ScotlandPHP

passthru

(PHP 4, PHP 5, PHP 7)

passthru执行外部程序并且显示原始输出

说明

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

exec() 函数类似, passthru() 函数 也是用来执行外部命令(command)的。 当所执行的 Unix 命令输出二进制数据, 并且需要直接传送到浏览器的时候, 需要用此函数来替代 exec()system() 函数。 常用来执行诸如 pbmplus 之类的可以直接输出图像流的命令。 通过设置 Content-type 为 image/gif, 然后调用 pbmplus 程序输出 gif 文件, 就可以从 PHP 脚本中直接输出图像到浏览器。

参数

command

要执行的命令。

return_var

如果提供 return_var 参数, Unix 命令的返回状态会被记录到此参数。

返回值

没有返回值。

注释

Warning

当用户提供的数据传入此函数,使用 escapeshellarg()escapeshellcmd() 来确保用户欺骗系统从而执行任意命令。

Note:

如何程序使用此函数启动,为了能保持在后台运行,此程序必须将输出重定向到文件或其它输出流。否则会导致 PHP 挂起,直至程序执行结束。

Note: 安全模式 启用时,可仅可用 safe_mode_exec_dir 执行文件。实际上,现在不允许在到可执行的路径中存在 .. 组件。

Warning

安全模式 启用时,命令字符串会被 escapeshellcmd() 转换。因此,echo y | echo x 会变成 echo y \| echo x

参见

add a note add a note

User Contributed Notes 20 notes

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9
igor at bboy dot ru
12 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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2
me at yourMomsPussy dot cum
11 months ago
`command` // back ticks drop you out of PHP mode into shell
exec('command', $output); // exec will allow you to capture the return of a command as reference
shell_exec('command'); // will return the output to a variable
system(); //as seen above.
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3
Zak Estrada
12 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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2
swbrown at ucsd dot edu
14 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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3
Chroot
9 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
Paul Giblock
10 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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2
nuker at list dot ru
11 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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2
jo at durchholz dot org
9 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
sarel dot w at envent dot co dot za
12 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
puppy at cyberpuppy dot org
12 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
kpierre at fit dot edu
15 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
16 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
myselfasunder at gmail dot com dot dfvuks
6 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
16 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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-2
vijayramanan at rediffmail dot com
12 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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-2
Stuart Eve
11 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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-2
andreas dot hochsteger at oeamtc dot at
16 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
stuartc1 at NOSPAM dot hotmail dot com
12 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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-3
php @ richud dot com
13 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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-3
jcr at marvel-databadge dot com
14 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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