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/*
* Copyright © 2015, 2020 Christian Persch
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once
#include <cassert>
#include <cerrno>
#include <memory>
#include <unistd.h>
#include <fcntl.h>
namespace vte::libc {
class ErrnoSaver {
public:
ErrnoSaver() noexcept : m_errsv{errno} { }
~ErrnoSaver() noexcept { errno = m_errsv; }
ErrnoSaver(ErrnoSaver const&) = delete;
ErrnoSaver(ErrnoSaver&&) = delete;
ErrnoSaver& operator=(ErrnoSaver const&) = delete;
ErrnoSaver& operator=(ErrnoSaver&&) = delete;
inline constexpr operator int () const noexcept { return m_errsv; }
inline void reset() noexcept { m_errsv = 0; }
private:
int m_errsv;
}; // class ErrnoSaver
class FD {
public:
constexpr FD() noexcept = default;
explicit constexpr FD(int fd) noexcept : m_fd{fd} { } // adopts the FD
constexpr FD(FD const&) = delete;
constexpr FD(FD&& rhs) noexcept : m_fd{rhs.release()} { }
~FD() noexcept { reset(); }
// adopt the file descriptor
FD& operator=(int rhs) noexcept
{
reset();
m_fd = rhs;
return *this;
}
FD& operator=(FD& rhs) = delete;
FD& operator=(FD&& rhs) noexcept
{
if (this != std::addressof(rhs)) {
reset();
m_fd = rhs.release();
}
return *this;
}
explicit constexpr operator bool() const noexcept { return m_fd != -1; }
constexpr int get() const noexcept { return m_fd; }
constexpr int release() noexcept
{
auto fd = m_fd;
m_fd = -1;
return fd;
}
void reset()
{
if (m_fd != -1) {
auto errsv = ErrnoSaver{};
close(m_fd);
m_fd = -1;
}
}
/* C++20 constexpr */ void swap(FD& other)
{
using std::swap;
swap(m_fd, other.m_fd);
}
private:
int m_fd{-1};
}; // class FD
constexpr bool operator==(FD const& lhs, FD const& rhs) noexcept { return lhs.get() == rhs.get(); }
constexpr bool operator==(FD const& lhs, int rhs) noexcept { return lhs.get() == rhs; }
constexpr bool operator!=(FD const& lhs, FD const& rhs) noexcept { return !(lhs == rhs); }
constexpr bool operator!=(FD const& lhs, int rhs) noexcept { return !(lhs == rhs); }
/* C++20 constexpr */ inline void swap(FD& lhs, FD& rhs) noexcept { lhs.swap(rhs); }
/* FD convenience functions */
static inline int
fd_get_descriptor_flags(int fd)
{
auto flags = int{};
do {
flags = fcntl(fd, F_GETFD);
} while (flags == -1 && errno == EINTR);
return flags;
}
static inline int
fd_set_descriptor_flags(int fd,
int flags)
{
auto r = int{};
do {
r = fcntl(fd, F_SETFD, flags);
} while (r == -1 && errno == EINTR);
return r;
}
static inline int
fd_change_descriptor_flags(int fd,
int set_flags,
int unset_flags)
{
auto const flags = fd_get_descriptor_flags(fd);
if (flags == -1)
return -1;
auto const new_flags = (flags | set_flags) & ~unset_flags;
if (new_flags == flags)
return 0;
return fd_set_descriptor_flags(fd, new_flags);
}
static inline int
fd_get_status_flags(int fd)
{
auto flags = int{};
do {
flags = fcntl(fd, F_GETFL, 0);
} while (flags == -1 && errno == EINTR);
return flags;
}
static inline int
fd_set_status_flags(int fd,
int flags)
{
auto r = int{};
do {
r = fcntl(fd, F_SETFL, flags);
} while (r == -1 && errno == EINTR);
return r;
}
static inline int
fd_change_status_flags(int fd,
int set_flags,
int unset_flags)
{
auto const flags = fd_get_status_flags(fd);
if (flags == -1)
return -1;
auto const new_flags = (flags | set_flags) & ~unset_flags;
if (new_flags == flags)
return 0;
return fd_set_status_flags(fd, new_flags);
}
static inline bool
fd_get_cloexec(int fd)
{
auto const r = fd_get_descriptor_flags(fd);
return r != -1 && (r & FD_CLOEXEC) != 0;
}
static inline int
fd_set_cloexec(int fd)
{
return fd_change_descriptor_flags(fd, FD_CLOEXEC, 0);
}
static inline int
fd_unset_cloexec(int fd)
{
return fd_change_descriptor_flags(fd, 0, FD_CLOEXEC);
}
static inline int
fd_set_nonblock(int fd)
{
return fd_change_status_flags(fd, O_NONBLOCK, 0);
}
static inline int
fd_dup_cloexec(int oldfd,
int newfd)
{
auto r = int{};
do {
r = fcntl(oldfd, F_DUPFD_CLOEXEC, newfd);
} while (r == -1 && errno == EINTR);
return r;
}
static inline int
fd_dup2(int oldfd,
int newfd)
{
auto r = int{};
do {
r = dup2(oldfd, newfd);
} while (r == -1 && errno == EINTR);
return r;
}
} // namespace vte::libc
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