flang/runtime/file.cpp

   1 //===-- runtime/file.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 "file.h"
  10 #include "flang/Runtime/magic-numbers.h"
  11 #include "flang/Runtime/memory.h"
  12 #include <algorithm>
  13 #include <cerrno>
  14 #include <cstring>
  15 #include <fcntl.h>
  16 #include <stdlib.h>
  17 #include <sys/stat.h>
  18 #ifdef _WIN32
  19 #define NOMINMAX
  20 #include <io.h>
  21 #include <windows.h>
  22 #else
  23 #include <unistd.h>
  24 #endif
  25
  26 namespace Fortran::runtime::io {
  27
  28 void OpenFile::set_path(OwningPtr<char> &&path, std::size_t bytes) {
  29   path_ = std::move(path);
  30   pathLength_ = bytes;
  31 }
  32
  33 static int openfile_mkstemp(IoErrorHandler &handler) {
  34 #ifdef _WIN32
  35   const unsigned int uUnique{0};
  36   // GetTempFileNameA needs a directory name < MAX_PATH-14 characters in length.
  37   // https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-gettempfilenamea
  38   char tempDirName[MAX_PATH - 14];
  39   char tempFileName[MAX_PATH];
  40   unsigned long nBufferLength{sizeof(tempDirName)};
  41   nBufferLength = ::GetTempPathA(nBufferLength, tempDirName);
  42   if (nBufferLength > sizeof(tempDirName) || nBufferLength == 0) {
  43     return -1;
  44   }
  45   if (::GetTempFileNameA(tempDirName, "Fortran", uUnique, tempFileName) == 0) {
  46     return -1;
  47   }
  48   int fd{::_open(tempFileName, _O_CREAT | _O_BINARY | _O_TEMPORARY | _O_RDWR,
  49       _S_IREAD | _S_IWRITE)};
  50 #else
  51   char path[]{"/tmp/Fortran-Scratch-XXXXXX"};
  52   int fd{::mkstemp(path)};
  53 #endif
  54   if (fd < 0) {
  55     handler.SignalErrno();
  56   }
  57 #ifndef _WIN32
  58   ::unlink(path);
  59 #endif
  60   return fd;
  61 }
  62
  63 void OpenFile::Open(OpenStatus status, std::optional<Action> action,
  64     Position position, IoErrorHandler &handler) {
  65   if (fd_ >= 0 &&
  66       (status == OpenStatus::Old || status == OpenStatus::Unknown)) {
  67     return;
  68   }
  69   CloseFd(handler);
  70   if (status == OpenStatus::Scratch) {
  71     if (path_.get()) {
  72       handler.SignalError("FILE= must not appear with STATUS='SCRATCH'");
  73       path_.reset();
  74     }
  75     if (!action) {
  76       action = Action::ReadWrite;
  77     }
  78     fd_ = openfile_mkstemp(handler);
  79   } else {
  80     if (!path_.get()) {
  81       handler.SignalError("FILE= is required");
  82       return;
  83     }
  84     int flags{0};
  85 #ifdef _WIN32
  86     // We emit explicit CR+LF line endings and cope with them on input
  87     // for formatted files, since we can't yet always know now at OPEN
  88     // time whether the file is formatted or not.
  89     flags |= O_BINARY;
  90 #endif
  91     if (status != OpenStatus::Old) {
  92       flags |= O_CREAT;
  93     }
  94     if (status == OpenStatus::New) {
  95       flags |= O_EXCL;
  96     } else if (status == OpenStatus::Replace) {
  97       flags |= O_TRUNC;
  98     }
  99     if (!action) {
 100       // Try to open read/write, back off to read-only or even write-only
 101       // on failure
 102       fd_ = ::open(path_.get(), flags | O_RDWR, 0600);
 103       if (fd_ >= 0) {
 104         action = Action::ReadWrite;
 105       } else {
 106         fd_ = ::open(path_.get(), flags | O_RDONLY, 0600);
 107         if (fd_ >= 0) {
 108           action = Action::Read;
 109         } else {
 110           action = Action::Write;
 111         }
 112       }
 113     }
 114     if (fd_ < 0) {
 115       switch (*action) {
 116       case Action::Read:
 117         flags |= O_RDONLY;
 118         break;
 119       case Action::Write:
 120         flags |= O_WRONLY;
 121         break;
 122       case Action::ReadWrite:
 123         flags |= O_RDWR;
 124         break;
 125       }
 126       fd_ = ::open(path_.get(), flags, 0600);
 127       if (fd_ < 0) {
 128         handler.SignalErrno();
 129       }
 130     }
 131   }
 132   RUNTIME_CHECK(handler, action.has_value());
 133   pending_.reset();
 134   if (position == Position::Append && !RawSeekToEnd()) {
 135     handler.SignalError(IostatOpenBadAppend);
 136   }
 137   isTerminal_ = IsATerminal(fd_) == 1;
 138   mayRead_ = *action != Action::Write;
 139   mayWrite_ = *action != Action::Read;
 140   if (status == OpenStatus::Old || status == OpenStatus::Unknown) {
 141     knownSize_.reset();
 142 #ifndef _WIN32
 143     struct stat buf;
 144     if (::fstat(fd_, &buf) == 0) {
 145       mayPosition_ = S_ISREG(buf.st_mode);
 146       knownSize_ = buf.st_size;
 147     }
 148 #else // TODO: _WIN32
 149     mayPosition_ = true;
 150 #endif
 151   } else {
 152     knownSize_ = 0;
 153     mayPosition_ = true;
 154   }
 155   openPosition_ = position; // for INQUIRE(POSITION=)
 156 }
 157
 158 void OpenFile::Predefine(int fd) {
 159   fd_ = fd;
 160   path_.reset();
 161   pathLength_ = 0;
 162   position_ = 0;
 163   knownSize_.reset();
 164   nextId_ = 0;
 165   pending_.reset();
 166   isTerminal_ = IsATerminal(fd_) == 1;
 167   mayRead_ = fd == 0;
 168   mayWrite_ = fd != 0;
 169   mayPosition_ = false;
 170 #ifdef _WIN32
 171   isWindowsTextFile_ = true;
 172 #endif
 173 }
 174
 175 void OpenFile::Close(CloseStatus status, IoErrorHandler &handler) {
 176   pending_.reset();
 177   knownSize_.reset();
 178   switch (status) {
 179   case CloseStatus::Keep:
 180     break;
 181   case CloseStatus::Delete:
 182     if (path_.get()) {
 183       ::unlink(path_.get());
 184     }
 185     break;
 186   }
 187   path_.reset();
 188   CloseFd(handler);
 189 }
 190
 191 std::size_t OpenFile::Read(FileOffset at, char *buffer, std::size_t minBytes,
 192     std::size_t maxBytes, IoErrorHandler &handler) {
 193   if (maxBytes == 0) {
 194     return 0;
 195   }
 196   CheckOpen(handler);
 197   if (!Seek(at, handler)) {
 198     return 0;
 199   }
 200   minBytes = std::min(minBytes, maxBytes);
 201   std::size_t got{0};
 202   while (got < minBytes) {
 203     auto chunk{::read(fd_, buffer + got, maxBytes - got)};
 204     if (chunk == 0) {
 205       break;
 206     } else if (chunk < 0) {
 207       auto err{errno};
 208       if (err != EAGAIN && err != EWOULDBLOCK && err != EINTR) {
 209         handler.SignalError(err);
 210         break;
 211       }
 212     } else {
 213       SetPosition(position_ + chunk);
 214       got += chunk;
 215     }
 216   }
 217   return got;
 218 }
 219
 220 std::size_t OpenFile::Write(FileOffset at, const char *buffer,
 221     std::size_t bytes, IoErrorHandler &handler) {
 222   if (bytes == 0) {
 223     return 0;
 224   }
 225   CheckOpen(handler);
 226   if (!Seek(at, handler)) {
 227     return 0;
 228   }
 229   std::size_t put{0};
 230   while (put < bytes) {
 231     auto chunk{::write(fd_, buffer + put, bytes - put)};
 232     if (chunk >= 0) {
 233       SetPosition(position_ + chunk);
 234       put += chunk;
 235     } else {
 236       auto err{errno};
 237       if (err != EAGAIN && err != EWOULDBLOCK && err != EINTR) {
 238         handler.SignalError(err);
 239         break;
 240       }
 241     }
 242   }
 243   if (knownSize_ && position_ > *knownSize_) {
 244     knownSize_ = position_;
 245   }
 246   return put;
 247 }
 248
 249 inline static int openfile_ftruncate(int fd, OpenFile::FileOffset at) {
 250 #ifdef _WIN32
 251   return ::_chsize(fd, at);
 252 #else
 253   return ::ftruncate(fd, at);
 254 #endif
 255 }
 256
 257 void OpenFile::Truncate(FileOffset at, IoErrorHandler &handler) {
 258   CheckOpen(handler);
 259   if (!knownSize_ || *knownSize_ != at) {
 260     if (openfile_ftruncate(fd_, at) != 0) {
 261       handler.SignalErrno();
 262     }
 263     knownSize_ = at;
 264   }
 265 }
 266
 267 // The operation is performed immediately; the results are saved
 268 // to be claimed by a later WAIT statement.
 269 // TODO: True asynchronicity
 270 int OpenFile::ReadAsynchronously(
 271     FileOffset at, char *buffer, std::size_t bytes, IoErrorHandler &handler) {
 272   CheckOpen(handler);
 273   int iostat{0};
 274   for (std::size_t got{0}; got < bytes;) {
 275 #if _XOPEN_SOURCE >= 500 || _POSIX_C_SOURCE >= 200809L
 276     auto chunk{::pread(fd_, buffer + got, bytes - got, at)};
 277 #else
 278     auto chunk{Seek(at, handler) ? ::read(fd_, buffer + got, bytes - got) : -1};
 279 #endif
 280     if (chunk == 0) {
 281       iostat = FORTRAN_RUNTIME_IOSTAT_END;
 282       break;
 283     }
 284     if (chunk < 0) {
 285       auto err{errno};
 286       if (err != EAGAIN && err != EWOULDBLOCK && err != EINTR) {
 287         iostat = err;
 288         break;
 289       }
 290     } else {
 291       at += chunk;
 292       got += chunk;
 293     }
 294   }
 295   return PendingResult(handler, iostat);
 296 }
 297
 298 // TODO: True asynchronicity
 299 int OpenFile::WriteAsynchronously(FileOffset at, const char *buffer,
 300     std::size_t bytes, IoErrorHandler &handler) {
 301   CheckOpen(handler);
 302   int iostat{0};
 303   for (std::size_t put{0}; put < bytes;) {
 304 #if _XOPEN_SOURCE >= 500 || _POSIX_C_SOURCE >= 200809L
 305     auto chunk{::pwrite(fd_, buffer + put, bytes - put, at)};
 306 #else
 307     auto chunk{
 308         Seek(at, handler) ? ::write(fd_, buffer + put, bytes - put) : -1};
 309 #endif
 310     if (chunk >= 0) {
 311       at += chunk;
 312       put += chunk;
 313     } else {
 314       auto err{errno};
 315       if (err != EAGAIN && err != EWOULDBLOCK && err != EINTR) {
 316         iostat = err;
 317         break;
 318       }
 319     }
 320   }
 321   return PendingResult(handler, iostat);
 322 }
 323
 324 void OpenFile::Wait(int id, IoErrorHandler &handler) {
 325   std::optional<int> ioStat;
 326   Pending *prev{nullptr};
 327   for (Pending *p{pending_.get()}; p; p = (prev = p)->next.get()) {
 328     if (p->id == id) {
 329       ioStat = p->ioStat;
 330       if (prev) {
 331         prev->next.reset(p->next.release());
 332       } else {
 333         pending_.reset(p->next.release());
 334       }
 335       break;
 336     }
 337   }
 338   if (ioStat) {
 339     handler.SignalError(*ioStat);
 340   }
 341 }
 342
 343 void OpenFile::WaitAll(IoErrorHandler &handler) {
 344   while (true) {
 345     int ioStat;
 346     if (pending_) {
 347       ioStat = pending_->ioStat;
 348       pending_.reset(pending_->next.release());
 349     } else {
 350       return;
 351     }
 352     handler.SignalError(ioStat);
 353   }
 354 }
 355
 356 Position OpenFile::InquirePosition() const {
 357   if (openPosition_) { // from OPEN statement
 358     return *openPosition_;
 359   } else { // unit has been repositioned since opening
 360     if (position_ == knownSize_.value_or(position_ + 1)) {
 361       return Position::Append;
 362     } else if (position_ == 0 && mayPosition_) {
 363       return Position::Rewind;
 364     } else {
 365       return Position::AsIs; // processor-dependent & no common behavior
 366     }
 367   }
 368 }
 369
 370 void OpenFile::CheckOpen(const Terminator &terminator) {
 371   RUNTIME_CHECK(terminator, fd_ >= 0);
 372 }
 373
 374 bool OpenFile::Seek(FileOffset at, IoErrorHandler &handler) {
 375   if (at == position_) {
 376     return true;
 377   } else if (RawSeek(at)) {
 378     SetPosition(at);
 379     return true;
 380   } else {
 381     handler.SignalError(IostatCannotReposition);
 382     return false;
 383   }
 384 }
 385
 386 bool OpenFile::RawSeek(FileOffset at) {
 387 #ifdef _LARGEFILE64_SOURCE
 388   return ::lseek64(fd_, at, SEEK_SET) == at;
 389 #else
 390   return ::lseek(fd_, at, SEEK_SET) == at;
 391 #endif
 392 }
 393
 394 bool OpenFile::RawSeekToEnd() {
 395 #ifdef _LARGEFILE64_SOURCE
 396   std::int64_t at{::lseek64(fd_, 0, SEEK_END)};
 397 #else
 398   std::int64_t at{::lseek(fd_, 0, SEEK_END)};
 399 #endif
 400   if (at >= 0) {
 401     knownSize_ = at;
 402     return true;
 403   } else {
 404     return false;
 405   }
 406 }
 407
 408 int OpenFile::PendingResult(const Terminator &terminator, int iostat) {
 409   int id{nextId_++};
 410   pending_ = New<Pending>{terminator}(id, iostat, std::move(pending_));
 411   return id;
 412 }
 413
 414 void OpenFile::CloseFd(IoErrorHandler &handler) {
 415   if (fd_ >= 0) {
 416     if (fd_ <= 2) {
 417       // don't actually close a standard file descriptor, we might need it
 418     } else {
 419       if (::close(fd_) != 0) {
 420         handler.SignalErrno();
 421       }
 422     }
 423     fd_ = -1;
 424   }
 425 }
 426
 427 bool IsATerminal(int fd) { return ::isatty(fd); }
 428
 429 #if defined(_WIN32) && !defined(F_OK)
 430 // Access flags are normally defined in unistd.h, which unavailable under
 431 // Windows. Instead, define the flags as documented at
 432 // https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/access-waccess
 433 // On Mingw, io.h does define these same constants - so check whether they
 434 // already are defined before defining these.
 435 #define F_OK 00
 436 #define W_OK 02
 437 #define R_OK 04
 438 #endif
 439
 440 bool IsExtant(const char *path) { return ::access(path, F_OK) == 0; }
 441 bool MayRead(const char *path) { return ::access(path, R_OK) == 0; }
 442 bool MayWrite(const char *path) { return ::access(path, W_OK) == 0; }
 443 bool MayReadAndWrite(const char *path) {
 444   return ::access(path, R_OK | W_OK) == 0;
 445 }
 446
 447 std::int64_t SizeInBytes(const char *path) {
 448 #ifndef _WIN32
 449   struct stat buf;
 450   if (::stat(path, &buf) == 0) {
 451     return buf.st_size;
 452   }
 453 #else // TODO: _WIN32
 454 #endif
 455   // No Fortran compiler signals an error
 456   return -1;
 457 }
 458
 459 } // namespace Fortran::runtime::io