mknod
Hurricane Electric Internet Services
NAME
mknod - create a directory
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int mknod(const char *pathname, mode_t mode, dev_t dev);
DESCRIPTION
mknod attempts to create a filesystem node (file, device
special file or named pipe) named pathname, specified by
mode and dev.
mode specifies both the permissions to use and the type of
node to be created.
It should be a combination (using bitwise OR) of one of
the file types listed below and the permissions for the
new node.
The permissions are modified by the process's umask in the
usual way: the permissions of the created node are (mode &
~umask).
The file type should be one of S_IFREG, S_IFCHR, S_IFBLK
and S_IFIFO to specify a normal file (which will be cre-
ated empty), character special file, block special file or
FIFO (named pipe), respectively, or zero, which will cre-
ate a normal file.
If the file type is S_IFCHR or S_IFBLK then dev specifies
the major and minor numbers of the newly created device
special file; otherwise it is ignored.
The newly created node will be owned by the effective uid
of the process. If the directory containing the node has
the set group id bit set, or if the filesystem is mounted
with BSD group semantics, the new node will inherit the
group ownership from its parent directory; otherwise it
will be owned by the effective gid of the process.
RETURN VALUE
mknod returns zero on success, or -1 if an error occurred
(in which case, errno is set appropriately).
ERRORS
EPERM mode requested creation of something other than a
FIFO (named pipe), and the caller is not the supe-
ruser; also returned if the filesystem containing
pathname does not support the type of node
requested. EINVAL mode requested creation of
something other than a normal file, device special
file or FIFO. EEXIST pathname already exists.
EFAULT pathname points outside your accessible address
space.
EACCES The parent directory does not allow write permis-
sion to the process, or one of the directories in
pathname did not allow search (execute) permission.
ENAMETOOLONG
pathname was too long.
ENOENT A directory component in pathname does not exist or
is a dangling symbolic link.
ENOTDIR
A component used as a directory in pathname is not,
in fact, a directory.
ENOMEM Insufficient kernel memory was available.
EROFS pathname refers to a file on a read-only filesystem
and write access was requested.
ELOOP pathname contains a reference to a circular sym-
bolic link, ie a symbolic link whose expansion con-
tains a reference to itself.
ENOSPC The device containing pathname has no room for the
new node.
CONFORMING TO
BUGS
In some older versions of Linux (for example, 0.99pl7) all
the normal filesystems sometime allow the creation of two
files in the same directory with the same name. This
occurs only rarely and only on a heavily loaded system.
It is believed that this bug was fixed in the Minix
filesystem in Linux 0.99pl8 pre-release; and it is hoped
that it was fixed in the other filesystems shortly after-
wards.
mknod cannot be used to create directories or socket
files, and cannot be used to create normal files by users
other than the superuser.
There are many infelicities in the protocol underlying
NFS.
SEE ALSO
read(2), write(2), fcntl(2), close(2), unlink(2), open(2),
mkdir(2), stat(2), umask(2), mount(2), socket(2),
socket(2), fopen(3).
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.