passthru

(PHP 3, PHP 4, PHP 5)

passthru -- Execute an external program and display raw output

说明

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.

参数

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.

注释

警告

如果想允许用户输入的数据被传入本函数,则应使用 escapeshellarg()escapeshellcmd() 函数来确保用户不能欺骗系统从而执行任意命令。

注: 如果用本函数启动一个程序并希望保持在后台运行,必须确保该程序的输出被重定向到一个文件或者其它输出流去,否则 PHP 会在程序执行结束前挂起。

注: 在打开了安全模式时,只能执行在 safe_mode_exec_dir 之内的程序。为实用起见目前不能在指向程序的路径中包含 .. 成分。

警告

在打开了安全模式时,初始命令字符串之后的所有词都被看成一个单一的参数。因此,echo y | echo x 就成了 echo "y | echo x"


add a note add a note User Contributed Notes
nuker at list dot ru
03-Jan-2006 09:51
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
09-Dec-2005 03:24
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 06:09
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 10:59
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 10:52
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
24-Jun-2005 04:33
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
09-Mar-2005 03:33
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
03-Mar-2005 06:50
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
15-Dec-2004 12:21
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 11:30
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
05-Sep-2003 02:23
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
04-Jun-2003 11:41
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 11:35
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
23-Jan-2002 07:29
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 10:51
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
21-Jun-2001 08:25
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
15-Feb-2001 09:06
About the problem of zombies, you may call a bash script like this:

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

<your command here>
--------------------------