mknod

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).