ns_linux Namespace Reference

Linux-specific system operations. More...

Functions
bool	poll_with_timeout (int fd, short events, std::chrono::milliseconds const &timeout)
	Waits for a file descriptor to be ready for I/O with a timeout.
template<typename Data>
ssize_t	read_with_timeout (int fd, std::chrono::milliseconds const &timeout, std::span< Data > buf)
	Reads from the file descriptor with a timeout.
template<typename Data>
ssize_t	write_with_timeout (int fd, std::chrono::milliseconds const &timeout, std::span< Data > buf)
	Writes to the file descriptor with a timeout.
int	open_with_timeout (fs::path const &path_file_src, std::chrono::milliseconds timeout, int oflag)
	Opens a given file with a timeout.
template<typename Data>
ssize_t	open_read_with_timeout (fs::path const &path_file_src, std::chrono::milliseconds const &timeout, std::span< Data > buf)
	Opens and reads from the given input file.
template<typename Data>
ssize_t	open_write_with_timeout (fs::path const &path_file_src, std::chrono::milliseconds const &timeout, std::span< Data > buf)
	Opens and writes to the given input file.
Value< bool >	module_check (std::string_view str_name)
	Checks if the linux kernel has a module loaded that matches the input name.

Detailed Description

Linux-specific system operations.

Provides Linux kernel-specific functionality including kernel module availability checking, system capability detection, and OS-level feature queries. Used to verify FUSE module availability and other kernel features required by FlatImage.

Function Documentation

module_check()

Value< bool > ns_linux::module_check ( std::string_view str_name )

inlinenodiscard

Checks if the linux kernel has a module loaded that matches the input name.

Parameters

str_name

Name of the module to check for

Returns

Value<bool> The boolean result, or the respective internal error

Definition at line 243 of file linux.hpp.

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open_read_with_timeout()

template<typename Data>

ssize_t ns_linux::open_read_with_timeout ( fs::path const & path_file_src, std::chrono::milliseconds const & timeout, std::span< Data > buf )

inlinenodiscard

Opens and reads from the given input file.

Template Parameters

Data	Type of data elements in the buffer

Parameters

path_file_src	Path to the file to open and read
timeout	The timeout in std::chrono::milliseconds
buf	The buffer in which to store the read data

Returns

ssize_t The number of bytes read or -1 on error. On error, errno is set appropriately (ETIMEDOUT if timeout expires, or standard open()/read() error codes).

Definition at line 205 of file linux.hpp.

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open_with_timeout()

int ns_linux::open_with_timeout ( fs::path const & path_file_src, std::chrono::milliseconds timeout, int oflag )

inlinenodiscard

Opens a given file with a timeout.

Parameters

path_file_src	Path for the file to open
timeout	The timeout in std::chrono::milliseconds
oflag	The open flags O_*

Returns

int The file descriptor or -1 on error. On error, errno is set appropriately (ETIMEDOUT on timeout).

Note

Thread-safe implementation using O_NONBLOCK and retry logic. For FIFOs: Opens with O_NONBLOCK. For writes (O_WRONLY), retries until reader connects or timeout. For reads (O_RDONLY), succeeds immediately but may not have a writer yet. This approach is simpler than pthread_cancel and avoids blocking syscalls entirely. For regular files: opens normally without timeout.

Definition at line 143 of file linux.hpp.

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open_write_with_timeout()

template<typename Data>

ssize_t ns_linux::open_write_with_timeout ( fs::path const & path_file_src, std::chrono::milliseconds const & timeout, std::span< Data > buf )

inlinenodiscard

Opens and writes to the given input file.

Template Parameters

Data	Type of data elements in the buffer

Parameters

path_file_src	Path to the file to open and write
timeout	The timeout in std::chrono::milliseconds
buf	The buffer with the data to write

Returns

ssize_t The number of bytes written or -1 on error. On error, errno is set appropriately (ETIMEDOUT if timeout expires, or standard open()/write() error codes).

Definition at line 226 of file linux.hpp.

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poll_with_timeout()

bool ns_linux::poll_with_timeout ( int fd, short events, std::chrono::milliseconds const & timeout )

inlinenodiscard

Waits for a file descriptor to be ready for I/O with a timeout.

Parameters

fd	The file descriptor to poll
events	Poll events (POLLIN for read, POLLOUT for write)
timeout	The timeout in std::chrono::milliseconds

Returns

bool True if ready, false on timeout or error (errno set appropriately)

Definition at line 53 of file linux.hpp.

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read_with_timeout()

template<typename Data>

ssize_t ns_linux::read_with_timeout ( int fd, std::chrono::milliseconds const & timeout, std::span< Data > buf )

inlinenodiscard

Reads from the file descriptor with a timeout.

Template Parameters

Data	Type of data elements in the buffer

Parameters

fd	The file descriptor
timeout	The timeout in std::chrono::milliseconds
buf	The buffer in which to store the read data

Returns

ssize_t The number of read bytes or -1 on error. On error, errno is set appropriately (ETIMEDOUT if timeout expires, or standard read() error codes).

Note

If timeout expires, returns -1 with errno = ETIMEDOUT. Thread-safe using poll().

Definition at line 89 of file linux.hpp.

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write_with_timeout()

template<typename Data>

ssize_t ns_linux::write_with_timeout ( int fd, std::chrono::milliseconds const & timeout, std::span< Data > buf )

inlinenodiscard

Writes to the file descriptor with a timeout.

Template Parameters

Data	Type of data elements in the buffer

Parameters

fd	The file descriptor
timeout	The timeout in std::chrono::milliseconds
buf	The buffer with the data to write

Returns

ssize_t The number of written bytes or -1 on error. On error, errno is set appropriately (ETIMEDOUT if timeout expires, or standard write() error codes).

Note

If timeout expires, returns -1 with errno = ETIMEDOUT. Thread-safe using poll().

Definition at line 115 of file linux.hpp.

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