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pclose

Last updated: Sun, 25 Nov 2007

popen

(PHP 4, PHP 5)

popen — プロセスへのファイルポインタをオープンする

説明

resource popen ( string $command , string $mode )

command で指定したコマンドのフォークによってできたプロセスへのパイプをオープンします。

パラメータ

command: コマンド。
mode: モード。

返り値

fopen() により返されたファイルポインタと同様のものを返しますが、それは(読み書きのいずれか一方でのみ使われる)片方向ストリームであり、 pclose() によりクローズされなければならないところが異なります。このポインタは、fgets()、fgetss() および fwrite() のいずれかで使うことができます。

エラーが発生した場合は FALSE を返します。

例

Example#1 popen() の例


<?php
$handle = popen("/bin/ls", "r");
?>

実行すべきコマンドが見つからない場合には、正常なリソースが返されます。おかしなことと思われるかもしれませんが、これには意味があります。これによってシェルから返されたエラーメッセージにアクセスすることができるのです。

Example#2 popen() の例


<?php
error_reporting(E_ALL);

/* リダイレクトにより、標準エラー出力を取得します */
$handle = popen('/path/to/spooge 2>&1', 'r');
echo "'$handle'; " . gettype($handle) . "\n";
$read = fread($handle, 2096);
echo $read;
pclose($handle);
?>

注意

注意: 双方向(two-way)のサポートを求めているのなら、 proc_open() を使用してください。

注意: セーフモードが有効な場合、 safe_mode_exec_dirの中にある実行プログラムのみ実行可能です。実際的な理由により、現在、実行プログラムへのパスに ..を含めることはできません。

警告

セーフモードが有効な場合、コマンド文字列は escapeshellcmd() でエスケープされます。つまり、echo y | echo x は、echo y \| echo x となります。

参考

readfile

" width="11" height="7"/>

pclose

Last updated: Sun, 25 Nov 2007

add a note User Contributed Notes
popen

rockytriton
11-Sep-2007 03:25


Note, when using this with a batch file in windows, you must put an "exit" at the end of your batch file or you will get a new cmd.exe stuck in your process list every time you execute the page.

betchern0t
14-Apr-2007 01:42


Care needs to be taken in the case of long running child processes. Say you want to run tail -f /var/log/messages or in my case burn dvds. If you have a busy wait, Apache2 can sit towards 100%cpu and steadily grow memory. In my case I crashed the server after about an hour and 90% of the dvd burned. During that time apache had consumed a gig of swap.



Offending code - don't copy:



        $ThisCommand = sprintf("%s %s",COMMAND,$ThisFile);

        $fp=popen($ThisCommand,"r");

        while (!feof($fp)) {

                set_time_limit (20);

                $results = fgets($fp, 4096);

                if (strlen($results) == 0) {

                   // stop the browser timing out

                   echo " ";

                   flush();

                } else {

                   $tok = strtok($results, "\n");

                   while ($tok !== false) {

                        echo htmlentities(sprintf("%s\n",$tok))."<br/>";

                        flush();

                        $tok = strtok("\n");

                   }

                }

        }

        pclose($fp);



to go from zero memory and 100% cpu  to negligible memory and negligible cpu add a sleep.



        while (!feof($fp)) {

                set_time_limit (20);

                $results = fgets($fp, 256);

                if (strlen($results) == 0) {

                   // stop the browser timing out

                   echo " ";

                   flush();

                } else {

                   $tok = strtok($results, "\n");

                   while ($tok !== false) {

                        echo htmlentities(sprintf("%s\n",$tok))."<br/>";

                        flush();

                        $tok = strtok("\n");

                   }

                }

                // avoid a busy wait

                sleep(1);



        }



I think the continued banging of the space to keep the browser awake triggered some issues in apache.

Nate
21-Oct-2006 08:21


Note that under Windows, if you are trying to write data to be available to your pipe's STDIN, you may need to execute php directly, rather than depending on file associations.



<?

    // with $cmd set to 'foo.php', STDIN comes up blank.

    // with $cmd set to 'php foo.php', STDIN gets filled

    //     (assuming php.exe is in your path)

    $cmd = 'foo.php';



    if ( ($fh = popen($cmd, 'w')) === false )

        die("Open failed: ${php_errormsg}\n");



    fwrite($fh, "Line one\nLine two\n");



    pclose($fh);

?>

nospam at spamalot dot com
30-Aug-2006 10:19


popen() seems to have problems dealing with binary data (piping audio data to the standard input of an encoding application). I changed to proc_open() instead and now everything is working fine.

php dot net_manual at reimwerker dot de
03-Jun-2006 08:45


If you are going to allow data coming from user input to be passed to this function, then you should keep in mind the following warning that also applies to exec() and system():



http://www.php.net/manual/en/function.exec.php

http://www.php.net/manual/en/function.system.php



Warning:



If you are going to allow data coming from user input to be passed to this function, then you should be using escapeshellarg() or escapeshellcmd() to make sure that users cannot trick the system into executing arbitrary commands.

eric dot liu dot yi at gmail dot com
16-May-2006 02:32


popen() can be used to directly communicate with tools like GNUplot. (And it is platform independent~). To facilitate my work, I made a PHP interface to GNUPlot here:

http://celeste.cn/PHP-GNUPlot/

Christian
10-May-2006 03:33


Thanks a lot to tr4nc3 at msn dot com..

when using apache on Windows XP, on 'console mode' commands work fine, but as a system service, commands like 'popen' stop functioning, to resolve this:



Start>Run>services.msc

Right click "Apache...", select properties.

Click on the "LOG ON" tab

Check the box "Allow this service to interact with desktop"

Click OK

Restart Apache

don at digithink dot com
20-Dec-2005 09:28


// The above import function can be easily extended using 

// /usr/local/bin/xls2csv (part of catdoc ) and popen 

// to read excell files directly. 

// In our particular application the first line was the file heading.

function importxls($file,$head=true,$throwfirst=true,$delim=",",$len=1000) {

   $return = false;

   $handle = popen("/usr/local/bin/xls2csv $file", "r");

// or die if not there.

   if ($throwfirst) {

       $throw = fgetcsv($handle, $len, $delim);

   }

   if ($head) {

       $header = fgetcsv($handle, $len, $delim);

   }

   while (($data = fgetcsv($handle, $len, $delim)) !== FALSE) {

       if ($head AND isset($header)) {

           foreach ($header as $key=>$heading) {

               $row[$heading]=(isset($data[$key])) ? $data[$key] : '';

               print "<li>". $heading ."=>" . $row[$heading]."</li>";

           }

           $return[]=$row;

       } else {

           $return[]=$data;

       }

   }

   fclose($handle);

   return $return;

}

rjl at xs4all dot nl
24-Nov-2005 06:16


Truncated output from ps command?



The solution lies in the way ps displays it's info

specifically the -w option which:

'uses 132 columns to display information,

instead of the default which is your window size.'....

somehow with fgets in php that results in 74 characters

regardless off the init length parameter



a bit of code:



echo '<table width="99%"><tr><td>cron</td></tr>' . "\n";

$fp=popen("/bin/ps -waux","r");

while (!feof($fp)) {

    $buffer = fgets($fp, 4096);

    $croninf .= '<tr><td>' . $buffer . '</td></tr>' . "\n";

}

pclose($fp);

echo $croninf;

echo '</table><br><br>' . "\n";



Ciao,



Rene =<>=

erb at agricola-gymnasium dot de
06-Oct-2005 09:48


Writing and executing a bash script is as simple as that:



$f = popen ("/bin/bash","w");

fwrite($f, "export KRB5CCNAME=`tempfile`\n");

fwrite($f, "export KRBTKFILE=`tempfile`\n");

fwrite($f, "$KINIT --keytab=$GLOBALS["KADMIN_KEYFILE"] --use-keytab --afslog $GLOBALS["KADMIN_PRINC"]\n");

fwrite($f, "pts delete $uid\n");

fwrite($f, "fs rmmount $rwhome\n");

fwrite($f, "vos remove sanjo b user.$uid\n");

fwrite($f, "$KDESTROY\n");

pclose($f);

Cride5
09-Sep-2005 09:39


Here is a nice little script for monitoring your http access log.



<?php



$handle = popen("tail -f /etc/httpd/logs/access.log 2>&1", 'r');

while(!feof($handle)) {

    $buffer = fgets($handle);

    echo "$buffer<br/>\n";

    ob_flush();

    flush();

}

pclose($handle);



?>



----

www.eviltree.co.uk

www.solidsites.co.uk

www.mongbong.com

atampone at NOSPAMFORME dot trdsupra dot com
20-Jun-2005 10:26


If you want to fork a process under windows, this is the function to use.  I created a batch file called runcmd.bat with the following line



start %1 %2 %3 %4



then I have the folowing function



<?

define('RUNCMDPATH', 'c:\\htdocs\\nonwebspace\\runcmd.bat');



function runCmd($cmd) {

    $externalProcess=popen(RUNCMDPATH.' '.$cmd, 'r');

    pclose($externalProcess);

}    

?>



with this, doing something like



<? runCmd('php.exe printWorkOrder.php 3498'); ?>

will launch php.exe outside of apache and allow the script calling the runCmd() function to continue without waiting for the command line process to return.  The process will run under the same user account that Apache (or whatever webserver you're running) is running under, so make sure it has permissions to do whatever you need to do.  Also, make sure that the batch file has enough %n s in order to pass all the command line variables that you might need to pass.



Special thanks to kicken from the devshed forums for coming up with the idea.

electronerd at monolith3d dot com
26-May-2005 03:46


In response to shaun at nospam dot phplabs dot com:



fread() does not guarantee that all the expected data is read. The length argument is only an upper limit. If there isn't more data immediately available, fread() may return early.

PGP Dude
07-May-2005 02:52


I should say, my host uses a modified form of safe mode, so I don't know if that might have caused a problem with "popen" as opposed to "proc_open".  The warning below does NOT appear on the proc_open page:



quote:

With safe mode enabled, all words following the initial command string are treated as a single argument. Thus, echo y | echo x becomes echo "y | echo x".

PGP Dude
07-May-2005 04:30


LinixDude010's srcipt did not work for me.  Seems wrong to read and write with popen, according to the manual.



The script produced pgp text, but there was something wrong with the text and I could not decode it.



This replacement script, using proc_open, which can read and write, DOES work:



<?php

function pgp_encrypt($keyring_location, $public_key_id, $plain_text) {

  $encrypted_text='';

  $key_id = EscapeShellArg($public_key_id);

  putenv("PGPPATH=$keyring_location");



  // encrypt the message

  $descriptorspec = array(

    0 => array("pipe", "r"),  // stdin

    1 => array("pipe", "w"),  // stdout

    2 => array("pipe", "w")   // stderr ?? instead of a file

  );

  $process = proc_open("pgpe -r $key_id -af", $descriptorspec, $pipes);

  if (is_resource($process)) {

    fwrite($pipes[0], $plain_text);

    fclose($pipes[0]);

    while($s= fgets($pipes[1], 1024)) {

          // read from the pipe

          $encrypted_text .= $s;

    }

    fclose($pipes[1]);

    // optional:

    while($s= fgets($pipes[2], 1024)) {

      $encrypted_text.= "\n<p>Error: $s</p>\n";

    }

    fclose($pipes[2]);

  }

  return $encrypted_text;

}



$message = pgp_encrypt("/home/username/.pgp", "to@domain.com", "dummy text to be encrypted");

print nl2br($message);



?>

shaun at nospam dot phplabs dot com
27-Feb-2005 10:52


Note that there appears to be a limit to the amount of data that fread() will return from a handle opened with popen(). A call to fread() may not return as much as you ask for.



For example, suppose I have a file "myfile.txt" which is more than 10KB in size. The following code works as expected:



<?php

$fp = fopen('myfile.txt', 'r');

$data = fread($fp, 10240);

echo strlen($data);

?>



The output is '10240.' However, popen() behaves differently:



<?php

$fp = popen('/bin/cat myfile.txt', 'r');

$data = fread($fp, 10240);

echo strlen($data);

?>



On my system, this code prints out '8192' instead of the expected '10240.'

webmaster at elcurriculum dot com
10-Dec-2004 05:05


This function send an email in html format.



function SendEmail($to,$asunto,$html,$from) {

    $fd = popen("/usr/sbin/sendmail -t", "w");

    fputs($fd, "Content-type: text/html\r\n");

    fputs($fd, "To: $to\r\n");

    fputs($fd, "From: TRYKE <" . $from . ">\r\n");

    fputs($fd, "Subject: $asunto\r\n");

    fputs($fd, "X-Mailer: PHP3\r\n\r\n");

    fputs($fd, $html);

    pclose($fd);

}



Examples:

SendEmail("tryke@hot.com","My Subject","<h1>Hi,<br>How are you?</h1>","miemail@midomain.com");



More:

http://tryke.blogcindario.com

kalvinb602 at hotmail dot com
07-Jul-2004 07:42


If you're having trouble with the server (Apache) hanging when issuing system commands consider the following bug report:



http://bugs.php.net/bug.php?id=22526



basically, if you're using sessions issue a 



session_write_close();



command before you execute your system command to keep the server from hanging.



This may also correct the problem when using other system command executing functions like exec.



Ben

Michel Machado
07-Mar-2004 10:53


Yet another workaround for not having bidirectional pipes in php.



$Cmd =

"bc 2>&1 << END\n" .

"100+221\n" .

"1+3*3\n" .

"quit\n" .

"END\n";



$fp = popen($Cmd, 'r');

$read = fread($fp, 1024);

echo $read;

pclose($fp);

http://vmlinuz.nl/about/contact/
12-Nov-2002 01:58


From the popen linux programmers manual:

<quote>The  command  argument  is  a pointer to a null-terminated string containing a shell command line.  This  command  is passed  to  /bin/sh  using the -c flag.</quote>



Since php uses this popen function, you need to be sure /bin/sh exists. This file may not exist in chroot()ed environments.

ajv-php at erkle dot org
09-Aug-2002 03:02


I noticed that some of the examples above seem to advocate passing unencrypted data to gpg via the pipe shell escape, in the absence of a bi-directional popen (on some OSes).



The approach I've taken is similar to:



  $prefix = 'example';

  $command = '/usr/local/bin/gpg --encrypt --armor --no-tty --batch --no-secmem-warning --recipient "joe.soap@example.com"';

  $tmpfile = tempnam('/tmp', $prefix);

  $pipe = popen("$command 2>&1 >$tmpfile", 'w');

  if (!$pipe) {

    unlink($tmpfile);

  } else {

    fwrite($pipe, $plaintxt, strlen($plaintxt));

    pclose($pipe);

    $fd = fopen($tmpfile, "rb");

    $output = fread($fd, filesize($tmpfile));

    fclose($fd);

    unlink($tmpfile);

  }

  return $output;



This means that unencrypted information is not passed via a (potentially readable) shell command, and only encrypted information gets stored on disc.

12-Jul-2002 06:33


Here is a workaround for not having bidirectional pipes in php.



If you have bidirectional pipe support, don't bother with this.



The trick here is to send the input on the command line to the target application.  In particular I wanted to use openssl without using temp files or named pipes.  This solution should also be thread/process safe.



This does work on Linux (RedHat 7).



function filterThroughCmd($input, $commandLine) {

  $pipe = popen("echo \"$input\"|$commandLine" , 'r');

  if (!$pipe) {

    print "pipe failed.";

    return "";

  }

  $output = '';

  while(!feof($pipe)) {

    $output .= fread($pipe, 1024);

  }

  pclose($pipe);

  return $output;

}



# example:

print filterThroughCmd("hello", "cat");

# Piping to cat has the effect of echoing your input.

cyberlot at cyberlot dot net
01-Jul-2002 05:29


The below code works for both way processing ;) Have fun folks



<?

    system("mkfifo pipeout");

   $pipe = popen("./nwserver -module Chapter1E > pipeout","w");

   $pipeout = fopen("pipeout", "r");

   while ($s = fgets($pipeout,1024)) {

    echo $s;

   }



?>

linuxdude010 at yahoo dot com
25-May-2002 03:49


I had all kinds of trouble encrypting a message with PGP, but I finanlly got it to work.  The trick was to 'chmod o+r pubring.pkr' so that the apache server could read the public keys!!!  Then, this function worked fine:



<?PHP

function pgp_encrypt($keyring_location, $public_key_id, $plain_text) {



        $key_id = EscapeShellArg($public_key_id);

        putenv("PGPPATH=$keyring_location");



        // encrypt the message

        $pipe = popen("pgpe -r $key_id -af", "r");               

        fwrite($pipe, $plain_text);

        $encrypted_text = '';

        while($s = fgets($pipe, 1024)) {

                // read from the pipe

                $encrypted_text .= $s;

        }

        pclose($pipe);



        return $encrypted_text;

}



$message = pgp_encrypt("/home/username/.pgp", "to@domain.com", "dummy text to be encrypted");

print nl2br($message);



?>

nricciardi at mindspring dot com
09-Mar-2002 09:38


ive tried using popen using bidirectional pipes without working for obvious reasons, but i managed to create a simple script that managed to take care of the problem.  This example is for gpg encryption.



<?

   $message = "this is the text to encrypt with gpg";

   $sendto = 'Dummy Key <another@fake.email>';



   system("mkfifo pipein");

   system("mkfifo pipeout");

   system("gpg --encrypt -a -r '$sendto' > pipeout < pipein &");

   $fo = fopen("pipeout", "r");

   $fi = fopen("pipein", "w");

   fwrite($fi, $message, strlen($message));

   fclose($fi);

   while (!feof($fo)) {

      $buf .= fread($fo, 1024);

   }

   echo $buf;

   unlink("pipein");

   unlink("pipeout");

?>



If anyone has a better way of doing this I would love to see it.

kevin at pricetrak dot com
30-Jun-2001 03:26


Just a quick note about your environment. None of the apache specific environment variables are available to the called program.

trevor at verite dot com
17-Feb-2001 05:42


Just make sure that you check the user information being passed into the command (if any) before it executes.

bevmo at gmx dot de
02-Dec-2000 03:27


Try this if you want to use sendmail...


$mailer = popen ("/usr/sbin/sendmail -t -i","w");


fwrite ($mailer,"Subject: 


From: 


To: 





*insert text*


");


pclose ($mailer);

matthew at leftcoast dot com
04-Oct-2000 10:16


Note that your OS must support bi-direction pipes for popen to be bi-directional.  





FreeBSD and BSDI are known to support bi-pipes.  





Not sure about Linux.

add a note

readfile

" width="11" height="7"/>

pclose

Last updated: Sun, 25 Nov 2007