Free wireless pc lock software for linux

File::BasicFlock is a Perl module for file locking with flock.

SYNOPSIS

use File::BasicFlock;

lock($filename);

lock($filename, shared);

lock($filename, undef, nonblocking);

lock($filename, shared, nonblocking);

unlock($filename);

Lock files using the flock() call. The file to be locked must already exist. This is a very thing interface.

File::lockf is a Perl module interface to the lockf system call.

SYNOPSIS

use File::lockf;

File-Lockf is an interface to the lockf system call. Perl supports the flock system call natively, but that does not acquire network locks. Perl also supports the fcntl system call, but that is somewhat ugly to use. There are other locking modules available for Perl, but none of them provided what I wanted -- a simple, clean interface to the lockf system call, without any bells or whistles getting in the way.

File-Lockf contains four functions which map directly to the four modes of lockf, and an OO wrapper class that encapulates the basic locking functionality along with an additional utility method that iteratively attempts to acquire a lock.

Lock functions

The following functions return 0 (zero) on success, and the system error number from errno on failure. They each take an open file handle as the first argument, and optionally a size parameter. Please see your system lockf man page for more details about lockf functionality on your system.

$status = File::lockf::lock(FH, size = 0)
This function maps to the F_LOCK mode of lockf.

$status = File::lockf::tlock(FH, size = 0)
This function maps to the F_TLOCK mode of lockf.

$status = File::lockf::ulock(FH, size = 0)
This function maps to the F_ULOCK mode of lockf.

$status = File::lockf::test(FH, size = 0)
This function maps to the F_TEST mode of lockf.

OO wrapper

File-Lockf also provides a simple OO wrapper class around the locking functionality, which allows you to create a lock object for a file handle and then perform lock operations with it. All of the methods return 0 (zero) on success, and the system error number from errno on failure.

$lock = new File::lockf(*FH)

This function returns a new lock object bound to the given file handle. Note that you need to pass a reference to the file handle to the constructor, not the file handle itself.

$status = $lock->lock(size = 0)
This method calls File::lockf::lock on the bound file handle.

$status = $lock->tlock(size = 0)
This method calls File::lockf::tlock on the bound file handle.

$status = $lock->ulock(size = 0)
This method calls File::lockf::ulock on the bound file handle.

$status = $lock->test(size = 0)
This method calls File::lockf::test on the bound file handle.

$status = $lock->slock(count = 5, delay = 2, size = 0)
This method will attempt to lock the bound file handle < count > times, sleeping < delay > seconds after each try. It will return 0 if the lock succeeded, or the system error number from errno if all attempts fail.

File::LockDir is a Perl basic filename-level lock utility.

SYNOPSIS

use File::LockDir;

INTERFACE

new

Initializes the class. Returns the singleton object.

nflock($file, $nap_till, $locker, $lockhost)

Locks the supplied filename. Only $file is required.

$file is the file to be locked; $nap_till is the total amount of time to wait before giving up; $locker is a name identifying the locker; $lockhost is the host requesting the lock.

nunflock($file)

Unlocks the supplied file.

nlock_state($file)

Checks the state of the lock for the supplied file. Returns a list: the first item is true if the file is unlocked, and false if not; the second item is undef if the file is unlocked, and the identity (name and host) is it is locked.

DIAGNOSTICS

%s already locked

Seen when youve already locked the requested pathname. Informational only.

No pathname to be locked

You didnt supply a pathname to be locked to nflock. Fatal.

cant write to directory of %s

The directory where the file resides cant be written, so the lockfile cant be created.

cant get %s: %s

The named lock cant be gotten: the reason is supplied. Failure occurs after ten tries to get the lock.

%s %s[%s]: lock on %s held by %s

The lock on the specified file is help by the noted locker. Informatory message, printed only when debugging is on.

close failed for %s: %s

The file containing the lock information couldnt be closed for the reason shown.

releasing lock on %s

Debug message; notes that the lock on the specified file was successfully released.