passthru

(PHP 4, PHP 5)

passthruEsegue un programma esterno e mostra l'output non elaborato

Descrizione

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

La funzione passthru() è simile alla funzione exec() inquanto esegue command. Se il parametro return_var è specificato, lo stato ritornato dal comando Unix verrà posto lì. Questa funzione deve essere usata al posto di exec() o di system() quando l'output del comando Unix consiste in dati binari da passare direttamente al browser. Un suo uso frequente consiste nel eseguire, ad esempio, le utility pbmplus che possono restituire un flusso diretto all'immagine. Impostado il tipo di contenuto a image/gif e successivamente chiamando un programma pbmplus per generare una gif puoi realizzare uno script PHP che genera direttamente immagini.

Avviso

Se si permette di passare a questa funzione i dati provenineti dagli input utente, si dovrebbe utilizzare la funzione escapeshellarg() oppure escapeshellcmd() in modo da essere sicuri che gli utenti non possano compromettere il sistema eseguendo comandi arbitrari.

Nota:

Se si avvia un programma con questa funzione e si vuole lasciarlo in esecuzione in background, ci si deve accertare che l'output del programma venga redirezionato verso un file o qualche altro stream di output, altrimenti PHP si fermerà finché l'esecuzione del programma sarà terminata.

Nota: Quando si abilita la modalità sicura, si può eseguire soltanto gli eseguibili presenti nella directory safe_mode_exec_dir. Per motivi pratici, attualmente, non è permesso avere .. come componente del percorso di un eseguibile.

Avviso

Con la modalità sicura attivata, tutte le parole che seguono il comando iniziale sono trattate come argomenti. Quindi, echo y | echo x diventa echo "y | echo x".

Vedere anche exec(), system(), popen(), escapeshellcmd(), e l'operatore backtick.

add a note add a note

User Contributed Notes 19 notes

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10
igor at bboy dot ru
9 years ago
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.
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4
Chroot
6 years ago
If you have chrooted apache and php, you will also want to put /bin/sh into the chrooted environment. Otherwise, the exec() or passthru() will not function properly, and will produce error code 127, file not found.
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2
myselfasunder at gmail dot com dot dfvuks
4 years ago
PHP's program-execution commands fail miserably when it comes to STDERR, and the proc_open() command doesn't work all that consistently in non-blocking mode under Windows.

This command, although useful, is no different. To form a mechanism that will see/capture both STDOUT and STDERR output, pipe the command to the 'tee' command (which can be found for Windows), and wrap the whole thing in output buffering.

Dustin Oprea
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1
PJ at piggei dot com
13 years ago
About the problem of zombies, you may call a bash script like this:

--------------------------
#! /bin/bash
ulimit -t 60

<your command here>
--------------------------
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1
stuartc1 at NOSPAM dot hotmail dot com
9 years ago
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().
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1
sarel dot w at envent dot co dot za
9 years ago
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.
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1
swbrown at ucsd dot edu
11 years ago
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.
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0
puppy at cyberpuppy dot org
9 years ago
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.
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0
Zak Estrada
10 years ago
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).
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0
php @ richud dot com
10 years ago
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.
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0
jcr at marvel-databadge dot com
11 years ago
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.
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0
kpierre at fit dot edu
12 years ago
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
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0
sidney at jigsaw dot nl
13 years ago
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!
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-1
jo at durchholz dot org
7 years ago
Note to Paul Giblock: the command *is* run through the shell.
You can verify this on any Linux system with

<?php
passthru
('echo $PATH');
?>

You'll get the content of the PATH environment variable, not the string $PATH.
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-1
vijayramanan at rediffmail dot com
9 years ago
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!!!!!
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-1
nuker at list dot ru
8 years ago
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;
?>
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-1
andreas dot hochsteger at oeamtc dot at
13 years ago
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).
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-1
Paul Giblock
7 years ago
Stuart:

The pasthru function does not execute the program through the shell.  What this mean, among other things, is that your PATH variable is never set.  Therefore, you have to use full paths on everything.

I believe system() will run your program underneith a shell.  This allow the program to run in a 'normal' environment.

-Paul
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-1
Stuart Eve
9 years ago
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);
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