PHP: passthru - Manual

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Last updated: Fri, 26 Jan 2007

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# passthru

(PHP 3, PHP 4, PHP 5)

passthru -- Execute an external program and display raw output

## Описание

void passthru ( string command [, int &return_var] )

The passthru() function is similar to the exec() function in that it executes a `command`. This function should be used in place of exec() or system() when the output from the Unix command is binary data which needs to be passed directly back to the browser. A common use for this is to execute something like the pbmplus utilities that can output an image stream directly. By setting the Content-type to image/gif and then calling a pbmplus program to output a gif, you can create PHP scripts that output images directly.

## Список параметров

`command`

  The command that will be executed.

`return_var`

  If the `return_var` argument is present, the return status of the Unix command will be placed here.

## Примечания

Внимание
Если вы собираетесь передавать функции данные, отправленные пользователем, вы должны использовать функции escapeshellarg() или escapeshellcmd() для того, чтобы обезопасить исполнение команд.

> Замечание: Если вы собираетесь использовать эту функцию в программе, работающей в качестве демона, убедитесь, что стандартный вывод функции направлен в файл или другой поток, в противном случае PHP зависнет вплоть до конца выполнения программы.

> Замечание: В случае работы в безопасном режиме, вы можете запускать что-либо только в пределах safe_mode_exec_dir. В настоящее время, использование `..` в пути запрещено

Внимание
В случае работы в безопасном режиме, все слова, следующие за начальной командой, рассматриваются как единый аргумент. То есть `echo y | echo x` будет работать как `echo "y | echo x"`.

## Смотрите также

exec()
system()
popen()
escapeshellcmd()
backtick operator

add a note User Contributed Notes
passthru
nuker at list dot ru
03-Jan-2006 05:51
`I wrote function, that gets proxy server value from the Internet Explorer (from
registry). It was tested in Windows XP Pro
(Sorry for my English)
<?php
function getProxyFromIE()
{
exec("reg query \"HKEY_CURRENT_USER\Software\Microsoft".
"\Windows\CurrentVersion\Internet Settings\" /v ProxyEnable",
$proxyenable,$proxyenable_status);
exec("reg query \"HKEY_CURRENT_USER\Software\Microsoft".
"\Windows\CurrentVersion\Internet Settings\" /v ProxyServer",
$proxyserver);
if($proxyenable_status!=0)
return false; #Can't access the registry! Very very bad...
else
{
$enabled=substr($proxyenable[4],-1,1);
if($enabled==0)
return false;
else
{
$proxy=ereg_replace("^[ \t]{1,10}ProxyServer\tREG_SZ[ \t]{1,20}","",
$proxyserver[4]);
if(ereg("[\=\;]",$proxy))
{
$proxy=explode(";",$proxy);
foreach($proxy as $i => $v)
{
if(ereg("http",$v))
{
$proxy=str_replace("http=","",$v);
break;
}
}
if(@!ereg("^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\:".
"[0-9]{1,5}$",$proxy))
return false;
else
return $proxy;
}
else
return $proxy;
}
}
}
?>
Note, that this function returns FALSE if proxy is disabled in Internet
Explorer. This function returns ONLY HTTP proxy server.
Usage:
<?php
$proxy=getProxyFromIE();
if(!$proxy)
echo "Can't get proxy!";
else
echo $proxy;
?>`
Stuart Eve
08-Dec-2005 11:24
`I dunno if anyone else might find this useful, but when I was trying to use the passthru() command on Suse9.3 I was having no success with the command:
$command = 'gdal_translate blahahahaha';
passthru($command);
It only worked once I put:
$command = '/usr/bin/local/gdal_translate blalalala';
passthru($command);`
vijayramanan at rediffmail dot com
13-Oct-2005 03:09
`I had an issue when i used exec
I think we were echoing information on the test.php script.
for eg: when we tried
exec(php test.php,$array,$error);
the return was 127 and the code was failing.
checking the note on this page gave us a hint to use passthru instead.
The only thing to note is that you need to provide the fuull path.
now our command became
passthru(/bin/php /pathtotest/test.php,$array,$error);
this works.
yipeee!!!!!`
waldow at NOSPAM dot chem dot plu dot edu
22-Sep-2005 07:59
`When upgrading my redhat server to enterprise 4, selinux was turned on. This caused one of my php scripts (that uses passthru) to fail. After some nice help from redhat, I was able to get the script running again. Here is what helped me.
If you get permission errors (in /var/log/httpd/error_log) which seem to be from selinux (and not standard chmod or chown issues), make sure that the folder you are using is not in /tmp and has the selinux context of httpd_sys_script_rw_t as can be set as follows:
chcon -t httpd_sys_script_rw_t folder_name
Hope this helps someone...`
stuartc1 at NOSPAM dot hotmail dot com
09-Aug-2005 07:52
`Thought it might beuseful to note the passthru seems to supress error messages whilst being run in Dos on Windows (test on NT).
To show FULL raw output including errors, use system().`
igor at bboy dot ru
23-Jun-2005 01:33
`If you are using passthru() to download files (for dynamically generated content or something outside webserver root) using similar code:
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"myfile.zip\"");
header("Content-Length: 11111");
passthru("cat myfile.zip",$err);
and your download goes fine, but subsequent downloads / link clicks are screwed up, with headers and binary data being all over the website, try putting
exit();
after the passthrough. This will exit the script after the download is done and will not interfere with any future actions.`
sarel dot w at envent dot co dot za
08-Mar-2005 11:33
`Zak Estrada
14-Dec-2004 11:21
Remember to use the full path (IE '/usr/local/bin/foo' instead of 'foo') when using passthru, otherwise you'll get an exit code of 127 (command not found).
Remember, you'll also get this error if your file does not have executable permission.`
puppy at cyberpuppy dot org
02-Mar-2005 02:50
`Regarding swbrown's comment...you need to use an output buffer if you don't want the data displayed.
For example:
ob_start();
passthru("<i>command</i>");
$var = ob_get_contents();
ob_end_clean(); //Use this instead of ob_flush()
This gets all the output from the command, and exits without sending any data to stdout.`
Zak Estrada
14-Dec-2004 08:21
`Remember to use the full path (IE '/usr/local/bin/foo' instead of 'foo') when using passthru, otherwise you'll get an exit code of 127 (command not found).`
php @ richud dot com
27-May-2004 08:30
`Regarding kpierre's post, be mindful that if you shell script errors, you will find the error output from it in the base error_log file (not virtualhost error_log) in apache.`
jcr at marvel-databadge dot com
04-Sep-2003 11:23
`With apache 2.x on RH9 passthru() writes 1 byte at a time. Apache 2.x buffers and chunk encodes the output for you - but the chunked encoding devides the output in chunks of 1 byte each...thus several bytes of overhead per byte. I guess that buffering behaviour is by design - but caused problems for me with IE adobe acrobot 5 plugin. The plugin doesn't like like it if you send it a stream of 1 byte chunks - it tells you your file is not a pdf or gives a blank screen. Using output buffering (ob_start / ob_endflush) gives reasonable size chunks and the plugin works OK.`
swbrown at ucsd dot edu
03-Jun-2003 08:41
`passthru() seems absolutely determined to buffer output no matter what you do, even with ob_implicit_flush(). The solution seems to be to use popen() instead.`
kpierre at fit dot edu
30-Jan-2002 07:35
`The documention does not mention that passthru() will only display standard output and not standard error.
If you are running a script you can pipe the STDERR to STDOUT by doing
exec 2>&1
Eg. the script below will actually print something with the passthru() function...
#!/bin/sh
exec 2>&1
ulimit -t 60
cat nosuchfile.txt`
mike at ftl dot com
22-Jan-2002 03:29
`In reference to aborted scripts hanging. You can set 'ignore_user_abort(true);' in your script and it does exactly that.
It causes the browser to stop loading but the script will continue.`
andreas dot hochsteger at oeamtc dot at
03-Oct-2001 07:51
`If you sometimes get no output from passthru() use system() instead. This solved this problem for me (php 4.0.5 on Tru64 Unix compiled with gcc).`
sidney at jigsaw dot nl
20-Jun-2001 05:25
`PJ's ulimit example is nice; however, if you include multiple commands in the script after the ulimit command, each gets its own, seperate 60 second time slot!<br>
Furthermore, these sixty seconds are *CPU* time. Most programs hang for other reasons than CPU hogging (for example, waiting for a database connection) so for most purposes the number 60 is rather too high.<br>
Try "ulimit -t 1" first, which will give you about 10^9 cycles on modern hardware -- quite enough to get a lot of work done!`
PJ at piggei dot com
14-Feb-2001 05:06
`About the problem of zombies, you may call a bash script like this:
--------------------------
#! /bin/bash
ulimit -t 60
<your command here>
--------------------------`
add a note
proc_close exec

Last updated: Fri, 26 Jan 2007
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