USAGE:

phook accepts by default the following command-line options:

./phook -p|--pid PID -f|--fd FD [ -w|--write STRING | -l|--load PLUGIN_NAME
	-r|--read NUM_BYTES -o|--output FILE [ -t|--timeout TIMEOUT ] ]

You have to choose either --read, --write or --load.

--write STRING		* Write the string STRING to the file descriptor specified
			    by --fd

--read NUM_BYTES	* Read NUM_BYTES bytes from the file descriptor specified
			    by --fd

--load PLUGIN_NAME	* Use the plugin PLUGIN_NAME. Command line options depends
			    upon the plugin.


When using --read or --write, the following options are mandatory (M):

M)	--pid	* The pid of the target application
M)	--fd	* The file descriptor you want to read/write from/to


With --read, you have the following options, which might be mandatory (M) or
 optional (O):

M)	--output   * Write the data stolen from the file descriptor to this
			output file
O)	--timeout  * Wait for data for the specified amount of seconds (integer).
			If timeout is 0, the plugin will wait *FOREVER*.


!!! IMPORTANT NOTE: WHEN READING FROM A FILE DESCRIPTOR YOUR APPLICATION WILL
 **HANG** UNTIL DATA IS RECEIVED OR THE TIMEOUT EXPIRES.
!!! REMEMBER THAT YOU ARE ACTUALLY **STEALING** DATA FROM THE FILE DESCRIPTOR
 AND THIS MEANS THAT YOUR TARGET APPLICATION **WON'T** BE ABLE TO READ THE DATA
 YOU'VE "STOLEN". THIS CAN MAKE YOUR APPLICATION UTTERLY FAIL IN AN UNEXPECTED WAY.



Well, let's start from a quite simple real example: you want to write into a
 network socket belonging to kvirc (which is a graphical IRC client).

$ ls -al /proc/`pidof kvirc`/fd | grep socket | cut -d " " -f 7-
22:23 12 -> socket:[715784]
22:23 13 -> socket:[762765]
22:23 3 -> socket:[715725]
22:23 4 -> socket:[715727]
22:23 9 -> socket:[715732]
		     ^
		     ^
		     |____ INODES

File descriptors 12, 13, 3, 4 and 9 are sockets, but we're only interested in tcp
 sockets.

$ SOCKETS="$(ls -al /proc/`pidof kvirc`/fd | egrep -o "socket:[[[:digit:]]+" | cut -d \[ -f 2)"
$ egrep "`echo $SOCKETS | tr " " "|"`" /proc/net/tcp
  11: xxxxxxxx:E432 yyyyyyyy:1A0B 01 00000000:00000000 00:00000000 00000000  1000    0 715784 1 caae5800 69 10 30 2 100
  13: xxxxxxxx:826E zzzzzzzz:1A0C 01 00000000:00000000 00:00000000 00000000  1000    0 762765 1 caae5400 74 10 30 2 2
											  ^
											  ^
											  |
								tcp INODES  ______________|

We can see a connection from xxxxx, port E432 (58418), to yyyy, port 1A0B (6667) and another 
  connection from xxxx, port 826E (33390), to zzzz, port 1A0C (6668). 
Numbers are in hexadecimal, just convert them with a calculator, for example using bc:

$ bc
ibase=16
e432
58418

1A0B
6667


Netstat may also be really useful:

$ netstat -A inet -p kvirc -n | grep kvirc
tcp        0      0 xx.xx.xx.xx:58418        yyy.yyy.yyy.yyy:6667    ESTABLISHED3984/kvirc
tcp        0      0 xx.xx.xx.xx:33390        zzz.zzz.zzz.zzz:6668    ESTABLISHED3984/kvirc

We want to write to the socket connected to zzz.zzz.zzz.zzz:6668, and so the inode 
  we're looking for is: 762765 (see the line prefixed by "13: " above)

As we can see here:  13 -> socket:[762765]
  13 is the socket number associated to inode 762765.


Finally we will start phook in WRITE MODE:

$ ./phook -p `pidof kvirc` -f 13 -w "
privmsg mynickonirc :wo, i'm writing this message from the console
"

Note how the " are used in order to send newlines to the irc server.


READ MODE works pretty much the same:

$ ./phook -p `pidof kvirc` -f 13 -r 1024 -o /tmp/blah -t 5

Here we're reading a maximum of 1024 bytes from file descriptor 13, with a timeout
  of 5 seconds. If data is available within this amount of time, it will be placed
  into the file /tmp/blah. If no data is received the time expires and NO OUTPUT
  files will be created.

**** REMEMBER TO SET A REASONABLE TIMEOUT SINCE WITH THE DEFAULT READ PLUGIN [not the
	forking one] YOUR APPLICATION WILL ELSE HANG UNTIL DATA IS RECEIVED.
     THE DEFAULT TIMEOUT IS ZERO, WHICH MEANS THAT THE APPLICATION WILL WAIT FOR 
	SOME DATA FOREVER !!! ****