIX;
226   m_string.clear();
227 }
228 
229 // Update the error value to be LLDB_GENERIC_ERROR and update the type to be
230 // "Generic".
231 void Status::SetErrorToGenericError() {
232   m_code = LLDB_GENERIC_ERROR;
233   m_type = eErrorTypeGeneric;
234   m_string.clear();
235 }
236 
237 // Set accessor for the error string value for a specific error. This allows
238 // any string to be supplied as an error explanation. The error string value
239 // will remain until the error value is cleared or a new error value/type is
240 // assigned.
241 void Status::SetErrorString(llvm::StringRef err_str) {
242   if (!err_str.empty()) {
243     // If we have an error string, we should always at least have an error set
244     // to a generic value.
245     if (Success())
246       SetErrorToGenericError();
247   }
248   m_string = std::string(err_str);
249 }
250 
251 /// Set the current error string to a formatted error string.
252 ///
253 /// \param format
254 ///     A printf style format string
255 int Status::SetErrorStringWithFormat(const char *format, ...) {
256   if (format != nullptr && format[0]) {
257     va_list args;
258     va_start(args, format);
259     int length = SetErrorStringWithVarArg(format, args);
260     va_end(args);
261     return length;
262   } else {
263     m_string.clear();
264   }
265   return 0;
266 }
267 
268 int Status::SetErrorStringWithVarArg(const char *format, va_list args) {
269   if (format != nullptr && format[0]) {
270     // If we have an error string, we should always at least have an error set
271     // to a generic value.
272     if (Success())
273       SetErrorToGenericError();
274 
275     llvm::SmallString<1024> buf;
276     VASprintf(buf, format, args);
277     m_string = std::string(buf.str());
278     return buf.size();
279   } else {
280     m_string.clear();
281   }
282   return 0;
283 }
284 
285 // Returns true if the error code in this object is considered a successful
286 // return value.
287 bool Status::Success() const { return m_code == 0; }
288 
289 void llvm::format_provider<lldb_private::Status>::format(
290     const lldb_private::Status &error, llvm::raw_ostream &OS,
291     llvm::StringRef Options) {
292   llvm::format_provider<llvm::StringRef>::format(error.AsCString(), OS,
293                                                  Options);
294 }
295