NAME
mknod - create a directory or special or ordinary file
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
to specify a normal file (which will be created empty),
character special file, block special file or FIFO (named
pipe), respectively, or zero, which will create 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 spe-
cial 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 superuser; also
returned if the filesystem containing pathname does not
support the type of node requested.
EINVAL
mode requested creation of something other than a nor-
mal 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 permission 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.
ELOOP
Too many symbolic links were encountered in resolving
pathname.
ENOSPC
The device containing pathname has no room for the new
node.
CONFORMING TO
SVr4 (but the call requires privilege and is thus not in
POSIX), 4.4BSD. The Linux version differs from the SVr4
version in that it does not require root permission to
create pipes, also in that no EMULTIHOP, ENOLINK, or EINTR
error is documented.
BUGS
The mknod call 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.
Some of these affect mknod.
SEE ALSO
read(2), write(2), fcntl(2), unlink(2), open(2), mkdir(2),
mount(2), socket(2), fopen(3).