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proc_open and pty's

By Harry Fuecks



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Something from my inbox (best read bottom up), following on from CLI Part 2 any takers?


Now i’m working now with PHP
Version 5.0.1


Version 5.0.0 Release Candidate 2* *25-Apr-2004


* Added pty support to proc_open(). (Wez)


PHP 5RC2 introduces pty support for systems with Unix98 ptys. This
allows your script to interact with applications that expect to be
talking to a terminal. A pty works like a pipe, but is bi-directional,
so there is no need to specify a read/write mode. The example below
shows how to use a pty; note that you don’t have to have all descriptors
talking to a pty. Also note that only one pty is created, even though
pty is specified 3 times. In a future version of PHP, it might be
possible to do more than just read and write to the pty.
The file descriptor numbers in descriptorspec are not limited to 0, 1
and 2 – you may specify any valid file descriptor number and it will be
passed to the child process. This allows your script to interoperate
with other scripts that run as “co-processes”. *In particular, this is
useful for passing passphrases to programs like PGP, GPG and openssl in
a more secure manner*. It is also useful for reading status information
provided by those programs on auxiliary file descriptors.

Right? Here is my script…

echo "this is a testr"; // Create a pseudo terminal for the child process $descriptorspec = array( 0 => array("pty"),
1 => array("pty"),
2 => array("pty")
$process = proc_open("/usr/bin/passwd", $descriptorspec, $pipes);
if (is_resource($process)) {
fwrite($pipes[0], "mypasswd");

while (!feof($pipes[1])) {
echo fgets($pipes[1], 1024);
// It is important that you close any pipes before calling
// proc_close in order to avoid a deadlock
$return_value = proc_close($process);

echo "command returned $return_valuen";

BUT… when i ran the program:

username:~/Sites/Grid david$ php pty.php
this is a test
Warning: proc_open(): pty is not a valid descriptor spec/mode in
/Users/david/Sites/Grid/pty.php on line 10

$process = proc_open("/usr/bin/passwd", $descriptorspec, $pipes);

Could you help me,please?

> Hi David,


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> No sure it is a newbie question ;) This isn’t one I’ve tried but PHP

> 5+ should

> (in theory) allow this with the proc_open function, covered in the

> second PHP

> CLI article. The manual has some notes

> You need a descriptor spec something like;


> $descriptorspec = array(

> 0 => array(“pty”),

> 1 => array(“pty”),

> 2 => array(“pty”)

> );


> Would be interested to hear how you get on.


>> ———————————————————–

>> From: “David”

>> Message: This is a newbie question, maybe i need a big RTFM. It’s

>> very interesting and useful your two articles “PHP on the Command

>> Line”.


>> I have a big doubt… We are working with PHP 4.3.3 I have to

>> write a PHP script to change a unix user password.


>> Something like that



>> Is possible to do it with PHP? Thank you

>> in advances.

Harry Fuecks is the Engineering Project Lead at Tamedia and formerly the Head of Engineering at Squirro. He is a data-driven facilitator, leader, coach and specializes in line management, hiring software engineers, analytics, mobile, and marketing. Harry also enjoys writing and you can read his articles on SitePoint and Medium.

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