NetBSD/lib/libc/sys/symlink.2

.\"	$NetBSD: symlink.2,v 1.26 2013/07/29 11:40:04 njoly Exp $
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.\"     @(#)symlink.2	8.1 (Berkeley) 6/4/93
.\"
.Dd July 29, 2013
.Dt SYMLINK 2
.Os
.Sh NAME
.Nm symlink ,
.Nm symlinkat
.Nd make symbolic link to a file
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn symlink "const char *name1" "const char *name2"
.Ft int
.Fn symlinkat "const char *name1" "int fd" "const char *name2"
.Sh DESCRIPTION
A symbolic link
.Fa name2
is created to
.Fa name1
.Pf ( Fa name2
is the name of the
file created,
.Fa name1
is the string
used in creating the symbolic link).
Either name may be an arbitrary path name; the files need neither
to be on the same file system nor to exist.
.Pp
.Fn symlinkat
works the same way as
.Fn symlink
except if
.Fa path2
is relative.
In that case, it is looked up from a directory whose file
descriptor was passed as
.Fa fd .
Search permission is required on this directory.
.\"    (These alternatives await a decision about the semantics of O_SEARCH)
.\" Search permission is required on this directory
.\" except if
.\" .Fa fd
.\" was opened with the
.\" .Dv O_SEARCH
.\" flag.
.\"    - or -
.\" This file descriptor must have been opened with the
.\" .Dv O_SEARCH
.\" flag.
.Fa fd
can be set to
.Dv AT_FDCWD
in order to specify the current directory.
.Sh RETURN VALUES
.Rv -std symlink symlinkat
.Sh ERRORS
.Fn symlink
and
.Fn symlinkat
will fail and no link will be created if:
.Bl -tag -width Er
.It Bq Er EACCES
A component of the
.Fa name2
path prefix denies search permission.
.It Bq Er EDQUOT
The directory in which the entry for the new symbolic link
is being placed cannot be extended because the
user's quota of disk blocks on the file system
containing the directory has been exhausted.
Or, the new symbolic link cannot be created because the user's
quota of disk blocks on the file system that will
contain the symbolic link has been exhausted.
Or, the user's quota of inodes on the file system on
which the symbolic link is being created has been exhausted.
.It Bq Er EEXIST
.Fa name2
already exists.
.It Bq Er EFAULT
.Fa name1
or
.Fa name2
points outside the process's allocated address space.
.It Bq Er EIO
An I/O error occurred while making the directory entry for
.Fa name2 ,
or allocating the inode for
.Fa name2 ,
or writing out the link contents of
.Fa name2 .
Or, an I/O error occurred while making the directory entry or allocating the inode.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Brq Dv NAME_MAX
characters, or an entire path name exceeded
.Brq Dv PATH_MAX
characters.
.It Bq Er ENOENT
A component of the
.Fa name2
path does not exist.
.It Bq Er ENOSPC
The directory in which the entry for the new symbolic link is being placed
cannot be extended because there is no space left on the file
system containing the directory.
Or, the new symbolic link cannot be created because there
there is no space left on the file
system that will contain the symbolic link.
Or, there are no free inodes on the file system on which the
symbolic link is being created.
.It Bq Er ENOTDIR
A component of the
.Fa name2
prefix is not a directory.
.It Bq Er EROFS
The file
.Fa name2
would reside on a read-only file system.
.El
.Pp
In addition,
.Fn symlinkat
will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa name2
does not specify an absolute path and
.Fa fd
is neither
.Dv AT_FDCWD
nor a valid file descriptor open for reading or searching.
.It Bq Er ENOTDIR
.Fa name2
is not an absolute path and
.Fa fd
is a file descriptor associated with a non-directory file.
.El
.Sh SEE ALSO
.Xr ln 1 ,
.Xr link 2 ,
.Xr readlink 2 ,
.Xr unlink 2 ,
.Xr symlink 7
.Sh STANDARDS
The
.Fn symlink
function conforms to
.St -p1003.1-90 .
.Fn symlinkat
conforms to
.St -p1003.1-2008 .
.Sh HISTORY
The
.Fn symlink
function call appeared in
.Bx 4.2 .