File.cpp

//===-- File.cpp ------------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lldb/Host/File.h"

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>

#ifdef _WIN32
#include "lldb/Host/windows/windows.h"
#else
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <termios.h>
#endif

#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Process.h" // for llvm::sys::Process::FileDescriptorHasColors()

#include "lldb/Host/Config.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/FileSpec.h"
#include "lldb/Utility/Log.h"

using namespace lldb;
using namespace lldb_private;

static const char *GetStreamOpenModeFromOptions(uint32_t options) {
  if (options & File::eOpenOptionAppend) {
    if (options & File::eOpenOptionRead) {
      if (options & File::eOpenOptionCanCreateNewOnly)
        return "a+x";
      else
        return "a+";
    } else if (options & File::eOpenOptionWrite) {
      if (options & File::eOpenOptionCanCreateNewOnly)
        return "ax";
      else
        return "a";
    }
  } else if (options & File::eOpenOptionRead &&
             options & File::eOpenOptionWrite) {
    if (options & File::eOpenOptionCanCreate) {
      if (options & File::eOpenOptionCanCreateNewOnly)
        return "w+x";
      else
        return "w+";
    } else
      return "r+";
  } else if (options & File::eOpenOptionRead) {
    return "r";
  } else if (options & File::eOpenOptionWrite) {
    return "w";
  }
  return NULL;
}

int File::kInvalidDescriptor = -1;
FILE *File::kInvalidStream = NULL;

File::File(const char *path, uint32_t options, uint32_t permissions)
    : IOObject(eFDTypeFile, false), m_descriptor(kInvalidDescriptor),
      m_stream(kInvalidStream), m_options(), m_own_stream(false),
      m_is_interactive(eLazyBoolCalculate),
      m_is_real_terminal(eLazyBoolCalculate) {
  Open(path, options, permissions);
}

File::File(const FileSpec &filespec, uint32_t options, uint32_t permissions)
    : IOObject(eFDTypeFile, false), m_descriptor(kInvalidDescriptor),
      m_stream(kInvalidStream), m_options(0), m_own_stream(false),
      m_is_interactive(eLazyBoolCalculate),
      m_is_real_terminal(eLazyBoolCalculate)

{
  if (filespec) {
    Open(filespec.GetPath().c_str(), options, permissions);
  }
}

File::~File() { Close(); }

int File::GetDescriptor() const {
  if (DescriptorIsValid())
    return m_descriptor;

  // Don't open the file descriptor if we don't need to, just get it from the
  // stream if we have one.
  if (StreamIsValid()) {
#if defined(LLVM_ON_WIN32)
    return _fileno(m_stream);
#else
    return fileno(m_stream);
#endif
  }

  // Invalid descriptor and invalid stream, return invalid descriptor.
  return kInvalidDescriptor;
}

IOObject::WaitableHandle File::GetWaitableHandle() { return m_descriptor; }

void File::SetDescriptor(int fd, bool transfer_ownership) {
  if (IsValid())
    Close();
  m_descriptor = fd;
  m_should_close_fd = transfer_ownership;
}

FILE *File::GetStream() {
  if (!StreamIsValid()) {
    if (DescriptorIsValid()) {
      const char *mode = GetStreamOpenModeFromOptions(m_options);
      if (mode) {
        if (!m_should_close_fd) {
// We must duplicate the file descriptor if we don't own it because
// when you call fdopen, the stream will own the fd
#ifdef _WIN32
          m_descriptor = ::_dup(GetDescriptor());
#else
          m_descriptor = dup(GetDescriptor());
#endif
          m_should_close_fd = true;
        }

        do {
          m_stream = ::fdopen(m_descriptor, mode);
        } while (m_stream == NULL && errno == EINTR);

        // If we got a stream, then we own the stream and should no
        // longer own the descriptor because fclose() will close it for us

        if (m_stream) {
          m_own_stream = true;
          m_should_close_fd = false;
        }
      }
    }
  }
  return m_stream;
}

void File::SetStream(FILE *fh, bool transfer_ownership) {
  if (IsValid())
    Close();
  m_stream = fh;
  m_own_stream = transfer_ownership;
}

Error File::Open(const char *path, uint32_t options, uint32_t permissions) {
  Error error;
  if (IsValid())
    Close();

  int oflag = 0;
  const bool read = options & eOpenOptionRead;
  const bool write = options & eOpenOptionWrite;
  if (write) {
    if (read)
      oflag |= O_RDWR;
    else
      oflag |= O_WRONLY;

    if (options & eOpenOptionAppend)
      oflag |= O_APPEND;

    if (options & eOpenOptionTruncate)
      oflag |= O_TRUNC;

    if (options & eOpenOptionCanCreate)
      oflag |= O_CREAT;

    if (options & eOpenOptionCanCreateNewOnly)
      oflag |= O_CREAT | O_EXCL;
  } else if (read) {
    oflag |= O_RDONLY;

#ifndef _WIN32
    if (options & eOpenOptionDontFollowSymlinks)
      oflag |= O_NOFOLLOW;
#endif
  }

#ifndef _WIN32
  if (options & eOpenOptionNonBlocking)
    oflag |= O_NONBLOCK;
  if (options & eOpenOptionCloseOnExec)
    oflag |= O_CLOEXEC;
#else
  oflag |= O_BINARY;
#endif

  mode_t mode = 0;
  if (oflag & O_CREAT) {
    if (permissions & lldb::eFilePermissionsUserRead)
      mode |= S_IRUSR;
    if (permissions & lldb::eFilePermissionsUserWrite)
      mode |= S_IWUSR;
    if (permissions & lldb::eFilePermissionsUserExecute)
      mode |= S_IXUSR;
    if (permissions & lldb::eFilePermissionsGroupRead)
      mode |= S_IRGRP;
    if (permissions & lldb::eFilePermissionsGroupWrite)
      mode |= S_IWGRP;
    if (permissions & lldb::eFilePermissionsGroupExecute)
      mode |= S_IXGRP;
    if (permissions & lldb::eFilePermissionsWorldRead)
      mode |= S_IROTH;
    if (permissions & lldb::eFilePermissionsWorldWrite)
      mode |= S_IWOTH;
    if (permissions & lldb::eFilePermissionsWorldExecute)
      mode |= S_IXOTH;
  }

  do {
#ifdef _MSC_VER
    std::wstring wpath;
    if (!llvm::ConvertUTF8toWide(path, wpath)) {
      m_descriptor = -1;
      error.SetErrorString("Error converting path to UTF-16");
      return error;
    }
    ::_wsopen_s(&m_descriptor, wpath.c_str(), oflag, _SH_DENYNO, mode);
#else
    m_descriptor = ::open(path, oflag, mode);
#endif
  } while (m_descriptor < 0 && errno == EINTR);

  if (!DescriptorIsValid())
    error.SetErrorToErrno();
  else {
    m_should_close_fd = true;
    m_options = options;
  }

  return error;
}

uint32_t File::GetPermissions(const FileSpec &file_spec, Error &error) {
  if (file_spec) {
    error.Clear();
    auto Perms = llvm::sys::fs::getPermissions(file_spec.GetPath());
    if (Perms)
      return *Perms;
    error = Error(Perms.getError());
    return 0;
  } else
    error.SetErrorString("empty file spec");
  return 0;
}

uint32_t File::GetPermissions(Error &error) const {
  int fd = GetDescriptor();
  if (fd != kInvalidDescriptor) {
    struct stat file_stats;
    if (::fstat(fd, &file_stats) == -1)
      error.SetErrorToErrno();
    else {
      error.Clear();
      return file_stats.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO);
    }
  } else {
    error.SetErrorString("invalid file descriptor");
  }
  return 0;
}

Error File::Close() {
  Error error;
  if (StreamIsValid() && m_own_stream) {
    if (::fclose(m_stream) == EOF)
      error.SetErrorToErrno();
  }

  if (DescriptorIsValid() && m_should_close_fd) {
    if (::close(m_descriptor) != 0)
      error.SetErrorToErrno();
  }
  m_descriptor = kInvalidDescriptor;
  m_stream = kInvalidStream;
  m_options = 0;
  m_own_stream = false;
  m_should_close_fd = false;
  m_is_interactive = eLazyBoolCalculate;
  m_is_real_terminal = eLazyBoolCalculate;
  return error;
}

void File::Clear() {
  m_stream = nullptr;
  m_descriptor = -1;
  m_options = 0;
  m_own_stream = false;
  m_is_interactive = m_supports_colors = m_is_real_terminal =
      eLazyBoolCalculate;
}

Error File::GetFileSpec(FileSpec &file_spec) const {
  Error error;
#ifdef F_GETPATH
  if (IsValid()) {
    char path[PATH_MAX];
    if (::fcntl(GetDescriptor(), F_GETPATH, path) == -1)
      error.SetErrorToErrno();
    else
      file_spec.SetFile(path, false);
  } else {
    error.SetErrorString("invalid file handle");
  }
#elif defined(__linux__)
  char proc[64];
  char path[PATH_MAX];
  if (::snprintf(proc, sizeof(proc), "/proc/self/fd/%d", GetDescriptor()) < 0)
    error.SetErrorString("cannot resolve file descriptor");
  else {
    ssize_t len;
    if ((len = ::readlink(proc, path, sizeof(path) - 1)) == -1)
      error.SetErrorToErrno();
    else {
      path[len] = '\0';
      file_spec.SetFile(path, false);
    }
  }
#else
  error.SetErrorString("File::GetFileSpec is not supported on this platform");
#endif

  if (error.Fail())
    file_spec.Clear();
  return error;
}

off_t File::SeekFromStart(off_t offset, Error *error_ptr) {
  off_t result = 0;
  if (DescriptorIsValid()) {
    result = ::lseek(m_descriptor, offset, SEEK_SET);

    if (error_ptr) {
      if (result == -1)
        error_ptr->SetErrorToErrno();
      else
        error_ptr->Clear();
    }
  } else if (StreamIsValid()) {
    result = ::fseek(m_stream, offset, SEEK_SET);

    if (error_ptr) {
      if (result == -1)
        error_ptr->SetErrorToErrno();
      else
        error_ptr->Clear();
    }
  } else if (error_ptr) {
    error_ptr->SetErrorString("invalid file handle");
  }
  return result;
}

off_t File::SeekFromCurrent(off_t offset, Error *error_ptr) {
  off_t result = -1;
  if (DescriptorIsValid()) {
    result = ::lseek(m_descriptor, offset, SEEK_CUR);

    if (error_ptr) {
      if (result == -1)
        error_ptr->SetErrorToErrno();
      else
        error_ptr->Clear();
    }
  } else if (StreamIsValid()) {
    result = ::fseek(m_stream, offset, SEEK_CUR);

    if (error_ptr) {
      if (result == -1)
        error_ptr->SetErrorToErrno();
      else
        error_ptr->Clear();
    }
  } else if (error_ptr) {
    error_ptr->SetErrorString("invalid file handle");
  }
  return result;
}

off_t File::SeekFromEnd(off_t offset, Error *error_ptr) {
  off_t result = -1;
  if (DescriptorIsValid()) {
    result = ::lseek(m_descriptor, offset, SEEK_END);

    if (error_ptr) {
      if (result == -1)
        error_ptr->SetErrorToErrno();
      else
        error_ptr->Clear();
    }
  } else if (StreamIsValid()) {
    result = ::fseek(m_stream, offset, SEEK_END);

    if (error_ptr) {
      if (result == -1)
        error_ptr->SetErrorToErrno();
      else
        error_ptr->Clear();
    }
  } else if (error_ptr) {
    error_ptr->SetErrorString("invalid file handle");
  }
  return result;
}

Error File::Flush() {
  Error error;
  if (StreamIsValid()) {
    int err = 0;
    do {
      err = ::fflush(m_stream);
    } while (err == EOF && errno == EINTR);

    if (err == EOF)
      error.SetErrorToErrno();
  } else if (!DescriptorIsValid()) {
    error.SetErrorString("invalid file handle");
  }
  return error;
}

Error File::Sync() {
  Error error;
  if (DescriptorIsValid()) {
#ifdef _WIN32
    int err = FlushFileBuffers((HANDLE)_get_osfhandle(m_descriptor));
    if (err == 0)
      error.SetErrorToGenericError();
#else
    int err = 0;
    do {
      err = ::fsync(m_descriptor);
    } while (err == -1 && errno == EINTR);

    if (err == -1)
      error.SetErrorToErrno();
#endif
  } else {
    error.SetErrorString("invalid file handle");
  }
  return error;
}

#if defined(__APPLE__)
// Darwin kernels only can read/write <= INT_MAX bytes
#define MAX_READ_SIZE INT_MAX
#define MAX_WRITE_SIZE INT_MAX
#endif

Error File::Read(void *buf, size_t &num_bytes) {
  Error error;

#if defined(MAX_READ_SIZE)
  if (num_bytes > MAX_READ_SIZE) {
    uint8_t *p = (uint8_t *)buf;
    size_t bytes_left = num_bytes;
    // Init the num_bytes read to zero
    num_bytes = 0;

    while (bytes_left > 0) {
      size_t curr_num_bytes;
      if (bytes_left > MAX_READ_SIZE)
        curr_num_bytes = MAX_READ_SIZE;
      else
        curr_num_bytes = bytes_left;

      error = Read(p + num_bytes, curr_num_bytes);

      // Update how many bytes were read
      num_bytes += curr_num_bytes;
      if (bytes_left < curr_num_bytes)
        bytes_left = 0;
      else
        bytes_left -= curr_num_bytes;

      if (error.Fail())
        break;
    }
    return error;
  }
#endif

  ssize_t bytes_read = -1;
  if (DescriptorIsValid()) {
    do {
      bytes_read = ::read(m_descriptor, buf, num_bytes);
    } while (bytes_read < 0 && errno == EINTR);

    if (bytes_read == -1) {
      error.SetErrorToErrno();
      num_bytes = 0;
    } else
      num_bytes = bytes_read;
  } else if (StreamIsValid()) {
    bytes_read = ::fread(buf, 1, num_bytes, m_stream);

    if (bytes_read == 0) {
      if (::feof(m_stream))
        error.SetErrorString("feof");
      else if (::ferror(m_stream))
        error.SetErrorString("ferror");
      num_bytes = 0;
    } else
      num_bytes = bytes_read;
  } else {
    num_bytes = 0;
    error.SetErrorString("invalid file handle");
  }
  return error;
}

Error File::Write(const void *buf, size_t &num_bytes) {
  Error error;

#if defined(MAX_WRITE_SIZE)
  if (num_bytes > MAX_WRITE_SIZE) {
    const uint8_t *p = (const uint8_t *)buf;
    size_t bytes_left = num_bytes;
    // Init the num_bytes written to zero
    num_bytes = 0;

    while (bytes_left > 0) {
      size_t curr_num_bytes;
      if (bytes_left > MAX_WRITE_SIZE)
        curr_num_bytes = MAX_WRITE_SIZE;
      else
        curr_num_bytes = bytes_left;

      error = Write(p + num_bytes, curr_num_bytes);

      // Update how many bytes were read
      num_bytes += curr_num_bytes;
      if (bytes_left < curr_num_bytes)
        bytes_left = 0;
      else
        bytes_left -= curr_num_bytes;

      if (error.Fail())
        break;
    }
    return error;
  }
#endif

  ssize_t bytes_written = -1;
  if (DescriptorIsValid()) {
    do {
      bytes_written = ::write(m_descriptor, buf, num_bytes);
    } while (bytes_written < 0 && errno == EINTR);

    if (bytes_written == -1) {
      error.SetErrorToErrno();
      num_bytes = 0;
    } else
      num_bytes = bytes_written;
  } else if (StreamIsValid()) {
    bytes_written = ::fwrite(buf, 1, num_bytes, m_stream);

    if (bytes_written == 0) {
      if (::feof(m_stream))
        error.SetErrorString("feof");
      else if (::ferror(m_stream))
        error.SetErrorString("ferror");
      num_bytes = 0;
    } else
      num_bytes = bytes_written;

  } else {
    num_bytes = 0;
    error.SetErrorString("invalid file handle");
  }

  return error;
}

Error File::Read(void *buf, size_t &num_bytes, off_t &offset) {
  Error error;

#if defined(MAX_READ_SIZE)
  if (num_bytes > MAX_READ_SIZE) {
    uint8_t *p = (uint8_t *)buf;
    size_t bytes_left = num_bytes;
    // Init the num_bytes read to zero
    num_bytes = 0;

    while (bytes_left > 0) {
      size_t curr_num_bytes;
      if (bytes_left > MAX_READ_SIZE)
        curr_num_bytes = MAX_READ_SIZE;
      else
        curr_num_bytes = bytes_left;

      error = Read(p + num_bytes, curr_num_bytes, offset);

      // Update how many bytes were read
      num_bytes += curr_num_bytes;
      if (bytes_left < curr_num_bytes)
        bytes_left = 0;
      else
        bytes_left -= curr_num_bytes;

      if (error.Fail())
        break;
    }
    return error;
  }
#endif

#ifndef _WIN32
  int fd = GetDescriptor();
  if (fd != kInvalidDescriptor) {
    ssize_t bytes_read = -1;
    do {
      bytes_read = ::pread(fd, buf, num_bytes, offset);
    } while (bytes_read < 0 && errno == EINTR);

    if (bytes_read < 0) {
      num_bytes = 0;
      error.SetErrorToErrno();
    } else {
      offset += bytes_read;
      num_bytes = bytes_read;
    }
  } else {
    num_bytes = 0;
    error.SetErrorString("invalid file handle");
  }
#else
  long cur = ::lseek(m_descriptor, 0, SEEK_CUR);
  SeekFromStart(offset);
  error = Read(buf, num_bytes);
  if (!error.Fail())
    SeekFromStart(cur);
#endif
  return error;
}

Error File::Read(size_t &num_bytes, off_t &offset, bool null_terminate,
                 DataBufferSP &data_buffer_sp) {
  Error error;

  if (num_bytes > 0) {
    int fd = GetDescriptor();
    if (fd != kInvalidDescriptor) {
      struct stat file_stats;
      if (::fstat(fd, &file_stats) == 0) {
        if (file_stats.st_size > offset) {
          const size_t bytes_left = file_stats.st_size - offset;
          if (num_bytes > bytes_left)
            num_bytes = bytes_left;

          size_t num_bytes_plus_nul_char = num_bytes + (null_terminate ? 1 : 0);
          std::unique_ptr<DataBufferHeap> data_heap_ap;
          data_heap_ap.reset(new DataBufferHeap());
          data_heap_ap->SetByteSize(num_bytes_plus_nul_char);

          if (data_heap_ap.get()) {
            error = Read(data_heap_ap->GetBytes(), num_bytes, offset);
            if (error.Success()) {
              // Make sure we read exactly what we asked for and if we got
              // less, adjust the array
              if (num_bytes_plus_nul_char < data_heap_ap->GetByteSize())
                data_heap_ap->SetByteSize(num_bytes_plus_nul_char);
              data_buffer_sp.reset(data_heap_ap.release());
              return error;
            }
          }
        } else
          error.SetErrorString("file is empty");
      } else
        error.SetErrorToErrno();
    } else
      error.SetErrorString("invalid file handle");
  } else
    error.SetErrorString("invalid file handle");

  num_bytes = 0;
  data_buffer_sp.reset();
  return error;
}

Error File::Write(const void *buf, size_t &num_bytes, off_t &offset) {
  Error error;

#if defined(MAX_WRITE_SIZE)
  if (num_bytes > MAX_WRITE_SIZE) {
    const uint8_t *p = (const uint8_t *)buf;
    size_t bytes_left = num_bytes;
    // Init the num_bytes written to zero
    num_bytes = 0;

    while (bytes_left > 0) {
      size_t curr_num_bytes;
      if (bytes_left > MAX_WRITE_SIZE)
        curr_num_bytes = MAX_WRITE_SIZE;
      else
        curr_num_bytes = bytes_left;

      error = Write(p + num_bytes, curr_num_bytes, offset);

      // Update how many bytes were read
      num_bytes += curr_num_bytes;
      if (bytes_left < curr_num_bytes)
        bytes_left = 0;
      else
        bytes_left -= curr_num_bytes;

      if (error.Fail())
        break;
    }
    return error;
  }
#endif

  int fd = GetDescriptor();
  if (fd != kInvalidDescriptor) {
#ifndef _WIN32
    ssize_t bytes_written = -1;
    do {
      bytes_written = ::pwrite(m_descriptor, buf, num_bytes, offset);
    } while (bytes_written < 0 && errno == EINTR);

    if (bytes_written < 0) {
      num_bytes = 0;
      error.SetErrorToErrno();
    } else {
      offset += bytes_written;
      num_bytes = bytes_written;
    }
#else
    long cur = ::lseek(m_descriptor, 0, SEEK_CUR);
    error = Write(buf, num_bytes);
    long after = ::lseek(m_descriptor, 0, SEEK_CUR);

    if (!error.Fail())
      SeekFromStart(cur);

    offset = after;
#endif
  } else {
    num_bytes = 0;
    error.SetErrorString("invalid file handle");
  }
  return error;
}

//------------------------------------------------------------------
// Print some formatted output to the stream.
//------------------------------------------------------------------
size_t File::Printf(const char *format, ...) {
  va_list args;
  va_start(args, format);
  size_t result = PrintfVarArg(format, args);
  va_end(args);
  return result;
}

//------------------------------------------------------------------
// Print some formatted output to the stream.
//------------------------------------------------------------------
size_t File::PrintfVarArg(const char *format, va_list args) {
  size_t result = 0;
  if (DescriptorIsValid()) {
    char *s = NULL;
    result = vasprintf(&s, format, args);
    if (s != NULL) {
      if (result > 0) {
        size_t s_len = result;
        Write(s, s_len);
        result = s_len;
      }
      free(s);
    }
  } else if (StreamIsValid()) {
    result = ::vfprintf(m_stream, format, args);
  }
  return result;
}

mode_t File::ConvertOpenOptionsForPOSIXOpen(uint32_t open_options) {
  mode_t mode = 0;
  if (open_options & eOpenOptionRead && open_options & eOpenOptionWrite)
    mode |= O_RDWR;
  else if (open_options & eOpenOptionWrite)
    mode |= O_WRONLY;

  if (open_options & eOpenOptionAppend)
    mode |= O_APPEND;

  if (open_options & eOpenOptionTruncate)
    mode |= O_TRUNC;

  if (open_options & eOpenOptionNonBlocking)
    mode |= O_NONBLOCK;

  if (open_options & eOpenOptionCanCreateNewOnly)
    mode |= O_CREAT | O_EXCL;
  else if (open_options & eOpenOptionCanCreate)
    mode |= O_CREAT;

  return mode;
}

void File::CalculateInteractiveAndTerminal() {
  const int fd = GetDescriptor();
  if (fd >= 0) {
    m_is_interactive = eLazyBoolNo;
    m_is_real_terminal = eLazyBoolNo;
#if defined(_WIN32)
    if (_isatty(fd)) {
      m_is_interactive = eLazyBoolYes;
      m_is_real_terminal = eLazyBoolYes;
    }
#else
    if (isatty(fd)) {
      m_is_interactive = eLazyBoolYes;
      struct winsize window_size;
      if (::ioctl(fd, TIOCGWINSZ, &window_size) == 0) {
        if (window_size.ws_col > 0) {
          m_is_real_terminal = eLazyBoolYes;
          if (llvm::sys::Process::FileDescriptorHasColors(fd))
            m_supports_colors = eLazyBoolYes;
        }
      }
    }
#endif
  }
}

bool File::GetIsInteractive() {
  if (m_is_interactive == eLazyBoolCalculate)
    CalculateInteractiveAndTerminal();
  return m_is_interactive == eLazyBoolYes;
}

bool File::GetIsRealTerminal() {
  if (m_is_real_terminal == eLazyBoolCalculate)
    CalculateInteractiveAndTerminal();
  return m_is_real_terminal == eLazyBoolYes;
}

bool File::GetIsTerminalWithColors() {
  if (m_supports_colors == eLazyBoolCalculate)
    CalculateInteractiveAndTerminal();
  return m_supports_colors == eLazyBoolYes;
}