MKNOD(2)            Linux Programmer's Manual            MKNOD(2)

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  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 filesys-
              tem.

       ELOOP  Too many symbolic links were encountered in resolv-
              ing 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), close(2), unlink(2), open(2),
       mkdir(2),   stat(2),   umask(2),   mount(2),    socket(2),
       fopen(3).

Linux 1.0                 29 March 1994                         1