Unix::Mknod - Perl extension for mknod, major, minor, and makedev
use Unix::Mknod qw(:all); use File::stat; use Fcntl qw(:mode); $st=stat('/dev/null'); $major=major($st->rdev); $minor=minor($st->rdev); mknod('/tmp/special', S_IFCHR|0600, makedev($major,$minor+1));
This module allows access to the device routines major()/minor()/makedev() that may or may not be macros in .h files.
It also allows access to the
mknod(2) system call.
- mknod($filename, $mode, $rdev)
Creates a block or character device special file named $filename. Must be run as a privileged user, usually root. Returns 0 on success and -1 on failure, like
- $major = major($rdev)
Returns the major number for the device special file as defined by the st_rdev field from the
- $minor = minor($rdev)
Returns the minor number for the device special file as defined by the st_rdev field from the
- $rdev = makedev($major, $minor)
Returns the st_rdev number for the device special file from the $major and $minor numbers.
There are 2 other perl modules that implement the
mknod(2) system call, but they have problems working on some platforms.
Sys::Mknod does not work on AIX because it uses the
syscall(2) generic system call which AIX does not have.
Mknod implements S_IFIFO, which on most platforms is not implemented in
mknod(1), but rather
mkfifo(1) (which is implemented in POSIX perl module).
The perl module
File::Stat::Bits also implements major() and minor() (and a version of makedev() called dev_join). They are done as a program to get the bit masks at compile time, but if major() and minor() are implemented as sub routines, the arugment could be something as simple as an index to a lookup table (and thereby having no decernable relation to its result).
make test as non root will not truly test the functions, as in most UNIX like OSes,
mknod(2) needs to be invoked by a privelaged user, usually root.
$! for the specific error message.
Jim Pirzyk, <firstname.lastname@example.org>
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