unistd.h File Reference

#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
#include "kconfig.h"

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Macros
#define	MQ_PRIO_MAX   _MQ_PRIO_MAX
#define	STDIN_FILENO   0 /* Standard input file descriptor */
#define	STDOUT_FILENO   1 /* Standard output file descriptor */
#define	STDERR_FILENO   2 /* Standard error file descriptor */
#define	_SC_ARG_MAX   0
#define	_SC_CLK_TCK   2
#define	_SC_OPEN_MAX   4
#define	_SC_PAGESIZE   8
#define	sysconf   _sysconf
	Report a value of the system that is decided when it is built. More...
#define	F_OK   0 /* The file exists */
#define	X_OK   1 /* The file can be executed */
#define	W_OK   2 /* The file can be written */
#define	R_OK   4 /* The file can be read */

Functions
unsigned int	sleep (unsigned int seconds)
	To cause the calling thread to sleep either until the number of real-time seconds specified in seconds have elapsed or until a signal arrives which is not ignored. More...
int	usleep (useconds_t usec)
	Suspend execution of the calling thread for a given time in microseconds. More...
int	close (int fd)
	Close a file descriptor, so that it no longer refers to any file and may be reused. More...
int	dup (int oldfd)
	Create a copy of the file descriptor oldfd, using the lowest-numbered unused file descriptor for the new descriptor. More...
int	dup2 (int oldfd, int newfd)
	Perform the same task as dup(), but use the file descriptor number specified by newfd. More...
int	pipe (int pipefd[2])
	Create a pipe, a stream that is written to through one descriptor and read from through the other. More...
pid_t	vfork (void)
	Create a child process. Tenok runs every task from the image it booted and has no way to make another, so the call always fails. More...
pid_t	fork (void)
	Create a child process, the way vfork() does not either. More...
pid_t	setsid (void)
	Start a session. Tenok has the one console and no sessions to give it out to. More...
int	execve (const char *pathname, char *const argv[], char *const envp[])
	Replace the running program with the one the pathname names. No file of Tenok is in a format the system can execute, so the call always fails. More...
int	execvp (const char *file, char *const argv[])
	Replace the running program with the one found by searching PATH for the file, the way execve() does. More...
ssize_t	read (int fd, void *buf, size_t count)
	Attempt to read up to count bytes from file descriptor fd into the buffer starting at buf. More...
ssize_t	write (int fd, const void *buf, size_t count)
	Write up to count bytes from the buffer starting at buf to the file referred to by the file descriptor fd. More...
off_t	lseek (int fd, long offset, int whence)
	Reposition the file offset of the open file description associated with the file descriptor fd. More...
pid_t	getpid (void)
	Return the ID of the calling task. More...
pid_t	getppid (void)
	Return the ID of the task that started the calling one. Every task of Tenok is started by the one that brings the system up. More...
char *	getcwd (char *buf, size_t size)
	Get current working directory. More...
int	chdir (const char *path)
	Change working directory. More...
int	unlink (const char *pathname)
	Delete a name from the file system. More...
int	rmdir (const char *pathname)
	Delete a directory, which must be empty. More...
long	sysconf (int name)
int	isatty (int fd)
	Tell whether a descriptor refers to a terminal. More...
int	access (const char *pathname, int mode)
	Check whether the calling task can reach a file the way it asks. More...
uid_t	getuid (void)
	Report the user a task runs as, which on Tenok is always root. More...
int	setuid (uid_t uid)
	Become the user of the given identifier. Tenok runs as the one user it has, so only that one can be become. More...
int	seteuid (uid_t uid)
	Become the effective user of the given identifier, the way setuid() does. More...
uid_t	geteuid (void)
gid_t	getgid (void)
	Report the group a task runs as, which on Tenok is always root. More...
int	setgid (gid_t gid)
	Join the group of the given identifier. Tenok has the one group, so only that one can be joined. More...
int	setegid (gid_t gid)
	Join the effective group of the given identifier, the way setgid() does. More...
gid_t	getegid (void)
int	getgroups (int size, gid_t list[])
	Report the supplementary groups of the task. Tenok has one group and root is in it, so there is never a supplementary one. More...
int	link (const char *oldpath, const char *newpath)
	Give a file a second name. Tenok gives a file one name. More...
int	symlink (const char *target, const char *linkpath)
	Make a name that stands for another. Tenok has no symbolic link. More...
int	readlink (const char *pathname, char *buf, size_t bufsiz)
	Read what a symbolic link stands for. Nothing a path of Tenok names is one. More...
int	fchdir (int fd)
	Change the working directory to the one the descriptor names. Tenok keeps no way back from a descriptor to the name it was opened by. More...
int	ttyname_r (int fd, char *buf, size_t buflen)
	Name the terminal the descriptor is open on. Tenok keeps no way back from a descriptor to the name it was opened by. More...
int	chroot (const char *path)
	Make the given directory the root. The root of Tenok is the whole of what it mounted, with nothing outside to be shut away from. More...
int	chown (const char *pathname, uid_t owner, gid_t group)
	Replace the owner of a file. Tenok has one user, so only a request that names it can be granted. More...
int	lchown (const char *pathname, uid_t owner, gid_t group)
	Replace the owner of a file without following a symbolic link. Tenok has no symbolic link, so this is chown() More...

Macro Definition Documentation

sysconf

#define sysconf   _sysconf

Report a value of the system that is decided when it is built.

Parameters

name	One of the SC values.

Return values

long	The value on success and -1 when Tenok has no such value, with the reason left in errno.

Function Documentation

access()

int access	(	const char *	pathname,
		int	mode
	)

Check whether the calling task can reach a file the way it asks.

Parameters

pathname	The pathname of the file to check.
mode	F_OK, or the R_OK, W_OK and X_OK to check for.

Return values

int	0 on success and -1 on error, with the reason left in errno.

chdir()

int chdir

(

const char *

path

)

Change working directory.

Parameters

path	Pathname of the new working directory.

Return values

int	0 on success and -1 on error, with the reason left in errno.

chown()

int chown	(	const char *	pathname,
		uid_t	owner,
		gid_t	group
	)

Replace the owner of a file. Tenok has one user, so only a request that names it can be granted.

Parameters

pathname	The pathname of the file.
owner	The user to give it to, or -1 to leave it alone.
group	The group to give it to, or -1 to leave it alone.

Return values

int	0 on success and -1 on error, with the reason left in errno.

chroot()

int chroot

(

const char *

path

)

Make the given directory the root. The root of Tenok is the whole of what it mounted, with nothing outside to be shut away from.

Parameters

path	The directory to make the root.

Return values

int	-1 with errno set to ENOSYS.

close()

int close

(

int

fd

)

Close a file descriptor, so that it no longer refers to any file and may be reused.

Parameters

fd	The file descriptor to provide.

Return values

int	0 on success and -1 on error, with the reason left in errno.

dup()

int dup

(

int

oldfd

)

Create a copy of the file descriptor oldfd, using the lowest-numbered unused file descriptor for the new descriptor.

Parameters

oldfd

The file descriptor to duplicate.

Return values

int	The new file descriptor on success and -1 on error, with the reason left in errno.

dup2()

int dup2	(	int	oldfd,
		int	newfd
	)

Perform the same task as dup(), but use the file descriptor number specified by newfd.

Parameters

oldfd	The file descriptor to duplicate.
newfd	The number to specify the new file descriptor.

Return values

int	The new file descriptor on success and -1 on error, with the reason left in errno.

execve()

int execve	(	const char *	pathname,
		char *const	argv[],
		char *const	envp[]
	)

Replace the running program with the one the pathname names. No file of Tenok is in a format the system can execute, so the call always fails.

Parameters

pathname	The pathname of the program.
argv	The arguments to hand the program.
envp	The environment to hand the program.

Return values

int	-1 with errno set to ENOEXEC.

execvp()

int execvp	(	const char *	file,
		char *const	argv[]
	)

Replace the running program with the one found by searching PATH for the file, the way execve() does.

Parameters

file	The name of the program to search for.
argv	The arguments to hand the program.

Return values

int	-1 with errno set to ENOEXEC.

fchdir()

int fchdir

(

int

fd

)

Change the working directory to the one the descriptor names. Tenok keeps no way back from a descriptor to the name it was opened by.

Parameters

fd	The descriptor of the directory.

Return values

int	-1 with errno set to ENOSYS.

fork()

pid_t fork

(

void

)

Create a child process, the way vfork() does not either.

Return values

pid_t

-1 with errno set to ENOSYS.

getcwd()

char* getcwd	(	char *	buf,
		size_t	size
	)

Get current working directory.

Parameters

buf	Buffer space for storing path of the current working space.
size	Size of the buffer space.
buf	Buffer space for storing path of the current working space, or a null pointer to ask for one that free() takes back.

Return values

char	*: The buffer on success and a null pointer on error, with the reason left in errno.

getgid()

gid_t getgid

(

void

)

Report the group a task runs as, which on Tenok is always root.

Return values

gid_t

Always 0.

getgroups()

int getgroups	(	int	size,
		gid_t	list[]
	)

Report the supplementary groups of the task. Tenok has one group and root is in it, so there is never a supplementary one.

Parameters

size	How many the list holds.
list	For returning the groups.

Return values

int

Always 0.

getpid()

pid_t getpid

(

void

)

Return the ID of the calling task.

Return values

pid_t

The task ID.

getppid()

pid_t getppid

(

void

)

Return the ID of the task that started the calling one. Every task of Tenok is started by the one that brings the system up.

Return values

pid_t

Always 1.

getuid()

uid_t getuid

(

void

)

Report the user a task runs as, which on Tenok is always root.

Return values

uid_t

Always 0.

isatty()

int isatty

(

int

fd

)

Tell whether a descriptor refers to a terminal.

Parameters

fd	The file descriptor to provide.

Return values

int	One when it does, and zero when it does not, with the reason left in errno.

lchown()

int lchown	(	const char *	pathname,
		uid_t	owner,
		gid_t	group
	)

Replace the owner of a file without following a symbolic link. Tenok has no symbolic link, so this is chown()

Parameters

pathname	The pathname of the file.
owner	The user to give it to, or -1 to leave it alone.
group	The group to give it to, or -1 to leave it alone.

Return values

int	0 on success and -1 on error, with the reason left in errno.

link()

int link	(	const char *	oldpath,
		const char *	newpath
	)

Give a file a second name. Tenok gives a file one name.

Parameters

oldpath	The file to name again.
newpath	The name to give it.

Return values

int	-1 with errno set to ENOSYS.

lseek()

off_t lseek	(	int	fd,
		long	offset,
		int	whence
	)

Reposition the file offset of the open file description associated with the file descriptor fd.

Parameters

fd	The file descriptor to provide.
offset	The new offset to the position specified by whence.
whence	The start position of the new offset.

Return values

off_t

The new offset on success and -1 on error, with the reason left in errno.

pipe()

int pipe

(

int

pipefd[2]

)

Create a pipe, a stream that is written to through one descriptor and read from through the other.

Parameters

pipefd

Where to store the two descriptors, the read end first and the write end second.

Return values

int	0 on success and -1 on error, with the reason left in errno.

read()

ssize_t read	(	int	fd,
		void *	buf,
		size_t	count
	)

Attempt to read up to count bytes from file descriptor fd into the buffer starting at buf.

Parameters

fd	The file descriptor to provide.
buf	The memory space for storing read data.
count	The number of bytes to read.

Return values

int	0 on success and -1 on error, with the reason left in errno.

readlink()

int readlink	(	const char *	pathname,
		char *	buf,
		size_t	bufsiz
	)

Read what a symbolic link stands for. Nothing a path of Tenok names is one.

Parameters

pathname	The name to read.
buf	Where to put what it stands for.
bufsiz	The room there is for it.

Return values

int	-1 with errno set to EINVAL, which is what POSIX says of a name that is not a symbolic link.

rmdir()

int rmdir

(

const char *

pathname

)

Delete a directory, which must be empty.

Parameters

pathname

The pathname of the directory to remove.

Return values

int	0 on success and -1 on error, with the reason left in errno.

setegid()

int setegid

(

gid_t

gid

)

Join the effective group of the given identifier, the way setgid() does.

Parameters

gid	The group to join.

Return values

int	0 for the group Tenok runs as, and -1 with errno set to EPERM for any other.

seteuid()

int seteuid

(

uid_t

uid

)

Become the effective user of the given identifier, the way setuid() does.

Parameters

uid	The user to become.

Return values

int	0 for the user Tenok runs as, and -1 with errno set to EPERM for any other.

setgid()

int setgid

(

gid_t

gid

)

Join the group of the given identifier. Tenok has the one group, so only that one can be joined.

Parameters

gid	The group to join.

Return values

int	0 for the group Tenok runs as, and -1 with errno set to EPERM for any other.

setsid()

pid_t setsid

(

void

)

Start a session. Tenok has the one console and no sessions to give it out to.

Return values

pid_t

-1 with errno set to ENOSYS.

setuid()

int setuid

(

uid_t

uid

)

Become the user of the given identifier. Tenok runs as the one user it has, so only that one can be become.

Parameters

uid	The user to become.

Return values

int	0 for the user Tenok runs as, and -1 with errno set to EPERM for any other.

sleep()

unsigned int sleep

(

unsigned int

seconds

)

To cause the calling thread to sleep either until the number of real-time seconds specified in seconds have elapsed or until a signal arrives which is not ignored.

Parameters

seconds

The sleep seconds to provide.

Return values

int	0 on success and nonzero error number on error.

symlink()

int symlink	(	const char *	target,
		const char *	linkpath
	)

Make a name that stands for another. Tenok has no symbolic link.

Parameters

target	What the name would stand for.
linkpath	The name to make.

Return values

int	-1 with errno set to ENOSYS.

ttyname_r()

int ttyname_r	(	int	fd,
		char *	buf,
		size_t	buflen
	)

Name the terminal the descriptor is open on. Tenok keeps no way back from a descriptor to the name it was opened by.

Parameters

fd	The descriptor.
buf	Where to put the name.
buflen	The room there is for it.

Return values

int

ENOSYS.

unlink()

int unlink

(

const char *

pathname

)

Delete a name from the file system.

Parameters

pathname

The pathname of the file to remove.

Return values

int	0 on success and -1 on error, with the reason left in errno.

usleep()

int usleep

(

useconds_t

usec

)

Suspend execution of the calling thread for a given time in microseconds.

Parameters

usec	The sleep microseconds to provide.

Return values

int	0 on success and nonzero error number on error.

vfork()

pid_t vfork

(

void

)

Create a child process. Tenok runs every task from the image it booted and has no way to make another, so the call always fails.

Return values

pid_t

-1 with errno set to ENOSYS.

write()

ssize_t write	(	int	fd,
		const void *	buf,
		size_t	count
	)

Write up to count bytes from the buffer starting at buf to the file referred to by the file descriptor fd.

Parameters

fd	The file descriptor to provide.
buf	The data to write.
count	The number of bytes to write.

Return values

int	0 on success and -1 on error, with the reason left in errno.