mknod(2)
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mknod System Call
Make a directory, or a special or ordinary file.
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SYNTAX
#include <sys/types.h>
#include <sys/stat.h>
int mknod (path, mode, device)
char * path;
int mode;
int device;
PARAMETERS
path Address of a pathname.
mode Access mode of the new file.
device Device specifier.
DESCRIPTION
<Path> points to a pathname naming a file. Terminal symbolic
links are not followed if found in <path>. The file must not
exist. The indicated file must be on a file system device
mounted read-write.
<Device> is only pertinent if the file being created is a block
or character special file, in which case it is a configuration-
dependent specification of a block or character I/O device.
The file's mode (st_mode) is initialized from <mode>. The values
of <mode> are constructed by or-ing flags from the following
list:
file type: (only one may be specified)
S_IFIFO 0010000 FIFO special.
S_IFCHR 0020000 Character special.
S_IFDIR 0040000 Directory.
S_IFBLK 0060000 Block special.
S_IFREG 0100000 Ordinary file.
execution mode bits: (any combination)
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S_ISUID 0004000 Set user id.
S_ISGID 0002000 Set group id.
S_ISVTX 0001000 Sticky bit.
protection rights: (any combination)
S_IRUSR 0000400 Read by owner.
S_IWUSR 0000200 Write by owner.
S_IXUSR 0000100 Execute by owner.
S_IRGRP 0000040 Read by group.
S_IWGRP 0000020 Write by group.
S_IXGRP 0000010 Execute by group.
S_IROTH 0000004 Read by other.
S_IWOTH 0000002 Write by other.
S_IXOTH 0000001 Execute by other.
You cannot make symbolic links or socket files via the mknod
interface.
If a file type is not specified, it defaults to ordinary. Values
of <mode> other than those formed as described above are illegal.
<Mode> is modified by the process's file mode creation mask: all
bits set in the process's file mode creation mask are cleared
(see umask).
The file's other attributes are initialized as follows:
* The inode number (st_ino) is set to refer to the per-file
database allocated.
* The device number(st_dev) is set to the device code
containing the logical disk. If the file is block or
character special, the represented device (st_rdev) is set
to <device>. For other file types, the represented device
is undefined.
* The number of links (st_nlink) is set to one.
* The file size (st_size) is zero.
* The user id (st_uid) is set to the effective user id of the
calling process. The group id (st_gid) is set to the
effective group id of the calling process.
* The time last accessed (st_atime), time last modified
(st_mtime), and time of last attribute change (st_ctime) are
set to the current time.
<Path> is created in the containing directory and is made to
identify the newly created file. The attributes of the directory
the file is contained in change as follows:
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* The file size (st_size) is updated.
* The time last modified (st_mtime) and time of last attribute
change (st_ctime) are set to the current time.
If the call fails, the file is not created, and the attributes of
the directory the file is contained in are unchanged.
ACCESS CONTROL
Any process may create a FIFO file, but the effective user id of
the process must be superuser to create a directory, special
file, or ordinary file.
The process must have write access to the containing directory.
The process must have permission to resolve <path>.
RETURN VALUE
0 The new file was successfully created.
-1 An error occurred. Errno is set to indicate the
error.
EXCEPTIONS
Errno may be set to one of the following error codes:
EEXIST The named file exists.
EINVAL An invalid file type was specified in <mode>.
EROFS The directory in which the file is to be created
is located on a file system device mounted read-
only
ENOSPC No more contiguous space left to allocate file
space or an inode.
ENOENT A non-terminal component of the pathname does not
exist.
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ENOTDIR A non-terminal component of the pathname was not a
directory or symbolic link.
ENAMETOOLONG The pathname exceeds the length limit for
pathnames.
ENAMETOOLONG A component of the pathname exceeds the length
limit for filenames.
ENOMEM There are not enough system resources to resolve
the pathname or to expand a symbolic link.
ELOOP The number of symbolic links encountered during
pathname resolution exceeded MAXSYMLINKS. A
symbolic link cycle is suspected.
EPERM Permission to create a directory, special file, or
ordinary file is denied.
EPERM The pathname contains a character not in the
allowed character set.
EFAULT The pathname does not completely reside in the
process's address space or the pathname does not
terminate in the process's address space.
SEE ALSO
The related manual sections: mkdir(1),
chmod(2), exec(2), fstat(2), dg_mstat(2), lstat(2), stat(2),
umask(2),
stat(5).
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