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//===-- File.h --------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef liblldb_File_h_
#define liblldb_File_h_
#include "lldb/Host/PosixApi.h"
#include "lldb/Utility/IOObject.h"
#include "lldb/Utility/Status.h"
#include "lldb/lldb-private.h"
#include "llvm/ADT/BitmaskEnum.h"
#include <mutex>
#include <stdarg.h>
#include <stdio.h>
#include <sys/types.h>
namespace lldb_private {
LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE();
/// \class File File.h "lldb/Host/File.h"
/// An abstract base class for files.
///
/// Files will often be NativeFiles, which provides a wrapper
/// around host OS file functionality. But it
/// is also possible to subclass file to provide objects that have file
/// or stream functionality but are not backed by any host OS file.
class File : public IOObject {
public:
static int kInvalidDescriptor;
static FILE *kInvalidStream;
// NB this enum is used in the lldb platform gdb-remote packet
// vFile:open: and existing values cannot be modified.
//
// FIXME
// These values do not match the values used by GDB
// * https://sourceware.org/gdb/onlinedocs/gdb/Open-Flags.html#Open-Flags
// * rdar://problem/46788934
enum OpenOptions : uint32_t {
eOpenOptionRead = (1u << 0), // Open file for reading
eOpenOptionWrite = (1u << 1), // Open file for writing
eOpenOptionAppend =
(1u << 2), // Don't truncate file when opening, append to end of file
eOpenOptionTruncate = (1u << 3), // Truncate file when opening
eOpenOptionNonBlocking = (1u << 4), // File reads
eOpenOptionCanCreate = (1u << 5), // Create file if doesn't already exist
eOpenOptionCanCreateNewOnly =
(1u << 6), // Can create file only if it doesn't already exist
eOpenOptionDontFollowSymlinks = (1u << 7),
eOpenOptionCloseOnExec =
(1u << 8), // Close the file when executing a new process
LLVM_MARK_AS_BITMASK_ENUM(/* largest_value= */ eOpenOptionCloseOnExec)
};
static mode_t ConvertOpenOptionsForPOSIXOpen(OpenOptions open_options);
static llvm::Expected<OpenOptions> GetOptionsFromMode(llvm::StringRef mode);
static bool DescriptorIsValid(int descriptor) { return descriptor >= 0; };
File()
: IOObject(eFDTypeFile), m_is_interactive(eLazyBoolCalculate),
m_is_real_terminal(eLazyBoolCalculate),
m_supports_colors(eLazyBoolCalculate){};
/// Read bytes from a file from the current file position into buf.
///
/// NOTE: This function is NOT thread safe. Use the read function
/// that takes an "off_t &offset" to ensure correct operation in multi-
/// threaded environments.
///
/// \param[out] buf
///
/// \param[in,out] num_bytes.
/// Pass in the size of buf. Read will pass out the number
/// of bytes read. Zero bytes read with no error indicates
/// EOF.
///
/// \return
/// success, ENOTSUP, or another error.
Status Read(void *buf, size_t &num_bytes) override;
/// Write bytes from buf to a file at the current file position.
///
/// NOTE: This function is NOT thread safe. Use the write function
/// that takes an "off_t &offset" to ensure correct operation in multi-
/// threaded environments.
///
/// \param[in] buf
///
/// \param[in,out] num_bytes
/// Pass in the size of buf. Write will pass out the number
/// of bytes written. Write will attempt write the full number
/// of bytes and will not return early except on error.
///
/// \return
/// success, ENOTSUP, or another error.
Status Write(const void *buf, size_t &num_bytes) override;
/// IsValid
///
/// \return
/// true iff the file is valid.
bool IsValid() const override;
/// Flush any buffers and release any resources owned by the file.
/// After Close() the file will be invalid.
///
/// \return
/// success or an error.
Status Close() override;
/// Get a handle that can be used for OS polling interfaces, such
/// as WaitForMultipleObjects, select, or epoll. This may return
/// IOObject::kInvalidHandleValue if none is available. This will
/// generally be the same as the file descriptor, this function
/// is not interchangeable with GetDescriptor(). A WaitableHandle
/// must only be used for polling, not actual I/O.
///
/// \return
/// a valid handle or IOObject::kInvalidHandleValue
WaitableHandle GetWaitableHandle() override;
/// Get the file specification for this file, if possible.
///
/// \param[out] file_spec
/// the file specification.
/// \return
/// ENOTSUP, success, or another error.
virtual Status GetFileSpec(FileSpec &file_spec) const;
/// DEPRECATED! Extract the underlying FILE* and reset this File without closing it.
///
/// This is only here to support legacy SB interfaces that need to convert scripting
/// language objects into FILE* streams. That conversion is inherently sketchy and
/// doing so may cause the stream to be leaked.
///
/// After calling this the File will be reset to its original state. It will be
/// invalid and it will not hold on to any resources.
///
/// \return
/// The underlying FILE* stream from this File, if one exists and can be extracted,
/// nullptr otherwise.
virtual FILE *TakeStreamAndClear();
/// Get underlying OS file descriptor for this file, or kInvalidDescriptor.
/// If the descriptor is valid, then it may be used directly for I/O
/// However, the File may also perform it's own buffering, so avoid using
/// this if it is not necessary, or use Flush() appropriately.
///
/// \return
/// a valid file descriptor for this file or kInvalidDescriptor
virtual int GetDescriptor() const;
/// Get the underlying libc stream for this file, or NULL.
///
/// Not all valid files will have a FILE* stream. This should only be
/// used if absolutely necessary, such as to interact with 3rd party
/// libraries that need FILE* streams.
///
/// \return
/// a valid stream or NULL;
virtual FILE *GetStream();
/// Seek to an offset relative to the beginning of the file.
///
/// NOTE: This function is NOT thread safe, other threads that
/// access this object might also change the current file position. For
/// thread safe reads and writes see the following functions: @see
/// File::Read (void *, size_t, off_t &) \see File::Write (const void *,
/// size_t, off_t &)
///
/// \param[in] offset
/// The offset to seek to within the file relative to the
/// beginning of the file.
///
/// \param[in] error_ptr
/// A pointer to a lldb_private::Status object that will be
/// filled in if non-nullptr.
///
/// \return
/// The resulting seek offset, or -1 on error.
virtual off_t SeekFromStart(off_t offset, Status *error_ptr = nullptr);
/// Seek to an offset relative to the current file position.
///
/// NOTE: This function is NOT thread safe, other threads that
/// access this object might also change the current file position. For
/// thread safe reads and writes see the following functions: @see
/// File::Read (void *, size_t, off_t &) \see File::Write (const void *,
/// size_t, off_t &)
///
/// \param[in] offset
/// The offset to seek to within the file relative to the
/// current file position.
///
/// \param[in] error_ptr
/// A pointer to a lldb_private::Status object that will be
/// filled in if non-nullptr.
///
/// \return
/// The resulting seek offset, or -1 on error.
virtual off_t SeekFromCurrent(off_t offset, Status *error_ptr = nullptr);
/// Seek to an offset relative to the end of the file.
///
/// NOTE: This function is NOT thread safe, other threads that
/// access this object might also change the current file position. For
/// thread safe reads and writes see the following functions: @see
/// File::Read (void *, size_t, off_t &) \see File::Write (const void *,
/// size_t, off_t &)
///
/// \param[in,out] offset
/// The offset to seek to within the file relative to the
/// end of the file which gets filled in with the resulting
/// absolute file offset.
///
/// \param[in] error_ptr
/// A pointer to a lldb_private::Status object that will be
/// filled in if non-nullptr.
///
/// \return
/// The resulting seek offset, or -1 on error.
virtual off_t SeekFromEnd(off_t offset, Status *error_ptr = nullptr);
/// Read bytes from a file from the specified file offset.
///
/// NOTE: This function is thread safe in that clients manager their
/// own file position markers and reads on other threads won't mess up the
/// current read.
///
/// \param[in] dst
/// A buffer where to put the bytes that are read.
///
/// \param[in,out] num_bytes
/// The number of bytes to read form the current file position
/// which gets modified with the number of bytes that were read.
///
/// \param[in,out] offset
/// The offset within the file from which to read \a num_bytes
/// bytes. This offset gets incremented by the number of bytes
/// that were read.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
virtual Status Read(void *dst, size_t &num_bytes, off_t &offset);
/// Write bytes to a file at the specified file offset.
///
/// NOTE: This function is thread safe in that clients manager their
/// own file position markers, though clients will need to implement their
/// own locking externally to avoid multiple people writing to the file at
/// the same time.
///
/// \param[in] src
/// A buffer containing the bytes to write.
///
/// \param[in,out] num_bytes
/// The number of bytes to write to the file at offset \a offset.
/// \a num_bytes gets modified with the number of bytes that
/// were read.
///
/// \param[in,out] offset
/// The offset within the file at which to write \a num_bytes
/// bytes. This offset gets incremented by the number of bytes
/// that were written.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
virtual Status Write(const void *src, size_t &num_bytes, off_t &offset);
/// Flush the current stream
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
virtual Status Flush();
/// Sync to disk.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
virtual Status Sync();
/// Output printf formatted output to the stream.
///
/// NOTE: this is not virtual, because it just calls the va_list
/// version of the function.
///
/// Print some formatted output to the stream.
///
/// \param[in] format
/// A printf style format string.
///
/// \param[in] ...
/// Variable arguments that are needed for the printf style
/// format string \a format.
size_t Printf(const char *format, ...) __attribute__((format(printf, 2, 3)));
/// Output printf formatted output to the stream.
///
/// Print some formatted output to the stream.
///
/// \param[in] format
/// A printf style format string.
///
/// \param[in] args
/// Variable arguments that are needed for the printf style
/// format string \a format.
virtual size_t PrintfVarArg(const char *format, va_list args);
/// Get the permissions for a this file.
///
/// \return
/// Bits logical OR'ed together from the permission bits defined
/// in lldb_private::File::Permissions.
uint32_t GetPermissions(Status &error) const;
/// Return true if this file is interactive.
///
/// \return
/// True if this file is a terminal (tty or pty), false
/// otherwise.
bool GetIsInteractive();
/// Return true if this file from a real terminal.
///
/// Just knowing a file is a interactive isn't enough, we also need to know
/// if the terminal has a width and height so we can do cursor movement and
/// other terminal manipulations by sending escape sequences.
///
/// \return
/// True if this file is a terminal (tty, not a pty) that has
/// a non-zero width and height, false otherwise.
bool GetIsRealTerminal();
/// Return true if this file is a terminal which supports colors.
///
/// \return
/// True iff this is a terminal and it supports colors.
bool GetIsTerminalWithColors();
operator bool() const { return IsValid(); };
bool operator!() const { return !IsValid(); };
protected:
LazyBool m_is_interactive;
LazyBool m_is_real_terminal;
LazyBool m_supports_colors;
void CalculateInteractiveAndTerminal();
private:
DISALLOW_COPY_AND_ASSIGN(File);
};
class NativeFile : public File {
public:
NativeFile()
: m_descriptor(kInvalidDescriptor), m_own_descriptor(false),
m_stream(kInvalidStream), m_options(), m_own_stream(false) {}
NativeFile(FILE *fh, bool transfer_ownership)
: m_descriptor(kInvalidDescriptor), m_own_descriptor(false), m_stream(fh),
m_options(), m_own_stream(transfer_ownership) {}
NativeFile(int fd, OpenOptions options, bool transfer_ownership)
: m_descriptor(fd), m_own_descriptor(transfer_ownership),
m_stream(kInvalidStream), m_options(options), m_own_stream(false) {}
~NativeFile() override { Close(); }
bool IsValid() const override {
return DescriptorIsValid() || StreamIsValid();
}
Status Read(void *buf, size_t &num_bytes) override;
Status Write(const void *buf, size_t &num_bytes) override;
Status Close() override;
WaitableHandle GetWaitableHandle() override;
Status GetFileSpec(FileSpec &file_spec) const override;
FILE *TakeStreamAndClear() override;
int GetDescriptor() const override;
FILE *GetStream() override;
off_t SeekFromStart(off_t offset, Status *error_ptr = nullptr) override;
off_t SeekFromCurrent(off_t offset, Status *error_ptr = nullptr) override;
off_t SeekFromEnd(off_t offset, Status *error_ptr = nullptr) override;
Status Read(void *dst, size_t &num_bytes, off_t &offset) override;
Status Write(const void *src, size_t &num_bytes, off_t &offset) override;
Status Flush() override;
Status Sync() override;
size_t PrintfVarArg(const char *format, va_list args) override;
protected:
bool DescriptorIsValid() const {
return File::DescriptorIsValid(m_descriptor);
}
bool StreamIsValid() const { return m_stream != kInvalidStream; }
// Member variables
int m_descriptor;
bool m_own_descriptor;
FILE *m_stream;
OpenOptions m_options;
bool m_own_stream;
std::mutex offset_access_mutex;
private:
DISALLOW_COPY_AND_ASSIGN(NativeFile);
};
} // namespace lldb_private
#endif // liblldb_File_h_