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/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibCore/File.h>
#include <LibCore/System.h>
#include <fcntl.h>
#include <unistd.h>
namespace Core {
ErrorOr<NonnullOwnPtr<File>> File::open(StringView filename, OpenMode mode, mode_t permissions)
{
auto file = TRY(adopt_nonnull_own_or_enomem(new (nothrow) File(mode)));
TRY(file->open_path(filename, permissions));
return file;
}
ErrorOr<NonnullOwnPtr<File>> File::adopt_fd(int fd, OpenMode mode, ShouldCloseFileDescriptor should_close_file_descriptor)
{
if (fd < 0) {
return Error::from_errno(EBADF);
}
if (!has_any_flag(mode, OpenMode::ReadWrite)) {
dbgln("Core::File::adopt_fd: Attempting to adopt a file with neither Read nor Write specified in mode");
return Error::from_errno(EINVAL);
}
auto file = TRY(adopt_nonnull_own_or_enomem(new (nothrow) File(mode, should_close_file_descriptor)));
file->m_fd = fd;
return file;
}
ErrorOr<NonnullOwnPtr<File>> File::standard_input()
{
return File::adopt_fd(STDIN_FILENO, OpenMode::Read, ShouldCloseFileDescriptor::No);
}
ErrorOr<NonnullOwnPtr<File>> File::standard_output()
{
return File::adopt_fd(STDOUT_FILENO, OpenMode::Write, ShouldCloseFileDescriptor::No);
}
ErrorOr<NonnullOwnPtr<File>> File::standard_error()
{
return File::adopt_fd(STDERR_FILENO, OpenMode::Write, ShouldCloseFileDescriptor::No);
}
ErrorOr<NonnullOwnPtr<File>> File::open_file_or_standard_stream(StringView filename, OpenMode mode)
{
if (!filename.is_empty() && filename != "-"sv)
return File::open(filename, mode);
switch (mode) {
case OpenMode::Read:
return standard_input();
case OpenMode::Write:
return standard_output();
default:
VERIFY_NOT_REACHED();
}
}
int File::open_mode_to_options(OpenMode mode)
{
int flags = 0;
if (has_flag(mode, OpenMode::ReadWrite)) {
flags |= O_RDWR | O_CREAT;
} else if (has_flag(mode, OpenMode::Read)) {
flags |= O_RDONLY;
} else if (has_flag(mode, OpenMode::Write)) {
flags |= O_WRONLY | O_CREAT;
bool should_truncate = !has_any_flag(mode, OpenMode::Append | OpenMode::MustBeNew);
if (should_truncate)
flags |= O_TRUNC;
}
if (has_flag(mode, OpenMode::Append))
flags |= O_APPEND;
if (has_flag(mode, OpenMode::Truncate))
flags |= O_TRUNC;
if (has_flag(mode, OpenMode::MustBeNew))
flags |= O_EXCL;
if (!has_flag(mode, OpenMode::KeepOnExec))
flags |= O_CLOEXEC;
if (!has_flag(mode, OpenMode::Nonblocking))
flags |= O_NONBLOCK;
return flags;
}
ErrorOr<void> File::open_path(StringView filename, mode_t permissions)
{
VERIFY(m_fd == -1);
auto flags = open_mode_to_options(m_mode);
m_fd = TRY(System::open(filename, flags, permissions));
return {};
}
ErrorOr<Bytes> File::read_some(Bytes buffer)
{
if (!has_flag(m_mode, OpenMode::Read)) {
// NOTE: POSIX says that if the fd is not open for reading, the call
// will return EBADF. Since we already know whether we can or
// can't read the file, let's avoid a syscall.
return Error::from_errno(EBADF);
}
ssize_t nread = TRY(System::read(m_fd, buffer));
m_last_read_was_eof = nread == 0;
return buffer.trim(nread);
}
ErrorOr<ByteBuffer> File::read_until_eof(size_t block_size)
{
// Note: This is used as a heuristic, it's not valid for devices or virtual files.
auto const potential_file_size = TRY(System::fstat(m_fd)).st_size;
return read_until_eof_impl(block_size, potential_file_size);
}
ErrorOr<size_t> File::write_some(ReadonlyBytes buffer)
{
if (!has_flag(m_mode, OpenMode::Write)) {
// NOTE: Same deal as Read.
return Error::from_errno(EBADF);
}
return TRY(System::write(m_fd, buffer));
}
bool File::is_eof() const { return m_last_read_was_eof; }
bool File::is_open() const { return m_fd >= 0; }
void File::close()
{
if (!is_open()) {
return;
}
// NOTE: The closing of the file can be interrupted by a signal, in which
// case EINTR will be returned by the close syscall. So let's try closing
// the file until we aren't interrupted by rude signals. :^)
ErrorOr<void> result;
do {
result = System::close(m_fd);
} while (result.is_error() && result.error().code() == EINTR);
VERIFY(!result.is_error());
m_fd = -1;
}
ErrorOr<size_t> File::seek(i64 offset, SeekMode mode)
{
int syscall_mode;
switch (mode) {
case SeekMode::SetPosition:
syscall_mode = SEEK_SET;
break;
case SeekMode::FromCurrentPosition:
syscall_mode = SEEK_CUR;
break;
case SeekMode::FromEndPosition:
syscall_mode = SEEK_END;
break;
default:
VERIFY_NOT_REACHED();
}
size_t seek_result = TRY(System::lseek(m_fd, offset, syscall_mode));
m_last_read_was_eof = false;
return seek_result;
}
ErrorOr<void> File::truncate(size_t length)
{
if (length > static_cast<size_t>(NumericLimits<off_t>::max()))
return Error::from_string_literal("Length is larger than the maximum supported length");
return System::ftruncate(m_fd, length);
}
}
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