1 //===- Support/FileUtilities.cpp - File System Utilities ------------------===// 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 implements a family of utility functions which are useful for doing 10 // various things with files. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/FileUtilities.h" 15 #include "llvm/ADT/SmallString.h" 16 #include "llvm/ADT/StringExtras.h" 17 #include "llvm/Support/Error.h" 18 #include "llvm/Support/ErrorOr.h" 19 #include "llvm/Support/MemoryBuffer.h" 20 #include "llvm/Support/Process.h" 21 #include "llvm/Support/raw_ostream.h" 22 #include <cmath> 23 #include <cstdint> 24 #include <cstdlib> 25 #include <cstring> 26 #include <memory> 27 #include <system_error> 28 29 using namespace llvm; 30 31 static bool isSignedChar(char C) { 32 return (C == '+' || C == '-'); 33 } 34 35 static bool isExponentChar(char C) { 36 switch (C) { 37 case 'D': // Strange exponential notation. 38 case 'd': // Strange exponential notation. 39 case 'e': 40 case 'E': return true; 41 default: return false; 42 } 43 } 44 45 static bool isNumberChar(char C) { 46 switch (C) { 47 case '0': case '1': case '2': case '3': case '4': 48 case '5': case '6': case '7': case '8': case '9': 49 case '.': return true; 50 default: return isSignedChar(C) || isExponentChar(C); 51 } 52 } 53 54 static const char *BackupNumber(const char *Pos, const char *FirstChar) { 55 // If we didn't stop in the middle of a number, don't backup. 56 if (!isNumberChar(*Pos)) return Pos; 57 58 // Otherwise, return to the start of the number. 59 bool HasPeriod = false; 60 while (Pos > FirstChar && isNumberChar(Pos[-1])) { 61 // Backup over at most one period. 62 if (Pos[-1] == '.') { 63 if (HasPeriod) 64 break; 65 HasPeriod = true; 66 } 67 68 --Pos; 69 if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1])) 70 break; 71 } 72 return Pos; 73 } 74 75 /// EndOfNumber - Return the first character that is not part of the specified 76 /// number. This assumes that the buffer is null terminated, so it won't fall 77 /// off the end. 78 static const char *EndOfNumber(const char *Pos) { 79 while (isNumberChar(*Pos)) 80 ++Pos; 81 return Pos; 82 } 83 84 /// CompareNumbers - compare two numbers, returning true if they are different. 85 static bool CompareNumbers(const char *&F1P, const char *&F2P, 86 const char *F1End, const char *F2End, 87 double AbsTolerance, double RelTolerance, 88 std::string *ErrorMsg) { 89 const char *F1NumEnd, *F2NumEnd; 90 double V1 = 0.0, V2 = 0.0; 91 92 // If one of the positions is at a space and the other isn't, chomp up 'til 93 // the end of the space. 94 while (isSpace(static_cast<unsigned char>(*F1P)) && F1P != F1End) 95 ++F1P; 96 while (isSpace(static_cast<unsigned char>(*F2P)) && F2P != F2End) 97 ++F2P; 98 99 // If we stop on numbers, compare their difference. 100 if (!isNumberChar(*F1P) || !isNumberChar(*F2P)) { 101 // The diff failed. 102 F1NumEnd = F1P; 103 F2NumEnd = F2P; 104 } else { 105 // Note that some ugliness is built into this to permit support for numbers 106 // that use "D" or "d" as their exponential marker, e.g. "1.234D45". This 107 // occurs in 200.sixtrack in spec2k. 108 V1 = strtod(F1P, const_cast<char**>(&F1NumEnd)); 109 V2 = strtod(F2P, const_cast<char**>(&F2NumEnd)); 110 111 if (*F1NumEnd == 'D' || *F1NumEnd == 'd') { 112 // Copy string into tmp buffer to replace the 'D' with an 'e'. 113 SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1); 114 // Strange exponential notation! 115 StrTmp[static_cast<unsigned>(F1NumEnd-F1P)] = 'e'; 116 117 V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd)); 118 F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]); 119 } 120 121 if (*F2NumEnd == 'D' || *F2NumEnd == 'd') { 122 // Copy string into tmp buffer to replace the 'D' with an 'e'. 123 SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1); 124 // Strange exponential notation! 125 StrTmp[static_cast<unsigned>(F2NumEnd-F2P)] = 'e'; 126 127 V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd)); 128 F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]); 129 } 130 } 131 132 if (F1NumEnd == F1P || F2NumEnd == F2P) { 133 if (ErrorMsg) { 134 *ErrorMsg = "FP Comparison failed, not a numeric difference between '"; 135 *ErrorMsg += F1P[0]; 136 *ErrorMsg += "' and '"; 137 *ErrorMsg += F2P[0]; 138 *ErrorMsg += "'"; 139 } 140 return true; 141 } 142 143 // Check to see if these are inside the absolute tolerance 144 if (AbsTolerance < std::abs(V1-V2)) { 145 // Nope, check the relative tolerance... 146 double Diff; 147 if (V2) 148 Diff = std::abs(V1/V2 - 1.0); 149 else if (V1) 150 Diff = std::abs(V2/V1 - 1.0); 151 else 152 Diff = 0; // Both zero. 153 if (Diff > RelTolerance) { 154 if (ErrorMsg) { 155 raw_string_ostream(*ErrorMsg) 156 << "Compared: " << V1 << " and " << V2 << '\n' 157 << "abs. diff = " << std::abs(V1-V2) << " rel.diff = " << Diff << '\n' 158 << "Out of tolerance: rel/abs: " << RelTolerance << '/' 159 << AbsTolerance; 160 } 161 return true; 162 } 163 } 164 165 // Otherwise, advance our read pointers to the end of the numbers. 166 F1P = F1NumEnd; F2P = F2NumEnd; 167 return false; 168 } 169 170 /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the 171 /// files match, 1 if they are different, and 2 if there is a file error. This 172 /// function differs from DiffFiles in that you can specify an absolete and 173 /// relative FP error that is allowed to exist. If you specify a string to fill 174 /// in for the error option, it will set the string to an error message if an 175 /// error occurs, allowing the caller to distinguish between a failed diff and a 176 /// file system error. 177 /// 178 int llvm::DiffFilesWithTolerance(StringRef NameA, 179 StringRef NameB, 180 double AbsTol, double RelTol, 181 std::string *Error) { 182 // Now its safe to mmap the files into memory because both files 183 // have a non-zero size. 184 ErrorOr<std::unique_ptr<MemoryBuffer>> F1OrErr = MemoryBuffer::getFile(NameA); 185 if (std::error_code EC = F1OrErr.getError()) { 186 if (Error) 187 *Error = EC.message(); 188 return 2; 189 } 190 MemoryBuffer &F1 = *F1OrErr.get(); 191 192 ErrorOr<std::unique_ptr<MemoryBuffer>> F2OrErr = MemoryBuffer::getFile(NameB); 193 if (std::error_code EC = F2OrErr.getError()) { 194 if (Error) 195 *Error = EC.message(); 196 return 2; 197 } 198 MemoryBuffer &F2 = *F2OrErr.get(); 199 200 // Okay, now that we opened the files, scan them for the first difference. 201 const char *File1Start = F1.getBufferStart(); 202 const char *File2Start = F2.getBufferStart(); 203 const char *File1End = F1.getBufferEnd(); 204 const char *File2End = F2.getBufferEnd(); 205 const char *F1P = File1Start; 206 const char *F2P = File2Start; 207 uint64_t A_size = F1.getBufferSize(); 208 uint64_t B_size = F2.getBufferSize(); 209 210 // Are the buffers identical? Common case: Handle this efficiently. 211 if (A_size == B_size && 212 std::memcmp(File1Start, File2Start, A_size) == 0) 213 return 0; 214 215 // Otherwise, we are done a tolerances are set. 216 if (AbsTol == 0 && RelTol == 0) { 217 if (Error) 218 *Error = "Files differ without tolerance allowance"; 219 return 1; // Files different! 220 } 221 222 bool CompareFailed = false; 223 while (true) { 224 // Scan for the end of file or next difference. 225 while (F1P < File1End && F2P < File2End && *F1P == *F2P) { 226 ++F1P; 227 ++F2P; 228 } 229 230 if (F1P >= File1End || F2P >= File2End) break; 231 232 // Okay, we must have found a difference. Backup to the start of the 233 // current number each stream is at so that we can compare from the 234 // beginning. 235 F1P = BackupNumber(F1P, File1Start); 236 F2P = BackupNumber(F2P, File2Start); 237 238 // Now that we are at the start of the numbers, compare them, exiting if 239 // they don't match. 240 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) { 241 CompareFailed = true; 242 break; 243 } 244 } 245 246 // Okay, we reached the end of file. If both files are at the end, we 247 // succeeded. 248 bool F1AtEnd = F1P >= File1End; 249 bool F2AtEnd = F2P >= File2End; 250 if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) { 251 // Else, we might have run off the end due to a number: backup and retry. 252 if (F1AtEnd && isNumberChar(F1P[-1])) --F1P; 253 if (F2AtEnd && isNumberChar(F2P[-1])) --F2P; 254 F1P = BackupNumber(F1P, File1Start); 255 F2P = BackupNumber(F2P, File2Start); 256 257 // Now that we are at the start of the numbers, compare them, exiting if 258 // they don't match. 259 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) 260 CompareFailed = true; 261 262 // If we found the end, we succeeded. 263 if (F1P < File1End || F2P < File2End) 264 CompareFailed = true; 265 } 266 267 return CompareFailed; 268 } 269 270 void llvm::AtomicFileWriteError::log(raw_ostream &OS) const { 271 OS << "atomic_write_error: "; 272 switch (Error) { 273 case atomic_write_error::failed_to_create_uniq_file: 274 OS << "failed_to_create_uniq_file"; 275 return; 276 case atomic_write_error::output_stream_error: 277 OS << "output_stream_error"; 278 return; 279 case atomic_write_error::failed_to_rename_temp_file: 280 OS << "failed_to_rename_temp_file"; 281 return; 282 } 283 llvm_unreachable("unknown atomic_write_error value in " 284 "failed_to_rename_temp_file::log()"); 285 } 286 287 llvm::Error llvm::writeFileAtomically(StringRef TempPathModel, 288 StringRef FinalPath, StringRef Buffer) { 289 return writeFileAtomically(TempPathModel, FinalPath, 290 [&Buffer](llvm::raw_ostream &OS) { 291 OS.write(Buffer.data(), Buffer.size()); 292 return llvm::Error::success(); 293 }); 294 } 295 296 llvm::Error llvm::writeFileAtomically( 297 StringRef TempPathModel, StringRef FinalPath, 298 std::function<llvm::Error(llvm::raw_ostream &)> Writer) { 299 SmallString<128> GeneratedUniqPath; 300 int TempFD; 301 if (sys::fs::createUniqueFile(TempPathModel, TempFD, GeneratedUniqPath)) { 302 return llvm::make_error<AtomicFileWriteError>( 303 atomic_write_error::failed_to_create_uniq_file); 304 } 305 llvm::FileRemover RemoveTmpFileOnFail(GeneratedUniqPath); 306 307 raw_fd_ostream OS(TempFD, /*shouldClose=*/true); 308 if (llvm::Error Err = Writer(OS)) { 309 return Err; 310 } 311 312 OS.close(); 313 if (OS.has_error()) { 314 OS.clear_error(); 315 return llvm::make_error<AtomicFileWriteError>( 316 atomic_write_error::output_stream_error); 317 } 318 319 if (sys::fs::rename(/*from=*/GeneratedUniqPath, /*to=*/FinalPath)) { 320 return llvm::make_error<AtomicFileWriteError>( 321 atomic_write_error::failed_to_rename_temp_file); 322 } 323 324 RemoveTmpFileOnFail.releaseFile(); 325 return Error::success(); 326 } 327 328 Expected<FilePermissionsApplier> 329 FilePermissionsApplier::create(StringRef InputFilename) { 330 sys::fs::file_status Status; 331 332 if (InputFilename != "-") { 333 if (auto EC = sys::fs::status(InputFilename, Status)) 334 return createFileError(InputFilename, EC); 335 } else { 336 Status.permissions(static_cast<sys::fs::perms>(0777)); 337 } 338 339 return FilePermissionsApplier(InputFilename, Status); 340 } 341 342 Error FilePermissionsApplier::apply( 343 StringRef OutputFilename, bool CopyDates, 344 std::optional<sys::fs::perms> OverwritePermissions) { 345 sys::fs::file_status Status = InputStatus; 346 347 if (OverwritePermissions) 348 Status.permissions(*OverwritePermissions); 349 350 int FD = 0; 351 352 // Writing to stdout should not be treated as an error here, just 353 // do not set access/modification times or permissions. 354 if (OutputFilename == "-") 355 return Error::success(); 356 357 if (std::error_code EC = sys::fs::openFileForWrite(OutputFilename, FD, 358 sys::fs::CD_OpenExisting)) 359 return createFileError(OutputFilename, EC); 360 361 if (CopyDates) 362 if (std::error_code EC = sys::fs::setLastAccessAndModificationTime( 363 FD, Status.getLastAccessedTime(), Status.getLastModificationTime())) 364 return createFileError(OutputFilename, EC); 365 366 sys::fs::file_status OStat; 367 if (std::error_code EC = sys::fs::status(FD, OStat)) 368 return createFileError(OutputFilename, EC); 369 if (OStat.type() == sys::fs::file_type::regular_file) { 370 #ifndef _WIN32 371 // Keep ownership if llvm-objcopy is called under root. 372 if (OutputFilename == InputFilename && OStat.getUser() == 0) 373 sys::fs::changeFileOwnership(FD, Status.getUser(), Status.getGroup()); 374 #endif 375 376 sys::fs::perms Perm = Status.permissions(); 377 if (OutputFilename != InputFilename) 378 Perm = static_cast<sys::fs::perms>(Perm & ~sys::fs::getUmask() & ~06000); 379 #ifdef _WIN32 380 if (std::error_code EC = sys::fs::setPermissions(OutputFilename, Perm)) 381 #else 382 if (std::error_code EC = sys::fs::setPermissions(FD, Perm)) 383 #endif 384 return createFileError(OutputFilename, EC); 385 } 386 387 if (std::error_code EC = sys::Process::SafelyCloseFileDescriptor(FD)) 388 return createFileError(OutputFilename, EC); 389 390 return Error::success(); 391 } 392 393 char llvm::AtomicFileWriteError::ID; 394