Provided by: libparanoid-perl_0.36-3_all 
NAME
Paranoid::Input - Paranoid input functions
VERSION
$Id: Input.pm,v 0.20 2011/04/13 22:01:43 acorliss Exp $
SYNOPSIS
use Paranoid::Input;
FSZLIMIT = 64 * 1024;
LNSZLIMIT = 2 * 1024;
$rv = slurp($filename, \@lines);
$rv = sip($filename, \@lines);
$rv = sip($filename, \@lines, 1);
$rv = tail($filename, \@lines);
$rv = tail($filename, \@lines, -100);
$rv = tail($filename, \@lines, -100, 1);
$rv = closeFile($filename);
addTaintRegex("telephone", qr/\(\d{3}\)\s+\d{3}-\d{4}/);
$rv = detaint($userInput, "login", \$val);
$rv = stringMatch($input, @strings);
DESCRIPTION
The modules provide safer routines to use for input activities such as reading files and detainting user
input.
The sip and tail functions keep open file handles. Even so, it's specifically built to be safe for use
in fork scenarios. You can being a tail or sip in a parent, fork children, and all process can
independently continue sipping with no confusion between processes. This is possible because we check to
see if the PID matches the PID in effect with the file was opened. If not, we reopen the file and seek
to the same position so we can pick up where we left off.
The slurp function isn't affected by this since it reads entire files in a single call, no filehandles
are kept open between calls.
All file-reading functions use and obey flock.
addTaintRegex is only exported if this module is used with the :all target.
SUBROUTINES/METHODS
FSZLIMIT
The value returned/set by this lvalue function is the maximum file size that will be read into memory.
This affects functions like slurp (documented below). Unless explicitly set this defaults to 16KB.
LNSZLIMIT
The valute returned/set by this lvalue function is the maximum line length supported by functions like
sip (documented below). Unless explicitly set this defaults to 2KB.
slurp
$rv = slurp($filename, \@lines);
This function allows you to read a text file in its entirety into memory, the lines of which are placed
into the passed array reference. This function will only read files up to FSZLIMIT in size. Flocking is
used (with LOCK_SH) and the read is a blocking read.
An optional third argument sets a boolean flag which, if true, determines if all lines are automatically
chomped. If chomping is enabled this will strip both UNIX and DOS line separators.
The return value is false if the read was unsuccessful or the file's size exceeded FSZLIMIT. In the
latter case the array reference will still be populated with what was read. The reason for the failure
can be retrieved from Paranoid::ERROR.
sip
$rv = sip($filename, \@lines);
$rv = sip($filename, \@lines, 1);
This function allows you to read a text file into memory in chunks, the lines of which are placed into
the passed array reference. The chunks are read in at up to FSZLIMIT in size at a time. Like slurp file
locking is used and autochomping is also supported.
This function returns true if there was input read, but if any or all of the input splits into lines
greater than LNSZLIMIT it will discard that input and return -1 (which is still technically boolean
true).
The reason why we now care about line lengths is because it's very likely that line boundaries will not
fall neatly along our chunk boundaries, so we need to take trailing portions of unterminated lines and
store them to be joined with the remainder from the next sip.
When sip comes up to then end of the file it does not close the file, you're required to close it
explicitly with closeFile. This is done intentionally to allow the process to continue to effectively
tail a growing file. Unlike the tail function provided here, though, it does perform any additional
checks to see if the file you're reading was truncated or replaced.
An optional third argument tells sip whether or not to chomp all the read lines before returning.
tail
$rv = tail($filename, \@lines);
$rv = tail($filename, \@lines, -100);
$rv = tail($filename, \@lines, -100, 1);
The only difference between this function and sip is that tail opens the file and immediately seeks to
the end. If an optional third argument is passed it will seek backwards to extract and return that
number of lines (if possible). Depending on the number passed one must be prepared for enough memory to
be allocated to store LNSZLIMIT * that number.
This function returns true if the file is successfully open, regardless of whether any new input was
there to be read. It only returns false if there was a problem opening or reading the file.
Tail should be called with the third argument for the first tail of a file. Continuing to use it for
subsequent calls will cause the number of lines returned to be truncated to fit within that limit.
Like sip, one must explicitly close a file with closeFile.
closeFile
$rv = closeFile($filename);
This function closes any open file descriptors that may have been opened via sip or tail for the named
file. This returns the value of the close function if the file was open, otherwise it returns true.
addTaintRegex
addTaintRegex("telephone", qr/\(\d{3}\)\s+\d{3}-\d{4}/);
This adds a regular expression which can used by name to detaint user input via the detaint function.
This will allow you to overwrite the internally provided regexes or as well as your own.
detaint
$rv = detaint($userInput, "login", \$val);
This function populates the passed reference with the detainted input from the first argument. The
second argument specifies the type of data in the first argument, and is used to validate the input
before detainting. The following data types are currently known:
alphabetic ^([a-zA-Z]+)$
alphanumeric ^([a-zA-Z0-9])$
email ^([a-zA-Z][\w\.\-]*\@
(?:[a-zA-Z0-9][a-zA-Z0-9\-]*\.)*
[a-zA-Z0-9]+)$
filename ^[/ \w\-\.:,@\+]+\[?$
fileglob ^[/ \w\-\.:,@\+\*\?\{\}\[\]]+\[?$
hostname ^(?:[a-zA-Z0-9][a-zA-Z0-9\-]*\.)*
[a-zA-Z0-9]+)$
ipaddr ^(?:\d+\.){3}\d+$
netaddr ^(?:\d+\.){3}\d+(?:/(?:\d+|
(?:\d+\.){3}\d+))?$
login ^([a-zA-Z][\w\.\-]*)$
nometa ^([^\`\$\!\@]+)$
number ^([+\-]?[0-9]+(?:\.[0-9]+)?)$
If the first argument fails to match against these regular expressions the function will return 0. If
the string passed is either undefined or a zero-length string it will also return 0. And finally, if you
attempt to use an unknown (or unregistered) data type it will also return 0, and log an error message in
Paranoid::ERROR.
NOTE: This is a small alteration in previous behavior. In previous versions if an undef or zero-length
string was passed, or if the data type was unknown the code would croak. That was, perhaps, a tad
overzealous on my part.
stringMatch
$rv = stringMatch($input, @strings);
This function does a multiline case insensitive regex match against the input for every string passed for
matching. This does safe quoted matches (\Q$string\E) for all the strings, unless the string is a perl
Regexp (defined with qr//) or begins and ends with /.
NOTE: this performs a study in hopes that for a large number of regexes will be performed faster. This
may not always be the case.
DEPENDENCIES
o Fcntl
o Paranoid
o Paranoid::Debug
BUGS AND LIMITATIONS
If you fork a process that's already opened a file with sip or tail a new file descriptor will be opened
for the child process. But what may be less obvious is that with a newly opened file descriptor you will
be starting back from the beginning (or end, in the case of tail) of the file, rather than from where
ever you were before the fork.
AUTHOR
Arthur Corliss (corliss@digitalmages.com)
LICENSE AND COPYRIGHT
This software is licensed under the same terms as Perl, itself. Please see http://dev.perl.org/licenses/
for more information.
(c) 2005, Arthur Corliss (corliss@digitalmages.com)