mknodat

       #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);

       #include <fcntl.h>           /* Definition of AT_* constants */
       #include <sys/stat.h>

       int mknodat(int dirfd, const char *pathname, mode_t mode, dev_t dev);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       mknod():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
           _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

DESCRIPTION
       The system call mknod() creates a filesystem node (file, device special
       file,  or named pipe) named pathname, with attributes specified by mode
       and dev.

       The mode argument specifies both the file mode 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 zero or more of  the  file  mode
       bits listed in stat(2).

       The  file  mode is modified by the process's umask in the usual way: in
       the absence of a default ACL, the permissions of the created  node  are
       (mode & ~umask).

       The  file  type  must  be one of S_IFREG, S_IFCHR, S_IFBLK, S_IFIFO, or
       S_IFSOCK to specify a regular file (which will be created empty), char-
       acter  special  file,  block  special  file, FIFO (named pipe), or UNIX
       domain socket, respectively.  (Zero file type  is  equivalent  to  type
       S_IFREG.)

       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  (makedev(3)
       may be useful to build the value for dev); otherwise it is ignored.

       If pathname already exists, or is a symbolic link, this call fails with
       an EEXIST error.

       The newly created node will be owned by the effective user  ID  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; other-
       wise it will be owned by the effective group ID of the process.

   mknodat()
       The mknodat() system call operates in exactly the same way as mknod(2),
       except for the differences described here.
       See openat(2) for an explanation of the need for mknodat().

RETURN VALUE
       mknod() and mknodat() return  zero  on  success,  or  -1  if  an  error
       occurred (in which case, errno is set appropriately).

ERRORS
       EACCES The  parent  directory  does  not  allow write permission to the
              process, or one of the directories in the path prefix  of  path-
              name  did  not  allow search permission.  (See also path_resolu-
              tion(7).)

       EDQUOT The user's quota of disk blocks or inodes on the filesystem  has
              been exhausted.

       EEXIST pathname  already exists.  This includes the case where pathname
              is a symbolic link, dangling or not.

       EFAULT pathname points outside your accessible address space.

       EINVAL mode requested creation of something other than a regular  file,
              device special file, FIFO or socket.

       ELOOP  Too many symbolic links were encountered in resolving pathname.

       ENAMETOOLONG
              pathname was too long.

       ENOENT A  directory  component  in pathname does not exist or is a dan-
              gling symbolic link.

       ENOMEM Insufficient kernel memory was available.

       ENOSPC The device containing pathname has no room for the new node.

       ENOTDIR
              A component used as a directory in pathname is not, in  fact,  a
              directory.

       EPERM  mode  requested creation of something other than a regular file,
              FIFO (named pipe), or UNIX domain socket, and the caller is  not
              privileged (Linux: does not have the CAP_MKNOD capability); also
              returned if the filesystem containing pathname does not  support
              the type of node requested.

       EROFS  pathname refers to a file on a read-only filesystem.

       The following additional errors can occur for mknodat():

       EBADF  dirfd is not a valid file descriptor.

       ENOTDIR
              pathname is relative and dirfd is a file descriptor referring to
              a file other than a directory.

       FIFO-special file.  If mode is not S_IFIFO or dev is not 0, the  behav-
       ior of mknod() is unspecified."  However, nowadays one should never use
       mknod() for this purpose; one should use mkfifo(3),  a  function  espe-
       cially defined for this purpose.

       Under  Linux, mknod() cannot be used to create directories.  One should
       make directories with mkdir(2).

       There are many infelicities in the protocol underlying  NFS.   Some  of
       these affect mknod() and mknodat(2).

SEE ALSO
       chmod(2),  chown(2),  fcntl(2), mkdir(2), mount(2), socket(2), stat(2),
       umask(2), unlink(2), makedev(3), mkfifo(3), acl(5) path_resolution(7)

COLOPHON
       This page is part of release 4.04 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       http://www.kernel.org/doc/man-pages/.

Linux                             2015-05-07                          MKNOD(2)
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