NAME

mknod − make a directory, or a special or ordinary file

SYNOPSIS

#include <sys/types.h>
#include <sys/stat.h>

int mknod(const char ∗path, mode_t mode, dev_t dev);

DESCRIPTION

mknod creates a new file named by the path name pointed to by path. The file type and permissions of the new file are initialized from mode.

The file type is specified in mode by the S_IFMT bits, which must be set to one of the following values:

The file access permissions are specified in mode by the 0007777 bits, and may be constructed by an OR of the following values:

The owner ID of the file is set to the effective user ID of the process.  The group ID of the file is set to the effective group ID of the process.  However, if the S_ISGID bit is set in the parent directory, then the group ID of the file is inherited from the parent.  If the group ID of the new file does not match the effective group ID or one of the supplementary group IDs, the S_ISGID bit is cleared. 

The access permission bits of mode are modified by the process’s file mode creation mask: all bits set in the process’s file mode creation mask are cleared [see umask(2)]. 

For block and character special files, dev is the special file’s device number.  For name special files, dev is the file type of the name file, either a XENIX shared data file (S_INSHD) or a XENIX semaphore (S_INSEM).  Otherwise, dev is ignored. 

mknod may be invoked only by a privileged user for file types other than FIFO special or special named files. 

If path is a symbolic link, mknod returns EEXIST because mknod does not follow symbolic links. 

mknod fails and creates no new file if one or more of the following are true:

EEXIST The named file exists. 

EINVAL dev is invalid. 

EFAULT path points outside the allocated address space of the process. 

ELOOP Too many symbolic links were encountered in translating path. 

EMULTIHOP Components of path require hopping to multiple remote machines and the file system type does not allow it. 

ENAMETOOLONG The length of the path argument exceeds {PATH_MAX}, or the length of a path component exceeds {NAME_MAX} while _POSIX_NO_TRUNC is in effect. 

ENOTDIR A component of the path prefix is not a directory. 

ENOENT A component of the path prefix does not exist or is a null pathname. 

EPERM The effective user ID of the process is not super-user. 

EROFS The directory in which the file is to be created is located on a read-only file system. 

ENOSPC No space is available. 

EINTR A signal was caught during the mknod system call. 

ENOLINK path points to a remote machine and the link to that machine is no longer active. 

SEE ALSO

mkdir(1), creatsem(2), chmod(2), exec(2), sdget(2), umask(2), makedev(3C), mkfifo(3C), fs(4), share(1M), stat(5). 

DIAGNOSTICS

Upon successful completion a value of 0 is returned.  Otherwise, a value of −1 is returned and errno is set to indicate the error. 

NOTES

If mknod creates a device in a remote directory using Remote File Sharing, the major and minor device numbers are interpreted by the server. 

If mknod attempts to create a device in a remote directory using NFS, the client and server must agree that the client is root.  This is normally done with the share(1M) command. The created device is dependent on the servers notion of devices. 

Semaphore files should be created with the creatsem system call.  Shared data files should be created with the sdget system call.